1
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Aviner R, Lee TT, Masto VB, Li KH, Andino R, Frydman J. Polyglutamine-mediated ribotoxicity disrupts proteostasis and stress responses in Huntington's disease. Nat Cell Biol 2024; 26:892-902. [PMID: 38741019 DOI: 10.1038/s41556-024-01414-x] [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: 12/07/2023] [Accepted: 04/01/2024] [Indexed: 05/16/2024]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat in the Huntingtin (HTT) gene, encoding a homopolymeric polyglutamine (polyQ) tract. Although mutant HTT (mHTT) protein is known to aggregate, the links between aggregation and neurotoxicity remain unclear. Here we show that both translation and aggregation of wild-type HTT and mHTT are regulated by a stress-responsive upstream open reading frame and that polyQ expansions cause abortive translation termination and release of truncated, aggregation-prone mHTT fragments. Notably, we find that mHTT depletes translation elongation factor eIF5A in brains of symptomatic HD mice and cultured HD cells, leading to pervasive ribosome pausing and collisions. Loss of eIF5A disrupts homeostatic controls and impairs recovery from acute stress. Importantly, drugs that inhibit translation initiation reduce premature termination and mitigate this escalating cascade of ribotoxic stress and dysfunction in HD.
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Affiliation(s)
- Ranen Aviner
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub San Francisco, San Francisco, CA, USA
| | - Ting-Ting Lee
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
| | - Vincent B Masto
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
| | - Kathy H Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Judith Frydman
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA.
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2
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Lu HJ, Koju N, Sheng R. Mammalian integrated stress responses in stressed organelles and their functions. Acta Pharmacol Sin 2024; 45:1095-1114. [PMID: 38267546 PMCID: PMC11130345 DOI: 10.1038/s41401-023-01225-0] [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: 06/29/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
The integrated stress response (ISR) triggered in response to various cellular stress enables mammalian cells to effectively cope with diverse stressful conditions while maintaining their normal functions. Four kinases (PERK, PKR, GCN2, and HRI) of ISR regulate ISR signaling and intracellular protein translation via mediating the phosphorylation of eukaryotic translation initiation factor 2 α (eIF2α) at Ser51. Early ISR creates an opportunity for cells to repair themselves and restore homeostasis. This effect, however, is reversed in the late stages of ISR. Currently, some studies have shown the non-negligible impact of ISR on diseases such as ischemic diseases, cognitive impairment, metabolic syndrome, cancer, vanishing white matter, etc. Hence, artificial regulation of ISR and its signaling with ISR modulators becomes a promising therapeutic strategy for relieving disease symptoms and improving clinical outcomes. Here, we provide an overview of the essential mechanisms of ISR and describe the ISR-related pathways in organelles including mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. Meanwhile, the regulatory effects of ISR modulators and their potential application in various diseases are also enumerated.
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Affiliation(s)
- Hao-Jun Lu
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China
| | - Nirmala Koju
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China
| | - Rui Sheng
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China.
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3
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Oliveira MM, Mohamed M, Elder MK, Banegas-Morales K, Mamcarz M, Lu EH, Golhan EAN, Navrange N, Chatterjee S, Abel T, Klann E. The integrated stress response effector GADD34 is repurposed by neurons to promote stimulus-induced translation. Cell Rep 2024; 43:113670. [PMID: 38219147 PMCID: PMC10964249 DOI: 10.1016/j.celrep.2023.113670] [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: 07/04/2023] [Revised: 10/11/2023] [Accepted: 12/26/2023] [Indexed: 01/16/2024] Open
Abstract
Neuronal protein synthesis is required for long-lasting plasticity and long-term memory consolidation. Dephosphorylation of eukaryotic initiation factor 2α is one of the key translational control events that is required to increase de novo protein synthesis that underlies long-lasting plasticity and memory consolidation. Here, we interrogate the molecular pathways of translational control that are triggered by neuronal stimulation with brain-derived neurotrophic factor (BDNF), which results in eukaryotic initiation factor 2α (eIF2α) dephosphorylation and increases in de novo protein synthesis. Primary rodent neurons exposed to BDNF display elevated translation of GADD34, which facilitates eIF2α dephosphorylation and subsequent de novo protein synthesis. Furthermore, GADD34 requires G-actin generated by cofilin to dephosphorylate eIF2α and enhance protein synthesis. Finally, GADD34 is required for BDNF-induced translation of synaptic plasticity-related proteins. Overall, we provide evidence that neurons repurpose GADD34, an effector of the integrated stress response, as an orchestrator of rapid increases in eIF2-dependent translation in response to plasticity-inducing stimuli.
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Affiliation(s)
| | - Muhaned Mohamed
- Center for Neural Science, New York University, New York, NY, USA
| | - Megan K Elder
- Center for Neural Science, New York University, New York, NY, USA
| | | | - Maggie Mamcarz
- Center for Neural Science, New York University, New York, NY, USA
| | - Emily H Lu
- Center for Neural Science, New York University, New York, NY, USA
| | - Ela A N Golhan
- Center for Neural Science, New York University, New York, NY, USA
| | - Nishika Navrange
- Center for Neural Science, New York University, New York, NY, USA
| | - Snehajyoti Chatterjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA; NYU Neuroscience Institute, New York University School of Medicine, New York, NY, USA.
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4
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Kalinin A, Zubkova E, Menshikov M. Integrated Stress Response (ISR) Pathway: Unraveling Its Role in Cellular Senescence. Int J Mol Sci 2023; 24:17423. [PMID: 38139251 PMCID: PMC10743681 DOI: 10.3390/ijms242417423] [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: 11/02/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Cellular senescence is a complex process characterized by irreversible cell cycle arrest. Senescent cells accumulate with age, promoting disease development, yet the absence of specific markers hampers the development of selective anti-senescence drugs. The integrated stress response (ISR), an evolutionarily highly conserved signaling network activated in response to stress, globally downregulates protein translation while initiating the translation of specific protein sets including transcription factors. We propose that ISR signaling plays a central role in controlling senescence, given that senescence is considered a form of cellular stress. Exploring the intricate relationship between the ISR pathway and cellular senescence, we emphasize its potential as a regulatory mechanism in senescence and cellular metabolism. The ISR emerges as a master regulator of cellular metabolism during stress, activating autophagy and the mitochondrial unfolded protein response, crucial for maintaining mitochondrial quality and efficiency. Our review comprehensively examines ISR molecular mechanisms, focusing on ATF4-interacting partners, ISR modulators, and their impact on senescence-related conditions. By shedding light on the intricate relationship between ISR and cellular senescence, we aim to inspire future research directions and advance the development of targeted anti-senescence therapies based on ISR modulation.
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Affiliation(s)
- Alexander Kalinin
- National Medical Research Centre of Cardiology Named after Academician E.I. Chazov, 121552 Moscow, Russia; (A.K.); (E.Z.)
- Faculty of Fundamental Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Ekaterina Zubkova
- National Medical Research Centre of Cardiology Named after Academician E.I. Chazov, 121552 Moscow, Russia; (A.K.); (E.Z.)
| | - Mikhail Menshikov
- National Medical Research Centre of Cardiology Named after Academician E.I. Chazov, 121552 Moscow, Russia; (A.K.); (E.Z.)
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5
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Hicks D, Giresh K, Wrischnik LA, Weiser DC. The PPP1R15 Family of eIF2-alpha Phosphatase Targeting Subunits (GADD34 and CReP). Int J Mol Sci 2023; 24:17321. [PMID: 38139150 PMCID: PMC10743859 DOI: 10.3390/ijms242417321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The vertebrate PPP1R15 family consists of the proteins GADD34 (growth arrest and DNA damage-inducible protein 34, the product of the PPP1R15A gene) and CReP (constitutive repressor of eIF2α phosphorylation, the product of the PPP1R15B gene), both of which function as targeting/regulatory subunits for protein phosphatase 1 (PP1) by regulating subcellular localization, modulating substrate specificity and assembling complexes with target proteins. The primary cellular function of these proteins is to facilitate the dephosphorylation of eukaryotic initiation factor 2-alpha (eIF2α) by PP1 during cell stress. In this review, we will provide a comprehensive overview of the cellular function, biochemistry and pharmacology of GADD34 and CReP, starting with a brief introduction of eIF2α phosphorylation via the integrated protein response (ISR). We discuss the roles GADD34 and CReP play as feedback inhibitors of the unfolded protein response (UPR) and highlight the critical function they serve as inhibitors of the PERK-dependent branch, which is particularly important since it can mediate cell survival or cell death, depending on how long the stressful stimuli lasts, and GADD34 and CReP play key roles in fine-tuning this cellular decision. We briefly discuss the roles of GADD34 and CReP homologs in model systems and then focus on what we have learned about their function from knockout mice and human patients, followed by a brief review of several diseases in which GADD34 and CReP have been implicated, including cancer, diabetes and especially neurodegenerative disease. Because of the potential importance of GADD34 and CReP in aspects of human health and disease, we will discuss several pharmacological inhibitors of GADD34 and/or CReP that show promise as treatments and the controversies as to their mechanism of action. This review will finish with a discussion of the biochemical properties of GADD34 and CReP, their regulation and the additional interacting partners that may provide insight into the roles these proteins may play in other cellular pathways. We will conclude with a brief outline of critical areas for future study.
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Affiliation(s)
- Danielle Hicks
- Department of Science, Mathematics and Engineering, Modesto Junior College, Modesto, CA 95350, USA
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Krithika Giresh
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Lisa A. Wrischnik
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Douglas C. Weiser
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
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6
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Chen S, Wang Q, Wang H, Xia S. Endoplasmic reticulum stress in T cell-mediated diseases. Scand J Immunol 2023; 98:e13307. [PMID: 38441291 DOI: 10.1111/sji.13307] [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: 01/17/2023] [Revised: 05/23/2023] [Accepted: 06/18/2023] [Indexed: 03/07/2024]
Abstract
T cells synthesize a large number of proteins during their development, activation, and differentiation. The build-up of misfolded and unfolded proteins in the endoplasmic reticulum, however, causes endoplasmic reticulum (ER) stress. Thus, T cells can maintain ER homeostasis via endoplasmic reticulum-associated degradation, unfolded protein response, and autophagy. In T cell-mediated diseases, such as rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, type 1 diabetes and vitiligo, ER stress caused by changes in the internal microenvironment can cause disease progression by affecting T cell homeostasis. This review discusses ER stress in T cell formation, activation, differentiation, and T cell-mediated illnesses, and may offer new perspectives on the involvement of T cells in autoimmune disorders and cancer.
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Affiliation(s)
- Shaodan Chen
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Qiulei Wang
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Hui Wang
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Sheng Xia
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
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7
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Saeed H, Leibowitz BJ, Zhang L, Yu J. Targeting Myc-driven stress addiction in colorectal cancer. Drug Resist Updat 2023; 69:100963. [PMID: 37119690 DOI: 10.1016/j.drup.2023.100963] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/06/2023] [Accepted: 04/17/2023] [Indexed: 05/01/2023]
Abstract
MYC is a proto-oncogene that encodes a powerful regulator of transcription and cellular programs essential for normal development, as well as the growth and survival of various types of cancer cells. MYC rearrangement and amplification is a common cause of hematologic malignancies. In epithelial cancers such as colorectal cancer, genetic alterations in MYC are rare. Activation of Wnt, ERK/MAPK, and PI3K/mTOR pathways dramatically increases Myc levels through enhanced transcription, translation, and protein stability. Elevated Myc promotes stress adaptation, metabolic reprogramming, and immune evasion to drive cancer development and therapeutic resistance through broad changes in transcriptional and translational landscapes. Despite intense interest and effort, Myc remains a difficult drug target. Deregulation of Myc and its targets has profound effects that vary depending on the type of cancer and the context. Here, we summarize recent advances in the mechanistic understanding of Myc-driven oncogenesis centered around mRNA translation and proteostress. Promising strategies and agents under development to target Myc are also discussed with a focus on colorectal cancer.
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Affiliation(s)
- Haris Saeed
- UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA; Dept. of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA
| | - Brian J Leibowitz
- UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA; Dept. of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA
| | - Lin Zhang
- UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA; Dept. of Chemical Biology and Pharmacology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA
| | - Jian Yu
- UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA; Dept. of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA; Dept. of Radiation Oncology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA 15213, USA.
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8
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Pharmacological targeting of endoplasmic reticulum stress in disease. Nat Rev Drug Discov 2021; 21:115-140. [PMID: 34702991 DOI: 10.1038/s41573-021-00320-3] [Citation(s) in RCA: 181] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2021] [Indexed: 02/08/2023]
Abstract
The accumulation of misfolded proteins in the endoplasmic reticulum (ER) leads to ER stress, resulting in activation of the unfolded protein response (UPR) that aims to restore protein homeostasis. However, the UPR also plays an important pathological role in many diseases, including metabolic disorders, cancer and neurological disorders. Over the last decade, significant effort has been invested in targeting signalling proteins involved in the UPR and an array of drug-like molecules is now available. However, these molecules have limitations, the understanding of which is crucial for their development into therapies. Here, we critically review the existing ER stress and UPR-directed drug-like molecules, highlighting both their value and their limitations.
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9
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Jobava R, Mao Y, Guan BJ, Hu D, Krokowski D, Chen CW, Shu XE, Chukwurah E, Wu J, Gao Z, Zagore LL, Merrick WC, Trifunovic A, Hsieh AC, Valadkhan S, Zhang Y, Qi X, Jankowsky E, Topisirovic I, Licatalosi DD, Qian SB, Hatzoglou M. Adaptive translational pausing is a hallmark of the cellular response to severe environmental stress. Mol Cell 2021; 81:4191-4208.e8. [PMID: 34686314 PMCID: PMC8559772 DOI: 10.1016/j.molcel.2021.09.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/27/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022]
Abstract
To survive, mammalian cells must adapt to environmental challenges. While the cellular response to mild stress has been widely studied, how cells respond to severe stress remains unclear. We show here that under severe hyperosmotic stress, cells enter a transient hibernation-like state in anticipation of recovery. We demonstrate this adaptive pausing response (APR) is a coordinated cellular response that limits ATP supply and consumption through mitochondrial fragmentation and widespread pausing of mRNA translation. This pausing is accomplished by ribosome stalling at translation initiation codons, which keeps mRNAs poised to resume translation upon recovery. We further show that recovery from severe stress involves ISR (integrated stress response) signaling that permits cell cycle progression, resumption of growth, and reversal of mitochondria fragmentation. Our findings indicate that cells can respond to severe stress via a hibernation-like mechanism that preserves vital elements of cellular function under harsh environmental conditions.
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Affiliation(s)
- Raul Jobava
- Department of Biochemistry, CWRU, Cleveland, OH 44106, USA; Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA
| | - Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Bo-Jhih Guan
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA
| | - Di Hu
- Department of Physiology & Biophysics, CWRU, Cleveland, OH 44106, USA
| | - Dawid Krokowski
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA; Department of Molecular Biology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin 20-033, Poland
| | - Chien-Wen Chen
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA
| | - Xin Erica Shu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Evelyn Chukwurah
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA
| | - Jing Wu
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA
| | - Zhaofeng Gao
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA
| | - Leah L Zagore
- Department of Biochemistry, CWRU, Cleveland, OH 44106, USA; Center for RNA Science and Therapeutics, CWRU, Cleveland, OH 44106, USA
| | | | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Medical Faculty, University of Cologne, 50931 Cologne, Germany; Institute for Mitochondrial Diseases and Ageing, Medical Faculty and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Andrew C Hsieh
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Saba Valadkhan
- Department of Molecular Biology and Microbiology, CWRU, Cleveland, OH 44106, USA
| | - Youwei Zhang
- Department of Pharmacology, CWRU, Cleveland, OH 44106, USA
| | - Xin Qi
- Department of Physiology & Biophysics, CWRU, Cleveland, OH 44106, USA
| | - Eckhard Jankowsky
- Department of Biochemistry, CWRU, Cleveland, OH 44106, USA; Center for RNA Science and Therapeutics, CWRU, Cleveland, OH 44106, USA
| | - Ivan Topisirovic
- Gerald Bronfman Department of Oncology, Departments of Biochemistry and Experimental Medicine and Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC H3T 1E2, Canada
| | - Donny D Licatalosi
- Department of Biochemistry, CWRU, Cleveland, OH 44106, USA; Center for RNA Science and Therapeutics, CWRU, Cleveland, OH 44106, USA.
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
| | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH 44106, USA.
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10
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Guo B, Xiong X, Hasani S, Wen YA, Li AT, Martinez R, Skaggs AT, Gao T. Downregulation of PHLPP induced by endoplasmic reticulum stress promotes eIF2α phosphorylation and chemoresistance in colon cancer. Cell Death Dis 2021; 12:960. [PMID: 34663797 PMCID: PMC8523518 DOI: 10.1038/s41419-021-04251-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022]
Abstract
Aberrant activation of endoplasmic reticulum (ER) stress by extrinsic and intrinsic factors contributes to tumorigenesis and resistance to chemotherapies in various cancer types. Our previous studies have shown that the downregulation of PHLPP, a novel family of Ser/Thr protein phosphatases, promotes tumor initiation, and progression. Here we investigated the functional interaction between the ER stress and PHLPP expression in colon cancer. We found that induction of ER stress significantly decreased the expression of PHLPP proteins through a proteasome-dependent mechanism. Knockdown of PHLPP increased the phosphorylation of eIF2α as well as the expression of autophagy-associated genes downstream of the eIF2α/ATF4 signaling pathway. In addition, results from immunoprecipitation experiments showed that PHLPP interacted with eIF2α and this interaction was enhanced by ER stress. Functionally, knockdown of PHLPP improved cell survival under ER stress conditions, whereas overexpression of a degradation-resistant mutant PHLPP1 had the opposite effect. Taken together, our studies identified ER stress as a novel mechanism that triggers PHLPP downregulation; and PHLPP-loss promotes chemoresistance by upregulating the eIF2α/ATF4 signaling axis in colon cancer cells.
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Affiliation(s)
- Bianqin Guo
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Xiaopeng Xiong
- Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Sumati Hasani
- Markey Cancer Center, University of Kentucky, Lexington, KY, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Yang-An Wen
- Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Austin T Li
- Paul Laurence Dunbar High School, Lexington, KY, USA
- Princeton University, Princeton, NJ, USA
| | - Rebecca Martinez
- Agricultural and Medical Biotechnology Program, College of Agriculture, Food & Environment, University of Kentucky, Lexington, KY, USA
| | - Ashley T Skaggs
- Markey Cancer Center, University of Kentucky, Lexington, KY, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Tianyan Gao
- Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA.
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11
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Matos B, Howl J, Jerónimo C, Fardilha M. Modulation of serine/threonine-protein phosphatase 1 (PP1) complexes: A promising approach in cancer treatment. Drug Discov Today 2021; 26:2680-2698. [PMID: 34390863 DOI: 10.1016/j.drudis.2021.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/23/2021] [Accepted: 08/05/2021] [Indexed: 01/21/2023]
Abstract
Cancer is the second leading cause of death worldwide. Despite the availability of numerous therapeutic options, tumor heterogeneity and chemoresistance have limited the success of these treatments, and the development of effective anticancer therapies remains a major focus in oncology research. The serine/threonine-protein phosphatase 1 (PP1) and its complexes have been recognized as potential drug targets. Research on the modulation of PP1 complexes is currently at an early stage, but has immense potential. Chemically diverse compounds have been developed to disrupt or stabilize different PP1 complexes in various cancer types, with the objective of inhibiting disease progression. Beneficial results obtained in vitro now require further pre-clinical and clinical validation. In conclusion, the modulation of PP1 complexes seems to be a promising, albeit challenging, therapeutic strategy for cancer.
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Affiliation(s)
- Bárbara Matos
- Laboratory of Signal Transduction, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal; Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Institute of Oncology of Porto (IPO Porto), 4200-072 Porto, Portugal
| | - John Howl
- Molecular Pharmacology Group, Research Institute in Healthcare Science, University of Wolverhampton, Wolverhampton WV1 1LY, UK
| | - Carmen Jerónimo
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Institute of Oncology of Porto (IPO Porto), 4200-072 Porto, Portugal; Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), 4050-513 Porto, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal.
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12
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Koloko Ngassie ML, Brandsma CA, Gosens R, Prakash YS, Burgess JK. The Stress of Lung Aging: Endoplasmic Reticulum and Senescence Tête-à-Tête. Physiology (Bethesda) 2021; 36:150-159. [PMID: 33904785 DOI: 10.1152/physiol.00039.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Beyond the structural changes, features including the dysregulation of endoplasmic reticulum (ER) stress response and increased senescence characterize the lung aging. ER stress response and senescence have been reported to be induced by factors like cigarette smoke. Therefore, deciphering the mechanisms underlying ER and senescent pathways interaction has become a challenge. In this review we highlight the known and unknown regarding ER stress response and senescence and their cross talk in aged lung.
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Affiliation(s)
- M L Koloko Ngassie
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
| | - C A Brandsma
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
| | - R Gosens
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD; University of Groningen, Department of Molecular Pharmacology, Groningen, The Netherlands
| | - Y S Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - J K Burgess
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
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13
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Féral K, Jaud M, Philippe C, Di Bella D, Pyronnet S, Rouault-Pierre K, Mazzolini L, Touriol C. ER Stress and Unfolded Protein Response in Leukemia: Friend, Foe, or Both? Biomolecules 2021; 11:biom11020199. [PMID: 33573353 PMCID: PMC7911881 DOI: 10.3390/biom11020199] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 12/15/2022] Open
Abstract
The unfolded protein response (UPR) is an evolutionarily conserved adaptive signaling pathway triggered by a stress of the endoplasmic reticulum (ER) lumen compartment, which is initiated by the accumulation of unfolded proteins. This response, mediated by three sensors-Inositol Requiring Enzyme 1 (IRE1), Activating Transcription Factor 6 (ATF6), and Protein Kinase RNA-Like Endoplasmic Reticulum Kinase (PERK)—allows restoring protein homeostasis and maintaining cell survival. UPR represents a major cytoprotective signaling network for cancer cells, which frequently experience disturbed proteostasis owing to their rapid proliferation in an usually unfavorable microenvironment. Increased basal UPR also participates in the resistance of tumor cells against chemotherapy. UPR activation also occurs during hematopoiesis, and growing evidence supports the critical cytoprotective role played by ER stress in the emergence and proliferation of leukemic cells. In case of severe or prolonged stress, pro-survival UPR may however evolve into a cell death program called terminal UPR. Interestingly, a large number of studies have revealed that the induction of proapoptotic UPR can also strongly contribute to the sensitization of leukemic cells to chemotherapy. Here, we review the current knowledge on the consequences of the deregulation of UPR signaling in leukemias and their implications for the treatment of these diseases.
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Affiliation(s)
- Kelly Féral
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
| | - Manon Jaud
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
| | - Céline Philippe
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (K.R.-P.)
| | - Doriana Di Bella
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (K.R.-P.)
| | - Stéphane Pyronnet
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
| | - Kevin Rouault-Pierre
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (K.R.-P.)
| | - Laurent Mazzolini
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- CNRS ERL5294, CRCT, F-31037 Toulouse, France
- Correspondence: (L.M.); (C.T.)
| | - Christian Touriol
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
- Correspondence: (L.M.); (C.T.)
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14
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Mendes A, Gigan JP, Rodriguez Rodrigues C, Choteau SA, Sanseau D, Barros D, Almeida C, Camosseto V, Chasson L, Paton AW, Paton JC, Argüello RJ, Lennon-Duménil AM, Gatti E, Pierre P. Proteostasis in dendritic cells is controlled by the PERK signaling axis independently of ATF4. Life Sci Alliance 2020; 4:4/2/e202000865. [PMID: 33443099 PMCID: PMC7756897 DOI: 10.26508/lsa.202000865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 12/20/2022] Open
Abstract
Differentiated dendritic cells display an unusual activation of the integrated stress response, which is necessary for normal type-I Interferon production and cell migration. In stressed cells, phosphorylation of eukaryotic initiation factor 2α (eIF2α) controls transcriptome-wide changes in mRNA translation and gene expression known as the integrated stress response. We show here that DCs are characterized by high eIF2α phosphorylation, mostly caused by the activation of the ER kinase PERK (EIF2AK3). Despite high p-eIF2α levels, DCs display active protein synthesis and no signs of a chronic integrated stress response. This biochemical specificity prevents translation arrest and expression of the transcription factor ATF4 during ER-stress induction by the subtilase cytotoxin (SubAB). PERK inactivation, increases globally protein synthesis levels and regulates IFN-β expression, while impairing LPS-stimulated DC migration. Although the loss of PERK activity does not impact DC development, the cross talk existing between actin cytoskeleton dynamics; PERK and eIF2α phosphorylation is likely important to adapt DC homeostasis to the variations imposed by the immune contexts.
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Affiliation(s)
- Andreia Mendes
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France.,Department of Medical Sciences, Institute for Research in Biomedicine (iBiMED) and Ilidio Pinho Foundation, University of Aveiro, Aveiro, Portugal.,International Associated Laboratory (LIA) CNRS "Mistra", Marseille, France
| | - Julien P Gigan
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France
| | - Christian Rodriguez Rodrigues
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France
| | - Sébastien A Choteau
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France.,Aix-Marseille Université, INSERM, Theories and Approaches of Genomic Complexity (TAGC), CENTURI, Marseille, France
| | - Doriane Sanseau
- INSERM U932, Institut Curie, ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043, Paris, France
| | - Daniela Barros
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France.,Department of Medical Sciences, Institute for Research in Biomedicine (iBiMED) and Ilidio Pinho Foundation, University of Aveiro, Aveiro, Portugal.,International Associated Laboratory (LIA) CNRS "Mistra", Marseille, France
| | - Catarina Almeida
- Department of Medical Sciences, Institute for Research in Biomedicine (iBiMED) and Ilidio Pinho Foundation, University of Aveiro, Aveiro, Portugal.,International Associated Laboratory (LIA) CNRS "Mistra", Marseille, France
| | - Voahirana Camosseto
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France.,International Associated Laboratory (LIA) CNRS "Mistra", Marseille, France.,INSERM U932, Institut Curie, ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043, Paris, France
| | - Lionel Chasson
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France
| | - Adrienne W Paton
- Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
| | - James C Paton
- Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
| | - Rafael J Argüello
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France.,INSERM U932, Institut Curie, ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043, Paris, France
| | | | - Evelina Gatti
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France .,Department of Medical Sciences, Institute for Research in Biomedicine (iBiMED) and Ilidio Pinho Foundation, University of Aveiro, Aveiro, Portugal.,International Associated Laboratory (LIA) CNRS "Mistra", Marseille, France.,INSERM U932, Institut Curie, ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043, Paris, France
| | - Philippe Pierre
- Aix Marseille Université, Centre National de la Recherch Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre d'Immunologie de Marseille Luminy (CIML), CENTURI, Marseille, France .,Department of Medical Sciences, Institute for Research in Biomedicine (iBiMED) and Ilidio Pinho Foundation, University of Aveiro, Aveiro, Portugal.,International Associated Laboratory (LIA) CNRS "Mistra", Marseille, France.,INSERM U932, Institut Curie, ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043, Paris, France
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15
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Schmidt S, Denk S, Wiegering A. Targeting Protein Synthesis in Colorectal Cancer. Cancers (Basel) 2020; 12:cancers12051298. [PMID: 32455578 PMCID: PMC7281195 DOI: 10.3390/cancers12051298] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/15/2020] [Accepted: 05/19/2020] [Indexed: 12/19/2022] Open
Abstract
Under physiological conditions, protein synthesis controls cell growth and survival and is strictly regulated. Deregulation of protein synthesis is a frequent event in cancer. The majority of mutations found in colorectal cancer (CRC), including alterations in the WNT pathway as well as activation of RAS/MAPK and PI3K/AKT and, subsequently, mTOR signaling, lead to deregulation of the translational machinery. Besides mutations in upstream signaling pathways, deregulation of global protein synthesis occurs through additional mechanisms including altered expression or activity of initiation and elongation factors (e.g., eIF4F, eIF2α/eIF2B, eEF2) as well as upregulation of components involved in ribosome biogenesis and factors that control the adaptation of translation in response to stress (e.g., GCN2). Therefore, influencing mechanisms that control mRNA translation may open a therapeutic window for CRC. Over the last decade, several potential therapeutic strategies targeting these alterations have been investigated and have shown promising results in cell lines, intestinal organoids, and mouse models. Despite these encouraging in vitro results, patients have not clinically benefited from those advances so far. In this review, we outline the mechanisms that lead to deregulated mRNA translation in CRC and highlight recent progress that has been made in developing therapeutic strategies that target these mechanisms for tumor therapy.
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Affiliation(s)
- Stefanie Schmidt
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany; (S.S.); (S.D.)
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, 97074 Würzburg, Germany
| | - Sarah Denk
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany; (S.S.); (S.D.)
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, 97074 Würzburg, Germany
| | - Armin Wiegering
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany; (S.S.); (S.D.)
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, 97074 Würzburg, Germany
- Department of Biochemistry and Molecular Biology, Comprehensive Cancer Center Mainfranken, University of Würzburg, 97074 Würzburg, Germany
- Correspondence: ; Tel.: +49-931-20138714
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16
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Chen Y, Wang H, Jiang Y, Zhang X, Wang Q. Transcriptional profiling to identify the key genes and pathways of pterygium. PeerJ 2020; 8:e9056. [PMID: 32411530 PMCID: PMC7204871 DOI: 10.7717/peerj.9056] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/03/2020] [Indexed: 12/21/2022] Open
Abstract
Purpose Pterygium results from a variety of biological pathways that are involved in the formation of ocular surface diseases. However, the exact pathogenesis of pterygium is still unclear. Our study focused on gene expression profiles to better understand the potential mechanisms of pterygium. Methods RNA sequencing experiments were performed on clinical pterygium tissues and normal conjunctival tissues. To identify the hub genes for the development of pterygium, we further conducted weighted gene co-expression network analysis (WGCNA). qRT-PCR was utilized to validate the dysregulation of the most significant differentially expressed genes (DEGs) and key hub genes in the independent subjects. Results A total of 339 DEGs (P-adjusted < 0.05 and log2 fold change [log2FC] ≥ 1.0) were obtained that reached statistical significance with p-values < 0.05. Among them, 200 DEGs were upregulated; these genes were mainly associated with the extracellular matrix and with cell adhesion or migration. In contrast, the 139 downregulated genes were enriched for endocrine and inflammation pathways. With regard to WGCNA, five modules were assigned based on the DEG profiles, and the biological functions of each module were verified with previously published GO terms. The functions included ECM-receptor interactions, the PI3K-Akt signalling pathway and an endoplasmic reticulum (ER)-related pathway. The five hub genes with the highest connectivity in each module and the five most significant DEGs showed dysregulated expression in the independent cohort samples. Conclusions RNA sequencing and WGCNA provided novel insights into the potential regulatory mechanisms of pterygium. The identified DEGs and hub genes, which were classified into two groups according to different functions or signalings, may provide important references for further research on the molecular biology of pterygium.
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Affiliation(s)
- Yihui Chen
- Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine, Shanghai, China
| | - Haoyu Wang
- Department of Dermatology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yaping Jiang
- Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaoyan Zhang
- Department of Ophthalmology, Huashan Hospital, Fudan University, Shanghai, China
| | - Qingzhong Wang
- Shanghai Key Laboratory of Compound Chinese Medicines, The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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17
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Ghadge GD, Sonobe Y, Camarena A, Drigotas C, Rigo F, Ling KK, Roos RP. Knockdown of GADD34 in neonatal mutant SOD1 mice ameliorates ALS. Neurobiol Dis 2020; 136:104702. [PMID: 31837419 DOI: 10.1016/j.nbd.2019.104702] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/26/2019] [Accepted: 12/08/2019] [Indexed: 11/19/2022] Open
Abstract
Mutations in Cu/Zn superoxide dismutase (SOD1) cause ~20% of familial ALS (FALS), which comprises 10% of total ALS cases. In mutant SOD1- (mtSOD1-) induced ALS, misfolded aggregates of SOD1 lead to activation of the unfolded protein response/integrated stress response (UPR/ISR). Protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), a kinase that phosphorylates eukaryotic translation initiator factor 2α (p-eIF2α), coordinates the response by causing a global suppression of protein synthesis. Growth arrest and DNA damage 34 (GADD34) dephosphorylates p-eIF2α, allowing protein synthesis to return to normal. If the UPR/ISR is overwhelmed by the amount of misfolded protein, CCAAT/enhancer-binding homologous protein (CHOP) is activated leading to apoptosis. In the current study we investigated the effect of knocking down CHOP and GADD34 on disease of G93A and G85R mtSOD1 mice. Although a CHOP antisense oligonucleotide had no effect on survival, an intravenous injection of GADD34 shRNA encoded in adeno-associated virus 9 (AAV9) into neonatal G93A as well as neonatal G85R mtSOD1 mice led to a significantly increased survival. G85R mtSOD1 mice had a reduction in SOD1 aggregates/load, astrocytosis, and microgliosis. In contrast, there was no change in disease phenotype when GADD34 shRNA was delivered to older G93A mtSOD1 mice. Our current study shows that GADD34 shRNA is effective in ameliorating disease when administered to neonatal mtSOD1 mice. Targeting the UPR/ISR may be beneficial in mtSOD1-induced ALS as well as other neurodegenerative diseases in which misfolded proteins and ER stress have been implicated.
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Affiliation(s)
- Ghanashyam D Ghadge
- Department of Neurology, University of Chicago Medical Center, Chicago, IL 60637, United States of America
| | - Yoshifumi Sonobe
- Department of Neurology, University of Chicago Medical Center, Chicago, IL 60637, United States of America
| | - Adrian Camarena
- Department of Neurology, University of Chicago Medical Center, Chicago, IL 60637, United States of America
| | - Claire Drigotas
- Department of Neurology, University of Chicago Medical Center, Chicago, IL 60637, United States of America
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 90201, United States of America
| | - Karen K Ling
- Ionis Pharmaceuticals, Carlsbad, CA 90201, United States of America
| | - Raymond P Roos
- Department of Neurology, University of Chicago Medical Center, Chicago, IL 60637, United States of America.
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18
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Sundaram JR, Wu Y, Lee IC, George SE, Hota M, Ghosh S, Kesavapany S, Ahmed M, Tan EK, Shenolikar S. PromISR-6, a Guanabenz Analogue, Improves Cellular Survival in an Experimental Model of Huntington's Disease. ACS Chem Neurosci 2019; 10:3575-3589. [PMID: 31313908 DOI: 10.1021/acschemneuro.9b00185] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Guanabenz (GBZ), an α2-adrenergic agonist, demonstrated off-target effects that restored protein homeostasis and ameliorated pathobiology in experimental models of neurodegenerative disease. However, GBZ did not directly activate the integrated stress response (ISR), and its proposed mode of action remains controversial. Utilizing an iterative in silico screen of over 10,000 GBZ analogues, we analyzed 432 representative compounds for cytotoxicity in Wild-type, PPP1R15A-/-, and PPP1R15B-/- mouse embryonic fibroblasts. Nine compounds clustering into three functional groups were studied in detail using cell biological and biochemical assays. Our studies demonstrated that PromISR-6 is a potent GBZ analogue that selectively activated ISR, eliciting sustained eIF2α phosphorylation. ISRIB, an ISR inhibitor, counteracted PromISR-6-mediated translational inhibition and reduction in intracellular mutant Huntingtin aggregates. Reduced protein synthesis combined with PromISR-6-stimulated autophagic clearance made PromISR-6 the most efficacious GBZ analogue to reduce Huntingtin aggregates and promote survival in a cellular model of Huntington's disease.
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Affiliation(s)
| | | | | | | | | | | | - Sashi Kesavapany
- GSK Neural Pathways Discovery Performance Unit, 11 Biopolis Way, Singapore 138667
| | - Mahmood Ahmed
- GSK Neural Pathways Discovery Performance Unit, 11 Biopolis Way, Singapore 138667
| | - Eng-King Tan
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore 308433
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19
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Michel AM, Kiniry SJ, O'Connor PBF, Mullan JP, Baranov PV. GWIPS-viz: 2018 update. Nucleic Acids Res 2019; 46:D823-D830. [PMID: 28977460 PMCID: PMC5753223 DOI: 10.1093/nar/gkx790] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 08/29/2017] [Indexed: 12/15/2022] Open
Abstract
The GWIPS-viz browser (http://gwips.ucc.ie/) is an on-line genome browser which is tailored for exploring ribosome profiling (Ribo-seq) data. Since its publication in 2014, GWIPS-viz provides Ribo-seq data for an additional 14 genomes bringing the current total to 23. The integration of new Ribo-seq data has been automated thereby increasing the number of available tracks to 1792, a 10-fold increase in the last three years. The increase is particularly substantial for data derived from human sources. Following user requests, we added the functionality to download these tracks in bigWig format. We also incorporated new types of data (e.g. TCP-seq) as well as auxiliary tracks from other sources that help with the interpretation of Ribo-seq data. Improvements in the visualization of the data have been carried out particularly for bacterial genomes where the Ribo-seq data are now shown in a strand specific manner. For higher eukaryotic datasets, we provide characteristics of individual datasets using the RUST program which includes the triplet periodicity, sequencing biases and relative inferred A-site dwell times. This information can be used for assessing the quality of Ribo-seq datasets. To improve the power of the signal, we aggregate Ribo-seq data from several studies into Global aggregate tracks for each genome.
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Affiliation(s)
- Audrey M Michel
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | | | - James P Mullan
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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20
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Samhadaneh DM, Alqarni KA, Smart A, Kuang M, Moujaber O, Maysinger D, Stochaj U. Gold nanourchins induce cellular stress, impair proteostasis and damage RNA. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2019; 22:102083. [PMID: 31404650 DOI: 10.1016/j.nano.2019.102083] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/27/2019] [Accepted: 07/31/2019] [Indexed: 12/22/2022]
Abstract
Gold nanoparticles have excellent potential for theranostic applications, but their impact on living cells is only partially understood. Many gold nanoparticles enter cells through endosomes/lysosomes which are linked to different cell organelles and compartments. Our study focuses on the unfolded protein response (UPR) in the endoplasmic reticulum (ER), cytoplasmic RNA-granules and proteostasis, because they are established indicators of cell stress and key regulators of cellular homeostasis. Using HeLa and renal proximal tubule cells as model systems, we show that gold nanourchins reduce cell proliferation, cause ER stress and impair proteostasis. Specifically, gold nanourchins activate the PERK-branch of the UPR, promote RNA oxidation, enhance P-body formation, and accumulate the oxidative stress marker Nrf2 and NFκB in nuclei. Taken together, our study demonstrates that gold nanourchins compromise ER, redox, protein, and RNA homeostasis. These insights provide new information on the cellular responses and molecular changes that gold nanourchins elicit in mammalian cells.
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Affiliation(s)
| | | | - Adam Smart
- Department of Physiology, McGill University, Montreal, Canada
| | - Mohuizi Kuang
- Department of Physiology, McGill University, Montreal, Canada
| | - Ossama Moujaber
- Department of Physiology, McGill University, Montreal, Canada
| | - Dusica Maysinger
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Ursula Stochaj
- Department of Physiology, McGill University, Montreal, Canada.
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21
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Sengupta S, Sevigny CM, Bhattacharya P, Jordan VC, Clarke R. Estrogen-Induced Apoptosis in Breast Cancers Is Phenocopied by Blocking Dephosphorylation of Eukaryotic Initiation Factor 2 Alpha (eIF2α) Protein. Mol Cancer Res 2019; 17:918-928. [DOI: 10.1158/1541-7786.mcr-18-0481] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/15/2018] [Accepted: 01/10/2019] [Indexed: 11/16/2022]
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22
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Ferreira M, Beullens M, Bollen M, Van Eynde A. Functions and therapeutic potential of protein phosphatase 1: Insights from mouse genetics. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:16-30. [PMID: 30056088 PMCID: PMC7114192 DOI: 10.1016/j.bbamcr.2018.07.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 02/07/2023]
Abstract
Protein phosphatase 1 (PP1) catalyzes more than half of all phosphoserine/threonine dephosphorylation reactions in mammalian cells. In vivo PP1 does not exist as a free catalytic subunit but is always associated with at least one regulatory PP1-interacting protein (PIP) to generate a large set of distinct holoenzymes. Each PP1 complex controls the dephosphorylation of only a small subset of PP1 substrates. We screened the literature for genetically engineered mouse models and identified models for all PP1 isoforms and 104 PIPs. PP1 itself and at least 49 PIPs were connected to human disease-associated phenotypes. Additionally, phenotypes related to 17 PIPs were clearly linked to altered PP1 function, while such information was lacking for 32 other PIPs. We propose structural reverse genetics, which combines structural characterization of proteins with mouse genetics, to identify new PP1-related therapeutic targets. The available mouse models confirm the pleiotropic action of PP1 in health and diseases.
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Affiliation(s)
- Mónica Ferreira
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium.
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Luo XH, Han B, Chen Q, Guo XT, Xie RJ, Yang T, Yang Q. Expression of PERK-eIF2α-ATF4 pathway signaling protein in the progression of hepatic fibrosis in rats. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2018; 11:3542-3550. [PMID: 31949732 PMCID: PMC6962842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 05/15/2018] [Indexed: 06/10/2023]
Abstract
OBJECTIVE This study aims to observe changes in the expression of the hepatic endoplasmic reticulum stress PERK-eIF2α-ATF4 signaling pathway protein in the progression of CCl4-induced hepatic fibrosis in rats. METHODS Male Wistar rats were sacrificed at the end of the 2nd, 4th, 8th and 12th weeks, respectively. A specific test was performed to compare the pathological changes of hepatic tissues in the model and normal groups. Immunohistochemical staining and Western blot were carried out to detect the expression of p-PERK, p-eIF2α and ATF4 proteins in the hepatic tissue group. Furthermore, real-time PCR was used to detect changes in the expression of ATF4 mRNA in hepatic tissues. RESULTS In the eight-week and twelve-week hepatic fibrosis group, significant fibrosis hyperplasia was identified in the livers of rats, and pseudo-lobules were also formed in the livers of rats in the twelve-week hepatic fibrosis group. Immunohistochemical staining and Western blot results indicated that the expression levels of p-PERK, p-eIF2α and the ATF4 protein in the livers of rats were significantly increased from the 8th week compared with the normal group (P<0.05). Real-time PCR results revealed that the expression of ATF4 mRNA was significantly increased in hepatic tissues in the hepatic fibrosis group compared with the normal group (P<0.05), and this was gradually enhanced as hepatic fibrosis progressed. CONCLUSIONS CCl4 can induce an increase in the expression of the PERK-eIF2α-ATF4 signaling protein in the development of hepatic fibrosis along with phosphorylation-mediated activation, indicating that the activation of the PERK-eIF2α-ATF4 signaling pathway may contribute to the onset and development of hepatic fibrosis by regulating downstream target genes.
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Affiliation(s)
- Xin-Hua Luo
- Department of Infectious Diseases, Guizhou People’s HospitalGuiyang, Guizhou, China
| | - Bing Han
- Department of Pathophysiology, Guizhou Medical UniversityGuiyang, Guizhou, China
| | - Qu Chen
- Department of Pathophysiology, Guizhou Medical UniversityGuiyang, Guizhou, China
| | - Xiao-Ting Guo
- Department of Pathophysiology, Guizhou Medical UniversityGuiyang, Guizhou, China
| | - Ru-Jia Xie
- Department of Pathophysiology, Guizhou Medical UniversityGuiyang, Guizhou, China
| | - Ting Yang
- Department of Pathophysiology, Guizhou Medical UniversityGuiyang, Guizhou, China
| | - Qin Yang
- Department of Pathophysiology, Guizhou Medical UniversityGuiyang, Guizhou, China
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24
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Giglio P, Gagliardi M, Tumino N, Antunes F, Smaili S, Cotella D, Santoro C, Bernardini R, Mattei M, Piacentini M, Corazzari M. PKR and GCN2 stress kinases promote an ER stress-independent eIF2α phosphorylation responsible for calreticulin exposure in melanoma cells. Oncoimmunology 2018; 7:e1466765. [PMID: 30221067 DOI: 10.1080/2162402x.2018.1466765] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 04/03/2018] [Accepted: 04/13/2018] [Indexed: 12/21/2022] Open
Abstract
The immunogenic cell death (ICD) process represents a novel therapeutic approach to treat tumours, in which cytotoxic compounds promote both cancer cell death and the emission of damage-associated molecular patterns (DAMPs) from dying cells, to activate the immune system against the malignancy. Therefore, we explored the possibility to stimulate the key molecular players with a pivotal role in the execution of the ICD program in melanoma cells. To this aim, we used the pro-ICD agents mitoxantrone and doxorubicin and found that both agents could induce cell death and stimulate the release/exposure of the strictly required DAMPs in melanoma cells: i) calreticulin (CRT) exposure on the cell membrane; ii) ATP secretion; iii) type I IFNs gene up-regulation and iv) HMGB1 secretion, highlighting no interference by oncogenic BRAF. Importantly, although the ER stress-related PERK activation has been linked to CRT externalization, through the phosphorylation of eIF2α, we found that this stress pathway together with PERK were not involved in melanoma cells. Notably, we identified PKR and GCN2 as key mediators of eIF2α phosphorylation, facilitating the translocation of CTR on melanoma cells surface, under pro-ICD drugs stimulation. Therefore, our data indicate that pro-ICD drugs are able to stimulate the production/release of DAMPs in melanoma cells at least in vitro, indicating in this approach a potential new valuable therapeutic strategy to treat human skin melanoma malignancy.
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Affiliation(s)
- Paola Giglio
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy.,Department of Epidemiology, National Institute for Infectious Diseases 'L. Spallanzani', Rome, Italy
| | - Mara Gagliardi
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy.,Department of Health Science (DISS), University of Piemonte Orientale, Novara, Italy
| | - Nicola Tumino
- Department of Epidemiology, National Institute for Infectious Diseases 'L. Spallanzani', Rome, Italy
| | - Fernanda Antunes
- Department of Pharmacology, Federal University of São Paulo, Brazil
| | - Soraya Smaili
- Department of Pharmacology, Federal University of São Paulo, Brazil
| | - Diego Cotella
- Department of Health Science (DISS), University of Piemonte Orientale, Novara, Italy
| | - Claudio Santoro
- Department of Health Science (DISS), University of Piemonte Orientale, Novara, Italy
| | - Roberta Bernardini
- Department of Biology, Centro Servizi Interdipartimentale-STA, University of Rome Tor Vergata, Rome, Italy
| | - Maurizio Mattei
- Department of Biology, Centro Servizi Interdipartimentale-STA, University of Rome Tor Vergata, Rome, Italy
| | - Mauro Piacentini
- Department of Biology, University of Rome 'Tor Vergata', Rome, Italy.,Department of Epidemiology, National Institute for Infectious Diseases 'L. Spallanzani', Rome, Italy
| | - Marco Corazzari
- Department of Epidemiology, National Institute for Infectious Diseases 'L. Spallanzani', Rome, Italy.,Department of Health Science (DISS), University of Piemonte Orientale, Novara, Italy
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25
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Paolini NA, Moore KS, di Summa FM, Fokkema IFAC, ‘t Hoen PAC, von Lindern M. Ribosome profiling uncovers selective mRNA translation associated with eIF2 phosphorylation in erythroid progenitors. PLoS One 2018; 13:e0193790. [PMID: 29634759 PMCID: PMC5892948 DOI: 10.1371/journal.pone.0193790] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/17/2018] [Indexed: 11/18/2022] Open
Abstract
The regulation of translation initiation factor 2 (eIF2) is important for erythroid survival and differentiation. Lack of iron, a critical component of heme and hemoglobin, activates Heme Regulated Inhibitor (HRI). This results in phosphorylation of eIF2 and reduced eIF2 availability, which inhibits protein synthesis. Translation of specific transcripts such as Atf4, however, is enhanced. Upstream open reading frames (uORFs) are key to this regulation. The aim of this study is to investigate how tunicamycin treatment, that induces eIF2 phosphorylation, affects mRNA translation in erythroblasts. Ribosome profiling combined with RNA sequencing was used to determine translation initiation sites and ribosome density on individual transcripts. Treatment of erythroblasts with Tunicamycin (Tm) increased phosphorylation of eIF2 2-fold. At a false discovery rate of 1%, ribosome density was increased for 147 transcripts, among which transcriptional regulators such as Atf4, Tis7/Ifrd1, Pnrc2, Gtf2h, Mbd3, JunB and Kmt2e. Translation of 337 transcripts decreased more than average, among which Dym and Csde1. Ribosome profiling following Harringtonine treatment uncovered novel translation initiation sites and uORFs. Surprisingly, translated uORFs did not predict the sensitivity of transcripts to altered ribosome recruitment in presence or absence of Tm. The regulation of transcription and translation factors in reponse to eIF2 phosphorylation may explain the large overall response to iron deficiency in erythroblasts.
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Affiliation(s)
- Nahuel A. Paolini
- Department of Hematopoiesis, Sanquin Research, and Landsteiner Laboratory AMC/UvA, Amsterdam, The Netherlands
| | - Kat S. Moore
- Department of Hematopoiesis, Sanquin Research, and Landsteiner Laboratory AMC/UvA, Amsterdam, The Netherlands
| | - Franca M. di Summa
- Department of Hematopoiesis, Sanquin Research, and Landsteiner Laboratory AMC/UvA, Amsterdam, The Netherlands
| | - Ivo F. A. C. Fokkema
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter A. C. ‘t Hoen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marieke von Lindern
- Department of Hematopoiesis, Sanquin Research, and Landsteiner Laboratory AMC/UvA, Amsterdam, The Netherlands
- * E-mail:
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26
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Meng W, Han SC, Li CC, Dong HJ, Wang XJ. Multifunctional viral protein γ34.5 manipulates nucleolar protein NOP53 for optimal viral replication of HSV-1. Cell Death Dis 2018; 9:103. [PMID: 29367603 PMCID: PMC5833762 DOI: 10.1038/s41419-017-0116-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 12/14/2022]
Abstract
To ensure efficient virus replication, herpes simplex virus type 1 (HSV-1) encodes several viral proteins to counter host defense response upon infection. Among these proteins, the multifunctional viral protein γ34.5 crucially interferes with or disrupts several antiviral pathways at multiple levels. The current study shows that γ34.5 utilizes nucleolar protein NOP53 to facilitate the dephosphorylation of eukaryotic initiation factor eIF2α for efficient viral translation. Our study shows that: (1) ectopic expression of NOP53 greatly increases the intracellular and extracellular viral yields of HSV-1 (wild strain F) in type I interferon-deficient Vero cells, and more subtly promotes viral replication of γ34.5 deletion mutant virus HSV-1/Δγ34.5. (2) NOP53 is migrated from nuclei in HSV-1/F infected cells, but is redistributed incompletely after infection by either HSV-1/Δγ34.5 or ICP4 deletion mutant virus HSV-1/d120 (replication inadequate). Ectopic expression of γ34.5, consequently, induces cytoplasmic translocation of NOP53 in response to HSV-1/Δγ34.5 infection. (3) Increase of NOP53, in two forms of transient transfection and in vitro expression, attenuates the phosphorylation level of eIF2α in HSV-1/F infected cells, but fails to affect eIF2α phosphorylation induced by HSV-1/Δγ34.5 infection. (4) Knockdown of NOP53, which impairs the specific interaction between γ34.5 and protein phosphatase PP1α, disrupts the ability of γ34.5 to maintain HSV-1 virulence. (5) NOP53 knockdown also significantly reduces tissue damage and decreases viral yield in livers of HSV-1 infected mice. Our findings expand the understanding of the underlying mechanism by which viral protein γ34.5 induces NOP53 redistribution; cytoplasmic NOP53 facilitates γ34.5 recruitment of PP1α to dephosphorylate eIF2α, for optimal viral replication. This paper also demonstrates that blocking the specific interaction between γ34.5 and PP1α would be a useful approach for the development of antiviral agents.
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Affiliation(s)
- Wen Meng
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, China
| | - Shi-Chong Han
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, China
| | - Cui-Cui Li
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, China
| | - Hui-Jun Dong
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, China
| | - Xiao-Jia Wang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, 100193, Beijing, China.
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27
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Goh CW, Lee IC, Sundaram JR, George SE, Yusoff P, Brush MH, Sze NSK, Shenolikar S. Chronic oxidative stress promotes GADD34-mediated phosphorylation of the TAR DNA-binding protein TDP-43, a modification linked to neurodegeneration. J Biol Chem 2017; 293:163-176. [PMID: 29109149 DOI: 10.1074/jbc.m117.814111] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/01/2017] [Indexed: 12/28/2022] Open
Abstract
Oxidative and endoplasmic reticulum (ER) stresses are hallmarks of the pathophysiology of ALS and other neurodegenerative diseases. In these stresses, different kinases phosphorylate eukaryotic initiation factor eIF2α, enabling the translation of stress response genes; among these is GADD34, the protein product of which recruits the α-isoform of protein phosphatase 1 catalytic subunit (PP1α) and eIF2α to assemble a phosphatase complex catalyzing eIF2α dephosphorylation and resumption of protein synthesis. Aberrations in this pathway underlie the aforementioned disorders. Previous observations indicating that GADD34 is induced by arsenite, a thiol-directed oxidative stressor, in the absence of eIF2α phosphorylation suggest other roles for GADD34. Here, we report that arsenite-induced oxidative stress differs from thapsigargin- or tunicamycin-induced ER stress in promoting GADD34 transcription and the preferential translation of its mRNA in the absence of eIF2α phosphorylation. Arsenite also stabilized GADD34 protein, slowing its degradation. In response to oxidative stress, but not ER stress, GADD34 recruited TDP-43, and enhanced cytoplasmic distribution and cysteine modifications of TDP-43 promoted its binding to GADD34. Arsenite also recruited a TDP-43 kinase, casein kinase-1ϵ (CK1ϵ), to GADD34. Concomitant with TDP-43 aggregation and proteolysis after prolonged arsenite exposure, GADD34-bound CK1ϵ catalyzed TDP-43 phosphorylations at serines 409/410, which were diminished or absent in GADD34-/- cells. Our findings highlight that the phosphatase regulator, GADD34, also functions as a kinase scaffold in response to chronic oxidative stress and recruits CK1ϵ and oxidized TDP-43 to facilitate its phosphorylation, as seen in TDP-43 proteinopathies.
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Affiliation(s)
- Catherine Wenhui Goh
- Signature Research Programs in Neuroscience and Behavioural Disorders, Singapore 169857, Singapore
| | - Irene Chengjie Lee
- Signature Research Programs in Neuroscience and Behavioural Disorders, Singapore 169857, Singapore; Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Jeyapriya Rajameenakshi Sundaram
- Signature Research Programs in Neuroscience and Behavioural Disorders, Singapore 169857, Singapore; Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Simi Elizabeth George
- Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Permeen Yusoff
- Signature Research Programs in Neuroscience and Behavioural Disorders, Singapore 169857, Singapore; Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Matthew Hayden Brush
- Ontology Development group, Oregon Health and Science University, Portland, Oregon 97239
| | - Newman Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore
| | - Shirish Shenolikar
- Signature Research Programs in Neuroscience and Behavioural Disorders, Singapore 169857, Singapore; Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Psychiatry and Behavioral Sciences and Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710.
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28
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Oxidative stress promotes SIRT1 recruitment to the GADD34/PP1α complex to activate its deacetylase function. Cell Death Differ 2017; 25:255-267. [PMID: 28984870 DOI: 10.1038/cdd.2017.152] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/01/2017] [Accepted: 08/15/2017] [Indexed: 12/20/2022] Open
Abstract
Phosphorylation of the eukaryotic translation initiation factor, eIF2α, by stress-activated protein kinases and dephosphorylation by the growth arrest and DNA damage-inducible protein (GADD34)-containing phosphatase is a central node in the integrated stress response. Mass spectrometry demonstrated GADD34 acetylation at multiple lysines. Substituting K315 and K322 with alanines or glutamines did not impair GADD34's ability to recruit protein phosphatase 1α (PP1α) or eIF2α, suggesting that GADD34 acetylation did not modulate eIF2α phosphatase activity. Arsenite (Ars)-induced oxidative stress increased cellular GADD34 levels and enhanced Sirtuin 1 (SIRT1) recruitment to assemble a cytoplasmic complex containing GADD34, PP1α, eIF2α and SIRT1. Induction of GADD34 in WT MEFs paralleled the dephosphorylation of eIF2α (phosphoserine-51) and SIRT1 (phosphoserine-47). By comparison, eIF2α and SIRT1 were persistently phosphorylated in Ars-treated GADD34-/- MEFs. Expressing WT GADD34, but not a mutant unable to bind PP1α in GADD34-/- MEFs restored both eIF2α and SIRT1 dephosphorylation. SIRT1 dephosphorylation increased its deacetylase activity, measured in vitro and in cells. Loss of function of GADD34 or SIRT1 enhanced cellular p-eIF2α levels and attenuated cell death following Ars exposure. These results highlighted a novel role for the GADD34/PP1α complex in coordinating the dephosphorylation and reactivation of eIF2α and SIRT1 to determine cell fate following oxidative stress.
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29
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Translating protein phosphatase research into treatments for neurodegenerative diseases. Biochem Soc Trans 2017; 45:101-112. [PMID: 28202663 DOI: 10.1042/bst20160157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 12/11/2022]
Abstract
Many of the major neurodegenerative disorders are characterized by the accumulation of intracellular protein aggregates in neurons and other cells in brain, suggesting that errors in protein quality control mechanisms associated with the aging process play a critical role in the onset and progression of disease. The increased understanding of the unfolded protein response (UPR) signaling network and, more specifically, the structure and function of eIF2α phosphatases has enabled the development or discovery of small molecule inhibitors that show great promise in restoring protein homeostasis and ameliorating neuronal damage and death. While this review focuses attention on one or more eIF2α phosphatases, the wide range of UPR proteins that are currently being explored as potential drug targets bodes well for the successful future development of therapies to preserve neuronal function and treat neurodegenerative disease.
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30
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Chronically stressed or stress-preconditioned neurons fail to maintain stress granule assembly. Cell Death Dis 2017; 8:e2788. [PMID: 28492545 PMCID: PMC5520719 DOI: 10.1038/cddis.2017.199] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 03/31/2017] [Accepted: 05/04/2017] [Indexed: 12/18/2022]
Abstract
Dysregulation of stress granules (SGs) and their resident proteins contributes to pathogenesis of a number of (neuro)degenerative diseases. Phosphorylation of eIF2α is an event integrating different types of cellular stress and it is required for SG assembly. Phosphorylated eIF2α (p-eIF2α) is upregulated in the nervous system in some neurodegenerative conditions. We found that increasing p-eIF2α level by proteasomal inhibition in cultured cells, including mouse and human neurons, before a SG-inducing stress ('stress preconditioning'), limits their ability to maintain SG assembly. This is due to upregulation of PP1 phosphatase regulatory subunits GADD34 and/or CReP in preconditioned cells and early decline of p-eIF2α levels during subsequent acute stress. In two model systems with constitutively upregulated p-eIF2α, mouse embryonic fibroblasts lacking CReP and brain neurons of tau transgenic mice, SG formation was also impaired. Thus, neurons enduring chronic stress or primed by a transient mild stress fail to maintain p-eIF2α levels following subsequent acute stress, which would compromise protective function of SGs. Our findings provide experimental evidence on possible loss of function for SGs in certain neurodegenerative diseases.
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31
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Crespillo-Casado A, Chambers JE, Fischer PM, Marciniak SJ, Ron D. PPP1R15A-mediated dephosphorylation of eIF2α is unaffected by Sephin1 or Guanabenz. eLife 2017; 6. [PMID: 28447936 PMCID: PMC5429092 DOI: 10.7554/elife.26109] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 04/21/2017] [Indexed: 12/18/2022] Open
Abstract
Dephosphorylation of translation initiation factor 2 (eIF2α) terminates signalling in the mammalian integrated stress response (ISR) and has emerged as a promising target for modifying the course of protein misfolding diseases. The [(o-chlorobenzylidene)amino]guanidines (Guanabenz and Sephin1) have been proposed to exert protective effects against misfolding by interfering with eIF2α-P dephosphorylation through selective disruption of a PP1-PPP1R15A holophosphatase complex. Surprisingly, they proved inert in vitro affecting neither stability of the PP1-PPP1R15A complex nor substrate-specific dephosphorylation. Furthermore, eIF2α-P dephosphorylation, assessed by a kinase shut-off experiment, progressed normally in Sephin1-treated cells. Consistent with its role in defending proteostasis, Sephin1 attenuated the IRE1 branch of the endoplasmic reticulum unfolded protein response. However, repression was noted in both wildtype and Ppp1r15a deleted cells and in cells rendered ISR-deficient by CRISPR editing of the Eif2s1 locus to encode a non-phosphorylatable eIF2α (eIF2αS51A). These findings challenge the view that [(o-chlorobenzylidene)amino]guanidines restore proteostasis by interfering with eIF2α-P dephosphorylation.
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Affiliation(s)
- Ana Crespillo-Casado
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Joseph E Chambers
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Peter M Fischer
- Division of Biomolecular Science and Medicinal Chemistry, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom.,Centre for Biomolecular Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - David Ron
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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