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Oh-Hashi K, Takahashi K, Hirata Y. Regulation of the ER-bound transcription factor Luman/CREB3 in HEK293 cells. FEBS Lett 2019; 593:2771-2778. [PMID: 31291699 DOI: 10.1002/1873-3468.13535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 11/07/2022]
Abstract
CREB3 is a transcription factor localized to the ER. Here, we investigated endogenous CREB3 expression in HEK293 cells using pharmacological and genome editing approaches. Full-length CREB3 detected under resting conditions disappeared following treatment with tunicamycin, brefeldin A and nigericin. Treatment with cycloheximide and MG132 indicated that endogenous CREB3 is a proteasome substrate. Using cells deficient for the ER-associated protein degradation (ERAD) factors SEL1L and Herp, we demonstrate that SEL1L, but not Herp, plays a crucial role in the posttranslational regulation of full-length CREB3 expression. In addition, kifunensine, an α-mannosidase inhibitor, remarkably increased full-length CREB3 expression. Our study suggests that endogenous full-length CREB3 is a novel substrate for ERAD and identifies unique cellular signals distinct from those in canonical ER stress.
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Affiliation(s)
- Kentaro Oh-Hashi
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Japan
- Graduate School of Natural Science and Technology, Gifu University, Japan
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Japan
| | - Kanto Takahashi
- Graduate School of Natural Science and Technology, Gifu University, Japan
| | - Yoko Hirata
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Japan
- Graduate School of Natural Science and Technology, Gifu University, Japan
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Japan
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52
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Hetz C, Axten JM, Patterson JB. Pharmacological targeting of the unfolded protein response for disease intervention. Nat Chem Biol 2019; 15:764-775. [PMID: 31320759 DOI: 10.1038/s41589-019-0326-2] [Citation(s) in RCA: 177] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/17/2019] [Indexed: 02/07/2023]
Abstract
Accumulation of unfolded proteins at the endoplasmic reticulum (ER) is a salient attribute of many human diseases including obesity, liver disorders, cancer, diabetes and neurodegeneration. To restore ER proteostasis, cells activate the unfolded protein response (UPR), a signaling pathway that imposes adaptive programs or triggers apoptosis of damaged cells. The UPR is critical to sustain the normal function of specialized secretory cells (i.e., pancreatic β cells and B lymphocytes) and to control the production of lipids and cholesterol in the liver. In the context of disease, adaptive UPR responses have been linked to the growth of solid tumors, whereas chronic ER stress contributes to cell dysfunction in brain diseases, metabolic syndromes, among other conditions. Here we discuss recent developments in the design and optimization of novel compounds to manipulate UPR signaling and their efficacy in various disease models.
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Affiliation(s)
- Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. .,FONDAP Center for Geroscience, Brain Health and Metabolism, Santiago, Chile. .,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile. .,Buck Institute for Research on Aging, Novato, CA, USA. .,Department of Immunology and Infectious diseases, Harvard School of Public Health, Boston, MA, USA.
| | - Jeffrey M Axten
- Medicinal Chemistry, Medicine Design, GlaxoSmithKline, Collegeville, PA, USA.
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Khan HA, Margulies CE. The Role of Mammalian Creb3-Like Transcription Factors in Response to Nutrients. Front Genet 2019; 10:591. [PMID: 31293620 PMCID: PMC6598459 DOI: 10.3389/fgene.2019.00591] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 06/04/2019] [Indexed: 12/18/2022] Open
Abstract
Our ability to overcome the challenges behind metabolic disorders will require a detailed understanding of the regulation of responses to nutrition. The Creb3 transcription factor family appears to have a unique regulatory role that links cellular secretory capacity with development, nutritional state, infection, and other stresses. This role in regulating individual secretory capacity genes could place this family of transcription factors at an important regulatory intersection mediating an animal’s responses to nutrients and other environmental challenges. Interestingly, in both humans and mice, individuals with mutations in Creb3L3/CrebH, one of the Creb3 family members, exhibit hypertriglyceridemia (HTG) thus linking this transcription factor to lipid metabolism. We are beginning to understand how Creb3L3 and related family members are regulated and to dissect the potential redundancy and cross talk between distinct family members, thereby mediating both healthy and pathological responses to the environment. Here, we review the current knowledge on the regulation of Creb3 family transcription factor activity, their target genes, and their role in metabolic disease.
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Affiliation(s)
- Haris A Khan
- Physiological Chemistry, Biomedical Center, Ludwig-Maximilians-Universität, Munich, Germany
| | - Carla E Margulies
- Physiological Chemistry, Biomedical Center, Ludwig-Maximilians-Universität, Munich, Germany
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Wu S, Ma S, Yin X, Yi P, Liu J. An integrated PKD1-dependent signaling network amplifies IRE1 prosurvival signaling. J Biol Chem 2019; 294:11119-11130. [PMID: 31167779 DOI: 10.1074/jbc.ra118.003311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 03/21/2019] [Indexed: 12/13/2022] Open
Abstract
Following the accumulation of improperly folded proteins in the endoplasmic reticulum (ER), a condition known as ER stress in this compartment triggers an adaptive signaling pathway referred to as the unfolded protein response (UPR). The UPR aims at restoring ER homeostasis; if the ER stress cannot be resolved, apoptosis is triggered. However, the mechanisms responsible for regulating the balance between cell life and death decisions that occur after exposure to ER stress remain unclear. Protein kinase D1 (PKD1) has been reported to initiate protective signaling against oxidative stress or ischemia, two conditions that impinge on the induction of ER stress. In addition, the high levels of expression of PKD1, observed in highly proliferative cancers and tumors with poor prognosis, contribute to enhanced resistance to chemotherapy. In this study, we show that the ER stress inducers tunicamycin and thapsigargin lead to the activation of PKD1 in human prostate cancer PC-3 cells and in hepatoma HepG2 cells through a PKCδ-dependent mechanism. Moreover, our data indicate that PKD1 is required for the stabilization of inositol-requiring enzyme 1 (IRE1) and the subsequent regulation of its activity. PKD1 activation contributes to the phosphorylation of mitogen-activated protein kinase phosphatase 1, resulting in decreased IRE1-mediated c-Jun N-terminal kinase activation. This study unveils the existence of a novel PKD1-dependent prosurvival mechanism that is activated upon ER stress and selectively enhances IRE1 prosurvival signaling.
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Affiliation(s)
- Shiyong Wu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei, China
| | - Shumin Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei, China
| | - Xueliang Yin
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei, China
| | - Ping Yi
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei, China
| | - Jianfeng Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei, China
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Abstract
Liver fibrosis (LF) is known as a result of the progressive accumulation of extracellular matrix (ECM), and always ascribed to chronic liver diseases. Advanced liver fibrosis results in cirrhosis, liver failure, portal hypertension, and even multi-organ dysfunction and will bring up a health care burden worldwide. Cyclic AMP response-element binding protein (CREB), as a critical transcriptional factor, binds with conserved cAMP response-element (CRE), which is located in the promoter of targeted genes, to regulate the transcription. In the past decades, numerous studies have contributed to improved understanding of the links between CREB and liver fibrosis. In this review, we will summarize molecular mechanisms of CREB pathways and discuss contributions of CREB to liver fibrosis, focusing on activation and proliferation of hepatic stellate cells (HSCs), proliferation of cholangiocytes, deposition of extracellular matrix (ECM) and inflammation, for the development of antifibrotic therapies.
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Affiliation(s)
- Guixin Li
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Qianqian Jiang
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Keshu Xu
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Glembotski CC, Rosarda JD, Wiseman RL. Proteostasis and Beyond: ATF6 in Ischemic Disease. Trends Mol Med 2019; 25:538-550. [PMID: 31078432 DOI: 10.1016/j.molmed.2019.03.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/16/2019] [Accepted: 03/25/2019] [Indexed: 12/28/2022]
Abstract
Endoplasmic reticulum (ER) stress is a pathological hallmark of numerous ischemic diseases, including stroke and myocardial infarction (MI). In these diseases, ER stress leads to activation of the unfolded protein response (UPR) and subsequent adaptation of cellular physiology in ways that dictate cellular fate following ischemia. Recent evidence highlights a protective role for the activating transcription factor 6 (ATF6) arm of the UPR in mitigating adverse outcomes associated with ischemia/reperfusion (I/R) injury in multiple disease models. This suggests ATF6 as a potential therapeutic target for intervening in diverse ischemia-related disorders. Here, we discuss the evidence demonstrating the importance of ATF6 signaling in protecting different tissues against ischemic damage and discuss preclinical results focused on defining the potential for pharmacologically targeting ATF6 to intervene in such diseases.
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Affiliation(s)
- Christopher C Glembotski
- San Diego State University Heart Institute and the Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Jessica D Rosarda
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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57
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Borkham-Kamphorst E, Van de Leur E, Haas U, Weiskirchen R. Liver parenchymal cells lacking Lipocalin 2 (LCN2) are prone to endoplasmic reticulum stress and unfolded protein response. Cell Signal 2019; 55:90-99. [PMID: 30615971 DOI: 10.1016/j.cellsig.2019.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 01/16/2023]
Abstract
Unfolded protein response (UPR) is an adaptive mechanism allowing the endoplasmic reticulum (ER) to react to an accumulation of unfolded proteins in its lumen, also known as ER stress. The UPR is interconnected with inflammation through several pathways such as reactive oxygen species (ROS) production resulting from the protein folding or alternatively, activation of nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) via IRE1, or induction of acute phase response (APR). Lipocalin 2 (LCN2) is one of the APR proteins induced under inflammatory conditions and up-regulated during ER stress. Upon incubation of Lcn2-/- and wild type (wt) primary hepatocytes with tunicamycin (TM) or thapsigargin (TG) we found the Lcn2-/- hepatocytes to react with strong UPR to the ER stress, as evidenced by significantly increased levels of Grp94, Bip and Chop mRNA and protein compared to the wt. TM and TG-treated hepatocytes activated p65 NF-κB and JNK, the pathways that respond to stress stimuli and playing a central role in inflammation and apoptosis, respectively. ER stress further activated and cleaved full-length CREBH/CREB3L3, the hepatocyte specific transcription factor to induce systemic inflammatory responses. Upregulation of the C/EBP homologous protein (CHOP) was very prominent in Lcn2-/- hepatocytes and sustained until 48 h, resulting in hepatocyte apoptosis as evidenced by increased cleaved caspase 3. We also explored the UPR of the Lcn2 null mouse livers in acute intoxication and inflammation stages with a single application of lipopolysaccharide (LPS) or carbon tetrachloride (CCl4). The Lcn2 null mice clearly developed stronger UPR in LPS- and CCl4-induced ER stress compared to the wt. Our findings indicate that the upregulation of LCN2 during ER stress-induced inflammatory responses protects hepatocytes from being overwhelmed by UPR upon liver injury.
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Affiliation(s)
- Erawan Borkham-Kamphorst
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Germany.
| | - Eddy Van de Leur
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Germany
| | - Ute Haas
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Germany.
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58
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Hossain MM, Sivaram G, Richardson JR. Regional Susceptibility to ER Stress and Protection by Salubrinal Following a Single Exposure to Deltamethrin. Toxicol Sci 2019; 167:249-257. [PMID: 30247739 PMCID: PMC6317433 DOI: 10.1093/toxsci/kfy238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Endoplasmic reticulum (ER) stress is a significant contributor to neurodegeneration and cognitive dysfunction. Recently, we reported that repeated exposure to the pyrethroid insecticide deltamethrin caused ER stress in the hippocampus of adult mice, which was accompanied by deficits in learning (Hossain et al., 2015). Here, we investigated regional susceptibility to ER stress and the ability of salubrinal, an inhibitor of ER stress, to reduce apoptosis following a single oral administration of deltamethrin (6 mg/kg). Deltamethrin significantly increased the ER stress marker C/EBP-homologous protein (CHOP) in the hippocampus by 148% at 24 and 48 h compared with age-matched controls. In contrast, CHOP was increased by 146% in the frontal cortex only at 48 h after deltamethrin exposure. Similarly, the level of GRP-78 was increased by 314% and 262% in the hippocampus at 24 and 48 h, whereas the same factors were increased by 178% at 24 h and 139% at 48 h in the frontal cortex. These changes were accompanied by increased levels of activated caspase-12, caspase-3, and TUNEL-positive cells in both brain regions, with the hippocampus showing a more robust response. Pre-treatment of mice with the eIf2α inhibitor salubrinal prevented deltamethrin-induced caspase-3 activation and attenuated the number of TUNEL-positive cells. These data demonstrate that the hippocampus appears to be particularly vulnerable to deltamethrin exposure in adult animals, which may contribute to observed effects of deltamethrin on cognitive function.
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Affiliation(s)
- Muhammad M Hossain
- Department of Pharmaceutical Sciences and Center for Neurodegenerative Disease and Aging, Northeast Ohio Medical University, Rootstown, Ohio 44272
- Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, Florida 33199
| | - Ganeshraj Sivaram
- Department of Pharmaceutical Sciences and Center for Neurodegenerative Disease and Aging, Northeast Ohio Medical University, Rootstown, Ohio 44272
| | - Jason R Richardson
- Department of Pharmaceutical Sciences and Center for Neurodegenerative Disease and Aging, Northeast Ohio Medical University, Rootstown, Ohio 44272
- Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, Florida 33199
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Almanza A, Carlesso A, Chintha C, Creedican S, Doultsinos D, Leuzzi B, Luís A, McCarthy N, Montibeller L, More S, Papaioannou A, Püschel F, Sassano ML, Skoko J, Agostinis P, de Belleroche J, Eriksson LA, Fulda S, Gorman AM, Healy S, Kozlov A, Muñoz‐Pinedo C, Rehm M, Chevet E, Samali A. Endoplasmic reticulum stress signalling - from basic mechanisms to clinical applications. FEBS J 2019; 286:241-278. [PMID: 30027602 PMCID: PMC7379631 DOI: 10.1111/febs.14608] [Citation(s) in RCA: 566] [Impact Index Per Article: 113.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/24/2018] [Accepted: 07/18/2018] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is a membranous intracellular organelle and the first compartment of the secretory pathway. As such, the ER contributes to the production and folding of approximately one-third of cellular proteins, and is thus inextricably linked to the maintenance of cellular homeostasis and the fine balance between health and disease. Specific ER stress signalling pathways, collectively known as the unfolded protein response (UPR), are required for maintaining ER homeostasis. The UPR is triggered when ER protein folding capacity is overwhelmed by cellular demand and the UPR initially aims to restore ER homeostasis and normal cellular functions. However, if this fails, then the UPR triggers cell death. In this review, we provide a UPR signalling-centric view of ER functions, from the ER's discovery to the latest advancements in the understanding of ER and UPR biology. Our review provides a synthesis of intracellular ER signalling revolving around proteostasis and the UPR, its impact on other organelles and cellular behaviour, its multifaceted and dynamic response to stress and its role in physiology, before finally exploring the potential exploitation of this knowledge to tackle unresolved biological questions and address unmet biomedical needs. Thus, we provide an integrated and global view of existing literature on ER signalling pathways and their use for therapeutic purposes.
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Affiliation(s)
- Aitor Almanza
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | - Antonio Carlesso
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGöteborgSweden
| | - Chetan Chintha
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | | | - Dimitrios Doultsinos
- INSERM U1242University of RennesFrance
- Centre de Lutte Contre le Cancer Eugène MarquisRennesFrance
| | - Brian Leuzzi
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | - Andreia Luís
- Ludwig Boltzmann Institute for Experimental and Clinical TraumatologyAUVA Research CentreViennaAustria
| | - Nicole McCarthy
- Institute for Experimental Cancer Research in PaediatricsGoethe‐UniversityFrankfurtGermany
| | - Luigi Montibeller
- Neurogenetics GroupDivision of Brain SciencesFaculty of MedicineImperial College LondonUK
| | - Sanket More
- Department Cellular and Molecular MedicineLaboratory of Cell Death and TherapyKU LeuvenBelgium
| | - Alexandra Papaioannou
- INSERM U1242University of RennesFrance
- Centre de Lutte Contre le Cancer Eugène MarquisRennesFrance
| | - Franziska Püschel
- Cell Death Regulation GroupOncobell ProgramBellvitge Biomedical Research Institute (IDIBELL)BarcelonaSpain
| | - Maria Livia Sassano
- Department Cellular and Molecular MedicineLaboratory of Cell Death and TherapyKU LeuvenBelgium
| | - Josip Skoko
- Institute of Cell Biology and ImmunologyUniversity of StuttgartGermany
| | - Patrizia Agostinis
- Department Cellular and Molecular MedicineLaboratory of Cell Death and TherapyKU LeuvenBelgium
| | - Jackie de Belleroche
- Neurogenetics GroupDivision of Brain SciencesFaculty of MedicineImperial College LondonUK
| | - Leif A. Eriksson
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGöteborgSweden
| | - Simone Fulda
- Institute for Experimental Cancer Research in PaediatricsGoethe‐UniversityFrankfurtGermany
| | | | - Sandra Healy
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | - Andrey Kozlov
- Ludwig Boltzmann Institute for Experimental and Clinical TraumatologyAUVA Research CentreViennaAustria
| | - Cristina Muñoz‐Pinedo
- Cell Death Regulation GroupOncobell ProgramBellvitge Biomedical Research Institute (IDIBELL)BarcelonaSpain
| | - Markus Rehm
- Institute of Cell Biology and ImmunologyUniversity of StuttgartGermany
| | - Eric Chevet
- INSERM U1242University of RennesFrance
- Centre de Lutte Contre le Cancer Eugène MarquisRennesFrance
| | - Afshin Samali
- Apoptosis Research CentreNational University of IrelandGalwayIreland
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60
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Mitochondria, Oxytocin, and Vasopressin: Unfolding the Inflammatory Protein Response. Neurotox Res 2018; 36:239-256. [PMID: 30259418 DOI: 10.1007/s12640-018-9962-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 09/11/2018] [Accepted: 09/17/2018] [Indexed: 01/07/2023]
Abstract
Neuroendocrine and immune signaling pathways are activated following insults such as stress, injury, and infection, in a systemic response aimed at restoring homeostasis. Mitochondrial metabolism and function have been implicated in the control of immune responses. Commonly studied along with mitochondrial function, reactive oxygen species (ROS) are closely linked to cellular inflammatory responses. It is also accepted that cells experiencing mitochondrial or endoplasmic reticulum (ER) stress induce response pathways in order to cope with protein-folding dysregulation, in homeostatic responses referred to as the unfolded protein responses (UPRs). Recent reports indicate that the UPRs may play an important role in immune responses. Notably, the homeostasis-regulating hormones oxytocin (OXT) and vasopressin (AVP) are also associated with the regulation of inflammatory responses and immune function. Intriguingly, OXT and AVP have been linked with ER unfolded protein responses (UPRER), and can impact ROS production and mitochondrial function. Here, we will review the evidence for interactions between these various factors and how these neuropeptides might influence mitochondrial processes.
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61
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Al-Maskari M, Care MA, Robinson E, Cocco M, Tooze RM, Doody GM. Site-1 protease function is essential for the generation of antibody secreting cells and reprogramming for secretory activity. Sci Rep 2018; 8:14338. [PMID: 30254311 PMCID: PMC6156501 DOI: 10.1038/s41598-018-32705-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 09/11/2018] [Indexed: 01/08/2023] Open
Abstract
The unfolded protein response (UPR) and activation of XBP1 is necessary for high secretory efficiency and functional differentiation of antibody secreting cells (ASCs). The UPR additionally includes a branch in which membrane-bound transcription factors, exemplified by ATF6, undergo intramembrane-proteolysis by the sequential action of site-1 (MBTPS1/S1P) and site-2 proteases (MBTPS2/S2P) and release of the cytoplasmic domain as an active transcription factor. Such regulation is shared with a family of CREB3-related transcription factors and sterol regulatory element-binding proteins (SREBPs). Of these, we identify that the CREB3 family member CREB3L2 is strongly induced and activated during the transition from B-cell to plasma cell state. Inhibition of site-1 protease leads to a profound reduction in plasmablast number linked to induction of autophagy. Plasmablasts generated in the presence of site-1 protease inhibitor segregated into CD38high and CD38low populations, the latter characterized by a marked reduction in the capacity to secrete IgG. Site-1 protease inhibition is accompanied by a distinctive change in gene expression associated with amino acid, steroid and fatty acid synthesis pathways. These results demonstrate that transcriptional control of metabolic programs necessary for secretory activity can be targeted via site-1 protease inhibition during ASC differentiation.
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Affiliation(s)
- Muna Al-Maskari
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, LS9 7TF, United Kingdom
| | - Matthew A Care
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, LS9 7TF, United Kingdom
- Bioinformatics Group, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Emily Robinson
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, LS9 7TF, United Kingdom
| | - Mario Cocco
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, LS9 7TF, United Kingdom
| | - Reuben M Tooze
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, LS9 7TF, United Kingdom
| | - Gina M Doody
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, LS9 7TF, United Kingdom.
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62
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A PDX1-ATF transcriptional complex governs β cell survival during stress. Mol Metab 2018; 17:39-48. [PMID: 30174228 PMCID: PMC6197747 DOI: 10.1016/j.molmet.2018.07.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/13/2018] [Accepted: 07/23/2018] [Indexed: 01/05/2023] Open
Abstract
Objective Loss of insulin secretion due to failure or death of the insulin secreting β cells is the central cause of diabetes. The cellular response to stress (endoplasmic reticulum (ER), oxidative, inflammatory) is essential to sustain normal β cell function and survival. Pancreatic and duodenal homeobox 1 (PDX1), Activating transcription factor 4 (ATF4), and Activating transcription factor 5 (ATF5) are transcription factors implicated in β cell survival and susceptibility to stress. Our goal was to determine if a PDX1-ATF transcriptional complex or complexes regulate β cell survival in response to stress and to identify direct transcriptional targets. Methods Pdx1, Atf4 and Atf5 were silenced by viral delivery of gRNAs or shRNAs to Min6 insulinoma cells or primary murine islets. Gene expression was assessed by qPCR, RNAseq analysis, and Western blot analysis. Chromatin enrichment was measured in the Min6 β cell line and primary isolated mouse islets by ChIPseq and ChIP PCR. Immunoprecipitation was used to assess interactions among transcription factors in Min6 cells and isolated mouse islets. Activation of caspase 3 by immunoblotting or by irreversible binding to a fluorescent inhibitor was taken as an indication of commitment to an apoptotic fate. Results RNASeq identified a set of PDX1, ATF4 and ATF5 co-regulated genes enriched in stress and apoptosis functions. We further identified stress induced interactions among PDX1, ATF4, and ATF5. PDX1 chromatin occupancy peaks were identified over composite C/EBP-ATF (CARE) motifs of 26 genes; assessment of a subset of these genes revealed co-enrichment for ATF4 and ATF5. PDX1 occupancy over CARE motifs was conserved in the human orthologs of 9 of these genes. Of these, Glutamate Pyruvate Transaminase 2 (Gpt2), Cation transport regulator 1 (Chac1), and Solute Carrier Family 7 Member 1 (Slc7a1) induction by stress was conserved in human islets and abrogated by deficiency of Pdx1, Atf4, and Atf5 in Min6 cells. Deficiency of Gpt2 reduced β cell susceptibility to stress induced apoptosis in both Min6 cells and primary islets. Conclusions Our results identify a novel PDX1 stress inducible complex (es) that regulates expression of stress and apoptosis genes to govern β cell survival. PDX1 binds to composite CEBP/ATF (CARE) sites of stress and apoptosis genes. A novel stress inducible transcriptional complex involving PDX1, ATF4, and ATF5 is discovered. Novel stress induced targets of the complex involved in fate decisions are identified. Silencing of one of these targets, Gpt2, protects β cells from apoptosis due to stress.
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63
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Hacker B, Schultheiß C, Döring M, Kurzik-Dumke U. Molecular partners of hNOT/ALG3, the human counterpart of the Drosophila NOT and yeast ALG3 gene, suggest its involvement in distinct cellular processes relevant to congenital disorders of glycosylation, cancer, neurodegeneration and a variety of further pathologies. Hum Mol Genet 2018; 27:1858-1878. [DOI: 10.1093/hmg/ddy087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 03/06/2018] [Indexed: 01/04/2023] Open
Affiliation(s)
- Benedikt Hacker
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Christoph Schultheiß
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Michael Döring
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Ursula Kurzik-Dumke
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
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64
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Smith JA. Regulation of Cytokine Production by the Unfolded Protein Response; Implications for Infection and Autoimmunity. Front Immunol 2018; 9:422. [PMID: 29556237 PMCID: PMC5844972 DOI: 10.3389/fimmu.2018.00422] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/16/2018] [Indexed: 12/14/2022] Open
Abstract
Protein folding in the endoplasmic reticulum (ER) is an essential cell function. To safeguard this process in the face of environmental threats and internal stressors, cells mount an evolutionarily conserved response known as the unfolded protein response (UPR). Invading pathogens induce cellular stress that impacts protein folding, thus the UPR is well situated to sense danger and contribute to immune responses. Cytokines (inflammatory cytokines and interferons) critically mediate host defense against pathogens, but when aberrantly produced, may also drive pathologic inflammation. The UPR influences cytokine production on multiple levels, from stimulation of pattern recognition receptors, to modulation of inflammatory signaling pathways, and the regulation of cytokine transcription factors. This review will focus on the mechanisms underlying cytokine regulation by the UPR, and the repercussions of this relationship for infection and autoimmune/autoinflammatory diseases. Interrogation of viral and bacterial infections has revealed increasing numbers of examples where pathogens induce or modulate the UPR and implicated UPR-modulated cytokines in host response. The flip side of this coin, the UPR/ER stress responses have been increasingly recognized in a variety of autoimmune and inflammatory diseases. Examples include monogenic disorders of ER function, diseases linked to misfolding protein (HLA-B27 and spondyloarthritis), diseases directly implicating UPR and autophagy genes (inflammatory bowel disease), and autoimmune diseases targeting highly secretory cells (e.g., diabetes). Given the burgeoning interest in pharmacologically targeting the UPR, greater discernment is needed regarding how the UPR regulates cytokine production during specific infections and autoimmune processes, and the relative place of this interaction in pathogenesis.
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Affiliation(s)
- Judith A Smith
- Department of Pediatrics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States.,Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States
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65
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Oh-Hashi K, Soga A, Naruse Y, Takahashi K, Kiuchi K, Hirata Y. Elucidating post-translational regulation of mouse CREB3 in Neuro2a cells. Mol Cell Biochem 2018; 448:287-297. [PMID: 29455434 DOI: 10.1007/s11010-018-3333-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/09/2018] [Indexed: 12/30/2022]
Abstract
CREB3 is an ER membrane-bound transcription factor; however, post-translational regulation of CREB3, including expression, processing, and activation, is not fully characterized. We therefore constructed several types of mouse CREB3 expression genes and elucidated their expression in Neuro2a cells by treatment with stimuli and co-transfection with genes associated with ER-Golgi homeostasis, such as mutant Sar1 [H79G], GRP78, and KDEL receptor 1 (KDELR1). Interestingly, treatment of Neuro2a cells expressing Flag-tagged full-length CREB3 with monensin and nigericin induced the expression of the approximately 50 kDa N-terminal fragment; however, its cleavage was not parallel to the levels of GADD153 and LC3-II. Co-transfection of full-length CREB3 together with Sar1 [H79G], GRP78, or KDELR1 showed that only Sar1 [H79G] induced expression of the cleaved form, and KDELR1 dramatically decreased the expression of the full-length form. Accordingly, Sar1 [H79G]- and KDELR1-overexpression influenced GAL4-CREB3-dependent luciferase activities. To understand the activation of CREB3 under more pathophysiological conditions, we focused on the effect of metal ions on CREB3 cleavage in Neuro2a cells. Among the six metal ions we tested, only copper ion stabilized full-length CREB3 expression. Copper ion also increased its N-terminal form and GAL4-CREB3-dependent luciferase activity, which was accompanied by the increase in the ubiquitinated proteins in Neuro2a cells. Taken together, CREB3 expression is regulated by multiple ER-Golgi resident factors in a post-translational manner, but its processing is not directly associated with ER stress and autophagic dysfunction. This finding is especially true for the unique action of the copper ion on CREB3 stabilization and processing in parallel to aberration of ubiquitin-proteasome system, which might provide new insights into understanding the mechanisms of intractable disorders.
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Affiliation(s)
- Kentaro Oh-Hashi
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan. .,Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
| | - Ayano Soga
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Yoshihisa Naruse
- Department of Natural Science, Medical Education and Research Center, Meiji University of Integrative Medicine, Hiyoshi-cho, Nantan-shi, Kyoto, 629-0392, Japan
| | - Kanto Takahashi
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Kazutoshi Kiuchi
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.,Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Yoko Hirata
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.,Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
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66
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Rutkowski DT. Liver function and dysfunction - a unique window into the physiological reach of ER stress and the unfolded protein response. FEBS J 2018; 286:356-378. [PMID: 29360258 DOI: 10.1111/febs.14389] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/08/2018] [Accepted: 01/17/2018] [Indexed: 02/06/2023]
Abstract
The unfolded protein response (UPR) improves endoplasmic reticulum (ER) protein folding in order to alleviate stress. Yet it is becoming increasingly clear that the UPR regulates processes well beyond those directly involved in protein folding, in some cases by mechanisms that fall outside the realm of canonical UPR signaling. These pathways are highly specific from one cell type to another, implying that ER stress signaling affects each tissue in a unique way. Perhaps nowhere is this more evident than in the liver, which-beyond being a highly secretory tissue-is a key regulator of peripheral metabolism and a uniquely proliferative organ upon damage. The liver provides a powerful model system for exploring how and why the UPR extends its reach into physiological processes that occur outside the ER, and how ER stress contributes to the many systemic diseases that involve liver dysfunction. This review will highlight the ways in which the study of ER stress in the liver has expanded the view of the UPR to a response that is a key guardian of cellular homeostasis outside of just the narrow realm of ER protein folding.
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Affiliation(s)
- D Thomas Rutkowski
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, IA, USA.,Department of Internal Medicine, University of Iowa Carver College of Medicine, IA, USA
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67
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González-Quiroz M, Urra H, Limia CM, Hetz C. Homeostatic interplay between FoxO proteins and ER proteostasis in cancer and other diseases. Semin Cancer Biol 2018; 50:42-52. [PMID: 29369790 DOI: 10.1016/j.semcancer.2018.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 01/14/2018] [Accepted: 01/18/2018] [Indexed: 02/08/2023]
Abstract
Cancer cells are exposed to adverse conditions within the tumor microenvironment that challenge cells to adapt and survive. Several of these homeostatic perturbations insults alter the normal function of the endoplasmic reticulum (ER), resulting in the accumulation of misfolded proteins. ER stress triggers a conserved signaling pathway known as the unfolded protein response (UPR) to cope with the stress or trigger apoptosis of damaged cells. The UPR has been described as a major driver in the acquisition of malignant characteristics that ultimately lead to cancer progression. Although, several reports describe the relevance of the UPR in tumor growth, the possible crosstalk with other cancer-related pathways is starting to be elucidated. The Forkhead Box O (FoxO) subfamily of proteins has a major role in cancer progression, where chromosomal translocations and deregulated signaling lead to loss-of-function of FoxO proteins, contributing to tumor progression. Here we discuss the homeostatic connection between the UPR and FoxO proteins and its possible implications to tumor progression and the acquisition of several hallmarks of cancer. In addition, studies linking a crosstalk between the UPR and FoxO proteins in other diseases, including neurodegeneration and metabolic disorders is provided.
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Affiliation(s)
- Matías González-Quiroz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Hery Urra
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Celia María Limia
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile; The Buck Institute for Research in Aging, Novato CA 94945, USA; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston MA 02115, USA.
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68
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The Unfolded Protein Response in Chronic Obstructive Pulmonary Disease. Ann Am Thorac Soc 2018; 13 Suppl 2:S138-45. [PMID: 27115948 DOI: 10.1513/annalsats.201506-320kv] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Accumulation of nonfunctional and potentially cytotoxic, misfolded proteins in chronic obstructive pulmonary disease (COPD) is believed to contribute to lung cell apoptosis, inflammation, and autophagy. Because of its fundamental role as a quality control system in protein metabolism, the "unfolded protein response" (UPR) is of potential importance in the pathogenesis of COPD. The UPR comprises a series of transcriptional, translational, and post-translational processes that decrease protein synthesis while enhancing protein folding capacity and protein degradation. Several studies have suggested that the UPR contributes to lung cell apoptosis and lung inflammation in at least some subjects with human COPD. However, information on the prevalence of the UPR in subjects with COPD, the lung cells that manifest a UPR, and the role of the UPR in the pathogenesis of COPD is extremely limited and requires additional study.
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69
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Liu X, Wang J, Gao L, Jiao Y, Liu C. Maternal Protein Restriction Induces Alterations in Hepatic Unfolded Protein Response-Related Molecules in Adult Rat Offspring. Front Endocrinol (Lausanne) 2018; 9:676. [PMID: 30524373 PMCID: PMC6262354 DOI: 10.3389/fendo.2018.00676] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 10/29/2018] [Indexed: 12/13/2022] Open
Abstract
Intrauterine growth restriction (IUGR) leads to the development of metabolic syndrome in adulthood. To explore the potential mechanisms of metabolic imprinting, we investigated the effect of malnutrition in utero on hepatic unfolded protein response (UPR)-related genes in IUGR offspring. An IUGR rat model was developed by feeding a low-protein diet to pregnant rats. The expression levels and activity of hepatic UPR genes were analysed by quantitative PCR (qPCR) arrays and western blotting. The hepatic UPR molecules heat-shock 70-kDa protein 4l (Hspa4l), mitogen-activated protein kinase 10 (Mapk10), and endoplasmic reticulum to nucleus signalling 2 (Ern2) were markedly downregulated in IUGR foetuses, but the expression of Mapk10 and Ern2 returned to normal levels at 3 weeks postnatal. In contrast, cAMP responsive element binding protein 3-like 3 (Creb3l3) was upregulated in hepatic tissues at embryo 20(E20), then restored to normal in adulthood (12 weeks). The protein levels of activating transcription factor 2 (Atf2) and Atf6, two key factors of the UPR pathway, were upregulated in the livers of IUGR foetuses, and the latter remained upregulated until 12 weeks. Combined with our previous findings showing an increase in hepatic gluconeogenesis enzymes in IUGR offspring, we speculated that aberrant intrauterine milieu impaired UPR signalling in hepatic tissues; these alterations early in life might contribute to the predisposition of IUGR foetuses to adult metabolic disorders.
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Affiliation(s)
- Xiaomei Liu
- Key Laboratory of Maternal-fetal Medicine of Liaoning Province, Shengjing Hospital, China Medical University, Shenyang, China
- *Correspondence: Xiaomei Liu
| | - Jun Wang
- Key Laboratory of Maternal-fetal Medicine of Liaoning Province, Shengjing Hospital, China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Benxi Central Hospital of China Medical University, Benxi, China
| | - Linlin Gao
- Medical Research Center, Shengjing Hospital, China Medical University, Shenyang, China
| | - Yisheng Jiao
- Department of Obstetrics and Gynaecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Caixia Liu
- Department of Obstetrics and Gynaecology, Shengjing Hospital of China Medical University, Shenyang, China
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70
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Kim SY, Kyaw YY, Cheong J. Functional interaction of endoplasmic reticulum stress and hepatitis B virus in the pathogenesis of liver diseases. World J Gastroenterol 2017; 23:7657-7665. [PMID: 29209107 PMCID: PMC5703926 DOI: 10.3748/wjg.v23.i43.7657] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/01/2017] [Accepted: 11/01/2017] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) is a non-cytopathic virus that causes acute and chronic inflammatory liver diseases, often leading to the pathogenesis of hepatocellular carcinoma (HCC). Although many studies for the roles of HBV on pathogenesis of the liver diseases, such as non-alcoholic fatty liver disease (NAFLD), hepatic inflammation, cirrhosis, and HCC, have been reported, the mechanisms are not fully understood. Endoplasmic reticulum (ER) and mitochondria have the protective mechanisms to restore their damaged function by intrinsic or extrinsic stresses, but their chronic dysfunctions are associated with the pathogenesis of the various diseases. Furthermore, HBV can affect intra- or extracellular homeostasis through induction of ER and mitochondrial dysfunctions, leading to liver injury. Therefore, the mechanism by which HBV induces ER or mitochondrial stresses may be a therapeutic target for treatment of liver diseases.
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Affiliation(s)
- So Young Kim
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Yi Yi Kyaw
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
| | - Jaehun Cheong
- Department of Molecular Biology, Pusan National University, Busan 609-735, South Korea
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71
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Ma X, Dai Z, Sun K, Zhang Y, Chen J, Yang Y, Tso P, Wu G, Wu Z. Intestinal Epithelial Cell Endoplasmic Reticulum Stress and Inflammatory Bowel Disease Pathogenesis: An Update Review. Front Immunol 2017; 8:1271. [PMID: 29118753 PMCID: PMC5660968 DOI: 10.3389/fimmu.2017.01271] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 09/25/2017] [Indexed: 12/18/2022] Open
Abstract
The intestinal epithelial cells serve essential roles in maintaining intestinal homeostasis, which relies on appropriate endoplasmic reticulum (ER) function for proper protein folding, modification, and secretion. Exogenous or endogenous risk factors with an ability to disturb the ER function can impair the intestinal barrier function and activate inflammatory responses in the host. The last decade has witnessed considerable progress in the understanding of the functional role of ER stress and unfolded protein response (UPR) in the gut homeostasis and its significant contribution to the pathogenesis of inflammatory bowel disease (IBD). Herein, we review recent evidence supporting the viewpoint that deregulation of ER stress and UPR signaling in the intestinal epithelium, including the absorptive cells, Paneth cells, goblet cells, and enteroendocrine cells, mediates the action of genetic or environmental factors driving colitis in experimental animals and IBD patients. In addition, we highlight pharmacologic application of chaperones or small molecules that enhance protein folding and modification capacity or improve the function of the ER. These molecules represent potential therapeutic strategies in the prevention or treatment of IBD through restoring ER homeostasis in intestinal epithelial cells.
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Affiliation(s)
- Xiaoshi Ma
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Zhaolai Dai
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Kaiji Sun
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Yunchang Zhang
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Jingqing Chen
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Ying Yang
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH, United States
| | - Guoyao Wu
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China.,Department of Animal Science, Texas A&M University, College Station, TX, United States
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China.,Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China
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72
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Cnop M, Toivonen S, Igoillo-Esteve M, Salpea P. Endoplasmic reticulum stress and eIF2α phosphorylation: The Achilles heel of pancreatic β cells. Mol Metab 2017; 6:1024-1039. [PMID: 28951826 PMCID: PMC5605732 DOI: 10.1016/j.molmet.2017.06.001] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/19/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pancreatic β cell dysfunction and death are central in the pathogenesis of most if not all forms of diabetes. Understanding the molecular mechanisms underlying β cell failure is important to develop β cell protective approaches. SCOPE OF REVIEW Here we review the role of endoplasmic reticulum stress and dysregulated endoplasmic reticulum stress signaling in β cell failure in monogenic and polygenic forms of diabetes. There is substantial evidence for the presence of endoplasmic reticulum stress in β cells in type 1 and type 2 diabetes. Direct evidence for the importance of this stress response is provided by an increasing number of monogenic forms of diabetes. In particular, mutations in the PERK branch of the unfolded protein response provide insight into its importance for human β cell function and survival. The knowledge gained from different rodent models is reviewed. More disease- and patient-relevant models, using human induced pluripotent stem cells differentiated into β cells, will further advance our understanding of pathogenic mechanisms. Finally, we review the therapeutic modulation of endoplasmic reticulum stress and signaling in β cells. MAJOR CONCLUSIONS Pancreatic β cells are sensitive to excessive endoplasmic reticulum stress and dysregulated eIF2α phosphorylation, as indicated by transcriptome data, monogenic forms of diabetes and pharmacological studies. This should be taken into consideration when devising new therapeutic approaches for diabetes.
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Key Words
- ATF, activating transcription factor
- CHOP, C/EBP homologous protein
- CRISPR, clustered regularly interspaced short palindromic repeats
- CReP, constitutive repressor of eIF2α phosphorylation
- Diabetes
- ER, endoplasmic reticulum
- ERAD, ER-associated degradation
- Endoplasmic reticulum stress
- GCN2, general control non-derepressible-2
- GIP, glucose-dependent insulinotropic polypeptide
- GLP-1, glucagon-like peptide 1
- GWAS, genome-wide association study
- HNF1A, hepatocyte nuclear factor 1-α
- HRI, heme-regulated inhibitor kinase
- IAPP, islet amyloid polypeptide
- IER3IP1, immediate early response-3 interacting protein-1
- IRE1, inositol-requiring protein-1
- ISR, integrated stress response
- Insulin
- Islet
- MEHMO, mental retardation, epilepsy, hypogonadism and -genitalism, microcephaly and obesity
- MODY, maturity-onset diabetes of the young
- NRF2, nuclear factor, erythroid 2 like 2
- PBA, 4-phenyl butyric acid
- PERK, PKR-like ER kinase
- PKR, protein kinase RNA
- PP1, protein phosphatase 1
- PPA, phenylpropenoic acid glucoside
- Pancreatic β cell
- Pdx1, pancreatic duodenal homeobox 1
- RIDD, regulated IRE1-dependent decay
- RyR2, type 2 ryanodine receptor/Ca2+ release channel
- SERCA, sarcoendoplasmic reticulum Ca2+ ATPase
- TUDCA, taurine-conjugated ursodeoxycholic acid derivative
- UPR, unfolded protein response
- WFS, Wolfram syndrome
- XBP1, X-box binding protein 1
- eIF2, eukaryotic translation initiation factor 2
- eIF2α
- hESC, human embryonic stem cell
- hPSC, human pluripotent stem cell
- hiPSC, human induced pluripotent stem cell
- uORF, upstream open reading frame
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Affiliation(s)
- Miriam Cnop
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Sanna Toivonen
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Paraskevi Salpea
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
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73
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Mügge FLB, Silva AM. Aspirin metabolite sodium salicylate selectively inhibits transcriptional activity of ATF6α and downstream target genes. Sci Rep 2017; 7:9190. [PMID: 28835710 PMCID: PMC5569067 DOI: 10.1038/s41598-017-09500-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/26/2017] [Indexed: 12/27/2022] Open
Abstract
In response to ER stress, activating transcription factor 6 (ATF6) traffics from ER to Golgi apparatus where it is activated by cleavage before being translocated as transcription factor to the cell nucleus. In this work we describe ATF6α as a newly target of the aspirin metabolite sodium salicylate (NaSal). NaSal treatment of cells induces increases in ATF6α mRNA and protein levels, but these events are not accompanied by ATF6 activation. Conversely, NaSal inhibited ATF6 transactivating activity elicited by various ER stress-inducing stimuli in different cell types. This resulted in reduced expression of a subset of ATF6α target genes. Mechanistically, exposure of cells to NaSal results in ATF6α trapping at the Golgi apparatus, thus preventing nuclear translocation. This study provides evidence that NaSal compound restrains the activity of ATF6α, thereby preventing activation of a specific subset of ER-stress responsive genes implicated in different cellular responses.
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Affiliation(s)
- Fernanda L B Mügge
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Aristóbolo M Silva
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
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74
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Keller RB, Tran TT, Pyott SM, Pepin MG, Savarirayan R, McGillivray G, Nickerson DA, Bamshad MJ, Byers PH. Monoallelic and biallelic CREB3L1 variant causes mild and severe osteogenesis imperfecta, respectively. Genet Med 2017; 20:411-419. [PMID: 28817112 PMCID: PMC5816725 DOI: 10.1038/gim.2017.115] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/05/2017] [Indexed: 12/11/2022] Open
Abstract
Purpose Osteogenesis imperfecta (OI) is a heritable skeletal dysplasia. Dominant pathogenic variants in COL1A1 and COL1A2 explain the majority of OI cases. At least fifteen additional genes have been identified, but still do not account for all OI phenotypes that present. We sought the genetic cause of mild and lethal OI phenotypes in an unsolved family. Methods We performed exome sequencing on seven members of the family, both affected and unaffected. Results We identified a variant in Cyclic AMP Responsive Element Binding Protein 3-Like 1 (CREB3L1) in a consanguineous family. The variant caused a prenatal/perinatal lethal OI in homozygotes, similar to that seen in OI type II as a result of mutations in type I collagen genes, and a mild phenotype (fractures, blue sclerae) in multiple heterozygous family members. CREB3L1 encodes Old Astrocyte Specifically-Induced Substance (OASIS), an ER stress transducer. The variant disrupts a DNA-binding site and prevents OASIS from acting on its transcriptional targets including SEC24D, which encodes a component of the coat protein II (COPII) complex. Conclusion This report confirms that CREB3L1 is an OI-related gene and suggests the pathogenic mechanism of CREB3L1-associated OI involves the altered regulation of proteins involved in cellular secretion.
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Affiliation(s)
- Rachel B Keller
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Thao T Tran
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Shawna M Pyott
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Melanie G Pepin
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Ravi Savarirayan
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - George McGillivray
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Deborah A Nickerson
- Center for Mendelian Genomics, University of Washington, Seattle, Washington, USA
| | - Michael J Bamshad
- Center for Mendelian Genomics, University of Washington, Seattle, Washington, USA
| | - Peter H Byers
- Department of Pathology, University of Washington, Seattle, Washington, USA.,Department of Medicine (Medical Genetics), University of Washington, Seattle, Washington, USA
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75
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Ishikawa T, Toyama T, Nakamura Y, Tamada K, Shimizu H, Ninagawa S, Okada T, Kamei Y, Ishikawa-Fujiwara T, Todo T, Aoyama E, Takigawa M, Harada A, Mori K. UPR transducer BBF2H7 allows export of type II collagen in a cargo- and developmental stage-specific manner. J Cell Biol 2017; 216:1761-1774. [PMID: 28500182 PMCID: PMC5461018 DOI: 10.1083/jcb.201609100] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 03/05/2017] [Accepted: 04/12/2017] [Indexed: 12/22/2022] Open
Abstract
The unfolded protein response (UPR) handles unfolded/misfolded proteins accumulated in the endoplasmic reticulum (ER). However, it is unclear how vertebrates correctly use the total of ten UPR transducers. We have found that ER stress occurs physiologically during early embryonic development in medaka fish and that the smooth alignment of notochord cells requires ATF6 as a UPR transducer, which induces ER chaperones for folding of type VIII (short-chain) collagen. After secretion of hedgehog for tissue patterning, notochord cells differentiate into sheath cells, which synthesize type II collagen. In this study, we show that this vacuolization step requires both ATF6 and BBF2H7 as UPR transducers and that BBF2H7 regulates a complete set of genes (Sec23/24/13/31, Tango1, Sedlin, and KLHL12) essential for the enlargement of COPII vesicles to accommodate long-chain collagen for export, leading to the formation of the perinotochordal basement membrane. Thus, the most appropriate UPR transducer is activated to cope with the differing physiological ER stresses of different content types depending on developmental stage.
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Affiliation(s)
- Tokiro Ishikawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Takuya Toyama
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yuki Nakamura
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kentaro Tamada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hitomi Shimizu
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Tetsuya Okada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yasuhiro Kamei
- Spectrography and Bioimaging Facility, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Tomoko Ishikawa-Fujiwara
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Takeshi Todo
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Eriko Aoyama
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8525, Japan
| | - Masaharu Takigawa
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8525, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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76
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Bose S, Cho J. Targeting chaperones, heat shock factor-1, and unfolded protein response: Promising therapeutic approaches for neurodegenerative disorders. Ageing Res Rev 2017; 35:155-175. [PMID: 27702699 DOI: 10.1016/j.arr.2016.09.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/02/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022]
Abstract
Protein misfolding, which is known to cause several serious diseases, is an emerging field that addresses multiple therapeutic areas. Misfolding of a disease-specific protein in the central nervous system ultimately results in the formation of toxic aggregates that may accumulate in the brain, leading to neuronal cell death and dysfunction, and associated clinical manifestations. A large number of neurodegenerative diseases in humans, including Alzheimer's, Parkinson's, Huntington's, and prion diseases, are primarily caused by protein misfolding and aggregation. Notably, the cellular system is equipped with a protein quality control system encompassing chaperones, ubiquitin proteasome system, and autophagy, as a defense mechanism that monitors protein folding and eliminates inappropriately folded proteins. As the intrinsic molecular mechanisms of protein misfolding become more clearly understood, the novel therapeutic approaches in this arena are gaining considerable interest. The present review will describe the chaperones network and different approaches as the therapeutic targets for neurodegenerative diseases. Current and emerging therapeutic approaches to combat neurodegenerative diseases, addressing the roles of molecular, chemical, and pharmacological chaperones, as well as heat shock factor-1 and the unfolded protein response, are also discussed in detail.
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Affiliation(s)
- Shambhunath Bose
- College of Pharmacy, Dongguk University-Seoul, Goyang, Gyeonggi-do 10326, Republic of Korea
| | - Jungsook Cho
- College of Pharmacy, Dongguk University-Seoul, Goyang, Gyeonggi-do 10326, Republic of Korea.
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77
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Doultsinos D, Avril T, Lhomond S, Dejeans N, Guédat P, Chevet E. Control of the Unfolded Protein Response in Health and Disease. SLAS DISCOVERY 2017; 22:787-800. [PMID: 28453376 DOI: 10.1177/2472555217701685] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The unfolded protein response (UPR) is an integrated, adaptive biochemical process that is inextricably linked with cell homeostasis and paramount to maintenance of normal physiological function. Prolonged accumulation of improperly folded proteins in the endoplasmic reticulum (ER) leads to stress. This is the driving stimulus behind the UPR. As such, prolonged ER stress can push the UPR past beneficial functions such as reduced protein production and increased folding and clearance to apoptotic signaling. The UPR is thus contributory to the commencement, maintenance, and exacerbation of a multitude of disease states, making it an attractive global target to tackle conditions sorely in need of novel therapeutic intervention. The accumulation of information of screening tools, readily available therapies, and potential pathways to drug development is the cornerstone of informed clinical research and clinical trial design. Here, we review the UPR's involvement in health and disease and, beyond providing an in-depth description of the molecules found to target the three UPR arms, we compile all the tools available to screen for and develop novel therapeutic agents that modulate the UPR with the scope of future disease intervention.
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Affiliation(s)
- Dimitrios Doultsinos
- 1 Inserm U1242, Chemistry, Oncogenesis, Stress & Signaling, University of Rennes 1, Rennes, France.,2 Centre de Lutte contre le Cancer Eugène Marquis, Rennes, France
| | - Tony Avril
- 1 Inserm U1242, Chemistry, Oncogenesis, Stress & Signaling, University of Rennes 1, Rennes, France.,2 Centre de Lutte contre le Cancer Eugène Marquis, Rennes, France
| | | | | | | | - Eric Chevet
- 1 Inserm U1242, Chemistry, Oncogenesis, Stress & Signaling, University of Rennes 1, Rennes, France.,2 Centre de Lutte contre le Cancer Eugène Marquis, Rennes, France.,3 BMYscreen, Bergonié Cancer Institute, Bordeaux, France
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78
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Kim TH, Park JM, Kim MY, Ahn YH. The role of CREB3L4 in the proliferation of prostate cancer cells. Sci Rep 2017; 7:45300. [PMID: 28338058 PMCID: PMC5364418 DOI: 10.1038/srep45300] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/23/2017] [Indexed: 12/19/2022] Open
Abstract
The incidence of prostate cancer (PC) is growing rapidly throughout the world, in probable association with the adoption of western style diets. Thus, understanding the molecular pathways triggering the development of PC is crucial for both its prevention and treatment. Here, we investigated the role of the metabolism-associated protein, CREB3L4, in the proliferation of PC cells. CREB3L4 was upregulated by the synthetic androgen, R1881, in LNCaP PC cells (an androgen-dependent cell line). Knockdown of CREB3L4 resulted in decreased androgen-dependent PC cell growth. LNCaP cells transfected with siCREB3L4 underwent G2/M arrest, with upregulation of the proteins cyclin B1, phospho-CDK1, p21Waf1/Cip1, and INCA1, and downregulation of cyclin D1. Moreover, depletion of CREB3L4 resulted in significantly decreased expression of a subset of androgen-receptor (AR) target genes, including PSA, FKBP5, HPGD, KLK2, and KLK4. We also demonstrated that CREB3L4 directly interacts with the AR, and increases the binding of AR to androgen response elements (AREs). We also identified a role for the unfolded protein response (and its surrogate, IRE1α), in activating CREB3L4. Cumulatively, we postulate that CREB3L4 expression is mediated by an AR-IRE1α axis, but is also directly regulated by AR-to-ARE binding. Thus, our study demonstrates that CREB3L4 plays a key role in PC cell proliferation, which is promoted by both AR and IRE1α.
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Affiliation(s)
- Tae-Hyun Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Joo-Man Park
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Mi-Young Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Yong-Ho Ahn
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.,Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
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79
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Kang M, Kim J, An HT, Ko J. Human leucine zipper protein promotes hepatic steatosis via induction of apolipoprotein A-IV. FASEB J 2017; 31:2548-2561. [PMID: 28246167 DOI: 10.1096/fj.201601227r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/07/2017] [Indexed: 12/13/2022]
Abstract
The molecular mechanism of stress-induced hepatic steatosis is not well known. Human leucine zipper protein (LZIP) regulates the expression of genes involved in inflammation, cell migration, and stress response. The aim of this study was to determine the regulatory role of LZIP in stress-induced hepatic steatosis. We used a microarray analysis to identify LZIP-induced genes involved in hepatic lipid metabolism. LZIP increased the expression of apolipoprotein A-IV (APOA4) mRNA. In the presence of stress inducer, APOA4 promoter analysis was performed, and LZIP-induced lipid accumulation was monitored in mouse primary cells and human tissues. Under Golgi stress conditions, LZIP underwent proteolytic cleavage and was phosphorylated by AKT to protect against proteasome degradation. The stabilized N-terminal LZIP was translocated to the nucleus, where it directly bound to the APOA4 promoter, leading to APOA4 induction. LZIP-induced APOA4 expression resulted in increased absorption of surrounding free fatty acids. LZIP also promoted hepatic steatosis in mouse liver. Both LZIP and APOA4 were highly expressed in human steatosis samples. Our findings indicate that LZIP is a novel modulator of APOA4 expression and hepatic lipid metabolism. LZIP might be a therapeutic target for developing treatment strategies for hepatic steatosis and related metabolic diseases.-Kang, M., Kim, J., An, H.-T., Ko, J. Human leucine zipper protein promotes hepatic steatosis via induction of apolipoprotein A-IV.
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Affiliation(s)
| | | | | | - Jesang Ko
- Division of Life Sciences, Korea University, Seoul, South Korea
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80
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Luman contributes to brefeldin A-induced prion protein gene expression by interacting with the ERSE26 element. Sci Rep 2017; 7:42285. [PMID: 28205568 PMCID: PMC5304227 DOI: 10.1038/srep42285] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 01/06/2017] [Indexed: 01/17/2023] Open
Abstract
The cellular prion protein (PrP) is essential for transmissible prion diseases, but its exact physiological function remains unclear. Better understanding the regulation of the human prion protein gene (PRNP) expression can provide insight into this elusive function. Spliced XBP1 (sXBP1) was recently shown to mediate endoplasmic reticulum (ER) stress-induced PRNP expression. In this manuscript, we identify Luman, a ubiquitous, non-canonical unfolded protein response (UPR), as a novel regulator of ER stress-induced PRNP expression. Luman activity was transcriptionally and proteolytically activated by the ER stressing drug brefeldin A (BFA) in human neurons, astrocytes, and breast cancer MCF-7 cells. Over-expression of active cleaved Luman (ΔLuman) increased PrP levels, while siRNA-mediated Luman silencing decreased BFA-induced PRNP expression. Site-directed mutagenesis and chromatin immunoprecipitation demonstrated that ΔLuman regulates PRNP expression by interacting with the ER stress response element 26 (ERSE26). Co-over-expression and siRNA-mediated silencing experiments showed that sXBP1 and ΔLuman both up-regulate ER stress-induced PRNP expression. Attempts to understand the function of PRNP up-regulation by Luman excluded a role in atorvastatin-induced neuritogenesis, ER-associated degradation, or proteasomal inhibition-induced cell death. Overall, these results refine our understanding of ER stress-induced PRNP expression and function.
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81
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Ariyasu D, Yoshida H, Hasegawa Y. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders. Int J Mol Sci 2017; 18:ijms18020382. [PMID: 28208663 PMCID: PMC5343917 DOI: 10.3390/ijms18020382] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/24/2017] [Accepted: 02/03/2017] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum (ER) is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR), which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI), Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2) are discussed in this article.
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Affiliation(s)
- Daisuke Ariyasu
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan.
| | - Hiderou Yoshida
- Department of Biochemistry and Molecular Biology, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan.
| | - Yukihiro Hasegawa
- Division of Endocrinology and Metabolism, Tokyo Metropolitan Children's Medical Center, Tokyo 183-8561, Japan.
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82
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Ahn JI, Yoo JY, Kim TH, Kim YI, Ferguson SD, Fazleabas AT, Young SL, Lessey BA, Ahn JY, Lim JM, Jeong JW. cAMP-Response Element-Binding 3-Like Protein 1 (CREB3L1) is Required for Decidualization and its Expression is Decreased in Women with Endometriosis. Curr Mol Med 2016; 16:276-87. [PMID: 26917262 DOI: 10.2174/1566524016666160225153659] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 02/10/2016] [Accepted: 02/19/2016] [Indexed: 11/22/2022]
Abstract
Endometriosis is a major cause of infertility and pelvic pain, affecting more than 10% of reproductive-aged women. Progesterone resistance has been observed in the endometrium of women with this disease, as evidenced by alterations in progesterone-responsive gene and protein expression. cAMPResponse Element-Binding 3-like protein 1 (Creb3l1) has previously been identified as a progesterone receptor (PR) target gene in mouse uterus via high density DNA microarray analysis. However, CREB3L1 function has not been studied in the context of endometriosis and uterine biology. In this study, we validated progesterone (P4) regulation of Creb3l1 in the uteri of wild-type and progesterone receptor knockout (PRKO) mice. Furthermore, we observed that CREB3L1 expression was significantly higher in secretory phase human endometrium compared to proliferative phase and that CREB3L1 expression was significantly decreased in the endometrium of women with endometriosis. Lastly, by transfecting CREB3L1 siRNA into cultured human endometrial stromal cells (hESCs) prior to hormonal induction of in vitro decidualization, we showed that CREB3L1 is required for the decidualization process. Interestingly, phosphorylation of ERK1/2, critical factor for decidualization, was also significantly reduced in CREB3L1-silenced hESCs. It is known that hESCs from patients with endometriosis show impaired decidualization and that dysregulation of the P4-PR signaling axis is linked to a variety of endometrial diseases including infertility and endometriosis. Therefore, these results suggest that CREB3L1 is required for decidualization in mice and humans and may be linked to the pathogenesis of endometriosis in a P4-dependent manner.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - J M Lim
- Laboratory of Stem Cell and Bioevaluation, Major in Biomodulation, Seoul National University, Seoul 151-921, Republic of Korea.
| | - J-W Jeong
- Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, College of Human Medicine, 333 Bostwick Avenue NE, Suite 4024, Grand Rapids, MI 49503, USA.
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83
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The androgen-induced protein AIbZIP facilitates proliferation of prostate cancer cells through downregulation of p21 expression. Sci Rep 2016; 6:37310. [PMID: 27853318 PMCID: PMC5112536 DOI: 10.1038/srep37310] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/19/2016] [Indexed: 01/01/2023] Open
Abstract
Androgen-Induced bZIP (AIbZIP) is structurally a bZIP transmembrane transcription factor belonging to the CREB/ATF family. This molecule is highly expressed in androgen-sensitive prostate cancer cells and is transcriptionally upregulated by androgen treatment. Here, we investigated molecular mechanism of androgen-dependent expression of AIbZIP and its physiological function in prostate cancer cells. Our data showed that SAM pointed domain-containing ETS transcription factor (SPDEF), which is upregulated by androgen treatment, directly activates transcription of AIbZIP. Knockdown of AIbZIP caused a significant reduction in the proliferation of androgen-sensitive prostate cancer cells with robust expression of p21. Mechanistically, we demonstrated that AIbZIP interacts with old astrocyte specifically induced substance (OASIS), which is a CREB/ATF family transcription factor, and prevents OASIS from promoting transcription of its target gene p21. These findings showed that AIbZIP induced by the androgen receptor (AR) axis plays a crucial role in the proliferation of androgen-sensitive prostate cancer cells, and could be a novel target of therapy for prostate cancer.
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84
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Li YH, Tardif G, Hum D, Kapoor M, Fahmi H, Pelletier JP, Martel-Pelletier J. The unfolded protein response genes in human osteoarthritic chondrocytes: PERK emerges as a potential therapeutic target. Arthritis Res Ther 2016; 18:172. [PMID: 27435272 PMCID: PMC4952234 DOI: 10.1186/s13075-016-1070-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/30/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The unfolded protein response (UPR) is activated following an endoplasmic reticulum (ER) stress. The aim of this study was to investigate the global expression of UPR genes in human OA chondrocytes in induced (I)-UPR conditions, and to explore the regulation and role of the UPR genes in homeostatic (H)-UPR conditions in human normal and OA chondrocytes. METHODS Gene expression was determined by PCR array and qPCR. Protein production in cartilage was determined by immunohistochemistry, gene silencing by specific siRNAs, and gene regulation by treating chondrocytes with cytokines and growth factors associated with cartilage pathobiology. RESULTS Several UPR genes, among them ERN1, PERK, and CREB3L2 were downregulated in OA compared to normal chondrocytes at both the mRNA and protein levels, but the ER stress response triggered by thapsigargin or tunicamycin treatment was similar in normal and OA chondrocytes. The activation of ER stress sensors (phosphorylated PERK, cleavage of ATF6B, and the spliced mRNA forms of XBP1) was not significantly increased in OA chondrocytes/cartilage. PDGF-BB and IL-6 significantly downregulated the expression of ERN1, PERK, and CREB3L2, but not that of ATF6B. Silencing experiments done under conditions of no ER stress (physiological conditions) revealed that decreasing ERN1 expression led to decreased COL2a1, MMP-13, ADAMTS4 and ADAMTS5 expression, while decreasing CREB3L2 and ATF6B led to decreased ADAMTS5 and ADAMTS4 expression, respectively. Importantly, the downregulation of PERK expression increased COL1a1 and suppressed COL2a1 expression. CONCLUSIONS Although the level of ER stress is not significantly increased in OA chondrocytes, these cells respond strongly to an acute ER stress despite the decreased expression of ERN1, PERK, and CREB3L2. Emerging findings revealed for the first time that these genes play a role in cartilage biology in conditions where an acute ER stress response is not triggered and OA is not characterized by an overall basal activation of the ER stress response. Importantly, these findings identify PERK as a potential target for new OA treatment avenues.
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Affiliation(s)
- Ying-Hua Li
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada
| | - Ginette Tardif
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada
| | - David Hum
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada
| | - Mohit Kapoor
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada.,Division of Genetics and Development, Toronto Western Research Institute, University Health Network (UHN), Toronto, ON, Canada.,Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Hassan Fahmi
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada
| | - Jean-Pierre Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada
| | - Johanne Martel-Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), 900 Saint-Denis, R11.412B, Montreal, QC, H2X 0A9, Canada.
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85
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Mirabelli C, Pelletier I, Téoulé F, Vidalain PO, Brisac C, Tangy F, Delpeyroux F, Blondel B. The CREB3-Herp signalling module limits the cytosolic calcium concentration increase and apoptosis induced by poliovirus. J Gen Virol 2016; 97:2194-2200. [PMID: 27405867 DOI: 10.1099/jgv.0.000544] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Poliovirus (PV)-induced apoptosis seems to play a major role in central nervous system (CNS) tissue injury, a crucial feature of the pathogenesis of poliomyelitis. We have previously shown that calcium (Ca2+) flux from the endoplasmic reticulum (ER) to the cytosol during PV infection is involved in apoptosis induction in human neuroblastoma cells. We show here that PV infection is associated with a transient upregulation of Herp (homocysteine-induced ER protein), a protein known to promote the degradation of ER-resident Ca2+ channels. Herp gene transcription is controlled by the transcription factor CREB3 (cAMP response element-binding protein 3). We found that the CREB3/Herp pathway limited the increase in cytosolic Ca2+ concentration and apoptosis early in PV infection. This may reduce the extent of PV-induced damage to the CNS during poliomyelitis.
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Affiliation(s)
- Carmen Mirabelli
- Institut Pasteur, Unité de Biologie des virus entériques, 25 rue du Dr Roux, 75015 Paris, France.,INSERM U994, Paris, France
| | - Isabelle Pelletier
- Institut Pasteur, Unité de Biologie des virus entériques, 25 rue du Dr Roux, 75015 Paris, France.,INSERM U994, Paris, France
| | - François Téoulé
- Institut Pasteur, Unité de Biologie des virus entériques, 25 rue du Dr Roux, 75015 Paris, France.,INSERM U994, Paris, France.,Université Versailles Saint-Quentin, Versailles, France
| | - Pierre-Olivier Vidalain
- Institut Pasteur, Unité de Génomique virale et vaccination, 25 rue du Dr Roux, 75015 Paris, France.,CNRS UMR 3569, Paris, France
| | - Cynthia Brisac
- Institut Pasteur, Unité de Biologie des virus entériques, 25 rue du Dr Roux, 75015 Paris, France.,Université Versailles Saint-Quentin, Versailles, France.,INSERM U994, Paris, France
| | - Frédéric Tangy
- Institut Pasteur, Unité de Génomique virale et vaccination, 25 rue du Dr Roux, 75015 Paris, France.,CNRS UMR 3569, Paris, France
| | - Francis Delpeyroux
- Institut Pasteur, Unité de Biologie des virus entériques, 25 rue du Dr Roux, 75015 Paris, France.,INSERM U994, Paris, France
| | - Bruno Blondel
- Institut Pasteur, Unité de Biologie des virus entériques, 25 rue du Dr Roux, 75015 Paris, France.,INSERM U994, Paris, France
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86
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Cheng Y, Gao WW, Tang HMV, Deng JJ, Wong CM, Chan CP, Jin DY. β-TrCP-mediated ubiquitination and degradation of liver-enriched transcription factor CREB-H. Sci Rep 2016; 6:23938. [PMID: 27029215 PMCID: PMC4814919 DOI: 10.1038/srep23938] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 03/16/2016] [Indexed: 12/13/2022] Open
Abstract
CREB-H is an endoplasmic reticulum-resident bZIP transcription factor which critically regulates lipid homeostasis and gluconeogenesis in the liver. CREB-H is proteolytically activated by regulated intramembrane proteolysis to generate a C-terminally truncated form known as CREB-H-ΔTC, which translocates to the nucleus to activate target gene expression. CREB-H-ΔTC is a fast turnover protein but the mechanism governing its destruction was not well understood. In this study, we report on β-TrCP-dependent ubiquitination and proteasomal degradation of CREB-H-ΔTC. The degradation of CREB-H-ΔTC was mediated by lysine 48-linked polyubiquitination and could be inhibited by proteasome inhibitor. CREB-H-ΔTC physically interacted with β-TrCP, a substrate recognition subunit of the SCFβ-TrCP E3 ubiquitin ligase. Forced expression of β-TrCP increased the polyubiquitination and decreased the stability of CREB-H-ΔTC, whereas knockdown of β-TrCP had the opposite effect. An evolutionarily conserved sequence, SDSGIS, was identified in CREB-H-ΔTC, which functioned as the β-TrCP-binding motif. CREB-H-ΔTC lacking this motif was stabilized and resistant to β-TrCP-induced polyubiquitination. This motif was a phosphodegron and its phosphorylation was required for β-TrCP recognition. Furthermore, two inhibitory phosphorylation sites close to the phosphodegron were identified. Taken together, our work revealed a new intracellular signaling pathway that controls ubiquitination and degradation of the active form of CREB-H transcription factor.
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Affiliation(s)
- Yun Cheng
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,State Key Laboratory for Liver Research, The University of Hong Kong, Pokfulam, Hong Kong
| | - Wei-Wei Gao
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,State Key Laboratory for Liver Research, The University of Hong Kong, Pokfulam, Hong Kong
| | - Hei-Man Vincent Tang
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,State Key Laboratory for Liver Research, The University of Hong Kong, Pokfulam, Hong Kong.,Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China
| | - Jian-Jun Deng
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,State Key Laboratory for Liver Research, The University of Hong Kong, Pokfulam, Hong Kong.,Department of Food Science and Engineering, College of Chemical Engineering, Northwestern University, Xi'an 710069, China
| | - Chi-Ming Wong
- Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China.,Department of Medicine and State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Pokfulam, Hong Kong
| | - Chi-Ping Chan
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,State Key Laboratory for Liver Research, The University of Hong Kong, Pokfulam, Hong Kong.,Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China
| | - Dong-Yan Jin
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.,State Key Laboratory for Liver Research, The University of Hong Kong, Pokfulam, Hong Kong.,Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China
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87
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Corcoran LM, Tarlinton DM. Regulation of germinal center responses, memory B cells and plasma cell formation-an update. Curr Opin Immunol 2016; 39:59-67. [PMID: 26799208 DOI: 10.1016/j.coi.2015.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/21/2015] [Accepted: 12/31/2015] [Indexed: 12/31/2022]
Abstract
Progress in understanding humoral immunity has been accelerated by the powerful experimental approaches of genetics, genomics and imaging. Excellent reviews of these advances appeared in 2015 in celebration of the 50th anniversary of the discovery of B cell and T cell lineages in the chicken. Here we provide a contemporary model of B cell differentiation, highlighting recent publications illuminating germinal center (GC), memory B cell and antibody-secreting plasma cell biology. The important contributions of CD4T cells to antibody responses have been thoroughly reviewed elsewhere.
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Affiliation(s)
- Lynn M Corcoran
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia.
| | - David M Tarlinton
- Immunology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia
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88
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WANG MIN, ZHAO SHUIPING, TAN MINGYUE. bZIP transmembrane transcription factor CREBH: Potential role in non-alcoholic fatty liver disease (Review). Mol Med Rep 2015; 13:1455-62. [DOI: 10.3892/mmr.2015.4749] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 12/02/2015] [Indexed: 11/06/2022] Open
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89
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Cui M, Kanemoto S, Cui X, Kaneko M, Asada R, Matsuhisa K, Tanimoto K, Yoshimoto Y, Shukunami C, Imaizumi K. OASIS modulates hypoxia pathway activity to regulate bone angiogenesis. Sci Rep 2015; 5:16455. [PMID: 26558437 PMCID: PMC4642342 DOI: 10.1038/srep16455] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/14/2015] [Indexed: 12/31/2022] Open
Abstract
OASIS/CREB3L1, an endoplasmic reticulum (ER)-resident transcription factor, plays important roles in osteoblast differentiation. In this study, we identified new crosstalk between OASIS and the hypoxia signaling pathway, which regulates vascularization during bone development. RT-PCR and real-time PCR analyses revealed significant decreases in the expression levels of hypoxia-inducible factor-1α (HIF-1α) target genes such as vascular endothelial growth factor A (VEGFA) in OASIS-deficient (Oasis−/−) mouse embryonic fibroblasts. In coimmunoprecipitation experiments, the N-terminal fragment of OASIS (OASIS-N; activated form of OASIS) bound to HIF-1α through the bZIP domain. Luciferase assays showed that OASIS-N promoted the transcription activities of a reporter gene via a hypoxia-response element (HRE). Furthermore, the expression levels of an angiogenic factor Vegfa was decreased in Oasis−/− osteoblasts. Immunostaining and metatarsal angiogenesis assay showed retarded vascularization in bone tissue of Oasis−/− mice. These results suggest that OASIS affects the expression of HIF-1α target genes through the protein interaction with HIF-1α, and that OASIS-HIF-1α complexes may play essential roles in angiogenesis during bone development.
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Affiliation(s)
- Min Cui
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Soshi Kanemoto
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Xiang Cui
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Masayuki Kaneko
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Rie Asada
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Koji Matsuhisa
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Keiji Tanimoto
- Department of Radiation Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan
| | - Yuki Yoshimoto
- Department of Molecular Biology and Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Chisa Shukunami
- Department of Molecular Biology and Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
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90
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Kanemoto S, Kobayashi Y, Yamashita T, Miyamoto T, Cui M, Asada R, Cui X, Hino K, Kaneko M, Takai T, Matsuhisa K, Takahashi N, Imaizumi K. Luman is involved in osteoclastogenesis through the regulation of DC-STAMP expression, stability and localization. J Cell Sci 2015; 128:4353-65. [PMID: 26503158 PMCID: PMC4712816 DOI: 10.1242/jcs.176057] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/19/2015] [Indexed: 01/12/2023] Open
Abstract
Luman (also known as CREB3) is a type-II transmembrane transcription factor belonging to the OASIS family that localizes to the endoplasmic reticulum (ER) membrane under normal conditions. In response to ER stress, OASIS-family members are subjected to regulated intramembrane proteolysis (RIP), following which the cleaved N-terminal fragments translocate to the nucleus. In this study, we show that treatment of bone marrow macrophages (BMMs) with cytokines – macrophage colony-stimulating factor (M-CSF) and RANKL (also known as TNFSF11) – causes a time-dependent increase in Luman expression, and that Luman undergoes RIP and becomes activated during osteoclast differentiation. Small hairpin (sh)RNA-mediated knockdown of Luman in BMMs prevented the formation of multinucleated osteoclasts, concomitant with the suppression of DC-STAMP, a protein that is essential for cell–cell fusion in osteoclastogenesis. The N-terminus of Luman facilitates promoter activity of DC-STAMP, resulting in upregulation of DC-STAMP expression. Furthermore, Luman interacts with DC-STAMP, and controls its stability and localization. These results suggest that Luman regulates the multinucleation of osteoclasts by promoting cell fusion of mononuclear osteoclasts through DC-STAMP induction and intracellular distribution during osteoclastogenesis. Highlighted Article: Luman, an ER-resident transcription factor, regulates the multinucleation of osteoclasts by promoting cell fusion of mononuclear osteoclasts through DC-STAMP induction and transportation during osteoclastogenesis.
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Affiliation(s)
- Soshi Kanemoto
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Yasuhiro Kobayashi
- Institute for Oral Science, Matsumoto Dental University, 1780 Gobara, Hiro-oka, Shiojiri, Nagano 399-0781, Japan
| | - Teruhito Yamashita
- Institute for Oral Science, Matsumoto Dental University, 1780 Gobara, Hiro-oka, Shiojiri, Nagano 399-0781, Japan
| | - Takeshi Miyamoto
- Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Min Cui
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Rie Asada
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Xiang Cui
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Kenta Hino
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Masayuki Kaneko
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Tomoko Takai
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Koji Matsuhisa
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Naoyuki Takahashi
- Institute for Oral Science, Matsumoto Dental University, 1780 Gobara, Hiro-oka, Shiojiri, Nagano 399-0781, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
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91
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92
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Wang B, Yan YW, Zhou Q, Gui SY, Chen FH, Wang Y. A novel all-trans retinoid acid derivative induces apoptosis in MDA-MB-231 breast cancer cells. Asian Pac J Cancer Prev 2015; 15:10819-24. [PMID: 25605183 DOI: 10.7314/apjcp.2014.15.24.10819] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AIMS To explore the effect and probable mechanism of a synthetic retinoid 4-amino-2-tri-fluoromethyl- phenyl ester (ATPR) on apoptosis of MDA-MB-231 breast cancer cells. MATERIALS AND METHODS MTT assays were performed to measure the proliferation of MDA-MB-231 cells treated with different concentrations of all- trans retinoic acid (ATRA) and ATPR. Morphologic changes were observed by microscopy. The apoptosis rates and cell cycling of MDA-MB-231 cells treated with ATRA or ATPR were assessed using flow cytometry analysis. Expression of retinoic acid receptor and phosphorylation of ERK, JNK, p38 proteins were detected by Western blotting. RESULTS Treatment of the cells with the addition of 15 μmol/L ATPR for 48 h clearly demonstrated reduced cell numbers and deformed cells, whereas no changes in the number and morphology were observed after treatment with ATRA. The apoptosis rate was 33.2% after breast cancer MDA-MB-231 cells were treated by ATPR (15 μmol/L) whereas ATRA (15 μmol/L) had no apoptotic effect. ATPR inhibited the phosphorylation of ERK, JNK, and p38 while ATRA had no significant effect. ATPR inhibited the expression of BiP and increased the expression of Chop at the protein level compared with control groups, ATRA and ATPR both decreased the protein expression of RXR α, ATPR reduced the protein expression of RARβ and RXRβ while ATRA did not decrease RARβ or RXRβ. CONCLUSIONS ATPR could induce apoptosis of breast cancer MDA-MB-231 cells, possible mechanisms being binding to RARβ/RXRβ heterodimers, then activation of ER stress involving the MAPK pathway.
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Affiliation(s)
- Bei Wang
- Department of Pathology and Pathophysiology, medical School, Southeast University, Nanjing, Jiangsu, China E-mail : ,
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93
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Abstract
Stress induced by accumulation of misfolded proteins in the endoplasmic reticulum is observed in many physiological and pathological conditions. To cope with endoplasmic reticulum stress, cells activate the unfolded protein response, a dynamic signalling network that orchestrates the recovery of homeostasis or triggers apoptosis, depending on the level of damage. Here we provide an overview of recent insights into the mechanisms that cells employ to maintain proteostasis and how the unfolded protein response determines cell fate under endoplasmic reticulum stress.
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94
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XBP1-Independent UPR Pathways Suppress C/EBP-β Mediated Chondrocyte Differentiation in ER-Stress Related Skeletal Disease. PLoS Genet 2015; 11:e1005505. [PMID: 26372225 PMCID: PMC4651170 DOI: 10.1371/journal.pgen.1005505] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/14/2015] [Indexed: 12/20/2022] Open
Abstract
Schmid metaphyseal chondrodysplasia (MCDS) involves dwarfism and growth plate cartilage hypertrophic zone expansion resulting from dominant mutations in the hypertrophic zone collagen, Col10a1. Mouse models phenocopying MCDS through the expression of an exogenous misfolding protein in the endoplasmic reticulum (ER) in hypertrophic chondrocytes have demonstrated the central importance of ER stress in the pathology of MCDS. The resultant unfolded protein response (UPR) in affected chondrocytes involved activation of canonical ER stress sensors, IRE1, ATF6, and PERK with the downstream effect of disrupted chondrocyte differentiation. Here, we investigated the role of the highly conserved IRE1/XBP1 pathway in the pathology of MCDS. Mice with a MCDS collagen X p.N617K knock-in mutation (ColXN617K) were crossed with mice in which Xbp1 was inactivated specifically in cartilage (Xbp1CartΔEx2), generating the compound mutant, C/X. The severity of dwarfism and hypertrophic zone expansion in C/X did not differ significantly from ColXN617K, revealing surprising redundancy for the IRE1/XBP1 UPR pathway in the pathology of MCDS. Transcriptomic analyses of hypertrophic zone cartilage identified differentially expressed gene cohorts in MCDS that are pathologically relevant (XBP1-independent) or pathologically redundant (XBP1-dependent). XBP1-independent gene expression changes included large-scale transcriptional attenuation of genes encoding secreted proteins and disrupted differentiation from proliferative to hypertrophic chondrocytes. Moreover, these changes were consistent with disruption of C/EBP-β, a master regulator of chondrocyte differentiation, by CHOP, a transcription factor downstream of PERK that inhibits C/EBP proteins, and down-regulation of C/EBP-β transcriptional co-factors, GADD45-β and RUNX2. Thus we propose that the pathology of MCDS is underpinned by XBP1 independent UPR-induced dysregulation of C/EBP-β-mediated chondrocyte differentiation. Our data suggest that modulation of C/EBP-β activity in MCDS chondrocytes may offer therapeutic opportunities. A significant component of the molecular pathology of many inherited skeletal disorders caused by mutations that cause misfolding and intracellular retention of extracellular matrix proteins is the induction of a cellular response to endoplasmic reticulum stress called the unfolded protein response (UPR). In the case of Schmid metaphyseal chondrodysplasia (MCDS) caused by collagen X misfolding mutations, the consequences of the UPR have been shown to be the central cause of the cartilage pathology. Thus understanding the involvement of canonical UPR sensors, IRE1, ATF6, and PERK and their downstream signalling effects on chondrocyte differentiation and function is important for defining disease mechanisms and devising new therapies. Using a mouse model expressing misfolding collagen X and lacking IRE1/XBP1 pathway activity in chondrocytes, we demonstrate that this highly conserved UPR pathway is redundant to the cartilage pathology thus implicating XBP1-independent UPR signalling pathways. Based on detailed analysis of gene expression patterns we propose that XBP1-independent UPR driven disruption of C/EBP-β, a master regulator of chondrocyte differentiation, is important for the pathophysiology. Strategies designed to modulate C/EBP-β activity may thus offer therapeutic opportunities.
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95
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Ashraf NU, Sheikh TA. Endoplasmic reticulum stress and Oxidative stress in the pathogenesis of Non-alcoholic fatty liver disease. Free Radic Res 2015. [PMID: 26223319 DOI: 10.3109/10715762.2015.1078461] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. The underlying causes of the disease progression in NAFLD are unclear. Recent evidences suggest endoplasmic reticulum stress in the development of lipid droplets (steatosis) and subsequent generation of reactive oxygen species (ROS) in the progression to non-alcoholic steatohepatitis (NASH). The signalling pathway activated by disruption of endoplasmic reticulum (ER) homoeostasis, called as unfolded protein response, is linked with membrane biosynthesis, insulin action, inflammation and apoptosis. ROS are important mediators of inflammation. Protein folding in ER is linked to ROS. Therefore understanding the basic mechanisms that lead to ER stress and ROS in NAFLD have become the topics of immense interest. The present review focuses on the role of ER stress and ROS in the pathogenesis of NAFLD. We also highlight the cross talk between ER stress and oxidative stress which suggest and encourage the development of therapeutics for NAFLD. Further we have reviewed various strategies used for the management of NAFLD/NASH and limitations of such strategies. Our review therefore highlights the need for newer strategies with regards to ER stress and oxidative stress.
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Affiliation(s)
- N U Ashraf
- a Academy of Scientific and Innovative Research (AcSIR) , New Delhi , India.,b PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine , Canal Road, Jammu Tawi , Jammu and Kashmir , India
| | - T A Sheikh
- a Academy of Scientific and Innovative Research (AcSIR) , New Delhi , India.,b PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine , Canal Road, Jammu Tawi , Jammu and Kashmir , India
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96
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Rose M, Schubert C, Dierichs L, Gaisa NT, Heer M, Heidenreich A, Knüchel R, Dahl E. OASIS/CREB3L1 is epigenetically silenced in human bladder cancer facilitating tumor cell spreading and migration in vitro. Epigenetics 2015; 9:1626-40. [PMID: 25625847 DOI: 10.4161/15592294.2014.988052] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
CREB3L1 has been recently proposed as a novel metastasis suppressor gene in breast cancer. Our current study highlights CREB3L1 expression, regulation, and function in bladder cancer. We demonstrate a significant downregulation of CREB3L1 mRNA expression (n = 64) in primary bladder cancer tissues caused by tumor-specific CREB3L1 promoter hypermethylation (n = 51). Based on pyrosequencing CREB3L1 methylation was shown to be potentially associated with a more aggressive phenotype of bladder cancer. These findings were verified by an independent public data set containing data from 184 bladder tumors. In addition, immunohistochemical evaluation showed that CREB3L1 protein expression is decreased in bladder cancer tissues as well. Interestingly, protein loss is predominately observed in the nuclei of aggressive tumor cells. Based on in vitro models we clearly show that CREB3L1 re-expression mediates suppression of tumor cell migration and colony growth of high grade and invasive bladder cancer cells. The candidate tumor suppressor and TGF-β signaling inhibitor HTRA3 was furthermore identified as putative target gene of CREB3L1 in both invasive J82 bladder cells and primary bladder tumors. Hence, our data provide for the first time evidence that the transcription factor CREB3L1 may have an important role as a putative tumor suppressor in bladder cancer.
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Key Words
- ATCC, American Type Culture Collection
- BMP-2, bone morphogenetic protein 2
- CA, California
- CIS, Carcinoma in situ
- CREB3L1, element binding protein 3-like 1
- DAB, 3-3′ diaminobenzidine
- DAC, 5-aza-2′-deoxycytidine
- DNA, desoxyribonucleic acid
- EK, ethics committee
- ER, endoplasmic reticulum
- FC, fold change
- FFPE, formalin fixed paraffin embedded
- G1, well differentiated
- G2, moderately differentiated
- G3, poorly differentiated
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- HCV, Hepatitis C virus
- HPV, human papilloma virus
- HTRA (1-4), high-temperature requirement factor A (1-4)
- HTRA3
- IQR, interquartile range
- IRS, immunoreactive score
- LMU, Ludwig-Maximilians-University
- M, methylated
- MIBC, muscle invasive bladder cancer
- MSP, methylation specific PCR
- NMIBC, non-muscle invasive bladder cancer
- NU, normal urothelium
- OASIS / CREB3L1
- OASIS, old astrocyte specifically-induced substance
- PCR, polymerase chain reaction
- RIP, regulated intramembrane proteolysis
- RWTH, Rheinisch Westfälisch Technische Hochschule
- SP1, site 1 protease
- SP2, site 2 protease
- TCGA, The Cancer Genome Atlas
- TGF-β, transforming growth factor beta
- TSA, trichostatin A
- TSS, transcription start site
- U, unmethylated
- UC, urothelial cell cancer
- UPR, unfold protein response
- USA, United States of America
- WHO, World Health Organization
- WI, Wisconsin
- bladder cancer
- cDNA, copy number desoxyribonucleic acid
- mRNA, messenger ribo nucleic acid
- n, number
- ns, not significant
- pTa, papillary non-invasive tumors
- promoter methylation
- s.e.m., standard error of the margin
- tumor cell migration
- tumor suppressor gene
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Affiliation(s)
- Michael Rose
- a Molecular Oncology Group; Institute of Pathology ; RWTH Aachen University ; Aachen , Germany
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97
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Chevet E, Hetz C, Samali A. Endoplasmic reticulum stress-activated cell reprogramming in oncogenesis. Cancer Discov 2015; 5:586-97. [PMID: 25977222 DOI: 10.1158/2159-8290.cd-14-1490] [Citation(s) in RCA: 271] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/28/2015] [Indexed: 12/29/2022]
Abstract
UNLABELLED Stress induced by the accumulation of unfolded proteins in the endoplasmic reticulum (ER) is observed in many human diseases, including cancers. Cellular adaptation to ER stress is mediated by the unfolded protein response (UPR), which aims at restoring ER homeostasis. The UPR has emerged as a major pathway in remodeling cancer gene expression, thereby either preventing cell transformation or providing an advantage to transformed cells. UPR sensors are highly regulated by the formation of dynamic protein scaffolds, leading to integrated reprogramming of the cells. Herein, we describe the regulatory mechanisms underlying UPR signaling upon cell intrinsic or extrinsic challenges, and how they engage cell transformation programs and/or provide advantages to cancer cells, leading to enhanced aggressiveness or chemoresistance. We discuss the emerging cross-talk between the UPR and related metabolic processes to ensure maintenance of protein homeostasis and its impact on cell transformation and tumor growth. SIGNIFICANCE ER stress signaling is dysregulated in many forms of cancer and contributes to tumor growth as a survival factor, in addition to modulating other disease-associated processes, including cell migration, cell transformation, and angiogenesis. Evidence for targeting the ER stress signaling pathway as an anticancer strategy is compelling, and novel agents that selectively inhibit the UPR have demonstrated preliminary evidence of preclinical efficacy with an acceptable safety profile.
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Affiliation(s)
- Eric Chevet
- Oncogenesis, Stress, Cancer, University of Rennes, Rennes, France. Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Santiago, Chile. Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts.
| | - Afshin Samali
- Apoptosis Research Centre, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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98
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Activation of hepatic CREBH and Insig signaling in the anti-hypertriglyceridemic mechanism of R-α-lipoic acid. J Nutr Biochem 2015; 26:921-8. [PMID: 26007286 DOI: 10.1016/j.jnutbio.2015.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/15/2015] [Accepted: 03/24/2015] [Indexed: 12/12/2022]
Abstract
The activation of sterol regulatory element binding proteins (SREBPs) is regulated by insulin-induced genes 1 and 2 (Insig-1 and Insig-2) and SCAP. We previously reported that feeding R-α-lipoic acid (LA) to Zucker diabetic fatty (ZDF) rats improves severe hypertriglyceridemia. In this study, we investigated the role of cyclic AMP-responsive element binding protein H (CREBH) in the lipid-lowering mechanism of LA and its involvement in the SREBP-1c and Insig pathway. Incubation of McA cells with LA (0.2 mM) or glucose (6 mM) stimulated activation of CREBH. LA treatment further induced mRNA expression of Insig-1 and Insig-2a, but not Insig-2b, in glucose-treated cells. In vivo, feeding LA to obesity-induced hyperlipidemic ZDF rats activated hepatic CREBH and stimulated transcription and translation of Insig-1 and Insig-2a. Activation of CREBH and Insigs induced by LA suppressed processing of SREBP-1c precursor into nuclear SREBP-1c, which subsequently inhibited expression of genes involved in fatty acid synthesis, including FASN, ACC and SCD-1, and reduced triglyceride (TG) contents in both glucose-treated cells and ZDF rat livers. Additionally, LA treatment also decreased abundances of very low density lipoprotein (VLDL)-associated apolipoproteins, apoB100 and apoE, in glucose-treated cells and livers of ZDF rats, leading to decreased secretion of VLDL and improvement of hypertriglyceridemia. This study unveils a novel molecular mechanism whereby LA lowers TG via activation of hepatic CREBH and increased expression of Insig-1 and Insig-2a to inhibit de novo lipogenesis and VLDL secretion. These findings provide novel insight into the therapeutic potential of LA as an anti-hypertriglyceridemia dietary molecule.
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99
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Greenwood M, Greenwood MP, Paton JFR, Murphy D. Transcription Factor CREB3L1 Regulates Endoplasmic Reticulum Stress Response Genes in the Osmotically Challenged Rat Hypothalamus. PLoS One 2015; 10:e0124956. [PMID: 25915053 PMCID: PMC4411032 DOI: 10.1371/journal.pone.0124956] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 03/19/2015] [Indexed: 11/18/2022] Open
Abstract
Arginine vasopressin (AVP) is synthesised in magnocellular neurons (MCNs) of supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus. In response to the hyperosmotic stressors of dehydration (complete fluid deprivation, DH) or salt loading (drinking 2% salt solution, SL), AVP synthesis increases in MCNs, which over-burdens the protein folding machinery in the endoplasmic reticulum (ER). ER stress and the unfolded protein response (UPR) are signaling pathways that improve ER function in response to the accumulation of misfold/unfold protein. We asked whether an ER stress response was activated in the SON and PVN of DH and SL rats. We observed increased mRNA expression for the immunoglobulin heavy chain binding protein (BiP), activating transcription factor 4 (Atf4), C/EBP-homologous protein (Chop), and cAMP responsive element binding protein 3 like 1 (Creb3l1) in both SON and PVN of DH and SL rats. Although we found no changes in the splicing pattern of X box-binding protein 1 (Xbp1), an increase in the level of the unspliced form of Xbp1 (Xbp1U) was observed in DH and SL rats. CREB3L1, a novel ER stress inducer, has been shown to be activated by ER stress to regulate the expression of target genes. We have previously shown that CREB3L1 is a transcriptional regulator of the AVP gene; however, a role for CREB3L1 in the response to ER stress has yet to be investigated in MCNs. Here, we used lentiviral vectors to introduce a dominant negative form of CREB3L1 (CREB3L1DN) in the rat SON. Expression of CREB3L1DN in the SON decreased Chop and Xbp1U mRNA levels, but not BiP and Atf4 transcript expression. CREB3L1 is thus implicated as a transcriptional mediator of the ER stress response in the osmotically stimulated SON.
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Affiliation(s)
- Mingkwan Greenwood
- School of Clinical Sciences, University of Bristol, Bristol, England
- * E-mail:
| | | | - Julian F. R. Paton
- School of Physiology and Pharmacology, University of Bristol, Bristol, England
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, England
- Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia
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HBx induces the proliferation of hepatocellular carcinoma cells via AP1 over-expressed as a result of ER stress. Biochem J 2015; 466:115-21. [PMID: 25428452 DOI: 10.1042/bj20140819] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and chronic hepatitis B virus (HBV) infection is the most common risk factor for HCC. The HBV proteins can induce oncogenic or synergy effects with a hyperproliferative response on transformation into HCC. CREBH (cAMP-responsive, element-binding protein H), activated by stress in the endoplasmic reticulum (ER), is an ER-resident transmembrane bZIP (basic leucine zipper) transcription factor that is specifically expressed in the liver. In the present study, we address the role played by CREBH activated by ER stress in HBV-induced hepatic cell proliferation. We confirmed CREBH activation by ER stress and showed that it occurred as a result of/via hepatitis B virus X (HBx)-induced ER stress. CREBH activated by HBx increased the expression of AP-1 target genes through c-Jun induction. Under pathological conditions such as liver damage or liver regeneration, activated CREBH may have an important role to play in hepatic inflammation and cell proliferation, as an insulin receptor with dual functions under these conditions. We showed that CREBH activated by HBx interacted with HBx protein, leading to a synergistic effect on the expression of AP-1 target genes and the proliferation of HCC cells and mouse primary hepatocytes. In conclusion, in HBV-infected hepatic cells or patients with chronic HBV, CREBH may induce proliferation of hepatic cells in co-operation with HBx, resulting in HCC.
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