1
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Huang D, Li Y, Han J, Zuo H, Liu H, Chen Z. Xbp1 promotes odontoblastic differentiation through modulating mitochondrial homeostasis. FASEB J 2024; 38:e23600. [PMID: 38572599 DOI: 10.1096/fj.202400186r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/05/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024]
Abstract
Odontoblast differentiation depends on the orderly recruitment of transcriptional factors (TFs) in the transcriptional regulatory network. The depletion of crucial TFs disturbs dynamic alteration of the chromatin landscape and gene expression profile, leading to developmental defects. Our previous studies have revealed that the basic leucine zipper (bZIP) TF family is crucial in odontoblastic differentiation, but the function of bZIP TF family member XBP1 is still unknown. Here, we showed the stage-specific expression patterns of the spliced form Xbp1s during tooth development. Elevated Xbp1 expression and nuclear translocation of XBP1S in mesenchymal stem cells (MSCs) were induced by differentiation medium in vitro. Diminution of Xbp1 expression impaired the odontogenic differentiation potential of MSCs. The further integration of ATAC-seq and RNA-seq identified Hspa9 as a direct downstream target, an essential mitochondrial chaperonin gene that modulated mitochondrial homeostasis. The amelioration of mitochondrial dysfunction rescued the impaired odontogenic differentiation potential of MSCs caused by the diminution of Xbp1. Furthermore, the overexpression of Hspa9 rescued Xbp1-deficient defects in odontoblastic differentiation. Our study illustrates the crucial role of Xbp1 in odontoblastic differentiation via modulating mitochondrial homeostasis and brings evidence to the therapy of mitochondrial diseases caused by genetic defects.
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Affiliation(s)
- Delan Huang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yuanyuan Li
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Jiahao Han
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Huanyan Zuo
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Cariology and Endodontics, School of Stomatology, Wuhan University, Wuhan, China
| | - Huan Liu
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Periodontology, School of Stomatology, Wuhan University, Wuhan, China
- TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Zhi Chen
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Cariology and Endodontics, School of Stomatology, Wuhan University, Wuhan, China
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2
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Systematic identification of cell-fate regulatory programs using a single-cell atlas of mouse development. Nat Genet 2022; 54:1051-1061. [PMID: 35817981 DOI: 10.1038/s41588-022-01118-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 06/01/2022] [Indexed: 12/21/2022]
Abstract
Waddington's epigenetic landscape is a metaphor frequently used to illustrate cell differentiation. Recent advances in single-cell genomics are altering our understanding of the Waddington landscape, yet the molecular mechanisms of cell-fate decisions remain poorly understood. We constructed a cell landscape of mouse lineage differentiation during development at the single-cell level and described both lineage-common and lineage-specific regulatory programs during cell-type maturation. We also found lineage-common regulatory programs that are broadly active during the development of invertebrates and vertebrates. In particular, we identified Xbp1 as an evolutionarily conserved regulator of cell-fate determinations across different species. We demonstrated that Xbp1 transcriptional regulation is important for the stabilization of the gene-regulatory networks for a wide range of mouse cell types. Our results offer genetic and molecular insights into cellular gene-regulatory programs and will serve as a basis for further advancing the understanding of cell-fate decisions.
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3
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Kaur N, Raja R, Ruiz-Velasco A, Liu W. Cellular Protein Quality Control in Diabetic Cardiomyopathy: From Bench to Bedside. Front Cardiovasc Med 2020; 7:585309. [PMID: 33195472 PMCID: PMC7593653 DOI: 10.3389/fcvm.2020.585309] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/09/2020] [Indexed: 12/14/2022] Open
Abstract
Heart failure is a serious comorbidity and the most common cause of mortality in diabetes patients. Diabetic cardiomyopathy (DCM) features impaired cellular structure and function, culminating in heart failure; however, there is a dearth of specific clinical therapy for treating DCM. Protein homeostasis is pivotal for the maintenance of cellular viability under physiological and pathological conditions, particularly in the irreplaceable cardiomyocytes; therefore, it is tightly regulated by a protein quality control (PQC) system. Three evolutionarily conserved molecular processes, the unfolded protein response (UPR), the ubiquitin-proteasome system (UPS), and autophagy, enhance protein turnover and preserve protein homeostasis by suppressing protein translation, degrading misfolded or unfolded proteins in cytosol or organelles, disposing of damaged and toxic proteins, recycling essential amino acids, and eliminating insoluble protein aggregates. In response to increased cellular protein demand under pathological insults, including the diabetic condition, a coordinated PQC system retains cardiac protein homeostasis and heart performance, on the contrary, inappropriate PQC function exaggerates cardiac proteotoxicity with subsequent heart dysfunction. Further investigation of the PQC mechanisms in diabetes propels a more comprehensive understanding of the molecular pathogenesis of DCM and opens new prospective treatment strategies for heart disease and heart failure in diabetes patients. In this review, the function and regulation of cardiac PQC machinery in diabetes mellitus, and the therapeutic potential for the diabetic heart are discussed.
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Affiliation(s)
- Namrita Kaur
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, United Kingdom
| | - Rida Raja
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, United Kingdom
| | - Andrea Ruiz-Velasco
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, United Kingdom
| | - Wei Liu
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, United Kingdom
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4
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Nakata T, Hirano Y, Katsumata H, Tokita R, Yagi T, Toyoshima Y, Minami S. Growth hormone activates X-box binding protein 1 in a sexually dimorphic manner through the extracellular signal-regulated protein kinase and CCAAT/enhancer-binding protein β pathway in rat liver. Endocr J 2020; 67:185-200. [PMID: 31748431 DOI: 10.1507/endocrj.ej19-0240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Growth hormone (GH) has multiple physiological roles, acting on many organs. In order to investigate its roles in rat liver, we tried to identify novel genes whose transcription was regulated by GH. We identified X-box binding protein 1 (Xbp1) as a candidate gene. XBP1 is a key transcription factor activated in response to endoplasmic reticulum (ER) stress. The purpose of this study was to investigate the mode of action of GH on XBP1, including the relation with ER stress, sex-dependent expression of the mRNA, and the signaling pathway. Intravenous administration of GH rapidly and transiently increased Xbp1 mRNA in hypophysectomized rat livers. Neither phosphorylated inositol-requiring-1α (IRE1α) nor phosphorylated PKR-like ER kinase (PERK) increased, suggesting that Xbp1 expression is induced by an ER stress-independent mechanism. The active form of XBP1(S) protein was increased by GH administration and was followed by an increased ER-associated dnaJ protein 4 (ERdj4) mRNA level. XBP1(S) protein levels were predominantly identified in male rat livers with variations among individuals similar to those of phosphorylated signal transducer and activator of transcription 5B (STAT5B), suggesting that XBP1(S) protein levels are regulated by the sex-dependent secretary pattern of GH. The GH signaling pathway to induce Xbp1 mRNA was examined in rat hepatoma H4IIE cells. GH induced the phosphorylation of CCAAT/enhancer-binding protein β (C/EBPβ) following extracellular signal-regulated protein kinase (ERK) phosphorylation. Taken together, the results indicated that XBP1 is activated by GH in rat liver in a sexually dimorphic manner via ERK and C/EBPβ pathway.
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Affiliation(s)
- Tomoko Nakata
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
| | - Yoshitaka Hirano
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
- Current Affiliation: Department of Nephrology, Nippon Medical School, Tokyo 113-8603, Japan
| | - Harumi Katsumata
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
| | - Reiko Tokita
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
| | - Takashi Yagi
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
| | - Yuka Toyoshima
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
| | - Shiro Minami
- Department of Bioregulation, Institute for Advanced Medical Sciences, Nippon Medical School, Kawasaki 211-8533, Japan
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5
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Yan B, Wang H, Tan Y, Fu W. microRNAs in Cardiovascular Disease: Small Molecules but Big Roles. Curr Top Med Chem 2019; 19:1918-1947. [PMID: 31393249 DOI: 10.2174/1568026619666190808160241] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/01/2019] [Accepted: 07/25/2019] [Indexed: 01/01/2023]
Abstract
microRNAs (miRNAs) are an evolutionarily conserved class of small single-stranded noncoding RNAs. The aberrant expression of specific miRNAs has been implicated in the development and progression of diverse cardiovascular diseases. For many decades, miRNA therapeutics has flourished, taking advantage of the fact that miRNAs can modulate gene expression and control cellular phenotypes at the posttranscriptional level. Genetic replacement or knockdown of target miRNAs by chemical molecules, referred to as miRNA mimics or inhibitors, has been used to reverse their abnormal expression as well as their adverse biological effects in vitro and in vivo in an effort to fully implement the therapeutic potential of miRNA-targeting treatment. However, the limitations of the chemical structure and delivery systems are hindering progress towards clinical translation. Here, we focus on the regulatory mechanisms and therapeutic trials of several representative miRNAs in the context of specific cardiovascular diseases; from this basic perspective, we evaluate chemical modifications and delivery vectors of miRNA-based chemical molecules and consider the underlying challenges of miRNA therapeutics as well as the clinical perspectives on their applications.
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Affiliation(s)
- Bingqian Yan
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Huijing Wang
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yao Tan
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Wei Fu
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Department of Pediatric Cardiothoracic Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Shanghai Key Laboratory of Tissue Engineering, Shanghai 9th People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China
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6
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Wang X, Deng Y, Zhang G, Li C, Ding G, May HI, Tran DH, Luo X, Jiang DS, Li DL, Wei X, Xu L, Ferdous A, Gillette TG, Scherer PE, Jiang X, Wang ZV. Spliced X-box Binding Protein 1 Stimulates Adaptive Growth Through Activation of mTOR. Circulation 2019; 140:566-579. [PMID: 31177839 DOI: 10.1161/circulationaha.118.038924] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The unfolded protein response plays versatile roles in physiology and pathophysiology. Its connection to cell growth, however, remains elusive. Here, we sought to define the role of unfolded protein response in the regulation of cardiomyocyte growth in the heart. METHODS We used both gain- and loss-of-function approaches to genetically manipulate XBP1s (spliced X-box binding protein 1), the most conserved signaling branch of the unfolded protein response, in the heart. In addition, primary cardiomyocyte culture was used to address the role of XBP1s in cell growth in a cell-autonomous manner. RESULTS We found that XBP1s expression is reduced in both human and rodent cardiac tissues under heart failure. Furthermore, deficiency of XBP1s leads to decompensation and exacerbation of heart failure progression under pressure overload. On the other hand, cardiac-restricted overexpression of XBP1s prevents the development of cardiac dysfunction. Mechanistically, we found that XBP1s stimulates adaptive cardiac growth through activation of the mechanistic target of rapamycin signaling, which is mediated via FKBP11 (FK506-binding protein 11), a novel transcriptional target of XBP1s. Moreover, silencing of FKBP11 significantly diminishes XBP1s-induced mechanistic target of rapamycin activation and adaptive cell growth. CONCLUSIONS Our results reveal a critical role of the XBP1s-FKBP11-mechanistic target of rapamycin axis in coupling of the unfolded protein response and cardiac cell growth regulation.
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Affiliation(s)
- Xiaoding Wang
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Yingfeng Deng
- Touchstone Diabetes Center (Y.D., P.E.S.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Guangyu Zhang
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Chao Li
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Guanqiao Ding
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Herman I May
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Diem H Tran
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Xiang Luo
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Ding-Sheng Jiang
- Division of Cardiothoracic and Vascular Surgery, Key Laboratory of Organ Transplantation of Ministry of Education and Key Laboratory of Organ Transplantation of Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China (D.-S.J., X. Wei)
| | - Dan L Li
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Xiang Wei
- Division of Cardiothoracic and Vascular Surgery, Key Laboratory of Organ Transplantation of Ministry of Education and Key Laboratory of Organ Transplantation of Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China (D.-S.J., X. Wei)
| | - Lin Xu
- Department of Cardiology, Renmin Hospital of Wuhan University, Hubei, China (L.X., X.J.)
| | - Anwarul Ferdous
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Thomas G Gillette
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Philipp E Scherer
- Touchstone Diabetes Center (Y.D., P.E.S.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Xuejun Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Hubei, China (L.X., X.J.)
| | - Zhao V Wang
- Division of Cardiology (X. Wang, G.Z., C.L., G.D., H.I.M., D.H.T., X.L., D.L.L., A.F., T.G.G., Z.V.W.), Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
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7
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Zhang G, Wang X, Gillette TG, Deng Y, Wang ZV. Unfolded Protein Response as a Therapeutic Target in Cardiovascular Disease. Curr Top Med Chem 2019; 19:1902-1917. [PMID: 31109279 PMCID: PMC7024549 DOI: 10.2174/1568026619666190521093049] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 04/09/2019] [Accepted: 05/02/2019] [Indexed: 12/15/2022]
Abstract
Cardiovascular disease is the leading cause of death worldwide. Despite overwhelming socioeconomic impact and mounting clinical needs, our understanding of the underlying pathophysiology remains incomplete. Multiple forms of cardiovascular disease involve an acute or chronic disturbance in cardiac myocytes, which may lead to potent activation of the Unfolded Protein Response (UPR), a cellular adaptive reaction to accommodate protein-folding stress. Accumulation of unfolded or misfolded proteins in the Endoplasmic Reticulum (ER) elicits three signaling branches of the UPR, which otherwise remain quiescent. This ER stress response then transiently suppresses global protein translation, augments production of protein-folding chaperones, and enhances ER-associated protein degradation, with an aim to restore cellular homeostasis. Ample evidence has established that the UPR is strongly induced in heart disease. Recently, the mechanisms of action and multiple pharmacological means to favorably modulate the UPR are emerging to curb the initiation and progression of cardiovascular disease. Here, we review the current understanding of the UPR in cardiovascular disease and discuss existing therapeutic explorations and future directions.
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Affiliation(s)
- Guangyu Zhang
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Xiaoding Wang
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Thomas G. Gillette
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Yingfeng Deng
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Zhao V. Wang
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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8
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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 2018; 286:241-278. [PMID: 30027602 PMCID: PMC7379631 DOI: 10.1111/febs.14608] [Citation(s) in RCA: 518] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [Abstract] [Key Words] [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 Centre, National University of Ireland, Galway, Ireland
| | - Antonio Carlesso
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Chetan Chintha
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | | | - Dimitrios Doultsinos
- INSERM U1242, University of Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Brian Leuzzi
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Andreia Luís
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Centre, Vienna, Austria
| | - Nicole McCarthy
- Institute for Experimental Cancer Research in Paediatrics, Goethe-University, Frankfurt, Germany
| | - Luigi Montibeller
- Neurogenetics Group, Division of Brain Sciences, Faculty of Medicine, Imperial College London, UK
| | - Sanket More
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, Belgium
| | - Alexandra Papaioannou
- INSERM U1242, University of Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Franziska Püschel
- Cell Death Regulation Group, Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Maria Livia Sassano
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, Belgium
| | - Josip Skoko
- Institute of Cell Biology and Immunology, University of Stuttgart, Germany
| | - Patrizia Agostinis
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, Belgium
| | - Jackie de Belleroche
- Neurogenetics Group, Division of Brain Sciences, Faculty of Medicine, Imperial College London, UK
| | - Leif A Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Simone Fulda
- Institute for Experimental Cancer Research in Paediatrics, Goethe-University, Frankfurt, Germany
| | - Adrienne M Gorman
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Sandra Healy
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Andrey Kozlov
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Centre, Vienna, Austria
| | - Cristina Muñoz-Pinedo
- Cell Death Regulation Group, Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Markus Rehm
- Institute of Cell Biology and Immunology, University of Stuttgart, Germany
| | - Eric Chevet
- INSERM U1242, University of Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Afshin Samali
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
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9
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Le NT, Martin JF, Fujiwara K, Abe JI. Sub-cellular localization specific SUMOylation in the heart. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2041-2055. [PMID: 28130202 DOI: 10.1016/j.bbadis.2017.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/21/2016] [Accepted: 01/09/2017] [Indexed: 12/27/2022]
Abstract
Although the majority of SUMO substrates are localized in the nucleus, SUMOylation is not limited to nuclear proteins and can be also detected in extra-nuclear proteins. In this review, we will highlight and discuss how SUMOylation in different cellular compartments regulate biological processes. First, we will discuss the key role of SUMOylation of proteins in the extra-nuclear compartment in cardiomyocytes, which is overwhelmingly cardio-protective. On the other hand, SUMOylation of nuclear proteins is generally detrimental to the cardiac function mainly because of the trans-repressive nature of SUMOylation on many transcription factors. We will also discuss the potential role of SUMOylation in epigenetic regulation. In this review, we will propose a new concept that shuttling of SUMO proteases between the nuclear and extra-nuclear compartments without changing their enzymatic activity regulates the extent of SUMOylation in these compartments and determines the response and fate of cardiomyocytes after cardiac insults. Approaches focused specifically to inhibit this shuttling in cardiomyocytes will be necessary to understand the whole picture of SUMOylation and its pathophysiological consequences in the heart, especially after cardiac insults. This article is part of a Special Issue entitled: Genetic and epigenetic control of heart failure - edited by Jun Ren & Megan Yingmei Zhang.
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Affiliation(s)
- Nhat-Tu Le
- Department of Cardiology - Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - James F Martin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Keigi Fujiwara
- Department of Cardiology - Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jun-Ichi Abe
- Department of Cardiology - Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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10
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Cissé M, Duplan E, Checler F. The transcription factor XBP1 in memory and cognition: Implications in Alzheimer disease. Mol Med 2017; 22:905-917. [PMID: 28079229 DOI: 10.2119/molmed.2016.00229] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/23/2016] [Indexed: 12/21/2022] Open
Abstract
X-box binding protein 1 (XBP1) is a unique basic region leucine zipper transcription factor isolated two decades ago in a search for regulators of major histocompatibility complex class II gene expression. XBP1 is a very complex protein regulating many physiological functions, including immune system, inflammatory responses, and lipid metabolism. Evidence over the past few years suggests that XBP1 also plays important roles in pathological settings since its activity as transcription factor has profound effects on the prognosis and progression of diseases such as cancer, neurodegeneration, and diabetes. Here we provide an overview on recent advances in our understanding of this multifaceted molecule, particularly in regulating synaptic plasticity and memory function, and the implications in neurodegenerative diseases with emphasis on Alzheimer disease.
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Affiliation(s)
- Moustapha Cissé
- Université Côte d'Azur, INSERM, CNRS, IPMC, team labeled "Fondation pour la Recherche Médicale" and "Laboratory of Excellence (LABEX) Distalz", 660 route des Lucioles, 06560, Sophia-Antipolis, Valbonne, France
| | - Eric Duplan
- Université Côte d'Azur, INSERM, CNRS, IPMC, team labeled "Fondation pour la Recherche Médicale" and "Laboratory of Excellence (LABEX) Distalz", 660 route des Lucioles, 06560, Sophia-Antipolis, Valbonne, France
| | - Frédéric Checler
- Université Côte d'Azur, INSERM, CNRS, IPMC, team labeled "Fondation pour la Recherche Médicale" and "Laboratory of Excellence (LABEX) Distalz", 660 route des Lucioles, 06560, Sophia-Antipolis, Valbonne, France
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11
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Liu M, Dudley SC. Role for the Unfolded Protein Response in Heart Disease and Cardiac Arrhythmias. Int J Mol Sci 2015; 17:ijms17010052. [PMID: 26729106 PMCID: PMC4730297 DOI: 10.3390/ijms17010052] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 12/14/2015] [Accepted: 12/16/2015] [Indexed: 12/23/2022] Open
Abstract
The unfolded protein response (UPR) has been extensively investigated in neurological diseases and diabetes, while its function in heart disease is less well understood. Activated UPR participates in multiple cardiac conditions and can either protect or impair heart function. Recently, the UPR has been found to play a role in arrhythmogenesis during human heart failure by affecting cardiac ion channels expression, and blocking UPR has an antiarrhythmic effect. This review will discuss the rationale for and challenges to targeting UPR in heart disease for treatment of arrhythmias.
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Affiliation(s)
- Man Liu
- The Warren Alpert Medical School of Brown University, Lifespan Cardiovascular Institute, the Providence VA Medical Center, 593 Eddy Street, APC814, Providence, RI 02903, USA.
| | - Samuel C Dudley
- The Warren Alpert Medical School of Brown University, Lifespan Cardiovascular Institute, the Providence VA Medical Center, 593 Eddy Street, APC814, Providence, RI 02903, USA.
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12
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Dunys J, Duplan E, Checler F. The transcription factor X-box binding protein-1 in neurodegenerative diseases. Mol Neurodegener 2014; 9:35. [PMID: 25216759 PMCID: PMC4166022 DOI: 10.1186/1750-1326-9-35] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 08/14/2014] [Indexed: 12/12/2022] Open
Abstract
Endoplasmic reticulum (ER) is the cellular compartment where secreted and integral membrane proteins are folded and matured. The accumulation of unfolded or misfolded proteins triggers a stress that is physiologically controlled by an adaptative protective response called Unfolded Protein Response (UPR). UPR is primordial to induce a quality control response and to restore ER homeostasis. When this adaptative response is defective, protein aggregates overwhelm cells and affect, among other mechanisms, synaptic function, signaling transduction and cell survival. Such dysfunction likely contributes to several neurodegenerative diseases that are indeed characterized by exacerbated protein aggregation, protein folding impairment, increased ER stress and UPR activation. This review briefly documents various aspects of the biology of the transcription factor XBP-1 (X-box Binding Protein-1) and summarizes recent findings concerning its putative contribution to the altered UPR response observed in various neurodegenerative disorders including Parkinson’s and Alzheimer’s diseases.
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Affiliation(s)
| | | | - Frédéric Checler
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275 CNRS-UNS, Sophia Antipolis, Nice, Valbonne F-06560, France.
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13
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Rabhi N, Salas E, Froguel P, Annicotte JS. Role of the unfolded protein response in β cell compensation and failure during diabetes. J Diabetes Res 2014; 2014:795171. [PMID: 24812634 PMCID: PMC4000654 DOI: 10.1155/2014/795171] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/12/2014] [Accepted: 03/13/2014] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β cell failure leads to diabetes development. During disease progression, β cells adapt their secretory capacity to compensate the elevated glycaemia and the peripheral insulin resistance. This compensatory mechanism involves a fine-tuned regulation to modulate the endoplasmic reticulum (ER) capacity and quality control to prevent unfolded proinsulin accumulation, a major protein synthetized within the β cell. These signalling pathways are collectively termed unfolded protein response (UPR). The UPR machinery is required to preserve ER homeostasis and β cell integrity. Moreover, UPR actors play a key role by regulating ER folding capacity, increasing the degradation of misfolded proteins, and limiting the mRNA translation rate. Recent genetic and biochemical studies on mouse models and human UPR sensor mutations demonstrate a clear requirement of the UPR machinery to prevent β cell failure and increase β cell mass and adaptation throughout the progression of diabetes. In this review we will highlight the specific role of UPR actors in β cell compensation and failure during diabetes.
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Affiliation(s)
- Nabil Rabhi
- European Genomic Institute for Diabetes (EGID), CNRS UMR 8199, Lille 2 University of Health and Law, 59000 Lille, France
| | - Elisabet Salas
- European Genomic Institute for Diabetes (EGID), CNRS UMR 8199, Lille 2 University of Health and Law, 59000 Lille, France
| | - Philippe Froguel
- European Genomic Institute for Diabetes (EGID), CNRS UMR 8199, Lille 2 University of Health and Law, 59000 Lille, France
- Departments of Genomics of Common Disease, Hammersmith Hospital, Imperial College London, London, UK
| | - Jean-Sébastien Annicotte
- European Genomic Institute for Diabetes (EGID), CNRS UMR 8199, Lille 2 University of Health and Law, 59000 Lille, France
- Laboratoire Bases Moléculaires et Modélisation du Diabète et de l'Obésité, Faculté de Médecine, Pôle Recherche, 59045 Lille, France
- *Jean-Sébastien Annicotte:
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14
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Abstract
The endoplasmic reticulum (ER) is a central organelle for protein biosynthesis, folding, and traffic. Perturbations in ER homeostasis create a condition termed ER stress and lead to activation of the complex signaling cascade called the unfolded protein response (UPR). Recent studies have documented that the UPR coordinates multiple signaling pathways and controls various physiologies in cells and the whole organism. Furthermore, unresolved ER stress has been implicated in a variety of metabolic disorders, such as obesity and type 2 diabetes. Therefore, intervening in ER stress and modulating signaling components of the UPR would provide promising therapeutics for the treatment of human metabolic diseases.
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Affiliation(s)
- Jaemin Lee
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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15
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Valentine CD, Anderson MO, Papa FR, Haggie PM. X-box binding protein 1 (XBP1s) is a critical determinant of Pseudomonas aeruginosa homoserine lactone-mediated apoptosis. PLoS Pathog 2013; 9:e1003576. [PMID: 23990788 PMCID: PMC3749957 DOI: 10.1371/journal.ppat.1003576] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 07/06/2013] [Indexed: 12/22/2022] Open
Abstract
Pseudomonas aeruginosa infections are associated with high mortality rates and occur in diverse conditions including pneumonias, cystic fibrosis and neutropenia. Quorum sensing, mediated by small molecules including N-(3-oxo-dodecanoyl) homoserine lactone (C12), regulates P. aeruginosa growth and virulence. In addition, host cell recognition of C12 initiates multiple signalling responses including cell death. To gain insight into mechanisms of C12-mediated cytotoxicity, we studied the role of endoplasmic reticulum stress in host cell responses to C12. Dramatic protection against C12-mediated cell death was observed in cells that do not produce the X-box binding protein 1 transcription factor (XBP1s). The leucine zipper and transcriptional activation motifs of XBP1s were sufficient to restore C12-induced caspase activation in XBP1s-deficient cells, although this polypeptide was not transcriptionally active. The XBP1s polypeptide also regulated caspase activation in cells stimulated with N-(3-oxo-tetradecanoyl) homoserine lactone (C14), produced by Yersinia enterolitica and Burkholderia pseudomallei, and enhanced homoserine lactone-mediated caspase activation in the presence of endogenous XBP1s. In C12-tolerant cells, responses to C12 including phosphorylation of p38 MAPK and eukaryotic initiation factor 2α were conserved, suggesting that C12 cytotoxicity is not heavily dependent on these pathways. In summary, this study reveals a novel and unconventional role for XBP1s in regulating host cell cytotoxic responses to bacterial acyl homoserine lactones. Chronic and acute infections associated with P. aeruginosa constitute a major healthcare burden. Antimicrobial approaches are currently used against P. aeruginosa; however, infections are typically refractory to treatment and drug resistant strains have been isolated. As such, there is urgent need to understand mechanisms of P. aeruginosa virulence and for new strategies to fight infections. The P. aeruginosa-derived quorum-sensing molecule C12 is recognized by host cells and initiates stress responses including cytotoxicity. In this study, the X-box binding protein 1 transcription factor (XBP1s) was identified as a host factor critical for apoptotic responses initiated by C12 and other similar quorum sensing molecules. Additional C12-initiated host responses, including phosphorylation of p38 MAPK and eIF2α were found to be of lesser importance for C12-initiated cytotoxicity. These studies have broad implications for our understanding of bacterial virulence mechanisms and for development of potential new strategies to combat infections.
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Affiliation(s)
- Cathleen D. Valentine
- Department of Nephrology, University of California, San Francisco, San Francisco, California, United States of America
| | - Marc O. Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California, United States of America
| | - Feroz R. Papa
- Lung Biology Center, Diabetes Center, and California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California, United States of America
| | - Peter M. Haggie
- Department of Nephrology, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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16
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Kadowaki H, Nishitoh H. Signaling pathways from the endoplasmic reticulum and their roles in disease. Genes (Basel) 2013; 4:306-33. [PMID: 24705207 PMCID: PMC3924831 DOI: 10.3390/genes4030306] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/01/2013] [Accepted: 05/14/2013] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is an organelle in which newly synthesized secretory and transmembrane proteins are assembled and folded into their correct tertiary structures. However, many of these ER proteins are misfolded as a result of various stimuli and gene mutations. The accumulation of misfolded proteins disrupts the function of the ER and induces ER stress. Eukaryotic cells possess a highly conserved signaling pathway, termed the unfolded protein response (UPR), to adapt and respond to ER stress conditions, thereby promoting cell survival. However, in the case of prolonged ER stress or UPR malfunction, apoptosis signaling is activated. Dysfunction of the UPR causes numerous conformational diseases, including neurodegenerative disease, metabolic disease, inflammatory disease, diabetes mellitus, cancer, and cardiovascular disease. Thus, ER stress-induced signaling pathways may serve as potent therapeutic targets of ER stress-related diseases. In this review, we will discuss the molecular mechanisms of the UPR and ER stress-induced apoptosis, as well as the possible roles of ER stress in several diseases.
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Affiliation(s)
- Hisae Kadowaki
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
| | - Hideki Nishitoh
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
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17
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Potential for therapeutic manipulation of the UPR in disease. Semin Immunopathol 2013; 35:351-73. [PMID: 23572207 PMCID: PMC3641308 DOI: 10.1007/s00281-013-0370-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 03/13/2013] [Indexed: 12/16/2022]
Abstract
Increased endoplasmic reticulum (ER) stress and the activated unfolded protein response (UPR) signaling associated with it play key roles in physiological processes as well as under pathological conditions. The UPR normally protects cells and re-establishes cellular homeostasis, but prolonged UPR activation can lead to the development of various pathologies. These features make the UPR signaling pathway an attractive target for the treatment of diseases whose pathogenesis is characterized by chronic activation of this pathway. Here, we focus on the molecular signaling pathways of the UPR and suggest possible ways to target this response for therapeutic purposes.
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18
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The role of the unfolded protein response in diabetes mellitus. Semin Immunopathol 2013; 35:333-50. [PMID: 23529219 DOI: 10.1007/s00281-013-0369-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 03/13/2013] [Indexed: 12/13/2022]
Abstract
The endoplasmic reticulum (ER) plays a key role in the synthesis and modification of secretory and membrane proteins in all eukaryotic cells. Under normal conditions, these proteins are correctly folded and assembled in the ER. However, when cells are exposed to environmental factors such as overproduction of ER proteins, viral infections, or glucose deprivation, the secretory and membrane proteins can accumulate in unfolded or misfolded forms in the lumen of the ER, and consequently, cause stress in the ER. To maintain cellular homeostasis, cells induce several responses to ER stress. In mammalian cells, ER stress responses are induced by a diversity of signal pathways. There are three ER-located transmembrane proteins that play important roles in mammalian ER stress responses: activating transcription factor 6, inositol-requiring protein 1, and protein kinase RNA-like endoplasmic reticulum kinase. ER stress is linked to various diseases, including diabetes. This review highlights the particular importance of ER stress-responsive molecules in insulin biosynthesis, glyconeogenesis, insulin resistance, glucose intolerance, and pancreatic β-cell apoptosis. An understanding of the pathogenic mechanism of diabetes from the aspect of ER stress is crucial in formulating therapeutic strategies.
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19
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Zhang Y, Zhang M, Wu J, Lei G, Li H. Transcriptional Regulation of the Ufm1 Conjugation System in Response to Disturbance of the Endoplasmic Reticulum Homeostasis and Inhibition of Vesicle Trafficking. PLoS One 2012; 7:e48587. [PMID: 23152784 PMCID: PMC3496721 DOI: 10.1371/journal.pone.0048587] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/03/2012] [Indexed: 01/22/2023] Open
Abstract
Homeostasis of the endoplasmic reticulum (ER) is essential for normal cellular functions. Disturbance of this homeostasis causes ER stress and activates the Unfolded Protein Response (UPR). The Ufm1 conjugation system is a novel Ubiquitin-like (Ubl) system whose physiological target(s) and biological functions remain largely undefined. Genetic study has demonstrated that the Ufm1-activating enzyme Uba5 is indispensible for erythroid differentiation in mice, highlighting the importance of this novel system in animal development. In this report we present the evidence for involvement of RCAD/Ufl1, a putative Ufm1-specific E3 ligase, and its binding partner C53/LZAP protein in ufmylation of endogenous Ufm1 targets. Moreover, we found that the Ufm1 system was transcriptionally up-regulated by disturbance of the ER homeostasis and inhibition of vesicle trafficking. Using luciferase reporter and ChIP assays, we dissected the Ufm1 promoter and found that Ufm1 was a potential target of Xbp-1, one of crucial transcription factors in UPR. We further examined the effect of Xbp-1 deficiency on the expression of the Ufm1 components. Interestingly, the expression of Ufm1, Uba5, RCAD/Ufl1 and C53/LZAP in wild-type mouse embryonic fibroblasts (MEFs) was significantly induced by inhibition of vesicle trafficking, but the induction was negated by Xbp-1 deficiency. Finally, we found that knockdown of the Ufm1 system in U2OS cells triggered UPR and amplification of the ER network. Taken together, our study provided critical insight into the regulatory mechanism of the Ufm1 system and established a direct link between this novel Ubl system and the ER network.
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Affiliation(s)
- Yinghua Zhang
- Department of Biochemistry and Molecular Biology, Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Mingsheng Zhang
- Department of Biochemistry and Molecular Biology, Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jianchun Wu
- Cancer Center, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Guohua Lei
- Department of Biophysics, Southern Medical University, Guangzhou, Guangdong, China
| | - Honglin Li
- Department of Biochemistry and Molecular Biology, Cancer Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
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20
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Inhibition of endoplasmic reticulum stress improves mouse embryo development. PLoS One 2012; 7:e40433. [PMID: 22808162 PMCID: PMC3396646 DOI: 10.1371/journal.pone.0040433] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 06/06/2012] [Indexed: 01/08/2023] Open
Abstract
X-box binding protein-1 (XBP-1) is an important regulator of a subset of genes during endoplasmic reticulum (ER) stress. In the current study, we analyzed endogenous XBP-1 expression and localization, with a view to determining the effects of ER stress on the developmental competency of preimplantation embryos in mice. Fluorescence staining revealed that functional XBP-1 is localized on mature oocyte spindles and abundant in the nucleus at the germinal vesicle (GV) stage. However, in preimplantation embryos, XBP-1 was solely detected in the cytoplasm at the one-cell stage. The density of XBP-1 was higher in the nucleus than the cytoplasm at the two-cell, four-cell, eight-cell, morula, and blastocyst stages. Furthermore, RT-PCR analysis confirmed active XBP-1 mRNA splicing at all preimplantation embryo stages, except the one-cell stage. Tunicamycin (TM), an ER stress inducer used as a positive control, promoted an increase in the density of nuclear XBP-1 at the one-cell and two-cell stages. Similarly, culture medium supplemented with 25 mM sorbitol displayed a remarkable increase active XBP-1 expression in the nuclei of 1-cell and 2-cell embryos. Conversely, high concentrations of TM or sorbitol led to reduced nuclear XBP-1 density and significant ER stress-induced apoptosis. Tauroursodeoxycholic acid (TUDCA), a known inhibitor of ER stress, improved the rate of two-cell embryo development to blastocysts by attenuating the expression of active XBP-1 protein in the nucleus at the two-cell stage. Our data collectively suggest that endogenous XBP-1 plays a role in normal preimplantation embryonic development. Moreover, XBP-1 splicing is activated to generate a functional form in mouse preimplantation embryos during culture stress. TUDCA inhibits hyperosmolar-induced ER stress as well as ER stress-induced apoptosis during mouse preimplantation embryo development.
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21
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The Myocardial Unfolded Protein Response during Ischemic Cardiovascular Disease. Biochem Res Int 2012; 2012:583170. [PMID: 22536506 PMCID: PMC3321442 DOI: 10.1155/2012/583170] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 01/10/2012] [Indexed: 01/01/2023] Open
Abstract
Heart failure is a progressive and disabling disease. The incidence of heart failure is also on the rise, particularly in the elderly of industrialized societies. This is in part due to an increased ageing population, whom initially benefits from improved, and life-extending cardiovascular therapy, yet ultimately succumb to myocardial failure. A major cause of heart failure is ischemia secondary to the sequence of events that is dyslipidemia, atherosclerosis, and myocardial infarction. In the case of heart failure postmyocardial infarction, ischemia can lead to myocardial cell death by both necrosis and apoptosis. The extent of myocyte death postinfarction is associated with adverse cardiac remodeling that can contribute to progressive heart chamber dilation, ventricular wall thinning, and the onset of loss of cardiac function. In cardiomyocytes, recent studies indicate that myocardial ischemic injury activates the unfolded protein stress response (UPR) and this is associated with increased apoptosis. This paper focuses on the intersection of ischemia, the UPR, and cell death in cardiomyocytes. Targeting of the myocardial UPR may prove to be a viable target for the prevention of myocyte cell loss and the progression of heart failure due to ischemic injury.
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22
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Jiang Z, Fan Q, Zhang Z, Zou Y, Cai R, Wang Q, Zuo Y, Cheng J. SENP1 deficiency promotes ER stress-induced apoptosis by increasing XBP1 SUMOylation. Cell Cycle 2012; 11:1118-22. [PMID: 22370484 DOI: 10.4161/cc.11.6.19529] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The transcription factor X box-binding protein 1 (XBP1) is a key component of the endoplasmic reticulum (ER) stress response. Recently, it has been reported that the spliced XBP1 (XBP1s), an activated XBP1 during ER stress, can be SUMOylated. Here, we identify Sentrin/SUMO-specific protease 1 (SENP1) as a specific de-SUMOylation protease for XBP1. SENP1 can increase the transcriptional activity of XBP1. In Senp1 (-/-) cells, the SUMOylated XBP1 is accumulated, and the expression of XBP1 target genes is downregulated in response to ER stress. Moreover, SENP1 deficiency significantly increases ER stress-induced apoptosis through accumulating XBP1 SUMOylation. These results reveal an essential function of SENP1 in ER stress response through regulating XBP1 SUMOylation.
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Affiliation(s)
- Zhou Jiang
- Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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23
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Endoplasmic reticulum stress and diabetic cardiomyopathy. EXPERIMENTAL DIABETES RESEARCH 2011; 2012:827971. [PMID: 22144992 PMCID: PMC3226330 DOI: 10.1155/2012/827971] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 01/02/2023]
Abstract
The endoplasmic reticulum (ER) is an organelle entrusted with lipid synthesis, calcium homeostasis, protein folding, and maturation. Perturbation of ER-associated functions results in an evolutionarily conserved cell stress response, the unfolded protein response (UPR) that is also called ER stress. ER stress is aimed initially at compensating for damage but can eventually trigger cell death if ER stress is excessive or prolonged. Now the ER stress has been associated with numerous diseases. For instance, our recent studies have demonstrated the important role of ER stress in diabetes-induced cardiac cell death. It is known that apoptosis has been considered to play a critical role in diabetic cardiomyopathy. Therefore, this paper will summarize the information from the literature and our own studies to focus on the pathological role of ER stress in the development of diabetic cardiomyopathy. Improved understanding of the molecular mechanisms underlying UPR activation and ER-initiated apoptosis in diabetic cardiomyopathy will provide us with new targets for drug discovery and therapeutic intervention.
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24
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Zhang JY, Lee KS, Kim JS, Song BS, Jin DI, Koo DB, Yu K. Functional characterization of the ER stress induced X-box-binding protein-1 (Xbp-1) in the porcine system. BMC Mol Biol 2011; 12:25. [PMID: 21605464 PMCID: PMC3112107 DOI: 10.1186/1471-2199-12-25] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 05/24/2011] [Indexed: 12/05/2022] Open
Abstract
Background The unfolded protein response (UPR) is an evolutionary conserved adaptive reaction for increasing cell survival under endoplasmic reticulum (ER) stress conditions. X-box-binding protein-1 (Xbp1) is a key transcription factor of UPR that activates genes involved in protein folding, secretion, and degradation to restore ER function. The UPR induced by ER stress was extensively studied in diseases linked to protein misfolding and aggregations. However, in the porcine system, genes in the UPR pathway were not investigated. In this study, we isolated and characterized the porcine Xbp1 (pXbp1) gene in ER stress using porcine embryonic fibroblast (PEF) cells and porcine organs. ER stress was induced by the treatment of tunicamycin and cell viability was investigated by the MTT assay. For cloning and analyzing the expression pattern of pXbp1, RT-PCR analysis and Western blot were used. Knock-down of pXbp1 was performed by the siRNA-mediated gene silencing. Results We found that the pXbp1 mRNA was the subject of the IRE1α-mediated unconventional splicing by ER stress. Knock-down of pXbp1 enhanced ER stress-mediated cell death in PEF cells. In adult organs, pXbp1 mRNA and protein were expressed and the spliced forms were detected. Conclusions It was first found that the UPR mechanisms and the function of pXbp1 in the porcine system. These results indicate that pXbp1 plays an important role during the ER stress response like other animal systems and open a new opportunity for examining the UPR pathway in the porcine model system.
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Affiliation(s)
- Jin-Yu Zhang
- Aging Research Centre, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
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25
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Uncovering the transcriptional circuitry in skeletal muscle regeneration. Mamm Genome 2011; 22:272-81. [PMID: 21509518 DOI: 10.1007/s00335-011-9322-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 03/07/2011] [Indexed: 02/04/2023]
Abstract
Skeletal muscle has a remarkable ability to regenerate after repeated and complete destruction of the tissue. The healing phases for an injured muscle undergo an activation program controlled by a dynamically inducible transcriptional regulatory network. Mapping a complex mammalian transcriptional network is confronted by significant challenges and requires the integration of multiple experimental data types. In this work we present a system approach to describe the transcriptional circuitry during skeletal muscle regeneration using time-course expression data and motif scanning information. Time-lagged correlation analysis was utilized to evaluate the transcription factor (TF) → target associations. Our analysis identified six TFs that potentially play a central role throughout the regeneration process. Four of them have previously been described to be important for muscle regeneration and differentiation. The remaining two TFs are identified as novel regulators that may have a role in the regeneration process. We hope that our work may provide useful clues to help accelerate the recovery process in injured skeletal muscle.
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26
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Abstract
Unfolded protein response (UPR) is a key cellular defense mechanism associated with many human "conformational" diseases, including heart diseases, neurodegeneration, and metabolic syndrome. One of the major obstacles that have hindered our further understanding of physiological UPR and its future therapeutic potential is our inability to detect and quantitate ER stress and UPR activation under physiological and pathological conditions, where ER stress is perceivably very mild. Here, we describe a Phos-tag-based Western blot approach that allows for direct visualization and quantitative assessment of mild ER stress and UPR signaling, directly at the levels of UPR sensors, in various in vivo conditions. This method will likely pave the foundation for future studies on physiological UPR, aid in the diagnosis of ER-associated diseases, and facilitate therapeutic strategies targeting UPR in vivo.
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Affiliation(s)
- Ling Qi
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
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27
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Yang L, Xue Z, He Y, Sun S, Chen H, Qi L. A Phos-tag-based approach reveals the extent of physiological endoplasmic reticulum stress. PLoS One 2010; 5:e11621. [PMID: 20661282 PMCID: PMC2905412 DOI: 10.1371/journal.pone.0011621] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Accepted: 06/21/2010] [Indexed: 11/18/2022] Open
Abstract
Cellular response to endoplasmic reticulum (ER) stress or unfolded protein response (UPR) is a key defense mechanism associated with many human diseases. Despite its basic and clinical importance, the extent of ER stress inflicted by physiological and pathophysiological conditions remains difficult to quantitate, posing a huge obstacle that has hindered our further understanding of physiological UPR and its future therapeutic potential. Here we have optimized a Phos-tag-based system to detect the activation status of two proximal UPR sensors at the ER membrane. This method allowed for a quantitative assessment of the level of stress in the ER. Our data revealed quantitatively the extent of tissue-specific basal ER stress as well as ER stress caused by the accumulation of misfolded proteins and the fasting-refeeding cycle. Our study may pave the foundation for future studies on physiological UPR, aid in the diagnosis of ER-associated diseases and improve and facilitate therapeutic strategies targeting UPR in vivo.
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Affiliation(s)
- Liu Yang
- Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York, United States of America
| | - Zhen Xue
- Graduate Program in Nutrition, Cornell University, Ithaca, New York, United States of America
| | - Yin He
- Graduate Program in Genetics and Development, Cornell University, Ithaca, New York, United States of America
| | - Shengyi Sun
- Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York, United States of America
| | - Hui Chen
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
| | - Ling Qi
- Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York, United States of America
- Graduate Program in Nutrition, Cornell University, Ithaca, New York, United States of America
- Graduate Program in Genetics and Development, Cornell University, Ithaca, New York, United States of America
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Abstract
The UPR (unfolded protein response), a cellular defence mechanism against misfolded protein accumulation in the ER (endoplasmic reticulum), is associated with many human diseases such as aging, cancer and diabetes. XBP1 (X-box-binding protein 1), a key transcription factor of the UPR, is critical in maintaining ER homoeostasis. Nevertheless, the mechanism by which XBP1 transcriptional activity is regulated remains unexplored. In the present study we show that XBP1s, the active spliced form of XBP1 protein, is SUMOylated, mainly by PIAS2 [protein inhibitor of activated STAT (signal transducer and activator of transcription) 2] at two lysine residues located in the C-terminal transactivation domain. Ablation of these SUMOylation events significantly enhances the transcriptional activity of XBP1s towards UPR target genes. Thus our results reveal an unexpected role for SUMO (small ubiquitin-related modifier) in the regulation of UPR activation and ER homeostasis.
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Abstract
X-box binding protein 1 (XBP1) is a unique basic region leucine zipper (bZIP) transcription factor whose active form is generated by a nonconventional splicing reaction upon disruption of homeostasis in the endoplasmic reticulum (ER) and activation of the unfolded protein response (UPR). XBP1, first identified as a key regulator of major histocompatibility complex (MHC) class II gene expression in B cells, represents the most conserved signaling component of UPR and is critical for cell fate determination in response to ER stress. Here we review recent advances in our understanding of this multifaceted transcription factor in health and diseases.
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Affiliation(s)
- Yin He
- *Graduate Program in Genetics and Development, Cornell University, Ithaca, NY, USA
| | - Shengyi Sun
- †Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY, USA
| | - Haibo Sha
- ‡Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Ziying Liu
- †Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY, USA
| | - Liu Yang
- †Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY, USA
| | - Zhen Xue
- §Graduate Program in Nutrition, Cornell University, Ithaca, NY, USA
| | - Hui Chen
- ‡Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Ling Qi
- *Graduate Program in Genetics and Development, Cornell University, Ithaca, NY, USA
- †Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY, USA
- ‡Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
- §Graduate Program in Nutrition, Cornell University, Ithaca, NY, USA
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Sha H, He Y, Chen H, Wang C, Zenno A, Shi H, Yang X, Zhang X, Qi L. The IRE1alpha-XBP1 pathway of the unfolded protein response is required for adipogenesis. Cell Metab 2009; 9:556-64. [PMID: 19490910 PMCID: PMC2963107 DOI: 10.1016/j.cmet.2009.04.009] [Citation(s) in RCA: 210] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 04/02/2009] [Accepted: 04/28/2009] [Indexed: 11/29/2022]
Abstract
Signaling cascades during adipogenesis culminate in the expression of two essential adipogenic factors, PPARgamma and C/EBPalpha. Here we demonstrate that the IRE1alpha-XBP1 pathway, the most conserved branch of the unfolded protein response (UPR), is indispensable for adipogenesis. Indeed, XBP1-deficient mouse embryonic fibroblasts and 3T3-L1 cells with XBP1 or IRE1alpha knockdown exhibit profound defects in adipogenesis. Intriguingly, C/EBPbeta, a key early adipogenic factor, induces Xbp1 expression by directly binding to its proximal promoter region. Subsequently, XBP1 binds to the promoter of Cebpa and activates its gene expression. The posttranscriptional splicing of Xbp1 mRNA by IRE1alpha is required as only the spliced form of XBP1 (XBP1s) rescues the adipogenic defect exhibited by XBP1-deficient cells. Taken together, our data show that the IRE1alpha-XBP1 pathway plays a key role in adipocyte differentiation by acting as a critical regulator of the morphological and functional transformations during adipogenesis.
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Affiliation(s)
- Haibo Sha
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
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31
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Abstract
Over the last decade, it has become clear that the accumulation of misfolded proteins contributes to a number of neurodegenerative, immune, and endocrine pathologies, as well as other age-related illnesses. Recent interest has focused on the possibility that the accumulation of misfolded proteins can also contribute to vascular and cardiac diseases. In large part, the misfolding of proteins takes place during synthesis on free ribosomes in the cytoplasm or on endoplasmic reticulum ribosomes. In fact, even under optimal conditions, approximately 30% of all newly synthesized proteins are rapidly degraded, most likely because of improper folding. Accordingly, stresses that perturb the folding of proteins during or soon after synthesis can lead to the accumulation of misfolded proteins and to potential cellular dysfunction and pathological consequences. To avert such outcomes, cells have developed elaborate protein quality-control systems for detecting misfolded proteins and making appropriate adjustments to the machinery responsible for protein synthesis and/or degradation. Important contributors to protein quality control include cytosolic and organelle-targeted molecular chaperones, which help fold and stabilize proteins from unfolding, and the ubiquitin proteasome system, which degrades terminally misfolded proteins. Both of these systems play important roles in cardiovascular biology. The focus of this review is the endoplasmic reticulum stress response, a protein quality-control and signal-transduction system that has not been well studied in the context of cardiovascular biology but that could be important for vascular and cardiac health and disease.
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Affiliation(s)
- Christopher C Glembotski
- SDSU Heart Institute and the Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182, USA.
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Glembotski CC. The role of the unfolded protein response in the heart. J Mol Cell Cardiol 2007; 44:453-9. [PMID: 18054039 DOI: 10.1016/j.yjmcc.2007.10.017] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 10/14/2007] [Accepted: 10/18/2007] [Indexed: 12/14/2022]
Abstract
The misfolding of nascent proteins, or the unfolding of proteins after synthesis is complete, can occur in response to numerous environmental stresses, or as a result of mutations that de-stabilize protein structure. Cells have developed elaborate protein quality control systems that recognize improperly folded proteins and either refold them or facilitate their degradation. One such quality control system is the unfolded protein response, or the UPR. The UPR is a highly conserved signal transduction system that is activated when cells are subjected to conditions that alter the endoplasmic reticulum (ER) in ways that impair the folding of nascent proteins in this organelle. Recent observations indicate that in the heart, the UPR is activated during acute stresses, including ischemia/reperfusion, as well as upon longer term stresses that lead to cardiac hypertrophy and heart failure. Moreover, certain aspects of the UPR are activated during, and are required for proper heart development. This review summarizes recent studies of the UPR in the heart, focusing on the possible roles of the UPR in contributing to, or protecting from ischemia/reperfusion damage.
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Affiliation(s)
- Christopher C Glembotski
- The SDSU Heart Institute and The Department of Biology, San Diego State University, San Diego, CA 92182, USA
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Abstract
Cytoplasmic splicing is one of the major regulatory mechanisms of the unfolded protein response (UPR). The molecular mechanism of cytoplasmic splicing is unique and completely different from that of conventional nuclear splicing. The mammalian substrate of cytoplasmic splicing is XBP1 pre-mRNA, which is converted to spliced mRNA in response to UPR, leading to the production of an active transcription factor [pXBP1(S)] responsible for UPR. Interestingly, XBP1 pre-mRNA is also translated into a functional protein [pXBP1(U)] that negatively regulates the UPR. Thus, mammalian cells can quickly adapt to a change in conditions in the endoplasmic reticulum by switching proteins encoded in the mRNA from a negative regulator to an activator. This elaborate system contributes to various cellular functions, including plasma cell differentiation, viral infections, and carcinogenesis. In this short review, I briefly summarize research on cytoplasmic splicing and focus on current hot topics.
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Affiliation(s)
- Hiderou Yoshida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan., PRESTO-SORST, Japan Science and Technology Agency, Kyoto, Japan.
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Acosta-Alvear D, Zhou Y, Blais A, Tsikitis M, Lents NH, Arias C, Lennon CJ, Kluger Y, Dynlacht BD. XBP1 controls diverse cell type- and condition-specific transcriptional regulatory networks. Mol Cell 2007; 27:53-66. [PMID: 17612490 DOI: 10.1016/j.molcel.2007.06.011] [Citation(s) in RCA: 622] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 06/04/2007] [Accepted: 06/13/2007] [Indexed: 01/18/2023]
Abstract
Using genome-wide approaches, we have elucidated the regulatory circuitry governed by the XBP1 transcription factor, a key effector of the mammalian unfolded protein response (UPR), in skeletal muscle and secretory cells. We identified a core group of genes involved in constitutive maintenance of ER function in all cell types and tissue- and condition-specific targets. In addition, we identified a cadre of unexpected targets that link XBP1 to neurodegenerative and myodegenerative diseases, as well as to DNA damage and repair pathways. Remarkably, we found that XBP1 regulates functionally distinct targets through different sequence motifs. Further, we identified Mist1, a critical regulator of differentiation, as an important target of XBP1, providing an explanation for developmental defects associated with XBP1 loss of function. Our results provide a detailed picture of the regulatory roadmap governed by XBP1 in distinct cell types as well as insight into unexplored functions of XBP1.
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Souid S, Lepesant JA, Yanicostas C. The xbp-1 gene is essential for development in Drosophila. Dev Genes Evol 2007; 217:159-67. [PMID: 17206451 DOI: 10.1007/s00427-006-0124-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 11/15/2006] [Indexed: 12/22/2022]
Abstract
We report in this paper the characterization of Dxbp-1, the Drosophila homologue of the xpb-1 gene that encodes a "bZIP"-containing transcription factor that plays a key role in the unfolded protein response (UPR), an evolutionarily conserved signalling pathway activated by an overload of misfolded proteins in the endoplasmic reticulum (ER). Dxbp-1 is ubiquitously transcribed, and high levels are found in embryonic salivary glands and in the ovarian follicle cells committed to the synthesis of the respiratory appendages. Loss of function of Dxbp-1 induced a recessive larval lethality, thus, revealing an essential requirement for this gene. The Dxbp-1 transcript was submitted to an "unconventional" splicing that generated a processed Dxbp-1s transcript encoding a DXbp-1 protein isoform, as is the case for yeast, Caenorhabditis elegans and vertebrate hac1/xbp-1 transcripts after UPR activation. However, in the absence of exogenously induced ER stress, the Dxbp-1s transcript was also detectable not only throughout embryonic and larval development but also in adults with a high level of accumulation in the male sexual apparatus and, to a lesser extent, in the salivary glands of the third-instar larvae. Using a Dxbp-1:GFP transgene as an in vivo reporter for Dxbp-1 mRNA unconventional splicing, we confirmed that Dxbp-1 processing took place in the salivary glands of the third-instar larvae. The Dxbp-1 gene appears, thus, to play an essential role during the development of Drosophila, hypothetically by stimulating the folding capacities of the ER in cells committed to intense secretory activities.
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Affiliation(s)
- Sami Souid
- Institut Jacques Monod, UMR 7592, CNRS, Université Denis-Diderot Paris 7 and Université Paris 6 Pierre et Marie Curie, 2, Place Jussieu, 75251, Paris Cedex 05, France
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Thuerauf DJ, Marcinko M, Gude N, Rubio M, Sussman MA, Glembotski CC. Activation of the unfolded protein response in infarcted mouse heart and hypoxic cultured cardiac myocytes. Circ Res 2006; 99:275-82. [PMID: 16794188 DOI: 10.1161/01.res.0000233317.70421.03] [Citation(s) in RCA: 239] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Endoplasmic reticulum (ER) stresses that reduce ER protein folding activate the unfolded protein response (UPR). One effector of the UPR is the transcription factor X-box binding protein-1 (XBP1), which is expressed on ER stress-mediated splicing of the XBP1 mRNA. XBP1 induces certain ER-targeted proteins, eg, glucose-regulated protein 78 (GRP78), that help resolve the ER stress and foster cell survival. In this study, we determined whether hypoxia can activate the UPR in the cardiac context. Neonatal rat ventricular myocyte cultures subjected to hypoxia (16 hours) exhibited increased XBP1 mRNA splicing, XBP1 protein expression, GRP78 promoter activation, and GRP78 protein levels; however, the levels of these UPR markers declined during reoxygenation, suggesting that the UPR is activated during hypoxia but not during reoxygenation. When cells were infected with a recombinant adenovirus (AdV) encoding dominant-negative XBP1 (AdV-XBP1dn), UPR markers were reduced; however, hypoxia/reoxygenation-induced apoptosis increased. Confocal immunocytofluorescence demonstrated that hypoxia induced GRP78 in neonatal rat and isolated adult mouse ventricular myocytes. Moreover, mouse hearts subjected to in vivo myocardial infarction exhibited increased GRP78 expression in cardiac myocytes near the infarct, but not in healthy cells distal to the infarct. These results indicate that hypoxia activates the UPR in cardiac myocytes and that XBP1-inducible proteins may contribute to protecting the myocardium during hypoxic stress.
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Affiliation(s)
- Donna J Thuerauf
- San Diego State University Heart Institute and the Department of Biology, San Diego State University, Calif. 92182, USA
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39
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Shen X, Zhang K, Kaufman RJ. The unfolded protein response--a stress signaling pathway of the endoplasmic reticulum. J Chem Neuroanat 2004; 28:79-92. [PMID: 15363493 DOI: 10.1016/j.jchemneu.2004.02.006] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Accepted: 02/15/2004] [Indexed: 12/20/2022]
Abstract
The endoplasmic reticulum (ER) is a factory for folding and maturation of newly synthesized transmembrane and secretory proteins. The ER provides stringent quality control systems to ensure that only correctly folded proteins exit the ER and unfolded or misfolded proteins are retained and ultimately degraded. A number of biochemical and physiological stimuli can change ER homeostasis, impose stress to the ER, and subsequently lead to accumulation of unfolded or misfolded proteins in the ER lumen. The ER has evolved stress response signaling pathways collectively called the unfolded protein response (UPR) to cope with the accumulation of unfolded or misfolded proteins. This review summarizes our understanding of the UPR signaling developed in the recent years.
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Affiliation(s)
- Xiaohua Shen
- Howard Hughes Medical Institute, The University of Michigan Medical Center, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA
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40
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Kadowaki H, Nishitoh H, Ichijo H. Survival and apoptosis signals in ER stress: the role of protein kinases. J Chem Neuroanat 2004; 28:93-100. [PMID: 15363494 DOI: 10.1016/j.jchemneu.2004.05.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Accepted: 05/10/2004] [Indexed: 12/28/2022]
Abstract
The endoplasmic reticulum (ER) is the organelle in which newly synthesized secretory and transmembrane proteins form their proper tertiary structure by post-translational modification, folding, and oligomerization. However, many of these proteins are unfolded or misfolded by extracellular or intracellular stimuli. The accumulation of misfolded proteins constitutes a risk for living cells. Eukaryotic cells possess at least three different mechanisms to adapt to ER stress and thereby survive: (1) translational attenuation to limit further accumulation of misfolded proteins; (2) transcriptional activation of genes encoding ER-resident chaperones; and (3) the ER-associated degradation (ERAD) pathway to restore the folding capacity. If the cells are exposed to prolonged or strong ER stress, the cells are destroyed by apoptosis. Recent evidence indicates that ER stress signaling pathways are mediated in part by several protein kinases and play an important role in the pathogenesis of neurodegenerative disorders. The main purpose of this review is to summarize current knowledge about the protein kinases involved in ER stress, and their involvement in the pathogenesis of neurodegenerative disorders.
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Affiliation(s)
- Hisae Kadowaki
- Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo,7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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41
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Hamada H, Suzuki M, Yuasa S, Mimura N, Shinozuka N, Takada Y, Suzuki M, Nishino T, Nakaya H, Koseki H, Aoe T. Dilated cardiomyopathy caused by aberrant endoplasmic reticulum quality control in mutant KDEL receptor transgenic mice. Mol Cell Biol 2004; 24:8007-17. [PMID: 15340063 PMCID: PMC515036 DOI: 10.1128/mcb.24.18.8007-8017.2004] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Aberrant protein folding beyond the capacity of endoplasmic reticulum (ER) quality control leads to stress response in the ER. The Lys-Asp-Glu-Leu (KDEL) receptor, a retrieval receptor for ER chaperones in the early secretory pathway, contributes to ER quality control. To elucidate the function of the KDEL receptor in vivo, we established transgenic mice expressing a mutant KDEL receptor. We found that the mutant KDEL receptor sensitized cells to ER stress and that the mutant mice developed dilated cardiomyopathy. Ultrastructural analyses revealed expanded sarcoplasmic reticulums and protein aggregates that obstructed the adjacent transverse tubules of the mutant cardiomyocytes. Cardiomyocytes from the mutant mice were sensitive to ER stress when treated with tunicamycin and showed a functional defect in the L-type Ca(2+) current. We observed ubiquitinated protein aggregates, enhanced expression of CHOP (a death-related transcriptional factor expressed upon ER stress), and apoptosis in the mutant hearts. These findings suggest that impairment of the KDEL receptor disturbs ER quality control, resulting in accumulation of misfolded proteins in the ER in an in vivo system, and that the dilated cardiomyopathy found in the mutant KDEL receptor transgenic mice is associated with ER stress.
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MESH Headings
- Animals
- Calcium Signaling
- Cardiomyopathy, Dilated/etiology
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/pathology
- Endoplasmic Reticulum/metabolism
- Golgi Apparatus/metabolism
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mice, Transgenic
- Models, Cardiovascular
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/ultrastructure
- Protein Folding
- Rats
- Rats, Sprague-Dawley
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sarcoplasmic Reticulum/metabolism
- Sarcoplasmic Reticulum/ultrastructure
- Stress, Mechanical
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Affiliation(s)
- Hiromichi Hamada
- Department of Molecular Embryology, Chiba University Graduate School of Medicine, Chuo-ku, Chiba City, Chiba, Japan
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Nozaki JI, Kubota H, Yoshida H, Naitoh M, Goji J, Yoshinaga T, Mori K, Koizumi A, Nagata K. The endoplasmic reticulum stress response is stimulated through the continuous activation of transcription factors ATF6 and XBP1 in Ins2+/Akita pancreatic beta cells. Genes Cells 2004; 9:261-70. [PMID: 15005713 DOI: 10.1111/j.1356-9597.2004.00721.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The dominant C96Y mutation of one of the two murine insulin genes, Ins2, causes diabetes mellitus in 'Akita' mice. Here we established pancreatic islet beta cell lines from heterozygous mice (Ins2+/Akita). Western blot analysis of endoplasmic reticulum (ER) molecular chaperones indicated that Grp78, Grp94 and Orp150 are significantly increased in Ins2+/Akita cells compared with wild-type (Ins2+/+) cells. Reporter gene assays using the human GRP78 promoter with or without the ER stress response element (ERSE) showed that Ins2+/Akita cells exhibit significantly stronger ERSE-dependent transcriptional activity than Ins2+/+ cells. Transient over-expression of the Ins2 C96Y mutant in wild-type beta cells induces a stronger ERSE-dependent stress response than does wild-type Ins2 over-expression. The ERSE-binding transcription factor ATF6 is strongly activated in Ins2+/Akita cells. The activity of a reporter containing the specific binding sequence of another ERSE-binding transcription factor, XBP1, is also enhanced in Ins2+/Akita cells. Levels of active forms of XBP1 mRNA and protein are both markedly elevated in Ins2+/Akita cells. These results indicate that this cell line is subject to continuous ER stress and that the Ins2 C96Y mutation induces the expression of ER chaperones through the activation of ATF6 and XBP1.
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Affiliation(s)
- Jun ichi Nozaki
- Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8397, Japan
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Fujimoto T, Onda M, Nagai H, Nagahata T, Ogawa K, Emi M. Upregulation and overexpression of human X-box binding protein 1 (hXBP-1) gene in primary breast cancers. Breast Cancer 2004; 10:301-6. [PMID: 14634507 DOI: 10.1007/bf02967649] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Human X-box binding protein 1 (hXBP-1) is a transcription factor essential for hepatocyte growth as well as for plasma cell differentiation. hXBP-1 also binds to cis-elements of human T cell leukemia virus and human major histocompatibility complex genes. In order to clarify the role of XBP-1 in breast cancer, here we investigated the expression of XBP-1 in 11 primary breast cancers and 5 breast cancer cell lines. MATERIALS AND METHODS The study population consisted of eleven patients who were underwent surgery for breast cancer from 2000 to 2002. Five breast cancer cell lines (MDA-MB-453, CRL1500, YMB-1-E, MCF7 and HBL100) were analyzed for XBP-1 expression. Reverse transcription polymerase chain reaction was performed on 6 primary breast cancers. Then we investigated XBP-1 expression by immunohistochemically on archived paraffin-embedded sections. RESULTS hXBP-1 mRNA expression was increased in all 11 primary breast cancers we examined, as well as 5 breast cancer cell lines, but hardly detectable in non-cancerous breast tissue. Immunohistochemical staining demonstrated that hXBP-1 protein stained strongly in the cytoplasm of cancer cells but was unreactive in the normal breast ductal epithelial and myoepithelial cells. CONCLUSIONS These data indicate that increased expression of the hXBP-1 gene may play some role in human breast carcinogenesis through impairment of cell differentiation regulation.
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Affiliation(s)
- Takashi Fujimoto
- Department of Molecular Biology, Institute of Gerontology, Nippon Medical School, 1-396, Kosugi-cho, Nakahara-ku, Kawasaki 211-8533, Japan
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45
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Harding HP, Calfon M, Urano F, Novoa I, Ron D. Transcriptional and translational control in the Mammalian unfolded protein response. Annu Rev Cell Dev Biol 2003; 18:575-99. [PMID: 12142265 DOI: 10.1146/annurev.cellbio.18.011402.160624] [Citation(s) in RCA: 731] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells monitor the physiological load placed on their endoplasmic reticulum (ER) and respond to perturbations in ER function by a process known as the unfolded protein response (UPR). In metazoans the UPR has a transcriptional component that up-regulates expression of genes that enhance the capacity of the organelle to deal with the load of client proteins and a translational component that insures tight coupling between protein biosynthesis on the cytoplasmic side and folding in the ER lumen. Together, these two components adapt the secretory apparatus to physiological load and protect cells from the consequences of protein malfolding.
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Affiliation(s)
- Heather P Harding
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York 10016, USA.
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46
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Affiliation(s)
- Randal J Kaufman
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor 48109-0650, USA.
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47
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Affiliation(s)
- Randal J Kaufman
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor 48109-0650, USA.
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48
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Takahashi S, Suzuki S, Inaguma S, Ikeda Y, Cho YM, Nishiyama N, Fujita T, Inoue T, Hioki T, Sugimura Y, Ushijima T, Shirai T. Down-regulation of human X-box binding protein 1 (hXBP-1) expression correlates with tumor progression in human prostate cancers. Prostate 2002; 50:154-61. [PMID: 11813207 DOI: 10.1002/pros.10044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND In our previous study, the gene encoding the human X-box binding protein 1 (hXBP-1) was isolated as a down-regulated gene in advanced prostate cancers using cDNA-representational difference analysis (RDA). In the present investigation, we characterized alterations of hXBP-1 in prostate cancer specimens. METHODS Expression patterns of hXBP-1 in a series of human prostate cancers were examined by Northern blotting, mRNA in situ hybridization or immunohistochemistry. Loss of heterozygosity (LOH) analysis using microsatellite markers and gene mutation analysis in the hXBP-1 region were also performed. RESULTS Expression of hXBP-1 was localized in epithelial and adenocarcinoma cells of the prostate. An inverse correlation between hXBP-1 expression and histological differentiation was found in a series of prostate cancers without hormonal therapy. Majority of refractory cancer cases exhibited weak hXBP-1 expression. No allelic loss or gene mutations were found in the hXBP-1 region and its open reading frame, respectively, in the prostate cancer examined. CONCLUSIONS These results suggest that reduction of hXBP-1 expression may be a useful marker for prostate adenocarcinoma differentiation and progression.
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Affiliation(s)
- Satoru Takahashi
- First Department of Pathology, Nagoya City University Medical School, Mizuho-Cho, Mizuho-Ku, Nagoya, Japan.
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Lee K, Tirasophon W, Shen X, Michalak M, Prywes R, Okada T, Yoshida H, Mori K, Kaufman RJ. IRE1-mediated unconventional mRNA splicing and S2P-mediated ATF6 cleavage merge to regulate XBP1 in signaling the unfolded protein response. Genes Dev 2002; 16:452-66. [PMID: 11850408 PMCID: PMC155339 DOI: 10.1101/gad.964702] [Citation(s) in RCA: 802] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
All eukaryotic cells respond to the accumulation of unfolded proteins in the endoplasmic reticulum (ER) by signaling an adaptive pathway termed the unfolded protein response (UPR). In yeast, a type-I ER transmembrane protein kinase, Ire1p, is the proximal sensor of unfolded proteins in the ER lumen that initiates an unconventional splicing reaction on HAC1 mRNA. Hac1p is a transcription factor required for induction of UPR genes. In higher eukaryotic cells, the UPR also induces site-2 protease (S2P)-mediated cleavage of ER-localized ATF6 to generate an N-terminal fragment that activates transcription of UPR genes. To elucidate the requirements for IRE1alpha and ATF6 for signaling the mammalian UPR, we identified a UPR reporter gene that was defective for induction in IRE1alpha-null mouse embryonic fibroblasts and S2P-deficient Chinese hamster ovary (CHO) cells. We show that the endoribonuclease activity of IRE1alpha is required to splice XBP1 (X-box binding protein) mRNA to generate a new C terminus, thereby converting it into a potent UPR transcriptional activator. IRE1alpha was not required for ATF6 cleavage, nuclear translocation, or transcriptional activation. However, ATF6 cleavage was required for IRE1alpha-dependent induction of UPR transcription. We propose that nuclear-localized IRE1alpha and cytoplasmic-localized ATF6 signaling pathways merge through regulation of XBP1 activity to induce downstream gene expression. Whereas ATF6 increases the amount of XBP1 mRNA, IRE1alpha removes an unconventional 26-nucleotide intron that increases XBP1 transactivation potential. Both processing of ATF6 and IRE1alpha-mediated splicing of XBP1 mRNA are required for full activation of the UPR.
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Affiliation(s)
- Kyungho Lee
- Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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Shen X, Ellis RE, Lee K, Liu CY, Yang K, Solomon A, Yoshida H, Morimoto R, Kurnit DM, Mori K, Kaufman RJ. Complementary signaling pathways regulate the unfolded protein response and are required for C. elegans development. Cell 2001; 107:893-903. [PMID: 11779465 DOI: 10.1016/s0092-8674(01)00612-2] [Citation(s) in RCA: 545] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The unfolded protein response (UPR) is a transcriptional and translational intracellular signaling pathway activated by the accumulation of unfolded proteins in the lumen of the endoplasmic reticulum (ER). We have used C. elegans as a genetic model system to dissect UPR signaling in a multicellular organism. C. elegans requires ire-1-mediated splicing of xbp-1 mRNA for UPR gene transcription and survival upon ER stress. In addition, ire-1/xbp-1 acts with pek-1, a protein kinase that mediates translation attenuation, in complementary pathways that are essential for worm development and survival. We propose that UPR transcriptional activation by ire-1 as well as translational attenuation by pek-1 maintain ER homeostasis. The results demonstrate that the UPR and ER homeostasis are essential for metazoan development.
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Affiliation(s)
- X Shen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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