451
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Abstract
Immune responses occur in the midst of a variety of cellular stresses that can severely perturb endoplasmic reticulum (ER) function. The unfolded protein response is a three-pronged signaling axis dedicated to preserving ER homeostasis. In this review, we highlight many important and emerging functional roles for ER stress in immunity, focusing on how the bidirectional cross talk between immunological processes and basic cell biology leads to pleiotropic signaling outcomes and enhanced sensitivity to inflammatory stimuli. We also discuss how dysregulated ER stress responses can provoke many diseases, including autoimmunity, firmly positioning the unfolded protein response as a major therapeutic target in human disease.
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Affiliation(s)
- Sarah E Bettigole
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065; ,
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452
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ERp29 deficiency affects sensitivity to apoptosis via impairment of the ATF6-CHOP pathway of stress response. Apoptosis 2014; 19:801-15. [PMID: 24370996 DOI: 10.1007/s10495-013-0961-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endoplasmic reticulum protein 29 (ERp29) belongs to the redox-inactive PDI-Dβ-subfamily of PDI-proteins. ERp29 is expressed in all mammalian tissues examined. Especially high levels of expression were observed in secretory tissues and in some tumors. However, the biological role of ERp29 remains unclear. In the present study we show, by using thyrocytes and primary dermal fibroblasts from adult ERp29(-/-) mice, that ERp29 deficiency affects the activation of the ATF6-CHOP-branch of unfolded protein response (UPR) without influencing the function of other UPR branches, like the ATF4-eIF2α-XBP1 signaling pathway. As a result of impaired ATF6 activation, dermal fibroblasts and adult thyrocytes from ERp29(-/-) mice display significantly lower apoptosis sensitivities when treated with tunicamycin and hydrogen peroxide. However, in contrast to previous reports, we could demonstrate that ERp29 deficiency does not alter thyroglobulin expression levels. Therefore, our study suggests that ERp29 acts as an escort factor for ATF6 and promotes its transport from ER to Golgi apparatus under ER stress conditions.
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453
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Glembotski CC. Finding the missing link between the unfolded protein response and O-GlcNAcylation in the heart. Circ Res 2014; 115:546-8. [PMID: 25170091 DOI: 10.1161/circresaha.114.304855] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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454
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Fu XL, Gao DS. Endoplasmic reticulum proteins quality control and the unfolded protein response: the regulative mechanism of organisms against stress injuries. Biofactors 2014; 40:569-85. [PMID: 25530003 DOI: 10.1002/biof.1194] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/25/2014] [Indexed: 12/21/2022]
Abstract
The endoplasmic reticulum is the cellular compartment in which secretory proteins are synthesized and folded. Perturbations of endoplasmic reticulum homeostasis lead to the accumulation of unfolded proteins. The activation of the unfolded protein response during endoplasmic reticulum stress transmits information about the status of protein folding to the cytosol and nucleus. The unfolded protein response leads to the upregulation of genes encoding endoplasmic reticulum chaperones, attenuation of translation, and initiation of the endoplasmic reticulum quality control system to restore endoplasmic reticulum homeostasis. When the unfolded protein response is insufficient to rebuild the steady state in endoplasmic reticulum, the programmed cell death or apoptosis would be initiated, by triggering cell injuries, even to cell death through apoptosis signals. In this review, we briefly outline research on the chaperones and foldases conserved in eukaryotes and plants, and describe the general principles and mechanisms of the endoplasmic reticulum quality control and the unfolded protein response. We describe the current models for the molecular mechanism of the unfolded protein response in plants, and emphasize the role of inositol requiring enzyme-1-dependent network in the unfolded protein response. Finally, we give a general overview of the directions for future research on the unfolded protein response in plants and its role in the response to environmental stresses.
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Affiliation(s)
- Xi Ling Fu
- Division of National Research Center for Apple Engineering and Technology, Shandong Agricultural University, Tai'an, Shandong, China; Division of State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, China
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455
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Cho YM, Kwak SN, Joo NS, Kim DH, Lee AH, Kim KS, Seo JB, Jeong SW, Kwon OJ. X-box binding protein 1 is a novel key regulator of peroxisome proliferator-activated receptor γ2. FEBS J 2014; 281:5132-46. [PMID: 25223794 DOI: 10.1111/febs.13052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 08/10/2014] [Accepted: 09/12/2014] [Indexed: 01/08/2023]
Abstract
X-box binding protein 1 (XBP1), a transcription factor of the unfolded protein response, plays various roles in many biological processes. We examined its pro-adipogenic activity and target genes during adipogenic differentiation in wild-type and genetically modified 3T3-L1 cells. Signalling pathways that contribute to Xbp1 mRNA splicing, and the correlation of the transcriptionally active XBP1 isoform (XBP1s) level with body mass index and the level of peroxisome proliferator-activated receptor γ2 (PPARγ2) in human adipose tissues were also examined. The mRNA and nuclear protein expression levels of XBP1s increased immediately following hormonal induction of adipogenesis, reaching a peak at 6 h. Results from cDNA microarray and gene expression analyses using genetically modified cells indicated that PPARγ2 was a principal target of XBP1s. The XBP1s-specific binding motif, which is distinct from the CCAAT/enhancer-binding protein α binding site, was identified in the PPARγ2 promoter by site-directed mutagenesis. Fetal bovine serum, insulin, 3-isobutyl-1-methylxanthine and dexamethasone contributed independently to Xbp1 mRNA splicing. In human subcutaneous adipose tissues, the levels of both Xbp1s and Pparγ2 mRNA increased proportionally with body mass index, and there was a significant positive correlation between the two genes. These data suggest for the first time that positive regulation of PPARγ2 is a principal mechanism of XBP1s-mediated adipogenesis in 3T3-L1 cells.
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Affiliation(s)
- Yoon Mi Cho
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Korea
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456
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Chiang WC, Kroeger H, Sakami S, Messah C, Yasumura D, Matthes MT, Coppinger JA, Palczewski K, LaVail MM, Lin JH. Robust Endoplasmic Reticulum-Associated Degradation of Rhodopsin Precedes Retinal Degeneration. Mol Neurobiol 2014; 52:679-95. [PMID: 25270370 DOI: 10.1007/s12035-014-8881-8] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 08/25/2014] [Indexed: 12/18/2022]
Abstract
Rhodopsin is a G protein-coupled receptor essential for vision and rod photoreceptor viability. Disease-associated rhodopsin mutations, such as P23H rhodopsin, cause rhodopsin protein misfolding and trigger endoplasmic reticulum (ER) stress, activating the unfolded protein response (UPR). The pathophysiologic effects of ER stress and UPR activation on photoreceptors are unclear. Here, by examining P23H rhodopsin knock-in mice, we found that the UPR inositol-requiring enzyme 1 (IRE1) signaling pathway is strongly activated in misfolded rhodopsin-expressing photoreceptors. IRE1 significantly upregulated ER-associated protein degradation (ERAD), triggering pronounced P23H rhodopsin degradation. Rhodopsin protein loss occurred as soon as photoreceptors developed, preceding photoreceptor cell death. By contrast, IRE1 activation did not affect JNK signaling or rhodopsin mRNA levels. Interestingly, pro-apoptotic signaling from the PERK UPR pathway was also not induced. Our findings reveal that an early and significant pathophysiologic effect of ER stress in photoreceptors is the highly efficient elimination of misfolded rhodopsin protein. We propose that early disruption of rhodopsin protein homeostasis in photoreceptors could contribute to retinal degeneration.
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Affiliation(s)
- Wei-Chieh Chiang
- Department of Pathology, University of California, San Diego, 9500 Gilman Dr., La Jolla, San Diego, CA, 92093-0612, USA
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457
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Endoplasmic reticulum stress responses in Leishmania. Mol Biochem Parasitol 2014; 197:1-8. [PMID: 25224909 DOI: 10.1016/j.molbiopara.2014.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 08/14/2014] [Accepted: 09/05/2014] [Indexed: 11/23/2022]
Abstract
Perturbation of endoplasmic reticulum (ER) homeostasis can lead to an accumulation of misfolded proteins within the ER lumen causing initiation of ER stress. To reestablish homeostasis and mitigate the stress, a series of adaptive intracellular signaling pathways termed the unfolded protein response (UPR) are activated. ER stress is of considerable interest to parasitologists because it takes place in parasites subjected to adverse environmental conditions. During a digenetic lifestyle, Leishmania parasites encounter and adapt to harsh environmental conditions that provide potential triggers of ER stress. These include nutrient deficiency, hypoxia, oxidative stress, changing pH, and shifts in temperature. Protozoan human pathogens, including the causative agents of trypanosomiasis, leishmaniasis, toxoplasmosis and malaria, contain a minimal conventional UPR network relative to higher eukaryotic cells. Three different signaling pathways in the ER stress response have been described in trypanosomatids: these pathways involve (i) the down-regulation of translation by a protein kinase RNA-like ER kinase (PERK), (ii) the ER-associated degradation (ERAD) pathway, and (iii) the spliced leader silencing (SLS) pathway and its target mRNAs. Under short-term ER stress, signaling from PERK activates autophagy, a cell survival response. But both chronic and unresolved ER stresses lead to initiation of apoptotic events and eventual cell death. This review presents the current understanding of the ER stress response in Leishmania with an emphasis on protein folding and ER quality control, unfolded protein response, autophagy as well as apoptosis in reference to the mammalian system.
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458
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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: 26] [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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459
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Abstract
Protein quality control is regulated by the proteostasis network and cell stress response pathways to promote cellular health. In this review, van Oosten-Hawle and Morimoto cover recent advances in model systems that reveal how communication between subcellular compartments and across different cells and tissues maintains a functional proteome during stress. The authors propose that transcellular stress signaling provides a critical control mechanism for the proteostasis network to maintain organismal health and life span. Protein quality control is essential in all organisms and regulated by the proteostasis network (PN) and cell stress response pathways that maintain a functional proteome to promote cellular health. In this review, we describe how metazoans employ multiple modes of cell-nonautonomous signaling across tissues to integrate and transmit the heat-shock response (HSR) for balanced expression of molecular chaperones. The HSR and other cell stress responses such as the unfolded protein response (UPR) can function autonomously in single-cell eukaryotes and tissue culture cells; however, within the context of a multicellular animal, the PN is regulated by cell-nonautonomous signaling through specific sensory neurons and by the process of transcellular chaperone signaling. These newly identified forms of stress signaling control the PN between neurons and nonneuronal somatic tissues to achieve balanced tissue expression of chaperones in response to environmental stress and to ensure that metastable aggregation-prone proteins expressed within any single tissue do not generate local proteotoxic risk. Transcellular chaperone signaling leads to the compensatory expression of chaperones in other somatic tissues of the animal, perhaps preventing the spread of proteotoxic damage. Thus, communication between subcellular compartments and across different cells and tissues maintains proteostasis when challenged by acute stress and upon chronic expression of metastable proteins. We propose that transcellular chaperone signaling provides a critical control step for the PN to maintain cellular and organismal health span.
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460
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Maas NL, Diehl JA. Molecular pathways: the PERKs and pitfalls of targeting the unfolded protein response in cancer. Clin Cancer Res 2014; 21:675-9. [PMID: 25182515 DOI: 10.1158/1078-0432.ccr-13-3239] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The endoplasmic reticulum (ER) is a highly specialized organelle that provides an oxidizing, profolding environment for protein synthesis and maturation. The ER also hosts a dynamic signaling network that can sense and respond to physiologic changes that affect its environment, thereby influencing overall cell fate. Limitation of nutrients and oxygen have a direct effect on the efficiency of protein folding in the ER, and are classic inducers of the ER resident signaling pathway, the unfolded protein response (UPR). Not only does the UPR regulate ER homeostasis in normal cells experiencing such stress, but strong evidence also suggests that tumor cells can co-opt the cytoprotective aspects of this response to survive the hypoxic, nutrient-restricted conditions of the tumor microenvironment.
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Affiliation(s)
- Nancy L Maas
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - J Alan Diehl
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, Pennsylvania.
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461
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Cajaninstilbene acid protects corticosterone-induced injury in PC12 cells by inhibiting oxidative and endoplasmic reticulum stress-mediated apoptosis. Neurochem Int 2014; 78:43-52. [PMID: 25193317 DOI: 10.1016/j.neuint.2014.08.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 08/21/2014] [Accepted: 08/23/2014] [Indexed: 01/13/2023]
Abstract
It has been reported that high corticosterone level could damage the normal hippocampal neurons both in vitro and in vivo. Furthermore, high concentration of corticosterone induced impair in PC12 cells has been widely used as in vitro model to screen neuroprotective agents. Cajaninstilbene acid (CSA), a natural stilbene isolated from Cajanus cajan leaves, has various activities. In present study, we investigated the effect of CSA on corticosterone-induced cell apoptosis and explored its possible signaling pathways in PC12 cells. We demonstrated that pretreatment with CSA at the concentrations of 1-8 μmol/L remarkably reduced the cytotoxicity induced by 200 μmol/L of corticosterone in PC12 cells by MTT, and further confirmed the neuroprotection by Hoechst 33342 and PI double staining and lactate dehydrogenase release (LDH) assay at the concentration of 8 μmol/L. Moreover, the cytoprotection of CSA was proved to be associated with the homeostasis of intracellular Ca(2+), relieving corticosterone-induced oxidative stress by decreasing the contents of ROS and malondialdehyde (MDA), increasing the activities of superoxide dismutase (SOD) and catalase (CAT), and the stabilization of ER stress via down-regulating the expression of ER chaperone protein glucose-regulated protein 78 (GRP78), ER stress associated transcription factor C/EBP homologous protein (CHOP/GADD153), and the X box-binding protein-1 (XBP-1), as well as the expression of ER stress-specific protein caspase-12 and its downstream protein caspase-9. Considering all the findings, it is suggested that the neuroprotective activity of CSA against the impairment induced by corticosterone in PC12 cells was through the inhibition of oxidative stress and ER stress-mediated pathway.
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462
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Mardones P, Martínez G, Hetz C. Control of systemic proteostasis by the nervous system. Trends Cell Biol 2014; 25:1-10. [PMID: 25174273 DOI: 10.1016/j.tcb.2014.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/01/2014] [Accepted: 08/04/2014] [Indexed: 10/24/2022]
Abstract
Maintenance of organismal homeostasis depends on the integration of intracellular and external signals, involving the ability to detect molecular perturbations. An explosion of studies in model organisms indicates the occurrence of dynamic communication between alarm pathways engaged by protein-folding stress in neurons that activate adaptive programs in peripheral organs to control cellular proteostasis. Here we review emerging concepts that highlight the contribution of the proteostasis network to the regulation of several aspects of animal physiology through central integration of signals spanning multiple tissues and organs. These recent findings uncover a new layer of functional interrelation between cells that handle and orchestrate the global maintenance of the proteome at the organismal level in a cell-nonautonomous manner.
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Affiliation(s)
- Pablo Mardones
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Gabriela Martínez
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile, Santiago, Chile; Neurounion Biomedical Foundation, CENPAR, Santiago, Chile; Department of Immunology and Infectious diseases, Harvard School of Public Health, Boston, MA, USA.
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463
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Lu Y, Liang FX, Wang X. A synthetic biology approach identifies the mammalian UPR RNA ligase RtcB. Mol Cell 2014; 55:758-70. [PMID: 25087875 DOI: 10.1016/j.molcel.2014.06.032] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/01/2014] [Accepted: 06/25/2014] [Indexed: 01/21/2023]
Abstract
Signaling in the ancestral branch of the unfolded protein response (UPR) is initiated by unconventional splicing of HAC1/XBP1 mRNA during endoplasmic reticulum (ER) stress. In mammals, IRE1α has been known to cleave the XBP1 intron. However, the enzyme responsible for ligation of two XBP1 exons remains unknown. Using an XBP1 splicing-based synthetic circuit, we identify RtcB as the primary UPR RNA ligase. In RtcB knockout cells, XBP1 mRNA splicing is defective during ER stress. Genetic rescue and in vitro splicing show that the RNA ligase activity of RtcB is directly required for the splicing of XBP1 mRNA. Taken together, these data demonstrate that RtcB is the long-sought RNA ligase that catalyzes unconventional RNA splicing during the mammalian UPR.
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Affiliation(s)
- Yanyan Lu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Feng-Xia Liang
- Office of Collaborative Science Microscopy Core, New York University School of Medicine, New York, NY 10016, USA
| | - Xiaozhong Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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464
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Minoia M, Boncoraglio A, Vinet J, Morelli FF, Brunsting JF, Poletti A, Krom S, Reits E, Kampinga HH, Carra S. BAG3 induces the sequestration of proteasomal clients into cytoplasmic puncta: implications for a proteasome-to-autophagy switch. Autophagy 2014; 10:1603-21. [PMID: 25046115 DOI: 10.4161/auto.29409] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Eukaryotic cells use autophagy and the ubiquitin-proteasome system as their major protein degradation pathways. Upon proteasomal impairment, cells switch to autophagy to ensure proper clearance of clients (the proteasome-to-autophagy switch). The HSPA8 and HSPA1A cochaperone BAG3 has been suggested to be involved in this switch. However, at present it is still unknown whether and to what extent BAG3 can indeed reroute proteasomal clients to the autophagosomal pathway. Here, we show that BAG3 induces the sequestration of ubiquitinated clients into cytoplasmic puncta colabeled with canonical autophagy linkers and markers. Following proteasome inhibition, BAG3 upregulation significantly contributes to the compensatory activation of autophagy and to the degradation of the (poly)ubiquitinated proteins. BAG3 binding to the ubiquitinated clients occurs through the BAG domain, in competition with BAG1, another BAG family member, that normally directs ubiquitinated clients to the proteasome. Therefore, we propose that following proteasome impairment, increasing the BAG3/BAG1 ratio ensures the "BAG-instructed proteasomal to autophagosomal switch and sorting" (BIPASS).
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Affiliation(s)
- Melania Minoia
- Department of Cell Biology; University Medical Center Groningen; University of Groningen; Groningen, The Netherlands
| | - Alessandra Boncoraglio
- Department of Cell Biology; University Medical Center Groningen; University of Groningen; Groningen, The Netherlands; Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB); Università degli Studi di Milano; Centro di Eccellenza sulle Patologie Neurodegenerative (CEND); Milano, Italy
| | - Jonathan Vinet
- Dipartimento di Scienze Biomediche; Metaboliche e Neuroscienze; Università degli Studi di Modena e Reggio Emilia; Modena, Italy
| | - Federica F Morelli
- Dipartimento di Scienze Biomediche; Metaboliche e Neuroscienze; Università degli Studi di Modena e Reggio Emilia; Modena, Italy
| | - Jeanette F Brunsting
- Department of Cell Biology; University Medical Center Groningen; University of Groningen; Groningen, The Netherlands
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB); Università degli Studi di Milano; Centro di Eccellenza sulle Patologie Neurodegenerative (CEND); Milano, Italy
| | - Sabine Krom
- Departments of Cell Biology and Histology; University of Amsterdam; Academic Medical Center; Amsterdam, The Netherlands
| | - Eric Reits
- Departments of Cell Biology and Histology; University of Amsterdam; Academic Medical Center; Amsterdam, The Netherlands
| | - Harm H Kampinga
- Department of Cell Biology; University Medical Center Groningen; University of Groningen; Groningen, The Netherlands
| | - Serena Carra
- Department of Cell Biology; University Medical Center Groningen; University of Groningen; Groningen, The Netherlands; Dipartimento di Scienze Biomediche; Metaboliche e Neuroscienze; Università degli Studi di Modena e Reggio Emilia; Modena, Italy
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465
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Yuan L, Yu J, Li X, Feng J, Yin C, Wang X. IRE1α knockdown rescues tunicamycin-induced developmental defects and apoptosis in Xenopus laevis. J Biomed Res 2014; 28:275-81. [PMID: 25050111 PMCID: PMC4102841 DOI: 10.7555/jbr.28.20120075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 09/06/2012] [Accepted: 12/04/2013] [Indexed: 11/29/2022] Open
Abstract
Inositol requiring enzyme-1 (IRE1) is highly conserved from yeasts to humans. Upon endoplasmic reticulum (ER) stress, IRE1 activates X-box-binding protein 1 (XBP1) by unconventional splicing of XBP1 mRNA, which activates unfolded protein response (UPR) to restore ER homeostasis. In mice, IRE1α plays an essential role in extraembryonic tissues. However, its precise action during the early stage of development is unknown. In this study, the gain and loss-of-function analyses were used to investigate the function of Xenopus IRE1α (xIRE1α). The effects of xIRE1α during embryo development were detected with RT-PCR and whole mount in situ hybridization. ER stress was induced by tunicamycin. The apoptotic cells were measured by TUNNEL assays. Although both gain and loss of xIRE1α function had no significant effect on Xenopus embryogenesis, knockdown of xIRE1α could rescue tunicamycin-induced developmental defects and apoptosis. The finding indicates that xIRE1α is not required for embryogenesis but is required for tunicamycin-induced developmental defects and apoptosis in Xenopus laevis.
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Affiliation(s)
- Li Yuan
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
| | - Jin Yu
- Department of Hematology, Friendship hospital of yili kazakh prefecture, Yining, Xinjiang 835000, China.
| | - Xinxin Li
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
| | - Jiaojiao Feng
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
| | - Chenyang Yin
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
| | - Xinru Wang
- Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
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466
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N-octanoyl dopamine treatment of endothelial cells induces the unfolded protein response and results in hypometabolism and tolerance to hypothermia. PLoS One 2014; 9:e99298. [PMID: 24926788 PMCID: PMC4057113 DOI: 10.1371/journal.pone.0099298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/13/2014] [Indexed: 12/11/2022] Open
Abstract
Aim N-acyl dopamines (NADD) are gaining attention in the field of inflammatory and neurological disorders. Due to their hydrophobicity, NADD may have access to the endoplasmic reticulum (ER). We therefore investigated if NADD induce the unfolded protein response (UPR) and if this in turn influences cell behaviour. Methods Genome wide gene expression profiling, confirmatory qPCR and reporter assays were employed on human umbilical vein endothelial cells (HUVEC) to validate induction of UPR target genes and UPR sensor activation by N-octanoyl dopamine (NOD). Intracellular ATP, apoptosis and induction of thermotolerance were used as functional parameters to assess adaptation of HUVEC. Results NOD, but not dopamine dose dependently induces the UPR. This was also found for other synthetic NADD. Induction of the UPR was dependent on the redox activity of NADD and was not caused by selective activation of a particular UPR sensor. UPR induction did not result in cell apoptosis, yet NOD strongly impaired cell proliferation by attenuation of cells in the S-G2/M phase. Long-term treatment of HUVEC with low NOD concentration showed decreased intracellular ATP concentration paralleled with activation of AMPK. These cells were significantly more resistant to cold inflicted injury. Conclusions We provide for the first time evidence that NADD induce the UPR in vitro. It remains to be assessed if UPR induction is causally associated with hypometabolism and thermotolerance. Further pharmacokinetic studies are warranted to address if the NADD concentrations used in vitro can be obtained in vivo and if this in turn shows therapeutic efficacy.
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467
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Groenendyk J, Peng Z, Dudek E, Fan X, Mizianty MJ, Dufey E, Urra H, Sepulveda D, Rojas-Rivera D, Lim Y, Kim DH, Baretta K, Srikanth S, Gwack Y, Ahnn J, Kaufman RJ, Lee SK, Hetz C, Kurgan L, Michalak M. Interplay between the oxidoreductase PDIA6 and microRNA-322 controls the response to disrupted endoplasmic reticulum calcium homeostasis. Sci Signal 2014; 7:ra54. [PMID: 24917591 DOI: 10.1126/scisignal.2004983] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The disruption of the energy or nutrient balance triggers endoplasmic reticulum (ER) stress, a process that mobilizes various strategies, collectively called the unfolded protein response (UPR), which reestablish homeostasis of the ER and cell. Activation of the UPR stress sensor IRE1α (inositol-requiring enzyme 1α) stimulates its endoribonuclease activity, leading to the generation of the mRNA encoding the transcription factor XBP1 (X-box binding protein 1), which regulates the transcription of genes encoding factors involved in controlling the quality and folding of proteins. We found that the activity of IRE1α was regulated by the ER oxidoreductase PDIA6 (protein disulfide isomerase A6) and the microRNA miR-322 in response to disruption of ER Ca2+ homeostasis. PDIA6 interacted with IRE1α and enhanced IRE1α activity as monitored by phosphorylation of IRE1α and XBP1 mRNA splicing, but PDIA6 did not substantially affect the activity of other pathways that mediate responses to ER stress. ER Ca2+ depletion and activation of store-operated Ca2+ entry reduced the abundance of the microRNA miR-322, which increased PDIA6 mRNA stability and, consequently, IRE1α activity during the ER stress response. In vivo experiments with mice and worms showed that the induction of ER stress correlated with decreased miR-322 abundance, increased PDIA6 mRNA abundance, or both. Together, these findings demonstrated that ER Ca2+, PDIA6, IRE1α, and miR-322 function in a dynamic feedback loop modulating the UPR under conditions of disrupted ER Ca2+ homeostasis.
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Affiliation(s)
- Jody Groenendyk
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S7, Canada
| | - Zhenling Peng
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Elzbieta Dudek
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S7, Canada
| | - Xiao Fan
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Marcin J Mizianty
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Estefanie Dufey
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Hery Urra
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Denisse Sepulveda
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Diego Rojas-Rivera
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Yunki Lim
- College of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Korea
| | - Do Han Kim
- College of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Korea
| | - Kayla Baretta
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S7, Canada
| | - Sonal Srikanth
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yousang Gwack
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Joohong Ahnn
- Department of Life Science, BK21 PLUS Life Science for BDR team, The Research Institute of Natural Sciences, Hanyang University, Seoul 133-791, Korea
| | - Randal J Kaufman
- Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Cancer Center, Sanford Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Sun-Kyung Lee
- Department of Life Science, BK21 PLUS Life Science for BDR team, The Research Institute of Natural Sciences, Hanyang University, Seoul 133-791, Korea
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile. Neurounion Biomedical Foundation, Santiago, Chile
| | - Lukasz Kurgan
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2S7, Canada.
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468
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Zhang Y, Liu CM, Cao XC, Zang Y, Zhou YB, Li J. Involvement of transcription factor XBP1s in the resistance of HDAC6 inhibitor Tubastatin A to superoxidation via acetylation-mediated proteasomal degradation. Biochem Biophys Res Commun 2014; 450:433-9. [PMID: 24909686 DOI: 10.1016/j.bbrc.2014.05.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 05/28/2014] [Indexed: 10/25/2022]
Abstract
HDAC6 is a major cytoplasmic deacetylase. XBP1s is a basic-region leucine zipper (bZIP) transcriptional factor. Despite their mutual involvement in the anti-oxidative process, there are no reports about their inter-protein interactions so far. Here we identified a direct link between HDAC6 inhibition and XBP1s transcription activity in anti-oxidative damage. We showed that the specific HDAC6 inhibitor Tubastatin A could up-regulate XBP1s transcriptional activity, thereby increasing anti-oxidative genes expression. Moreover, knock down of XBP1s could significantly abolish the cell growth protection afforded by Tubastatin A. We hypothesize that Tubastatin A acts to increase XBP1s protein levels that are dependent on its HDAC6 deacetylase inhibition via a mechanism involving acetylation-mediated proteasomal degradation, providing novel mechanistic insight into the anti-oxidative effects of HDAC6 inhibition.
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Affiliation(s)
- Yue Zhang
- School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China; National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Chang-mei Liu
- School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China; National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xian-cao Cao
- School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China; National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yi Zang
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yu-bo Zhou
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
| | - Jia Li
- School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China; National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
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469
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Wolff S, Weissman JS, Dillin A. Differential scales of protein quality control. Cell 2014; 157:52-64. [PMID: 24679526 DOI: 10.1016/j.cell.2014.03.007] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 02/06/2023]
Abstract
Proteins are notorious for their unpleasant behavior-continually at risk of misfolding, collecting damage, aggregating, and causing toxicity and disease. To counter these challenges, cells have evolved elaborate chaperone and quality control networks that can resolve damage at the level of the protein, organelle, cell, or tissue. On the smallest scale, the integrity of individual proteins is monitored during their synthesis. On a larger scale, cells use compartmentalized defenses and networks of communication, capable sometimes of signaling between cells, to respond to changes in the proteome's health. Together, these layered defenses help protect cells from damaged proteins.
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Affiliation(s)
- Suzanne Wolff
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, California Institute of Quantitative Biology, Center for RNA Systems Biology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Andrew Dillin
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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470
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Yadav RK, Chae SW, Kim HR, Chae HJ. Endoplasmic reticulum stress and cancer. J Cancer Prev 2014; 19:75-88. [PMID: 25337575 PMCID: PMC4204165 DOI: 10.15430/jcp.2014.19.2.75] [Citation(s) in RCA: 301] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 06/07/2014] [Accepted: 06/07/2014] [Indexed: 12/14/2022] Open
Abstract
The endoplasmic reticulum (ER) is the principal organelle responsible for multiple cellular functions including protein folding and maturation and the maintenance of cellular homeostasis. ER stress is activated by a variety of factors and triggers the unfolded protein response (UPR), which restores homeostasis or activates cell death. Multiple studies have clarified the link between ER stress and cancer, and particularly the involvement of the UPR. The UPR seems to adjust the paradoxical microenvironment of cancer and, as such, is one of resistance mechanisms against cancer therapy. This review describes the activity of different UPRs involved in tumorigenesis and resistance to cancer therapy.
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Affiliation(s)
- Raj Kumar Yadav
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Jeonju, Chonbuk, Korea
| | - Soo-Wan Chae
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Jeonju, Chonbuk, Korea
| | - Hyung-Ryong Kim
- Department of Dental Pharmacology, College of Dentistry, Wonkwang University, Iksan, Chonbuk, Korea
| | - Han Jung Chae
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Jeonju, Chonbuk, Korea
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471
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Pluquet O, Dejeans N, Chevet E. Watching the clock: endoplasmic reticulum-mediated control of circadian rhythms in cancer. Ann Med 2014; 46:233-43. [PMID: 24491143 DOI: 10.3109/07853890.2013.874664] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In the past 20 years both the circadian clock and endoplasmic reticulum (ER) stress signaling have emerged as major players in oncogenesis and cancer development. Although several lines of evidence have established functional links between these two molecular pathways, their interconnection and the subsequent functional implications in cancer development remain to be fully characterized. Herein, we provide an extensive review of the literature depicting the molecular connectivity linking ER stress signaling and the circadian clock and elaborate on the potential use of these functional interactions in cancer therapeutics.
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Affiliation(s)
- Olivier Pluquet
- Institut de Biologie de Lille, CNRS UMR8161/Universités Lille 1 et Lille 2/Institut Pasteur de Lille , 1, rue du Pr. Calmette, BP 447, 59021 Lille , France
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472
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Beukes N, Levendal RA, Frost CL. Selected terpenoids from medicinal plants modulate endoplasmic reticulum stress in metabolic disorders. J Pharm Pharmacol 2014; 66:1505-25. [DOI: 10.1111/jphp.12267] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/16/2014] [Indexed: 12/20/2022]
Abstract
Abstract
Objectives
The majority of research performed on cellular stress and apoptosis focuses on mitochondrial dysfunction; however, the importance of the endoplasmic reticulum dysfunction and the link to metabolic diseases has gained a substantial interest. This review focuses on the potential of terpenoids to influence endoplasmic reticulum stress and the possible role terpenoids play as the treatment of metabolic diseases.
Key findings
Metabolic diseases develop as a result of a cascade of cellular pathways. In most cases, cells are able to compensate for the disruption of the cellular homeostasis although the initiation of response pathways; however, chronic stress initiates apoptotic pathways. This reviewed (1) showed the importance of phytoterpenoids to influence endoplasmic reticulum (ER) stress and homeostasis, (2) showed how regulating ER stress affect the cell survival and death, and (3) highlighted some examples of how the progression of metabolic diseases can be influenced by ER.
Summary
Due to the substantial number of terpenoids that have been identified in literature, this review gave examples of 21 terpenoids that have been documented to have an effect on the different proteins associated with ER stress, how these plant terpenoids influence ER dysfunction and metabolic diseases such as diabetes, cancer, liver, and neurological diseases and parasitic infections.
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Affiliation(s)
- Natasha Beukes
- Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
| | - Ruby-Ann Levendal
- Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
| | - Carminita L Frost
- Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
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473
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Abstract
The endoplasmic reticulum (ER) is an important player in regulating protein synthesis and lipid metabolism. Perturbation of ER homeostasis, referred as “ER stress,” has been linked to numerous pathological conditions, such as inflammation, cardiovascular diseases, and metabolic disorders. The liver plays a central role in regulating nutrient and lipid metabolism. Accumulating evidence implicates that ER stress disrupts lipid metabolism and induces hepatic lipotoxicity. Here, we review the major ER stress signaling pathways, how ER stress contributes to the dysregulation of hepatic lipid metabolism, and the potential causative mechanisms of ER stress in hepatic lipotoxicity. Understanding the role of ER stress in hepatic metabolism may lead to the identification of new therapeutic targets for metabolic diseases.
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Affiliation(s)
- Huiping Zhou
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond VA, USA ; McGuire Veterans Affairs Medical Center, Richmond VA, USA
| | - Runping Liu
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond VA, USA
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474
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The IRE1α-XBP1 pathway regulates metabolic stress-induced compensatory proliferation of pancreatic β-cells. Cell Res 2014; 24:1137-40. [PMID: 24797433 DOI: 10.1038/cr.2014.55] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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475
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ATF3 attenuates cyclosporin A-induced nephrotoxicity by downregulating CHOP in HK-2 cells. Biochem Biophys Res Commun 2014; 448:182-8. [DOI: 10.1016/j.bbrc.2014.04.083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 04/16/2014] [Indexed: 01/22/2023]
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476
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Coelho DS, Domingos PM. Physiological roles of regulated Ire1 dependent decay. Front Genet 2014; 5:76. [PMID: 24795742 PMCID: PMC3997004 DOI: 10.3389/fgene.2014.00076] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/24/2014] [Indexed: 12/17/2022] Open
Abstract
Inositol-requiring enzyme 1 (Ire1) is an important transducer of the unfolded protein response (UPR) that is activated by the accumulation of misfolded proteins in the endoplamic reticulum (ER stress). Activated Ire1 mediates the splicing of an intron from the mRNA of Xbp1, causing a frame-shift during translation and introducing a new carboxyl domain in the Xbp1 protein, which only then becomes a fully functional transcription factor. Studies using cell culture systems demonstrated that Ire1 also promotes the degradation of mRNAs encoding mostly ER-targeted proteins, to reduce the load of incoming ER “client” proteins during ER stress. This process was called RIDD (regulated Ire1-dependent decay), but its physiological significance remained poorly characterized beyond cell culture systems. Here we review several recent studies that have highlighted the physiological roles of RIDD in specific biological paradigms, such as photoreceptor differentiation in Drosophila or mammalian liver and endocrine pancreas function. These studies demonstrate the importance of RIDD in tissues undergoing intense secretory function and highlight the physiologic role of RIDD during UPR activation in cells and organisms.
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Affiliation(s)
- Dina S Coelho
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Oeiras, Portugal
| | - Pedro M Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Oeiras, Portugal
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477
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Site-specific association with host and viral chromatin by Kaposi's sarcoma-associated herpesvirus LANA and its reversal during lytic reactivation. J Virol 2014; 88:6762-77. [PMID: 24696474 DOI: 10.1128/jvi.00268-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Latency-associated nuclear antigen (LANA), a multifunctional protein expressed by the Kaposi sarcoma-associated herpesvirus (KSHV) in latently infected cells, is required for stable maintenance of the viral episome. This is mediated by two interactions: LANA binds to specific sequences (LBS1 and LBS2) on viral DNA and also engages host histones, tethering the viral genome to host chromosomes in mitosis. LANA has also been suggested to affect host gene expression, but both the mechanism(s) and role of this dysregulation in KSHV biology remain unclear. Here, we have examined LANA interactions with host chromatin on a genome-wide scale using chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) and show that LANA predominantly targets human genes near their transcriptional start sites (TSSs). These host LANA-binding sites are generally found within transcriptionally active promoters and display striking overrepresentation of a consensus DNA sequence virtually identical to the LANA-binding site 1 (LBS1) motif in KSHV DNA. Comparison of the ChIP-seq profile with whole-transcriptome (high-throughput sequencing of RNA transcripts [RNA-seq]) data reveals that few of the genes that are differentially regulated in latent infection are occupied by LANA at their promoters. This suggests that direct LANA binding to promoters is not the prime determinant of altered host transcription in KSHV-infected cells. Most surprisingly, the association of LANA to both host and viral DNA is strongly disrupted during the lytic cycle of KSHV. This disruption can be prevented by the inhibition of viral DNA synthesis, suggesting the existence of novel and potent regulatory mechanisms linked to either viral DNA replication or late gene expression. IMPORTANCE Here, we employ complementary genome-wide analyses to evaluate the distribution of the highly abundant latency-associated nuclear antigen, LANA, on the host genome and its impact on host gene expression during KSHV latent infection. Combined, ChIP-seq and RNA-seq reveal that LANA accumulates at active gene promoters that harbor specific short DNA sequences that are highly reminiscent of its cognate binding sites in the virus genome. Unexpectedly, we found that such association does not lead to remodeling of global host transcription during latency. We also report for the first time that LANA's ability to bind host and viral chromatin is highly dynamic and is disrupted in cells undergoing an extensive lytic reactivation. This therefore suggests that the association of LANA to chromatin during a productive infection cycle is controlled by a new regulatory mechanism.
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478
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The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells. Nat Biotechnol 2014. [PMID: 24658644 DOI: 10.1038/nbt.2859.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Defining the transcriptional dynamics of a temporal process such as cell differentiation is challenging owing to the high variability in gene expression between individual cells. Time-series gene expression analyses of bulk cells have difficulty distinguishing early and late phases of a transcriptional cascade or identifying rare subpopulations of cells, and single-cell proteomic methods rely on a priori knowledge of key distinguishing markers. Here we describe Monocle, an unsupervised algorithm that increases the temporal resolution of transcriptome dynamics using single-cell RNA-Seq data collected at multiple time points. Applied to the differentiation of primary human myoblasts, Monocle revealed switch-like changes in expression of key regulatory factors, sequential waves of gene regulation, and expression of regulators that were not known to act in differentiation. We validated some of these predicted regulators in a loss-of function screen. Monocle can in principle be used to recover single-cell gene expression kinetics from a wide array of cellular processes, including differentiation, proliferation and oncogenic transformation.
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479
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The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells. Nat Biotechnol 2014; 32:381-386. [PMID: 24658644 PMCID: PMC4122333 DOI: 10.1038/nbt.2859] [Citation(s) in RCA: 4230] [Impact Index Per Article: 384.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/25/2014] [Indexed: 11/20/2022]
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480
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Abstract
The unfolded protein response (UPR) is fundamental for development and adaption in eukaryotic cells. Arabidopsis has become one of the best model systems to uncover conserved mechanisms of the UPR in multicellular eukaryotes as well as organism-specific regulation of the UPR in plants. Monitoring the UPR in planta is an elemental approach to identifying regulatory components and to revealing molecular mechanisms of the plant UPR. In this chapter, we provide protocols for the induction and analyses of plant UPR at a molecular level in Arabidopsis. Three kinds of ER stress treatment methods and quantitation of the plant UPR activation are described here.
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Affiliation(s)
- Yani Chen
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
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481
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Wu L, Chou M, Zhu S. Unfolded Protein Response and Cancer. Discoveries (Craiova) 2014; 2:e10. [PMID: 32309542 PMCID: PMC6941583 DOI: 10.15190/d.2014.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/13/2014] [Accepted: 03/13/2014] [Indexed: 11/22/2022] Open
Abstract
Physiological stresses, such as hypoxia and oxidative stress, induce protein misfolding in the endoplasmic reticulum (ER). If proteasome degradation fails to remove the misfolded proteins, these proteins accumulate in the ER, triggering the unfolded protein response (UPR). UPR involves a series of responses, such as the suppression of global protein synthesis and the select expression of a set of proteins to reduce ER stress and restore the homeostasis of ER. In different stages of tumor development, hypoxia occurs and UPR is initiated. The roles of UPR in cancer development are complex, involving angiogenesis, cell survival and proliferation. The current knowledge of the molecular mechanisms involved in UPR, particularly its role in the development of cancer, is discussed.
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Affiliation(s)
- Lihua Wu
- School of Life Sciences, State Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Mary Chou
- Advanced Orthomolecular Research Inc., Calgary, Canada
| | - Shudong Zhu
- School of Life Sciences, State Key Laboratory of Medical Genetics, Central South University, Changsha, China
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482
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Hetz C, Mollereau B. Disturbance of endoplasmic reticulum proteostasis in neurodegenerative diseases. Nat Rev Neurosci 2014; 15:233-49. [PMID: 24619348 DOI: 10.1038/nrn3689] [Citation(s) in RCA: 534] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The unfolded protein response (UPR) is a homeostatic mechanism by which cells regulate levels of misfolded proteins in the endoplasmic reticulum (ER). Although it is well characterized in non-neuronal cells, a proliferation of papers over the past few years has revealed a key role for the UPR in normal neuronal function and as an important driver of neurodegenerative diseases. A complex scenario is emerging in which distinct UPR signalling modules have specific and even opposite effects on neurodegeneration depending on the disease context. Here, we provide an overview of the most recent findings addressing the biological relevance of ER stress in the nervous system.
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Affiliation(s)
- Claudio Hetz
- 1] Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. [2] Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Program of Cellular and Molecular Biology, University of Chile, Santiago, Chile. [3] Neurounion Biomedical Foundation, Santiago, Chile. [4] Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
| | - Bertrand Mollereau
- Laboratory of Molecular Biology of the Cell, CNRS UMR5239, Ecole Normale Supérieure de Lyon, UMS3444 Biosciences Lyon Gerland, University of Lyon, Lyon 69364, France
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483
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Verchot J. The ER quality control and ER associated degradation machineries are vital for viral pathogenesis. FRONTIERS IN PLANT SCIENCE 2014; 5:66. [PMID: 24653727 DOI: 10.3389/fpls.2014.00066/abstract] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/07/2014] [Indexed: 05/24/2023]
Abstract
The endoplasmic reticulum (ER) is central to protein production and membrane lipid synthesis. The unfolded protein response (UPR) supports cellular metabolism by ensuring protein quality control in the ER. Most positive strand RNA viruses cause extensive remodeling of membranes and require active membrane synthesis to promote infection. How viruses interact with the cellular machinery controlling membrane metabolism is largely unknown. Furthermore, there is mounting data pointing to the importance of the UPR and ER associated degradation (ERAD) machineries in viral pathogenesis in eukaryotes emerging topic. For many viruses, the UPR is an early event that is essential for persistent infection and benefits virus replication. In addition, many viruses are reported to commandeer ER resident chaperones to contribute to virus replication and intercellular movement. In particular, calreticulin, the ubiquitin machinery, and the 26S proteasome are most commonly identified components of the UPR and ERAD machinery that also regulate virus infection. In addition, researchers have noted a link between UPR and autophagy. It is well accepted that positive strand RNA viruses use autophagic membranes as scaffolds to support replication and assembly. However this topic has yet to be explored using plant viruses. The goal of research on this topic is to uncover how viruses interact with this ER-related machinery and to use this information for designing novel strategies to boost immune responses to virus infection.
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Affiliation(s)
- Jeanmarie Verchot
- Department of Entomology and Plant Pathology, Oklahoma State University Stillwater, OK, USA
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484
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Duran-Aniotz C, Martínez G, Hetz C. Memory loss in Alzheimer's disease: are the alterations in the UPR network involved in the cognitive impairment? Front Aging Neurosci 2014; 6:8. [PMID: 24523695 PMCID: PMC3906588 DOI: 10.3389/fnagi.2014.00008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 01/12/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Claudia Duran-Aniotz
- Faculty of Medicine, Biomedical Neuroscience Institute, University of Chile Santiago, Chile ; Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile Santiago, Chile
| | - Gabriela Martínez
- Faculty of Medicine, Biomedical Neuroscience Institute, University of Chile Santiago, Chile ; Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile Santiago, Chile
| | - Claudio Hetz
- Faculty of Medicine, Biomedical Neuroscience Institute, University of Chile Santiago, Chile ; Program of Cellular and Molecular Biology, Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, University of Chile Santiago, Chile ; Neurounion Biomedical Foundation Santiago, Chile ; Department of Immunology and Infectious diseases, Harvard School of Public Health Boston, MA, USA
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485
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Osorio F, Tavernier SJ, Hoffmann E, Saeys Y, Martens L, Vetters J, Delrue I, De Rycke R, Parthoens E, Pouliot P, Iwawaki T, Janssens S, Lambrecht BN. The unfolded-protein-response sensor IRE-1α regulates the function of CD8α+ dendritic cells. Nat Immunol 2014; 15:248-57. [DOI: 10.1038/ni.2808] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/09/2013] [Indexed: 12/14/2022]
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486
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Sieber J, Jehle AW. Free Fatty acids and their metabolism affect function and survival of podocytes. Front Endocrinol (Lausanne) 2014; 5:186. [PMID: 25386168 PMCID: PMC4209866 DOI: 10.3389/fendo.2014.00186] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 10/13/2014] [Indexed: 12/14/2022] Open
Abstract
Podocyte injury and loss critically contribute to the pathogenesis of proteinuric kidney diseases including diabetic nephropathy. Deregulated lipid metabolism with disturbed free fatty acid (FFA) metabolism is a characteristic of metabolically unhealthy obesity and type 2 diabetes and likely contributes to end-stage kidney disease irrespective of the underlying kidney disease. In the current review, we summarize recent findings related to FFAs and altered renal FFA metabolism with a special focus on podocytes. We will outline the opposing effects of saturated and monounsaturated FFAs and a particular emphasis will be given to the underlying molecular mechanisms involving insulin resistance and endoplasmic reticulum homeostasis. Finally, recent data suggesting a critical role of renal FFA metabolism to adapt to an altered lipid environment will be discussed.
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Affiliation(s)
- Jonas Sieber
- Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- *Correspondence: Jonas Sieber, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA e-mail: ; Andreas Werner Jehle, Department of Biomedicine, Molecular Nephrology, University Hospital Basel, Room 303, Hebelstrasse 20, Basel 4031, Switzerland e-mail:
| | - Andreas Werner Jehle
- Molecular Nephrology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Transplantation Immunology and Nephrology, Department of Internal Medicine, University Hospital Basel, Basel, Switzerland
- *Correspondence: Jonas Sieber, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA e-mail: ; Andreas Werner Jehle, Department of Biomedicine, Molecular Nephrology, University Hospital Basel, Room 303, Hebelstrasse 20, Basel 4031, Switzerland e-mail:
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487
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Targeting the unfolded protein response in neurodegeneration: A new approach to therapy. Neuropharmacology 2014; 76 Pt A:169-74. [DOI: 10.1016/j.neuropharm.2013.08.034] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/23/2013] [Accepted: 08/27/2013] [Indexed: 11/24/2022]
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488
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Verchot J. The ER quality control and ER associated degradation machineries are vital for viral pathogenesis. FRONTIERS IN PLANT SCIENCE 2014; 5:66. [PMID: 24653727 PMCID: PMC3949406 DOI: 10.3389/fpls.2014.00066] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/07/2014] [Indexed: 05/19/2023]
Abstract
The endoplasmic reticulum (ER) is central to protein production and membrane lipid synthesis. The unfolded protein response (UPR) supports cellular metabolism by ensuring protein quality control in the ER. Most positive strand RNA viruses cause extensive remodeling of membranes and require active membrane synthesis to promote infection. How viruses interact with the cellular machinery controlling membrane metabolism is largely unknown. Furthermore, there is mounting data pointing to the importance of the UPR and ER associated degradation (ERAD) machineries in viral pathogenesis in eukaryotes emerging topic. For many viruses, the UPR is an early event that is essential for persistent infection and benefits virus replication. In addition, many viruses are reported to commandeer ER resident chaperones to contribute to virus replication and intercellular movement. In particular, calreticulin, the ubiquitin machinery, and the 26S proteasome are most commonly identified components of the UPR and ERAD machinery that also regulate virus infection. In addition, researchers have noted a link between UPR and autophagy. It is well accepted that positive strand RNA viruses use autophagic membranes as scaffolds to support replication and assembly. However this topic has yet to be explored using plant viruses. The goal of research on this topic is to uncover how viruses interact with this ER-related machinery and to use this information for designing novel strategies to boost immune responses to virus infection.
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Affiliation(s)
- Jeanmarie Verchot
- *Correspondence: Jeanmarie Verchot, Department of Entomology and Plant Pathology, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078, USA e-mail:
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489
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Nguyen TK, Grant S. Dinaciclib (SCH727965) inhibits the unfolded protein response through a CDK1- and 5-dependent mechanism. Mol Cancer Ther 2013; 13:662-74. [PMID: 24362465 DOI: 10.1158/1535-7163.mct-13-0714] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Evidence implicating dysregulation of the IRE1/XBP-1s arm of the unfolded protein response (UPR) in cancer pathogenesis (e.g., multiple myeloma) has prompted the development of IRE1 RNase inhibitors. Here, effects of cyclin-dependent kinase (CDK) inhibitor SCH727965 (dinaciclib) on the IRE1 arm of the UPR were examined in human leukemia and myeloma cells. Exposure of cells to extremely low (e.g., nmol/L) concentrations of SCH727965, a potent inhibitor of CDKs 1/2/5/9, diminished XBP-1s and Grp78 induction by the endoplasmic reticulum (ER) stress-inducers thapsigargin and tunicamycin, while sharply inducing cell death. SCH727965, in contrast to IRE1 RNase inhibitors, inhibited the UPR in association with attenuation of XBP-1s nuclear localization and accumulation rather than transcription, translation, or XBP-1 splicing. Notably, in human leukemia cells, CDK1 and 5 short hairpin RNA (shRNA) knockdown diminished Grp78 and XBP-1s upregulation while increasing thapsigargin lethality, arguing for a functional role for CDK1/5 in activation of the cytoprotective IRE1/XBP-1s arm of the UPR. In contrast, CDK9 or 2 inhibitors or shRNA knockdown failed to downregulate XBP-1s or Grp78. Furthermore, IRE1, XBP-1, or Grp78 knockdown significantly increased thapsigargin lethality, as observed with CDK1/5 inhibition/knockdown. Finally, SCH727965 diminished myeloma cell growth in vivo in association with XBP-1s downregulation. Together, these findings demonstrate that SCH727965 acts at extremely low concentrations to attenuate XBP-1s nuclear accumulation and Grp78 upregulation in response to ER stress inducers. They also highlight a link between specific components of the cell-cycle regulatory apparatus (e.g., CDK1/5) and the cytoprotective IRE1/XBP-1s/Grp78 arm of the UPR that may be exploited therapeutically in UPR-driven malignancies.
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Affiliation(s)
- Tri K Nguyen
- Corresponding Author: Steven Grant, Massey Cancer Center, Virginia Commonwealth University, Room 234, 401 College Street, P.O. Box 980035, Richmond, VA 23298-0035.
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490
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Auf G, Jabouille A, Delugin M, Guérit S, Pineau R, North S, Platonova N, Maitre M, Favereaux A, Vajkoczy P, Seno M, Bikfalvi A, Minchenko D, Minchenko O, Moenner M. High epiregulin expression in human U87 glioma cells relies on IRE1α and promotes autocrine growth through EGF receptor. BMC Cancer 2013; 13:597. [PMID: 24330607 PMCID: PMC3878670 DOI: 10.1186/1471-2407-13-597] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 12/10/2013] [Indexed: 01/20/2023] Open
Abstract
Background Epidermal growth factor (EGF) receptors contribute to the development of malignant glioma. Here we considered the possible implication of the EGFR ligand epiregulin (EREG) in glioma development in relation to the activity of the unfolded protein response (UPR) sensor IRE1α. We also examined EREG status in several glioblastoma cell lines and in malignant glioma. Methods Expression and biological properties of EREG were analyzed in human glioma cells in vitro and in human tumor xenografts with regard to the presence of ErbB proteins and to the blockade of IRE1α. Inactivation of IRE1α was achieved by using either the dominant-negative strategy or siRNA-mediated knockdown. Results EREG was secreted in high amounts by U87 cells, which also expressed its cognate EGF receptor (ErbB1). A stimulatory autocrine loop mediated by EREG was evidenced by the decrease in cell proliferation using specific blocking antibodies directed against either ErbB1 (cetuximab) or EREG itself. In comparison, anti-ErbB2 antibodies (trastuzumab) had no significant effect. Inhibition of IRE1α dramatically reduced EREG expression both in cell culture and in human xenograft tumor models. The high-expression rate of EREG in U87 cells was therefore linked to IRE1α, although being modestly affected by chemical inducers of the endoplasmic reticulum stress. In addition, IRE1-mediated production of EREG did not depend on IRE1 RNase domain, as neither the selective dominant-negative invalidation of the RNase activity (IRE1 kinase active) nor the siRNA-mediated knockdown of XBP1 had significant effect on EREG expression. Finally, chemical inhibition of c-Jun N-terminal kinases (JNK) using the SP600125 compound reduced the ability of cells to express EREG, demonstrating a link between the growth factor production and JNK activation under the dependence of IRE1α. Conclusion EREG may contribute to glioma progression under the control of IRE1α, as exemplified here by the autocrine proliferation loop mediated in U87 cells by the growth factor through ErbB1.
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491
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Arensdorf AM, Diedrichs D, Rutkowski DT. Regulation of the transcriptome by ER stress: non-canonical mechanisms and physiological consequences. Front Genet 2013; 4:256. [PMID: 24348511 PMCID: PMC3844873 DOI: 10.3389/fgene.2013.00256] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/08/2013] [Indexed: 12/29/2022] Open
Abstract
The mammalian unfolded protein response (UPR) is propagated by three ER-resident transmembrane proteins, each of which initiates a signaling cascade that ultimately culminates in production of a transcriptional activator. The UPR was originally characterized as a pathway for upregulating ER chaperones, and a comprehensive body of subsequent work has shown that protein synthesis, folding, oxidation, trafficking, and degradation are all transcriptionally enhanced by the UPR. However, the global reach of the UPR extends to genes involved in diverse physiological processes having seemingly little to do with ER protein folding, and this includes a substantial number of mRNAs that are suppressed by stress rather than stimulated. Through multiple non-canonical mechanisms emanating from each of the UPR pathways, the cell dynamically regulates transcription and mRNA degradation. Here we highlight these mechanisms and their increasingly appreciated impact on physiological processes.
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Affiliation(s)
- Angela M Arensdorf
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine Iowa City, IA, USA
| | - Danilo Diedrichs
- Department of Mathematics and Computer Science, Wheaton College Wheaton, IL, USA
| | - D Thomas Rutkowski
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine Iowa City, IA, USA ; Department of Internal Medicine, University of Iowa Carver College of Medicine Iowa City, IA, USA
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492
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Yang J, Carra S, Zhu WG, Kampinga HH. The regulation of the autophagic network and its implications for human disease. Int J Biol Sci 2013; 9:1121-33. [PMID: 24339733 PMCID: PMC3858585 DOI: 10.7150/ijbs.6666] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 06/28/2013] [Indexed: 12/19/2022] Open
Abstract
Autophagy has attracted a lot of attention in recent years. More and more proteins and signaling pathways have been discovered that somehow feed into the autophagy regulatory pathways. Regulation of autophagy is complex and condition-specific, and in several diseases, autophagic fluxes are changed. Here, we review the most well-established concepts in this field as well as the reported signaling pathways or components which steer the autophagy machinery. Furthermore, we will highlight how autophagic fluxes are changed in various diseases either as cause for or as response to deal with an altered cellular homeostasis and how modulation of autophagy might be used as potential therapy for such diseases.
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Affiliation(s)
- Jing Yang
- 1. Department of Cell Biology; University Medical Center Groningen, University of Groningen; Groningen, The Netherlands. ; 2. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education); Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing 100191, China
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493
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Coelho DS, Cairrão F, Zeng X, Pires E, Coelho AV, Ron D, Ryoo HD, Domingos PM. Xbp1-independent Ire1 signaling is required for photoreceptor differentiation and rhabdomere morphogenesis in Drosophila. Cell Rep 2013; 5:791-801. [PMID: 24183663 PMCID: PMC3858604 DOI: 10.1016/j.celrep.2013.09.046] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 08/28/2013] [Accepted: 09/30/2013] [Indexed: 10/26/2022] Open
Abstract
The unfolded protein response (UPR) is composed by homeostatic signaling pathways that are activated by excessive protein misfolding in the endoplasmic reticulum. Ire1 signaling is an important mediator of the UPR, leading to the activation of the transcription factor Xbp1. Here, we show that Drosophila Ire1 mutant photoreceptors have defects in the delivery of rhodopsin-1 to the rhabdomere and in the secretion of Spacemaker/Eyes Shut into the interrhabdomeral space. However, these defects are not observed in Xbp1 mutant photoreceptors. Ire1 mutant retinas have higher mRNA levels for targets of regulated Ire1-dependent decay (RIDD), including for the fatty acid transport protein (fatp). Importantly, the downregulation of fatp by RNAi rescues the rhodopsin-1 delivery defects observed in Ire1 mutant photoreceptors. Our results show that the role of Ire1 during photoreceptor differentiation is independent of Xbp1 function and demonstrate the physiological relevance of the RIDD mechanism in this specific paradigm.
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Affiliation(s)
- Dina S. Coelho
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Fatima Cairrão
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Xiaomei Zeng
- Department of Cell Biology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | - Elisabete Pires
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ana V. Coelho
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - David Ron
- University of Cambridge, Metabolic Research Laboratory and NIHR Cambridge Biomedical Research Centre, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | - Pedro M. Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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494
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ER Dysfunction and Protein Folding Stress in ALS. Int J Cell Biol 2013; 2013:674751. [PMID: 24324498 PMCID: PMC3845333 DOI: 10.1155/2013/674751] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/02/2013] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most frequent paralytic disease in adults. Most ALS cases are considered sporadic with no clear genetic component. The disruption of protein homeostasis due to chronic stress responses at the endoplasmic reticulum (ER) and the accumulation of abnormal protein inclusions are extensively described in ALS mouse models and patient-derived tissue. Recent studies using pharmacological and genetic manipulation of the unfolded protein response (UPR), an adaptive reaction against ER stress, have demonstrated a complex involvement of the pathway in experimental models of ALS. In addition, quantitative changes in ER stress-responsive chaperones in body fluids have been proposed as possible biomarkers to monitor the disease progression. Here we review most recent advances attributing a causal role of ER stress in ALS.
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495
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Cornejo VH, Pihán P, Vidal RL, Hetz C. Role of the unfolded protein response in organ physiology: Lessons from mouse models. IUBMB Life 2013; 65:962-75. [DOI: 10.1002/iub.1224] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/07/2013] [Indexed: 12/13/2022]
Affiliation(s)
- Víctor Hugo Cornejo
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
| | - Philippe Pihán
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
| | | | - Claudio Hetz
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
- Neurounion Biomedical Foundation; Santiago Chile
- Department of Immunology and Infectious Diseases; Harvard School of Public Health; Boston MA USA
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496
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Shin J, He M, Liu Y, Paredes S, Villanova L, Brown K, Qiu X, Nabavi N, Mohrin M, Wojnoonski K, Li P, Cheng HL, Murphy AJ, Valenzuela DM, Luo H, Kapahi P, Krauss R, Mostoslavsky R, Yancopoulos GD, Alt FW, Chua KF, Chen D. SIRT7 represses Myc activity to suppress ER stress and prevent fatty liver disease. Cell Rep 2013; 5:654-665. [PMID: 24210820 DOI: 10.1016/j.celrep.2013.10.007] [Citation(s) in RCA: 223] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 09/30/2013] [Accepted: 10/03/2013] [Indexed: 12/31/2022] Open
Abstract
Nonalcoholic fatty liver disease is the most common chronic liver disorder in developed countries. Its pathogenesis is poorly understood, and therapeutic options are limited. Here, we show that SIRT7, an NAD(+)-dependent H3K18Ac deacetylase, functions at chromatin to suppress ER stress and prevent the development of fatty liver disease. SIRT7 is induced upon ER stress and is stabilized at the promoters of ribosomal proteins through its interaction with the transcription factor Myc to silence gene expression and to relieve ER stress. SIRT7-deficient mice develop chronic hepatosteatosis resembling human fatty liver disease. Myc inactivation or pharmacological suppression of ER stress alleviates fatty liver caused by SIRT7 deficiency. Importantly, SIRT7 suppresses ER stress and reverts the fatty liver disease in diet-induced obese mice. Our study identifies SIRT7 as a cofactor of Myc for transcriptional repression and delineates a druggable regulatory branch of the ER stress response that prevents and reverts fatty liver disease.
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Affiliation(s)
- Jiyung Shin
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
| | - Ming He
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA.,Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yufei Liu
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Silvana Paredes
- Department of Medicine, Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305, USA.,Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Lidia Villanova
- Department of Medicine, Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305, USA.,Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA.,Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Katharine Brown
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
| | - Xiaolei Qiu
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
| | - Noushin Nabavi
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
| | - Mary Mohrin
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
| | - Kathleen Wojnoonski
- Department of Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Patrick Li
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA
| | - Hwei-Ling Cheng
- Howard Hughes Medical Institute, The Children's Hospital, CBR Institute for Biomedical Research, Harvard University Medical School, Boston, MA 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew J Murphy
- Regeneron Pharmaceuticals, Inc., 777 Old Saw Mill River Road, Tarrytown, NY 10591, USA
| | - David M Valenzuela
- Regeneron Pharmaceuticals, Inc., 777 Old Saw Mill River Road, Tarrytown, NY 10591, USA
| | - Hanzhi Luo
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
| | - Pankaj Kapahi
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA
| | - Ronald Krauss
- Department of Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Raul Mostoslavsky
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - George D Yancopoulos
- Regeneron Pharmaceuticals, Inc., 777 Old Saw Mill River Road, Tarrytown, NY 10591, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute, The Children's Hospital, CBR Institute for Biomedical Research, Harvard University Medical School, Boston, MA 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Katrin F Chua
- Department of Medicine, Division of Endocrinology, Gerontology, and Metabolism, Stanford University School of Medicine, Stanford, CA 94305, USA.,Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Danica Chen
- Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, USA
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497
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Wiita AP, Ziv E, Wiita PJ, Urisman A, Julien O, Burlingame AL, Weissman JS, Wells JA. Global cellular response to chemotherapy-induced apoptosis. eLife 2013; 2:e01236. [PMID: 24171104 PMCID: PMC3808542 DOI: 10.7554/elife.01236] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/23/2013] [Indexed: 12/28/2022] Open
Abstract
How cancer cells globally struggle with a chemotherapeutic insult before succumbing to apoptosis is largely unknown. Here we use an integrated systems-level examination of transcription, translation, and proteolysis to understand these events central to cancer treatment. As a model we study myeloma cells exposed to the proteasome inhibitor bortezomib, a first-line therapy. Despite robust transcriptional changes, unbiased quantitative proteomics detects production of only a few critical anti-apoptotic proteins against a background of general translation inhibition. Simultaneous ribosome profiling further reveals potential translational regulation of stress response genes. Once the apoptotic machinery is engaged, degradation by caspases is largely independent of upstream bortezomib effects. Moreover, previously uncharacterized non-caspase proteolytic events also participate in cellular deconstruction. Our systems-level data also support co-targeting the anti-apoptotic regulator HSF1 to promote cell death by bortezomib. This integrated approach offers unique, in-depth insight into apoptotic dynamics that may prove important to preclinical evaluation of any anti-cancer compound. DOI:http://dx.doi.org/10.7554/eLife.01236.001 Many cancer treatments work by causing cancer cells to enter an advanced stage of a process known as programmed cell death or apoptosis. When a cell begins apoptosis, it takes a series of metabolic steps–such as fragmenting its DNA or reducing its volume–that eventually kills it. The cancer cells in tumours are able to grow because they are able to avoid apoptosis. When cancer cells are treated with cytotoxic drugs they do not die immediately but try to stave off the effect of the drug. However, we still know relatively little about what happens at the molecular levels as cancer cells struggle to avoid apoptosis. Now Wiita et al. have combined two methods for studying cancer cells–deep sequencing of RNA and quantitative proteomics–to simultaneously observe a variety of processes, including the transcription of genes to produce messenger RNA (mRNA) molecules, the translation of these mRNA molecules to produce proteins, and the proteolysis (or breakdown) of these proteins when the cells were subjected to chemotherapy. Wiita et al. studied how human myeloma cells responded to bortezomib, a drug that is used to treat various blood cancers, and found that ribosomes–the complex molecular machines that perform the translation step– reacted to the chemotherapy by preferentially translating certain mRNA molecules in order to produce a set of proteins that protect the cell. Developing drugs to inhibit the effects of these stress-response proteins could make the cancer cells more responsive to existing anticancer drugs. When this effort to stay alive is ultimately unsuccessful, the destruction of proteins appears surprisingly unrelated to the previous attempts that were made to protect the cell. With further work the “global cellular response” approach developed by Wiita et al. could lead to the discovery of new drug targets, improve our understanding of drug resistance in chemotherapy, and provide new ways to monitor how patients respond to treatment. DOI:http://dx.doi.org/10.7554/eLife.01236.002
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Affiliation(s)
- Arun P Wiita
- Department of Pharmaceutical Chemistry , University of California, San Francisco , San Francisco , United States ; Department of Laboratory Medicine , University of California, San Francisco , San Francisco , United States
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498
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Reinhardt S, Schuck F, Grösgen S, Riemenschneider M, Hartmann T, Postina R, Grimm M, Endres K. Unfolded protein response signaling by transcription factor XBP-1 regulates ADAM10 and is affected in Alzheimer's disease. FASEB J 2013; 28:978-97. [PMID: 24165480 DOI: 10.1096/fj.13-234864] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In Alzheimer's disease (AD), disturbed homeostasis of the proteases competing for amyloid precursor protein processing has been reported: a disintegrin and metalloproteinase 10 (ADAM10), the physiological α-secretase, is decreased in favor of the amyloid-β-generating enzyme BACE-1. To identify transcription factors that modulate the expression of either protease, we performed a screening approach: 48 transcription factors significantly interfered with ADAM10/BACE-1-promoter activity. One selective inducer of ADAM10 gene expression is the X-box binding protein-1 (XBP-1). This protein regulates the unfolded protein-response pathway. We demonstrate that particularly the spliced XBP-1 variant dose dependently regulates ADAM10 expression, which can be synergistically enhanced by 100 nM insulin. Analysis of 2 different transgenic mouse models (APP/PS1 and 5xFAD) revealed that at early time points in pathology XBP-1 metabolism is induced. This is accompanied by a 2-fold augmented ADAM10 amount as compared with nontransgenic littermates (P=0.011). Along with aging of the mice, the system is counterregulated, and XBP-1 together with ADAM10 expression level decreased to ∼50% as compared with control animals. Analyses of expression levels in human AD brains showed that ADAM10 mRNA correlated with active XBP-1 (r=0.3120), but expression did not reach levels of healthy age-matched controls, suggesting deregulation of XBP-1 signaling. Our results demonstrate that XBP-1 is a driver of ADAM10 gene expression and that disturbance of this pathway might contribute to development or progression of AD.
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Affiliation(s)
- Sven Reinhardt
- 1Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Untere Zahlbacher Strasse 8, 55131 Mainz, Germany.
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Lake AD, Novak P, Hardwick RN, Flores-Keown B, Zhao F, Klimecki WT, Cherrington NJ. The adaptive endoplasmic reticulum stress response to lipotoxicity in progressive human nonalcoholic fatty liver disease. Toxicol Sci 2013; 137:26-35. [PMID: 24097666 DOI: 10.1093/toxsci/kft230] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) may progress from simple steatosis to severe, nonalcoholic steatohepatitis (NASH) in 7%-14% of the U.S. population through a second "hit" in the form of increased oxidative stress and inflammation. Endoplasmic reticulum (ER) stress signaling and the unfolded protein response (UPR) are triggered when high levels of lipids and misfolded proteins alter ER homeostasis creating a lipotoxic environment within NAFLD livers. The objective of this study was to determine the coordinate regulation of ER stress-associated genes in the progressive stages of human NAFLD. Human liver samples categorized as normal, steatosis, NASH (Fatty), and NASH (Not Fatty) were analyzed by individual Affymetrix GeneChip Human 1.0 ST microarrays, immunoblots, and immunohistochemistry. A gene set enrichment analysis was performed on autophagy, apoptosis, lipogenesis, and ER stress/UPR gene categories. An enrichment of downregulated genes in the ER stress-associated lipogenesis and ER stress/UPR gene categories was observed in NASH. Conversely, an enrichment of upregulated ER stress-associated genes for autophagy and apoptosis gene categories was observed in NASH. Protein expression of the adaptive liver response protein STC2 and the transcription factor X-box binding protein 1 spliced (XBP-1s) were significantly elevated among NASH samples, whereas other downstream ER stress proteins including CHOP, ATF4, and phosphorylated JNK and eIF2α were not significantly changed in disease progression. Increased nuclear accumulation of total XBP-1 protein was observed in steatosis and NASH livers. The findings reveal the presence of a coordinated, adaptive transcriptional response to hepatic ER stress in human NAFLD.
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500
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Tomaszek A, Kiczak L, Bania J, Krupa P, Pasławska U, Zacharski M, Janiszewski A, Stefaniak T, Zyśko D, Ardehali H, Jankowska EA, Ponikowski P. Changes in parasympathetic system in medulla oblongata in male pigs in the course of tachycardia-induced cardiomyopathy. Auton Neurosci 2013; 177:253-9. [DOI: 10.1016/j.autneu.2013.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 04/30/2013] [Accepted: 05/20/2013] [Indexed: 01/14/2023]
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