1
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Liang W, Fu L, Feng M, Wang X, Yun Z, Xu J. Endoplasmic Reticulum Stress and Autophagy Are Involved in Hepatotoxicity Induced by Tributyltin. TOXICS 2023; 11:607. [PMID: 37505572 PMCID: PMC10386594 DOI: 10.3390/toxics11070607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/29/2023]
Abstract
Tributyltin (TBT), a common contaminant in aquatic ecosystems, has severe toxic effects on multiple tissues and organs, especially the liver. Previous toxicogenomic analysis has indicated that the main mechanism of TBT-induced hepatotoxicity is related to the activation of the apoptotic pathway. However, the mechanism of action occurring before the activation of apoptosis is still unclear. Herein, we applied proteomic technology to explore the protein expression profile of TBT-treated HL7702 normal human liver cells. The ultrastructural changes in cells were observed by transmission electron microscopy. After low dose (2 μΜ) TBT treatment, activation of the unfolded protein response and endoplasmic reticulum stress were observed; the expression levels of PERK, ATF6, BiP, and CHOP were significantly elevated, and splicing of XBP1 mRNA was initiated. When the TBT concentration increased to 4 μΜ, the protein levels of Beclin1, Atg3, Atg5, Atg7, and Atg12-Atg5 were significantly elevated, and the protein level of LC3Ⅰ decreased while that of LC3Ⅱ increased, suggesting the activation of autophagy. As the TBT concentration continued to increase, autophagy could not eliminate the damage, and apoptosis eventually occurred. These results indicate novel pathways of hepatotoxicity induced by TBT and provide insights for future studies.
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Affiliation(s)
- Weiqi Liang
- School of Public Health, Health Science Center, Ningbo University, Ningbo 315211, China
| | - Lingling Fu
- School of Public Health, Health Science Center, Ningbo University, Ningbo 315211, China
| | - Mei Feng
- School of Public Health, Health Science Center, Ningbo University, Ningbo 315211, China
| | - Xiaorong Wang
- School of Public Health, Health Science Center, Ningbo University, Ningbo 315211, China
| | - Zhaohui Yun
- School of Public Health, Health Science Center, Ningbo University, Ningbo 315211, China
| | - Jin Xu
- School of Public Health, Health Science Center, Ningbo University, Ningbo 315211, China
- Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo 315211, China
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2
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Hrach VL, King WR, Nelson LD, Conklin S, Pollock JA, Patton-Vogt J. The acyltransferase Gpc1 is both a target and an effector of the unfolded protein response in Saccharomyces cerevisiae. J Biol Chem 2023; 299:104884. [PMID: 37269946 PMCID: PMC10331479 DOI: 10.1016/j.jbc.2023.104884] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 05/25/2023] [Accepted: 05/27/2023] [Indexed: 06/05/2023] Open
Abstract
The unfolded protein response (UPR) is sensitive to proteotoxic and membrane bilayer stress, both of which are sensed by the ER protein Ire1. When activated, Ire1 splices HAC1 mRNA, producing a transcription factor that targets genes involved in proteostasis and lipid metabolism, among others. The major membrane lipid phosphatidylcholine (PC) is subject to phospholipase-mediated deacylation, producing glycerophosphocholine (GPC), followed by reacylation of GPC through the PC deacylation/reacylation pathway (PC-DRP). The reacylation events occur via a two-step process catalyzed first by the GPC acyltransferase Gpc1, followed by acylation of the lyso-PC molecule by Ale1. However, whether Gpc1 is critical for ER bilayer homeostasis is unclear. Using an improved method for C14-choline-GPC radiolabeling, we first show that loss of Gpc1 results in abrogation of PC synthesis through PC-DRP and that Gpc1 colocalizes with the ER. We then probe the role of Gpc1 as both a target and an effector of the UPR. Exposure to the UPR-inducing compounds tunicamycin, DTT, and canavanine results in a Hac1-dependent increase in GPC1 message. Further, cells lacking Gpc1 exhibit increased sensitivity to those proteotoxic stressors. Inositol limitation, known to induce the UPR via bilayer stress, also induces GPC1 expression. Finally, we show that loss of GPC1 induces the UPR. A gpc1Δ mutant displays upregulation of the UPR in strains expressing a mutant form of Ire1 that is unresponsive to unfolded proteins, indicating that bilayer stress is responsible for the observed upregulation. Collectively, our data indicate an important role for Gpc1 in yeast ER bilayer homeostasis.
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Affiliation(s)
- Victoria Lee Hrach
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - William R King
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Laura D Nelson
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Shane Conklin
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - John A Pollock
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.
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3
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Miyahara H, Hasegawa K, Yashiro M, Ohara T, Fujisawa M, Yoshimura T, Matsukawa A, Tsukahara H. Thioredoxin interacting protein protects mice from fasting induced liver steatosis by activating ER stress and its downstream signaling pathways. Sci Rep 2022; 12:4819. [PMID: 35314758 PMCID: PMC8938456 DOI: 10.1038/s41598-022-08791-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
Under normal conditions, fasting results in decreased protein disulfide isomerase (PDI) activity and accumulation of unfolded proteins, leading to the subsequent activation of the unfolded protein response (UPR)/autophagy signaling pathway to eliminate damaged mitochondria. Fasting also induces upregulation of thioredoxin-interacting protein (TXNIP) expression and mice deficient of this protein (TXNIP-KO mice) was shown to develop severe hypoglycemia, hyperlipidemia and liver steatosis (LS). In the present study, we aimed to determine the role of TXNIP in fasting-induced LS by using male TXNIP-KO mice that developed LS without severe hypoglycemia. In TXNIP-KO mice, fasting induced severe microvesicular LS. Examinations by transmission electron microscopy revealed mitochondria with smaller size and deformities and the presence of few autophagosomes. The expression of β-oxidation-associated genes remained at the same level and the level of LC3-II was low. PDI activity level stayed at the original level and the levels of p-IRE1 and X-box binding protein 1 spliced form (sXBP1) were lower. Interestingly, treatment of TXNIP-KO mice with bacitracin, a PDI inhibitor, restored the level of LC3-II after fasting. These results suggest that TXNIP regulates PDI activity and subsequent activation of the UPR/autophagy pathway and plays a protective role in fasting-induced LS.
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Affiliation(s)
- Hiroyuki Miyahara
- Department of Pediatrics, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. .,Department of Pediatrics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| | - Kosei Hasegawa
- Department of Pediatrics, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Masato Yashiro
- Department of Pediatrics, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Toshiaki Ohara
- Department of Pathology and Experimental Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Masayoshi Fujisawa
- Department of Pathology and Experimental Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Teizo Yoshimura
- Department of Pathology and Experimental Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Akihiro Matsukawa
- Department of Pathology and Experimental Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hirokazu Tsukahara
- Department of Pediatrics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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4
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Brown M, Dainty S, Strudwick N, Mihai AD, Watson JN, Dendooven R, Paton AW, Paton JC, Schröder M. Endoplasmic reticulum stress causes insulin resistance by inhibiting delivery of newly synthesized insulin receptors to the cell surface. Mol Biol Cell 2020; 31:2597-2629. [PMID: 32877278 PMCID: PMC7851869 DOI: 10.1091/mbc.e18-01-0013] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 08/21/2020] [Accepted: 08/28/2020] [Indexed: 12/20/2022] Open
Abstract
Accumulation of unfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates a signaling network known as the unfolded protein response (UPR). Here we characterize how ER stress and the UPR inhibit insulin signaling. We find that ER stress inhibits insulin signaling by depleting the cell surface population of the insulin receptor. ER stress inhibits proteolytic maturation of insulin proreceptors by interfering with transport of newly synthesized insulin proreceptors from the ER to the plasma membrane. Activation of AKT, a major target of the insulin signaling pathway, by a cytosolic, membrane-bound chimera between the AP20187-inducible FV2E dimerization domain and the cytosolic protein tyrosine kinase domain of the insulin receptor was not affected by ER stress. Hence, signaling events in the UPR, such as activation of the JNK mitogen-activated protein (MAP) kinases or the pseudokinase TRB3 by the ER stress sensors IRE1α and PERK, do not contribute to inhibition of signal transduction in the insulin signaling pathway. Indeed, pharmacologic inhibition and genetic ablation of JNKs, as well as silencing of expression of TRB3, did not restore insulin sensitivity or rescue processing of newly synthesized insulin receptors in ER-stressed cells. [Media: see text].
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Affiliation(s)
- Max Brown
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
| | - Samantha Dainty
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
| | - Natalie Strudwick
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
| | - Adina D. Mihai
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
| | - Jamie N. Watson
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
| | - Robina Dendooven
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
| | - Adrienne W. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
| | - Martin Schröder
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom
- North East England Stem Cell Institute (NESCI), Newcastle Upon Tyne NE1 4EP, United Kingdom
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5
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Xia X. Translation Control of HAC1 by Regulation of Splicing in Saccharomyces cerevisiae. Int J Mol Sci 2019; 20:ijms20122860. [PMID: 31212749 PMCID: PMC6627864 DOI: 10.3390/ijms20122860] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/30/2019] [Accepted: 06/10/2019] [Indexed: 12/19/2022] Open
Abstract
Hac1p is a key transcription factor regulating the unfolded protein response (UPR) induced by abnormal accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) in Saccharomyces cerevisiae. The accumulation of unfolded/misfolded proteins is sensed by protein Ire1p, which then undergoes trans-autophosphorylation and oligomerization into discrete foci on the ER membrane. HAC1 pre-mRNA, which is exported to the cytoplasm but is blocked from translation by its intron sequence looping back to its 5’UTR to form base-pair interaction, is transported to the Ire1p foci to be spliced, guided by a cis-acting bipartite element at its 3’UTR (3’BE). Spliced HAC1 mRNA can be efficiently translated. The resulting Hac1p enters the nucleus and activates, together with coactivators, a large number of genes encoding proteins such as protein chaperones to restore and maintain ER homeostasis and secretary protein quality control. This review details the translation regulation of Hac1p production, mediated by the nonconventional splicing, in the broad context of translation control and summarizes the evolution and diversification of the UPR signaling pathway among fungal, metazoan and plant lineages.
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Affiliation(s)
- Xuhua Xia
- Department of Biology, University of Ottawa, Marie-Curie Private, Ottawa, ON K1N 9A7, Canada.
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6
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Comparative Genomic Screen in Two Yeasts Reveals Conserved Pathways in the Response Network to Phenol Stress. G3-GENES GENOMES GENETICS 2019; 9:639-650. [PMID: 30647105 PMCID: PMC6404616 DOI: 10.1534/g3.118.201000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Living organisms encounter various perturbations, and response mechanisms to such perturbations are vital for species survival. Defective stress responses are implicated in many human diseases including cancer and neurodegenerative disorders. Phenol derivatives, naturally occurring and synthetic, display beneficial as well as detrimental effects. The phenol derivatives in this study, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and bisphenol A (BPA), are widely used as food preservatives and industrial chemicals. Conflicting results have been reported regarding their biological activity and correlation with disease development; understanding the molecular basis of phenol action is a key step for addressing issues relevant to human health. This work presents the first comparative genomic analysis of the genetic networks for phenol stress response in an evolutionary context of two divergent yeasts, Schizosaccharomyces pombe and Saccharomyces cerevisiae. Genomic screening of deletion strain libraries of the two yeasts identified genes required for cellular response to phenol stress, which are enriched in human orthologs. Functional analysis of these genes uncovered the major signaling pathways involved. The results provide a global view of the biological events constituting the defense process, including cell cycle arrest, DNA repair, phenol detoxification by V-ATPases, reactive oxygen species alleviation, and endoplasmic reticulum stress relief through ergosterol and the unfolded protein response, revealing novel roles for these cellular pathways.
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7
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Stone S, Wu S, Jamison S, Durose W, Pallais JP, Lin W. Activating transcription factor 6α deficiency exacerbates oligodendrocyte death and myelin damage in immune-mediated demyelinating diseases. Glia 2018; 66:1331-1345. [PMID: 29436030 DOI: 10.1002/glia.23307] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/16/2018] [Accepted: 01/29/2018] [Indexed: 01/06/2023]
Abstract
Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) play a critical role in immune-mediated demyelinating diseases, including multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), by regulating the viability of oligodendrocytes. Our previous studies show that activation of the PERK branch of the UPR protects myelinating oligodendrocytes against ER stress in young, developing mice that express IFN-γ, a key pro-inflammatory cytokine in MS and EAE, in the CNS. Several studies also demonstrate that PERK activation preserves oligodendrocyte viability and function, protecting mice against EAE. While evidence suggests activation of the ATF6α branch of the UPR in oligodendrocytes under normal and disease conditions, the effects of ATF6α activation on oligodendrocytes in immune-mediated demyelinating diseases remain unknown. Herein, we showed that ATF6α deficiency had no effect on oligodendrocytes under normal conditions. Interestingly, we showed that ATF6α deficiency exacerbated ER stressed-induced myelinating oligodendrocyte death and subsequent myelin loss in the developing CNS of IFN-γ-expressing mice. Moreover, we found that ATF6α deficiency increased EAE severity and aggravated EAE-induced oligodendrocyte loss and demyelination, without affecting inflammation. Thus, these data suggest the protective effects of ATF6α activation on oligodendrocytes in immune-mediated demyelinating diseases.
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Affiliation(s)
- Sarrabeth Stone
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Shuangchan Wu
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Stephanie Jamison
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Wilaiwan Durose
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Jean Pierre Pallais
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
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8
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Jonas FRH, Royle KE, Aw R, Stan GBV, Polizzi KM. Investigating the consequences of asymmetric endoplasmic reticulum inheritance in Saccharomyces cerevisiae under stress using a combination of single cell measurements and mathematical modelling. Synth Syst Biotechnol 2018; 3:64-75. [PMID: 29911200 PMCID: PMC5884231 DOI: 10.1016/j.synbio.2018.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/29/2017] [Accepted: 01/05/2018] [Indexed: 11/23/2022] Open
Abstract
Adaptation allows organisms to maintain a constant internal environment, which is optimised for growth. The unfolded protein response (UPR) is an example of a feedback loop that maintains endoplasmic reticulum (ER) homeostasis, and is characteristic of how adaptation is often mediated by transcriptional networks. The more recent discovery of asymmetric division in maintaining ER homeostasis, however, is an example of how alternative non-transcriptional pathways can exist, but are overlooked by gold standard transcriptomic or proteomic population-based assays. In this study, we have used a combination of fluorescent reporters, flow cytometry and mathematical modelling to explore the relative roles of asymmetric cell division and the UPR in maintaining ER homeostasis. Under low ER stress, asymmetric division leaves daughter cells with an ER deficiency, necessitating activation of the UPR and prolonged cell cycle during which they can recover ER functionality before growth. Mathematical analysis of and simulation results from our mathematical model reinforce the experimental observations that low ER stress primarily impacts the growth rate of the daughter cells. These results demonstrate the interplay between homeostatic pathways and the importance of exploring sub-population dynamics to understand population adaptation to quantitatively different stresses.
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Affiliation(s)
- Felix R H Jonas
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, United Kingdom.,Imperial College Centre for Synthetic Biology, London, SW7 2AZ, United Kingdom
| | - Kate E Royle
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, United Kingdom.,Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Rochelle Aw
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, United Kingdom.,Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Guy-Bart V Stan
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, United Kingdom.,Imperial College Centre for Synthetic Biology, London, SW7 2AZ, United Kingdom
| | - Karen M Polizzi
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, United Kingdom.,Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
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9
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Duran-Bedolla J, Téllez-Sosa J, Valdovinos-Torres H, Pavón N, Buelna-Chontal M, Tello-López AT, Argotte-Ramos R, Rodríguez MH, Rodríguez MC. Cellular stress associated with the differentiation of Plasmodium berghei ookinetes. Biochem Cell Biol 2016; 95:310-317. [PMID: 28177775 DOI: 10.1139/bcb-2016-0028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
For malaria transmission, Plasmodium parasites must develop in the mosquito vector. Oxidative stress in the insect midgut, triggered by environmental changes (e.g., pH and temperature), influences the cellular signaling involved in differentiation from gametocytes to mobile ookinetes for the purpose of parasite survival. Oxidative stress activates the homeostatic response to stress characterized by the phosphorylation eIF2α, the attenuation of protein synthesis, and the transcription of genes participating in the unfolded protein response and antioxidant processes, forming a part of an integrated stress response (ISR). We hypothesized that ISR operates during the differentiation of gametocytes to ookinetes to assure Plasmodium survival. Using in-vitro conditions resembling the mosquito midgut conditions, we cultured Plasmodium berghei gametocytes to ookinetes and evaluated the redox balance by detecting reactive oxygen species and superoxide dismutase activity. Additionally, we evaluated the phosphorylation of eIF2α, the attenuation of the global protein synthesis, and the gene expression of cellular stress markers (e.g., endoplasmic reticulum chaperones and antioxidant molecules, measured by reverse-transcription quantitative polymerase chain reaction), finding that these processes were all taking place, probably to improve survival during the differentiation of Plasmodium berghei ookinetes.
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Affiliation(s)
- Josefina Duran-Bedolla
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
| | - Juan Téllez-Sosa
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
| | - Humberto Valdovinos-Torres
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
| | - Natalia Pavón
- b Departamento de Farmacología and Departamento de Biomedicina Cardiovascular, Instituto Nacional de Cardiología, Ignacio Chávez, Juan Badiano # 1, Col. Sección XVI, C.P. 014080, Tlalpan, D.F., México
| | - Mabel Buelna-Chontal
- b Departamento de Farmacología and Departamento de Biomedicina Cardiovascular, Instituto Nacional de Cardiología, Ignacio Chávez, Juan Badiano # 1, Col. Sección XVI, C.P. 014080, Tlalpan, D.F., México
| | - Angel T Tello-López
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
| | - Rocio Argotte-Ramos
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
| | - Mario Henry Rodríguez
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
| | - María Carmen Rodríguez
- a Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad 655, C.P. 62100, Cuernavaca, Morelos, México
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10
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Brown M, Strudwick N, Suwara M, Sutcliffe LK, Mihai AD, Ali AA, Watson JN, Schröder M. An initial phase of JNK activation inhibits cell death early in the endoplasmic reticulum stress response. J Cell Sci 2016; 129:2317-2328. [PMID: 27122189 DOI: 10.1242/jcs.179127] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 04/20/2016] [Indexed: 12/21/2022] Open
Abstract
Accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates the unfolded protein response (UPR). In mammalian cells, UPR signals generated by several ER-membrane-resident proteins, including the bifunctional protein kinase endoribonuclease IRE1α, control cell survival and the decision to execute apoptosis. Processing of XBP1 mRNA by the RNase domain of IRE1α promotes survival of ER stress, whereas activation of the mitogen-activated protein kinase JNK family by IRE1α late in the ER stress response promotes apoptosis. Here, we show that activation of JNK in the ER stress response precedes activation of XBP1. This activation of JNK is dependent on IRE1α and TRAF2 and coincides with JNK-dependent induction of expression of several antiapoptotic genes, including cIap1 (also known as Birc2), cIap2 (also known as Birc3), Xiap and Birc6 ER-stressed Jnk1(-/-) Jnk2(-/-) (Mapk8(-/-) Mapk9(-/-)) mouse embryonic fibroblasts (MEFs) display more pronounced mitochondrial permeability transition and increased caspase 3/7 activity compared to wild-type MEFs. Caspase 3/7 activity is also elevated in ER-stressed cIap1(-/-) cIap2(-/-) and Xiap(-/-) MEFs. These observations suggest that JNK-dependent transcriptional induction of several inhibitors of apoptosis contributes to inhibiting apoptosis early in the ER stress response.
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Affiliation(s)
- Max Brown
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
| | - Natalie Strudwick
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
| | - Monika Suwara
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
| | - Louise K Sutcliffe
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
| | - Adina D Mihai
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
| | - Ahmed A Ali
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK.,Molecular Biology Department, National Research Centre, Dokki 12311, Cairo, Egypt
| | - Jamie N Watson
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
| | - Martin Schröder
- Durham University, School of Biological and Biomedical Sciences, Durham DH1 3LE, United Kingdom.,Biophysical Sciences Institute, Durham University, Durham DH1 3LE, United Kingdom.,North East England Stem Cell Institute (NESCI), Life Bioscience Centre, International Centre for Life, Central Parkway, Newcastle Upon Tyne, NE1 4EP, UK
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11
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Liu CL, Li X, Gan L, He YY, Wang LL, He KL. High-content screening identifies inhibitors of the nuclear translocation of ATF6. Int J Mol Med 2015; 37:407-14. [PMID: 26707144 DOI: 10.3892/ijmm.2015.2442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/11/2015] [Indexed: 11/06/2022] Open
Abstract
Activating transcription factor 6 (ATF6) is a transmembrane protein that consists of a cytoplasmic domain and an endoplasmic reticulum (ER) luminal domain. As unfolded protein levels arise in the ER, the ER cytoplasmic domain of ATF6 moves to the nucleus, where it activates the transcription of a range of genes, including those involved in apoptosis. As ATF6 only becomes functional once it has moved to the nucleus, compounds that inhibit its re-localization are of therapeutic interest. The aim of the present study was to rapidly and accurately identify such compounds using a novel image‑based, high‑content screening (HCS) technique. The results from the HCS analysis were then confirmed by luciferase reporter assays, western blot analysis and the measurement of cell viability. We found that HCS identified compounds which inhibited ATF6 nuclear translocation with high specificity, as confirmed by the luciferase reporter assay and western blot analysis. Moreover, we demonstrated that 3 of the 80 identified compounds impaired ATF6-mediated induced cell death. The data from this study support the theory that HCS is a novel, high throughput method which can be used for accurate and rapid compound screening.
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Affiliation(s)
- Chun-Lei Liu
- Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Xin Li
- Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Lu Gan
- Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Yun-Yun He
- Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Li-Li Wang
- Pharmacy Institute of Military Medical Sciences, Beijing 100850, P.R. China
| | - Kun-Lun He
- Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, P.R. China
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12
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Stone S, Lin W. The unfolded protein response in multiple sclerosis. Front Neurosci 2015; 9:264. [PMID: 26283904 PMCID: PMC4518158 DOI: 10.3389/fnins.2015.00264] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/14/2015] [Indexed: 01/08/2023] Open
Abstract
The unfolded protein response (UPR) occurs in response to endoplasmic reticulum (ER) stress caused by the accumulation of unfolded or misfolded proteins in the ER. The UPR is comprised of three signaling pathways that promote cytoprotective functions to correct ER stress; however, if ER stress cannot be resolved the UPR results in apoptosis of affected cells. The UPR is an important feature of various human diseases, including multiple sclerosis (MS). Recent studies have shown several components of the UPR are upregulated in the multiple cell types in MS lesions, including oligodendrocytes, T cells, microglia/macrophages, and astrocytes. Data from animal model studies, particularly studies of experimental autoimmune encephalomyelitis (EAE) and the cuprizone model, imply an important role of the UPR activation in oligodendrocytes in the development of MS. In this review we will cover current literature on the UPR and the evidence for its role in the development of MS.
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Affiliation(s)
- Sarrabeth Stone
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA ; Institute for Translational Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA ; Institute for Translational Neuroscience, University of Minnesota Minneapolis, MN, USA
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13
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Mihai AD, Schröder M. Glucose starvation and hypoxia, but not the saturated fatty acid palmitic acid or cholesterol, activate the unfolded protein response in 3T3-F442A and 3T3-L1 adipocytes. Adipocyte 2015; 4:188-202. [PMID: 26257992 DOI: 10.4161/21623945.2014.989728] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 11/08/2014] [Accepted: 11/14/2014] [Indexed: 12/26/2022] Open
Abstract
Obesity is associated with endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) in adipose tissue. In this study we identify physiological triggers of ER stress and of the UPR in adipocytes in vitro. We show that two markers of adipose tissue remodelling in obesity, glucose starvation and hypoxia, cause ER stress in 3T3-F442A and 3T3-L1 adipocytes. Both conditions induced molecular markers of the IRE1α and PERK branches of the UPR, such as splicing of XBP1 mRNA and CHOP, as well as transcription of the ER stress responsive gene BiP. Hypoxia also induced an increase in phosphorylation of the PERK substrate eIF2α. By contrast, physiological triggers of ER stress in many other cell types, such as the saturated fatty acid palmitic acid, cholesterol, or several inflammatory cytokines including TNF-α, IL-1β, and IL-6, do not cause ER stress in 3T3-F442A and 3T3-L1 adipocytes. Our data suggest that physiological changes associated with remodelling of adipose tissue in obesity, such as hypoxia and glucose starvation, are more likely physiological ER stressors of adipocytes than the lipid overload or hyperinsulinemia associated with obesity.
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14
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Dunlap KM, Bartee MY, Bartee E. Myxoma virus attenuates expression of activating transcription factor 4 (ATF4) which has implications for the treatment of proteasome inhibitor-resistant multiple myeloma. Oncolytic Virother 2015; 4:1-11. [PMID: 27512665 PMCID: PMC4918372 DOI: 10.2147/ov.s72372] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The recent development of chemotherapeutic proteasome inhibitors, such as bortezomib, has improved the outcomes of patients suffering from the plasma cell malignancy multiple myeloma. Unfortunately, many patients treated with these drugs still suffer relapsing disease due to treatment-induced upregulation of the antiapoptotic protein Mcl1. We have recently demonstrated that an oncolytic poxvirus, known as myxoma, can rapidly eliminate primary myeloma cells by inducing cellular apoptosis. The efficacy of myxoma treatment on proteasome inhibitor–relapsed or –refractory myeloma, however, remains unknown. We now demonstrate that myxoma-based elimination of myeloma is not affected by cellular resistance to proteasome inhibitors. Additionally, myxoma virus infection specifically prevents expression of Mcl1 following induction of the unfolded protein response, by blocking translation of the unfolded protein response activating transcription factor (ATF)4. These results suggest that myxoma-based oncolytic therapy represents an attractive option for myeloma patients whose disease is refractory to chemotherapeutic proteasome inhibitors due to upregulation of Mcl1.
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Affiliation(s)
- Katherine M Dunlap
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Mee Y Bartee
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Eric Bartee
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
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15
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Evstafieva AG, Garaeva AA, Khutornenko AA, Klepikova AV, Logacheva MD, Penin AA, Novakovsky GE, Kovaleva IE, Chumakov PM. A sustained deficiency of mitochondrial respiratory complex III induces an apoptotic cell death through the p53-mediated inhibition of pro-survival activities of the activating transcription factor 4. Cell Death Dis 2014; 5:e1511. [PMID: 25375376 PMCID: PMC4260727 DOI: 10.1038/cddis.2014.469] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/11/2014] [Accepted: 09/24/2014] [Indexed: 11/09/2022]
Abstract
Generation of energy in mitochondria is subjected to physiological regulation at many levels, and its malfunction may result in mitochondrial diseases. Mitochondrial dysfunction is associated with different environmental influences or certain genetic conditions, and can be artificially induced by inhibitors acting at different steps of the mitochondrial electron transport chain (ETC). We found that a short-term (5 h) inhibition of ETC complex III with myxothiazol results in the phosphorylation of translation initiation factor eIF2α and upregulation of mRNA for the activating transcription factor 4 (ATF4) and several ATF4-regulated genes. The changes are characteristic for the adaptive integrated stress response (ISR), which is known to be triggered by unfolded proteins, nutrient and metabolic deficiency, and mitochondrial dysfunctions. However, after a prolonged incubation with myxothiazol (13-17 h), levels of ATF4 mRNA and ATF4-regulated transcripts were found substantially suppressed. The suppression was dependent on the p53 response, which is triggered by the impairment of the complex III-dependent de novo biosynthesis of pyrimidines by mitochondrial dihydroorotate dehydrogenase. The initial adaptive induction of ATF4/ISR acted to promote viability of cells by attenuating apoptosis. In contrast, the induction of p53 upon a sustained inhibition of ETC complex III produced a pro-apoptotic effect, which was additionally stimulated by the p53-mediated abrogation of the pro-survival activities of the ISR. Interestingly, a sustained inhibition of ETC complex I by piericidine did not induce the p53 response and stably maintained the pro-survival activation of ATF4/ISR. We conclude that a downregulation of mitochondrial ETC generally induces adaptive pro-survival responses, which are specifically abrogated by the suicidal p53 response triggered by the genetic risks of the pyrimidine nucleotide deficiency.
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Affiliation(s)
- A G Evstafieva
- 1] Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia [2] Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - A A Garaeva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - A A Khutornenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - A V Klepikova
- 1] Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia [2] Faculty of Biology, Department of Genetics, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - M D Logacheva
- 1] Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia [2] Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - A A Penin
- 1] Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia [2] Faculty of Biology, Department of Genetics, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - G E Novakovsky
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - I E Kovaleva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - P M Chumakov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova Street 32, Moscow, 119991, Russia
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16
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IRE1: ER stress sensor and cell fate executor. Trends Cell Biol 2013; 23:547-55. [PMID: 23880584 DOI: 10.1016/j.tcb.2013.06.005] [Citation(s) in RCA: 401] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/31/2013] [Accepted: 06/19/2013] [Indexed: 12/20/2022]
Abstract
Cells operate a signaling network termed the unfolded protein response (UPR) to monitor protein-folding capacity in the endoplasmic reticulum (ER). Inositol-requiring enzyme 1 (IRE1) is an ER transmembrane sensor that activates the UPR to maintain the ER and cellular function. Although mammalian IRE1 promotes cell survival, it can initiate apoptosis via decay of antiapoptotic miRNAs. Convergent and divergent IRE1 characteristics between plants and animals underscore its significance in cellular homeostasis. This review provides an updated scenario of the IRE1 signaling model, discusses emerging IRE1 sensing mechanisms, compares IRE1 features among species, and outlines exciting future directions in UPR research.
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17
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Paredes RM, Bollo M, Holstein D, Lechleiter JD. Luminal Ca2+ depletion during the unfolded protein response in Xenopus oocytes: cause and consequence. Cell Calcium 2013; 53:286-96. [PMID: 23415071 DOI: 10.1016/j.ceca.2013.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/15/2013] [Accepted: 01/18/2013] [Indexed: 01/22/2023]
Abstract
The endoplasmic reticulum (ER) is a Ca(2+) storing organelle that plays a critical role in the synthesis, folding and post-translational modifications of many proteins. The ER enters into a condition of stress when the load of newly synthesized proteins exceeds its folding and processing capacity. This activates a signal transduction pathway called the unfolded protein response (UPR) that attempts to restore homeostasis. The precise role of ER Ca(2+) in the initiation of the UPR has not been defined. Specifically, it has not been established whether ER Ca(2+) dysregulation is a cause or consequence of ER stress. Here, we report that partial depletion of ER Ca(2+) stores induces a significant induction of the UPR, and leads to the retention of a normally secreted protein Carboxypeptidase Y. Moreover, inhibition of protein glycosylation by tunicamycin rapidly induced an ER Ca(2+) leak into the cytosol. However, blockade of the translocon with emetine inhibited the tunicamycin-induced Ca(2+) release. Furthermore, emetine treatment blocked elF2α phosphorylation and reduced expression of the chaperone BiP. These findings suggest that Ca(2+) may be both a cause and a consequence of ER protein misfolding. Thus, it appears that ER Ca(2+) leak is a significant co-factor for the initiation of the UPR.
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Affiliation(s)
- R Madelaine Paredes
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX 78229-3900, USA
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18
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He D, Li J, Zhao J, Fei J, Zhang X. C/EBP homologous protein induces mesangial cell apoptosis under hyperglycemia. Mol Med Rep 2012; 7:445-8. [PMID: 23241730 DOI: 10.3892/mmr.2012.1234] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/07/2012] [Indexed: 11/06/2022] Open
Abstract
Diabetes mellitus is known to cause kidney impairment; however, the mechanism remains elusive. The aim of this study was to investigate the role of C/EBP homologous protein (CHOP), an important protein in endoplasmic reticulum stress‑mediated mesangial cell apoptosis in hyperglycemia. Mesangial cells were cultured in normal (control group) and high glucose medium (high glucose group). TUNEL staining was performed to assess apoptotic cells in the groups. The expression of CHOP and caspase‑3 was also assayed by immunohistochemistry and western blot analysis. Following 24 h culture in high glucose medium, TUNEL‑positive cells were observed to be significantly increased (P<0.01). The expression of CHOP and caspase‑3 in mesangial cells was also found to be significantly enhanced under high glucose conditions compared with the normal group (P<0.01). The results indicate that CHOP mediates apoptosis in mesangial cells under hyperglycemia and may play a role in the development of diabetic nephropathy.
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Affiliation(s)
- Daqiang He
- Department of Anatomy and Cell Biology, School of Medicine, Zhejiang University, Zhejiang 310058, P.R. China
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19
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Wang Z, Zhang C, Hong Z, Chen H, Chen W, Chen G. C/EBP homologous protein (CHOP) mediates neuronal apoptosis in rats with spinal cord injury. Exp Ther Med 2012; 5:107-111. [PMID: 23251250 PMCID: PMC3523958 DOI: 10.3892/etm.2012.745] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 09/18/2012] [Indexed: 12/15/2022] Open
Abstract
Spinal cord injury (SCI) is a severe health problem and the mechanism involved remains elusive. The aim of the present study was to elucidate the role of C/EBP homologous protein (CHOP), a prominent protein of the endoplasmic reticulum (ER) stress-mediated apoptosis in SCI. A total of 20 adult male Sprague-Dawley rats were divided into two groups at random, ten rats were subjected to a modified Allen's test (using a weight-drop device) to induce a SCI model and the remaining ten rats only had the corresponding vertebral lamina removed with no injury and served as the sham-operated group. Pathological changes in the spinal cord were observed 12 h after injury by hematoxylin and eosin staining and TUNEL staining was performed to visualize apoptotic cells. The expression of CHOP was also detected by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction. The results showed that a typical apoptotic morphology, namely the increased the number of TUNEL-positive cells in the injured spinal cord. The expression levels of CHOP in the rats with SCI were increased compared with the sham-operated rats (P<0.05). These results revealed that CHOP-mediated ER stress-induced apoptosis may be involved in SCI.
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Affiliation(s)
- Zhangfu Wang
- Department of Orthopedics, Taizhou Hospital of Zhejiang Province, Taizhou, Zhejiang 317000, P.R. China
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Prell T, Lautenschläger J, Witte OW, Carri MT, Grosskreutz J. The unfolded protein response in models of human mutant G93A amyotrophic lateral sclerosis. Eur J Neurosci 2012; 35:652-60. [DOI: 10.1111/j.1460-9568.2012.08008.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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