1
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Li H, Zhang G, Liu Y, Gao F, Ye X, Lin R, Wen M. Hypoxia-inducible factor 1α inhibits heat stress-induced pig intestinal epithelial cell apoptosis through eif2α/ATF4/CHOP signaling. Sci Total Environ 2024; 924:171649. [PMID: 38485018 DOI: 10.1016/j.scitotenv.2024.171649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/01/2024] [Accepted: 03/09/2024] [Indexed: 03/17/2024]
Abstract
Unstoppable global warming and increased frequency of extreme heat leads to human and animals easier to suffer from heat stress (HS), with gastrointestinal abnormalities as one of the initial clinical symptoms. HS induces intestinal mucosal damage owing to intestinal hypoxia and hyperthermia. Hypoxia-inducible factor 1α (HIF-1α) activates numerous genes to mediate cell hypoxic responses; however, its role in HS-treated intestinal mucosa is unknown. This work aimed to explore HIF-1α function and regulatory mechanisms in HS-treated pig intestines. We assigned 10 pigs to control and moderate HS groups. Physical signs, stress, and antioxidant levels were detected, and the intestines were harvested after 72 h of HS treatment to study histological changes and HIF-1α, heat shock protein 90 (HSP90), and prolyl-4-hydroxylase 2 (PHD-2) expression. In addition, porcine intestinal columnar epithelial cells (IPEC-J2) underwent HS treatment (42 °C, 5 % O2) to further explore the functions and regulatory mechanism of HIF-1α. The results of histological examination revealed HS caused intestinal villi damage and increased apoptotic epithelial cell; the expression of HIF-1α and HSP90 increased while PHD-2 showed and opposite trend. Transcriptome sequencing analysis revealed that HS activated HIF-1 signaling. To further explore the role of HIF-1α on HS induced IPEC-J2 apoptosis, the HIF-1α was interfered and overexpression respectively, and the result confirmed that HIF-1α could inhibited cell apoptosis under HS. Furthermore, HS-induced apoptosis depends on eukaryotic initiation factor 2 alpha (eif2α)/activating transcription factor 4 (ATF4)/CCAAT-enhancer-binding protein homologous protein (CHOP) pathway, and HIF-1α can inhibit this pathway to alleviate IPEC-J2 cell apoptosis. In conclusion, this study suggests that HS can promote intestinal epithelial cell apoptosis and cause pig intestinal mucosal barrier damage; the HIF-1α can alleviate cell apoptosis by inhibiting eif2α/ATF4/CHOP signaling. These results indicate that HIF-1α plays a protective role in HS, and offers a potential target for HS prevention and mitigation.
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Affiliation(s)
- Hui Li
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China; College of Animal Science, Guizhou University, Guiyang 550000, PR China.
| | - Gang Zhang
- College of Animal Science, Guizhou University, Guiyang 550000, PR China
| | - Yongqing Liu
- College of Animal Science, Guizhou University, Guiyang 550000, PR China
| | - Fan Gao
- College of Animal Science, Guizhou University, Guiyang 550000, PR China
| | - Xinyue Ye
- College of Agriculture, Guizhou University, Guiyang 550000, PR China
| | - Rutao Lin
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China; College of Animal Science, Guizhou University, Guiyang 550000, PR China.
| | - Ming Wen
- College of Animal Science, Guizhou University, Guiyang 550000, PR China.
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2
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Chang HH, Huang LC, Browning KS, Huq E, Cheng MC. The phosphorylation of carboxyl-terminal eIF2α by SPA kinases contributes to enhanced translation efficiency during photomorphogenesis. Nat Commun 2024; 15:3467. [PMID: 38658612 PMCID: PMC11043401 DOI: 10.1038/s41467-024-47848-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 04/11/2024] [Indexed: 04/26/2024] Open
Abstract
Light triggers an enhancement of global translation during photomorphogenesis in Arabidopsis, but little is known about the underlying mechanisms. The phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) at a conserved serine residue in the N-terminus has been shown as an important mechanism for the regulation of protein synthesis in mammalian and yeast cells. However, whether the phosphorylation of this residue in plant eIF2α plays a role in regulation of translation remains elusive. Here, we show that the quadruple mutant of SUPPRESSOR OF PHYA-105 family members (SPA1-SPA4) display repressed translation efficiency after light illumination. Moreover, SPA1 directly phosphorylates the eIF2α C-terminus under light conditions. The C-term-phosphorylated eIF2α promotes translation efficiency and photomorphogenesis, whereas the C-term-unphosphorylated eIF2α results in a decreased translation efficiency. We also demonstrate that the phosphorylated eIF2α enhances ternary complex assembly by promoting its affinity to eIF2β and eIF2γ. This study reveals a unique mechanism by which light promotes translation via SPA1-mediated phosphorylation of the C-terminus of eIF2α in plants.
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Affiliation(s)
- Hui-Hsien Chang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Lin-Chen Huang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Karen S Browning
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Enamul Huq
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Mei-Chun Cheng
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.
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3
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Jones AC, Wu J, Taylor SS. How an intrinsically disordered regulatory subunit assembles a PP1:eIF2 complex. Cell Rep 2024; 43:114011. [PMID: 38573854 DOI: 10.1016/j.celrep.2024.114011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 04/06/2024] Open
Abstract
Fatalska et al.1 use an interdisciplinary strategy to elucidate how an intrinsically disordered regulatory subunit of protein phosphatase 1 binds trimeric eIF2 and positions the phosphatase-substrate complex for dephosphorylation. As validation, they show that a disease mutation abolishes the interaction.
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Affiliation(s)
- Alexander C Jones
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jian Wu
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
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4
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Puig-Segui MS, Decker CJ, Barlit H, Labunskyy VM, Parker R, Puig S. Regulation of translation in response to iron deficiency in human cells. Sci Rep 2024; 14:8451. [PMID: 38605136 PMCID: PMC11009288 DOI: 10.1038/s41598-024-59003-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
Protein synthesis is a highly energy-consuming process that is downregulated in response to many environmental stresses or adverse conditions. Studies in the yeast Saccharomyces cerevisiae have shown that bulk translation is inhibited during adaptation to iron deficiency, which is consistent with its requirement for ribosome biogenesis and recycling. Although iron deficiency anemia is the most common human nutritional disorder, how iron modulates translation in mammals is poorly understood. Studies during erythropoiesis have shown that iron bioavailability is coordinated with globin synthesis via bulk translation regulation. However, little is known about the control of translation during iron limitation in other tissues. Here, we investigated how iron depletion affects protein synthesis in human osteosarcoma U-2 OS cells. By adding an extracellular iron chelator, we observed that iron deficiency limits cell proliferation, induces autophagy, and decreases the global rate of protein synthesis. Analysis of specific molecular markers indicates that the inhibition of bulk translation upon iron limitation occurs through the eukaryotic initiation factor eIF2α and mechanistic target of rapamycin (mTOR) pathways. In contrast to other environmental and nutritional stresses, iron depletion does not trigger the assembly of messenger ribonucleoprotein stress granules, which typically form upon polysome disassembly.
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Affiliation(s)
- Mireia S Puig-Segui
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural (ETSIAMN), Universidad Politécnica de Valencia (UPV), Valencia, Spain
| | - Carolyn J Decker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Hanna Barlit
- Department of Dermatology, Boston University School of Medicine, Boston, MA, 02118, USA
| | | | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Calle Catedrático Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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5
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Shanmugam R, Anderson R, Schiemann AH, Sattlegger E. Evidence that Xrn1 is in complex with Gcn1, and is required for full levels of eIF2α phosphorylation. Biochem J 2024; 481:481-498. [PMID: 38440860 DOI: 10.1042/bcj20220531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/04/2024] [Accepted: 03/05/2024] [Indexed: 03/06/2024]
Abstract
The protein kinase Gcn2 and its effector protein Gcn1 are part of the general amino acid control signalling (GAAC) pathway best known in yeast for its function in maintaining amino acid homeostasis. Under amino acid limitation, Gcn2 becomes activated, subsequently increasing the levels of phosphorylated eIF2α (eIF2α-P). This leads to the increased translation of transcriptional regulators, such as Gcn4 in yeast and ATF4 in mammals, and subsequent re-programming of the cell's gene transcription profile, thereby allowing cells to cope with starvation. Xrn1 is involved in RNA decay, quality control and processing. We found that Xrn1 co-precipitates Gcn1 and Gcn2, suggesting that these three proteins are in the same complex. Growth under starvation conditions was dependent on Xrn1 but not on Xrn1-ribosome association, and this correlated with reduced eIF2α-P levels. Constitutively active Gcn2 leads to a growth defect due to eIF2α-hyperphosphorylation, and we found that this phenotype was independent of Xrn1, suggesting that xrn1 deletion does not enhance eIF2α de-phosphorylation. Our study provides evidence that Xrn1 is required for efficient Gcn2 activation, directly or indirectly. Thus, we have uncovered a potential new link between RNA metabolism and the GAAC.
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Affiliation(s)
- Renuka Shanmugam
- School of Natural Sciences, Massey University, Auckland, New Zealand
| | - Reuben Anderson
- School of Natural Sciences, Massey University, Auckland, New Zealand
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Anja H Schiemann
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Evelyn Sattlegger
- School of Natural Sciences, Massey University, Auckland, New Zealand
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
- Maurice Wilkins Centre for Molecular BioDiscovery, Massey University, Palmerston North, New Zealand
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6
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Chen Y, McDonald JA. Collective cell migration relies on PPP1R15-mediated regulation of the endoplasmic reticulum stress response. Curr Biol 2024; 34:1390-1402.e4. [PMID: 38428416 PMCID: PMC11003853 DOI: 10.1016/j.cub.2024.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 12/19/2023] [Accepted: 02/07/2024] [Indexed: 03/03/2024]
Abstract
Collective cell migration is integral to many developmental and disease processes. Previously, we discovered that protein phosphatase 1 (Pp1) promotes border cell collective migration in the Drosophila ovary. We now report that the Pp1 phosphatase regulatory subunit dPPP1R15 is a critical regulator of border cell migration. dPPP1R15 is an ortholog of mammalian PPP1R15 proteins that attenuate the endoplasmic reticulum (ER) stress response. We show that, in collectively migrating border cells, dPPP1R15 phosphatase restrains an active physiological protein kinase R-like ER kinase- (PERK)-eIF2α-activating transcription factor 4 (ATF4) stress pathway. RNAi knockdown of dPPP1R15 blocks border cell delamination from the epithelium and subsequent migration, increases eIF2α phosphorylation, reduces translation, and drives expression of the stress response transcription factor ATF4. We observe similar defects upon overexpression of ATF4 or the eIF2α kinase PERK. Furthermore, we show that normal border cells express markers of the PERK-dependent ER stress response and require PERK and ATF4 for efficient migration. In many other cell types, unresolved ER stress induces initiation of apoptosis. In contrast, border cells with chronic RNAi knockdown of dPPP1R15 survive. Together, our results demonstrate that the PERK-eIF2α-ATF4 pathway, regulated by dPPP1R15 activity, counteracts the physiological ER stress that occurs during collective border cell migration. We propose that in vivo collective cell migration is intrinsically "stressful," requiring tight homeostatic control of the ER stress response for collective cell cohesion, dynamics, and movement.
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Affiliation(s)
- Yujun Chen
- Division of Biology, Kansas State University, 1717 Claflin Road, Manhattan, KS 66506, USA
| | - Jocelyn A McDonald
- Division of Biology, Kansas State University, 1717 Claflin Road, Manhattan, KS 66506, USA.
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7
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Yan Y, Shetty M, Harding HP, George G, Zyryanova A, Labbé K, Mafi A, Hao Q, Sidrauski C, Ron D. Substrate recruitment via eIF2γ enhances catalytic efficiency of a holophosphatase that terminates the integrated stress response. Proc Natl Acad Sci U S A 2024; 121:e2320013121. [PMID: 38547060 PMCID: PMC10998612 DOI: 10.1073/pnas.2320013121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 02/16/2024] [Indexed: 04/02/2024] Open
Abstract
Dephosphorylation of pSer51 of the α subunit of translation initiation factor 2 (eIF2αP) terminates signaling in the integrated stress response (ISR). A trimeric mammalian holophosphatase comprised of a protein phosphatase 1 (PP1) catalytic subunit, the conserved C-terminally located ~70 amino acid core of a substrate-specific regulatory subunit (PPP1R15A/GADD34 or PPP1R15B/CReP) and G-actin (an essential cofactor) efficiently dephosphorylate eIF2αP in vitro. Unlike their viral or invertebrate counterparts, with whom they share the conserved 70 residue core, the mammalian PPP1R15s are large proteins of more than 600 residues. Genetic and cellular observations point to a functional role for regions outside the conserved core of mammalian PPP1R15A in dephosphorylating its natural substrate, the eIF2 trimer. We have combined deep learning technology, all-atom molecular dynamics simulations, X-ray crystallography, and biochemistry to uncover binding of the γ subunit of eIF2 to a short helical peptide repeated four times in the functionally important N terminus of human PPP1R15A that extends past its conserved core. Binding entails insertion of Phe and Trp residues that project from one face of an α-helix formed by the conserved repeats of PPP1R15A into a hydrophobic groove exposed on the surface of eIF2γ in the eIF2 trimer. Replacing these conserved Phe and Trp residues with Ala compromises PPP1R15A function in cells and in vitro. These findings suggest mechanisms by which contacts between a distant subunit of eIF2 and elements of PPP1R15A distant to the holophosphatase active site contribute to dephosphorylation of eIF2αP by the core PPP1R15 holophosphatase and to efficient termination of the ISR in mammals.
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Affiliation(s)
- Yahui Yan
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, CambridgeCB2 0XY, United Kingdom
| | - Maithili Shetty
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, CambridgeCB2 0XY, United Kingdom
| | - Heather P. Harding
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, CambridgeCB2 0XY, United Kingdom
| | - Ginto George
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, CambridgeCB2 0XY, United Kingdom
| | - Alisa Zyryanova
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, CambridgeCB2 0XY, United Kingdom
| | | | | | - Qi Hao
- Calico Life Sciences, South San Francisco, CA94080
| | | | - David Ron
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, CambridgeCB2 0XY, United Kingdom
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8
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Dine E, Youle RJ. Integrating the response to stressed mitochondria. Mol Cell 2024; 84:995-997. [PMID: 38518749 DOI: 10.1016/j.molcel.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 02/23/2024] [Accepted: 02/23/2024] [Indexed: 03/24/2024]
Abstract
Chakrabarty et al.1 demonstrate that phospho-EIF2α (pEIF2α), the translation initiation factor that mediates the integrated stress response (ISR), is necessary and sufficient for the autophagic degradation of mitochondria following the addition of mitochondrial stressors.
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Affiliation(s)
- Elliot Dine
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Richard J Youle
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
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9
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Jin B, Wang M, Sun Y, Lee PAH, Zhang X, Lu Y, Zhao B. CHIP suppresses the proliferation and migration of A549 cells by mediating the ubiquitination of eIF2α and upregulation of tumor suppressor RBM5. J Biol Chem 2024; 300:105673. [PMID: 38272235 PMCID: PMC10877634 DOI: 10.1016/j.jbc.2024.105673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/05/2024] [Indexed: 01/27/2024] Open
Abstract
The protein kinase RNA-like endoplasmic reticulum kinase (PERK)-eukaryotic translation initiation factor 2 subunit α (eIF2α) pathway plays an essential role in endoplasmic reticulum (ER) stress. When the PERK-eIF2α pathway is activated, PERK phosphorylates eIF2α (p-eIF2α) at Ser51 and quenches global protein synthesis. In this study, we verified eIF2α as a bona fide substrate of the E3 ubiquitin ligase carboxyl terminus of the HSC70-interaction protein (CHIP) both in vitro and in cells. CHIP mediated the ubiquitination and degradation of nonphosphorylated eIF2α in a chaperone-independent manner and promoted the upregulation of the cyclic AMP-dependent transcription factor under endoplasmic reticulum stress conditions. Cyclic AMP-dependent transcription factor induced the transcriptional enhancement of the tumor suppressor genes PTEN and RBM5. Although transcription was enhanced, the PTEN protein was subsequently degraded by CHIP, but the expression of the RBM5 protein was upregulated, thereby suppressing the proliferation and migration of A549 cells. Overall, our study established a new mechanism that deepened the understanding of the PERK-eIF2α pathway through the ubiquitination and degradation of eIF2α. The crosstalk between the phosphorylation and ubiquitination of eIF2α shed light on a new perspective for tumor progression.
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Affiliation(s)
- Bo Jin
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Mengran Wang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Yiheng Sun
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Priscilla Ann Hweek Lee
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Xiangqi Zhang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Yao Lu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Zhao
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, and School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, China.
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10
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Misra J, Carlson KR, Spandau DF, Wek RC. Multiple mechanisms activate GCN2 eIF2 kinase in response to diverse stress conditions. Nucleic Acids Res 2024; 52:1830-1846. [PMID: 38281137 PMCID: PMC10899773 DOI: 10.1093/nar/gkae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/22/2023] [Accepted: 01/02/2024] [Indexed: 01/30/2024] Open
Abstract
Diverse environmental insults induce the integrated stress response (ISR), which features eIF2 phosphorylation and translational control that serves to restore protein homeostasis. The eIF2 kinase GCN2 is a first responder in the ISR that is activated by amino acid depletion and other stresses not directly related to nutrients. Two mechanisms are suggested to trigger an ordered process of GCN2 activation during stress: GCN2 monitoring stress via accumulating uncharged tRNAs or by stalled and colliding ribosomes. Our results suggest that while ribosomal collisions are indeed essential for GCN2 activation in response to translational elongation inhibitors, conditions that trigger deacylation of tRNAs activate GCN2 via its direct association with affected tRNAs. Both mechanisms require the GCN2 regulatory domain related to histidyl tRNA synthetases. GCN2 activation by UV irradiation features lowered amino acids and increased uncharged tRNAs and UV-induced ribosome collisions are suggested to be dispensable. We conclude that there are multiple mechanisms that activate GCN2 during diverse stresses.
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Affiliation(s)
- Jagannath Misra
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4067 Indianapolis, Indiana 46202, USA
| | - Kenneth R Carlson
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4067 Indianapolis, Indiana 46202, USA
| | - Dan F Spandau
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4067 Indianapolis, Indiana 46202, USA
- Department of Dermatology, Indiana University School of Medicine, 635 Barnhill Drive, MS4067 Indianapolis, Indiana 46202, USA
- Richard L. Roudebush Veterans Administration Medical Center, Indiana University School of Medicine, 635 Barnhill Drive, MS4067 Indianapolis, Indiana 46202, USA
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4067 Indianapolis, Indiana 46202, USA
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11
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Hu Q, Qiu L, Ge L, Wei Y. Sevoflurane postconditioning alleviates hypoxic-ischemic brain damage in rats by inhibiting the endoplasmic reticulum stress PERK/ATF4/CHOP pathway. Tissue Cell 2024; 86:102289. [PMID: 38194851 DOI: 10.1016/j.tice.2023.102289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 01/11/2024]
Abstract
Hypoxic-ischemic brain damage (HIBD) frequently induces cognitive impairments. Investigating the role of sevoflurane postconditioning (SPC) in HIBD, we conducted experiments involving HIBD modeling, SPC treatment, and interventions with the PERK inhibitor GSK2656157 or the PERK activator CCT020312, administered 30 min before modeling, followed by SPC treatment. Behavioral testing using the Morris water maze test and Neurological Deficiency Scale (NDS) was conducted. Additionally, Nissl staining assessed hippocampal CA1 area neuronal density, TUNEL staining evaluated hippocampal CA1 area neuronal apoptosis, and Western blot determined hippocampal CA1 area protein levels, including Bax, Bcl-2, p-PERK/PERK, p-eIF2/eIF2, ATF4, CHOP, GRP78, Bax, and Bcl-2 protein levels. Following SPC treatment, HIBD rats exhibited improved spatial learning and memory abilities, reduced neuronal apoptosis, increased neuronal density in the hippocampal CA1 area, elevated Bcl-2 protein level, decreased Bax protein levels, and decreased levels of endoplasmic reticulum stress pathway related proteins (p-PERK/PERK, p-eIF2/eIF2, ATF4, CHOP and GRP78). Pre-modeling treatment with the PERK inhibitor treatment improved outcomes in HIBD rats. However, pre-modeling treatment with the PERK activator CCT020312 counteracted the protective effects of SPC against HIBD in rats. In conclusion, SPC alleviates neuronal apoptosis in the hippocampus CA1 area of HIBD rats by inhibiting the endoplasmic reticulum stress pathway PERK/ATF4/CHOP, thereby mitigating HIBD in rats.
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Affiliation(s)
- Qionghua Hu
- Gansu Prov Hosp, Dept Anesthesiol, Lanzhou 730000, PR China
| | - Lingqin Qiu
- Gansu Prov Hosp, Dept Anesthesiol, Lanzhou 730000, PR China
| | - Li Ge
- Gansu Prov Hosp, Dept Anesthesiol, Lanzhou 730000, PR China
| | - Yi Wei
- Gansu Prov Hosp, Dept Anesthesiol, Lanzhou 730000, PR China.
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12
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Dolliver SM, Galbraith C, Khaperskyy DA. Human Betacoronavirus OC43 Interferes with the Integrated Stress Response Pathway in Infected Cells. Viruses 2024; 16:212. [PMID: 38399988 PMCID: PMC10893100 DOI: 10.3390/v16020212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/20/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
Viruses evolve many strategies to ensure the efficient synthesis of their proteins. One such strategy is the inhibition of the integrated stress response-the mechanism through which infected cells arrest translation through the phosphorylation of the alpha subunit of the eukaryotic translation initiation factor 2 (eIF2α). We have recently shown that the human common cold betacoronavirus OC43 actively inhibits eIF2α phosphorylation in response to sodium arsenite, a potent inducer of oxidative stress. In this work, we examined the modulation of integrated stress responses by OC43 and demonstrated that the negative feedback regulator of eIF2α phosphorylation GADD34 is strongly induced in infected cells. However, the upregulation of GADD34 expression induced by OC43 was independent from the activation of the integrated stress response and was not required for the inhibition of eIF2α phosphorylation in virus-infected cells. Our work reveals a complex interplay between the common cold coronavirus and the integrated stress response, in which efficient viral protein synthesis is ensured by the inhibition of eIF2α phosphorylation but the GADD34 negative feedback loop is disrupted.
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Affiliation(s)
| | | | - Denys A. Khaperskyy
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
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13
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Amiri M, Kiniry SJ, Possemato AP, Mahmood N, Basiri T, Dufour CR, Tabatabaei N, Deng Q, Bellucci MA, Harwalkar K, Stokes MP, Giguère V, Kaufman RJ, Yamanaka Y, Baranov PV, Tahmasebi S, Sonenberg N. Impact of eIF2α phosphorylation on the translational landscape of mouse embryonic stem cells. Cell Rep 2024; 43:113615. [PMID: 38159280 PMCID: PMC10962698 DOI: 10.1016/j.celrep.2023.113615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 10/24/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024] Open
Abstract
The integrated stress response (ISR) is critical for cell survival under stress. In response to diverse environmental cues, eIF2α becomes phosphorylated, engendering a dramatic change in mRNA translation. The activation of ISR plays a pivotal role in the early embryogenesis, but the eIF2-dependent translational landscape in pluripotent embryonic stem cells (ESCs) is largely unexplored. We employ a multi-omics approach consisting of ribosome profiling, proteomics, and metabolomics in wild-type (eIF2α+/+) and phosphorylation-deficient mutant eIF2α (eIF2αA/A) mouse ESCs (mESCs) to investigate phosphorylated (p)-eIF2α-dependent translational control of naive pluripotency. We show a transient increase in p-eIF2α in the naive epiblast layer of E4.5 embryos. Absence of eIF2α phosphorylation engenders an exit from naive pluripotency following 2i (two chemical inhibitors of MEK1/2 and GSK3α/β) withdrawal. p-eIF2α controls translation of mRNAs encoding proteins that govern pluripotency, chromatin organization, and glutathione synthesis. Thus, p-eIF2α acts as a key regulator of the naive pluripotency gene regulatory network.
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Affiliation(s)
- Mehdi Amiri
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Stephen J Kiniry
- School of Biochemistry and Cell Biology, University College Cork, T12 XF62 Cork, Ireland
| | | | - Niaz Mahmood
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Tayebeh Basiri
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Catherine R Dufour
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Qiyun Deng
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Michael A Bellucci
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Keerthana Harwalkar
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada; Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada
| | - Matthew P Stokes
- Cell Signaling Technology, Inc., 3 Trask Lane, Danvers, MA 01923, USA
| | - Vincent Giguère
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada
| | - Randal J Kaufman
- Degenerative Diseases Program, Center for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Yojiro Yamanaka
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada; Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, T12 XF62 Cork, Ireland
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA.
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC H3A 1A3, Canada.
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Kaempfer R. RNA Activators of Stress Kinase PKR within Human Genes That Control Splicing or Translation Create Novel Targets for Hereditary Diseases. Int J Mol Sci 2024; 25:1323. [PMID: 38279321 PMCID: PMC10816128 DOI: 10.3390/ijms25021323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/14/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024] Open
Abstract
Specific sequences within RNA encoded by human genes essential for survival possess the ability to activate the RNA-dependent stress kinase PKR, resulting in phosphorylation of its substrate, eukaryotic translation initiation factor-2α (eIF2α), either to curb their mRNA translation or to enhance mRNA splicing. Thus, interferon-γ (IFNG) mRNA activates PKR through a 5'-terminal 203-nucleotide pseudoknot structure, thereby strongly downregulating its own translation and preventing a harmful hyper-inflammatory response. Tumor necrosis factor-α (TNF) pre-mRNA encodes within the 3'-untranslated region (3'-UTR) a 104-nucleotide RNA pseudoknot that activates PKR to enhance its splicing by an order of magnitude while leaving mRNA translation intact, thereby promoting effective TNF protein expression. Adult and fetal globin genes encode pre-mRNA structures that strongly activate PKR, leading to eIF2α phosphorylation that greatly enhances spliceosome assembly and splicing, yet also structures that silence PKR activation upon splicing to allow for unabated globin mRNA translation essential for life. Regulatory circuits resulting in each case from PKR activation were reviewed previously. Here, we analyze mutations within these genes created to delineate the RNA structures that activate PKR and to deconvolute their folding. Given the critical role of intragenic RNA activators of PKR in gene regulation, such mutations reveal novel potential RNA targets for human disease.
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Affiliation(s)
- Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University, Jerusalem 9112102, Israel
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15
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Li C, Zhang H, Mo J, Zuo J, Ye L. Caspase-3/GSDME dependent pyroptosis contributes to offspring lung injury induced by gestational PFOS exposure via PERK/ATF4 signaling. Arch Toxicol 2024; 98:207-221. [PMID: 37955688 PMCID: PMC10761489 DOI: 10.1007/s00204-023-03626-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/12/2023] [Indexed: 11/14/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is widely used in industry and consumer products. Previous studies have showed that PFOS gestational exposure is associated with offspring lung damage in rat. However, the underlying mechanisms remain poorly understood. In this study, we investigated the role of gasdermin E (GSDME) in lung injury of offspring and its underlying mechanisms using in vivo and in vitro approaches. Pregnant SD rats were exposed to PFOS (1 mg/kg BW/d) between gestational day 12-18, and the lung tissue of the offspring was evaluated on postnatal day 7. PFOS treated animals exhibited alveolar septal thickening and inflammation-related damages, with an increased expression of GSDME in alveolar type II epithelial cells (AECII). Furthermore, in vitro experiments demonstrated that PFOS exposure (with 225 μM and up) upregulated the caspase-3/GSDME signaling pathway in AECII. Also, ultrastructure analysis revealed significant changes in the endoplasmic reticulum (ER) structure in PFOS-induced pyroptotic cells, which is consistent with the ER stress detected in these cells. Additionally, PFOS exposure led to increased expression of ER stress-related proteins, including p-PERK, p-eIF2α, ATF4, and CHOP. Subsequently, using specific inhibitors, we found that the PERK/ATF4 pathway acted as an upstream signal regulating GSDME-dependent pyroptosis. Overall, our findings show that GSDME-dependent pyroptosis plays a crucial role in the lung injury induced by gestational PFOS exposure, and the PERK/ATF4 pathway may function as a possible mediator of this process.
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Affiliation(s)
- Cong Li
- Department of Pediatrics, Peking University First Hospital, No.1 Xi'an Men Street, West District, Beijing, 100034, China
| | - Huishan Zhang
- Department of Pediatrics, Peking University First Hospital, No.1 Xi'an Men Street, West District, Beijing, 100034, China
- Department of Respiratory Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200120, China
| | - Jiali Mo
- Department of Pediatrics, Peking University First Hospital, No.1 Xi'an Men Street, West District, Beijing, 100034, China
| | - Jingye Zuo
- Department of Pediatrics, Peking University First Hospital, No.1 Xi'an Men Street, West District, Beijing, 100034, China
| | - Leping Ye
- Department of Pediatrics, Peking University First Hospital, No.1 Xi'an Men Street, West District, Beijing, 100034, China.
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16
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Yuan Y, Liu S, Yang H, Xu J, Zhai J, Jiang H, Sun B. Acetylshikonin induces apoptosis through the endoplasmic reticulum stress-activated PERK/eIF 2α /CHOP axis in oesophageal squamous cell carcinoma. J Cell Mol Med 2024; 28:e18030. [PMID: 37929884 PMCID: PMC10807581 DOI: 10.1111/jcmm.18030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/17/2023] [Accepted: 10/25/2023] [Indexed: 11/07/2023] Open
Abstract
Acetylshikonin (AS) is an active component of Lithospermum erythrorhizon Sieb. et Zucc that exhibits activity against various cancers; however, the underlying mechanisms of AS against oesophageal squamous carcinoma (ESCC) need to be elusive. The research explores the anti-cancer role and potential mechanism of AS on ESCC in vitro and in vivo, providing evidences for AS treatment against ESCC. In this study, we firstly demonstrated that AS treatment effectively inhibits cell viability and proliferation of ESCC cells. In addition, AS significantly induces G1/S phage arrest and promotes apoptosis in ESCC cell lines. Further studies reveal that AS induces ER stress, as observed by dose- and time-dependently increased expression of BIP, PDI, PERK, phosphorylation of eIF2α , CHOP and splicing of XBP1. CHOP knockdown or PERK inhibition markedly rescue cell apoptosis induced by AS. Moreover, AS treatment significantly inhibits ESCC xenograft growth in nude mice. Elevated expression of BIP and CHOP is also observed in xenograft tumours. Taken together, AS inhibits proliferation and induces apoptosis through ER stress-activated PERK/eIF2α /CHOP pathway in ESCC, which indicates AS represents a promising candidate for ESCC treatment.
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Affiliation(s)
- Ya‐Jiao Yuan
- Department of Biochemistry and Molecular Biology, College of Clinical and Basic MedicineShandong First Medical University & Shandong academy of medical sciencesJinanChina
- Department of Clinical LaboratoryQingdao Jimo People's HospitalQingdaoChina
| | - Shanshan Liu
- Department of Biochemistry and Molecular Biology, College of Clinical and Basic MedicineShandong First Medical University & Shandong academy of medical sciencesJinanChina
| | - Hong Yang
- Department of Clinical LaboratoryTaian Central HospitalChina
| | - Jian‐Ling Xu
- Department of Biochemistry and Molecular Biology, College of Clinical and Basic MedicineShandong First Medical University & Shandong academy of medical sciencesJinanChina
| | - Jing Zhai
- Department of Biochemistry and Molecular Biology, College of Clinical and Basic MedicineShandong First Medical University & Shandong academy of medical sciencesJinanChina
| | - Han‐Ming Jiang
- Department of Biochemistry and Molecular Biology, College of Clinical and Basic MedicineShandong First Medical University & Shandong academy of medical sciencesJinanChina
| | - Beibei Sun
- Department of Biochemistry and Molecular Biology, College of Clinical and Basic MedicineShandong First Medical University & Shandong academy of medical sciencesJinanChina
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17
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Hicks D, Giresh K, Wrischnik LA, Weiser DC. The PPP1R15 Family of eIF2-alpha Phosphatase Targeting Subunits (GADD34 and CReP). Int J Mol Sci 2023; 24:17321. [PMID: 38139150 PMCID: PMC10743859 DOI: 10.3390/ijms242417321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The vertebrate PPP1R15 family consists of the proteins GADD34 (growth arrest and DNA damage-inducible protein 34, the product of the PPP1R15A gene) and CReP (constitutive repressor of eIF2α phosphorylation, the product of the PPP1R15B gene), both of which function as targeting/regulatory subunits for protein phosphatase 1 (PP1) by regulating subcellular localization, modulating substrate specificity and assembling complexes with target proteins. The primary cellular function of these proteins is to facilitate the dephosphorylation of eukaryotic initiation factor 2-alpha (eIF2α) by PP1 during cell stress. In this review, we will provide a comprehensive overview of the cellular function, biochemistry and pharmacology of GADD34 and CReP, starting with a brief introduction of eIF2α phosphorylation via the integrated protein response (ISR). We discuss the roles GADD34 and CReP play as feedback inhibitors of the unfolded protein response (UPR) and highlight the critical function they serve as inhibitors of the PERK-dependent branch, which is particularly important since it can mediate cell survival or cell death, depending on how long the stressful stimuli lasts, and GADD34 and CReP play key roles in fine-tuning this cellular decision. We briefly discuss the roles of GADD34 and CReP homologs in model systems and then focus on what we have learned about their function from knockout mice and human patients, followed by a brief review of several diseases in which GADD34 and CReP have been implicated, including cancer, diabetes and especially neurodegenerative disease. Because of the potential importance of GADD34 and CReP in aspects of human health and disease, we will discuss several pharmacological inhibitors of GADD34 and/or CReP that show promise as treatments and the controversies as to their mechanism of action. This review will finish with a discussion of the biochemical properties of GADD34 and CReP, their regulation and the additional interacting partners that may provide insight into the roles these proteins may play in other cellular pathways. We will conclude with a brief outline of critical areas for future study.
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Affiliation(s)
- Danielle Hicks
- Department of Science, Mathematics and Engineering, Modesto Junior College, Modesto, CA 95350, USA
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Krithika Giresh
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Lisa A. Wrischnik
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Douglas C. Weiser
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
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18
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He S, Huang C, Tan N, Zhang J. Oridonin Promotes Apoptosis in Rheumatoid Arthritis Fibroblast-like Synoviocytes Through PERK/eIF2α/CHOP of Endoplasmic Reticulum Stress Pathway. DNA Cell Biol 2023; 42:711-719. [PMID: 37862122 DOI: 10.1089/dna.2023.0244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2023] Open
Abstract
Oridonin (ORI), derived from Chinese herbs Rabdosia rubescens, has anti-inflammatory, proapoptotic, anticancer effects. Previous studies have found that ORI induces apoptosis in rheumatoid arthritis fibroblast synovial cells (RA-FLSs), but this mechanism is not clear. We will investigate the apoptosis mechanism of ORI on RA-FLSs. RA-FLSs were treated with various concentrations of ORI (0, 5, 10, 15, 20, 25, and 30 μM) for 24 h. CCK8, LDH, and hochest/PI assay determined the viability, cytotoxicity, and death of ORI on RA-FLSs. The endoplasmic reticulum probe was used to observe structural changes of endoplasmic reticulum in RA-FLSs. RNA expression was detected with RNA sequencing analysis and quantitative real-time PCR. The PERK/eIF2α/CHOP pathway protein of the endoplasmic reticulum was verified with Western Blot. Our results show that ORI induced the apoptosis of RA-FLSs from CCK8, LDH, and Hochest/PI. The endoplasmic reticulum distribution was altered in RA-FLSs after being treated with ORI. Bioinformatics analysis of RNA sequencing data found that 1453 genes were elevated. The PERK/eIF2α/CHOP pathway of the endoplasmic reticulum was regulated from the Gene ontology and KEGG analysis. The results of quantitative real-time PCR and Western blot analysis verified the regulation of PERK/eIF2α/CHOP pathway in RA-FLSs. Our data imply that the endoplasmic reticulum's PERK/eIF2α/CHOP signaling pathway is certainly implicated in the induction of RA-FLS apoptosis by ORI. This study has important implications for the pharmacological effects of ORI and the treatment of RA.
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Affiliation(s)
- Shoudi He
- The Department of Rheumatology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen, China
- Guangzhou University of Chinese Medicine, Shenzhen, China
- Traditional Chinese Medicine Department of Rheumatism, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Changsheng Huang
- Traditional Chinese Medicine Department of Rheumatism, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Ning Tan
- Traditional Chinese Medicine Department of Rheumatism, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Jianyong Zhang
- The Department of Rheumatology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen, China
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19
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Aleksashin NA, Chang STL, Cate JHD. A highly efficient human cell-free translation system. RNA 2023; 29:1960-1972. [PMID: 37793791 PMCID: PMC10653386 DOI: 10.1261/rna.079825.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 09/21/2023] [Indexed: 10/06/2023]
Abstract
Cell-free protein synthesis (CFPS) systems enable easy in vitro expression of proteins with many scientific, industrial, and therapeutic applications. Here we present an optimized, highly efficient human cell-free translation system that bypasses many limitations of currently used in vitro systems. This CFPS system is based on extracts from human HEK293T cells engineered to endogenously express GADD34 and K3L proteins, which suppress phosphorylation of translation initiation factor eIF2α. Overexpression of GADD34 and K3L proteins in human cells before cell lysate preparation significantly simplifies lysate preparation. We find that expression of the GADD34 and K3L accessory proteins before cell lysis maintains low levels of phosphorylation of eIF2α in the extracts. During in vitro translation reactions, eIF2α phosphorylation increases moderately in a GCN2-dependent fashion that can be inhibited by GCN2 kinase inhibitors. This new CFPS system should be useful for exploring human translation mechanisms in more physiological conditions outside the cell.
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Affiliation(s)
- Nikolay A Aleksashin
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, California 94720, USA
| | - Stacey Tsai-Lan Chang
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, California 94720, USA
| | - Jamie H D Cate
- Innovative Genomics Institute, University of California-Berkeley, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, California 94720, USA
- Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, USA
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20
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Liu A, Chen Z, Li X, Xie C, Chen Y, Su X, Chen Y, Zhang M, Chen J, Yang T, Shen J, Huang H. C5a-C5aR1 induces endoplasmic reticulum stress to accelerate vascular calcification via PERK-eIF2α-ATF4-CREB3L1 pathway. Cardiovasc Res 2023; 119:2563-2578. [PMID: 37603848 DOI: 10.1093/cvr/cvad133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 04/13/2023] [Accepted: 05/02/2023] [Indexed: 08/23/2023] Open
Abstract
AIMS Vascular calcification (VC) predicts the morbidity and mortality in cardiovascular diseases. Vascular smooth muscle cells (VSMCs) osteogenic transdifferentiation is the crucial pathological basis for VC. To date, the molecular pathogenesis is still largely unclear. Notably, C5a-C5aR1 contributes to the development of cardiovascular diseases, and its closely related to physiological bone mineralization which is similar to VSMCs osteogenic transdifferentiation. However, the role and underlying mechanisms of C5a-C5aR1 in VC remain unexplored. METHODS AND RESULTS A cross-sectional clinical study was utilized to examine the association between C5a and VC. Chronic kidney diseases mice and calcifying VSMCs models were established to investigate the effect of C5a-C5aR1 in VC, evaluated by changes in calcium deposition and osteogenic markers. The cross-sectional study identified that high level of C5a was associated with increased risk of VC. C5a dose-responsively accelerated VSMCs osteogenic transdifferentiation accompanying with increased the expression of C5aR1. Meanwhile, the antagonists of C5aR1, PMX 53, reduced calcium deposition, and osteogenic transdifferentiation both in vivo and in vitro. Mechanistically, C5a-C5aR1 induced endoplasmic reticulum (ER) stress and then activated PERK-eIF2α-ATF4 pathway to accelerated VSMCs osteogenic transdifferentiation. In addition, cAMP-response element-binding protein 3-like 1 (CREB3L1) was a key downstream mediator of PERK-eIF2α-ATF4 pathway which accelerated VSMCs osteogenic transdifferentiation by promoting the expression of COL1α1. CONCLUSIONS High level of C5a was associated with increased risk of VC, and it accelerated VC by activating the receptor C5aR1. PERK-eIF2α-ATF4-CREB3L1 pathway of ER stress was activated by C5a-C5aR1, hence promoting VSMCs osteogenic transdifferentiation. Targeting C5 or C5aR1 may be an appealing therapeutic target for VC.
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Affiliation(s)
- Aiting Liu
- Department of Cardiology, Joint Laboratory of Guangdong-Hong Kong-Macao Universities for Nutritional Metabolism and Precise Prevention and Control of Major Chronic Diseases, The Eighth Affiliated Hospital of Sun Yat-sen University, Shennan Middle Rd, Shenzhen, 518000, China
| | - Zhenwei Chen
- Department of Nephrology, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518000, China
| | - Xiaoxue Li
- Department of Cardiology, Joint Laboratory of Guangdong-Hong Kong-Macao Universities for Nutritional Metabolism and Precise Prevention and Control of Major Chronic Diseases, The Eighth Affiliated Hospital of Sun Yat-sen University, Shennan Middle Rd, Shenzhen, 518000, China
| | - Chen Xie
- Department of Cardiology, Joint Laboratory of Guangdong-Hong Kong-Macao Universities for Nutritional Metabolism and Precise Prevention and Control of Major Chronic Diseases, The Eighth Affiliated Hospital of Sun Yat-sen University, Shennan Middle Rd, Shenzhen, 518000, China
| | - Yanlian Chen
- Department of Cardiology, Joint Laboratory of Guangdong-Hong Kong-Macao Universities for Nutritional Metabolism and Precise Prevention and Control of Major Chronic Diseases, The Eighth Affiliated Hospital of Sun Yat-sen University, Shennan Middle Rd, Shenzhen, 518000, China
| | - Xiaoyan Su
- Department of Nephropathy, Tungwah Hospital of Sun Yat-Sen University, Dongguan, 523000, China
| | - Ying Chen
- Department of Nephropathy, Tungwah Hospital of Sun Yat-Sen University, Dongguan, 523000, China
| | - Mengbi Zhang
- Department of Nephropathy, Tungwah Hospital of Sun Yat-Sen University, Dongguan, 523000, China
| | - Jie Chen
- Department of Radiotherapy, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, 510000, China
| | - Tiecheng Yang
- Department of Nephrology, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518000, China
| | - Jiangang Shen
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, 999077, China
| | - Hui Huang
- Department of Cardiology, Joint Laboratory of Guangdong-Hong Kong-Macao Universities for Nutritional Metabolism and Precise Prevention and Control of Major Chronic Diseases, The Eighth Affiliated Hospital of Sun Yat-sen University, Shennan Middle Rd, Shenzhen, 518000, China
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21
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Blumhagen RZ, Kurche JS, Cool CD, Walts AD, Heinz D, Fingerlin TE, Yang IV, Schwartz DA. Spatially distinct molecular patterns of gene expression in idiopathic pulmonary fibrosis. Respir Res 2023; 24:287. [PMID: 37978501 PMCID: PMC10655274 DOI: 10.1186/s12931-023-02572-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/21/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Idiopathic pulmonary fibrosis (IPF) is a heterogeneous disease that is pathologically characterized by areas of normal-appearing lung parenchyma, active fibrosis (transition zones including fibroblastic foci) and dense fibrosis. Defining transcriptional differences between these pathologically heterogeneous regions of the IPF lung is critical to understanding the distribution and extent of fibrotic lung disease and identifying potential therapeutic targets. Application of a spatial transcriptomics platform would provide more detailed spatial resolution of transcriptional signals compared to previous single cell or bulk RNA-Seq studies. METHODS We performed spatial transcriptomics using GeoMx Nanostring Digital Spatial Profiling on formalin-fixed paraffin-embedded (FFPE) tissue from 32 IPF and 12 control subjects and identified 231 regions of interest (ROIs). We compared normal-appearing lung parenchyma and airways between IPF and controls with histologically normal lung tissue, as well as histologically distinct regions within IPF (normal-appearing lung parenchyma, transition zones containing fibroblastic foci, areas of dense fibrosis, and honeycomb epithelium metaplasia). RESULTS We identified 254 differentially expressed genes (DEGs) between IPF and controls in histologically normal-appearing regions of lung parenchyma; pathway analysis identified disease processes such as EIF2 signaling (important for cap-dependent mRNA translation), epithelial adherens junction signaling, HIF1α signaling, and integrin signaling. Within IPF, we identified 173 DEGs between transition and normal-appearing lung parenchyma and 198 DEGs between dense fibrosis and normal lung parenchyma; pathways dysregulated in both transition and dense fibrotic areas include EIF2 signaling pathway activation (upstream of endoplasmic reticulum (ER) stress proteins ATF4 and CHOP) and wound healing signaling pathway deactivation. Through cell deconvolution of transcriptome data and immunofluorescence staining, we confirmed loss of alveolar parenchymal signals (AGER, SFTPB, SFTPC), gain of secretory cell markers (SCGB3A2, MUC5B) as well as dysregulation of the upstream regulator ATF4, in histologically normal-appearing tissue in IPF. CONCLUSIONS Our findings demonstrate that histologically normal-appearing regions from the IPF lung are transcriptionally distinct when compared to similar lung tissue from controls with histologically normal lung tissue, and that transition zones and areas of dense fibrosis within the IPF lung demonstrate activation of ER stress and deactivation of wound healing pathways.
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Affiliation(s)
- Rachel Z Blumhagen
- Center for Genes, Environment and Health, National Jewish Health, 1400 Jackson St, Office M222D, Denver, CO, 80206, USA.
| | - Jonathan S Kurche
- Department of Medicine, University of Colorado Anschutz Medical Campus, 13001 E. 17th Place, Aurora, CO, 80045, USA
- Medical Service, Rocky Mountain Regional Veterans Administration Medical Center, 1700 N Wheeling St, Aurora, CO, 80045, USA
| | - Carlyne D Cool
- Department of Medicine, University of Colorado Anschutz Medical Campus, 13001 E. 17th Place, Aurora, CO, 80045, USA
- Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, CO, 80206, USA
| | - Avram D Walts
- Department of Medicine, University of Colorado Anschutz Medical Campus, 13001 E. 17th Place, Aurora, CO, 80045, USA
| | - David Heinz
- Pathology Laboratory, National Jewish Health, 1400 Jackson St., Denver, CO, 80206, USA
| | - Tasha E Fingerlin
- Center for Genes, Environment and Health, National Jewish Health, 1400 Jackson St, Office M222D, Denver, CO, 80206, USA
| | - Ivana V Yang
- Department of Medicine, University of Colorado Anschutz Medical Campus, 13001 E. 17th Place, Aurora, CO, 80045, USA
| | - David A Schwartz
- Department of Medicine, University of Colorado Anschutz Medical Campus, 13001 E. 17th Place, Aurora, CO, 80045, USA
- Medical Service, Rocky Mountain Regional Veterans Administration Medical Center, 1700 N Wheeling St, Aurora, CO, 80045, USA
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22
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Ito T, Wuerth JD, Weber F. Protection of eIF2B from inhibitory phosphorylated eIF2: A viral strategy to maintain mRNA translation during the PKR-triggered integrated stress response. J Biol Chem 2023; 299:105287. [PMID: 37742919 PMCID: PMC10616414 DOI: 10.1016/j.jbc.2023.105287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023] Open
Abstract
The integrated stress response (ISR) protects cells from a variety of insults. Once elicited (e.g., by virus infections), it eventually leads to the block of mRNA translation. Central to the ISR are the interactions between translation initiation factors eIF2 and eIF2B. Under normal conditions, eIF2 drives the initiation of protein synthesis through hydrolysis of GTP, which becomes replenished by the guanine nucleotide exchange factor eIF2B. The antiviral branch of the ISR is activated by the RNA-activated kinase PKR which phosphorylates eIF2, thereby converting it into an eIF2B inhibitor. Here, we describe the recently solved structures of eIF2B in complex with eIF2 and a novel escape strategy used by viruses. While unphosphorylated eIF2 interacts with eIF2B in its "productive" conformation, phosphorylated eIF2 [eIF2(αP)] engages a different binding cavity on eIF2B and forces it into the "nonproductive" conformation that prohibits guanine nucleotide exchange factor activity. It is well established that viruses express so-called PKR antagonists that interfere with double-strand RNA, PKR itself, or eIF2. However recently, three taxonomically unrelated viruses were reported to encode antagonists targeting eIF2B instead. For one antagonist, the S segment nonstructural protein of Sandfly fever Sicilian virus, atomic structures showed that it occupies the eIF2(αP)-binding cavity on eIF2B without imposing a switch to the nonproductive conformation. S segment nonstructural protein thus antagonizes the activity of PKR by protecting eIF2B from inhibition by eIF2(αP). As the ISR and specifically eIF2B are central to neuroprotection and a wide range of genetic and age-related diseases, these developments may open new possibilities for treatments.
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Affiliation(s)
- Takuhiro Ito
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | | | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany.
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23
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Ricciardi-Jorge T, da Rocha EL, Gonzalez-Kozlova E, Rodrigues-Luiz GF, Ferguson BJ, Sweeney T, Irigoyen N, Mansur DS. PKR-mediated stress response enhances dengue and Zika virus replication. mBio 2023; 14:e0093423. [PMID: 37732809 PMCID: PMC10653888 DOI: 10.1128/mbio.00934-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 08/01/2023] [Indexed: 09/22/2023] Open
Abstract
IMPORTANCE One of the fundamental features that make viruses intracellular parasites is the necessity to use cellular translational machinery. Hence, this is a crucial checkpoint for controlling infections. Here, we show that dengue and Zika viruses, responsible for nearly 400 million infections every year worldwide, explore such control for optimal replication. Using immunocompetent cells, we demonstrate that arrest of protein translations happens after sensing of dsRNA and that the information required to avoid this blocking is contained in viral 5'-UTR. Our work, therefore, suggests that the non-canonical translation described for these viruses is engaged when the intracellular stress response is activated.
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Affiliation(s)
- Taissa Ricciardi-Jorge
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
- The Pirbright Institute, Woking, United Kingdom
| | - Edroaldo Lummertz da Rocha
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Edgar Gonzalez-Kozlova
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
- Icahn School of Medicine, New York, USA
| | - Gabriela Flavia Rodrigues-Luiz
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Brian J. Ferguson
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | | | - Nerea Irigoyen
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Daniel Santos Mansur
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
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24
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Fu Y, Sacco O, DeBitetto E, Kanshin E, Ueberheide B, Sfeir A. Mitochondrial DNA breaks activate an integrated stress response to reestablish homeostasis. Mol Cell 2023; 83:3740-3753.e9. [PMID: 37832546 DOI: 10.1016/j.molcel.2023.09.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 08/10/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023]
Abstract
Mitochondrial DNA double-strand breaks (mtDSBs) lead to the degradation of circular genomes and a reduction in copy number; yet, the cellular response in human cells remains elusive. Here, using mitochondrial-targeted restriction enzymes, we show that a subset of cells with mtDSBs exhibited defective mitochondrial protein import, reduced respiratory complexes, and loss of membrane potential. Electron microscopy confirmed the altered mitochondrial membrane and cristae ultrastructure. Intriguingly, mtDSBs triggered the integrated stress response (ISR) via the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) by DELE1 and heme-regulated eIF2α kinase (HRI). When ISR was inhibited, the cells experienced intensified mitochondrial defects and slower mtDNA recovery post-breakage. Lastly, through proteomics, we identified ATAD3A-a membrane-bound protein interacting with nucleoids-as potentially pivotal in relaying signals from impaired genomes to the inner mitochondrial membrane. In summary, our study delineates the cascade connecting damaged mitochondrial genomes to the cytoplasm and highlights the significance of the ISR in maintaining mitochondrial homeostasis amid genome instability.
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Affiliation(s)
- Yi Fu
- Skirball Institute of Biomolecular Medicine, Cell Biology Department, NYU School of Medicine, New York, NY 10016, USA; Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Olivia Sacco
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Emily DeBitetto
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Evgeny Kanshin
- Proteomics Laboratory, NYU School of Medicine, New York, NY 10016, USA; Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Beatrix Ueberheide
- Proteomics Laboratory, NYU School of Medicine, New York, NY 10016, USA; Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA; Department of Neurology, NYU School of Medicine, New York, NY 10016, USA; Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Agnel Sfeir
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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25
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Yang YX, Jin YC, Jin HQ, Liu YM, Ying MF, Jin CT, Zhao R. Astragaloside IV protects cardiomyocytes from hypoxic injury by regulating endoplasmic reticulum stress via eIF2α/CHOP signaling pathway. Pharmazie 2023; 78:196-200. [PMID: 38037218 DOI: 10.1691/ph.2023.1946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Endoplasmic reticulum stress (ER stress) is suggested to promote cardiomyocyte apoptosis and ultimately lead to ischemic injury. Inhibition of ER stress-induced apoptosis may be a therapeutic strategy for MI injury. Astragaloside-IV (AST) from Astragalus membranaceus (Fisch) Bge, was reported to have cardioprotective properties. In this study, we investigated the protective effect of AST on cardiomyocytes against hypoxia injury by regulating ER stress and inhibiting apoptosis. H9c2 cardiomyocytes were divided into three groups, normal group, hypoxia group and AST group. Cell viability was determined by CCK-8 assay. Intracellular reactive oxygen species (ROS) production was detected by DCFH-DA (2,7- dichloro-dihydrofluorescein diacetate) florescent staining. The study showed that AST treatment could significantly increase the cell viability of H9c2 cells exposed to hypoxia. Furthermore, AST could restrain cell apoptosis and decrease the production of ROS. Compared with normal group, the protein levels of Bax, caspase-3, caspase-9, GRP78, p-eIF2α, and CHOP were enhanced in the hypoxia group, whereas the protein level of Bcl-2 was dramatically reduced. Compared with hypoxia group, AST markedly inhibited the phosphorylation of eIF2α and the expression of caspase-3, caspase-9 and CHOP, and promoted the protein expression of Bcl-2. Thus, AST can inhibit the ER stress-mediated apoptosis, partly through the eIF2α/CHOP pathway suppression to inhibit ER stress.
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Affiliation(s)
- Ying-Xin Yang
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ye-Cheng Jin
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hua-Qian Jin
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yan-Mo Liu
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Miao-Fa Ying
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Cheng-Tao Jin
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Rui Zhao
- Department of Pharmacy, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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26
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Grove DJ, Levine DJ, Kearse MG. Increased levels of eIF2A inhibit translation by sequestering 40S ribosomal subunits. Nucleic Acids Res 2023; 51:9983-10000. [PMID: 37602404 PMCID: PMC10570035 DOI: 10.1093/nar/gkad683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/22/2023] Open
Abstract
eIF2A was the first eukaryotic initiator tRNA carrier discovered but its exact function has remained enigmatic. Uncharacteristic of translation initiation factors, eIF2A is reported to be non-cytosolic in multiple human cancer cell lines. Attempts to study eIF2A mechanistically have been limited by the inability to achieve high yield of soluble recombinant protein. Here, we developed a purification paradigm that yields ∼360-fold and ∼6000-fold more recombinant human eIF2A from Escherichia coli and insect cells, respectively, than previous reports. Using a mammalian in vitro translation system, we found that increased levels of recombinant human eIF2A inhibit translation of multiple reporter mRNAs, including those that are translated by cognate and near-cognate start codons, and does so prior to start codon recognition. eIF2A also inhibited translation directed by all four types of cap-independent viral IRESs, including the CrPV IGR IRES that does not require initiation factors or initiator tRNA, suggesting excess eIF2A sequesters 40S subunits. Supplementation with additional 40S subunits prevented eIF2A-mediated inhibition and pull-down assays demonstrated direct binding between recombinant eIF2A and purified 40S subunits. These data support a model that eIF2A must be kept away from the translation machinery to avoid sequestering 40S ribosomal subunits.
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Affiliation(s)
- Daisy J Grove
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel J Levine
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Michael G Kearse
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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27
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Zhang L, Zhi K, Su Y, Peng W, Meng X. Effect of eIF2α in Neuronal Injury Induced by High Glucose and the Protective Mechanism of Resveratrol. Mol Neurobiol 2023; 60:6043-6059. [PMID: 37410333 DOI: 10.1007/s12035-023-03457-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023]
Abstract
Diabetes mellitus (DM) is a type of metabolic disease characterized by chronic hyperglycemia, which can lead to different degrees of cognitive decline. Therefore, it is crucial to explore the molecular biological mechanisms of neuronal injury. In this study, we investigated the effect of high glucose on eIF2α expression and the mechanism of neuronal injury, and on this basis, the protective mechanism of resveratrol is explored. Treatment with 50 mM high glucose in cortical neurons increased the levels of eIF2α phosphorylation; the expressions of ATF4 and CHOP increased. ISRIB alleviated high glucose-induced neuronal injury by reducing eIF2α phosphorylation when neurons were pretreated with ISRIB before high glucose treatment. Compared with the high glucose-treated group, resveratrol pretreatment reduced eIF2α phosphorylation, the levels of its downstream molecules ATF4 and CHOP, and LDH release. Resveratrol reduced the level of cortical eIF2α phosphorylation and the expression of its downstream molecules in DM mice and improved the ability of spatial memory and learning in DM mice without affecting anxiety and motor performance. Meanwhile, resveratrol modulated the expression of Bcl-2 protein and also effectively decreased the DM-induced up-regulation of Bax, caspase-3, p53, p21, and p16. Taken together, these results suggested that high glucose caused neuronal injury through the eIF2α/ATF4/CHOP pathway which was inhibited by ISRIB and resveratrol. The present study indicates that eIF2α is the new target for the treatment of high glucose-induced neuronal injury, and resveratrol is a potential new medicine to treat diabetes encephalopathy.
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Affiliation(s)
- Lijing Zhang
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Kaining Zhi
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yanfang Su
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wenpeng Peng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Xianfang Meng
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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28
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Kim KK, Lee TH, Park BS, Kang D, Kim DH, Jeong B, Kim JW, Yang HR, Kim HR, Jin S, Back SH, Park JW, Kim JG, Lee BJ. Bridging Energy Need and Feeding Behavior: The Impact of eIF2α Phosphorylation in AgRP Neurons. Diabetes 2023; 72:1384-1396. [PMID: 37478284 DOI: 10.2337/db23-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023]
Abstract
Eukaryotic translation initiation factor 2α (eIF2α) is a key mediator of the endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR). In mammals, eIF2α is phosphorylated by overnutrition-induced ER stress and is related to the development of obesity. Here, we studied the function of phosphorylated eIF2α (p-eIF2α) in agouti-related peptide (AgRP) neurons using a mouse model (AgRPeIF2αA/A) with an AgRP neuron-specific substitution from Ser 51 to Ala in eIF2α, which impairs eIF2α phosphorylation in AgRP neurons. These AgRPeIF2αA/A mice had decreases in starvation-induced AgRP neuronal activity and food intake and an increased responsiveness to leptin. Intriguingly, impairment of eIF2α phosphorylation produced decreases in the starvation-induced expression of UPR and autophagy genes in AgRP neurons. Collectively, these findings suggest that eIF2α phosphorylation regulates AgRP neuronal activity by affecting intracellular responses such as the UPR and autophagy during starvation, thereby participating in the homeostatic control of whole-body energy metabolism. ARTICLE HIGHLIGHTS This study examines the impact of eukaryotic translation initiation factor 2α (eIF2α) phosphorylation, triggered by an energy deficit, on hypothalamic AgRP neurons and its subsequent influence on whole-body energy homeostasis. Impaired eIF2α phosphorylation diminishes the unfolded protein response and autophagy, both of which are crucial for energy deficit-induced activation of AgRP neurons. This study highlights the significance of eIF2α phosphorylation as a cellular marker indicating the availability of energy in AgRP neurons and as a molecular switch that regulates homeostatic feeding behavior.
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Affiliation(s)
- Kwang Kon Kim
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Tae Hwan Lee
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Byong Seo Park
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
- Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University, Incheon, Republic of Korea
| | - Dasol Kang
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Dong Hee Kim
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Bora Jeong
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Jin Woo Kim
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Hye Rim Yang
- Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University, Incheon, Republic of Korea
| | - Han Rae Kim
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, George Washington University, Washington, DC
| | - Sungho Jin
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY
| | - Sung Hoon Back
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
- Basic-Clinical Convergence Research Center, University of Ulsan, Ulsan, Republic of Korea
| | - Jeong Woo Park
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
- Basic-Clinical Convergence Research Center, University of Ulsan, Ulsan, Republic of Korea
| | - Jae Geun Kim
- Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University, Incheon, Republic of Korea
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
- Basic-Clinical Convergence Research Center, University of Ulsan, Ulsan, Republic of Korea
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29
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Wang Y, Wu D, Li D, Zhou X, Fan D, Pan J. The role of PERK-eIF2α-ATF4-CHOP pathway in sevoflurane induced neuroapoptosis and cognitive dysfunction in aged mice. Cell Signal 2023; 110:110841. [PMID: 37549858 DOI: 10.1016/j.cellsig.2023.110841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 07/24/2023] [Accepted: 08/02/2023] [Indexed: 08/09/2023]
Abstract
Postoperative cognitive dysfunction (POCD) is a common surgical complication that causes additional pain in patients and affects their quality of life. To address this problem, emerging studies have focused on the POCD. Recent studies have shown that aging and anesthetic exposure are the two major risk factors for developing POCD. However, few reports described the exact molecular mechanisms underlying POCD in elderly patients. In the previous studies, the endoplasmic reticulum (ER) stress and neuroapoptosis in the hippocampus were associated with inducing POCD; however, no further information on the related signaling pathways could be disclosed. The PERK-eIF2α-ATF4-CHOP pathway is identified as the main regulatory pathway involved in ER stress and cell apoptosis. Therefore, we assume that the occurrence of POCD induced by sevoflurane inhalation may potentially result from ER stress and neuroapoptosis in the hippocampus of aged mice mediated by the PERK-eIF2α-ATF4-CHOP pathway. In our study, we found a relationship between sevoflurane inhalation concentration and memory decline in aged mice, with a 'ceiling effect'. We have confirmed that POCD induced by sevoflurane results from ER stress and neuroapoptosis in the hippocampus of aged mice, which is regulated by the over-expression of PERK-eIF2α-ATF4-CHOP pathway. Furthermore, we also showed that the dephosphorylation inhibitor of eIF2α (salubrinal) could down-regulate PERK-eIF2α-ATF4-CHOP pathway expression to inhibit ER stress and enhance the cognitive function of aged mice. In general, our study has elucidated one of the molecular mechanisms of sevoflurane-related cognitive dysfunction in aged groups and provided new strategies for treating sevoflurane-induced POCD.
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Affiliation(s)
- Yuhao Wang
- State Key Laboratory of Oral Disease & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China; Frontier Innovation Center for Dental Medicine Plus, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China
| | - Di Wu
- State Key Laboratory of Oral Disease & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China
| | - Danni Li
- Department of Anesthesiology, Sichuan Academy of Medical Science, Sichuan Provincial People's Hospital, Chengdu 610072, PR China; School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, PR China
| | - Xueer Zhou
- State Key Laboratory of Oral Disease & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China; Frontier Innovation Center for Dental Medicine Plus, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China
| | - Dan Fan
- Department of Anesthesiology, Sichuan Academy of Medical Science, Sichuan Provincial People's Hospital, Chengdu 610072, PR China; School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, PR China.
| | - Jian Pan
- State Key Laboratory of Oral Disease & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China; Frontier Innovation Center for Dental Medicine Plus, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, PR China.
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30
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Yang SY, Liao L, Hu SY, Deng L, Andriani L, Zhang TM, Zhang YL, Ma XY, Zhang FL, Liu YY, Li DQ. ETHE1 Accelerates Triple-Negative Breast Cancer Metastasis by Activating GCN2/eIF2α/ATF4 Signaling. Int J Mol Sci 2023; 24:14566. [PMID: 37834012 PMCID: PMC10572406 DOI: 10.3390/ijms241914566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/10/2023] [Accepted: 09/12/2023] [Indexed: 10/15/2023] Open
Abstract
Triple-negative breast cancer (TNBC) is the most fatal subtype of breast cancer; however, effective treatment strategies for TNBC are lacking. Therefore, it is important to explore the mechanism of TNBC metastasis and identify its therapeutic targets. Dysregulation of ETHE1 leads to ethylmalonic encephalopathy in humans; however, the role of ETHE1 in TNBC remains elusive. Stable cell lines with ETHE1 overexpression or knockdown were constructed to explore the biological functions of ETHE1 during TNBC progression in vitro and in vivo. Mass spectrometry was used to analyze the molecular mechanism through which ETHE1 functions in TNBC progression. ETHE1 had no impact on TNBC cell proliferation and xenograft tumor growth but promoted TNBC cell migration and invasion in vitro and lung metastasis in vivo. The effect of ETHE1 on TNBC cell migratory potential was independent of its enzymatic activity. Mechanistic investigations revealed that ETHE1 interacted with eIF2α and enhanced its phosphorylation by promoting the interaction between eIF2α and GCN2. Phosphorylated eIF2α in turn upregulated the expression of ATF4, a transcriptional activator of genes involved in cell migration and tumor metastasis. Notably, inhibition of eIF2α phosphorylation through ISRIB or ATF4 knockdown partially abolished the tumor-promoting effect of ETHE1 overexpression. ETHE1 has a functional and mechanistic role in TNBC metastasis and offers a new therapeutic strategy for targeting ETHE1-propelled TNBC using ISRIB.
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Affiliation(s)
- Shao-Ying Yang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Li Liao
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Shu-Yuan Hu
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
| | - Ling Deng
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
| | - Lisa Andriani
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
| | - Tai-Mei Zhang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
| | - Yin-Ling Zhang
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
| | - Xiao-Yan Ma
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
| | - Fang-Lin Zhang
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
| | - Ying-Ying Liu
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
| | - Da-Qiang Li
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
- Shanghai Key Laboratory of Breast Cancer, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Shanghai Key Laboratory of Radiation Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
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Cardenal Peralta C, Vandroux P, Neumann-Arnold L, Panvert M, Fagart J, Seufert W, Mechulam Y, Schmitt E. Binding of human Cdc123 to eIF2γ. J Struct Biol 2023; 215:108006. [PMID: 37507029 DOI: 10.1016/j.jsb.2023.108006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/18/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
Eukaryotic initiation factor 2 (eIF2) plays a key role in protein synthesis and in its regulation. The assembly of this heterotrimeric factor is facilitated by Cdc123, a member of the ATP grasp family that binds the γ subunit of eIF2. Notably, some mutations related to MEHMO syndrome, an X-linked intellectual disability, affect Cdc123-mediated eIF2 assembly. The mechanism of action of Cdc123 is unclear and structural information for the human protein is awaited. Here, the crystallographic structure of human Cdc123 (Hs-Cdc123) bound to domain 3 of human eIF2γ (Hs-eIF2γD3) was determined. The structure shows that the domain 3 of eIF2γ is bound to domain 1 of Cdc123. In addition, the long C-terminal region of Hs-Cdc123 provides a link between the ATP and Hs-eIF2γD3 binding sites. A thermal shift assay shows that ATP is tightly bound to Cdc123 whereas the affinity of ADP is much smaller. Yeast cell viability experiments, western blot analysis and two-hybrid assays show that ATP is important for the function of Hs-Cdc123 in eIF2 assembly. These data and recent findings allow us to propose a refined model to explain the mechanism of action of Cdc123 in eIF2 assembly.
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Affiliation(s)
- Cristina Cardenal Peralta
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Paul Vandroux
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Lea Neumann-Arnold
- Department of Genetics, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Michel Panvert
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Jérôme Fagart
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Wolfgang Seufert
- Department of Genetics, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany.
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau cedex, France.
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Wek RC, Anthony TG, Staschke KA. Surviving and Adapting to Stress: Translational Control and the Integrated Stress Response. Antioxid Redox Signal 2023; 39:351-373. [PMID: 36943285 PMCID: PMC10443206 DOI: 10.1089/ars.2022.0123] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/23/2023]
Abstract
Significance: Organisms adapt to changing environments by engaging cellular stress response pathways that serve to restore proteostasis and enhance survival. A primary adaptive mechanism is the integrated stress response (ISR), which features phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2). Four eIF2α kinases respond to different stresses, enabling cells to rapidly control translation to optimize management of resources and reprogram gene expression for stress adaptation. Phosphorylation of eIF2 blocks its guanine nucleotide exchange factor, eIF2B, thus lowering the levels of eIF2 bound to GTP that is required to deliver initiator transfer RNA (tRNA) to ribosomes. While bulk messenger RNA (mRNA) translation can be sharply lowered by heightened phosphorylation of eIF2α, there are other gene transcripts whose translation is unchanged or preferentially translated. Among the preferentially translated genes is ATF4, which directs transcription of adaptive genes in the ISR. Recent Advances and Critical Issues: This review focuses on how eIF2α kinases function as first responders of stress, the mechanisms by which eIF2α phosphorylation and other stress signals regulate the exchange activity of eIF2B, and the processes by which the ISR triggers differential mRNA translation. To illustrate the synergy between stress pathways, we describe the mechanisms and functional significance of communication between the ISR and another key regulator of translation, mammalian/mechanistic target of rapamycin complex 1 (mTORC1), during acute and chronic amino acid insufficiency. Finally, we discuss the pathological conditions that stem from aberrant regulation of the ISR, as well as therapeutic strategies targeting the ISR to alleviate disease. Future Directions: Important topics for future ISR research are strategies for modulating this stress pathway in disease conditions and drug development, molecular processes for differential translation and the coordinate regulation of GCN2 and other stress pathways during physiological and pathological conditions. Antioxid. Redox Signal. 39, 351-373.
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Affiliation(s)
- Ronald C. Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
| | - Tracy G. Anthony
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Kirk A. Staschke
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
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Zhu X, Yang L, Han X, Huang C, Huang G, Wei T, Shu L, Xu J. Oxidized phospholipids facilitate calcific aortic valve disease by elevating ATF4 through the PERK/eIF2α axis. Aging (Albany NY) 2023; 15:6834-6847. [PMID: 37462732 PMCID: PMC10415544 DOI: 10.18632/aging.204875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/15/2023] [Indexed: 08/07/2023]
Abstract
In this study we sought to analyze the critical role of oxidized phospholipid (OxPL) in the progression of calcific aortic valve disease (CAVD) with the involvement of activating transcription factor 4 (ATF4). Differentially expressed genes related to CAVD were identified using bioinformatics analysis. Expression of ATF4 was examined in mouse models of aortic valve calcification (AVC) induced by the high cholesterol (HC) diet. Valvular interstitial cells (VICs) were then isolated from mouse non-calcified valve tissues, induced by osteogenic induction medium (OIM) and co-cultured with OxPAPC-stimulated macrophages. The effect of OxPLs regulating ATF4 on the macrophage polarization and osteogenic differentiation of VICs was examined with gain- and loss-of-function experiments in VICs and in vivo. In aortic valve tissues and OIM-induced VICs, ATF4 was highly expressed. ATF4 knockdown alleviated the osteogenic differentiation of VICs, as evidenced by reduced expression of bone morphogenetic protein-2 (BMP2), osteopontin (OPN), and osteocalcin. In addition, knockdown of ATF4 arrested the AVC in vivo. Meanwhile, OxPL promoted M1 polarization of macrophages and mediated osteogenic differentiation of VICs. Furthermore, OxPL up-regulated ATF4 expression through protein kinase R-like endoplasmic reticulum kinase (PERK)/eukaryotic translation initiation factor 2 subunit alpha (eIF2α) pathway. In conclusion, OxPL can potentially up-regulate the expression of ATF4, inducing macrophages polarized to M1 phenotype, osteogenic differentiation of VICs and AVC, thus accelerating the progression of CAVD.
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Affiliation(s)
- Xiaohua Zhu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Linjie Yang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Xu Han
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Chen Huang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Gongcheng Huang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Tingju Wei
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Liliang Shu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
| | - Jing Xu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, P.R. China
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Kumar A, Subramani C, Raj S, Ranjith-Kumar CT, Surjit M. Hepatitis E Virus Protease Inhibits the Activity of Eukaryotic Initiation Factor 2-Alpha Kinase 4 and Promotes Virus Survival. J Virol 2023; 97:e0034723. [PMID: 37199644 PMCID: PMC10308950 DOI: 10.1128/jvi.00347-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/02/2023] [Indexed: 05/19/2023] Open
Abstract
Multiple mechanisms exist in a cell to cope with stress. Four independent stress-sensing kinases constitute the integrated stress response machinery of the mammalian cell, and they sense the stress signals and act by phosphorylating the eukaryotic initiation factor 2α (eIF2α) to arrest cellular translation. Eukaryotic initiation factor 2 alpha kinase 4 (eIF2AK4) is one of the four kinases and is activated under conditions of amino acid starvation, UV radiation, or RNA virus infection, resulting in shutdown of global translation. An earlier study in our laboratory constructed the protein interaction network of the hepatitis E virus (HEV) and identified eIF2AK4 as a host interaction partner of the genotype 1 (g1) HEV protease (PCP). Here, we report that PCP's association with the eIF2AK4 results in inhibition of self-association and concomitant loss of kinase activity of eIF2AK4. Site-directed mutagenesis of the 53rd phenylalanine residue of PCP abolishes its interaction with the eIF2AK4. Further, a genetically engineered HEV-expressing F53A mutant PCP shows poor replication efficiency. Collectively, these data identify an additional property of the g1-HEV PCP protein, through which it helps the virus in antagonizing eIF2AK4-mediated phosphorylation of the eIF2α, thus contributing to uninterrupted synthesis of viral proteins in the infected cells. IMPORTANCE Hepatitis E virus (HEV) is a major cause of acute viral hepatitis in humans. It causes chronic infection in organ transplant patients. Although the disease is self-limiting in normal individuals, it is associated with high mortality (~30%) in pregnant women. In an earlier study, we identified the interaction between the genotype 1 HEV protease (PCP) and cellular eukaryotic initiation factor 2 alpha kinase 4 (eIF2AK4). Since eIF2AK4 is a sensor of the cellular integrated stress response machinery, we evaluated the significance of the interaction between PCP and eIF2AK4. Here, we show that PCP competitively associates with and interferes with self-association of the eIF2AK4, thereby inhibiting its kinase activity. Lack of eIF2AK4 activity prevents phosphorylation-mediated inactivation of the cellular eIF2α, which is essential for initiation of cap-dependent translation. Thus, PCP behaves as a proviral factor, promoting uninterrupted synthesis of viral proteins in infected cells, which is crucial for survival and proliferation of the virus.
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Affiliation(s)
- Amit Kumar
- Virology Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Chandru Subramani
- Virology Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Shivani Raj
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
| | - C. T. Ranjith-Kumar
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
| | - Milan Surjit
- Virology Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
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Yao M, Li G, Zhou LY, Zheng Z, Sun YL, Liu SF, Wang YJ, Cui XJ. Shikonin inhibits neuronal apoptosis via regulating endoplasmic reticulum stress in the rat model of double-level chronic cervical cord compression. Cell Biol Toxicol 2023; 39:907-928. [PMID: 35028790 DOI: 10.1007/s10565-021-09648-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/17/2021] [Indexed: 01/16/2023]
Abstract
Cervical spondylotic myelopathy (CSM) is a clinically symptomatic entity arising from the spinal cord compression by degenerative diseases. Although endoplasmic reticulum (ER) stress has been commonly observed in several neurodegenerative diseases, the relationship between ER stress and CSM remains unknown. Shikonin is known to protect PC12 by inhibiting apoptosis in vitro. This study hypothesised that ER stress was vital in neuronal apoptosis in CSM. Shikonin might inhibit such responses by regulating ER stress through the protein kinase-like ER kinase-eukaryotic translation initiation factor 2 α-subunit-C/EBP homologous protein (PERK-eIF2α-CHOP) signalling pathway. Thus, the aim of this study was evaluating the neuroprotective effect of shikonin in rats with double-level chronic cervical cord compression, as well as primary rat cortical neurons with glutamate-induced neurotoxicity. The result showed that ER stress-related upregulation of PERK-eIF2α-CHOP resulted in rat neuronal apoptosis after chronic cervical cord compression; then, shikonin promoted motor recovery and inhibited neuronal apoptosis by attenuating PERK-eIF2α-CHOP and prevented Bax translocation from cytoplasm to mitochondrion induced by CHOP of neurons in rats with chronic compression. Also, it was found that shikonin could protect rat primary cortical neuron against glutamate toxicity by regulating ER stress through the PERK-eIF2α-CHOP pathway in vitro. In conclusion, shikonin might inhibit neuronal apoptosis by regulating ER stress through attenuating the activation of PERK-eIF2α-CHOP.
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Affiliation(s)
- Min Yao
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China
| | - Gan Li
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China
| | - Long-Yun Zhou
- Rehabilitation Medicine Center, Jiangsu Provincial People's Hospital, Jiangsu, 210029, China
| | - Zhong Zheng
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China
| | - Yue-Li Sun
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China
| | - Shu-Fen Liu
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China
| | - Yong-Jun Wang
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China.
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China.
| | - Xue-Jun Cui
- Spine Disease Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, 725 South Wanping Road, Shanghai, 200032, China.
- Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China.
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Gupta R, Hinnebusch AG. Differential requirements for P stalk components in activating yeast protein kinase Gcn2 by stalled ribosomes during stress. Proc Natl Acad Sci U S A 2023; 120:e2300521120. [PMID: 37043534 PMCID: PMC10120022 DOI: 10.1073/pnas.2300521120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/13/2023] [Indexed: 04/13/2023] Open
Abstract
The General Amino Acid Control is a conserved response to amino acid starvation involving activation of protein kinase Gcn2, which phosphorylates eukaryotic initiation factor 2 (eIF2α) with attendant inhibition of global protein synthesis and increased translation of yeast transcriptional activator GCN4. Gcn2 can be activated by either amino acid starvation or conditions that stall elongating ribosomes without reducing aminoacylation of tRNA, but it is unclear whether distinct molecular mechanisms operate in these two circumstances. We identified three regimes that activate Gcn2 in yeast cells by starvation-independent (SI) ribosome-stalling: treatment with tigecycline, eliminating the sole gene encoding tRNAArgUCC, and depletion of translation termination factor eRF1. We further demonstrated requirements for the tRNA- and ribosome-binding domains of Gcn2, the positive effector proteins Gcn1/Gcn20, and the tethering of at least one of two distinct P1/P2 heterodimers to the uL10 subunit of the ribosomal P stalk, for detectable activation by SI-ribosome stalling. Remarkably, no tethered P1/P2 proteins were required for strong Gcn2 activation elicited by starvation for histidine or branched-chain amino acids isoleucine/valine. These results indicate that Gcn2 activation has different requirements for the P stalk depending on how ribosomes are stalled. We propose that accumulation of deacylated tRNAs in amino acid-starved cells can functionally substitute for the P stalk in binding to the histidyl-tRNA synthetase-like domain of Gcn2 for eIF2α kinase activation by ribosomes stalled with A sites devoid of the eEF1A∙GTP∙aminoacyl-tRNA ternary complex.
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Affiliation(s)
- Ritu Gupta
- Section on Nutrient Control of Gene Expression, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
| | - Alan G. Hinnebusch
- Section on Nutrient Control of Gene Expression, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
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Carlson KR, Georgiadis MM, Tameire F, Staschke KA, Wek RC. Activation of Gcn2 by small molecules designed to be inhibitors. J Biol Chem 2023; 299:104595. [PMID: 36898579 PMCID: PMC10124904 DOI: 10.1016/j.jbc.2023.104595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/06/2023] [Indexed: 03/10/2023] Open
Abstract
The integrated stress response (ISR) is an important mechanism by which cells confer protection against environmental stresses. Central to the ISR is a collection of related protein kinases that monitor stress conditions, such as Gcn2 (EIF2AK4) that recognizes nutrient limitations, inducing phosphorylation of eukaryotic translation initiation factor 2 (eIF2). Gcn2 phosphorylation of eIF2 lowers bulk protein synthesis, conserving energy and nutrients, coincident with preferential translation of stress-adaptive gene transcripts, such as that encoding the Atf4 transcriptional regulator. While Gcn2 is central for cell protection to nutrient stress and its depletion in humans leads to pulmonary disorders, Gcn2 can also contribute to the progression of cancers and facilitate neurological disorders during chronic stress. Consequently, specific ATP-competitive inhibitors of Gcn2 protein kinase have been developed. In this study, we report that one such Gcn2 inhibitor, Gcn2iB, can activate Gcn2, and we probe the mechanism by which this activation occurs. Low concentrations of Gcn2iB increase Gcn2 phosphorylation of eIF2 and enhance Atf4 expression and activity. Of importance, Gcn2iB can activate Gcn2 mutants devoid of functional regulatory domains or with certain kinase domain substitutions derived from Gcn2-deficient human patients. Other ATP-competitive inhibitors can also activate Gcn2, although there are differences in their mechanisms of activation. These results provide a cautionary note about the pharmacodynamics of eIF2 kinase inhibitors in therapeutic applications. Compounds designed to be kinase inhibitors that instead directly activate Gcn2, even loss of function variants, may provide tools to alleviate deficiencies in Gcn2 and other regulators of the ISR.
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Affiliation(s)
- Kenneth R Carlson
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
| | | | - Kirk A Staschke
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA.
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Feng X, Lin T, Chen D, Li Z, Yang Q, Tian H, Xiao Y, Lin M, Liang M, Guo W, Zhao P, Guo Z. Mitochondria-associated ER stress evokes immunogenic cell death through the ROS-PERK-eIF2α pathway under PTT/CDT combined therapy. Acta Biomater 2023; 160:211-224. [PMID: 36792045 DOI: 10.1016/j.actbio.2023.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/16/2023]
Abstract
Chemodynamic therapy (CDT) can effectively induce immunogenic cell death (ICD) in tumours and is thus a promising strategy for boosting the efficacy of immunotherapy. However, the mechanism by which CDT enhances ICD and lowers ICD efficiency is unknown and this restricts its clinical application. In this study, a second near-infrared (NIR-II) window irradiation-triggered hydrogen peroxide (H2O2) self-supplying nanocomposite ((Cu2Se-CaO2)@LA) was constructed. The modified lauric acid was melted by the heat energy of the NIR-II irradiation, to expose the CaO2 nanoparticles, and they then reacted with water to produce H2O2 and Ca2+. H2O2 was then converted to hydroxyl radicals by the photothermal-enhanced CDT process of the Cu2Se nanocubes. Notably, the CDT and Ca2+ overload was found to induce sequential damage to the mitochondria and endoplasmic reticulum (ER), which upregulated the PERK-mediated eIF2α phosphorylation pathway and caused subsequent ICD. NIR-II irradiation of the (Cu2Se-CaO2)@LA also increased reactive oxygen species (ROS) formation and this was sufficient to increase dendritic cell maturation, attracting cytotoxic T lymphocytes, and suppressing tumour growth in vivo. Overall, we demonstrated that an enhanced CDT strategy under NIR-II exposure and H2O2 self-supply can induce extensive ICD by inducing mitochondria-associated ER stress, which represents a highly effective and promising strategy for ICD amplification and tumour immunotherapy. STATEMENT OF SIGNIFICANCE: In this study, a second near-infrared window (NIR-II) irradiation-triggered and H2O2 self-supplying nanocomposite (named (Cu2Se-CaO2)@LA) was constructed and tested both in vitro and in vivo. These nanoparticles demonstrated promising antitumor activity as designed. Mechanistically, the nanoparticles could damage mitochondria and upregulate the PERK-mediated eIF2αphosphorylation pathway, further causing endoplasmic reticulum stress, and inducing immunogenic cell death through dendritic cell maturation and cytotoxic T lymphocyte recruitment augmented activity. This system represents a highly effective and promising strategy for enhancing tumor immunotherapy and provides new insights for future studies and design refinements.
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Affiliation(s)
- Xiaoli Feng
- Stomatological Hospital, School of Stomatology, Southern medical University, S366 Jiangnan Boulevard, Guangzhou 510280, China
| | - Tian Lin
- Nanfang Hospital, The First School of Clinical Medicine, Southern medical University, Guangzhou 510515, China
| | - Dong Chen
- Nanfang Hospital, The First School of Clinical Medicine, Southern medical University, Guangzhou 510515, China
| | - Zhiyang Li
- Department of General Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Qiuping Yang
- Department of Oncology, Guangzhou Key Laboratory of Enhanced Recovery after Abdominal Surgery, Innovation Centre for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510700, China
| | - Huiting Tian
- Department of General Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yao Xiao
- Department of Oncology, Guangzhou Key Laboratory of Enhanced Recovery after Abdominal Surgery, Innovation Centre for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510700, China
| | - Mingzhen Lin
- Department of Oncology, Guangzhou Key Laboratory of Enhanced Recovery after Abdominal Surgery, Innovation Centre for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510700, China
| | - Min Liang
- Department of Oncology, Guangzhou Key Laboratory of Enhanced Recovery after Abdominal Surgery, Innovation Centre for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510700, China.
| | - Weihong Guo
- Nanfang Hospital, The First School of Clinical Medicine, Southern medical University, Guangzhou 510515, China.
| | - Peng Zhao
- NMPA Key Laboratory for Research and Evaluation of Drug Metabolism, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University,, Guangzhou 510515, China.
| | - Zhaoze Guo
- Nanfang Hospital, The First School of Clinical Medicine, Southern medical University, Guangzhou 510515, China.
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Chen T, Xu G, Mou R, Greene GH, Liu L, Motley J, Dong X. Global translational induction during NLR-mediated immunity in plants is dynamically regulated by CDC123, an ATP-sensitive protein. Cell Host Microbe 2023; 31:334-342.e5. [PMID: 36801014 PMCID: PMC10898606 DOI: 10.1016/j.chom.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/05/2022] [Accepted: 01/23/2023] [Indexed: 02/19/2023]
Abstract
The recognition of pathogen effectors by their cognate nucleotide-binding leucine-rich repeat (NLR) receptors activates effector-triggered immunity (ETI) in plants. ETI is associated with correlated transcriptional and translational reprogramming and subsequent death of infected cells. Whether ETI-associated translation is actively regulated or passively driven by transcriptional dynamics remains unknown. In a genetic screen using a translational reporter, we identified CDC123, an ATP-grasp protein, as a key activator of ETI-associated translation and defense. During ETI, an increase in ATP concentration facilitates CDC123-mediated assembly of the eukaryotic translation initiation factor 2 (eIF2) complex. Because ATP is required for the activation of NLRs as well as the CDC123 function, we uncovered a possible mechanism by which the defense translatome is coordinately induced during NLR-mediated immunity. The conservation of the CDC123-mediated eIF2 assembly suggests its possible role in NLR-mediated immunity beyond plants.
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Affiliation(s)
- Tianyuan Chen
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - Guoyong Xu
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Rui Mou
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - George H Greene
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - Lijing Liu
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - Jonathan Motley
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - Xinnian Dong
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA.
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Kidwell A, Yadav SPS, Maier B, Zollman A, Ni K, Halim A, Janosevic D, Myslinski J, Syed F, Zeng L, Waffo AB, Banno K, Xuei X, Doud EH, Dagher PC, Hato T. Translation Rescue by Targeting Ppp1r15a through Its Upstream Open Reading Frame in Sepsis-Induced Acute Kidney Injury in a Murine Model. J Am Soc Nephrol 2023; 34:220-240. [PMID: 36283811 PMCID: PMC10103092 DOI: 10.1681/asn.2022060644] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/23/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Translation shutdown is a hallmark of late-phase, sepsis-induced kidney injury. Methods for controlling protein synthesis in the kidney are limited. Reversing translation shutdown requires dephosphorylation of the eukaryotic initiation factor 2 (eIF2) subunit eIF2 α ; this is mediated by a key regulatory molecule, protein phosphatase 1 regulatory subunit 15A (Ppp1r15a), also known as GADD34. METHODS To study protein synthesis in the kidney in a murine endotoxemia model and investigate the feasibility of translation control in vivo by boosting the protein expression of Ppp1r15a, we combined multiple tools, including ribosome profiling (Ribo-seq), proteomics, polyribosome profiling, and antisense oligonucleotides, and a newly generated Ppp1r15a knock-in mouse model and multiple mutant cell lines. RESULTS We report that translation shutdown in established sepsis-induced kidney injury is brought about by excessive eIF2 α phosphorylation and sustained by blunted expression of the counter-regulatory phosphatase Ppp1r15a. We determined the blunted Ppp1r15a expression persists because of the presence of an upstream open reading frame (uORF). Overcoming this barrier with genetic and antisense oligonucleotide approaches enabled the overexpression of Ppp1r15a, which salvaged translation and improved kidney function in an endotoxemia model. Loss of this uORF also had broad effects on the composition and phosphorylation status of the immunopeptidome-peptides associated with the MHC-that extended beyond the eIF2 α axis. CONCLUSIONS We found Ppp1r15a is translationally repressed during late-phase sepsis because of the existence of an uORF, which is a prime therapeutic candidate for this strategic rescue of translation in late-phase sepsis. The ability to accurately control translation dynamics during sepsis may offer new paths for the development of therapies at codon-level precision. PODCAST This article contains a podcast at.
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Affiliation(s)
- Ashley Kidwell
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | | | - Bernhard Maier
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amy Zollman
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Kevin Ni
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Arvin Halim
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Danielle Janosevic
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jered Myslinski
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Farooq Syed
- Department of Pediatrics and the Herman B. Wells Center, Indiana University School of Medicine, Indianapolis, Indiana
| | - Lifan Zeng
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Alain Bopda Waffo
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Kimihiko Banno
- Department of Physiology, Nara Medical University, Kashihara, Japan
| | - Xiaoling Xuei
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Emma H. Doud
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Pierre C. Dagher
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Takashi Hato
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
- Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana
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Amin PH, Carlson KR, Wek RC. An RNA stem-loop functions in conjunction with an upstream open reading frame to direct preferential translation in the integrated stress response. J Biol Chem 2023; 299:102864. [PMID: 36596357 PMCID: PMC9971878 DOI: 10.1016/j.jbc.2022.102864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 11/30/2022] [Accepted: 12/28/2022] [Indexed: 01/02/2023] Open
Abstract
In response to environmental stresses, cells invoke translational control to conserve resources and rapidly reprogram gene expression for optimal adaptation. A central mechanism for translational control involves phosphorylation of the α subunit of eIF2 (p-eIF2α), which reduces delivery of initiator tRNA to ribosomes. Because p-eIF2α is invoked by multiple protein kinases, each responding to distinct stresses, this pathway is named the integrated stress response (ISR). While p-eIF2α lowers bulk translation initiation, many stress-related mRNAs are preferentially translated. The process by which ribosomes delineate gene transcripts for preferential translation is known to involve upstream open reading frames (uORFs) embedded in the targeted mRNAs. In this study, we used polysome analyses and reporter assays to address the mechanisms directing preferential translation of human IBTKα in the ISR. The IBTKα mRNA encodes four uORFs, with only 5'-proximal uORF1 and uORF2 being translated. Of importance, the 5'-leader of IBTKα mRNA also contains a phylogenetically conserved stem-loop of moderate stability that is situated 11 nucleotides downstream of uORF2. The uORF2 is well translated and functions in combination with the stem-loop to effectively lower translation reinitiation at the IBTKα coding sequence. Upon stress-induced p-eIF2α, the uORF2/stem loop element can be bypassed to enhance IBTKα translation by a mechanism that may involve the modestly translated uORF1. Our study demonstrates that uORFs in conjunction with RNA secondary structures can be critical elements that serve as the "bar code" by which scanning ribosomes can delineate which mRNAs are preferentially translated in the ISR.
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Affiliation(s)
- Parth H Amin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Kenneth R Carlson
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Yang H, Chen T, Denoyelle S, Chen L, Fan J, Zhang Y, Halperin JA, Chorev M, Aktas BH. Role of symmetry in 3,3-diphenyl-1,3-dihydroindol-2-one derivatives as inhibitors of translation initiation. Bioorg Med Chem Lett 2023; 80:129119. [PMID: 36581302 PMCID: PMC9922553 DOI: 10.1016/j.bmcl.2022.129119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/13/2022] [Accepted: 12/23/2022] [Indexed: 12/28/2022]
Abstract
The ternary complex (eIF2·GTP·Met-tRNAiMet) and the eIF4F complex assembly are two major regulatory steps in the eukaryotic translation initiation. Inhibition of the ternary complex assembly is therefore a promising target for the development of novel anti-cancer therapeutics. Building on the finding that clotrimazole (CLT), a molecular probe that depletes intracellular Ca2+ stores and subsequently induce eIF2α phosphorylation, inhibit translation initiation, and reduce preferentially the expression of oncoproteins over "housekeeping" ones,1-3 we undertook structure activity relationship (SAR) studies that identified 3,3-diarylindoline-2-one #1181 as an interesting scaffold. Compound #1181 also induce phosphorylation of eIF2α thereby reducing the availability of the ternary complex, which leads to inhibition of translation initiation.4 Our subsequent efforts focused on understanding SAR iterative lead optimization to enhance potency and improve bioavailability. Herein, we report a complementing study focusing on heavily substituted symmetric and asymmetric 3,3-(o,m-disubstituted)diarylindoline-2-ones. These compounds were evaluated by the dual luciferase reporter ternary complex assay that recapitualates phosphorylation of eIF2α in a quantitative manner. We also evaluated all compounds by sulforhodamine B assay, which measures the overall effect of compounds on cell proliferations and/or viability.
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Affiliation(s)
- Hongwei Yang
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA.
| | - Ting Chen
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Séverine Denoyelle
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Limo Chen
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Jing Fan
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Yingzhen Zhang
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - José A Halperin
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA; Harvard Medical School, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA
| | - Michael Chorev
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA; Harvard Medical School, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA.
| | - Bertal H Aktas
- Brigham and Women's Hospital, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA; Harvard Medical School, Division of Hematology, 4 Balckfan Circle. HIM 7, Boston, MA 02115, USA.
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Lokdarshi A, von Arnim AG, Akuoko TK. Modulation of GCN2 activity under excess light stress by osmoprotectants and amino acids. Plant Signal Behav 2022; 17:2115747. [PMID: 36093942 PMCID: PMC9481134 DOI: 10.1080/15592324.2022.2115747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
The protein kinase GCN2 (General Control Nonderepressible2) and its phosphorylation target, the eukaryotic translation initiation factor (eIF)2α represent the core module of the plant's integrated stress response, a signaling pathway widely conserved in eukaryotes that can rapidly regulate translation in response to stressful conditions. Recent findings indicate that the Arabidopsis thaliana GCN2 protein operates under the command of reactive oxygen species (ROS) emanating from the chloroplast under a variety of abiotic stresses such as excess light. To get deeper insights into the mechanism of GCN2 activation under excess light, we assessed the role of amino acids in view of the classic function of GCN2 as a sensor of amino acid status. Additionally, given that osmoprotectants can counteract ROS-related stresses, we tested their ability to mitigate GCN2 activity. Our results demonstrate that certain amino acids and osmoprotectants attenuate eIF2α-phosphorylation under excess light stress to some degree. Future investigations into the biochemical mechanisms of these natural compounds on GCN2 signaling activity will provide better insights into the GCN2-eIF2α regulation.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biology, Valdosta State University, Valdosta, GA, USA
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
- UT-ORNL Graduate School of Genome Science and Technology, the University of Tennessee, Knoxville, TN, USA
| | - Teressa K Akuoko
- Department of Biology, Valdosta State University, Valdosta, GA, USA
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Castillo KD, Wu C, Ding Z, Lopez-Garcia OK, Rowlinson E, Sachs MS, Bell-Pedersen D. A circadian clock translational control mechanism targets specific mRNAs to cytoplasmic messenger ribonucleoprotein granules. Cell Rep 2022; 41:111879. [PMID: 36577368 PMCID: PMC10241597 DOI: 10.1016/j.celrep.2022.111879] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 09/13/2022] [Accepted: 12/04/2022] [Indexed: 12/29/2022] Open
Abstract
Phosphorylation of Neurospora crassa eukaryotic initiation factor 2 α (eIF2α), a conserved translation initiation factor, is clock controlled. To determine the impact of rhythmic eIF2α phosphorylation on translation, we performed temporal ribosome profiling and RNA sequencing (RNA-seq) in wild-type (WT), clock mutant Δfrq, eIF2α kinase mutant Δcpc-3, and constitutively active cpc-3c cells. About 14% of mRNAs are rhythmically translated in WT cells, and translation rhythms for ∼30% of these mRNAs, which we named circadian translation-initiation-controlled genes (cTICs), are dependent on the clock and CPC-3. Most cTICs are expressed from arrhythmic mRNAs and contain a P-body (PB) localization motif in their 5' leader sequence. Deletion of SNR-1, a component of cytoplasmic messenger ribonucleoprotein granules (cmRNPgs) that include PBs and stress granules (SGs), and the PB motif on one of the cTIC mRNAs, zip-1, significantly alters zip-1 rhythmic translation. These results reveal that the clock regulates rhythmic translation of specific mRNAs through rhythmic eIF2α activity and cmRNPg metabolism.
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Affiliation(s)
- Kathrina D Castillo
- Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843, USA; Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Cheng Wu
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Zhaolan Ding
- Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843, USA; Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | | | - Emma Rowlinson
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Matthew S Sachs
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Deborah Bell-Pedersen
- Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843, USA; Department of Biology, Texas A&M University, College Station, TX 77843, USA.
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Zhong H, Fan S, Du Y, Zhang Y, Zhang A, Jiang D, Han S, Wan B, Zhang G. African Swine Fever Virus MGF110-7L Induces Host Cell Translation Suppression and Stress Granule Formation by Activating the PERK/PKR-eIF2α Pathway. Microbiol Spectr 2022; 10:e0328222. [PMID: 36377947 PMCID: PMC9769596 DOI: 10.1128/spectrum.03282-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/30/2022] [Indexed: 11/16/2022] Open
Abstract
African swine fever (ASF) is a highly contagious and often lethal disease of pigs caused by ASF virus (ASFV) and recognized as the biggest killer in global swine industry. Despite exhibiting incredible self-sufficiency, ASFV remains unconditionally dependent on the host translation machinery for its mRNA translation. However, less is yet known regarding how ASFV-encoded proteins regulate host translation machinery in infected cells. Here, we examined how ASFV interacts with the eukaryotic initiation factor 2α (eIF2α) signaling axis, which directs host translation control and adaptation to cellular stress. We found that ASFV MGF110-7L, a previously uncharacterized member of the multigene family 110, remarkably enhanced the phosphorylation level of eIF2α. In porcine alveolar macrophage 3D4/21 and porcine kidney-15 cells, MGF110-7L triggered eIF2α signaling and the integrated stress response, resulting in the suppression of host translation and the formation of stress granules (SGs). Mechanistically, MGF110-7L-induced phosphorylation of eIF2α was mediated via protein kinase R (PKR) and PKR-like endoplasmic reticulum (ER) kinase (PERK), and this process was essential for host translation repression and SG formation. Notably, our subsequent analyses confirmed that MGF110-7L was overwhelmingly retained in the ER and caused a specific reorganization of the secretory pathway. Further proteomic analyses and biochemical experiments revealed that MGF110-7L could trigger ER stress and activate the unfolded protein response, thus contributing to eIF2α phosphorylation and translation reprogramming. Overall, our study both identifies a novel mechanism by which ASFV MGF110-7L subverts the host protein synthesis machinery and provides further insights into the translation regulation that occurs during ASFV infection. IMPORTANCE African swine fever (ASF) has become a socioeconomic burden and a threat to food security and biodiversity, but no commercial vaccines or antivirals are available currently. Understanding the viral strategies to subvert the host translation machinery during ASF virus (ASFV) infection could potentially lead to new vaccines and antiviral therapies. In this study, we dissected how ASFV MGF110-7L interacts with the eIF2α signaling axis controlling translational reprogramming, and we addressed the role of MGF110-7L in induction of cellular stress responses, eIF2α phosphorylation, translation suppression, and stress granule formation. These results define several molecular interfaces by which ASFV MGF110-7L subverts host cell translation, which may guide research on antiviral strategies and dissection of ASFV pathogenesis.
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Affiliation(s)
- Han Zhong
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Shuai Fan
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Yongkun Du
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- Henan Engineering Laboratory of Animal Biological Products, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Yuhang Zhang
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Angke Zhang
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Dawei Jiang
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- Henan Engineering Laboratory of Animal Biological Products, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Shichong Han
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Bo Wan
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- Henan Engineering Laboratory of Animal Biological Products, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
| | - Gaiping Zhang
- International Joint Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, People’s Republic of China
- Longhu Laboratory, Zhengzhou, Henan, People’s Republic of China
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Zhang M, Zheng Y, Li X, Wu H, Liu P, Zhang K, Shi Z, Lv M, Wang F, Tang X. Tong-Xie-Yao-Fang alleviates diarrhea-predominant irritable bowel syndrome in rats via the GCN2/PERK-eIF2α-ATF4 signaling pathway. Phytomedicine 2022; 107:154350. [PMID: 36194974 DOI: 10.1016/j.phymed.2022.154350] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 07/01/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common functional gastrointestinal disease. Tong-Xie-Yao-Fang (TXYF), the traditional Chinese herbal medicine prescription, is a classic and effective prescription for the treatment of IBS-D, but its mechanism of action is not fully clarified. OBJECTIVE To evaluate the efficacy of TXYF in the treatment of IBS-D and to explore its potential mechanism of action. METHODS Changes in the serum levels of 50 free amino acids were targeted for detection by high-performance liquid chromatography (HPLC), and the expression of glucose-regulated protein 78 (GRP78), general control nonderepressible 2 (GCN2), and endoplasmic reticulum-resident kinase (PERK) was detected by immunohistochemistry examinations in healthy volunteers and IBS-D patients. The IBS-D rat was constructed by the three-factor superposition method of neonatal maternal separation, 2,4,6-trinitrobenzene sulfonic acid enema, and chronic unpredictable stress stimulation. The treatment effect of TXYF on IBS-D rats was observed by recording the body weight, grasp force, fecal water content (FWC), and abdominal withdrawal reflex (AWR) of rats before and after treatment. The effects of GCN2/PERK-eukaryotic initiation factor-2 (eIF2α) -activating transcription Factor 4 (ATF4) pathway proteins and gene expression were analyzed by western blotting, reverse transcription-polymerase chain reaction (RT-qPCR), and immunohistochemistry evaluations. RESULTS Compared with healthy volunteers, IBS-D patients exhibited lower levels of cysteine, γ-aminoacetic acid (GABA), homoproline, and lysine, and immunohistochemistry showed strong activation of GRP78, a marker of endoplasmic reticulum stress. Differential expression of GCN2 and PERK proteins was detected in IBS-D patients and rat colons. In the IBS-D rats, TXYF improved the body weight and grasp force, reduced the FWC, and improved the AWR score. TXYF increased the levels of p-GCN2 and GCN2 and reduced the levels of GRP78, p-PERK, PERK, p-eIF2α, and eIF2α, thereby affecting the expression of the apoptosis-related transcription factors ATF4, CHOP, Caspase-3, and Bcl-2. CONCLUSION Our study showed that TXYF improved IBS-D by inhibiting apoptosis. The anti-apoptosis effects were potentially mediated by regulating the GCN2/PERK-eIF2a-ATF4 signaling pathway.
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Affiliation(s)
- Min Zhang
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yijun Zheng
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xia Li
- Beijing University of Chinese Medicine, Beijing, China
| | - Haomeng Wu
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Ping Liu
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kunli Zhang
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhongfei Shi
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Mi Lv
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Fengyun Wang
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China.
| | - Xudong Tang
- China Academy of Chinese Medical Sciences, Beijing, China.
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Feng Y, Han Z, Jiang W, Shen H, Yu Y, Zhou N, Huang X. Promotion of osteogenesis in BMSC under hypoxia by ATF4 via the PERK-eIF2α signaling pathway. In Vitro Cell Dev Biol Anim 2022; 58:886-897. [PMID: 36378269 DOI: 10.1007/s11626-022-00732-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/25/2022] [Indexed: 11/16/2022]
Abstract
Mandibular distraction osteogenesis (MDO) is an endogenous tissue engineering technology in which bone marrow mesenchymal stem cells (BMSC) play a key role in MDO-related osteogenesis. Activating transcription factor 4 (ATF4) is involved in osteogenesis through activation of PERK (Protein kinase R-like endoplasmic reticulum kinase) in endoplasmic reticulum stress (ERS) condition under hypoxia. However, the specific role of ATF4 in MDO with BMSC remains unknown. The aim of this study was to explore the effects of ATF4 in MDO with BMSC under hypoxia. Briefly, canine BMSCs were cultured in a hypoxic chamber, and effects of hypoxia were evaluated using cell migration assay and Alizarin Red S staining. Expression levels of protein kinase R-like endoplasmic reticulum kinase, eukaryotic translation initiation factor 2α, ATF4, osteocalcin, and bone sialoprotein were evaluated using quantitative polymerase chain reaction and western blotting. BMSCs were transduced with the ATF4-small interfering RNA lentivirus. The effects were evaluated using all the aforementioned experiments. The results showed that hypoxia promoted migration, osteoblast differentiation, and ATF4 expression in BMSC. ATF4 knockdown in BMSC significantly inhibited migration and osteoblast differentiation abilities, while hypoxia reversed these effects to some extent. In addition, the molecular mechanism partly depended on the ERS signaling pathway, with ATF4 as the key factor. In summary, we presented a novel mechanism of ATF4-mediated regulation of BMSC under hypoxia.
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Affiliation(s)
- Yuan Feng
- Guangxi Medical University, Nanning, People's Republic of China
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China
| | - Zhiqi Han
- Guangxi Medical University, Nanning, People's Republic of China
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China
| | - Weidong Jiang
- Guangxi Medical University, Nanning, People's Republic of China
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China
| | - Huijuan Shen
- Guangxi Medical University, Nanning, People's Republic of China
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China
| | - Yangyang Yu
- Guangxi Medical University, Nanning, People's Republic of China
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China
| | - Nuo Zhou
- Guangxi Medical University, Nanning, People's Republic of China.
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China.
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China.
| | - Xuanping Huang
- Guangxi Medical University, Nanning, People's Republic of China.
- Department of Oral and Maxillofacial Surgery, College of Stomatology, Hospital of Stomatology, Guangxi Medical University, 10 Shuangyong Road, Nanning, Guangxi, 530021, People's Republic of China.
- Guangxi Key Laboratory of Oral and Maxillofacial Rehabilitation and Reconstruction, Guangxi Key Laboratory of Oral and Maxillofacial Surgery Disease Treatment, Guangxi Clinical Research Center for Craniofacial Deformity, Nanning, People's Republic of China.
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48
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Zhu S, Nguyen A, Pang J, Zhao J, Chen Z, Liang Z, Gu Y, Huynh H, Bao Y, Lee S, Kluger Y, Ouyang K, Evans SM, Fang X. Mitochondrial Stress Induces an HRI-eIF2α Pathway Protective for Cardiomyopathy. Circulation 2022; 146:1028-1031. [PMID: 36154620 PMCID: PMC9523491 DOI: 10.1161/circulationaha.122.059594] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Siting Zhu
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Anh Nguyen
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jing Pang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jun Zhao
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Ze’e Chen
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Zhengyu Liang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Helen Huynh
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yutong Bao
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Sharon Lee
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yuval Kluger
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Kunfu Ouyang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Sylvia M Evans
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Pharmacology, University of California San Diego, La Jolla, California, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
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49
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Feng Y, Yuan H, Wang W, Xu Y, Zhang J, Xu H, Fu F. Co-exposure to polystyrene microplastics and lead aggravated ovarian toxicity in female mice via the PERK/eIF2α signaling pathway. Ecotoxicol Environ Saf 2022; 243:113966. [PMID: 35981484 DOI: 10.1016/j.ecoenv.2022.113966] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/06/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
Generally, individual microplastics (MPs) or lead (Pb) exposure could initiate ovarian toxicity. However, their combined effects on the ovary and its mechanism in mammals remained unclear. Female C57BL/6 mice were used in this study to investigate the combined ovarian toxicity of polystyrene MPs (PS-MPs, 0.1 mg/d/mouse) and Pb (1 g/L) for 28 days. Results showed that co-exposure to PS-MPs and Pb increased the accumulation of Pb in ovaries, the histopathological damage in ovaries and uterus, the serum malondialdehyde levels and decreased serum superoxide dismutase and sex hormone levels significantly when compared with single PS-MPs and Pb exposure. These observations indicated that co-exposure exerted more severe toxicity to mouse ovaries and uterus. Furthermore, co-exposure to PS-MPs and Pb caused endoplasmic reticulum (ER) stress by activating the PERK/eIF2α signaling pathway in the ovary, which resulted in apoptosis. However, the oxidative and ovarian damage were alleviated, and the mRNA levels of genes related to the PERK/eIF2α signaling pathway were down-regulated to levels of the control mice in the PS-MPs and Pb co-exposed mice administered with ER stress inhibitor (Salubrinal, Sal) or the antioxidant (N-acetyl-cysteine, NAC). In conclusion, our findings suggested that the combination of PS-MPs and Pb aggravated ovarian toxicity in mice by inducing oxidative stress and activating the PERK/eIF2α signaling pathway, thereby providing a basis for future studies into the combined toxic mechanism of PS-MPs and Pb in mammals.
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Affiliation(s)
- Yueying Feng
- The Second Affiliated Hospital of Nanchang University, Nanchang University, Nanchang 330000, China; State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Hongbin Yuan
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Wanzhen Wang
- The Second Affiliated Hospital of Nanchang University, Nanchang University, Nanchang 330000, China; State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Yuanyuan Xu
- The Second Affiliated Hospital of Nanchang University, Nanchang University, Nanchang 330000, China
| | - Jinfeng Zhang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
| | - Hengyi Xu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
| | - Fen Fu
- The Second Affiliated Hospital of Nanchang University, Nanchang University, Nanchang 330000, China.
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50
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Green KM, Miller SL, Malik I, Todd PK. Non-canonical initiation factors modulate repeat-associated non-AUG translation. Hum Mol Genet 2022; 31:2521-2534. [PMID: 35220421 PMCID: PMC9618161 DOI: 10.1093/hmg/ddac021] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/28/2021] [Accepted: 01/14/2022] [Indexed: 11/14/2022] Open
Abstract
Repeat-associated non-AUG (RAN) translation of expanded repeat-mutation mRNA produces toxic peptides in neurons of patients suffering from neurodegenerative diseases. Recent findings indicate that RAN translation in diverse model systems is not inhibited by cellular stressors that impair global translation through phosphorylation of the alpha subunit of eIF2, the essential eukaryotic translation initiation factor that brings the initiator tRNA to the 40S ribosome. Using in vitro, cell-based and Drosophila models, we examined the role of alternative ternary complex factors that may function in place of eIF2, including eIF2A, eIF2D, DENR and MCTS1. Among these factors, DENR knockdown had the greatest inhibitory effect on RAN translation of expanded GGGGCC and CGG repeat reporters and its reduction improved the survival of Drosophila expressing expanded GGGGCC repeats. Taken together, these data support a role for alternative initiation factors in RAN translation and suggest these may serve as novel therapeutic targets in neurodegenerative disease.
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Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Shannon L Miller
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
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