1
|
Ernst R, Renne MF, Jain A, von der Malsburg A. Endoplasmic Reticulum Membrane Homeostasis and the Unfolded Protein Response. Cold Spring Harb Perspect Biol 2024; 16:a041400. [PMID: 38253414 PMCID: PMC11293554 DOI: 10.1101/cshperspect.a041400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The endoplasmic reticulum (ER) is the key organelle for membrane biogenesis. Most lipids are synthesized in the ER, and most membrane proteins are first inserted into the ER membrane before they are transported to their target organelle. The composition and properties of the ER membrane must be carefully controlled to provide a suitable environment for the insertion and folding of membrane proteins. The unfolded protein response (UPR) is a powerful signaling pathway that balances protein and lipid production in the ER. Here, we summarize our current knowledge of how aberrant compositions of the ER membrane, referred to as lipid bilayer stress, trigger the UPR.
Collapse
Affiliation(s)
- Robert Ernst
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Mike F Renne
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Aamna Jain
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Alexander von der Malsburg
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| |
Collapse
|
2
|
Taskinen JH, Ruhanen H, Matysik S, Käkelä R, Olkkonen VM. Global effects of pharmacologic inhibition of OSBP in human umbilical vein endothelial cells. Steroids 2022; 185:109053. [PMID: 35623602 DOI: 10.1016/j.steroids.2022.109053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/14/2022] [Accepted: 05/23/2022] [Indexed: 11/26/2022]
Abstract
Oxysterol-binding protein (OSBP) is a cholesterol/PI4P exchanger at contacts of the endoplasmic reticulum (ER) with trans-Golgi network (TGN) and endosomes. Several central endothelial cell (EC) functions depend on adequate cholesterol distribution in cellular membranes. Here we elucidated the effects of pharmacologic OSBP inhibition on the lipidome and transcriptome of human umbilical vein endothelial cells (HUVECs). OSBP was inhibited for 24 h with 25 nM Schweinfurthin G (SWG) or Orsaponin (OSW-1), followed by analyses of cellular cholesterol, 27-hydroxy-cholesterol, and triacylglycerol concentration, phosphatidylserine synthesis rate, the lipidome, as well as lipid droplet staining and western analysis of OSBP protein. Next-generation RNA sequencing of the SWG-treated and control HUVECs and angiogenesis assays were performed. Protein-normalized lipidomes of the inhibitor-treated cells revealed decreases in glycerophospholipids, the most pronounced effect being on phosphatidylserines and the rate of their synthesis, as well as increases in cholesteryl esters, triacylglycerols and lipid droplet number. Transcriptome analysis of SWG-treated cells suggested ER stress responses apparently caused by disturbed cholesterol exit from the ER, as indicated by suppression of cholesterol biosynthetic genes. OSBP was associated with the TGN in the absence of inhibitors and disappeared therefrom in inhibitor-treated cells in a time-dependent manner, coinciding with OSBP reduction on western blots. Prolonged treatment with SWG or OSW-1 inhibited angiogenesis in vitro. To conclude, inhibition of OSBP in primary endothelial cells induced multiple effects on the lipidome, transcriptome changes suggesting ER stress, and disruption of in vitro angiogenic capacity. Thus, OSBP is a crucial regulator of EC lipid homeostasis and angiogenic capacity.
Collapse
Affiliation(s)
- Juuso H Taskinen
- Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290 Helsinki, Finland.
| | - Hanna Ruhanen
- Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute of Life Science (HiLIFE) and Biocenter Finland, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 1, PO BOX 65, 00014 University of Helsinki, Finland.
| | - Silke Matysik
- Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
| | - Reijo Käkelä
- Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute of Life Science (HiLIFE) and Biocenter Finland, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 1, PO BOX 65, 00014 University of Helsinki, Finland.
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290 Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Haartmaninkatu 8, 00290 Helsinki, Finland.
| |
Collapse
|
3
|
Guzikowski AR, Harvey AT, Zhang J, Zhu S, Begovich K, Cohn MH, Wilhelm JE, Zid BM. Differential translation elongation directs protein synthesis in response to acute glucose deprivation in yeast. RNA Biol 2022; 19:636-649. [PMID: 35491906 PMCID: PMC9067459 DOI: 10.1080/15476286.2022.2065784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Protein synthesis is energetically expensive and its rate is influenced by factors such as cell type and environment. Suppression of translation is a canonical response to stressful changes in the cellular environment. In particular, inhibition of the initiation step of translation has been highlighted as the key control step in stress-induced translational suppression as mechanisms that quickly suppress initiation are well-conserved. However, cells have evolved complex regulatory means to control translation apart from initiation. Here, we examine the role of the elongation step of translation in yeast subjected to acute glucose deprivation. The use of ribosome profiling and in vivo reporter assays demonstrated elongation rates slow progressively following glucose removal. We observed that ribosome distribution broadly shifts towards the downstream ends of transcripts after both acute and gradual glucose deprivation but not in response to other stressors. Additionally, on assessed mRNAs, a correlation existed between ribosome occupancy and protein production pre-stress but was lost after stress. These results indicate that stress-induced elongation regulation causes ribosomes to slow down and build up on a considerable proportion of the transcriptome in response to glucose withdrawal. Finally, we report ribosomes that built up along transcripts are competent to resume elongation and complete protein synthesis after readdition of glucose to starved cells. This suggests that yeast has evolved mechanisms to slow translation elongation in response to glucose starvation which do not preclude continuation of protein production from those ribosomes, thereby averting a need for new initiation events to take place to synthesize proteins. Abbreviations: AUG: start codon, bp: base pair(s), CDS: coding sequence, CHX: cycloheximide, eEF2: eukaryotic elongation factor 2, LTM: lactimidomycin, nt: nucleotide, PGK1: 3-phosphoglycerate kinase, ribosomal biogenesis: ribi, RO: ribosome occupancy, RPF: ribosome protected fragment, TE: translational efficiency
Collapse
Affiliation(s)
- Anna R. Guzikowski
- Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Alex T. Harvey
- Department of Chemistry & Biochemistry, University of California, San Diego, CA, USA
| | - Jingxiao Zhang
- Department of Chemistry & Biochemistry, University of California, San Diego, CA, USA
| | - Shihui Zhu
- Department of Chemistry & Biochemistry, University of California, San Diego, CA, USA
| | - Kyle Begovich
- Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Molly H. Cohn
- Department of Chemistry & Biochemistry, University of California, San Diego, CA, USA
| | - James E. Wilhelm
- Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Brian M. Zid
- Department of Chemistry & Biochemistry, University of California, San Diego, CA, USA
| |
Collapse
|
4
|
Väth K, Mattes C, Reinhard J, Covino R, Stumpf H, Hummer G, Ernst R. Cysteine cross-linking in native membranes establishes the transmembrane architecture of Ire1. J Cell Biol 2021; 220:212449. [PMID: 34196665 PMCID: PMC8256922 DOI: 10.1083/jcb.202011078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 04/28/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023] Open
Abstract
The ER is a key organelle of membrane biogenesis and crucial for the folding of both membrane and secretory proteins. Sensors of the unfolded protein response (UPR) monitor the unfolded protein load in the ER and convey effector functions for maintaining ER homeostasis. Aberrant compositions of the ER membrane, referred to as lipid bilayer stress, are equally potent activators of the UPR. How the distinct signals from lipid bilayer stress and unfolded proteins are processed by the conserved UPR transducer Ire1 remains unknown. Here, we have generated a functional, cysteine-less variant of Ire1 and performed systematic cysteine cross-linking experiments in native membranes to establish its transmembrane architecture in signaling-active clusters. We show that the transmembrane helices of two neighboring Ire1 molecules adopt an X-shaped configuration independent of the primary cause for ER stress. This suggests that different forms of stress converge in a common, signaling-active transmembrane architecture of Ire1.
Collapse
Affiliation(s)
- Kristina Väth
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany.,Preclinical Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg, Germany
| | - Carsten Mattes
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany.,Preclinical Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg, Germany
| | - John Reinhard
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany.,Preclinical Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg, Germany
| | - Roberto Covino
- Frankfurt Institute of Advanced Sciences, Goethe-University, Frankfurt, Germany
| | - Heike Stumpf
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany.,Preclinical Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany.,Institute of Biophysics, Goethe-University, Frankfurt, Germany
| | - Robert Ernst
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany.,Preclinical Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg, Germany
| |
Collapse
|
5
|
Beak SH, Baik M. Comparison of transcriptome between high- and low-marbling fineness in longissimus thoracis muscle of Korean cattle. Anim Biosci 2021; 35:196-203. [PMID: 34293845 PMCID: PMC8738949 DOI: 10.5713/ab.21.0150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/11/2021] [Indexed: 11/27/2022] Open
Abstract
Objective This study compared differentially expressed genes (DEGs) between groups with high and low numbers of fine marbling particles (NFMP) in the longissimus thoracis muscle (LT) of Korean cattle to understand the molecular events associated with fine marbling particle formation. Methods The size and distribution of marbling particles in the LT were assessed with a computer image analysis method. Based on the NFMP, 10 LT samples were selected and assigned to either high- (n = 5) or low- (n = 5) NFMP groups. Using RNA sequencing, LT transcriptomic profiles were compared between the high- and low-NFMP groups. DEGs were selected at p<0.05 and |fold change| >2 and subjected to functional annotation. Results In total, 328 DEGs were identified, with 207 up-regulated and 121 down-regulated genes in the high-NFMP group. Pathway analysis of these DEGs revealed five significant (p<0.05) Kyoto encyclopedia of genes and genomes pathways; the significant terms included endocytosis (p = 0.023), protein processing in endoplasmic reticulum (p = 0.019), and adipocytokine signaling pathway (p = 0.024), which are thought to regulate adipocyte hypertrophy and hyperplasia. The expression of sirtuin4 (p<0.001) and insulin receptor substrate 2 (p = 0.043), which are associated with glucose uptake and adipocyte differentiation, was higher in the high-NFMP group than in the low-NFMP group. Conclusion Transcriptome differences between the high- and low-NFMP groups suggest that pathways regulating adipocyte hyperplasia and hypertrophy are involved in the marbling fineness of the LT.
Collapse
Affiliation(s)
- Seok-Hyeon Beak
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 08826, Korea
| | - Myunggi Baik
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Science, Seoul National University, Seoul 08826, Korea.,Institue of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Korea
| |
Collapse
|
6
|
Le QG, Kimata Y. Multiple Ways for Stress Sensing and Regulation of the Endoplasmic Reticulum-stress Sensors. Cell Struct Funct 2021; 46:37-49. [PMID: 33775971 PMCID: PMC10511038 DOI: 10.1247/csf.21015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 03/11/2021] [Indexed: 11/11/2022] Open
Abstract
Dysfunction of the endoplasmic reticulum (ER), so-called ER stress, is accompanied with accumulation of unfolded proteins in the ER. Eukaryotic cells commonly have an ER-located transmembrane protein, Ire1, which triggers cellular protective events against ER stress. In animal cells, PERK and ATF6 also initiate the ER-stress response. As a common strategy to control the activity of these ER-stress sensors, an ER-resident molecular chaperone, BiP, serves as their negative regulator, and dissociates from them in response to ER stress. Although it sounds reasonable that unfolded proteins and Ire1 compete for BiP association, some publications argue against this competition model. Moreover, yeast Ire1 (and possibly also the mammalian major Ire1 paralogue IRE1α) directly detects ER-accumulated unfolded proteins, and subsequently oligomerizes for its further activation. Apart from protein misfolding, the saturation of membrane phospholipids is another outcome of ER-stressing stimuli, which is sensed by the transmembrane domain of Ire1. This review describes the canonical and up-to-date insights concerning stress-sensing and regulatory mechanisms of yeast Ire1 and metazoan ER-stress sensors.Key words: endoplasmic reticulum, stress, unfolded protein response, molecular chaperone.
Collapse
Affiliation(s)
- Quynh Giang Le
- Institute of Biomedicine and Pharmacy, Vietnam Military Medical University, 222 Phung Hung, Ha Dong, Ha Noi, Vietnam
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet road, Cau Giay, Ha Noi, Vietnam
| | - Yukio Kimata
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| |
Collapse
|
7
|
Human Cytomegalovirus Uses a Host Stress Response To Balance the Elongation of Saturated/Monounsaturated and Polyunsaturated Very-Long-Chain Fatty Acids. mBio 2021; 12:mBio.00167-21. [PMID: 33947752 PMCID: PMC8262922 DOI: 10.1128/mbio.00167-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Stress and virus infection regulate lipid metabolism. Human cytomegalovirus (HCMV) infection induces fatty acid (FA) elongation and increases the abundance of lipids with very-long-chain FA (VLCFA) tails. While reprogramming of metabolism can be stress related, the role of stress in HCMV reprogramming of lipid metabolism is poorly understood. In this study, we engineered cells to knock out protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) in the ER stress pathway and measured lipid changes using lipidomics to determine if PERK is needed for lipid changes associated with HCMV infection. In HCMV-infected cells, PERK promotes increases in the levels of phospholipids with saturated FA (SFA) and monounsaturated FA (MUFA) VLCFA tails. Further, PERK enhances FA elongase 7 (ELOVL7) protein levels, which elongates SFA and MUFA VLCFAs. Additionally, we found that increases in the elongation of polyunsaturated fatty acids (PUFAs) associated with HCMV infection were independent of PERK and that lipids with PUFA tails accumulated in HCMV-infected PERK knockout cells. Additionally, the protein levels of ELOVL5, which elongates PUFAs, are increased by HCMV infection through a PERK-independent mechanism. These observations show that PERK differentially regulates ELOVL7 and ELOVL5, creating a balance between the synthesis of lipids with SFA/MUFA tails and PUFA tails. Additionally, we found that PERK was necessary for virus replication and the infectivity of released viral progeny. Overall, our findings indicate that PERK—and, more broadly, ER stress—may be necessary for the membrane biogenesis needed to generate infectious HCMV virions.
Collapse
|
8
|
Xu J, Taubert S. Beyond Proteostasis: Lipid Metabolism as a New Player in ER Homeostasis. Metabolites 2021; 11:52. [PMID: 33466824 PMCID: PMC7830277 DOI: 10.3390/metabo11010052] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/04/2021] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
Biological membranes are not only essential barriers that separate cellular and subcellular structures, but also perform other critical functions such as the initiation and propagation of intra- and intercellular signals. Each membrane-delineated organelle has a tightly regulated and custom-made membrane lipid composition that is critical for its normal function. The endoplasmic reticulum (ER) consists of a dynamic membrane network that is required for the synthesis and modification of proteins and lipids. The accumulation of unfolded proteins in the ER lumen activates an adaptive stress response known as the unfolded protein response (UPR-ER). Interestingly, recent findings show that lipid perturbation is also a direct activator of the UPR-ER, independent of protein misfolding. Here, we review proteostasis-independent UPR-ER activation in the genetically tractable model organism Caenorhabditis elegans. We review the current knowledge on the membrane lipid composition of the ER, its impact on organelle function and UPR-ER activation, and its potential role in human metabolic diseases. Further, we summarize the bi-directional interplay between lipid metabolism and the UPR-ER. We discuss recent progress identifying the different respective mechanisms by which disturbed proteostasis and lipid bilayer stress activate the UPR-ER. Finally, we consider how genetic and metabolic disturbances may disrupt ER homeostasis and activate the UPR and discuss how using -omics-type analyses will lead to more comprehensive insights into these processes.
Collapse
Affiliation(s)
- Jiaming Xu
- Graduate Program in Cell and Developmental Biology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Healthy Starts Theme, British Columbia Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Stefan Taubert
- Graduate Program in Cell and Developmental Biology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Healthy Starts Theme, British Columbia Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| |
Collapse
|
9
|
Hamid SM, Citir M, Terzi EM, Cimen I, Yildirim Z, Dogan AE, Kocaturk B, Onat UI, Arditi M, Weber C, Traynor-Kaplan A, Schultz C, Erbay E. Inositol-requiring enzyme-1 regulates phosphoinositide signaling lipids and macrophage growth. EMBO Rep 2020; 21:e51462. [PMID: 33140520 DOI: 10.15252/embr.202051462] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/19/2020] [Accepted: 09/22/2020] [Indexed: 12/25/2022] Open
Abstract
The ER-bound kinase/endoribonuclease (RNase), inositol-requiring enzyme-1 (IRE1), regulates the phylogenetically most conserved arm of the unfolded protein response (UPR). However, the complex biology and pathology regulated by mammalian IRE1 cannot be fully explained by IRE1's one known, specific RNA target, X box-binding protein-1 (XBP1) or the RNA substrates of IRE1-dependent RNA degradation (RIDD) activity. Investigating other specific substrates of IRE1 kinase and RNase activities may illuminate how it performs these diverse functions in mammalian cells. We report that macrophage IRE1 plays an unprecedented role in regulating phosphatidylinositide-derived signaling lipid metabolites and has profound impact on the downstream signaling mediated by the mammalian target of rapamycin (mTOR). This cross-talk between UPR and mTOR pathways occurs through the unconventional maturation of microRNA (miR) 2137 by IRE1's RNase activity. Furthermore, phosphatidylinositol (3,4,5) phosphate (PI(3,4,5)P3 ) 5-phosphatase-2 (INPPL1) is a direct target of miR-2137, which controls PI(3,4,5)P3 levels in macrophages. The modulation of cellular PI(3,4,5)P3 /PIP2 ratio and anabolic mTOR signaling by the IRE1-induced miR-2137 demonstrates how the ER can provide a critical input into cell growth decisions.
Collapse
Affiliation(s)
| | - Mevlut Citir
- The Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Erdem Murat Terzi
- Department of Pathology, Laura & Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY, USA
| | - Ismail Cimen
- Institute for Cardiovascular Prevention, LMU Munich, German Cardiovascular Research Centre, partner site Munich Heart Alliance Munich, Munich, Germany
| | - Zehra Yildirim
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.,National Nanotechnology Center, Bilkent University, Ankara, Turkey
| | - Asli Ekin Dogan
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.,National Nanotechnology Center, Bilkent University, Ankara, Turkey
| | - Begum Kocaturk
- Department of Pediatrics and Medicine, Division of Infectious Diseases and Immunology, and Infectious and Immunologic Diseases Research Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Umut Inci Onat
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.,National Nanotechnology Center, Bilkent University, Ankara, Turkey
| | - Moshe Arditi
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Pediatrics and Medicine, Division of Infectious Diseases and Immunology, and Infectious and Immunologic Diseases Research Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Christian Weber
- Institute for Cardiovascular Prevention, LMU Munich, German Cardiovascular Research Centre, partner site Munich Heart Alliance Munich, Munich, Germany.,Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Alexis Traynor-Kaplan
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.,ATK Innovation, Analytics and Discovery, North Bend, WA, USA
| | - Carsten Schultz
- The Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Ebru Erbay
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| |
Collapse
|
10
|
Zubieta MP, Gerhardt JA, Rubio MV, Terrasan CRF, Persinoti GF, Antoniel EP, Contesini FJ, Prade RA, Damasio A. Improvement of homologous GH10 xylanase production by deletion of genes with predicted function in the Aspergillus nidulans secretion pathway. Microb Biotechnol 2020; 13:1245-1253. [PMID: 32212325 PMCID: PMC7264891 DOI: 10.1111/1751-7915.13556] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 03/01/2020] [Indexed: 12/20/2022] Open
Abstract
Filamentous fungi are important cell factories for large-scale enzyme production. However, production levels are often low, and this limitation has stimulated research focusing on the manipulation of genes with predicted function in the protein secretory pathway. This pathway is the major route for the delivery of proteins to the cell exterior, and a positive relationship between the production of recombinant enzymes and the unfolded protein response (UPR) pathway has been observed. In this study, Aspergillus nidulans was exposed to UPR-inducing chemicals and differentially expressed genes were identified by RNA-seq. Twelve target genes were deleted in A. nidulans recombinant strains producing homologous and heterologous GH10 xylanases. The knockout of pbnA (glycosyltransferase), ydjA (Hsp40 co-chaperone), trxA (thioredoxin) and cypA (cyclophilin) improved the production of the homologous xylanase by 78, 171, 105 and 125% respectively. Interestingly, these deletions decreased the overall protein secretion, suggesting that the production of the homologous xylanase was specifically altered. However, the production of the heterologous xylanase and the secretion of total proteins were not altered by deleting the same genes. Considering the results, this approach demonstrated the possibility of rationally increase the production of a homologous enzyme, indicating that trxA, cypA, ydjA and pbnA are involved in protein production by A. nidulans.
Collapse
Affiliation(s)
- Mariane P. Zubieta
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
- Microbiology and Molecular GeneticsOklahoma State UniversityStillwaterOKUSA
| | - Jaqueline A. Gerhardt
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
| | - Marcelo V. Rubio
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
| | - César R. F. Terrasan
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
| | - Gabriela F. Persinoti
- Brazilian Biorenewables National Laboratory (LNBR)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasSPBrazil
| | - Everton P. Antoniel
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
| | - Fabiano J. Contesini
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
| | - Rolf A. Prade
- Microbiology and Molecular GeneticsOklahoma State UniversityStillwaterOKUSA
| | - André Damasio
- Department of Biochemistry and Tissue BiologyInstitute of BiologyUniversity of Campinas (UNICAMP)CampinasSPBrazil
| |
Collapse
|
11
|
Csáky Z, Garaiová M, Kodedová M, Valachovič M, Sychrová H, Hapala I. Squalene lipotoxicity in a lipid droplet‐less yeast mutant is linked to plasma membrane dysfunction. Yeast 2020; 37:45-62. [DOI: 10.1002/yea.3454] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 12/02/2019] [Accepted: 12/07/2019] [Indexed: 12/13/2022] Open
Affiliation(s)
- Zsófia Csáky
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Martina Garaiová
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Marie Kodedová
- Department of Membrane Transport, Division BIOCEV Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Martin Valachovič
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Hana Sychrová
- Department of Membrane Transport, Division BIOCEV Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Ivan Hapala
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| |
Collapse
|
12
|
Tumanovska LV, Swanson RJ, Serebrovska ZO, Portnichenko GV, Goncharov SV, Kysilov BA, Moibenko OO, Dosenko VE. Cholesterol enriched diet suppresses ATF6 and PERK and upregulates the IRE1 pathways of the unfolded protein response in spontaneously hypertensive rats: Relevance to pathophysiology of atherosclerosis in the setting of hypertension. ACTA ACUST UNITED AC 2019; 26:219-226. [PMID: 31202527 DOI: 10.1016/j.pathophys.2019.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 05/24/2019] [Accepted: 05/26/2019] [Indexed: 12/13/2022]
Abstract
Many studies have been dedicated to hypertension and hypercholesterolemia, as they are the primary conditions that influence the unfolded protein response (UPR). However, the concurrent effects of these two factors are unknown. Our research used spontaneously hypertensive rats (SHR) fed a cholesterol enriched diet (CED) as model of atherosclerosis formation to discover what effect the simultaneous actions of hypertension and hypercholesterolemia have on the UPR. The combination of hypertension and consumption of a CED (not the CED alone) caused the formation of early atherosclerotic features. Both increased expression of the CCAAT-enhancer-binding protein (CHOP) and the insulin induced gene 1 (INSIG1), which is the target gene of the sterol regulatory element-binding protein 1-c (SREBP1-c), and decreased expression of the spliced x-box binding protein1 (sXBP1) mRNA were observed in the SHR fed a CED. Cholesterol overload strongly suppressed glucose regulated protein 78 (GRP78), glucose regulated protein 94 (GRP 94), and the expression of CHOP and INSIG1 mRNA in both normotensive and hypertensive rats. Unlike other UPR factors, the sXBP1 mRNA expression was strongly downregulated in SHR fed a normal diet but upregulated in those fed a CED. The changes to UPR in the SHR fed a CED were associated with improvement of the initially impaired heart function of the rats.
Collapse
Affiliation(s)
- Lesya V Tumanovska
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - R James Swanson
- Liberty University College of Osteopathic Medicine, 306 Liberty View Lane, Lynchburg, VA 24502, USA
| | - Zoya O Serebrovska
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.
| | - Georgii V Portnichenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Sergii V Goncharov
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Bohdan A Kysilov
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Olexandr O Moibenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Victor E Dosenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| |
Collapse
|
13
|
Nemecz M, Constantin A, Dumitrescu M, Alexandru N, Filippi A, Tanko G, Georgescu A. The Distinct Effects of Palmitic and Oleic Acid on Pancreatic Beta Cell Function: The Elucidation of Associated Mechanisms and Effector Molecules. Front Pharmacol 2019; 9:1554. [PMID: 30719005 PMCID: PMC6348268 DOI: 10.3389/fphar.2018.01554] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 12/20/2018] [Indexed: 12/13/2022] Open
Abstract
In this study, we aimed to identify the mechanisms underlying the different effects of palmitic acid and oleic acid on human pancreatic beta cell function. To address this problem, the oxidative stress, endoplasmic reticulum stress, inflammation, apoptosis and their mediator molecules have been investigated in the insulin releasing beta cells exposed to palmitic and/or oleic acid. Herein, we have demonstrated that in cultured 1.1B4 beta cells oleic acid promotes neutral lipid accumulation and insulin secretion, whereas palmitic acid is poorly incorporated into triglyceride and it does not stimulate insulin secretion from human pancreatic islets at physiologically glucose concentrations. In addition, palmitic acid caused: (1) oxidative stress through a mechanism involving increases in ROS production and MMP-2 protein expression/gelatinolytic activity associated with down-regulation of SOD2 protein; (2) endoplasmic reticulum stress by up-regulation of chaperone BiP protein and unfolded protein response (UPR) transcription factors (eIF2α, ATF6, XBP1u proteins) and by PTP-1B down-regulation in both mRNA and protein levels; (3) inflammation through enhanced synthesis of proinflammatory cytokines (IL6, IL8 proteins); and (4) apoptosis by enforced proteic expression of CHOP multifunctional transcription factor. Oleic acid alone had opposite effects due to its different capacity of controlling these metabolic pathways, in particular by reduction of the ROS levels and MMP-2 activity, down-regulation of BiP, eIF2α, ATF6, XBP1u, CHOP, IL6, IL8 and by SOD2 and PTP-1B overexpression. The supplementation of saturated palmitic acid with the monounsaturated oleic acid reversed the negative effects of palmitic acid alone regulating insulin secretion from pancreatic beta cells through ROS, MMP-2, ATF6, XBP1u, IL8 reduction and SOD2, PTP-1B activation. Our findings have shown the protective action of oleic acid against palmitic acid on beta cell lipotoxicity through promotion of triglyceride accumulation and insulin secretion and regulation of some effector molecules involved in oxidative stress, endoplasmic reticulum stress, inflammation and apoptosis.
Collapse
Affiliation(s)
- Miruna Nemecz
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| | - Alina Constantin
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| | - Madalina Dumitrescu
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| | - Nicoleta Alexandru
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| | - Alexandru Filippi
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| | - Gabriela Tanko
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| | - Adriana Georgescu
- Department of Pathophysiology and Pharmacology, Institute of Cellular Biology and Pathology 'Nicolae Simionescu' of Romanian Academy, Bucharest, Romania
| |
Collapse
|
14
|
Rapoport A, Golovina EA, Gervais P, Dupont S, Beney L. Anhydrobiosis: Inside yeast cells. Biotechnol Adv 2019; 37:51-67. [DOI: 10.1016/j.biotechadv.2018.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/01/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022]
|
15
|
Pichler H, Emmerstorfer-Augustin A. Modification of membrane lipid compositions in single-celled organisms – From basics to applications. Methods 2018; 147:50-65. [DOI: 10.1016/j.ymeth.2018.06.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/18/2018] [Accepted: 06/16/2018] [Indexed: 12/12/2022] Open
|
16
|
Kadri L, Ferru-Clément R, Bacle A, Payet LA, Cantereau A, Hélye R, Becq F, Jayle C, Vandebrouck C, Ferreira T. Modulation of cellular membrane properties as a potential therapeutic strategy to counter lipointoxication in obstructive pulmonary diseases. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3069-3084. [PMID: 29960042 DOI: 10.1016/j.bbadis.2018.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/04/2018] [Accepted: 06/25/2018] [Indexed: 02/08/2023]
Abstract
Maintaining the equilibrium between saturated and unsaturated fatty acids within membrane phospholipids (PLs) is crucial to sustain the optimal membrane biophysical properties, compatible with selective organelle-based processes. Lipointoxication is a pathological condition under which saturated PLs tend to accumulate within the cell at the expense of unsaturated species, with major impacts on organelle function. Here, we show that human bronchial epithelial cells extracted from lungs of patients with Obstructive Pulmonary Diseases (OPDs), i. e. Cystic Fibrosis (CF) individuals and Smokers, display a characteristic lipointoxication signature, with excessive amounts of saturated PLs. Reconstitution of this signature in cellulo and in silico revealed that such an imbalance results in altered membrane properties and in a dramatic disorganization of the intracellular network of bronchial epithelial cells, in a process which can account for several OPD traits. Such features include Endoplasmic Reticulum-stress, constitutive IL8 secretion, bronchoconstriction and, ultimately, epithelial cell death by apoptosis. We also demonstrate that a recently-identified lipid-like molecule, which has been shown to behave as a "membrane-reshaper", counters all the lipointoxication hallmarks tested. Altogether, these insights highlight the modulation of membrane properties as a potential new strategy to heal and prevent highly detrimental symptoms associated with OPDs.
Collapse
Affiliation(s)
- Linette Kadri
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Romain Ferru-Clément
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Amélie Bacle
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Laurie-Anne Payet
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Anne Cantereau
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Reynald Hélye
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Frédéric Becq
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Christophe Jayle
- Service de Chirurgie Cardiothoracique, CHU Poitiers, Poitiers, France
| | - Clarisse Vandebrouck
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Thierry Ferreira
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France.
| |
Collapse
|
17
|
Deprez MA, Eskes E, Wilms T, Ludovico P, Winderickx J. pH homeostasis links the nutrient sensing PKA/TORC1/Sch9 ménage-à-trois to stress tolerance and longevity. MICROBIAL CELL 2018; 5:119-136. [PMID: 29487859 PMCID: PMC5826700 DOI: 10.15698/mic2018.03.618] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The plasma membrane H+-ATPase Pma1 and the vacuolar V-ATPase act in close harmony to tightly control pH homeostasis, which is essential for a vast number of physiological processes. As these main two regulators of pH are responsive to the nutritional status of the cell, it seems evident that pH homeostasis acts in conjunction with nutrient-induced signalling pathways. Indeed, both PKA and the TORC1-Sch9 axis influence the proton pumping activity of the V-ATPase and possibly also of Pma1. In addition, it recently became clear that the proton acts as a second messenger to signal glucose availability via the V-ATPase to PKA and TORC1-Sch9. Given the prominent role of nutrient signalling in longevity, it is not surprising that pH homeostasis has been linked to ageing and longevity as well. A first indication is provided by acetic acid, whose uptake by the cell induces toxicity and affects longevity. Secondly, vacuolar acidity has been linked to autophagic processes, including mitophagy. In agreement with this, a decline in vacuolar acidity was shown to induce mitochondrial dysfunction and shorten lifespan. In addition, the asymmetric inheritance of Pma1 has been associated with replicative ageing and this again links to repercussions on vacuolar pH. Taken together, accumulating evidence indicates that pH homeostasis plays a prominent role in the determination of ageing and longevity, thereby providing new perspectives and avenues to explore the underlying molecular mechanisms.
Collapse
Affiliation(s)
| | - Elja Eskes
- Functional Biology, KU Leuven, Leuven, Belgium
| | | | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | | |
Collapse
|
18
|
Welte MA, Gould AP. Lipid droplet functions beyond energy storage. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1260-1272. [PMID: 28735096 PMCID: PMC5595650 DOI: 10.1016/j.bbalip.2017.07.006] [Citation(s) in RCA: 338] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 02/07/2023]
Abstract
Lipid droplets are cytoplasmic organelles that store neutral lipids and are critically important for energy metabolism. Their function in energy storage is firmly established and increasingly well characterized. However, emerging evidence indicates that lipid droplets also play important and diverse roles in the cellular handling of lipids and proteins that may not be directly related to energy homeostasis. Lipid handling roles of droplets include the storage of hydrophobic vitamin and signaling precursors, and the management of endoplasmic reticulum and oxidative stress. Roles of lipid droplets in protein handling encompass functions in the maturation, storage, and turnover of cellular and viral polypeptides. Other potential roles of lipid droplets may be connected with their intracellular motility and, in some cases, their nuclear localization. This diversity highlights that lipid droplets are very adaptable organelles, performing different functions in different biological contexts. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
Collapse
Affiliation(s)
- Michael A Welte
- Department of Biology, University of Rochester, Rochester, NY, United States.
| | | |
Collapse
|
19
|
Ogasawara Y, Kira S, Mukai Y, Noda T, Yamamoto A. Ole1, fatty acid desaturase, is required for Atg9 delivery and isolation membrane expansion during autophagy in Saccharomyces cerevisiae. Biol Open 2017; 6:35-40. [PMID: 27881438 PMCID: PMC5278431 DOI: 10.1242/bio.022053] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/15/2016] [Indexed: 02/02/2023] Open
Abstract
Macroautophagy, a major degradation pathway of cytoplasmic components, is carried out through formation of a double-membrane structure, the autophagosome. Although the involvement of specific lipid species in the formation process remains largely obscure, we recently showed that mono-unsaturated fatty acids (MUFA) generated by stearoyl-CoA desaturase 1 (SCD1) are required for autophagosome formation in mammalian cells. To obtain further insight into the role of MUFA in autophagy, in this study we analyzed the autophagic phenotypes of the yeast mutant of OLE1, an orthologue of SCD1. Δole1 cells were defective in nitrogen starvation-induced autophagy, and the Cvt pathway, when oleic acid was not supplied. Defects in elongation of the isolation membrane led to a defect in autophagosome formation. In the absence of Ole1, the transmembrane protein Atg9 was not able to reach the pre-autophagosomal structure (PAS), the site of autophagosome formation. Thus, autophagosome formation requires Ole1 during the delivery of Atg9 to the PAS/autophagosome from its cellular reservoir.
Collapse
Affiliation(s)
- Yuta Ogasawara
- Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Shintaro Kira
- Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yukio Mukai
- Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Takeshi Noda
- Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
- Graduate school of Frontier Bioscience, Osaka University, 1-8 Yamadaoka, Suita, Japan
| | - Akitsugu Yamamoto
- Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| |
Collapse
|
20
|
Lipidomic analysis of psychrophilic yeasts cultivated at different temperatures. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1634-1642. [DOI: 10.1016/j.bbalip.2016.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/20/2016] [Accepted: 07/11/2016] [Indexed: 11/20/2022]
|
21
|
Busti S, Mapelli V, Tripodi F, Sanvito R, Magni F, Coccetti P, Rocchetti M, Nielsen J, Alberghina L, Vanoni M. Respiratory metabolism and calorie restriction relieve persistent endoplasmic reticulum stress induced by calcium shortage in yeast. Sci Rep 2016; 6:27942. [PMID: 27305947 PMCID: PMC4910072 DOI: 10.1038/srep27942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 05/27/2016] [Indexed: 11/26/2022] Open
Abstract
Calcium homeostasis is crucial to eukaryotic cell survival. By acting as an enzyme cofactor and a second messenger in several signal transduction pathways, the calcium ion controls many essential biological processes. Inside the endoplasmic reticulum (ER) calcium concentration is carefully regulated to safeguard the correct folding and processing of secretory proteins. By using the model organism Saccharomyces cerevisiae we show that calcium shortage leads to a slowdown of cell growth and metabolism. Accumulation of unfolded proteins within the calcium-depleted lumen of the endoplasmic reticulum (ER stress) triggers the unfolded protein response (UPR) and generates a state of oxidative stress that decreases cell viability. These effects are severe during growth on rapidly fermentable carbon sources and can be mitigated by decreasing the protein synthesis rate or by inducing cellular respiration. Calcium homeostasis, protein biosynthesis and the unfolded protein response are tightly intertwined and the consequences of facing calcium starvation are determined by whether cellular energy production is balanced with demands for anabolic functions. Our findings confirm that the connections linking disturbance of ER calcium equilibrium to ER stress and UPR signaling are evolutionary conserved and highlight the crucial role of metabolism in modulating the effects induced by calcium shortage.
Collapse
Affiliation(s)
- Stefano Busti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- SYSBIO, Centre of Systems Biology, Milan, Italy
| | - Valeria Mapelli
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- Department of Biology and Biological Engineering, Division of Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
| | - Farida Tripodi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- SYSBIO, Centre of Systems Biology, Milan, Italy
| | - Rossella Sanvito
- Department of Health Sciences, University of Milano-Bicocca, Milan, Italy
| | - Fulvio Magni
- Department of Health Sciences, University of Milano-Bicocca, Milan, Italy
| | - Paola Coccetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- SYSBIO, Centre of Systems Biology, Milan, Italy
| | - Marcella Rocchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Lilia Alberghina
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- SYSBIO, Centre of Systems Biology, Milan, Italy
| | - Marco Vanoni
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- SYSBIO, Centre of Systems Biology, Milan, Italy
| |
Collapse
|
22
|
Update on Mechanisms of Renal Tubule Injury Caused by Advanced Glycation End Products. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5475120. [PMID: 27034941 PMCID: PMC4789391 DOI: 10.1155/2016/5475120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/08/2016] [Indexed: 01/26/2023]
Abstract
Diabetic nephropathy (DN) caused by advanced glycation end products (AGEs) may be associated with lipid accumulation in the kidneys. This study was designed to investigate whether Nε-(carboxymethyl) lysine (CML, a member of the AGEs family) increases lipid accumulation in a human renal tubular epithelial cell line (HK-2) via increasing cholesterol synthesis and uptake and reducing cholesterol efflux through endoplasmic reticulum stress (ERS). Our results showed that CML disrupts cholesterol metabolism in HK-2 cells by activating sterol regulatory element-binding protein 2 (SREBP-2) and liver X receptor (LXR), followed by an increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) mediated cholesterol synthesis and low density lipoprotein receptor (LDLr) mediated cholesterol uptake and a reduction in ATP-binding cassette transporter A1 (ABCA1) mediated cholesterol efflux, ultimately causing lipid accumulation in HK-2 cells. All of these responses could be suppressed by an ERS inhibitor, which suggests that CML causes lipid accumulation in renal tubule cells through ERS and that the inhibition of ERS is a potential novel approach to treating CML-induced renal tubular foam cell formation.
Collapse
|
23
|
Hasnain SZ, Prins JB, McGuckin MA. Oxidative and endoplasmic reticulum stress in β-cell dysfunction in diabetes. J Mol Endocrinol 2016; 56:R33-54. [PMID: 26576641 DOI: 10.1530/jme-15-0232] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/17/2015] [Indexed: 12/12/2022]
Abstract
The inability of pancreatic β-cells to make sufficient insulin to control blood sugar is a central feature of the aetiology of most forms of diabetes. In this review we focus on the deleterious effects of oxidative stress and endoplasmic reticulum (ER) stress on β-cell insulin biosynthesis and secretion and on inflammatory signalling and apoptosis with a particular emphasis on type 2 diabetes (T2D). We argue that oxidative stress and ER stress are closely entwined phenomena fundamentally involved in β-cell dysfunction by direct effects on insulin biosynthesis and due to consequences of the ER stress-induced unfolded protein response. We summarise evidence that, although these phenomenon can be driven by intrinsic β-cell defects in rare forms of diabetes, in T2D β-cell stress is driven by a range of local environmental factors including increased drivers of insulin biosynthesis, glucolipotoxicity and inflammatory cytokines. We describe our recent findings that a range of inflammatory cytokines contribute to β-cell stress in diabetes and our discovery that interleukin 22 protects β-cells from oxidative stress regardless of the environmental triggers and can correct much of diabetes pathophysiology in animal models. Finally we summarise evidence that β-cell dysfunction is reversible in T2D and discuss therapeutic opportunities for relieving oxidative and ER stress and restoring glycaemic control.
Collapse
Affiliation(s)
- Sumaira Z Hasnain
- ImmunityInfection and Inflammation Program, Mater Research Institute, Translational Research Institute, University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, Queensland 4102, AustraliaMetabolic Diseases ProgramMater Research Institute, The University of Queensland, Translational Research Institute, 37 Kent Street, Woolloongabba, Brisbane, Queensland 4102, Australia
| | - Johannes B Prins
- ImmunityInfection and Inflammation Program, Mater Research Institute, Translational Research Institute, University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, Queensland 4102, AustraliaMetabolic Diseases ProgramMater Research Institute, The University of Queensland, Translational Research Institute, 37 Kent Street, Woolloongabba, Brisbane, Queensland 4102, Australia
| | - Michael A McGuckin
- ImmunityInfection and Inflammation Program, Mater Research Institute, Translational Research Institute, University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, Queensland 4102, AustraliaMetabolic Diseases ProgramMater Research Institute, The University of Queensland, Translational Research Institute, 37 Kent Street, Woolloongabba, Brisbane, Queensland 4102, Australia
| |
Collapse
|
24
|
Hou NS, Taubert S. Membrane lipids and the endoplasmic reticulum unfolded protein response: An interesting relationship. WORM 2014; 3:e962405. [PMID: 26430548 PMCID: PMC4588386 DOI: 10.4161/21624046.2014.962405] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/02/2014] [Indexed: 11/19/2022]
Abstract
The unfolded protein response of the endoplasmic reticulum (UPRER) is a conserved signaling circuit that ensures ER protein homeostasis (proteostasis). In the UPRER of higher eukaryotes, multiple sensors cooperatively perceive proteostatic disturbances in the ER lumen and induce downstream adaptive changes. Besides direct proteotoxic insults, altered lipid profiles can also lead to UPRER activation, evidently because abnormal lipid composition impairs protein folding. However, 2 recent studies propose an alternative mechanism of UPRER sensor activation. In one report, UPRER activation occurred in cells expressing UPRER sensors lacking the very domains that sense unfolded proteins; the other study found that Caenorhabditis elegans worms displayed UPRER activation without apparent proteostatic imbalance in the ER lumen. Collectively, these studies suggest that lipid disequilibrium-activated UPRER is not strictly accompanied by compromised ER proteostasis and hint at a lipid membrane-monitoring role of the UPRER. These discoveries raise several important questions: does the UPRER monitor and maintain homeostasis of the ER membrane and/or its lipids? In turn, does the UPRER initiate downstream regulatory events that specifically alleviate lipid or proteostatic imbalance? And what is the physiological significance of proteostasis-independent UPRER activation? In this commentary, we will discuss these issues and highlight the utility of C. elegans as an in vivo model to study lipid disequilibrium-induced UPRER and related pathways.
Collapse
Affiliation(s)
- Nicole S Hou
- Centre for Molecular Medicine and Therapeutics and Child & Family Research Institute ; Vancouver, BC, Canada
| | - Stefan Taubert
- Centre for Molecular Medicine and Therapeutics and Child & Family Research Institute ; Vancouver, BC, Canada ; Department of Medical Genetics; University of British Columbia ; Vancouver, BC, Canada
| |
Collapse
|
25
|
Zhuang A, Forbes JM. Stress in the kidney is the road to pERdition: is endoplasmic reticulum stress a pathogenic mediator of diabetic nephropathy? J Endocrinol 2014; 222:R97-111. [PMID: 24982467 DOI: 10.1530/joe-13-0517] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The endoplasmic reticulum (ER) is an organelle that primarily functions to synthesise new proteins and degrade old proteins. Owing to the continual and variable nature of protein turnover, protein synthesis is inherently an error-prone process and is therefore tightly regulated. Fortunately, if this balance between synthesis and degradation is perturbed, an intrinsic response, the unfolded protein response (UPR) is activated to restore ER homoeostasis through the action of inositol-requiring protein 1, activating transcription factor 6 and PKR-like ER kinase transmembrane sensors. However, if the UPR is oversaturated and misfolded proteins accumulate, the ER can shift into a cytotoxic response, a physiological phenomenon known as ER stress. The mechanistic pathways of the UPR have been extensively explored; however, the role of this process in such a synthetic organ as the kidney requires further clarification. This review will focus on these aspects and will discuss the role of ER stress in specific resident kidney cells and how this may be integral in the pathogenesis and progression of diabetic nephropathy (DN). Given that diabetes is a perturbed state of protein turnover in most tissues, it is important to understand if ER stress is a secondary or tertiary response to other changes within the diabetic milieu or if it is an independent accelerator of kidney disease. Modulators of ER stress could provide a valuable tool for the treatment of DN and are under active investigation in other contexts.
Collapse
Affiliation(s)
- Aowen Zhuang
- Glycation and Diabetes GroupMater Research Institute - The University of Queensland, Translational Research Institute, 37 Kent Street, Woolloongabba, South Brisbane, Queensland, AustraliaMater Clinical SchoolThe University of Queensland, South Brisbane, Queensland, Australia
| | - Josephine M Forbes
- Glycation and Diabetes GroupMater Research Institute - The University of Queensland, Translational Research Institute, 37 Kent Street, Woolloongabba, South Brisbane, Queensland, AustraliaMater Clinical SchoolThe University of Queensland, South Brisbane, Queensland, AustraliaGlycation and Diabetes GroupMater Research Institute - The University of Queensland, Translational Research Institute, 37 Kent Street, Woolloongabba, South Brisbane, Queensland, AustraliaMater Clinical SchoolThe University of Queensland, South Brisbane, Queensland, Australia
| |
Collapse
|
26
|
Liu L, Trent CM, Fang X, Son NH, Jiang H, Blaner WS, Hu Y, Yin YX, Farese RV, Homma S, Turnbull AV, Eriksson JW, Hu SL, Ginsberg HN, Huang LS, Goldberg IJ. Cardiomyocyte-specific loss of diacylglycerol acyltransferase 1 (DGAT1) reproduces the abnormalities in lipids found in severe heart failure. J Biol Chem 2014; 289:29881-91. [PMID: 25157099 DOI: 10.1074/jbc.m114.601864] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Diacylglycerol acyltransferase 1 (DGAT1) catalyzes the final step in triglyceride synthesis, the conversion of diacylglycerol (DAG) to triglyceride. Dgat1(-/-) mice exhibit a number of beneficial metabolic effects including reduced obesity and improved insulin sensitivity and no known cardiac dysfunction. In contrast, failing human hearts have severely reduced DGAT1 expression associated with accumulation of DAGs and ceramides. To test whether DGAT1 loss alone affects heart function, we created cardiomyocyte-specific DGAT1 knock-out (hDgat1(-/-)) mice. hDgat1(-/-) mouse hearts had 95% increased DAG and 85% increased ceramides compared with floxed controls. 50% of these mice died by 9 months of age. The heart failure marker brain natriuretic peptide increased 5-fold in hDgat1(-/-) hearts, and fractional shortening (FS) was reduced. This was associated with increased expression of peroxisome proliferator-activated receptor α and cluster of differentiation 36. We crossed hDgat1(-/-) mice with previously described enterocyte-specific Dgat1 knock-out mice (hiDgat1(-/-)). This corrected the early mortality, improved FS, and reduced cardiac ceramide and DAG content. Treatment of hDgat1(-/-) mice with the glucagon-like peptide 1 receptor agonist exenatide also improved FS and reduced heart DAG and ceramide content. Increased fatty acid uptake into hDgat1(-/-) hearts was normalized by exenatide. Reduced activation of protein kinase Cα (PKCα), which is increased by DAG and ceramides, paralleled the reductions in these lipids. Our mouse studies show that loss of DGAT1 reproduces the lipid abnormalities seen in severe human heart failure.
Collapse
Affiliation(s)
- Li Liu
- From the Divisions of Preventive Medicine and Nutrition and Institute of Systems Biomedicine, Peking University Health Science Center, 100083 Beijing, China
| | - Chad M Trent
- From the Divisions of Preventive Medicine and Nutrition and
| | - Xiang Fang
- From the Divisions of Preventive Medicine and Nutrition and Department of Geriatrics, Affiliated Provincial Hospital, Anhui Medical University, 230001 Hefei, China
| | - Ni-Huiping Son
- From the Divisions of Preventive Medicine and Nutrition and
| | - HongFeng Jiang
- From the Divisions of Preventive Medicine and Nutrition and
| | | | - Yunying Hu
- From the Divisions of Preventive Medicine and Nutrition and
| | - Yu-Xin Yin
- Institute of Systems Biomedicine, Peking University Health Science Center, 100083 Beijing, China
| | - Robert V Farese
- Gladstone Institute of Cardiovascular Disease and Departments of Medicine and Biochemistry and Biophysics, University of California, San Francisco, California 94158
| | - Shunichi Homma
- Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | | | - Jan W Eriksson
- Astra-Zeneca Company, 431 50 Mölndal, Sweden, Department of Medical Sciences, Uppsala University, 751 05 Uppsala, Sweden, and
| | - Shi-Lian Hu
- Department of Geriatrics, Affiliated Provincial Hospital, Anhui Medical University, 230001 Hefei, China
| | | | - Li-Shin Huang
- From the Divisions of Preventive Medicine and Nutrition and
| | - Ira J Goldberg
- From the Divisions of Preventive Medicine and Nutrition and Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, Division of Endocrinology, Diabetes, and Metabolism, New York University Langone School of Medicine, New York, New York 10016
| |
Collapse
|
27
|
Sukhanova EI, Rogov AG, Severin FF, Zvyagilskaya RA. Phenoptosis in yeasts. BIOCHEMISTRY (MOSCOW) 2014; 77:761-75. [PMID: 22817540 DOI: 10.1134/s0006297912070097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The current view on phenoptosis and apoptosis as genetic programs aimed at eliminating potentially dangerous organisms and cells, respectively, is given. Special emphasis is placed on apoptosis (phenoptosis) in yeasts: intracellular defects and a plethora of external stimuli inducing apoptosis in yeasts; distinctive morphological and biochemical hallmarks accompanying apoptosis in yeasts; pro- and antiapoptotic factors involved in yeast apoptosis signaling; consecutive stages of apoptosis from external stimulus to the cell death; a prominent role of mitochondria and other organelles in yeast apoptosis; possible pathways for release of apoptotic factors from the intermembrane mitochondrial space into the cytosol are described. Using some concrete examples, the obvious physiological importance and expediency of altruistic death of yeast cells is shown. Poorly known aspects of yeast apoptosis and prospects for yeast apoptosis study are defined.
Collapse
Affiliation(s)
- E I Sukhanova
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 119071, Russia
| | | | | | | |
Collapse
|
28
|
Hou J, Tang H, Liu Z, Österlund T, Nielsen J, Petranovic D. Management of the endoplasmic reticulum stress by activation of the heat shock response in yeast. FEMS Yeast Res 2013; 14:481-94. [PMID: 24237754 DOI: 10.1111/1567-1364.12125] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 11/04/2013] [Accepted: 11/06/2013] [Indexed: 11/30/2022] Open
Abstract
In yeast Saccharomyces cerevisiae, accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates the unfolded protein response (UPR), which is mediated by Hac1p. The heat shock response (HSR) mediated by Hsf1p, mainly regulates cytosolic processes and protects the cell from stresses. Here, we find that a constitutive activation of the HSR could increase ER stress resistance in both wild-type and UPR-deficient cells. Activation of HSR decreased UPR activation in the WT (as shown by the decreased HAC1 mRNA splicing). We analyzed the genome-wide transcriptional response in order to propose regulatory mechanisms that govern the interplay between UPR and HSR and followed up for the hypotheses by experiments in vivo and in vitro. Interestingly, we found that the regulation of ER stress response via HSR is (1) only partially dependent on over-expression of Kar2p (ER resident chaperone induced by ER stress); (2) does not involve the increase in protein turnover via the proteasome activity; (3) is related to the oxidative stress response. From the transcription data, we also propose that HSR enhances ER stress resistance mainly through facilitation of protein folding and secretion. We also find that HSR coordinates multiple stress-response pathways, including the repression of the overall transcription and translation.
Collapse
Affiliation(s)
- Jin Hou
- Novo Nordisk Foundation Center for Biosustainability, Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden; State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, China
| | | | | | | | | | | |
Collapse
|
29
|
Sommerweiss D, Gorski T, Richter S, Garten A, Kiess W. Oleate rescues INS-1E β-cells from palmitate-induced apoptosis by preventing activation of the unfolded protein response. Biochem Biophys Res Commun 2013; 441:770-6. [PMID: 24189472 DOI: 10.1016/j.bbrc.2013.10.130] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 10/24/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Saturated free fatty acids (FFAs), such as palmitate, cause β-cell apoptosis whereas unsaturated FFAs, e.g. oleate, are not harmful. The toxicity of palmitate could be mediated through endoplasmic reticulum (ER) stress which triggers the activation of a signal responding cascade also called unfolded protein response (UPR). We investigated whether or not palmitate induced β-cell apoptosis through UPR activation and whether or not oleate as a monounsaturated fatty acid could counteract these effects. METHODS INS-1E β-cells were incubated with palmitate [0.5mM], oleate [1mM] or the combination [0.5/1mM] for 1, 6 and 24h. Viability and induction of apoptosis were measured by WST-1 assay and FITC-Annexin/PI-staining, respectively. Western blot analyses were performed for UPR specific proteins and mRNA expression of target molecules was determined by qPCR. RESULTS Palmitate significantly decreased viability (29±8.8%) of INS-1E β-cells compared to controls after 24h. Stimulation with oleate showed no effect on viability but the combination of oleate and palmitate improved viability compared to palmitate treated cells (55±9.3%) or controls (26±5.3%). The number of apoptotic cells was increased 2-fold after 24h incubation with palmitate compared to controls. Again, oleate showed no effect but in combination ameliorated the effect of palmitate to control level. Phosphorylation of eIF2α was increased after 6 and 24h incubation with palmitate. In contrast, oleate had no effect and in combination prevented phosphorylation of eIF2α. Increased Xbp1 splicing was visible already 6h after palmitate treatment and remained elevated at 24h. The combination with oleate abolished Xbp1 splicing. Interestingly, mRNA expression of the chaperones Bip, Pdi, Calnexin and Grp94 was not altered by FFA treatment. Only the proapoptotic transcription factor Chop was significantly enhanced by palmitate incubation. In accordance with sustained cell survival the combination as well as oleate alone, did not result in increased Chop levels compared to controls. In summary, we showed that oleate protects INS-1E β-cells from palmitate-induced apoptosis by the suppression of ER stress which was independent of chaperone activation.
Collapse
Affiliation(s)
- Dietlind Sommerweiss
- Center for Pediatric Research Leipzig (CPL), Hospital for Children and Adolescents, University of Leipzig, Germany
| | | | | | | | | |
Collapse
|
30
|
Payet LA, Pineau L, Snyder ECR, Colas J, Moussa A, Vannier B, Bigay J, Clarhaut J, Becq F, Berjeaud JM, Vandebrouck C, Ferreira T. Saturated Fatty Acids Alter the Late Secretory Pathway by Modulating Membrane Properties. Traffic 2013; 14:1228-41. [DOI: 10.1111/tra.12117] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 01/26/2023]
Affiliation(s)
- Laurie-Anne Payet
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| | | | - Ellen C. R. Snyder
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| | - Jenny Colas
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| | - Ahmed Moussa
- Ecole Nationale des Sciences Appliquées de Tanger; BP 1818 90000 Tanger Morocco
| | - Brigitte Vannier
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| | - Joelle Bigay
- Institut de Pharmacologie Moléculaire et Cellulaire; UMR CNRS 7275, Université de Nice-Sophia Antipolis; 660 Route des Lucioles, Sophia Antipolis 06560 Valbonne France
| | - Jonathan Clarhaut
- INSERM CIC 0802; CHU de Poitiers; 2 rue de la Milétrie 86021 Poitiers France
| | - Frédéric Becq
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| | - Jean-Marc Berjeaud
- Université de Poitiers; Ecologie et Biologie des Interactions; UMR CNRS 7267, 40 avenue du Recteur Pineau 86022 Poitiers Cedex France
| | - Clarisse Vandebrouck
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| | - Thierry Ferreira
- Université de Poitiers; Institut de Physiologie et de Biologie Cellulaires; FRE CNRS 3511, Pôle Biologie-Santé, 1, Rue Georges BONNET, BP 633 86022 Poitiers Cedex France
| |
Collapse
|
31
|
Appenzeller-Herzog C, Hall MN. Bidirectional crosstalk between endoplasmic reticulum stress and mTOR signaling. Trends Cell Biol 2012; 22:274-82. [PMID: 22444729 DOI: 10.1016/j.tcb.2012.02.006] [Citation(s) in RCA: 241] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 02/20/2012] [Accepted: 02/24/2012] [Indexed: 12/18/2022]
Abstract
Many cellular processes including apoptosis, autophagy, translation, energy metabolism, and inflammation are controlled by the mammalian target of rapamycin (mTOR) kinase and the endoplasmic reticulum (ER) stress pathway, also known as the unfolded protein response (UPR). Although both of these signaling nodes have attracted wide attention in fundamental cell biology and drug discovery, crosstalk between the two pathways has emerged only very recently. mTOR complex 1 (mTORC1) operates both upstream and downstream of ER stress signals, which can either enhance or antagonize the anabolic output of mTORC1. Upon prolonged ER stress, mTORC1 contributes to apoptotic signaling by suppressing the survival kinase Akt through feedback inhibition. Likewise, chronic ER stress obstructs activation of Akt by mTOR complex 2. This review surveys our knowledge of mTOR-ER stress intersections and highlights potential therapeutic implications.
Collapse
Affiliation(s)
- Christian Appenzeller-Herzog
- Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
| | | |
Collapse
|
32
|
Costa IM, Nasser THT, Demasi M, Nascimento RMP, Netto LES, Miyamoto S, Prado FM, Monteiro G. The promoter of filamentation (POF1) protein from Saccharomyces cerevisiae is an ATPase involved in the protein quality control process. BMC Microbiol 2011; 11:268. [PMID: 22204397 PMCID: PMC3282682 DOI: 10.1186/1471-2180-11-268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 12/28/2011] [Indexed: 12/05/2022] Open
Abstract
Background The gene YCL047C, which has been renamed promoter of filamentation gene (POF1), has recently been described as a cell component involved in yeast filamentous growth. The objective of this work is to understand the molecular and biological function of this gene. Results Here, we report that the protein encoded by the POF1 gene, Pof1p, is an ATPase that may be part of the Saccharomyces cerevisiae protein quality control pathway. According to the results, Δpof1 cells showed increased sensitivity to hydrogen peroxide, tert-butyl hydroperoxide, heat shock and protein unfolding agents, such as dithiothreitol and tunicamycin. Besides, the overexpression of POF1 suppressed the sensitivity of Δpct1, a strain that lacks a gene that encodes a phosphocholine cytidylyltransferase, to heat shock. In vitro analysis showed, however, that the purified Pof1p enzyme had no cytidylyltransferase activity but does have ATPase activity, with catalytic efficiency comparable to other ATPases involved in endoplasmic reticulum-associated degradation of proteins (ERAD). Supporting these findings, co-immunoprecipitation experiments showed a physical interaction between Pof1p and Ubc7p (an ubiquitin conjugating enzyme) in vivo. Conclusions Taken together, the results strongly suggest that the biological function of Pof1p is related to the regulation of protein degradation.
Collapse
Affiliation(s)
- Iris M Costa
- Departamento de Tecnologia Bioquímico-Farmacêutica, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo - USP, São Paulo-SP, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Is fat so bad? Modulation of endoplasmic reticulum stress by lipid droplet formation. Biol Cell 2011; 103:271-85. [PMID: 21729000 DOI: 10.1042/bc20100144] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
LDs (lipid droplets) have long been considered as inert particles used by the cells to store fatty acids and sterols as esterified non-toxic lipid species (i.e. triacylglycerols and steryl esters). However, accumulating evidence suggests that LDs behave as a dynamic compartment, which is involved in the regulation of several aspects of the homoeostasis of their originating organelle, namely the ER (endoplasmic reticulum). The ER is particularly sensitive to physiological/pathological stimuli, which can ultimately induce ER stress. In the present review, after considering the basic mechanisms of LD formation and the signal cascades leading to ER stress, we focus on the connections between these two pathways. Taking into consideration recent data from the literature, we will try to draw possible mechanisms for the role of LDs in the regulation of ER homoeostasis and in ER-stress-related diseases.
Collapse
|
34
|
Perman JC, Boström P, Lindbom M, Lidberg U, StÅhlman M, Hägg D, Lindskog H, Scharin Täng M, Omerovic E, Mattsson Hultén L, Jeppsson A, Petursson P, Herlitz J, Olivecrona G, Strickland DK, Ekroos K, Olofsson SO, Borén J. The VLDL receptor promotes lipotoxicity and increases mortality in mice following an acute myocardial infarction. J Clin Invest 2011; 121:2625-40. [PMID: 21670500 DOI: 10.1172/jci43068] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 04/20/2011] [Indexed: 12/18/2022] Open
Abstract
Impaired cardiac function is associated with myocardial triglyceride accumulation, but it is not clear how the lipids accumulate or whether this accumulation is detrimental. Here we show that hypoxia/ischemia-induced accumulation of lipids in HL-1 cardiomyocytes and mouse hearts is dependent on expression of the VLDL receptor (VLDLR). Hypoxia-induced VLDLR expression in HL-1 cells was dependent on HIF-1α through its interaction with a hypoxia-responsive element in the Vldlr promoter, and VLDLR promoted the endocytosis of lipoproteins. Furthermore, VLDLR expression was higher in ischemic compared with nonischemic left ventricles from human hearts and was correlated with the total lipid droplet area in the cardiomyocytes. Importantly, Vldlr-/- mice showed improved survival and decreased infarct area following an induced myocardial infarction. ER stress, which leads to apoptosis, is known to be involved in ischemic heart disease. We found that ischemia-induced ER stress and apoptosis in mouse hearts were reduced in Vldlr-/- mice and in mice treated with antibodies specific for VLDLR. These findings suggest that VLDLR-induced lipid accumulation in the ischemic heart worsens survival by increasing ER stress and apoptosis.
Collapse
Affiliation(s)
- Jeanna C Perman
- Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, Sahlgrenska University Hospital, Göteborg, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Deguil J, Pineau L, Rowland Snyder EC, Dupont S, Beney L, Gil A, Frapper G, Ferreira T. Modulation of lipid-induced ER stress by fatty acid shape. Traffic 2011; 12:349-62. [PMID: 21143717 DOI: 10.1111/j.1600-0854.2010.01150.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Exposure of pancreatic β cells to long-chain saturated fatty acids (SFA) induces a so-called endoplasmic reticulum (ER) stress that can ultimately lead to cell death. This process is believed to participate in insulin deficiency associated with type 2 diabetes, via a decrease in β-cell mass. By contrast, some unsaturated fatty acid species appear less toxic to the cells and can even alleviate SFA-induced ER stress. In the present study, we took advantage of a simple yeast-based model, which brings together most of the trademarks of lipotoxicity in human cells, to screen fatty acids of various structures for their capacity to counter ER stress. Here we demonstrate that the tendency of a free fatty acid (FFA) to reduce SFA toxicity depends on a complex conjunction of parameters, including chain length, level of unsaturation, position of the double bonds and nature of the isomers (cis or trans). Interestingly, potent FFA act as building blocks for phospholipid synthesis and help to restore an optimal membrane organization, compatible with ER function and normal protein trafficking.
Collapse
Affiliation(s)
- Julie Deguil
- Institut de Physiologie et Biologie Cellulaires, Université de POITIERS, CNRS UMR 6187, 40 Avenue du Recteur Pineau, 86022 Poitiers, France
| | | | | | | | | | | | | | | |
Collapse
|