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Rajakumar T, Hossain MA, Stopka SA, Micoogullari Y, Ang J, Agar NYR, Hanna J. Dysregulation of ceramide metabolism causes phytoceramide-dependent induction of the unfolded protein response. Mol Biol Cell 2024; 35:ar117. [PMID: 39024283 DOI: 10.1091/mbc.e24-03-0121] [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: 07/20/2024] Open
Abstract
The unfolded protein response (UPR) detects and mitigates the harmful effects of dysregulated endoplasmic reticulum (ER) function. The UPR has been best characterized as a protein quality control response, and the sole UPR sensor in yeast, Ire1, is known to detect misfolded ER proteins. However, recent work suggests the UPR can also sense diverse defects within the ER membrane, including increased fatty acid saturation and altered phospholipid abundance. These and other lipid-related stimuli have been referred to as lipid bilayer stress and may be sensed independently through Ire1's transmembrane domain. Here, we show that the loss of Isc1, a phospholipase that catabolizes complex ceramides, causes UPR induction, even in the absence of exogenous stress. A series of chemical and genetic approaches identified a requirement for very long-chain fatty acid (VLCFA)-containing phytoceramides for UPR induction. In parallel, comprehensive lipidomics analyses identified large increases in the abundance of specific VLCFA-containing phytoceramides in the isc1Δ mutant. We failed to identify evidence of an accompanying defect in protein quality control or ER-associated protein degradation. These results extend our understanding of lipid bilayer stress in the UPR and provide a foundation for mechanistic investigation of this fascinating intersection between ceramide metabolism, membrane homeostasis, and the UPR.
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Affiliation(s)
- Tamayanthi Rajakumar
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Md Amin Hossain
- Department of Neurosurgery, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Sylwia A Stopka
- Department of Neurosurgery, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Yagmur Micoogullari
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Jessie Ang
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - Nathalie Y R Agar
- Department of Neurosurgery, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115
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2
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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.
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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
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3
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Miller JM, Tragesser-Tiña ME, Turk SM, Rubenstein EM. Loss of transcriptional regulator of phospholipid biosynthesis alters post-translational modification of Sec61 translocon beta subunit Sbh1 in Saccharomyces cerevisiae. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001260. [PMID: 39071171 PMCID: PMC11282434 DOI: 10.17912/micropub.biology.001260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2024] [Revised: 07/09/2024] [Accepted: 07/11/2024] [Indexed: 07/30/2024]
Abstract
We recently discovered that disrupting phospholipid biosynthesis by eliminating the Ino2/4 transcriptional regulator impairs endoplasmic reticulum (ER)-associated degradation (ERAD) in Saccharomyces cerevisiae , but the mechanism is unclear. Phosphatidylcholine deficiency has been reported to accelerate degradation of Sec61 translocon beta subunit Sbh1 and ERAD cofactor Cue1. Here, we found that, unlike targeted phosphatidylcholine depletion, INO4 deletion does not destabilize Sbh1 or Cue1. However, we observed altered electrophoretic mobility of Sbh1 in ino4 Δ yeast, consistent with phospholipid-responsive post-translational modification. A better understanding of the molecular consequences of disrupted lipid homeostasis could lead to enhanced treatments for conditions associated with perturbed lipid biosynthesis.
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Affiliation(s)
| | - Mary E. Tragesser-Tiña
- Department of Biology, Ball State University
- Diabetes, Obesity, and Complications Therapeutic Area, Eli Lilly and Company
| | - Samantha M. Turk
- Department of Biology, Ball State University
- Graduate School of Biomedical Sciences and Department of Developmental Neurobiology, St. Jude Graduate School of Biomedical Science
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Dukic B, Ruppert Z, Tóth ME, Hunya Á, Czibula Á, Bíró P, Tiszlavicz Á, Péter M, Balogh G, Erdélyi M, Timinszky G, Vígh L, Gombos I, Török Z. Mild Hyperthermia-Induced Thermogenesis in the Endoplasmic Reticulum Defines Stress Response Mechanisms. Cells 2024; 13:1141. [PMID: 38994992 PMCID: PMC11240596 DOI: 10.3390/cells13131141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/13/2024] Open
Abstract
Previous studies reported that a mild, non-protein-denaturing, fever-like temperature increase induced the unfolded protein response (UPR) in mammalian cells. Our dSTORM super-resolution microscopy experiments revealed that the master regulator of the UPR, the IRE1 (inositol-requiring enzyme 1) protein, is clustered as a result of UPR activation in a human osteosarcoma cell line (U2OS) upon mild heat stress. Using ER thermo yellow, a temperature-sensitive fluorescent probe targeted to the endoplasmic reticulum (ER), we detected significant intracellular thermogenesis in mouse embryonic fibroblast (MEF) cells. Temperatures reached at least 8 °C higher than the external environment (40 °C), resulting in exceptionally high ER temperatures similar to those previously described for mitochondria. Mild heat-induced thermogenesis in the ER of MEF cells was likely due to the uncoupling of the Ca2+/ATPase (SERCA) pump. The high ER temperatures initiated a pronounced cytosolic heat-shock response in MEF cells, which was significantly lower in U2OS cells in which both the ER thermogenesis and SERCA pump uncoupling were absent. Our results suggest that depending on intrinsic cellular properties, mild hyperthermia-induced intracellular thermogenesis defines the cellular response mechanism and determines the outcome of hyperthermic stress.
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Affiliation(s)
- Barbara Dukic
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
- Doctoral School of Environmental Sciences, Faculty of Science and Informatics, University of Szeged, 6720 Szeged, Hungary
| | - Zsófia Ruppert
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, 6720 Szeged, Hungary
| | - Melinda E Tóth
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Ákos Hunya
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Ágnes Czibula
- Laboratory of DNA Damage and Nuclear Dynamics, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
- Department of Immunology, University of Szeged, 6720 Szeged, Hungary
| | - Péter Bíró
- Department of Optics and Quantum Electronics, University of Szeged, 6720 Szeged, Hungary
| | - Ádám Tiszlavicz
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Mária Péter
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Gábor Balogh
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Miklós Erdélyi
- Department of Optics and Quantum Electronics, University of Szeged, 6720 Szeged, Hungary
| | - Gyula Timinszky
- Laboratory of DNA Damage and Nuclear Dynamics, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - László Vígh
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Imre Gombos
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Zsolt Török
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
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Kettel P, Karagöz GE. Endoplasmic reticulum: Monitoring and maintaining protein and membrane homeostasis in the endoplasmic reticulum by the unfolded protein response. Int J Biochem Cell Biol 2024; 172:106598. [PMID: 38768891 DOI: 10.1016/j.biocel.2024.106598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 05/22/2024]
Abstract
The endoplasmic reticulum (ER) regulates essential cellular processes, including protein folding, lipid synthesis, and calcium homeostasis. The ER homeostasis is maintained by a conserved set of signaling cascades called the Unfolded Protein Response (UPR). How the UPR senses perturbations in ER homeostasis has been the subject of active research for decades. In metazoans, the UPR consists of three ER-membrane embedded sensors: IRE1, PERK and ATF6. These sensors detect the accumulation of misfolded proteins in the ER lumen and adjust protein folding capacity according to cellular needs. Early work revealed that the ER-resident chaperone BiP binds to all three UPR sensors in higher eukaryotes and BiP binding was suggested to regulate their activity. More recent data have shown that in higher eukaryotes the interaction of the UPR sensors with a complex network of chaperones and misfolded proteins modulates their activation and deactivation dynamics. Furthermore, emerging evidence suggests that the UPR monitors ER membrane integrity beyond protein folding defects. However, the mechanistic and structural basis of UPR activation by proteotoxic and lipid bilayer stress in higher eukaryotes remains only partially understood. Here, we review the current understanding of novel protein interaction networks and the contribution of the lipid membrane environment to UPR activation.
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Affiliation(s)
- Paulina Kettel
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - G Elif Karagöz
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria; Medical University of Vienna, Vienna, Austria.
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6
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Niemelä LRK, Koskela EV, Frey AD. Modification of the endoplasmic reticulum morphology enables improved recombinant antibody expression in Saccharomyces cerevisiae. J Biotechnol 2024; 387:1-11. [PMID: 38555020 DOI: 10.1016/j.jbiotec.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 03/23/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
The yeast Saccharomyces cerevisiae is a versatile cell factory used for manufacturing of a wide range of products, among them recombinant proteins. Protein folding is one of the rate-limiting processes and this shortcoming is often overcome by the expression of folding catalysts and chaperones in the endoplasmic reticulum (ER). In this work, we aimed to establish the impact of ER structure on cellular productivity. The reticulon proteins Rtn1p and Rtn2p, and Yop1p are membrane curvature inducing proteins that define the morphology of the ER and depletion of these proteins creates yeast cells with a higher ER sheet-to-tubule ratio. We created yeast strains with different combinations of deletions of Rtn1p, Rtn2p, and Yop1p coding genes in cells with a normal or expanded ER lumen. We identified strains that reached up to 2.2-fold higher antibody titres compared to the control strain. The expanded ER membrane reached by deletion of the lipid biosynthesis repressor OPI1 was essential for the increased productivity. The improved specific productivity was accompanied by an up to 2-fold enlarged ER surface area and a 1.5-fold increased cross-sectional cell area. Furthermore, the strains with enlarged ER displayed an attenuated unfolded protein response. These results underline the impact that ER structures have on productivity and support the notion that reprogramming subcellular structures belongs into the toolbox of synthetic biology.
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Affiliation(s)
- Laura R K Niemelä
- Aalto University, Department of Bioproducts and Biosystems, Espoo, Finland
| | - Essi V Koskela
- Aalto University, Department of Bioproducts and Biosystems, Espoo, Finland
| | - Alexander D Frey
- Aalto University, Department of Bioproducts and Biosystems, Espoo, Finland.
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Hong S, Lee HG, Huh WK. ARV1 deficiency induces lipid bilayer stress and enhances rDNA stability by activating the unfolded protein response in Saccharomyces cerevisiae. J Biol Chem 2024; 300:107273. [PMID: 38588806 PMCID: PMC11089378 DOI: 10.1016/j.jbc.2024.107273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 03/18/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024] Open
Abstract
The stability of ribosomal DNA (rDNA) is maintained through transcriptional silencing by the NAD+-dependent histone deacetylase Sir2 in Saccharomyces cerevisiae. Alongside proteostasis, rDNA stability is a crucial factor regulating the replicative lifespan of S. cerevisiae. The unfolded protein response (UPR) is induced by misfolding of proteins or an imbalance of membrane lipid composition and is responsible for degrading misfolded proteins and restoring endoplasmic reticulum (ER) membrane homeostasis. Recent investigations have suggested that the UPR can extend the replicative lifespan of yeast by enhancing protein quality control mechanisms, but the relationship between the UPR and rDNA stability remains unknown. In this study, we found that the deletion of ARV1, which encodes an ER protein of unknown molecular function, activates the UPR by inducing lipid bilayer stress. In arv1Δ cells, the UPR and the cell wall integrity pathway are activated independently of each other, and the high osmolarity glycerol (HOG) pathway is activated in a manner dependent on Ire1, which mediates the UPR. Activated Hog1 translocates the stress response transcription factor Msn2 to the nucleus, where it promotes the expression of nicotinamidase Pnc1, a well-known Sir2 activator. Following Sir2 activation, rDNA silencing and rDNA stability are promoted. Furthermore, the loss of other ER proteins, such as Pmt1 or Bst1, and ER stress induced by tunicamycin or inositol depletion also enhance rDNA stability in a Hog1-dependent manner. Collectively, these findings suggest that the induction of the UPR enhances rDNA stability in S. cerevisiae by promoting the Msn2-Pnc1-Sir2 pathway in a Hog1-dependent manner.
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Affiliation(s)
- Sujin Hong
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyeon-Geun Lee
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea; Institute of Microbiology, Seoul National University, Seoul, Republic of Korea.
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8
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Liu X, Ren B, Fang Y, Ren J, Wang X, Gu M, Zhou F, Xiao R, Luo X, You L, Zhao Y. Comprehensive analysis of bulk and single-cell transcriptomic data reveals a novel signature associated with endoplasmic reticulum stress, lipid metabolism, and liver metastasis in pancreatic cancer. J Transl Med 2024; 22:393. [PMID: 38685045 PMCID: PMC11057100 DOI: 10.1186/s12967-024-05158-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with high probability of recurrence and distant metastasis. Liver metastasis is the predominant metastatic mode developed in most pancreatic cancer cases, which seriously affects the overall survival rate of patients. Abnormally activated endoplasmic reticulum stress and lipid metabolism reprogramming are closely related to tumor growth and metastasis. This study aims to construct a prognostic model based on endoplasmic reticulum stress and lipid metabolism for pancreatic cancer, and further explore its correlation with tumor immunity and the possibility of immunotherapy. METHODS Transcriptomic and clinical data are acquired from TCGA, ICGC, and GEO databases. Potential prognostic genes were screened by consistent clustering and WGCNA methods, and the whole cohort was randomly divided into training and testing groups. The prognostic model was constructed by machine learning method in the training cohort and verified in the test, TCGA and ICGC cohorts. The clinical application of this model and its relationship with tumor immunity were analyzed, and the relationship between endoplasmic reticulum stress and intercellular communication was further explored. RESULTS A total of 92 characteristic genes related to endoplasmic reticulum stress, lipid metabolism and liver metastasis were identified in pancreatic cancer. We established and validated a prognostic model for pancreatic cancer with 7 signatures, including ADH1C, APOE, RAP1GAP, NPC1L1, P4HB, SOD2, and TNFSF10. This model is considered to be an independent prognosticator and is a more accurate predictor of overall survival than age, gender, and stage. TIDE score was increased in high-risk group, while the infiltration levels of CD8+ T cells and M1 macrophages were decreased. The number and intensity of intercellular communication were increased in the high ER stress group. CONCLUSIONS We constructed and validated a novel prognostic model for pancreatic cancer, which can also be used as an instrumental variable to predict the prognosis and immune microenvironment. In addition, this study revealed the effect of ER stress on cell-cell communication in the tumor microenvironment.
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Affiliation(s)
- Xiaohong Liu
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Bo Ren
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Yuan Fang
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Jie Ren
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Xing Wang
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Minzhi Gu
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Feihan Zhou
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Ruiling Xiao
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Xiyuan Luo
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China
| | - Lei You
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China.
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China.
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China.
| | - Yupei Zhao
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China.
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, 100023, People's Republic of China.
- National Science and Technology Key Infrastructure On Translational Medicine in Peking Union Medical College Hospital, Beijing, 100023, People's Republic of China.
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Zhao J, He C, Fan X, Wang L, Zhao L, Liu H, Shen W, Jiang S, Pei K, Gao J, Qi Y, Liu Y, Zhao J, Zhang R, Lu C, Tong J, Huai J. Tripeptidyl peptidase II coordinates the homeostasis of calcium and lipids in the central nervous system and its depletion causes presenile dementia in female mice through calcium/lipid dyshomeostasis-induced autophagic degradation of CYP19A1. Theranostics 2024; 14:1390-1429. [PMID: 38389851 PMCID: PMC10879859 DOI: 10.7150/thno.92571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/19/2024] [Indexed: 02/24/2024] Open
Abstract
Rationale: Tripeptidyl peptidase II (TPP2) has been proven to be related to human immune and neurological diseases. It is generally considered as a cytosolic protein which forms the largest known protease complex in eukaryotic cells to operate mostly downstream of proteasomes for degradation of longer peptides. However, this canonical function of TPP2 cannot explain its role in a wide variety of biological and pathogenic processes. The mechanistic interrelationships and hierarchical order of these processes have yet to be clarified. Methods: Animals, cells, plasmids, and viruses established and/or used in this study include: TPP2 knockout mouse line, TPP2 conditional knockout mouse lines (different neural cell type oriented), TRE-TPP2 knockin mouse line on the C57BL/6 background; 293T cells with depletion of TPP2, ATF6, IRE1, PERK, SYVN1, UCHL1, ATG5, CEPT1, or CCTα, respectively; 293T cells stably expressing TPP2, TPP2 S449A, TPP2 S449T, or CCTα-KDEL proteins on the TPP2-depleted background; Plasmids for eukaryotic transient expression of rat CYP19A1-Flag, CYP19A1 S118A-Flag, CYP19A1 S118D-Flag, Sac I ML GFP Strand 11 Long, OMMGFP 1-10, G-CEPIA1er, GCAMP2, CEPIA3mt, ACC-GFP, or SERCA1-GFP; AAV2 carrying the expression cassette of mouse CYP19A1-3 X Flag-T2A-ZsGreen. Techniques used in this study include: Flow cytometry, Immunofluorescence (IF) staining, Immunohistochemical (IHC) staining, Luxol fast blue (LFB) staining, β-galactosidase staining, Lipid droplet (LD) staining, Calcium (Ca2+) staining, Stimulated emission depletion (STED) imaging, Transmission electron microscopic imaging, Two-photon imaging, Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end Labeling (TUNEL) assay, Bromodeoxyuridine (BrdU) assay, Enzymatic activity assay, Proximity ligation assay (PLA), In vivo electrophysiological recording, Long-term potentiation (LTP) recording, Split-GFP-based mitochondria-associated membrane (MAM) detection, Immunoprecipitation (IP), Cellular fractionation, In situ hybridization, Semi-quantitative RT-PCR, Immunoblot, Mass spectrometry-based lipidomics, metabolomics, proteomics, Primary hippocampal neuron culture and Morris water maze (MWM) test. Results: We found that TPP2, independent of its enzymatic activity, plays a crucial role in maintaining the homeostasis of intracellular Ca2+ and phosphatidylcholine (PC) in the central nervous system (CNS) of mice. In consistence with the critical importance of Ca2+ and PC in the CNS, TPP2 gene ablation causes presenile dementia in female mice, which is closely associated with Ca2+/PC dysregulation-induced endoplasmic reticulum (ER) stress, abnormal autophagic degradation of CYP19A1 (aromatase), and estrogen depletion. This work therefore uncovers a new role of TPP2 in lipogenesis and neurosteroidogenesis which is tightly related to cognitive function of adult female mice. Conclusion: Our study reveals a crucial role of TPP2 in controlling homeostasis of Ca2+ and lipids in CNS, and its deficiency causes sexual dimorphism in dementia. Thus, this study is not only of great significance for elucidating the pathogenesis of dementia and its futural treatment, but also for interpreting the role of TPP2 in other systems and their related disorders.
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Affiliation(s)
- Jin Zhao
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Chengtong He
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Xueyu Fan
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Lin Wang
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Liao Zhao
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Hui Liu
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Wujun Shen
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Sanwei Jiang
- Henan International Key Laboratory for Noninvasive Neuromodulation, Department of Physiology & Pathology, Xinxiang Medical University, Xinxiang, PR China
| | - Kaixuan Pei
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Jingjing Gao
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Yawei Qi
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Yang Liu
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Junqiang Zhao
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
| | - Ruiling Zhang
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
| | - Chengbiao Lu
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
- Henan International Key Laboratory for Noninvasive Neuromodulation, Department of Physiology & Pathology, Xinxiang Medical University, Xinxiang, PR China
- Senior author for electrophysiological experiments and related analysis
| | - Jia Tong
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
| | - Jisen Huai
- The Second Affiliated Hospital of Xinxiang Medical University (Henan Mental Hospital), Xinxiang, 453000, PR China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003, PR China
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10
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Suarato G, Pressi S, Menna E, Ruben M, Petrini EM, Barberis A, Miele D, Sandri G, Salerno M, Schirato A, Alabastri A, Athanassiou A, Proietti Zaccaria R, Papadopoulou EL. Modified Carbon Nanotubes Favor Fibroblast Growth by Tuning the Cell Membrane Potential. ACS APPLIED MATERIALS & INTERFACES 2024; 16:3093-3105. [PMID: 38206310 PMCID: PMC10811621 DOI: 10.1021/acsami.3c14527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/20/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024]
Abstract
As is known, carbon nanotubes favor cell growth in vitro, although the underlying mechanisms are not yet fully elucidated. In this study, we explore the hypothesis that electrostatic fields generated at the interface between nonexcitable cells and appropriate scaffold might favor cell growth by tuning their membrane potential. We focused on primary human fibroblasts grown on electrospun polymer fibers (poly(lactic acid)─PLA) with embedded multiwall carbon nanotubes (MWCNTs). The MWCNTs were functionalized with either the p-methoxyphenyl (PhOME) or the p-acetylphenyl (PhCOMe) moiety, both of which allowed uniform dispersion in a solvent, good mixing with PLA and the consequent smooth and homogeneous electrospinning process. The inclusion of the electrically conductive MWCNTs in the insulating PLA matrix resulted in differences in the surface potential of the fibers. Both PLA and PLA/MWCNT fiber samples were found to be biocompatible. The main features of fibroblasts cultured on different substrates were characterized by scanning electron microscopy, immunocytochemistry, Rt-qPCR, and electrophysiology revealing that fibroblasts grown on PLA/MWCNT reached a healthier state as compared to pure PLA. In particular, we observed physiological spreading, attachment, and Vmem of fibroblasts on PLA/MWCNT. Interestingly, the electrical functionalization of the scaffold resulted in a more suitable extracellular environment for the correct biofunctionality of these nonexcitable cells. Finally, numerical simulations were also performed in order to understand the mechanism behind the different cell behavior when grown either on PLA or PLA/MWCNT samples. The results show a clear effect on the cell membrane potential, depending on the underlying substrate.
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Affiliation(s)
- Giulia Suarato
- Istituto
Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Samuel Pressi
- Department
of Chemical Sciences, University of Padua, via Marzolo 1, 35131 Padova, Italy
- Interdepartmental
Centre Giorgio Levi Cases for Energy Economics and Technology, University of Padua, via Marzolo 9, 35131 Padova, Italy
| | - Enzo Menna
- Department
of Chemical Sciences, University of Padua, via Marzolo 1, 35131 Padova, Italy
- Interdepartmental
Centre Giorgio Levi Cases for Energy Economics and Technology, University of Padua, via Marzolo 9, 35131 Padova, Italy
| | - Massimo Ruben
- Istituto
Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | | | - Andrea Barberis
- Istituto
Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Dalila Miele
- Department
of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Giuseppina Sandri
- Department
of Drug Sciences, University of Pavia, via Taramelli 12, 27100 Pavia, Italy
| | - Marco Salerno
- Istituto
Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Andrea Schirato
- Istituto
Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- Dipartimento
di Fisica, Politecnico di Milano, Pizza Leonardo da Vinci 32, Milan 20133, Italy
- Department
of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Alessandro Alabastri
- Department
of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
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11
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Venkatesan N, Doskey LC, Malhi H. The Role of Endoplasmic Reticulum in Lipotoxicity during Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) Pathogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1887-1899. [PMID: 37689385 PMCID: PMC10699131 DOI: 10.1016/j.ajpath.2023.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 09/11/2023]
Abstract
Perturbations in lipid and protein homeostasis induce endoplasmic reticulum (ER) stress in metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease. Lipotoxic and proteotoxic stress can activate the unfolded protein response (UPR) transducers: inositol requiring enzyme1α, PKR-like ER kinase, and activating transcription factor 6α. Collectively, these pathways induce expression of genes that encode functions to resolve the protein folding defect and ER stress by increasing the protein folding capacity of the ER and degradation of misfolded proteins. The ER is also intimately connected with lipid metabolism, including de novo ceramide synthesis, phospholipid and cholesterol synthesis, and lipid droplet formation. Following their activation, the UPR transducers also regulate lipogenic pathways in the liver. With persistent ER stress, cellular adaptation fails, resulting in hepatocyte apoptosis, a pathological marker of liver disease. In addition to the ER-nucleus signaling activated by the UPR, the ER can interact with other organelles via membrane contact sites. Modulating intracellular communication between ER and endosomes, lipid droplets, and mitochondria to restore ER homeostasis could have therapeutic efficacy in ameliorating liver disease. Recent studies have also demonstrated that cells can convey ER stress by the release of extracellular vesicles. This review discusses lipotoxic ER stress and the central role of the ER in communicating ER stress to other intracellular organelles in MASLD pathogenesis.
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Affiliation(s)
- Nanditha Venkatesan
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Luke C Doskey
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Harmeet Malhi
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota.
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12
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Will I, Attardo GM, de Bekker C. Multiomic interpretation of fungus-infected ant metabolomes during manipulated summit disease. Sci Rep 2023; 13:14363. [PMID: 37658067 PMCID: PMC10474057 DOI: 10.1038/s41598-023-40065-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/03/2023] [Indexed: 09/03/2023] Open
Abstract
Camponotus floridanus ants show altered behaviors followed by a fatal summiting phenotype when infected with manipulating Ophiocordyceps camponoti-floridani fungi. Host summiting as a strategy to increase transmission is also observed with parasite taxa beyond fungi, including aquatic and terrestrial helminths and baculoviruses. The drastic phenotypic changes can sometimes reflect significant molecular changes in gene expression and metabolite concentrations measured in manipulated hosts. Nevertheless, the underlying mechanisms still need to be fully characterized. To investigate the small molecules producing summiting behavior, we infected C. floridanus ants with O. camponoti-floridani and sampled their heads for LC-MS/MS when we observed the characteristic summiting phenotype. We link this metabolomic data with our previous genomic and transcriptomic data to propose mechanisms that underlie manipulated summiting behavior in "zombie ants." This "multiomic" evidence points toward the dysregulation of neurotransmitter levels and neuronal signaling. We propose that these processes are altered during infection and manipulation based on (1) differential expression of neurotransmitter synthesis and receptor genes, (2) altered abundance of metabolites and neurotransmitters (or their precursors) with known behavioral effects in ants and other insects, and (3) possible suppression of a connected immunity pathway. We additionally report signals for metabolic activity during manipulation related to primary metabolism, detoxification, and anti-stress protectants. Taken together, these findings suggest that host manipulation is likely a multi-faceted phenomenon, with key processes changing at multiple levels of molecular organization.
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Affiliation(s)
- I Will
- Biology Department, University of Central Florida, Orlando, USA.
| | - G M Attardo
- Entomology and Nematology Department, University of California-Davis, Davis, USA
| | - C de Bekker
- Biology Department, University of Central Florida, Orlando, USA.
- Biology Department, Utrecht University, Utrecht, The Netherlands.
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13
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Turk SM, Indovina CJ, Miller JM, Overton DL, Runnebohm AM, Orchard CJ, Tragesser-Tiña ME, Gosser SK, Doss EM, Richards KA, Irelan CB, Daraghmi MM, Bailey CG, Niekamp JM, Claypool KP, Engle SM, Buchanan BW, Woodruff KA, Olesen JB, Smaldino PJ, Rubenstein EM. Lipid biosynthesis perturbation impairs endoplasmic reticulum-associated degradation. J Biol Chem 2023; 299:104939. [PMID: 37331602 PMCID: PMC10372827 DOI: 10.1016/j.jbc.2023.104939] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/02/2023] [Accepted: 06/09/2023] [Indexed: 06/20/2023] Open
Abstract
The relationship between lipid homeostasis and protein homeostasis (proteostasis) is complex and remains incompletely understood. We conducted a screen for genes required for efficient degradation of Deg1-Sec62, a model aberrant translocon-associated substrate of the endoplasmic reticulum (ER) ubiquitin ligase Hrd1, in Saccharomyces cerevisiae. This screen revealed that INO4 is required for efficient Deg1-Sec62 degradation. INO4 encodes one subunit of the Ino2/Ino4 heterodimeric transcription factor, which regulates expression of genes required for lipid biosynthesis. Deg1-Sec62 degradation was also impaired by mutation of genes encoding several enzymes mediating phospholipid and sterol biosynthesis. The degradation defect in ino4Δ yeast was rescued by supplementation with metabolites whose synthesis and uptake are mediated by Ino2/Ino4 targets. Stabilization of a panel of substrates of the Hrd1 and Doa10 ER ubiquitin ligases by INO4 deletion indicates ER protein quality control is generally sensitive to perturbed lipid homeostasis. Loss of INO4 sensitized yeast to proteotoxic stress, suggesting a broad requirement for lipid homeostasis in maintaining proteostasis. A better understanding of the dynamic relationship between lipid homeostasis and proteostasis may lead to improved understanding and treatment of several human diseases associated with altered lipid biosynthesis.
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Affiliation(s)
- Samantha M Turk
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | | | - Jacob M Miller
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | | | | | - Cade J Orchard
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | | | | | - Ellen M Doss
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | - Kyle A Richards
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | | | | | - Connor G Bailey
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | - Julia M Niekamp
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | | | - Sarah M Engle
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | - Bryce W Buchanan
- Department of Biology, Ball State University, Muncie, Indiana, USA
| | | | - James B Olesen
- Department of Biology, Ball State University, Muncie, Indiana, USA
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14
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Celik C, Lee SYT, Yap WS, Thibault G. Endoplasmic reticulum stress and lipids in health and diseases. Prog Lipid Res 2023; 89:101198. [PMID: 36379317 DOI: 10.1016/j.plipres.2022.101198] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/03/2022] [Accepted: 11/09/2022] [Indexed: 11/14/2022]
Abstract
The endoplasmic reticulum (ER) is a complex and dynamic organelle that regulates many cellular pathways, including protein synthesis, protein quality control, and lipid synthesis. When one or multiple ER roles are dysregulated and saturated, the ER enters a stress state, which, in turn, activates the highly conserved unfolded protein response (UPR). By sensing the accumulation of unfolded proteins or lipid bilayer stress (LBS) at the ER, the UPR triggers pathways to restore ER homeostasis and eventually induces apoptosis if the stress remains unresolved. In recent years, it has emerged that the UPR works intimately with other cellular pathways to maintain lipid homeostasis at the ER, and so does at cellular levels. Lipid distribution, along with lipid anabolism and catabolism, are tightly regulated, in part, by the ER. Dysfunctional and overwhelmed lipid-related pathways, independently or in combination with ER stress, can have reciprocal effects on other cellular functions, contributing to the development of diseases. In this review, we summarize the current understanding of the UPR in response to proteotoxic stress and LBS and the breadth of the functions mitigated by the UPR in different tissues and in the context of diseases.
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Affiliation(s)
- Cenk Celik
- School of Biological Sciences, Nanyang Technological University, Singapore
| | | | - Wei Sheng Yap
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore; Mechanobiology Institute, National University of Singapore, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore.
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15
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Farzana F, McConville MJ, Renoir T, Li S, Nie S, Tran H, Hannan AJ, Hatters DM, Boughton BA. Longitudinal spatial mapping of lipid metabolites reveals pre-symptomatic changes in the hippocampi of Huntington's disease transgenic mice. Neurobiol Dis 2023; 176:105933. [PMID: 36436748 DOI: 10.1016/j.nbd.2022.105933] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/16/2022] [Accepted: 11/23/2022] [Indexed: 11/26/2022] Open
Abstract
In Huntington's disease (HD), a key pathological feature includes the development of inclusion-bodies of fragments of the mutant huntingtin protein in the neurons of the striatum and hippocampus. To examine the molecular changes associated with inclusion-body formation, we applied MALDI-mass spectrometry imaging and deuterium pulse labelling to determine lipid levels and synthesis rates in the hippocampus of a transgenic mouse model of HD (R6/1 line). The R6/1 HD mice lacked inclusions in the hippocampus at 6 weeks of age (pre-symptomatic), whereas inclusions were pervasive by 16 weeks of age (symptomatic). Hippocampal subfields (CA1, CA3 and DG), which formed the highest density of inclusion formation in the mouse brain showed a reduction in the relative abundance of neuron-enriched lipids that have roles in neurotransmission, synaptic plasticity, neurogenesis, and ER-stress protection. Lipids involved in the adaptive response to ER stress (phosphatidylinositol, phosphatidic acid, and ganglioside classes) displayed increased rates of synthesis in HD mice relative to WT mice at all the ages examined, including prior to the formation of the inclusion bodies. Our findings, therefore, support a role for ER stress occurring pre-symptomatically and potentially contributing to pathological mechanisms underlying HD.
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Affiliation(s)
- Farheen Farzana
- Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Victoria 3010, Australia; Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Malcolm J McConville
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia; Metabolomics Australia, The University of Melbourne, Victoria 3010, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Shanshan Li
- Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Shuai Nie
- Melbourne Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Harvey Tran
- Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Victoria 3010, Australia.
| | - Danny M Hatters
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia.
| | - Berin A Boughton
- School of Biosciences, The University of Melbourne, Victoria 3010, Australia; Australian National Phenome Centre, Murdoch University, Murdoch 6150, Western Australia, Australia.
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16
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Luo Y, Jiao Q, Chen Y. Targeting endoplasmic reticulum stress-the responder to lipotoxicity and modulator of non-alcoholic fatty liver diseases. Expert Opin Ther Targets 2022; 26:1073-1085. [PMID: 36657744 DOI: 10.1080/14728222.2022.2170780] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Endoplasmic reticulum (ER) stress occurs with aberrant lipid accumulation and resultant adverse effects and widely exists in nonalcoholic fatty liver disease (NAFLD). It triggers the unfolded protein response (UPR) to restore ER homeostasis and actively participates in NAFLD pathological processes, including hepatic steatosis, inflammation, hepatocyte death, and fibrosis. Such acknowledges drive the discovery of novel NAFLD biomarker and therapeutic targets and the development of ER-stress targeted NAFLD drugs. AREAS COVERED This article discusses and updates the role of ER stress and UPR in NAFLD, the underlying action mechanism, and especially their full participation in NAFLD pathophysiology. It characterizes key molecular targets useful for the prevention and treatment of NAFLD and highlights the recent ER stress-targeted therapeutic strategies for NAFLD. EXPERT OPINION Targeting ER Stress is a valuable and promising strategy for NAFLD treatment, but its smooth translation into clinical application still requires better clarification of the different UPR patterns in diverse NAFLD physiological states. Further understanding of the distinct effects of these various patterns on NAFLD, the thresholds deciding their final impacts, and their actions via non-liver tissues and cells would be of great help to develop a precise and effective therapy for NAFLD. [Figure: see text].
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Affiliation(s)
- Yu Luo
- School of Pharmaceutical Science, University of South China, Hengyang, Hunan, China
| | - Qiangqiang Jiao
- School of Pharmaceutical Science, University of South China, Hengyang, Hunan, China
| | - Yuping Chen
- School of Pharmaceutical Science, University of South China, Hengyang, Hunan, China.,Institute of Pharmacy & Pharmacology, University of South China, Hengyang, Hunan, China
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17
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Gómez-Mellado VE, Chang JC, Ho-Mok KS, Bernardino Morcillo C, Kersten RHJ, Oude Elferink RPJ, Verhoeven AJ, Paulusma CC. ATP8B1 Deficiency Results in Elevated Mitochondrial Phosphatidylethanolamine Levels and Increased Mitochondrial Oxidative Phosphorylation in Human Hepatoma Cells. Int J Mol Sci 2022; 23:ijms232012344. [PMID: 36293199 PMCID: PMC9604224 DOI: 10.3390/ijms232012344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/20/2022] Open
Abstract
ATP8B1 is a phospholipid flippase that is deficient in patients with progressive familial intrahepatic cholestasis type 1 (PFIC1). PFIC1 patients suffer from severe liver disease but also present with dyslipidemia, including low plasma cholesterol, of yet unknown etiology. Here we show that ATP8B1 knockdown in HepG2 cells leads to a strong increase in the mitochondrial oxidative phosphorylation (OXPHOS) without a change in glycolysis. The enhanced OXPHOS coincides with elevated low-density lipoprotein receptor protein and increased mitochondrial fragmentation and phosphatidylethanolamine levels. Furthermore, expression of phosphatidylethanolamine N-methyltransferase, an enzyme that catalyzes the conversion of mitochondrial-derived phosphatidylethanolamine to phosphatidylcholine, was reduced in ATP8B1 knockdown cells. We conclude that ATP8B1 deficiency results in elevated mitochondrial PE levels that stimulate mitochondrial OXPHOS. The increased OXPHOS leads to elevated LDLR levels, which provides a possible explanation for the reduced plasma cholesterol levels in PFIC1 disease.
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Affiliation(s)
- Valentina E. Gómez-Mellado
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Jung-Chin Chang
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Kam S. Ho-Mok
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Carmen Bernardino Morcillo
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
| | - Remco H. J. Kersten
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Ronald P. J. Oude Elferink
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Arthur J. Verhoeven
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Coen C. Paulusma
- Amsterdam UMC, University of Amsterdam, Tytgat Institute for Liver and Intestinal Research, Meibergdreef 69, 1105 BK Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, 1105 AZ Amsterdam, The Netherlands
- Correspondence:
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18
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Hamdan MF, Lung SC, Guo ZH, Chye ML. Roles of acyl-CoA-binding proteins in plant reproduction. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2918-2936. [PMID: 35560189 DOI: 10.1093/jxb/erab499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 11/11/2021] [Indexed: 06/15/2023]
Abstract
Acyl-CoA-binding proteins (ACBPs) constitute a well-conserved family of proteins in eukaryotes that are important in stress responses and development. Past studies have shown that ACBPs are involved in maintaining, transporting and protecting acyl-CoA esters during lipid biosynthesis in plants, mammals, and yeast. ACBPs show differential expression and various binding affinities for acyl-CoA esters. Hence, ACBPs can play a crucial part in maintaining lipid homeostasis. This review summarizes the functions of ACBPs during the stages of reproduction in plants and other organisms. A comprehensive understanding on the roles of ACBPs during plant reproduction may lead to opportunities in crop improvement in agriculture.
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Affiliation(s)
- Mohd Fadhli Hamdan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Shiu-Cheung Lung
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ze-Hua Guo
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
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19
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Lipid Dyshomeostasis and Inherited Cerebellar Ataxia. Mol Neurobiol 2022; 59:3800-3828. [PMID: 35420383 PMCID: PMC9148275 DOI: 10.1007/s12035-022-02826-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/01/2022] [Indexed: 12/04/2022]
Abstract
Cerebellar ataxia is a form of ataxia that originates from dysfunction of the cerebellum, but may involve additional neurological tissues. Its clinical symptoms are mainly characterized by the absence of voluntary muscle coordination and loss of control of movement with varying manifestations due to differences in severity, in the site of cerebellar damage and in the involvement of extracerebellar tissues. Cerebellar ataxia may be sporadic, acquired, and hereditary. Hereditary ataxia accounts for the majority of cases. Hereditary ataxia has been tentatively divided into several subtypes by scientists in the field, and nearly all of them remain incurable. This is mainly because the detailed mechanisms of these cerebellar disorders are incompletely understood. To precisely diagnose and treat these diseases, studies on their molecular mechanisms have been conducted extensively in the past. Accumulating evidence has demonstrated that some common pathogenic mechanisms exist within each subtype of inherited ataxia. However, no reports have indicated whether there is a common mechanism among the different subtypes of inherited cerebellar ataxia. In this review, we summarize the available references and databases on neurological disorders characterized by cerebellar ataxia and show that a subset of genes involved in lipid homeostasis form a new group that may cause ataxic disorders through a common mechanism. This common signaling pathway can provide a valuable reference for future diagnosis and treatment of ataxic disorders.
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20
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Ishiwata-Kimata Y, Le QG, Kimata Y. Induction and Aggravation of the Endoplasmic-Reticulum Stress by Membrane-Lipid Metabolic Intermediate Phosphatidyl- N-Monomethylethanolamine. Front Cell Dev Biol 2022; 9:743018. [PMID: 35071223 PMCID: PMC8770322 DOI: 10.3389/fcell.2021.743018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Phosphatidylcholine (PC) is produced via two distinct pathways in both hepatocytes and yeast, Saccharomyces cerevisiae. One of these pathways involves the sequential methylation of phosphatidylethanolamine (PE). In yeast cells, the methyltransferase, Cho2, converts PE to phosphatidylmonomethylethanolamine (PMME), which is further modified to PC by another methyltransferase, Opi3. On the other hand, free choline is utilized for PC production via the Kennedy pathway. The blockage of PC production is well known to cause endoplasmic reticulum (ER) stress and activate the ER-stress sensor, Ire1, to induce unfolded protein response (UPR). Here, we demonstrate that even when free choline is sufficiently supplied, the opi3Δ mutation, but not the cho2 Δ mutation, induces the UPR. The UPR was also found to be induced by CHO2 overexpression. Further, monomethylethanolamine, which is converted to PMME probably through the Kennedy pathway, caused or potentiated ER stress in both mammalian and yeast cells. We thus deduce that PMME per se is an ER-stressing molecule. Interestingly, spontaneously accumulated PMME seemed to aggravate ER stress in yeast cells. Collectively, our findings demonstrate the multiple detrimental effects of the low-abundance phospholipid species, PMME.
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Affiliation(s)
- Yuki Ishiwata-Kimata
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Japan
| | - Quynh Giang Le
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Japan
| | - Yukio Kimata
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Japan
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21
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Reduced DNAJC3 Expression Affects Protein Translocation across the ER Membrane and Attenuates the Down-Modulating Effect of the Translocation Inhibitor Cyclotriazadisulfonamide. Int J Mol Sci 2022; 23:ijms23020584. [PMID: 35054769 PMCID: PMC8775681 DOI: 10.3390/ijms23020584] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 12/20/2022] Open
Abstract
One of the reported substrates for the endoplasmic reticulum (ER) translocation inhibitor cyclotriazadisulfonamide (CADA) is DNAJC3, a chaperone of the unfolded protein response during ER stress. In this study, we investigated the impact of altered DNAJC3 protein levels on the inhibitory activity of CADA. By comparing WT DNAJC3 with a CADA-resistant DNAJC3 mutant, we observed the enhanced sensitivity of human CD4, PTK7 and ERLEC1 for CADA when DNAJC3 was expressed at high levels. Combined treatment of CADA with a proteasome inhibitor resulted in synergistic inhibition of protein translocation and in the rescue of a small preprotein fraction, which presumably corresponds to the CADA affected protein fraction that is stalled at the Sec61 translocon. We demonstrate that DNAJC3 enhances the protein translation of a reporter protein that is expressed downstream of the CADA-stalled substrate, suggesting that DNAJC3 promotes the clearance of the clogged translocon. We propose a model in which a reduced DNAJC3 level by CADA slows down the clearance of CADA-stalled substrates. This results in higher residual translocation into the ER lumen due to the longer dwelling time of the temporarily stalled substrates in the translocon. Thus, by directly reducing DNAJC3 protein levels, CADA attenuates its net down-modulating effect on its substrates.
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22
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Vial T, Marti G, Missé D, Pompon J. Lipid Interactions Between Flaviviruses and Mosquito Vectors. Front Physiol 2021; 12:763195. [PMID: 34899388 PMCID: PMC8660100 DOI: 10.3389/fphys.2021.763195] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 09/20/2021] [Indexed: 11/18/2022] Open
Abstract
Mosquito-borne flaviviruses, such as dengue (DENV), Zika (ZIKV), yellow fever (YFV), West Nile (WNV), and Japanese encephalitis (JEV) viruses, threaten a large part of the human populations. In absence of therapeutics and effective vaccines against each flaviviruses, targeting viral metabolic requirements in mosquitoes may hold the key to new intervention strategies. Development of metabolomics in the last decade opened a new field of research: mosquito metabolomics. It is now clear that flaviviruses rely on mosquito lipids, especially phospholipids, for their cellular cycle and propagation. Here, we review the biosyntheses of, biochemical properties of and flaviviral interactions with mosquito phospholipids. Phospholipids are structural lipids with a polar headgroup and apolar acyl chains, enabling the formation of lipid bilayer that form plasma- and endomembranes. Phospholipids are mostly synthesized through the de novo pathway and remodeling cycle. Variations in headgroup and acyl chains influence phospholipid physicochemical properties and consequently the membrane behavior. Flaviviruses interact with cellular membranes at every step of their cellular cycle. Recent evidence demonstrates that flaviviruses reconfigure the phospholipidome in mosquitoes by regulating phospholipid syntheses to increase virus multiplication. Identifying the phospholipids involved and understanding how flaviviruses regulate these in mosquitoes is required to design new interventions.
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Affiliation(s)
- Thomas Vial
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.,UMR 152 PHARMADEV-IRD, Université Paul Sabatier, Toulouse, France
| | - Guillaume Marti
- LRSV (UMR 5546), CNRS, Université de Toulouse, Toulouse, France.,MetaboHUB, National Infrastructure of Metabolomics and Fluxomics, Toulouse, France
| | - Dorothée Missé
- MIVEGEC, Université Montpellier, IRD, CNRS, Montpellier, France
| | - Julien Pompon
- MIVEGEC, Université Montpellier, IRD, CNRS, Montpellier, France
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23
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Dai Y, Tang H, Pang S. The Crucial Roles of Phospholipids in Aging and Lifespan Regulation. Front Physiol 2021; 12:775648. [PMID: 34887779 PMCID: PMC8650052 DOI: 10.3389/fphys.2021.775648] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/19/2021] [Indexed: 01/04/2023] Open
Abstract
Phospholipids are major membrane lipids that consist of lipid bilayers. This basic cellular structure acts as a barrier to protect the cell against various environmental insults and more importantly, enables multiple cellular processes to occur in subcellular compartments. Numerous studies have linked the complexity of membrane lipids to signal transductions, organelle functions, as well as physiological processes, and human diseases. Recently, crucial roles for membrane lipids in the aging process are beginning to emerge. In this study, we summarized current advances in our understanding of the relationship between membrane lipids and aging with an emphasis on phospholipid species. We surveyed how major phospholipid species change with age in different organisms and tissues, and some common patterns of membrane lipid change during aging were proposed. Further, the functions of different phospholipid molecules in regulating healthspan and lifespan, as well as their potential mechanisms of action, were also discussed.
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Affiliation(s)
- Yucan Dai
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Haiqing Tang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Shanshan Pang
- School of Life Sciences, Chongqing University, Chongqing, China
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24
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Lv X, Jin K, Sun G, Ledesma-Amaro R, Liu L. Microscopy imaging of living cells in metabolic engineering. Trends Biotechnol 2021; 40:752-765. [PMID: 34799183 DOI: 10.1016/j.tibtech.2021.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 01/23/2023]
Abstract
Microscopy imaging of living cells is becoming a pivotal, noninvasive, and highly specific tool in metabolic engineering to visualize molecular dynamics in industrial microorganisms. This review describes the different microscopy methods, from fluorescence to super resolution, with application in microbial bioengineering. Firstly, the role and importance of microscopy imaging is analyzed in the context of strain design. Then, the advantages and disadvantages of different microscopy technologies are discussed, including confocal laser scanning microscopy (CLSM), spatial light interference microscopy (SLIM), and super-resolution microscopy, followed by their applications in synthetic biology. Finally, the future perspectives of live-cell imaging and their potential to transform microbial systems are analyzed. This review provides theoretical guidance and highlights the importance of microscopy in understanding and engineering microbial metabolism.
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Affiliation(s)
- Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
| | - Ke Jin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
| | - Guoyun Sun
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London SW72AZ, UK
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China.
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25
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The Unfolded Protein Response as a Guardian of the Secretory Pathway. Cells 2021; 10:cells10112965. [PMID: 34831188 PMCID: PMC8616143 DOI: 10.3390/cells10112965] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is the major site of membrane biogenesis in most eukaryotic cells. As the entry point to the secretory pathway, it handles more than 10,000 different secretory and membrane proteins. The insertion of proteins into the membrane, their folding, and ER exit are affected by the lipid composition of the ER membrane and its collective membrane stiffness. The ER is also a hotspot of lipid biosynthesis including sterols, glycerophospholipids, ceramides and neural storage lipids. The unfolded protein response (UPR) bears an evolutionary conserved, dual sensitivity to both protein-folding imbalances in the ER lumen and aberrant compositions of the ER membrane, referred to as lipid bilayer stress (LBS). Through transcriptional and non-transcriptional mechanisms, the UPR upregulates the protein folding capacity of the ER and balances the production of proteins and lipids to maintain a functional secretory pathway. In this review, we discuss how UPR transducers sense unfolded proteins and LBS with a particular focus on their role as guardians of the secretory pathway.
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26
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Robinson BP, Hawbaker S, Chiang A, Jordahl EM, Anaokar S, Nikiforov A, Bowman RW, Ziegler P, McAtee CK, Patton-Vogt J, O'Donnell AF. Alpha-arrestins Aly1/Art6 and Aly2/Art3 regulate trafficking of the glycerophosphoinositol transporter Git1 and impact phospholipid homeostasis. Biol Cell 2021; 114:3-31. [PMID: 34562280 DOI: 10.1111/boc.202100007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/23/2021] [Accepted: 07/15/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND INFORMATION Phosphatidylinositol (PI) is an essential phospholipid, critical to membrane bilayers. The complete deacylation of PI by B-type phospholipases produces intracellular and extracellular glycerophosphoinositol (GPI). Extracellular GPI is transported into the cell via Git1, a member of the Major Facilitator Superfamily of transporters at the yeast plasma membrane. Internalized GPI is degraded to produce inositol, phosphate and glycerol, thereby contributing to these pools. GIT1 gene expression is controlled by nutrient balance, with phosphate or inositol starvation increasing GIT1 expression to stimulate GPI uptake. However, less is known about control of Git1 protein levels or localization. RESULTS We find that the α-arrestins, an important class of protein trafficking adaptor, regulate Git1 localization and this is dependent upon their interaction with the ubiquitin ligase Rsp5. Specifically, α-arrestin Aly2 stimulates Git1 trafficking to the vacuole under basal conditions, but in response to GPI-treatment, either Aly1 or Aly2 promote Git1 vacuole trafficking. Cell surface retention of Git1, as occurs in aly1∆ aly2∆ cells, is linked to impaired growth in the presence of exogenous GPI and results in increased uptake of radiolabeled GPI, suggesting that accumulation of GPI somehow causes cellular toxicity. Regulation of α-arrestin Aly1 by the protein phosphatase calcineurin improves steady-state and substrate-induced trafficking of Git1, however, calcineurin plays a larger role in Git1 trafficking beyond regulation of α-arrestins. Interestingly, loss of Aly1 and Aly2 increased phosphatidylinositol-3-phosphate on the limiting membrane of the vacuole, and this was further exacerbated by GPI addition, suggesting that the effect is partially linked to Git1. Loss of Aly1 and Aly2 leads to increased incorporation of inositol label from [3 H]-inositol-labelled GPI into PI, confirming that internalized GPI influences PI balance and indicating a role for the a-arrestins in this regulation. CONCLUSIONS The α-arrestins Aly1 and Aly2 are novel regulators of Git1 trafficking with previously unanticipated roles in controlling phospholipid distribution and balance. SIGNIFICANCE To our knowledge, this is the first example of α-arrestin regulation of phosphatidyliniositol-3-phosphate levels. In future studies it will be exciting to determine if other α-arrestins similarly alter PI and PIPs to change the cellular landscape.
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Affiliation(s)
- Benjamin P Robinson
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Sarah Hawbaker
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Annette Chiang
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Eric M Jordahl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sanket Anaokar
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Alexiy Nikiforov
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Ray W Bowman
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Philip Ziegler
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Ceara K McAtee
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Allyson F O'Donnell
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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27
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The fatty acid elongase ELOVL6 regulates bortezomib resistance in multiple myeloma. Blood Adv 2021; 5:1933-1946. [PMID: 33821992 DOI: 10.1182/bloodadvances.2020002578] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 02/10/2021] [Indexed: 12/24/2022] Open
Abstract
Resistance to the proteasome inhibitor bortezomib (BTZ) represents a major obstacle in the treatment of multiple myeloma (MM). The contribution of lipid metabolism in the resistance of MM cells to BTZ is mostly unknown. Here we report that levels of fatty acid elongase 6 (ELOVL6) were lower in MM cells from BTZ-nonresponsive vs BTZ-responsive patients and in cultured MM cells selected for BTZ resistance compared with parental counterparts. Accordingly, depletion of ELOVL6 in parental MM cells suppressed BTZ-induced endoplasmic reticulum (ER) stress and cytotoxicity, whereas restoration of ELOVL6 levels in BTZ-resistant MM cells sensitized them to BTZ in tissue culture settings and, as xenografts, in a plasmacytoma mouse model. Furthermore, for the first time, we identified changes in the BTZ-induced lipidome between parental and BTZ-resistant MM cell lines underlying a functional difference in their response to BTZ. We demonstrated that restoration of ELOVL6 levels in BTZ-resistant MM cells resensitized them to BTZ largely via upregulation of ELOVL6-dependent ceramide species, which was a prerequisite for BTZ-induced ER stress and cell death in these cells. Our data characterize ELOVL6 as a major clinically relevant regulator of MM cell resistance to BTZ, which can emerge from the impaired ability of these cells to alter ceramide composition in response to BTZ.
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28
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Kumar V, Maity S. ER Stress-Sensor Proteins and ER-Mitochondrial Crosstalk-Signaling Beyond (ER) Stress Response. Biomolecules 2021; 11:173. [PMID: 33525374 PMCID: PMC7911976 DOI: 10.3390/biom11020173] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/14/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023] Open
Abstract
Recent studies undoubtedly show the importance of inter organellar connections to maintain cellular homeostasis. In normal physiological conditions or in the presence of cellular and environmental stress, each organelle responds alone or in coordination to maintain cellular function. The Endoplasmic reticulum (ER) and mitochondria are two important organelles with very specialized structural and functional properties. These two organelles are physically connected through very specialized proteins in the region called the mitochondria-associated ER membrane (MAM). The molecular foundation of this relationship is complex and involves not only ion homeostasis through the shuttling of calcium but also many structural and apoptotic proteins. IRE1alpha and PERK are known for their canonical function as an ER stress sensor controlling unfolded protein response during ER stress. The presence of these transmembrane proteins at the MAM indicates its potential involvement in other biological functions beyond ER stress signaling. Many recent studies have now focused on the non-canonical function of these sensors. In this review, we will focus on ER mitochondrial interdependence with special emphasis on the non-canonical role of ER stress sensors beyond ER stress.
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29
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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.
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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
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30
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Deng J, Bai X, Tang H, Pang S. DNA damage promotes ER stress resistance through elevation of unsaturated phosphatidylcholine in Caenorhabditis elegans. J Biol Chem 2021; 296:100095. [PMID: 33208465 PMCID: PMC7949029 DOI: 10.1074/jbc.ra120.016083] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/10/2020] [Accepted: 11/18/2020] [Indexed: 01/04/2023] Open
Abstract
DNA damage triggers the cellular adaptive response to arrest proliferation and repair DNA damage; when damage is too severe to be repaired, apoptosis is initiated to prevent the spread of genomic insults. However, how cells endure DNA damage to maintain cell function remains largely unexplored. By using Caenorhabditis elegans as a model, we report that DNA damage elicits cell maintenance programs, including the unfolded protein response of the endoplasmic reticulum (UPRER). Mechanistically, sublethal DNA damage unexpectedly suppresses apoptotic genes in C. elegans, which in turn increases the activity of the inositol-requiring enzyme 1/X-box binding protein 1 (IRE-1/XBP-1) branch of the UPRER by elevating unsaturated phosphatidylcholine. In addition, UPRER activation requires silencing of the lipid regulator skinhead-1 (SKN-1). DNA damage suppresses SKN-1 activity to increase unsaturated phosphatidylcholine and activate UPRER. These findings reveal the UPRER activation as an organismal adaptive response that is important to maintain cell function during DNA damage.
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Affiliation(s)
- Jianhui Deng
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Xue Bai
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Haiqing Tang
- School of Life Sciences, Chongqing University, Chongqing, China.
| | - Shanshan Pang
- School of Life Sciences, Chongqing University, Chongqing, China.
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31
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Jiang H. Quality control pathways of tail-anchored proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118922. [PMID: 33285177 DOI: 10.1016/j.bbamcr.2020.118922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/14/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022]
Abstract
Tail-anchored (TA) proteins have an N-terminal domain in the cytosol and a C-terminal transmembrane domain anchored to a variety of organelle membranes. TA proteins are recognized by targeting factors at the transmembrane domain and C-terminal sequence and are guided to distinct membranes. The promiscuity of targeting sequences and the dysfunction of targeting pathways cause mistargeting of TA proteins. TA proteins are under surveillance by quality control pathways. For resident TA proteins at mitochondrial and ER membranes, intrinsic instability or stimuli induced degrons of the cytosolic and transmembrane domains are sensed by quality control factors to initiate degradation of TA proteins. These pathways are summarized as TA protein degradation-Cytosol (TAD-C) and TAD-Membrane (TAD-M) pathways. For mistargeted and a subset of solitary TA proteins at mitochondrial and peroxisomal membranes, a unique pathway has been revealed in recent years. Msp1/ATAD1 is an AAA-ATPase dually-localized to mitochondrial and peroxisomal membranes. It directly recognizes mistargeted and solitary TA proteins and dislocates them out of membrane. Dislocated substrates are subsequently ubiquitinated by the ER-resident Doa10 ubiquitin E3 ligase complex for degradation. We summarize and discuss the substrate recognition, dislocation and degradation mechanisms of the Msp1 pathway.
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Affiliation(s)
- Hui Jiang
- National Institute of Biological Sciences, Beijing 102206, China; Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100871, China.
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32
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Yap WS, Shyu P, Gaspar ML, Jesch SA, Marvalim C, Prinz WA, Henry SA, Thibault G. The yeast FIT2 homologs are necessary to maintain cellular proteostasis and membrane lipid homeostasis. J Cell Sci 2020; 133:jcs248526. [PMID: 33033181 PMCID: PMC7657468 DOI: 10.1242/jcs.248526] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022] Open
Abstract
Lipid droplets (LDs) are implicated in conditions of lipid and protein dysregulation. The fat storage-inducing transmembrane (FIT; also known as FITM) family induces LD formation. Here, we establish a model system to study the role of the Saccharomyces cerevisiae FIT homologues (ScFIT), SCS3 and YFT2, in the proteostasis and stress response pathways. While LD biogenesis and basal endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) remain unaltered in ScFIT mutants, SCS3 was found to be essential for proper stress-induced UPR activation and for viability in the absence of the sole yeast UPR transducer IRE1 Owing to not having a functional UPR, cells with mutated SCS3 exhibited an accumulation of triacylglycerol within the ER along with aberrant LD morphology, suggesting that there is a UPR-dependent compensatory mechanism that acts to mitigate lack of SCS3 Additionally, SCS3 was necessary to maintain phospholipid homeostasis. Strikingly, global protein ubiquitylation and the turnover of both ER and cytoplasmic misfolded proteins is impaired in ScFITΔ cells, while a screen for interacting partners of Scs3 identifies components of the proteostatic machinery as putative targets. Together, our data support a model where ScFITs play an important role in lipid metabolism and proteostasis beyond their defined roles in LD biogenesis.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Wei Sheng Yap
- School of Biological Sciences Nanyang Technological University, Singapore, 637551
| | - Peter Shyu
- School of Biological Sciences Nanyang Technological University, Singapore, 637551
| | - Maria Laura Gaspar
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Stephen A Jesch
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Charlie Marvalim
- School of Biological Sciences Nanyang Technological University, Singapore, 637551
| | - William A Prinz
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Susan A Henry
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Guillaume Thibault
- School of Biological Sciences Nanyang Technological University, Singapore, 637551
- Institute of Molecular and Cell Biology, A*STAR, Singapore, 138673
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33
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Laganà AS, Unfer V, Garzon S, Bizzarri M. Role of inositol to improve surfactant functions and reduce IL-6 levels: A potential adjuvant strategy for SARS-CoV-2 pneumonia? Med Hypotheses 2020; 144:110262. [PMID: 33254564 PMCID: PMC7480225 DOI: 10.1016/j.mehy.2020.110262] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 08/30/2020] [Accepted: 09/05/2020] [Indexed: 01/18/2023]
Abstract
To date, the spread of SARS-CoV-2 infection is increasing worldwide and represents a primary healthcare emergency. Although the infection can be asymptomatic, several cases develop severe pneumonia and acute respiratory distress syndrome (ARDS) characterized by high levels of pro-inflammatory cytokines, primarily interleukin (IL)-6. Based on available data, the severity of ARDS and serum levels of IL-6 are key determinants for the prognosis. In this scenario, available in vitro and in vivo data suggested that myo-inositol is able to increase the synthesis and function of the surfactant phosphatidylinositol, acting on the phosphoinositide 3-kinase (PI3K)-regulated signaling, with amelioration of both immune system and oxygenation at the bronchoalveolar level. In addition, myo-inositol has been found able to decrease the levels of IL-6 in several experimental settings, due to an effect on the inositol-requiring enzyme 1 (IRE1)-X-box-binding protein 1 (XBP1) and on the signal transducer and activator of transcription 3 (STAT3) pathways. In this scenario, treatment with myo-inositol may be able to reduce IL-6 dependent inflammatory response and improve oxygenation in patients with severe ARDS by SARS-CoV-2. In addition, the action of myo-inositol on IRE1 endonuclease activity may also inhibit the replication of SARS-CoV-2, as was reported for the respiratory syncytial virus. Since the available data are extremely limited, if this potential therapeutic approach will be considered valid in the clinical practice, the necessary future investigations should aim to identify the best dose, administration route (oral, intravenous and/or aerosol nebulization), and cluster(s) of patients which may get beneficial effects from this treatment.
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Affiliation(s)
- Antonio Simone Laganà
- Department of Obstetrics and Gynecology, "Filippo Del Ponte" Hospital, University of Insubria, Varese, Italy; The Experts Group on Inositol in Basic and Clinical Research (EGOI), Italy(1).
| | - Vittorio Unfer
- The Experts Group on Inositol in Basic and Clinical Research (EGOI), Italy(1); Systems Biology Group Lab, "La Sapienza" University, Rome, Italy
| | - Simone Garzon
- Department of Obstetrics and Gynecology, "Filippo Del Ponte" Hospital, University of Insubria, Varese, Italy
| | - Mariano Bizzarri
- The Experts Group on Inositol in Basic and Clinical Research (EGOI), Italy(1); Systems Biology Group Lab, "La Sapienza" University, Rome, Italy; Department of Experimental Medicine, "La Sapienza" University, Rome, Italy
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Szlasa W, Zendran I, Zalesińska A, Tarek M, Kulbacka J. Lipid composition of the cancer cell membrane. J Bioenerg Biomembr 2020; 52:321-342. [PMID: 32715369 PMCID: PMC7520422 DOI: 10.1007/s10863-020-09846-4] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022]
Abstract
Cancer cell possesses numerous adaptations to resist the immune system response and chemotherapy. One of the most significant properties of the neoplastic cells is the altered lipid metabolism, and consequently, the abnormal cell membrane composition. Like in the case of phosphatidylcholine, these changes result in the modulation of certain enzymes and accumulation of energetic material, which could be used for a higher proliferation rate. The changes are so prominent, that some lipids, such as phosphatidylserines, could even be considered as the cancer biomarkers. Additionally, some changes of biophysical properties of cell membranes lead to the higher resistance to chemotherapy, and finally to the disturbances in signalling pathways. Namely, the increased levels of certain lipids, like for instance phosphatidylserine, lead to the attenuation of the immune system response. Also, changes in lipid saturation prevent the cells from demanding conditions of the microenvironment. Particularly interesting is the significance of cell membrane cholesterol content in the modulation of metastasis. This review paper discusses the roles of each lipid type in cancer physiology. The review combined theoretical data with clinical studies to show novel therapeutic options concerning the modulation of cell membranes in oncology.
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Affiliation(s)
- Wojciech Szlasa
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | - Iga Zendran
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | | | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000, Nancy, France
| | - Julita Kulbacka
- Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wroclaw Medical University, Wrocław, Poland.
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Ho N, Yap WS, Xu J, Wu H, Koh JH, Goh WWB, George B, Chong SC, Taubert S, Thibault G. Stress sensor Ire1 deploys a divergent transcriptional program in response to lipid bilayer stress. J Cell Biol 2020; 219:e201909165. [PMID: 32349127 PMCID: PMC7337508 DOI: 10.1083/jcb.201909165] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/26/2020] [Accepted: 04/07/2020] [Indexed: 12/11/2022] Open
Abstract
Membrane integrity at the endoplasmic reticulum (ER) is tightly regulated, and its disturbance is implicated in metabolic diseases. Using an engineered sensor that activates the unfolded protein response (UPR) exclusively when normal ER membrane lipid composition is compromised, we identified pathways beyond lipid metabolism that are necessary to maintain ER integrity in yeast and in C. elegans. To systematically validate yeast mutants that disrupt ER membrane homeostasis, we identified a lipid bilayer stress (LBS) sensor in the UPR transducer protein Ire1, located at the interface of the amphipathic and transmembrane helices. Furthermore, transcriptome and chromatin immunoprecipitation analyses pinpoint the UPR as a broad-spectrum compensatory response wherein LBS and proteotoxic stress deploy divergent transcriptional UPR programs. Together, these findings reveal the UPR program as the sum of two independent stress responses, an insight that could be exploited for future therapeutic intervention.
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Affiliation(s)
- Nurulain Ho
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Wei Sheng Yap
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jiaming Xu
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Haoxi Wu
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jhee Hong Koh
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Wilson Wen Bin Goh
- Bio-Data Science and Education Research Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Bhawana George
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Shu Chen Chong
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Stefan Taubert
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Guillaume Thibault
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
- Institute of Molecular and Cell Biology, A*STAR, Singapore
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Rajakumar S, Vijayakumar R, Abhishek A, Selvam GS, Nachiappan V. Loss of ERAD bridging factor UBX2 modulates lipid metabolism and leads to ER stress-associated apoptosis during cadmium toxicity in Saccharomyces cerevisiae. Curr Genet 2020; 66:1003-1017. [DOI: 10.1007/s00294-020-01090-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/08/2020] [Accepted: 06/22/2020] [Indexed: 12/17/2022]
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Castells-Ballester J, Rinis N, Kotan I, Gal L, Bausewein D, Kats I, Zatorska E, Kramer G, Bukau B, Schuldiner M, Strahl S. Translational Regulation of Pmt1 and Pmt2 by Bfr1 Affects Unfolded Protein O-Mannosylation. Int J Mol Sci 2019; 20:ijms20246220. [PMID: 31835530 PMCID: PMC6940804 DOI: 10.3390/ijms20246220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 12/15/2022] Open
Abstract
O-mannosylation is implicated in protein quality control in Saccharomyces cerevisiae due to the attachment of mannose to serine and threonine residues of un- or misfolded proteins in the endoplasmic reticulum (ER). This process also designated as unfolded protein O-mannosylation (UPOM) that ends futile folding cycles and saves cellular resources is mainly mediated by protein O-mannosyltransferases Pmt1 and Pmt2. Here we describe a genetic screen for factors that influence O-mannosylation in yeast, using slow-folding green fluorescent protein (GFP) as a reporter. Our screening identifies the RNA binding protein brefeldin A resistance factor 1 (Bfr1) that has not been linked to O-mannosylation and ER protein quality control before. We find that Bfr1 affects O-mannosylation through changes in Pmt1 and Pmt2 protein abundance but has no effect on PMT1 and PMT2 transcript levels, mRNA localization to the ER membrane or protein stability. Ribosome profiling reveals that Bfr1 is a crucial factor for Pmt1 and Pmt2 translation thereby affecting unfolded protein O-mannosylation. Our results uncover a new level of regulation of protein quality control in the secretory pathway.
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Affiliation(s)
- Joan Castells-Ballester
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, D-69120 Heidelberg, Germany; (J.C.-B.); (N.R.); (D.B.); (E.Z.)
| | - Natalie Rinis
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, D-69120 Heidelberg, Germany; (J.C.-B.); (N.R.); (D.B.); (E.Z.)
| | - Ilgin Kotan
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), ZMBH-DKFZ Alliance, D-69120 Heidelberg, Germany; (I.K.); (I.K.); (G.K.); (B.B.)
| | - Lihi Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel; (L.G.); (M.S.)
| | - Daniela Bausewein
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, D-69120 Heidelberg, Germany; (J.C.-B.); (N.R.); (D.B.); (E.Z.)
- spm—Safety Projects & More GmbH, D-69493 Hirschberg a. d. Bergstraße, Germany
| | - Ilia Kats
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), ZMBH-DKFZ Alliance, D-69120 Heidelberg, Germany; (I.K.); (I.K.); (G.K.); (B.B.)
| | - Ewa Zatorska
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, D-69120 Heidelberg, Germany; (J.C.-B.); (N.R.); (D.B.); (E.Z.)
| | - Günter Kramer
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), ZMBH-DKFZ Alliance, D-69120 Heidelberg, Germany; (I.K.); (I.K.); (G.K.); (B.B.)
| | - Bernd Bukau
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), ZMBH-DKFZ Alliance, D-69120 Heidelberg, Germany; (I.K.); (I.K.); (G.K.); (B.B.)
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel; (L.G.); (M.S.)
| | - Sabine Strahl
- Centre for Organismal Studies (COS), Glycobiology, Heidelberg University, D-69120 Heidelberg, Germany; (J.C.-B.); (N.R.); (D.B.); (E.Z.)
- Correspondence: ; Tel.: +49-6221-54-6286
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Song MJ, Malhi H. The unfolded protein response and hepatic lipid metabolism in non alcoholic fatty liver disease. Pharmacol Ther 2019; 203:107401. [PMID: 31419516 PMCID: PMC6848795 DOI: 10.1016/j.pharmthera.2019.107401] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/08/2019] [Indexed: 12/19/2022]
Abstract
Nonalcoholic fatty liver disease is a major public health burden. Although many features of nonalcoholic fatty liver disease pathogenesis are known, the specific mechanisms and susceptibilities that determine an individual's risk of developing nonalcoholic steatohepatitis versus isolated steatosis are not well delineated. The predominant and defining histologic and imaging characteristic of nonalcoholic fatty liver disease is the accumulation of lipids. Dysregulation of lipid homeostasis in hepatocytes leads to transient generation or accumulation of toxic lipids that result in endoplasmic reticulum (ER) stress with inflammation, hepatocellular damage, and apoptosis. ER stress activates the unfolded protein response (UPR) which is classically viewed as an adaptive pathway to maintain protein folding homeostasis. Recent studies have uncovered the contribution of the UPR sensors in the regulation of hepatic steatosis and in the cellular response to lipotoxic stress. Interestingly, the UPR sensors can be directly activated by toxic lipids, independently of the accumulation of misfolded proteins, termed lipotoxic and proteotoxic stress, respectively. The dual function of the UPR sensors in protein and lipid homeostasis suggests that these two types of stress are interconnected likely due to the central role of the ER in protein folding and trafficking and lipid biosynthesis and trafficking, such that perturbations in either impact the function of the ER and activate the UPR sensors in an effort to restore homeostasis. The precise molecular similarities and differences between proteotoxic and lipotoxic ER stress are beginning to be understood. Herein, we provide an overview of the mechanisms involved in the activation and cross-talk between the UPR sensors, hepatic lipid metabolism, and lipotoxic stress, and discuss the possible therapeutic potential of targeting the UPR in nonalcoholic fatty liver disease.
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Affiliation(s)
- Myeong Jun Song
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, United States of America; Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Harmeet Malhi
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, United States of America.
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