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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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Kakiyama G, Minoiwa K, Bai-Kamara N, Hashiguchi T, Pandak WM, Rodriguez-Agudo D. StarD5 levels of expression correlate with onset and progression of steatosis and liver fibrosis. Am J Physiol Gastrointest Liver Physiol 2024; 326:G747-G761. [PMID: 38591148 PMCID: PMC11376981 DOI: 10.1152/ajpgi.00024.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/07/2024] [Accepted: 04/08/2024] [Indexed: 04/10/2024]
Abstract
Insufficient expression of steroidogenic acute regulatory-related lipid transfer protein 5 (StarD5) on liver cholesterol/lipid homeostasis is not clearly defined. The ablation of StarD5 was analyzed in mice on a normal or Western diet (WD) to determine its importance in hepatic lipid accumulation and fibrosis compared with wild-type (WT) mice. Rescue experiments in StarD5-/- mice and hepatocytes were performed. In addition to increased hepatic triglyceride (TG)-cholesterol levels, global StarD5-/- mice fed a normal diet displayed reduced plasma triglycerides and liver very low-density lipoprotein (VLDL) secretion as compared with WT counterparts. Insulin levels and homeostatic model assessment for insulin resistance (HOMA-IR) scoring were elevated, demonstrating developing insulin resistance (IR). WD-fed StarD5-/- mice upregulated WW domain containing transcription regulator 1 (TAZ or WWTR1) expression with accelerated liver fibrosis when compared with WD-fed WT mice. Suppression of oxysterol 7α-hydroxylase (CYP7B1) coupled with chronic accumulation of toxic oxysterol levels correlated with presentation of fibrosis. "Hepatocyte-selective" StarD5 overexpression in StarD5-/- mice restored expression, reduced hepatic triglycerides, and improved HOMA-IR. Observations in two additional mouse and one human metabolic dysfunction-associated steatotic liver disease (MASLD) model were supportive. The downregulation of StarD5 with hepatic lipid excess is a previously unappreciated physiological function appearing to promote lipid storage for future needs. Conversely, lingering downregulation of StarD5 with prolonged lipid-cholesterol excess accelerates fatty liver's transition to fibrosis; mediated via dysregulation in the oxysterol signaling pathway.NEW & NOTEWORTHY We have found that deletion of the cholesterol transport protein StarD5 in mice leads to an increase in insulin resistance and lipid accumulation due to the upregulation of lipid synthesis and decrease VLDL secretion from the liver. In addition, deletion of StarD5 increased fibrosis when mice were fed a Western diet. This represents a novel pathway of fibrosis development in the liver.
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Affiliation(s)
- Genta Kakiyama
- Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Research Services, Central Virginia Veterans Affairs Healthcare System, Richmond, Virginia, United States
| | - Kei Minoiwa
- Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Nanah Bai-Kamara
- Research Services, Central Virginia Veterans Affairs Healthcare System, Richmond, Virginia, United States
| | - Taishi Hashiguchi
- Research and Development Bureau, SMC Laboratories, Inc., Tokyo, Japan
| | - William M Pandak
- Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Research Services, Central Virginia Veterans Affairs Healthcare System, Richmond, Virginia, United States
| | - Daniel Rodriguez-Agudo
- Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States
- Research Services, Central Virginia Veterans Affairs Healthcare System, Richmond, Virginia, United States
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Heravi G, Liu Z, Herroon M, Wilson A, Fan YY, Jiang Y, Vakeesan N, Tao L, Peng Z, Zhang K, Li J, Chapkin RS, Podgorski I, Liu W. Targeting Fatty Acid Desaturase I Inhibits Renal Cancer Growth Via ATF3-mediated ER Stress Response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.23.586426. [PMID: 38586033 PMCID: PMC10996531 DOI: 10.1101/2024.03.23.586426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Monounsaturated fatty acids (MUFAs) play a pivotal role in maintaining endoplasmic reticulum (ER) homeostasis, an emerging hallmark of cancer. However, the role of polyunsaturated fatty acid (PUFAs) desaturation in persistent ER stress driven by oncogenic abnormalities remains elusive. Fatty Acid Desaturase 1 (FADS1) is a rate-limiting enzyme controlling the bioproduction of long-chain PUFAs. Our previous research has demonstrated the significant role of FADS1 in cancer survival, especially in kidney cancers. We explored the underlying mechanism in this study. We found that pharmacological inhibition or knockdown of the expression of FADS1 effectively inhibits renal cancer cell proliferation and induces cell cycle arrest. The stable knockdown of FADS1 also significantly inhibits tumor formation in vivo. Mechanistically, we show that while FADS1 inhibition induces ER stress, its expression is also augmented by ER-stress inducers. Notably, FADS1-inhibition sensitized cellular response to ER stress inducers, providing evidence of FADS1's role in modulating the ER stress response in cancer cells. We show that, while FADS1 inhibition-induced ER stress leads to activation of ATF3, ATF3-knockdown rescues the FADS1 inhibition-induced ER stress and cell growth suppression. In addition, FADS1 inhibition results in the impaired biosynthesis of nucleotides and decreases the level of UPD-N-Acetylglucosamine, a critical mediator of the unfolded protein response. Our findings suggest that PUFA desaturation is crucial for rescuing cancer cells from persistent ER stress, supporting FADS1 as a new therapeutic target.
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Affiliation(s)
- Gioia Heravi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Zhenjie Liu
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Mackenzie Herroon
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Alexis Wilson
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
- Department of Oncology, School of Medicine, Wayne State University, and Karmanos Cancer Institute, Detroit, MI 48201, USA
| | - Yang-Yi Fan
- Department of Nutrition, Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, 77843, USA
| | - Yang Jiang
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Nivisa Vakeesan
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Li Tao
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Zheyun Peng
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201, USA
- Department of Biochemistry, Microbiology, and Immunology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
- Department of Oncology, School of Medicine, Wayne State University, and Karmanos Cancer Institute, Detroit, MI 48201, USA
| | - Jing Li
- Department of Oncology, School of Medicine, Wayne State University, and Karmanos Cancer Institute, Detroit, MI 48201, USA
| | - Robert S. Chapkin
- Department of Nutrition, Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, 77843, USA
- CPRIT Regional Center of Excellence in Cancer Research, Texas A&M University, College Station, TX, 77843, USA
| | - Izabela Podgorski
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
- Department of Oncology, School of Medicine, Wayne State University, and Karmanos Cancer Institute, Detroit, MI 48201, USA
| | - Wanqing Liu
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
- Department of Oncology, School of Medicine, Wayne State University, and Karmanos Cancer Institute, Detroit, MI 48201, USA
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Wilkins AA, Schwarz B, Torres-Escobar A, Castore R, Landry L, Latimer B, Bohrnsen E, Bosio CM, Dragoi AM, Ivanov SS. The intracellular growth of the vacuolar pathogen Legionella pneumophila is dependent on the acyl chain composition of host membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.19.567753. [PMID: 38045297 PMCID: PMC10690232 DOI: 10.1101/2023.11.19.567753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Legionella pneumophila is an accidental human bacterial pathogen that infects and replicates within alveolar macrophages causing a severe atypical pneumonia known as Legionnaires' disease. As a prototypical vacuolar pathogen L. pneumophila establishes a unique endoplasmic reticulum (ER)-derived organelle within which bacterial replication takes place. Bacteria-derived proteins are deposited in the host cytosol and in the lumen of the pathogen-occupied vacuole via a type IVb (T4bSS) and a type II (T2SS) secretion system respectively. These secretion system effector proteins manipulate multiple host functions to facilitate intracellular survival of the bacteria. Subversion of host membrane glycerophospholipids (GPLs) by the internalized bacteria via distinct mechanisms feature prominently in trafficking and biogenesis of the Legionella -containing vacuole (LCV). Conventional GPLs composed of a glycerol backbone linked to a polar headgroup and esterified with two fatty acids constitute the bulk of membrane lipids in eukaryotic cells. The acyl chain composition of GPLs dictates phase separation of the lipid bilayer and therefore determines the physiochemical properties of biological membranes - such as membrane disorder, fluidity and permeability. In mammalian cells, fatty acids esterified in membrane GPLs are sourced endogenously from de novo synthesis or via internalization from the exogenous pool of lipids present in serum and other interstitial fluids. Here, we exploited the preferential utilization of exogenous fatty acids for GPL synthesis by macrophages to reprogram the acyl chain composition of host membranes and investigated its impact on LCV homeostasis and L. pneumophila intracellular replication. Using saturated fatty acids as well as cis - and trans - isomers of monounsaturated fatty acids we discovered that under conditions promoting lipid packing and membrane rigidification L. pneumophila intracellular replication was significantly reduced. Palmitoleic acid - a C16:1 monounsaturated fatty acid - that promotes membrane disorder when enriched in GPLs significantly increased bacterial replication within human and murine macrophages but not in axenic growth assays. Lipidome analysis of infected macrophages showed that treatment with exogenous palmitoleic acid resulted in membrane acyl chain reprogramming in a manner that promotes membrane disorder and live-cell imaging revealed that the consequences of increasing membrane disorder impinge on several LCV homeostasis parameters. Collectively, we provide experimental evidence that L. pneumophila replication within its intracellular niche is a function of the lipid bilayer disorder and hydrophobic thickness.
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Fatty Acyl Coenzyme A Synthetase Fat1p Regulates Vacuolar Structure and Stationary-Phase Lipophagy in Saccharomyces cerevisiae. Microbiol Spectr 2023; 11:e0462522. [PMID: 36598223 PMCID: PMC9927365 DOI: 10.1128/spectrum.04625-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
During yeast stationary phase, a single spherical vacuole (lysosome) is created by the fusion of several small ones. Moreover, the vacuolar membrane is reconstructed into two distinct microdomains. Little is known, however, about how cells maintain vacuolar shape or regulate their microdomains. Here, we show that Fat1p, a fatty acyl coenzyme A (acyl-CoA) synthetase and fatty acid transporter, and not the synthetases Faa1p and Faa4p, is essential for vacuolar shape preservation, the development of vacuolar microdomains, and cell survival in stationary phase of the yeast Saccharomyces cerevisiae. Furthermore, Fat1p negatively regulates general autophagy in both log- and stationary-phase cells. In contrast, Fat1p promotes lipophagy, as the absence of FAT1 limits the entry of lipid droplets into the vacuole and reduces the degradation of liquid droplet (LD) surface proteins. Notably, supplementing with unsaturated fatty acids or overexpressing the desaturase Ole1p can reverse all aberrant phenotypes caused by FAT1 deficiency. We propose that Fat1p regulates stationary phase vacuolar morphology, microdomain differentiation, general autophagy, and lipophagy by controlling the degree of fatty acid saturation in membrane lipids. IMPORTANCE The ability to sense environmental changes and adjust the levels of cellular metabolism is critical for cell viability. Autophagy is a recycling process that makes the most of already-existing energy resources, and the vacuole/lysosome is the ultimate autophagic processing site in cells. Lipophagy is an autophagic process to select degrading lipid droplets. In yeast cells in stationary phase, vacuoles fuse and remodel their membranes to create a single spherical vacuole with two distinct membrane microdomains, which are required for yeast lipophagy. In this study, we discovered that Fat1p was capable of rapidly responding to changes in nutritional status and preserving cell survival by regulating membrane lipid saturation to maintain proper vacuolar morphology and the level of lipophagy in the yeast S. cerevisiae. Our findings shed light on how cells maintain vacuolar structure and promote the differentiation of vacuole surface microdomains for stationary-phase lipophagy.
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Diosgenin Ameliorated Type II Diabetes-Associated Nonalcoholic Fatty Liver Disease through Inhibiting De Novo Lipogenesis and Improving Fatty Acid Oxidation and Mitochondrial Function in Rats. Nutrients 2022; 14:nu14234994. [PMID: 36501024 PMCID: PMC9738614 DOI: 10.3390/nu14234994] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/11/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
Diosgenin (DIO) is a dietary and phytochemical steroidal saponin representing multiple activities. The present study investigated the protective effect of DIO on type II diabetes-associated nonalcoholic fatty liver disease (D-NAFLD). The rat model was established by high-fat diet and streptozotocin injection and then administered DIO for 8 weeks. The results showed that DIO reduced insulin resistance index, improved dyslipidemia, and relieved pancreatic damage. DIO decreased hepatic injury markers, including aspartate aminotransferase (AST) and alanine aminotransferase (ALT). H&E staining showed that DIO relieved hepatic lipid deposition. Mechanistically, DIO inhibited hepatic de novo lipogenesis (DNL) and increased fatty acid β-oxidation (FAO) through regulation of the AMPK-ACC/SREBP1 pathway. Endoplasmic reticulum (ER) stress was inhibited by DIO through regulation of PERK and IRE1 arms, which may then inhibit DNL. DIO also decreased reactive oxygen species (ROS) and enhanced the antioxidant capacity via an increase in Superoxide dismutase (SOD), Catalase (CAT), and Glutathione peroxidase (GPx) activities. The mitochondria are the site for FAO, and ROS can damage mitochondrial function. DIO relieved mitochondrial fission and fusion disorder by inhibiting DRP1 and increasing MFN1/MFN2 expressions. Mitochondrial apoptosis was then inhibited by DIO. In conclusion, the present study suggests that DIO protects against D-NAFLD by inhibiting DNL and improving FAO and mitochondrial function.
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Lee J, Lee JK, Lee JJ, Park S, Jung S, Lee HJ, Ha JH. Partial Replacement of High-Fat Diet with Beef Tallow Attenuates Dyslipidemia and Endoplasmic Reticulum Stress in db/ db Mice. J Med Food 2022; 25:660-674. [PMID: 35617705 DOI: 10.1089/jmf.2022.k.0019] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
High-fat diet (HFD) consumption is closely associated with an increased risk of metabolic syndromes (MetS), such as obesity, type 2 diabetes, and cardiovascular diseases (CVDs). Therefore, the consumption of alternative and functional fatty acids to replace saturated fatty acids and/or trans-fatty acids with polyunsaturated fatty acids has become an important dietary strategy for the prevention of MetS. Consumption of omega-3 fatty acids (n-3) reduces various physiological complications, including CVDs, nonalcoholic fatty liver disease, and insulin resistance, related to inflammatory responses. In this study, we investigated the partial replacement effects of HFD with beef tallow (BT) on dyslipidemia and endoplasmic reticulum (ER) stress in male db/db mice. The animals were grouped to one of four dietary intervention groups (n = 16 per group): (1) normal diet, (2) HFD, (3) HFD partially replaced with regular beef tallow (HFD+BT1), or (4) HFD partially replaced with beef tallow containing a relatively reduced omega-6 fatty acid (n-6)/n-3 ratio (HFD+BT2) than HFD+BT1. After 6 weeks of dietary intervention, 1 mg/kg of phosphate-buffered saline or tunicamycin (TM) was injected intraperitoneally. HFD+BT2 significantly suppressed the serum total cholesterol and non-high-density lipoprotein cholesterol levels more than HFD and HFD+BT1, and triglyceride levels in the epididymal adipose tissue (EAT) were remarkably decreased. Mice that received HFD+BT2 had elevated protein expressions of phospho-AMP-activated protein kinase (p-AMPK). Moreover, HFD+BT2 effectively inhibited ER stress in the liver and EAT. Consistent with our hypothesis, HFD+BT2 remarkably alleviated dyslipidemia and TM-inducible ER stress, while activating p-AMPK.
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Affiliation(s)
- Jisu Lee
- Department of Food Science and Nutrition, Dankook University, Cheonan, Korea
| | - Jennifer K Lee
- Food Science and Human Nutrition Department, University of Florida, Gainesville, Florida, USA
| | - Jae-Joon Lee
- Department of Food and Nutrition, Chosun University, Gwangju, Korea
| | - Seohyun Park
- Department of Food Science and Nutrition, Dankook University, Cheonan, Korea
| | - Sunyoon Jung
- Department of Food Science and Nutrition, Dankook University, Cheonan, Korea
| | - Hyun-Joo Lee
- Department of Nutrition and Culinary Science, Hankyong National University, Ansung, Korea
| | - Jung-Heun Ha
- Department of Food Science and Nutrition, Dankook University, Cheonan, Korea.,Research Center for Industrialization of Natural Neutralization, Dankook University, Yongin, Korea
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Ampong I, John Ikwuobe O, Brown JEP, Bailey CJ, Gao D, Gutierrez-Merino J, Griffiths HR. Odd chain fatty acid metabolism in mice after a high fat diet. Int J Biochem Cell Biol 2021; 143:106135. [PMID: 34896612 PMCID: PMC8811477 DOI: 10.1016/j.biocel.2021.106135] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 11/27/2021] [Accepted: 12/07/2021] [Indexed: 11/18/2022]
Abstract
Epidemiological studies show that higher circulating levels of odd chain saturated fatty acids (FA: C15:0 and C17:0) are associated with lower risk of metabolic disease. These odd chain saturated fatty acids (OCSFA) are produced by α-oxidation in peroxisomes, de novo lipogenesis, from the diet and by gut microbiota. Although present at low concentrations, they are of interest as potential targets to reduce metabolic disease risk. To determine whether OCSFA are affected by obesogenic diets, we have investigated whether high dietary fat intake affects the frequency of OCSFA-producing gut microbiota, liver lipid metabolism genes and circulating OCSFA. FA concentrations were determined in liver and serum from pathogen-free SPF C57BL/6 J mice fed either standard chow or a high fat diet (HFD; 60% calories as fat) for four and twelve weeks. Post-mortem mouse livers were analysed histologically for fat deposition by gas chromatography-mass spectrometry for FA composition and by qPCR for the lipid metabolic genes fatty acid desaturase 2 (FADS2), stearoyl CoA desaturase 1 (SCD1), elongation of long-chain fatty acids family member 6 (ELOVL6) and 2-hydroxyacyl-CoA lyase 1 (HACL). Gut microbiota in faecal pellets from the ileum were analysed by 16S RNA sequencing. A significant depletion of serum and liver C15:0 (>50%; P < 0.05) and liver C17:0 (>35%; P < 0.05) was observed in HFD-fed SPF mice in parallel with hepatic fat accumulation after four weeks. In addition, liver gene expression (HACL1, ELOVL6, SCD1 and FADS2) was lower (>50%; P < 0.05) and the relative abundance of beneficial C3:0-producing gut bacteria such as Akkermansia, Lactobacillus, Bifidobacterium was lower after HFD in SPF mice. In summary, high dietary fat intake reduces serum and liver OCSFA, OCSFA-producing gut microbiota and is associated with impaired liver lipid metabolism. Further studies are required to identify whether there is any beneficial effect of OCSFA and C3:0-producing gut bacteria to counter metabolic disease.
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Affiliation(s)
- Isaac Ampong
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7XH, UK; School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - O John Ikwuobe
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7XH, UK; School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - James E P Brown
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7XH, UK; School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Clifford J Bailey
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7XH, UK; School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Dan Gao
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK; Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Jorge Gutierrez-Merino
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7XH, UK; School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Helen R Griffiths
- Faculty of Health and Medical Sciences, University of Surrey, GU2 7XH, UK; School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
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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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Human Cytomegalovirus Uses a Host Stress Response To Balance the Elongation of Saturated/Monounsaturated and Polyunsaturated Very-Long-Chain Fatty Acids. mBio 2021; 12:mBio.00167-21. [PMID: 33947752 PMCID: PMC8262922 DOI: 10.1128/mbio.00167-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Stress and virus infection regulate lipid metabolism. Human cytomegalovirus (HCMV) infection induces fatty acid (FA) elongation and increases the abundance of lipids with very-long-chain FA (VLCFA) tails. While reprogramming of metabolism can be stress related, the role of stress in HCMV reprogramming of lipid metabolism is poorly understood. In this study, we engineered cells to knock out protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) in the ER stress pathway and measured lipid changes using lipidomics to determine if PERK is needed for lipid changes associated with HCMV infection. In HCMV-infected cells, PERK promotes increases in the levels of phospholipids with saturated FA (SFA) and monounsaturated FA (MUFA) VLCFA tails. Further, PERK enhances FA elongase 7 (ELOVL7) protein levels, which elongates SFA and MUFA VLCFAs. Additionally, we found that increases in the elongation of polyunsaturated fatty acids (PUFAs) associated with HCMV infection were independent of PERK and that lipids with PUFA tails accumulated in HCMV-infected PERK knockout cells. Additionally, the protein levels of ELOVL5, which elongates PUFAs, are increased by HCMV infection through a PERK-independent mechanism. These observations show that PERK differentially regulates ELOVL7 and ELOVL5, creating a balance between the synthesis of lipids with SFA/MUFA tails and PUFA tails. Additionally, we found that PERK was necessary for virus replication and the infectivity of released viral progeny. Overall, our findings indicate that PERK—and, more broadly, ER stress—may be necessary for the membrane biogenesis needed to generate infectious HCMV virions.
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Fernandes-da-Silva A, Miranda CS, Santana-Oliveira DA, Oliveira-Cordeiro B, Rangel-Azevedo C, Silva-Veiga FM, Martins FF, Souza-Mello V. Endoplasmic reticulum stress as the basis of obesity and metabolic diseases: focus on adipose tissue, liver, and pancreas. Eur J Nutr 2021; 60:2949-2960. [PMID: 33742254 DOI: 10.1007/s00394-021-02542-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 03/11/2021] [Indexed: 12/11/2022]
Abstract
Obesity challenges lipid and carbohydrate metabolism. The resulting glucolipotoxicity causes endoplasmic reticulum (ER) dysfunction, provoking the accumulation of immature proteins, which triggers the unfolded protein reaction (UPR) as an attempt to reestablish ER homeostasis. When the three branches of UPR fail to correct the unfolded/misfolded proteins, ER stress happens. Excessive dietary saturated fatty acids or fructose exhibit the same impact on the ER stress, induced by excessive ectopic fat accumulation or rising blood glucose levels, and meta-inflammation. These metabolic abnormalities can alleviate through dietary interventions. Many pathways are disrupted in adipose tissue, liver, and pancreas during ER stress, compromising browning and thermogenesis, favoring hepatic lipogenesis, and impairing glucose-stimulated insulin secretion within pancreatic beta cells. As a result, ER stress takes part in obesity, hepatic steatosis, and diabetes pathogenesis, arising as a potential target to treat or even prevent metabolic diseases. The scientific community seeks strategies to alleviate ER stress by avoiding inflammation, apoptosis, lipogenesis suppression, and insulin sensitivity augmentation through pharmacological and non-pharmacological interventions. This comprehensive review aimed to describe the contribution of excessive dietary fat or sugar to ER stress and the impact of this adverse cellular environment on adipose tissue, liver, and pancreas function.
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Affiliation(s)
- Aline Fernandes-da-Silva
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Carolline Santos Miranda
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Daiana Araujo Santana-Oliveira
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Brenda Oliveira-Cordeiro
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Camilla Rangel-Azevedo
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Flávia Maria Silva-Veiga
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Fabiane Ferreira Martins
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Vanessa Souza-Mello
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil.
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12
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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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13
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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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14
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Sinha A, Israeli R, Cirigliano A, Gihaz S, Trabelcy B, Braus GH, Gerchman Y, Fishman A, Negri R, Rinaldi T, Pick E. The COP9 signalosome mediates the Spt23 regulated fatty acid desaturation and ergosterol biosynthesis. FASEB J 2020; 34:4870-4889. [PMID: 32077151 DOI: 10.1096/fj.201902487r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/02/2020] [Accepted: 01/14/2020] [Indexed: 02/06/2023]
Abstract
The COP9 signalosome (CSN) is a conserved eukaryotic complex, essential for vitality in all multicellular organisms and critical for the turnover of key cellular proteins through catalytic and non-catalytic activities. Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of the CSN complex, since it includes a conserved enzymatic core but lacks non-catalytic activities, probably explaining its non-essentiality for life. A previous transcriptomic analysis of an S. cerevisiae strain deleted in the CSN5/RRI1 gene, encoding to the CSN catalytic subunit, revealed a downregulation of genes involved in lipid metabolism. We now show that the S. cerevisiae CSN holocomplex is essential for cellular lipid homeostasis. Defects in CSN assembly or activity lead to decreased quantities of ergosterol and unsaturated fatty acids (UFA); vacuole defects; diminished lipid droplets (LDs) size; and to accumulation of endoplasmic reticulum (ER) stress. The molecular mechanism behind these findings depends on CSN involvement in upregulating mRNA expression of SPT23. Spt23 is a novel activator of lipid desaturation and ergosterol biosynthesis. Our data reveal for the first time a functional link between the CSN holocomplex and Spt23. Moreover, CSN-dependent upregulation of SPT23 transcription is necessary for the fine-tuning of lipid homeostasis and for cellular health.
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Affiliation(s)
- Abhishek Sinha
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Ran Israeli
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Angela Cirigliano
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Shalev Gihaz
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Beny Trabelcy
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Yoram Gerchman
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Ayelet Fishman
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rodolfo Negri
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Teresa Rinaldi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Elah Pick
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
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15
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Palmitic acid damages gut epithelium integrity and initiates inflammatory cytokine production. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158530. [DOI: 10.1016/j.bbalip.2019.158530] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 07/16/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023]
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16
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Medkour Y, Mohammad K, Arlia-Ciommo A, Svistkova V, Dakik P, Mitrofanova D, Rodriguez MEL, Junio JAB, Taifour T, Escudero P, Goltsios FF, Soodbakhsh S, Maalaoui H, Simard É, Titorenko VI. Mechanisms by which PE21, an extract from the white willow Salix alba, delays chronological aging in budding yeast. Oncotarget 2019; 10:5780-5816. [PMID: 31645900 PMCID: PMC6791382 DOI: 10.18632/oncotarget.27209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 08/27/2019] [Indexed: 01/05/2023] Open
Abstract
We have recently found that PE21, an extract from the white willow Salix alba, slows chronological aging and prolongs longevity of the yeast Saccharomyces cerevisiae more efficiently than any of the previously known pharmacological interventions. Here, we investigated mechanisms through which PE21 delays yeast chronological aging and extends yeast longevity. We show that PE21 causes a remodeling of lipid metabolism in chronologically aging yeast, thereby instigating changes in the concentrations of several lipid classes. We demonstrate that such changes in the cellular lipidome initiate three mechanisms of aging delay and longevity extension. The first mechanism through which PE21 slows aging and prolongs longevity consists in its ability to decrease the intracellular concentration of free fatty acids. This postpones an age-related onset of liponecrotic cell death promoted by excessive concentrations of free fatty acids. The second mechanism of aging delay and longevity extension by PE21 consists in its ability to decrease the concentrations of triacylglycerols and to increase the concentrations of glycerophospholipids within the endoplasmic reticulum membrane. This activates the unfolded protein response system in the endoplasmic reticulum, which then decelerates an age-related decline in protein and lipid homeostasis and slows down an aging-associated deterioration of cell resistance to stress. The third mechanisms underlying aging delay and longevity extension by PE21 consists in its ability to change lipid concentrations in the mitochondrial membranes. This alters certain catabolic and anabolic processes in mitochondria, thus amending the pattern of aging-associated changes in several key aspects of mitochondrial functionality.
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Affiliation(s)
- Younes Medkour
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Karamat Mohammad
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | | | - Veronika Svistkova
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Pamela Dakik
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Darya Mitrofanova
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | | | | | - Tarek Taifour
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Paola Escudero
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Fani-Fay Goltsios
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Sahar Soodbakhsh
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Hana Maalaoui
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Éric Simard
- Idunn Technologies Inc., Rosemere, Quebec J7A 4A5, Canada
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17
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de Mendoza D, Pilon M. Control of membrane lipid homeostasis by lipid-bilayer associated sensors: A mechanism conserved from bacteria to humans. Prog Lipid Res 2019; 76:100996. [DOI: 10.1016/j.plipres.2019.100996] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022]
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18
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Phosphatidic acid in membrane rearrangements. FEBS Lett 2019; 593:2428-2451. [PMID: 31365767 DOI: 10.1002/1873-3468.13563] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/16/2022]
Abstract
Phosphatidic acid (PA) is the simplest cellular glycerophospholipid characterized by unique biophysical properties: a small headgroup; negative charge; and a phosphomonoester group. Upon interaction with lysine or arginine, PA charge increases from -1 to -2 and this change stabilizes protein-lipid interactions. The biochemical properties of PA also allow interactions with lipids in several subcellular compartments. Based on this feature, PA is involved in the regulation and amplification of many cellular signalling pathways and functions, as well as in membrane rearrangements. Thereby, PA can influence membrane fusion and fission through four main mechanisms: it is a substrate for enzymes producing lipids (lysophosphatidic acid and diacylglycerol) that are involved in fission or fusion; it contributes to membrane rearrangements by generating negative membrane curvature; it interacts with proteins required for membrane fusion and fission; and it activates enzymes whose products are involved in membrane rearrangements. Here, we discuss the biophysical properties of PA in the context of the above four roles of PA in membrane fusion and fission.
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Affiliation(s)
- Mikhail A Zhukovsky
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Angela Filograna
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Daniela Corda
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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19
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Mo FF, Lv BH, An T, Miao JN, Liu JX, Zhang J, Zhang ZY, Ma MH, Yang XY, Zhao DD, Zhang DW, Gao SH, Jiang GJ. Protective mechanism of punicalagin against endoplasmic reticulum stress in the liver of mice with type 2 diabetes mellitus. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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20
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Seessle J, Liebisch G, Schmitz G, Stremmel W, Chamulitrat W. Compositional Changes Among Triglycerides and Phospholipids During FATP4 Sensitization with Palmitate Lead to ER Stress in Cultured Cells. EUR J LIPID SCI TECH 2019. [DOI: 10.1002/ejlt.201800394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jessica Seessle
- Department of Internal Medicine IVGastroenterology and Infectious DiseaseIm Neuenheimer Feld 41069120HeidelbergGermany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory MedicineUniversity of RegensburgFranz‐Josef‐Strauss‐Allee 1193053RegensburgGermany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory MedicineUniversity of RegensburgFranz‐Josef‐Strauss‐Allee 1193053RegensburgGermany
| | - Wolfgang Stremmel
- Department of Internal Medicine IVGastroenterology and Infectious DiseaseIm Neuenheimer Feld 41069120HeidelbergGermany
| | - Walee Chamulitrat
- Department of Internal Medicine IVGastroenterology and Infectious DiseaseIm Neuenheimer Feld 41069120HeidelbergGermany
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21
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Covino R, Hummer G, Ernst R. Integrated Functions of Membrane Property Sensors and a Hidden Side of the Unfolded Protein Response. Mol Cell 2019; 71:458-467. [PMID: 30075144 DOI: 10.1016/j.molcel.2018.07.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/09/2018] [Accepted: 07/17/2018] [Indexed: 12/26/2022]
Abstract
Eukaryotic cells face the challenge of maintaining the complex composition of several coexisting organelles. The molecular mechanisms underlying the homeostasis of subcellular membranes and their adaptation during stress are only now starting to emerge. Here, we discuss three membrane property sensors of the endoplasmic reticulum (ER), namely OPI1, MGA2, and IRE1, each controlling a large cellular program impacting the lipid metabolic network. OPI1 coordinates the production of membrane and storage lipids, MGA2 regulates the production of unsaturated fatty acids required for membrane biogenesis, and IRE1 controls the unfolded protein response (UPR) to adjust ER size, protein folding, and the secretory capacity of the cell. Although these proteins use remarkably distinct sensing mechanisms, they are functionally connected via the ER membrane and cooperate to maintain membrane homeostasis. As a rationalization of the recently described mechanism of UPR activation by lipid bilayer stress, we propose that IRE1 can sense the protein-to-lipid ratio in the ER membrane to ensure a balanced production of membrane proteins and lipids.
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Affiliation(s)
- Roberto Covino
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany; Institute of Biophysics, Goethe University, 60438 Frankfurt am Main, Germany
| | - Robert Ernst
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Kirrberger Str. 100, Gebäude 61.4, 66421 Homburg, Germany.
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22
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Pichler H, Emmerstorfer-Augustin A. Modification of membrane lipid compositions in single-celled organisms – From basics to applications. Methods 2018; 147:50-65. [DOI: 10.1016/j.ymeth.2018.06.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/18/2018] [Accepted: 06/16/2018] [Indexed: 12/12/2022] Open
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23
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Yi Z, Fangfang M, Dongwei Z, Sihua G, Dandan Z, Na Y, Qianqian M, Jiacheng Z, Yue M. Jiangtang Xiaoke granule attenuates glucose metabolism disorder via regulating endoplasmic reticulum stress in the liver of type 2 diabetes mellitus mice. J TRADIT CHIN MED 2018. [DOI: 10.1016/s0254-6272(18)30889-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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24
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Kadri L, Ferru-Clément R, Bacle A, Payet LA, Cantereau A, Hélye R, Becq F, Jayle C, Vandebrouck C, Ferreira T. Modulation of cellular membrane properties as a potential therapeutic strategy to counter lipointoxication in obstructive pulmonary diseases. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3069-3084. [PMID: 29960042 DOI: 10.1016/j.bbadis.2018.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/04/2018] [Accepted: 06/25/2018] [Indexed: 02/08/2023]
Abstract
Maintaining the equilibrium between saturated and unsaturated fatty acids within membrane phospholipids (PLs) is crucial to sustain the optimal membrane biophysical properties, compatible with selective organelle-based processes. Lipointoxication is a pathological condition under which saturated PLs tend to accumulate within the cell at the expense of unsaturated species, with major impacts on organelle function. Here, we show that human bronchial epithelial cells extracted from lungs of patients with Obstructive Pulmonary Diseases (OPDs), i. e. Cystic Fibrosis (CF) individuals and Smokers, display a characteristic lipointoxication signature, with excessive amounts of saturated PLs. Reconstitution of this signature in cellulo and in silico revealed that such an imbalance results in altered membrane properties and in a dramatic disorganization of the intracellular network of bronchial epithelial cells, in a process which can account for several OPD traits. Such features include Endoplasmic Reticulum-stress, constitutive IL8 secretion, bronchoconstriction and, ultimately, epithelial cell death by apoptosis. We also demonstrate that a recently-identified lipid-like molecule, which has been shown to behave as a "membrane-reshaper", counters all the lipointoxication hallmarks tested. Altogether, these insights highlight the modulation of membrane properties as a potential new strategy to heal and prevent highly detrimental symptoms associated with OPDs.
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Affiliation(s)
- Linette Kadri
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Romain Ferru-Clément
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Amélie Bacle
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Laurie-Anne Payet
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Anne Cantereau
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Reynald Hélye
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Frédéric Becq
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Christophe Jayle
- Service de Chirurgie Cardiothoracique, CHU Poitiers, Poitiers, France
| | - Clarisse Vandebrouck
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM)", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France
| | - Thierry Ferreira
- Laboratoire Coopératif "Lipotoxicity and Channelopathies - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, Poitiers, France.
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25
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Hofbauer HF, Gecht M, Fischer SC, Seybert A, Frangakis AS, Stelzer EHK, Covino R, Hummer G, Ernst R. The molecular recognition of phosphatidic acid by an amphipathic helix in Opi1. J Cell Biol 2018; 217:3109-3126. [PMID: 29941475 PMCID: PMC6122994 DOI: 10.1083/jcb.201802027] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/28/2018] [Accepted: 06/18/2018] [Indexed: 01/09/2023] Open
Abstract
Phosphatidic acid (PA) lipids have a dual role as building blocks for membrane biogenesis and as active signaling molecules. This study establishes the molecular details of selective PA recognition by the transcriptional regulator Opi1 from baker’s yeast. A key event in cellular physiology is the decision between membrane biogenesis and fat storage. Phosphatidic acid (PA) is an important intermediate at the branch point of these pathways and is continuously monitored by the transcriptional repressor Opi1 to orchestrate lipid metabolism. In this study, we report on the mechanism of membrane recognition by Opi1 and identify an amphipathic helix (AH) for selective binding of PA over phosphatidylserine (PS). The insertion of the AH into the membrane core renders Opi1 sensitive to the lipid acyl chain composition and provides a means to adjust membrane biogenesis. By rational design of the AH, we tune the membrane-binding properties of Opi1 and control its responsiveness in vivo. Using extensive molecular dynamics simulations, we identify two PA-selective three-finger grips that tightly bind the PA phosphate headgroup while interacting less intimately with PS. This work establishes lipid headgroup selectivity as a new feature in the family of AH-containing membrane property sensors.
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Affiliation(s)
- Harald F Hofbauer
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany .,Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany.,Institute of Medical Biochemistry and Molecular Biology, School of Medicine, University of Saarland, Homburg, Germany
| | - Michael Gecht
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany.,Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt, Germany.,Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Sabine C Fischer
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany.,Physical Biology, Interdisciplinary Center for Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Anja Seybert
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Achilleas S Frangakis
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Ernst H K Stelzer
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany.,Physical Biology, Interdisciplinary Center for Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Roberto Covino
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt, Germany.,Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany
| | - Robert Ernst
- Institute of Medical Biochemistry and Molecular Biology, School of Medicine, University of Saarland, Homburg, Germany
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26
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Ernst R, Ballweg S, Levental I. Cellular mechanisms of physicochemical membrane homeostasis. Curr Opin Cell Biol 2018; 53:44-51. [PMID: 29787971 DOI: 10.1016/j.ceb.2018.04.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/19/2018] [Accepted: 04/29/2018] [Indexed: 12/11/2022]
Abstract
Biological membranes are vital, active contributors to cell function. In addition to specific interactions of individual lipid molecules and lateral organization produced by membrane domains, the bulk physicochemical properties of biological membranes broadly regulate protein structure and function. Therefore, these properties must be homeostatically maintained within a narrow range that is compatible with cellular physiology. Although such adaptiveness has been known for decades, recent observations have dramatically expanded its scope by showing the breadth of membrane properties that must be maintained, and revealing the remarkable diversity of biological membranes, both within and between cell types. Cells have developed a broad palette of sense-and-respond machineries to mediate physicochemical membrane homeostasis, and the molecular mechanisms of these are being discovered through combinations of cell biology, biophysical approaches, and computational modeling.
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Affiliation(s)
- Robert Ernst
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany.
| | - Stephanie Ballweg
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Science Center, Houston, TX, USA.
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27
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Johnston LW, Harris SB, Retnakaran R, Giacca A, Liu Z, Bazinet RP, Hanley AJ. Association of NEFA composition with insulin sensitivity and beta cell function in the Prospective Metabolism and Islet Cell Evaluation (PROMISE) cohort. Diabetologia 2018; 61:821-830. [PMID: 29275428 DOI: 10.1007/s00125-017-4534-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/14/2017] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Our aim was to determine the longitudinal associations of individual NEFA with the pathogenesis of diabetes, specifically with differences in insulin sensitivity and beta cell function over 6 years in a cohort of individuals who are at risk for diabetes. METHODS In the Prospective Metabolism and Islet Cell Evaluation (PROMISE) longitudinal cohort, 477 participants had serum NEFA measured at the baseline visit and completed an OGTT at three time points over 6 years. Outcome variables were calculated using the OGTT values. At each visit, insulin sensitivity was assessed using the HOMA2 of insulin sensitivity (HOMA2-%S) and the Matsuda index, while beta cell function was assessed using the insulinogenic index over HOMA-IR (IGI/IR) and the insulin secretion-sensitivity index-2 (ISSI-2). Generalised estimating equations were used, adjusting for time, waist, sex, ethnicity, baseline age, alanine aminotransferase (ALT) and physical activity. NEFA were analysed as both concentrations (nmol/ml) and proportions (mol%) of the total fraction. RESULTS Participants' (73% female, 70% with European ancestry) insulin sensitivity and beta cell function declined by 14-21% over 6 years of follow-up. In unadjusted models, several NEFA (e.g. 18:1 n-7, 22:4 n-6) were associated with lower insulin sensitivity, however, nearly all of these associations were attenuated in fully adjusted models. In adjusted models, total NEFA, 16:0, 18:1 n-9 and 18:2 n-6 (as concentrations) were associated with 3.7-8.0% lower IGI/IR and ISSI-2, while only 20:5 n-3 (as mol%) was associated with 7.7% higher HOMA2-%S. CONCLUSIONS/INTERPRETATION Total NEFA concentration was a strong predictor of lower beta cell function over 6 years. Our results suggest that the association with beta cell function is due to the absolute size of the serum NEFA fraction, rather than the specific fatty acid composition.
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Affiliation(s)
- Luke W Johnston
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, FitzGerald Building, 150 College Street, Toronto, ON, M5S 3E2, Canada
| | - Stewart B Harris
- Centre for Studies in Family Medicine, University of Western Ontario, London, ON, Canada
| | - Ravi Retnakaran
- Division of Endocrinology, University of Toronto, Toronto, ON, Canada
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Adria Giacca
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Zhen Liu
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, FitzGerald Building, 150 College Street, Toronto, ON, M5S 3E2, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, FitzGerald Building, 150 College Street, Toronto, ON, M5S 3E2, Canada
| | - Anthony J Hanley
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, FitzGerald Building, 150 College Street, Toronto, ON, M5S 3E2, Canada.
- Division of Endocrinology, University of Toronto, Toronto, ON, Canada.
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
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Del Vecchio K, Stahelin RV. Investigation of the phosphatidylserine binding properties of the lipid biosensor, Lactadherin C2 (LactC2), in different membrane environments. J Bioenerg Biomembr 2018; 50:1-10. [PMID: 29426977 DOI: 10.1007/s10863-018-9745-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 01/31/2018] [Indexed: 01/07/2023]
Abstract
Lipid biosensors are robust tools used in both in vitro and in vivo applications of lipid imaging and lipid detection. Lactadherin C2 (LactC2) was described in 2000 as being a potent and specific sensor for phosphatidylserine (PS) (Andersen et al. Biochemistry 39:6200-6206, 2000). PS is an anionic phospholipid enriched in the inner leaflet of the plasma membrane and has paramount roles in apoptosis, cells signaling, and autophagy. The myriad roles PS plays in membrane dynamics make monitoring PS levels and function an important endeavor. LactC2 has functioned as a tantamount PS biosensor namely in the field of cellular imaging. While PS specificity and high affinity of LactC2 for PS containing membranes has been well established, much less is known regarding LactC2 selectivity for subcellular pools of PS or PS within different membrane environments (e.g., in the presence of cholesterol). Thus, there has been a lack of studies that have compared LactC2 PS sensitivity based upon the acyl chain length and saturation or the presence of other host lipids such as cholesterol. Here, we use surface plasmon resonance as a label-free method to quantitatively assess the apparent binding affinity of LactC2 for membranes containing PS with different acyl chains, different fluidity, as well as representative lipid vesicle mimetics of cellular membranes. Results demonstrate that LactC2 is an unbiased sensor for PS, and can sensitively interact with membranes containing PS with different acyl chain saturation and interact with PS species in a cholesterol-independent manner.
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Affiliation(s)
- Kathryn Del Vecchio
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Robert V Stahelin
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA. .,Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47907, USA.
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29
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Ho N, Xu C, Thibault G. From the unfolded protein response to metabolic diseases - lipids under the spotlight. J Cell Sci 2018; 131:131/3/jcs199307. [PMID: 29439157 DOI: 10.1242/jcs.199307] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The unfolded protein response (UPR) is classically viewed as a stress response pathway to maintain protein homeostasis at the endoplasmic reticulum (ER). However, it has recently emerged that the UPR can be directly activated by lipid perturbation, independently of misfolded proteins. Comprising primarily phospholipids, sphingolipids and sterols, individual membranes can contain hundreds of distinct lipids. Even with such complexity, lipid distribution in a cell is tightly regulated by mechanisms that remain incompletely understood. It is therefore unsurprising that lipid dysregulation can be a key factor in disease development. Recent advances in analysis of lipids and their regulators have revealed remarkable mechanisms and connections to other cellular pathways including the UPR. In this Review, we summarize the current understanding in UPR transducers functioning as lipid sensors and the interplay between lipid metabolism and ER homeostasis in the context of metabolic diseases. We attempt to provide a framework consisting of a few key principles to integrate the different lines of evidence and explain this rather complicated mechanism.
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Affiliation(s)
- Nurulain Ho
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551
| | - Chengchao Xu
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142-1479, USA
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551
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30
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Ma MKF, Lau EYT, Leung DHW, Lo J, Ho NPY, Cheng LKW, Ma S, Lin CH, Copland JA, Ding J, Lo RCL, Ng IOL, Lee TKW. Stearoyl-CoA desaturase regulates sorafenib resistance via modulation of ER stress-induced differentiation. J Hepatol 2017. [PMID: 28647567 DOI: 10.1016/j.jhep.2017.06.015] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS We investigated the functional role and clinical significance of stearoyl-CoA desaturase-1 (SCD1) mediated endoplasmic reticulum (ER) stress in regulating liver tumor-initiating cells (T-ICs) and sorafenib resistance, with the aim of developing a novel therapeutic strategy against hepatocellular carcinomas (HCCs). METHODS We evaluated the clinic-pathological relevance of SCD1 and its correlation with sorafenib resistance in large cohorts of HCC clinical samples by qPCR and immunohistochemical analyses. Lentiviral-based overexpression and knockdown approaches were performed to characterize the functional roles of SCD1 in regulating liver T-ICs and sorafenib resistance. Molecular pathways mediating the phenotypic alterations were identified through RNA sequencing analysis and functional rescue experiments. The combinatorial effect of SCD1 inhibition and sorafenib was tested using a patient-derived tumor xenograft (PDTX) model. RESULTS SCD1 overexpression was found in HCC, which was associated with shorter disease-free survival (p = 0.008, log rank test). SCD1 was found to regulate the populations of liver T-ICs; while its suppression by a SCD1 inhibitor suppressed liver T-ICs and sorafenib resistance. Interestingly, SCD1 was markedly upregulated in our established sorafenib-resistant PDTX model, and its overexpression predicts the clinical response of HCC patients to sorafenib treatment. Suppression of SCD1 forces liver T-ICs to differentiate via ER stress-induced unfolded protein response, resulting in an enhanced sensitivity to sorafenib. The PDTX#1 model, combined with sorafenib treatment and a novel SCD1 inhibitor (SSI-4), showed a maximal growth suppressive effect. CONCLUSIONS SCD1-mediated ER stress regulates liver T-ICs and sorafenib sensitivity. Targeting SCD1 alone or in combination with sorafenib might be a novel personalized medicine against HCC. Lay summary: In this study, SCD1 was found to play a critical role in regulating liver tumor-initiating cells and sorafenib resistance through the regulation of ER stress-mediated differentiation. Targeting SCD1 in combination with sorafenib may be a novel therapeutic strategy against liver cancer.
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Affiliation(s)
- Mark Kin Fai Ma
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Eunice Yuen Ting Lau
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong; Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong
| | - Doris Hoi Wing Leung
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Jessica Lo
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Nicole Pui Yu Ho
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Lily Kwan Wai Cheng
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Stephanie Ma
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Chi Ho Lin
- Centre for Genomic Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - John A Copland
- Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, United States
| | - Jin Ding
- Eastern Hepatobiliary Surgery Hospital, The International Cooperation Laboratory on Signal Transduction, China
| | - Regina Cheuk Lam Lo
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Irene Oi Lin Ng
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
| | - Terence Kin Wah Lee
- State Key Laboratory for Liver Research, The University of Hong Kong, Hong Kong; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong; State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hong Kong.
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Cohen N, Breker M, Bakunts A, Pesek K, Chas A, Argemí J, Orsi A, Gal L, Chuartzman S, Wigelman Y, Jonas F, Walter P, Ernst R, Aragón T, van Anken E, Schuldiner M. Iron affects Ire1 clustering propensity and the amplitude of endoplasmic reticulum stress signaling. J Cell Sci 2017; 130:3222-3233. [PMID: 28794014 PMCID: PMC5665437 DOI: 10.1242/jcs.201715] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 08/02/2017] [Indexed: 01/10/2023] Open
Abstract
The unfolded protein response (UPR) allows cells to adjust secretory pathway capacity according to need. Ire1, the endoplasmic reticulum (ER) stress sensor and central activator of the UPR is conserved from the budding yeast Saccharomyces cerevisiae to humans. Under ER stress conditions, Ire1 clusters into foci that enable optimal UPR activation. To discover factors that affect Ire1 clustering, we performed a high-content screen using a whole-genome yeast mutant library expressing Ire1–mCherry. We imaged the strains following UPR induction and found 154 strains that displayed alterations in Ire1 clustering. The hits were enriched for iron and heme effectors and binding proteins. By performing pharmacological depletion and repletion, we confirmed that iron (Fe3+) affects UPR activation in both yeast and human cells. We suggest that Ire1 clustering propensity depends on membrane composition, which is governed by heme-dependent biosynthesis of sterols. Our findings highlight the diverse cellular functions that feed into the UPR and emphasize the cross-talk between organelles required to concertedly maintain homeostasis. Highlighted Article: To respond to folding stress in the ER, cells activate the conserved sensor Ire1. We show that iron is required for optimal Ire1 activation and suggest this is because iron is required for ergosterol biosynthesis.
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Affiliation(s)
- Nir Cohen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Michal Breker
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.,The Rockefeller University, New York, NY 10065, USA
| | - Anush Bakunts
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Ospedale San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | - Kristina Pesek
- Institute of Biochemistry and Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue Str. 15, 60438 Frankfurt, Germany
| | - Ainara Chas
- Center for Applied Medical Research, Department of Gene Therapy and Regulation of Gene Expression. University of Navarra, 55 Pio XII St. 31008 Pamplona, Spain
| | - Josepmaria Argemí
- Center for Applied Medical Research, Department of Gene Therapy and Regulation of Gene Expression. University of Navarra, 55 Pio XII St. 31008 Pamplona, Spain
| | - Andrea Orsi
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Ospedale San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | - Lihi Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Silvia Chuartzman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yoav Wigelman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Felix Jonas
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Peter Walter
- Department of Biochemistry & Biophysics, University of California San Francisco and Howard Hughes Medical Institute, San Francisco, CA 94143, USA
| | - Robert Ernst
- Center for Molecular Signaling, Institute of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Tomás Aragón
- Center for Applied Medical Research, Department of Gene Therapy and Regulation of Gene Expression. University of Navarra, 55 Pio XII St. 31008 Pamplona, Spain
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Ospedale San Raffaele, Via Olgettina 58, 20132, Milan, Italy
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
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32
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Ethanolamine and Phosphatidylethanolamine: Partners in Health and Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:4829180. [PMID: 28785375 PMCID: PMC5529665 DOI: 10.1155/2017/4829180] [Citation(s) in RCA: 204] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022]
Abstract
Phosphatidylethanolamine (PE) is the second most abundant phospholipid in mammalian cells. PE comprises about 15–25% of the total lipid in mammalian cells; it is enriched in the inner leaflet of membranes, and it is especially abundant in the inner mitochondrial membrane. PE has quite remarkable activities: it is a lipid chaperone that assists in the folding of certain membrane proteins, it is required for the activity of several of the respiratory complexes, and it plays a key role in the initiation of autophagy. In this review, we focus on PE's roles in lipid-induced stress in the endoplasmic reticulum (ER), Parkinson's disease (PD), ferroptosis, and cancer.
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33
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Jackson CL, Walch L, Verbavatz JM. Lipids and Their Trafficking: An Integral Part of Cellular Organization. Dev Cell 2017; 39:139-153. [PMID: 27780039 DOI: 10.1016/j.devcel.2016.09.030] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An evolutionarily conserved feature of cellular organelles is the distinct phospholipid composition of their bounding membranes, which is essential to their identity and function. Within eukaryotic cells, two major lipid territories can be discerned, one centered on the endoplasmic reticulum and characterized by membranes with lipid packing defects, the other comprising plasma-membrane-derived organelles and characterized by membrane charge. We discuss how this cellular lipid organization is maintained, how lipid flux is regulated, and how perturbations in cellular lipid homeostasis can lead to disease.
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Affiliation(s)
- Catherine L Jackson
- Institut Jacques Monod, CNRS, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France.
| | - Laurence Walch
- Institut Jacques Monod, CNRS, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
| | - Jean-Marc Verbavatz
- Institut Jacques Monod, CNRS, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
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34
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Kono N, Amin-Wetzel N, Ron D. Generic membrane-spanning features endow IRE1α with responsiveness to membrane aberrancy. Mol Biol Cell 2017; 28:2318-2332. [PMID: 28615323 PMCID: PMC5555659 DOI: 10.1091/mbc.e17-03-0144] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/07/2017] [Accepted: 06/09/2017] [Indexed: 12/16/2022] Open
Abstract
Previous studies indicated that IRE1α responds to membrane aberrancy via its transmembrane domain (TMD); however, little is known about the TMD features involved. Use of CRISPR/Cas9-mediated gene editing shows that generic membrane-spanning features of the TMD are sufficient for IRE1α’s responsiveness to membrane aberrancy. Altered cellular lipid composition activates the endoplasmic reticulum unfolded protein response (UPR), and UPR signaling effects important changes in lipid metabolism. Secondary effects on protein folding homeostasis likely contribute to UPR activation, but deletion of the unfolded protein stress-sensing luminal domain of the UPR transducers PERK and IRE1α does not abolish their responsiveness to lipid perturbation. This finding suggests that PERK and IRE1α also directly recognize the membrane aberrancy wrought by lipid perturbation. However, beyond the need for a transmembrane domain (TMD), little is known about the features involved. Regulation of the UPR transducers entails changes in their oligomeric state and is easily corrupted by overexpression. We used CRISPR/Cas9-mediated gene editing of the Ern1 locus to study the role of the TMD in the ability of the endogenous IRE1α protein to recognize membrane aberrancy in mammalian cells. Conducted in the background of a point mutation that isolated the response to membrane aberrancy induced by palmitate from unfolded protein stress, our analysis shows that generic membrane-spanning features of the TMD are sufficient for IRE1α’s responsiveness to membrane aberrancy. Our data suggest that IRE1α’s conserved TMD may have been selected for features imparting a relatively muted response to acyl-chain saturation.
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Affiliation(s)
- Nozomu Kono
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Niko Amin-Wetzel
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - David Ron
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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35
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Oteng AB, Bhattacharya A, Brodesser S, Qi L, Tan NS, Kersten S. Feeding Angptl4-/- mice trans fat promotes foam cell formation in mesenteric lymph nodes without leading to ascites. J Lipid Res 2017; 58:1100-1113. [PMID: 28412693 DOI: 10.1194/jlr.m074278] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/10/2017] [Indexed: 12/28/2022] Open
Abstract
Angiopoietin-like 4 (ANGPTL4) regulates plasma triglyceride levels by inhibiting LPL. Inactivation of ANGPTL4 decreases plasma triglycerides and reduces the risk of coronary artery disease. Unfortunately, targeting ANGPTL4 for the therapeutic management of dyslipidemia and atherosclerosis is hampered by the observation that mice and monkeys in which ANGPTL4 is inactivated exhibit lipid accumulation in the mesenteric lymph nodes (MLNs). In mice these pathological events exclusively unfold upon feeding a high saturated FA diet and are followed by an ultimately lethal pro-inflammatory response and chylous ascites. Here, we show that Angptl4-/- mice fed a diet rich in trans FAs develop numerous lipid-filled giant cells in their MLNs, yet do not have elevated serum amyloid and haptoglobin, do not exhibit ascites, and survive, unlike Angptl4-/- mice fed a saturated FA-rich diet. In RAW264.7 macrophages, the saturated FA, palmitate, markedly increased markers of inflammation and the unfolded protein response, whereas the trans-unsaturated elaidate and the cis-unsaturated oleate had the opposite effect. In conclusion, trans and saturated FAs have very distinct biological effects in macrophages. Furthermore, lipid accumulation in MLNs is uncoupled from activation of an acute-phase response and chylous ascites, suggesting that ANGPTL4 should not be fully dismissed as target for dyslipidemia.
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Affiliation(s)
- Antwi-Boasiako Oteng
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Asmita Bhattacharya
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Susanne Brodesser
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Lipidomics Core Facility, University of Cologne, Cologne, Germany
| | - Ling Qi
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Nguan Soon Tan
- School of Biological Sciences and Lee Kong Chian School of Medicine, Nanyang Technological University, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, and KK Research Centre, KK Women's and Children's Hospital, Singapore
| | - Sander Kersten
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands .,Division of Nutritional Sciences, Cornell University, Ithaca, NY
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36
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Ballweg S, Ernst R. Control of membrane fluidity: the OLE pathway in focus. Biol Chem 2017; 398:215-228. [DOI: 10.1515/hsz-2016-0277] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/18/2016] [Indexed: 11/15/2022]
Abstract
Abstract
The maintenance of a fluid lipid bilayer is key for membrane integrity and cell viability. We are only beginning to understand how eukaryotic cells sense and maintain the characteristic lipid compositions and bulk membrane properties of their organelles. One of the key factors determining membrane fluidity and phase behavior is the proportion of saturated and unsaturated acyl chains in membrane lipids. Saccharomyces cerevisiae is an ideal model organism to study the regulation of the lipid acyl chain composition via the OLE pathway. The OLE pathway comprises all steps involved in the regulated mobilization of the transcription factors Mga2 and Spt23 from the endoplasmic reticulum (ER), which then drive the expression of OLE1 in the nucleus. OLE1 encodes for the essential Δ9-fatty acid desaturase Ole1 and is crucial for de novo biosynthesis of unsaturated fatty acids (UFAs) that are used as lipid building blocks. This review summarizes our current knowledge of the OLE pathway, the best-characterized, eukaryotic sense-and-control system regulating membrane lipid saturation, and identifies open questions to indicate future directions.
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37
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Arlia-Ciommo A, Svistkova V, Mohtashami S, Titorenko VI. A novel approach to the discovery of anti-tumor pharmaceuticals: searching for activators of liponecrosis. Oncotarget 2017; 7:5204-25. [PMID: 26636650 PMCID: PMC4868681 DOI: 10.18632/oncotarget.6440] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/21/2015] [Indexed: 02/04/2023] Open
Abstract
A recently conducted chemical genetic screen for pharmaceuticals that can extend longevity of the yeast Saccharomyces cerevisiae has identified lithocholic acid as a potent anti-aging molecule. It was found that this hydrophobic bile acid is also a selective anti-tumor chemical compound; it kills different types of cultured cancer cells if used at concentrations that do not compromise the viability of non-cancerous cells. These studies have revealed that yeast can be successfully used as a model organism for high-throughput screens aimed at the discovery of selectively acting anti-tumor small molecules. Two metabolic traits of rapidly proliferating fermenting yeast, namely aerobic glycolysis and lipogenesis, are known to be similar to those of cancer cells. The mechanisms underlying these key metabolic features of cancer cells and fermenting yeast have been established; such mechanisms are discussed in this review. We also suggest how a yeast-based chemical genetic screen can be used for the high-throughput development of selective anti-tumor pharmaceuticals that kill only cancer cells. This screen consists of searching for chemical compounds capable of increasing the abundance of membrane lipids enriched in unsaturated fatty acids that would therefore be toxic only to rapidly proliferating cells, such as cancer cells and fermenting yeast.
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Affiliation(s)
| | | | - Sadaf Mohtashami
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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38
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Cai M, Wang H, Li JJ, Zhang YL, Xin L, Li F, Lou SJ. The signaling mechanisms of hippocampal endoplasmic reticulum stress affecting neuronal plasticity-related protein levels in high fat diet-induced obese rats and the regulation of aerobic exercise. Brain Behav Immun 2016; 57:347-359. [PMID: 27189035 DOI: 10.1016/j.bbi.2016.05.010] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/12/2016] [Accepted: 05/13/2016] [Indexed: 12/24/2022] Open
Abstract
High fat diet (HFD)-induced obesity has been shown to reduce the levels of neuronal plasticity-related proteins, specifically brain-derived neurotrophic factor (BDNF) and synaptophysin (SYN), in the hippocampus. However, the underlying mechanisms are not fully clear. Endoplasmic reticulum stress (ERS) has been reported to play a key role in regulating gene expression and protein production by affecting stress signaling pathways and ER functions of protein folding and post-translational modification in peripheral tissues of obese rodent models. Additionally, HFD that is associated with hyperglycemia could induce hippocampal ERS, thus impairing insulin signaling and cognitive health in HFD mice. One goal of this study was to determine whether hyperglycemia and hyperlipidemia could cause hippocampal ERS in HFD-induced obese SD rats, and explore the potential mechanisms of ERS regulating hippocampal BDNF and SYN proteins production. Additionally, although regular aerobic exercise could reduce central inflammation and elevate hippocampal BDNF and SYN levels in obese rats, the regulated mechanisms are poorly understood. Nrf2-HO-1 pathways play roles in anti-ERS, anti-inflammation and anti-apoptosis in peripheral tissues. Therefore, the other goal of this study was to determine whether aerobic exercise could activate Nrf2-HO-1 in hippocampus to alleviate obesity-induced hippocampal ERS, which would lead to increased BDNF and SYN levels. Male SD rats were fed on HFD for 8weeks to establish the obese model. Then, 8weeks of aerobic exercise treadmill intervention was arranged for the obese rats. Results showed that HFD-induced obesity caused hyperglycemia and hyperlipidemia, and significantly promoted hippocampal glucose transporter 3 (GLUT3) and fatty acid transport protein 1 (FATP1) protein expression. These results were associated with the activation of hippocampal ERS and ERS-mediated apoptosis. At the same time, we found that excessive hippocampal ERS not only significantly decreased proBDNF-the precursor of mature BDNF, but also attenuated p38/ERK-CREB signaling pathways and activated NLRP3-IL-1β pathways in obese rats. These results were associated with reduced BDNF and SYN protein production. However, these adverse changes were obviously reversed by aerobic exercise intervention through activating the Nrf2-HO-1 pathways. These results suggest that dietary obesity could induce hippocampal ERS in male SD rats, and excessive hippocampal ERS plays a critical role in decreasing the levels of BDNF and SYN. Moreover, aerobic exercise could activate hippocampal Nrf2 and HO-1 to relieve ERS and heighten BDNF and SYN production in obese rats.
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Affiliation(s)
- Ming Cai
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Hong Wang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China; College of Rehabilitation Sciences, Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Jing-Jing Li
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Yun-Li Zhang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Lei Xin
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Feng Li
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Shu-Jie Lou
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China.
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Audagnotto M, Lemmin T, Barducci A, Dal Peraro M. Effect of the Synaptic Plasma Membrane on the Stability of the Amyloid Precursor Protein Homodimer. J Phys Chem Lett 2016; 7:3572-3578. [PMID: 27518597 DOI: 10.1021/acs.jpclett.6b01721] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The proteolytic cleavage of the transmembrane (TM) domain of the amyloid precursor protein (APP) releases amyloid-β (Aβ) peptides, which accumulation in the brain tissue is an early indicator of Alzheimer's disease. We used multiscale molecular dynamics simulations to investigate the stability of APP-TM dimer in realistic models of the synaptic plasma membrane (SPM). Between the two possible dimerization motifs proposed by NMR and EPR, namely G709XXXA713 and G700XXXG704XXXG708, our study revealed that the dimer promoted by the G709XXXA713 motif is not stable in the SPM due to the competition with highly unsaturated lipids that constitute the SPM. Under the same conditions, the dimer promoted by the G700XXXG704XXXG708 motif is instead the most stable species and likely the most biologically relevant. Independently of the dimerization state, both these motifs can be involved in the recruitment of cholesterol molecules.
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Affiliation(s)
- Martina Audagnotto
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland
- Swiss Institute of Bioinformatics (SIB) , Lausanne 1015, Switzerland
| | - Thomas Lemmin
- Department of Pharmaceutical Chemistry, University of California-San Francisco , San Francisco, California 94143, United States
| | - Alessandro Barducci
- Inserm, U1054 Montpellier, France
- Université de Montpellier, CNRS, UMR 5048 , Centre de Biochimie Structurale, U1054 Montpellier, France
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland
- Swiss Institute of Bioinformatics (SIB) , Lausanne 1015, Switzerland
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Covino R, Ballweg S, Stordeur C, Michaelis J, Puth K, Wernig F, Bahrami A, Ernst A, Hummer G, Ernst R. A Eukaryotic Sensor for Membrane Lipid Saturation. Mol Cell 2016; 63:49-59. [DOI: 10.1016/j.molcel.2016.05.015] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/12/2016] [Accepted: 05/11/2016] [Indexed: 12/22/2022]
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Ferru-Clément R, Spanova M, Dhayal S, Morgan NG, Hélye R, Becq F, Hirose H, Antonny B, Vamparys L, Fuchs PFJ, Ferreira T. Targeting surface voids to counter membrane disorders in lipointoxication-related diseases. J Cell Sci 2016; 129:2368-81. [PMID: 27142833 DOI: 10.1242/jcs.183590] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/26/2016] [Indexed: 01/01/2023] Open
Abstract
Saturated fatty acids (SFA), which are abundant in the so-called western diet, have been shown to efficiently incorporate within membrane phospholipids and therefore impact on organelle integrity and function in many cell types. In the present study, we have developed a yeast-based two-step assay and a virtual screening strategy to identify new drugs able to counter SFA-mediated lipointoxication. The compounds identified here were effective in relieving lipointoxication in mammalian β-cells, one of the main targets of SFA toxicity in humans. In vitro reconstitutions and molecular dynamics simulations on bilayers revealed that these molecules, albeit according to different mechanisms, can generate voids at the membrane surface. The resulting surface defects correlate with the recruitment of loose lipid packing or void-sensing proteins required for vesicular budding, a central cellular process that is precluded under SFA accumulation. Taken together, the results presented here point at modulation of surface voids as a central parameter to consider in order to counter the impacts of SFA on cell function.
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Affiliation(s)
- Romain Ferru-Clément
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France Société d'Accélération du Transfert de Technologie (SATT) Grand Centre, 8 rue Pablo Picasso, Clermont-Ferrand 63000, France
| | - Miroslava Spanova
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France
| | - Shalinee Dhayal
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Noel G Morgan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Reynald Hélye
- Société d'Accélération du Transfert de Technologie (SATT) Grand Centre, 8 rue Pablo Picasso, Clermont-Ferrand 63000, France
| | - Frédéric Becq
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France
| | - Hisaaki Hirose
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Université de Nice Sofia-Antipolis, 660 route des Lucioles, Valbonne 06560, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 7275, Université de Nice Sofia-Antipolis, 660 route des Lucioles, Valbonne 06560, France
| | - Lydie Vamparys
- Dynamique des membranes et trafic intracellulaire, Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, Paris 75013, France
| | - Patrick F J Fuchs
- Dynamique des membranes et trafic intracellulaire, Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, Paris 75013, France
| | - Thierry Ferreira
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM), CNRS ERL 7368, Université de Poitiers, 1, rue Georges Bonnet, Poitiers Cedex 9 86073, France
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Valachovic M, Garaiova M, Holic R, Hapala I. Squalene is lipotoxic to yeast cells defective in lipid droplet biogenesis. Biochem Biophys Res Commun 2015; 469:1123-8. [PMID: 26703208 DOI: 10.1016/j.bbrc.2015.12.050] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 12/13/2015] [Indexed: 12/01/2022]
Abstract
The toxic effect of overloaded lipids on cell physiology and viability was described in various organisms. In this study we focused on the potential lipotoxicity of squalene, a linear triterpene synthesized in eukaryotic cells as an intermediate in sterol biosynthesis. Squalene toxicity was studied in the yeast Saccharomyces cerevisiae, a model unicellular eukaryote established in lipotoxicity studies. Squalene levels in yeast are typically low but its accumulation can be induced under specific conditions, e.g. by inhibition of squalene monooxygenase with the antimycotic terbinafine. At higher levels squalene is stored in lipid droplets. We demonstrated that low doses of terbinafine caused severe impairment of growth and loss of viability of the yeast mutant dga1Δ lro1Δ are1Δ are2Δ unable to form lipid droplets and that these defects were linked to squalene accumulation. The hypersensitivity of the lipid droplet-less mutant to terbinafine was alleviated by decreasing squalene accumulation with low doses of squalene synthase inhibitor zaragozic acid. Our results proved that accumulated squalene is lipotoxic to yeast cells if it cannot be efficiently sequestered in lipid droplets. This supports the hypothesis about the role of squalene in the fungicidal activity of terbinafine. Squalene toxicity may represent also a limiting factor for production of this high-value lipid in yeast.
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Affiliation(s)
- Martin Valachovic
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 90028 Ivanka pri Dunaji, Slovak Republic
| | - Martina Garaiova
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 90028 Ivanka pri Dunaji, Slovak Republic
| | - Roman Holic
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 90028 Ivanka pri Dunaji, Slovak Republic
| | - Ivan Hapala
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 90028 Ivanka pri Dunaji, Slovak Republic.
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Gustavo Vazquez-Jimenez J, Chavez-Reyes J, Romero-Garcia T, Zarain-Herzberg A, Valdes-Flores J, Manuel Galindo-Rosales J, Rueda A, Guerrero-Hernandez A, Olivares-Reyes JA. Palmitic acid but not palmitoleic acid induces insulin resistance in a human endothelial cell line by decreasing SERCA pump expression. Cell Signal 2015; 28:53-9. [PMID: 26475209 DOI: 10.1016/j.cellsig.2015.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 09/05/2015] [Accepted: 10/11/2015] [Indexed: 10/22/2022]
Abstract
Palmitic acid is a negative regulator of insulin activity. At the molecular level, palmitic acid reduces insulin stimulated Akt Ser473 phosphorylation. Interestingly, we have found that incubation with palmitic acid of human umbilical vein endothelial cells induced a biphasic effect, an initial transient elevation followed by a sustained reduction of SERCA pump protein levels. However, palmitic acid produced a sustained inhibition of SERCA pump ATPase activity. Insulin resistance state appeared before there was a significant reduction of SERCA2 expression. The mechanism by which palmitic acid impairs insulin signaling may involve endoplasmic reticulum stress, because this fatty acid induced activation of both PERK, an ER stress marker, and JNK, a kinase associated with insulin resistance. None of these effects were observed by incubating HUVEC-CS cells with palmitoleic acid. Importantly, SERCA2 overexpression decreased the palmitic acid-induced insulin resistance state. All these results suggest that SERCA pump might be the target of palmitic acid to induce the insulin resistance state in a human vascular endothelial cell line. Importantly, these data suggest that HUVEC-CS cells respond to palmitic acid-exposure with a compensatory overexpression of SERCA pump within the first hour, which eventually fades out and insulin resistance prevails.
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Affiliation(s)
- J Gustavo Vazquez-Jimenez
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - Jesus Chavez-Reyes
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - Tatiana Romero-Garcia
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - Angel Zarain-Herzberg
- Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, DF 04510, Mexico
| | - Jesus Valdes-Flores
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - J Manuel Galindo-Rosales
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - Angelica Rueda
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - Agustin Guerrero-Hernandez
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico
| | - J Alberto Olivares-Reyes
- Department of Biochemistry, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico DF 07360, Mexico.
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Antonny B, Vanni S, Shindou H, Ferreira T. From zero to six double bonds: phospholipid unsaturation and organelle function. Trends Cell Biol 2015; 25:427-36. [DOI: 10.1016/j.tcb.2015.03.004] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/19/2015] [Accepted: 03/23/2015] [Indexed: 01/21/2023]
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Purdy JG, Shenk T, Rabinowitz JD. Fatty acid elongase 7 catalyzes lipidome remodeling essential for human cytomegalovirus replication. Cell Rep 2015; 10:1375-85. [PMID: 25732827 PMCID: PMC4354725 DOI: 10.1016/j.celrep.2015.02.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/23/2014] [Accepted: 01/29/2015] [Indexed: 11/26/2022] Open
Abstract
Human cytomegalovirus (HCMV) infection rewires host cell metabolism, up-regulating flux from glucose into acetyl-CoA to feed fatty acid metabolism, with saturated very long-chain fatty acids (VLFCA) required for production of infectious virion progeny. The human genome encodes seven elongase enzymes (ELOVL) that extend long chain fatty acids into VLCFA. Here we identify ELOVL7 as pivotal for HCMV infection. HCMV induces ELOVL7 by more than 150-fold. This induction is dependent on mTOR and SREBP-1. ELOVL7 knockdown or mTOR inhibition impairs HCMV-induced fatty acid elongation, HCMV particle release, and infectivity per particle. ELOVL7 overexpression enhances HCMV replication. During HCMV infection, mTOR activity is maintained by the viral protein pUL38. Expression of pUL38 is sufficient to induce ELOVL7, and pUL38-deficient virus is partially defective in ELOVL7 induction and fatty acid elongation. Thus, through its ability to modulate mTOR and SREBP-1, HCMV induces ELOVL7 to synthesize the saturated VLCFA required for efficient virus replication.
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Affiliation(s)
- John G Purdy
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Thomas Shenk
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
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Askari M, Darabi M, Zare Mahmudabadi R, Oboodiat M, Fayezi S, Mostakhdemin Hosseini Z, Pirzadeh A. Tissue fatty acid composition and secretory phospholipase-A2 activity in oral squamous cell carcinoma. Clin Transl Oncol 2014; 17:378-83. [PMID: 25351172 DOI: 10.1007/s12094-014-1242-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/03/2014] [Indexed: 12/19/2022]
Abstract
PURPOSE Oral squamous cell carcinoma (OSCC) is a remarkable health problem worldwide, but its pathogenesis remains unknown. The aim of this study was to compare fat composition and secretory phospholipase-A2 (sPLA2) activity between the malignant and adjacent normal squamous tissues in patients with OSCC. METHODS Paired samples of malignant squamous and adjacent normal-appearing tissues were collected from 27 patients with OSCC. The fatty acid composition in the obtained tissues was determined by gas liquid chromatography. Tissue enzyme activities of sPLA2 were measured using the standard assay with Diheptanoyl Thio-Phosphatidylcholine as substrate. RESULTS In the OSCC tissue, the level of stearic acid (18:0) and activity of sPLA2 were higher (P < 0.001), and the levels of oleic acid (18:1n-9) and linoleic acid (18:2n-6) were lower than that in the adjacent normal-appearing squamous tissue (P < 0.001). The activity of sPLA2 in OSCC was strongly negatively correlated with the amount of 18:2n-6 (r = -0.41, P < 0.001). Negative significant associations were observed between the OSCC invasion and tissue levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHE). CONCLUSION The changes in the fatty acid composition and sPLA2 activity may be regarded as indicators of altered lipid metabolism occurring in vivo during squamous cell carcinogenesis.
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Affiliation(s)
- M Askari
- Department of Maxillofacial Pathology, Faculty of Dentistry, International Campus, Tehran University of Medical Sciences, Tehran, Iran
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Vanni S, Hirose H, Barelli H, Antonny B, Gautier R. A sub-nanometre view of how membrane curvature and composition modulate lipid packing and protein recruitment. Nat Commun 2014; 5:4916. [PMID: 25222832 DOI: 10.1038/ncomms5916] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 08/05/2014] [Indexed: 02/07/2023] Open
Abstract
Two parameters of biological membranes, curvature and lipid composition, direct the recruitment of many peripheral proteins to cellular organelles. Although these traits are often studied independently, it is their combination that generates the unique interfacial properties of cellular membranes. Here, we use a combination of in vivo, in vitro and in silico approaches to provide a comprehensive map of how these parameters modulate membrane adhesive properties. The correlation between the membrane partitioning of model amphipathic helices and the distribution of lipid-packing defects in membranes of different shape and composition explains how macroscopic membrane properties modulate protein recruitment by changing the molecular topography of the membrane interfacial region. Furthermore, our results suggest that the range of conditions that can be obtained in a cellular context is remarkably large because lipid composition and curvature have, under most circumstances, cumulative effects.
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Affiliation(s)
- Stefano Vanni
- 1] Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 660 route des Lucioles, 06560 Valbonne, France [2]
| | - Hisaaki Hirose
- 1] Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 660 route des Lucioles, 06560 Valbonne, France [2]
| | - Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 660 route des Lucioles, 06560 Valbonne, France
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 660 route des Lucioles, 06560 Valbonne, France
| | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 660 route des Lucioles, 06560 Valbonne, France
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Lipid landscapes and pipelines in membrane homeostasis. Nature 2014; 510:48-57. [DOI: 10.1038/nature13474] [Citation(s) in RCA: 743] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 04/03/2014] [Indexed: 11/08/2022]
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Leamy AK, Egnatchik RA, Shiota M, Ivanova PT, Myers DS, Brown HA, Young JD. Enhanced synthesis of saturated phospholipids is associated with ER stress and lipotoxicity in palmitate treated hepatic cells. J Lipid Res 2014; 55:1478-88. [PMID: 24859739 DOI: 10.1194/jlr.m050237] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Indexed: 01/22/2023] Open
Abstract
High levels of saturated FAs (SFAs) are acutely toxic to a variety of cell types, including hepatocytes, and have been associated with diseases such as type 2 diabetes and nonalcoholic fatty liver disease. SFA accumulation has been previously shown to degrade endoplasmic reticulum (ER) function leading to other manifestations of the lipoapoptotic cascade. We hypothesized that dysfunctional phospholipid (PL) metabolism is an initiating factor in this ER stress response. Treatment of either primary hepatocytes or H4IIEC3 cells with the SFA palmitate resulted in dramatic dilation of the ER membrane, coinciding with other markers of organelle dysfunction. This was accompanied by increased de novo glycerolipid synthesis, significant elevation of dipalmitoyl phosphatidic acid, diacylglycerol, and total PL content in H4IIEC3 cells. Supplementation with oleate (OA) reversed these markers of palmitate (PA)-induced lipotoxicity. OA/PA cotreatment modulated the distribution of PA between lipid classes, increasing the flux toward triacylglycerols while reducing its incorporation into PLs. Similar trends were demonstrated in both primary hepatocytes and the H4IIEC3 hepatoma cell line. Overall, these findings suggest that modifying the FA composition of structural PLs can protect hepatocytes from PA-induced ER stress and associated lipotoxicity.
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Affiliation(s)
- Alexandra K Leamy
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604
| | - Robert A Egnatchik
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604
| | - Masakazu Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235-1604
| | - Pavlina T Ivanova
- Department of Pharmacology, Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN 37235-1604
| | - David S Myers
- Department of Pharmacology, Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN 37235-1604
| | - H Alex Brown
- Department of Pharmacology, Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN 37235-1604 Department of Biochemistry, Vanderbilt University, Nashville, TN 37235-1604 Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1604
| | - Jamey D Young
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235-1604 Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235-1604
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Activation of the endoplasmic reticulum unfolded protein response by lipid disequilibrium without disturbed proteostasis in vivo. Proc Natl Acad Sci U S A 2014; 111:E2271-80. [PMID: 24843123 DOI: 10.1073/pnas.1318262111] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The Mediator is a conserved transcriptional coregulator complex required for eukaryotic gene expression. In Caenorhabditis elegans, the Mediator subunit mdt-15 is essential for the expression of genes involved in fatty acid metabolism and ingestion-associated stress responses. mdt-15 loss of function causes defects in reproduction and mobility and shortens lifespan. In the present study, we find that worms with mutated or depleted mdt-15 (mdt-15 worms) exhibit decreased membrane phospholipid desaturation, especially in phosphatidylcholine. Accordingly, mdt-15 worms exhibit disturbed endoplasmic reticulum (ER) homeostasis, as indicated by a constitutively activated ER unfolded protein response (UPR(ER)). Activation of this stress response is only partially the consequence of reduced membrane lipid desaturation, implicating other mdt-15-regulated processes in maintaining ER homeostasis. Interestingly, mdt-15 inactivation or depletion of the lipid metabolism enzymes stearoyl-CoA-desaturases (SCD) and S-adenosyl methionine synthetase (sams-1) activates the UPR(ER) without promoting misfolded protein aggregates. Moreover, these worms exhibit wild-type sensitivity to chemically induced protein misfolding, and they do not display synthetic lethality with mutations in UPR(ER) genes, which cause protein misfolding. Therefore, the constitutively activated UPR(ER) in mdt-15, SCD, and sams-1 worms is not the consequence of proteotoxic stress but likely is the direct result of changes in ER membrane fluidity and composition. Together, our data suggest that the UPR(ER) is induced directly upon membrane disequilibrium and thus monitors altered ER homeostasis.
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