1
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Chen M, Ghelfi M, Poon JF, Jeon N, Boccalon N, Rubsamen M, Valentino S, Mehta V, Stamper M, Tariq H, Zunica E, Ulatowski L, Chung S, Fritz C, Cameron M, Cameron C, Pratt DA, Atkinson J, Finno CJ, Manor D. Antioxidant-independent activities of alpha-tocopherol. J Biol Chem 2025; 301:108327. [PMID: 39978678 PMCID: PMC11968272 DOI: 10.1016/j.jbc.2025.108327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2024] [Revised: 01/28/2025] [Accepted: 02/13/2025] [Indexed: 02/22/2025] Open
Abstract
Alpha-tocopherol (vitamin E) is a plant-derived dietary lipid that is essential for the health of most animals, including humans. Originally discovered as a fertility factor in rodents, the primary health-promoting properties of the vitamin in humans was shown to be protection of neuromuscular functions. Heritable vitamin E deficiency manifests in spinocerebellar ataxia that can be stabilized by timely supplementation with high-dose α-tocopherol. The molecular basis for α-tocopherol's biological activities has been attributed primarily to the vitamin's efficacy in preventing lipid peroxidation in membranes and lipoproteins, but the possibility that the vitamin possesses additional biological activities has been postulated and debated in the literature without conclusive resolution. We designed and synthesized a novel analog of α-tocopherol, 6-hydroxymethyl α-tocopherol (6-HMTC), which retains most of the vitamin's structural, physical, and biochemical properties, yet lacks measurable radical-trapping antioxidant activity. 6-HMTC bound to the tocopherol transfer protein with high (nanomolar) affinity, like that of the natural vitamin, attesting to the analog's preservation of structural integrity. Yet, 6-HMTC did not inhibit lipid peroxidation or associated ferroptotic cell death. Notably, 6-HMTC modulated the expression of some genes in a manner essentially identical to that exhibited by α-tocopherol. These findings support the notion that α-tocopherol modulates gene expression via an antioxidant-independent mechanism.
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Affiliation(s)
- Matthew Chen
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mikel Ghelfi
- Department of Chemistry, Brock University, Ontario, Canada
| | - Jia-Fei Poon
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Nayeon Jeon
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | | | - Michael Rubsamen
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Stephen Valentino
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Vansh Mehta
- Department of Chemistry, Brock University, Ontario, Canada
| | - Michaela Stamper
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Hamza Tariq
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Elizabeth Zunica
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Lynn Ulatowski
- Department of Biology, Ursuline College, Pepper Pike, Ohio, USA
| | - Stacey Chung
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Claire Fritz
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mark Cameron
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Cheryl Cameron
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA
| | - Derek A Pratt
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Carrie J Finno
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Danny Manor
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio, USA.
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2
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Barrantes FJ. The pleomorphic cholesterol sensing motifs of transmembrane proteins. Chem Phys Lipids 2025; 266:105460. [PMID: 39615777 DOI: 10.1016/j.chemphyslip.2024.105460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2024] [Revised: 11/25/2024] [Accepted: 11/27/2024] [Indexed: 01/11/2025]
Abstract
Millions of years of phylogenetic evolution have shaped the crosstalk between sterols and membrane-embedded proteins. This lengthy process, which began before the appearance of eukaryotic cells, has sculpted the two types of molecules to cover a wide spectrum of structural interconnectedness, ranging from rapid touch-and-go hits of low-affinity between surfaces to stronger lock-and-key type structural contacts. The former usually involve relatively loose contacts between linear amino acid sequences on the membrane-exposed transmembrane domains of the protein, readily accessible to the sterols as they briefly visit clefts between adjacent transmembrane segments while in rapid exchange with the bulk lipid bilayer. This operational mode is probably the most ancestral one, since it was already present in primitive bacteria interacting with hopanoid lipids. At the other end of this spectrum are more complex cholesterol binding sites that have required the acquisition of complex 3D non-sequential segments of the membrane protein to establish stereochemically elaborate 3D designs complementary to the rough and smooth surfaces of the eukaryotic neutral lipid, cholesterol. This short review explores cholesterol-membrane protein interactions using membrane protein paradigms having in common their participation in intercellular communications neurotransmission, hormone signalling, amino acid/neurotransmitter transport- and in cancer.
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Affiliation(s)
- Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute, UCA-CONICET, Buenos Aires C1107AAF, Argentina.
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3
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Yilmaz S, Cizmecioglu O. PI3K Signaling at the Crossroads of Lipid Metabolism and Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2025; 1479:139-164. [PMID: 39616584 DOI: 10.1007/5584_2024_832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2025]
Abstract
The proto-oncogenic PI3K pathway is crucial for the integration of growth factor signaling and metabolic pathways to facilitate the coordination for cell growth. Since transformed cells have the ability to upregulate their anabolic pathways and selectively modulate a subset of metabolites functioning as anti- or pro-tumorigenic signal mediators, the question of how the levels of these metabolites are regulated has also become the center of attention for cancer researchers. Apart from its well-defined roles in glucose metabolism and peptide anabolism, the PI3K pathway appears to be a significant regulator of lipid metabolism and a potentiator of proto-oncogenic bioactive lipid metabolite signaling. In this review, we aim to describe the crosstalk between the PI3K pathway and bioactive lipid species of the three main lipid classes.
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Affiliation(s)
- Sevval Yilmaz
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Onur Cizmecioglu
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.
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4
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Rong S, Xia M, Vale G, Wang S, Kim CW, Li S, McDonald JG, Radhakrishnan A, Horton JD. DGAT2 inhibition blocks SREBP-1 cleavage and improves hepatic steatosis by increasing phosphatidylethanolamine in the ER. Cell Metab 2024; 36:617-629.e7. [PMID: 38340721 PMCID: PMC10939742 DOI: 10.1016/j.cmet.2024.01.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 11/28/2023] [Accepted: 01/18/2024] [Indexed: 02/12/2024]
Abstract
Diacylglycerol acyltransferase 2 (DGAT2) catalyzes the final step of triglyceride (TG) synthesis. DGAT2 deletion in mice lowers liver TGs, and DGAT2 inhibitors are under investigation for the treatment of fatty liver disease. Here, we show that DGAT2 inhibition also suppressed SREBP-1 cleavage, reduced fatty acid synthesis, and lowered TG accumulation and secretion from liver. DGAT2 inhibition increased phosphatidylethanolamine (PE) levels in the endoplasmic reticulum (ER) and inhibited SREBP-1 cleavage, while DGAT2 overexpression lowered ER PE concentrations and increased SREBP-1 cleavage in vivo. ER enrichment with PE blocked SREBP-1 cleavage independent of Insigs, which are ER proteins that normally retain SREBPs in the ER. Thus, inhibition of DGAT2 shunted diacylglycerol into phospholipid synthesis, increasing the PE content of the ER, resulting in reduced SREBP-1 cleavage and less hepatic steatosis. This study reveals a new mechanism that regulates SREBP-1 activation and lipogenesis that is independent of sterols and SREBP-2 in liver.
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Affiliation(s)
- Shunxing Rong
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Mingfeng Xia
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Goncalo Vale
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Simeng Wang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Chai-Wan Kim
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Shili Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Jeffrey G McDonald
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Arun Radhakrishnan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA
| | - Jay D Horton
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA.
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5
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Xu S, Smothers JC, Rye D, Endapally S, Chen H, Li S, Liang G, Kinnebrew M, Rohatgi R, Posner BA, Radhakrishnan A. A cholesterol-binding bacterial toxin provides a strategy for identifying a specific Scap inhibitor that blocks lipid synthesis in animal cells. Proc Natl Acad Sci U S A 2024; 121:e2318024121. [PMID: 38330014 PMCID: PMC10873635 DOI: 10.1073/pnas.2318024121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/15/2023] [Indexed: 02/10/2024] Open
Abstract
Lipid synthesis is regulated by the actions of Scap, a polytopic membrane protein that binds cholesterol in membranes of the endoplasmic reticulum (ER). When ER cholesterol levels are low, Scap activates SREBPs, transcription factors that upregulate genes for synthesis of cholesterol, fatty acids, and triglycerides. When ER cholesterol levels rise, the sterol binds to Scap, triggering conformational changes that prevent activation of SREBPs and halting synthesis of lipids. To achieve a molecular understanding of how cholesterol regulates the Scap/SREBP machine and to identify therapeutics for dysregulated lipid metabolism, cholesterol-mimetic compounds that specifically bind and inhibit Scap are needed. To accomplish this goal, we focused on Anthrolysin O (ALO), a pore-forming bacterial toxin that binds cholesterol with a specificity and sensitivity that is uncannily similar to Scap. We reasoned that a small molecule that would bind and inhibit ALO might also inhibit Scap. High-throughput screening of a ~300,000-compound library for ALO-binding unearthed one molecule, termed UT-59, which binds to Scap's cholesterol-binding site. Upon binding, UT-59 triggers the same conformation changes in Scap as those induced by cholesterol and blocks activation of SREBPs and lipogenesis in cultured cells. UT-59 also inhibits SREBP activation in the mouse liver. Unlike five previously reported inhibitors of SREBP activation, UT-59 is the only one that acts specifically by binding to Scap's cholesterol-binding site. Our approach to identify specific Scap inhibitors such as UT-59 holds great promise in developing therapeutic leads for human diseases stemming from elevated SREBP activation, such as fatty liver and certain cancers.
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Affiliation(s)
- Shimeng Xu
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Jared C. Smothers
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Daphne Rye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Shreya Endapally
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Hong Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Shili Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Guosheng Liang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Maia Kinnebrew
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - Bruce A. Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Arun Radhakrishnan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
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6
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Coradini D. Impact of De Novo Cholesterol Biosynthesis on the Initiation and Progression of Breast Cancer. Biomolecules 2024; 14:64. [PMID: 38254664 PMCID: PMC10813427 DOI: 10.3390/biom14010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/26/2023] [Accepted: 01/01/2024] [Indexed: 01/24/2024] Open
Abstract
Cholesterol (CHOL) is a multifaceted lipid molecule. It is an essential structural component of cell membranes, where it cooperates in regulating the intracellular trafficking and signaling pathways. Additionally, it serves as a precursor for vital biomolecules, including steroid hormones, isoprenoids, vitamin D, and bile acids. Although CHOL is normally uptaken from the bloodstream, cells can synthesize it de novo in response to an increased requirement due to physiological tissue remodeling or abnormal proliferation, such as in cancer. Cumulating evidence indicated that increased CHOL biosynthesis is a common feature of breast cancer and is associated with the neoplastic transformation of normal mammary epithelial cells. After an overview of the multiple biological activities of CHOL and its derivatives, this review will address the impact of de novo CHOL production on the promotion of breast cancer with a focus on mammary stem cells. The review will also discuss the effect of de novo CHOL production on in situ and invasive carcinoma and its impact on the response to adjuvant treatment. Finally, the review will discuss the present and future therapeutic strategies to normalize CHOL biosynthesis.
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Affiliation(s)
- Danila Coradini
- Laboratory of Medical Statistics and Biometry, "Giulio A. Maccacaro", Department of Clinical Sciences and Community Health, University of Milan, Campus Cascina Rosa, 20133 Milan, Italy
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7
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Bolshette N, Ezagouri S, Dandavate V, Karavaeva I, Golik M, Wang H, Espenshade PJ, Osborne TF, Han X, Asher G. Carbon dioxide regulates cholesterol levels through SREBP2. PLoS Biol 2023; 21:e3002367. [PMID: 37967106 PMCID: PMC10651039 DOI: 10.1371/journal.pbio.3002367] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/06/2023] [Indexed: 11/17/2023] Open
Abstract
In mammals, O2 and CO2 levels are tightly regulated and are altered under various pathological conditions. While the molecular mechanisms that participate in O2 sensing are well characterized, little is known regarding the signaling pathways that participate in CO2 signaling and adaptation. Here, we show that CO2 levels control a distinct cellular transcriptional response that differs from mere pH changes. Unexpectedly, we discovered that CO2 regulates the expression of cholesterogenic genes in a SREBP2-dependent manner and modulates cellular cholesterol accumulation. Molecular dissection of the underlying mechanism suggests that CO2 triggers SREBP2 activation through changes in endoplasmic reticulum (ER) membrane cholesterol levels. Collectively, we propose that SREBP2 participates in CO2 signaling and that cellular cholesterol levels can be modulated by CO2 through SREBP2.
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Affiliation(s)
- Nityanand Bolshette
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Saar Ezagouri
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Vaishnavi Dandavate
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Iuliia Karavaeva
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Marina Golik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Hu Wang
- The Sam & Ann Barshop Institute for Longevity & Aging Studies, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Peter J. Espenshade
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Timothy F. Osborne
- Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, and Medicine in the Division of Endocrinology, Diabetes and Metabolism of the Johns Hopkins University School of Medicine, Petersburg, Florida, United States of America
| | - Xianlin Han
- The Sam & Ann Barshop Institute for Longevity & Aging Studies, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Gad Asher
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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8
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Zhou X, Jin S, Pan J, Lin Q, Yang S, Lu Y, Qiu M, Ambe PC, Basharat Z, Zimmer V, Wang W, Hong W. Relationship between Cholesterol-Related Lipids and Severe Acute Pancreatitis: From Bench to Bedside. J Clin Med 2023; 12:jcm12051729. [PMID: 36902516 PMCID: PMC10003000 DOI: 10.3390/jcm12051729] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/29/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
It is well known that hypercholesterolemia in the body has pro-inflammatory effects through the formation of inflammasomes and augmentation of TLR (Toll-like receptor) signaling, which gives rise to cardiovascular disease and neurodegenerative diseases. However, the interaction between cholesterol-related lipids and acute pancreatitis (AP) has not yet been summarized before. This hinders the consensus on the existence and clinical importance of cholesterol-associated AP. This review focuses on the possible interaction between AP and cholesterol-related lipids, which include total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein (Apo) A1, from the bench to the bedside. With a higher serum level of total cholesterol, LDL-C is associated with the severity of AP, while the persistent inflammation of AP is allied with a decrease in serum levels of cholesterol-related lipids. Therefore, an interaction between cholesterol-related lipids and AP is postulated. Cholesterol-related lipids should be recommended as risk factors and early predictors for measuring the severity of AP. Cholesterol-lowering drugs may play a role in the treatment and prevention of AP with hypercholesterolemia.
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Affiliation(s)
- Xiaoying Zhou
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
- School of the First Clinical Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Shengchun Jin
- School of the First Clinical Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Jingyi Pan
- School of the First Clinical Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Qingyi Lin
- School of the First Clinical Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Shaopeng Yang
- School of the First Clinical Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yajing Lu
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Minhao Qiu
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Peter C. Ambe
- Department of General Surgery, Visceral Surgery and Coloproctology, Vinzenz-Pallotti-Hospital Bensberg, Vinzenz-Pallotti-Str. 20–24, 51429 Bensberg, Germany
| | - Zarrin Basharat
- Jamil-ur-Rahman Center for Genome Research, Dr. Panjwani Centre for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Vincent Zimmer
- Department of Medicine, Marienhausklinik St. Josef Kohlhof, 66539 Neunkirchen, Germany
- Department of Medicine II, Saarland University Medical Center, Saarland University, 66421 Homburg, Germany
| | - Wei Wang
- School of Mental Health, Wenzhou Medical University, Wenzhou 325035, China
| | - Wandong Hong
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
- Correspondence: ; Tel./Fax: +86-0577-55579122
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9
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Yuan Y, Zhu Y, Li Y, Li X, Jiao R, Bai W. Cholesterol-Lowering Activity of Vitisin A Is Mediated by Inhibiting Cholesterol Biosynthesis and Enhancing LDL Uptake in HepG2 Cells. Int J Mol Sci 2023; 24:3301. [PMID: 36834719 PMCID: PMC9961218 DOI: 10.3390/ijms24043301] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/01/2023] [Accepted: 01/18/2023] [Indexed: 02/10/2023] Open
Abstract
Pyranoanthocyanins have been reported to possess better chemical stability and bioactivities than monomeric anthocyanins in some aspects. The hypocholesterolemic activity of pyranoanthocyanins is unclear. In view of this, this study was conducted to compare the cholesterol-lowering activities of Vitisin A with the anthocyanin counterpart Cyanidin-3-O-glucoside(C3G) in HepG2 cells and to investigate the interaction of Vitisin A with the expression of genes and proteins associated with cholesterol metabolism. HepG2 cells were incubated with 40 μM cholesterol and 4 μM 25-hydroxycholeterol with various concentrations of Vitisin A or C3G for 24 h. It was found that Vitisin A decreased the cholesterol levels at the concentrations of 100 μM and 200 μM with a dose-response relationship, while C3G exhibited no significant effect on cellular cholesterol. Furthermore, Vitisin A could down-regulate 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR) to inhibit cholesterol biosynthesis through a sterol regulatory element-binding protein 2 (SREBP2)-dependent mechanism, and up-regulate low-density lipoprotein receptor (LDLR) and blunt the secretion of proprotein convertase subtilisin/kexin type 9 (PCSK9) protein to promote intracellular LDL uptake without LDLR degradation. In conclusion, Vitisin A demonstrated hypocholesterolemic activity, by inhibiting cholesterol biosynthesis and enhancing LDL uptake in HepG2 cells.
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Affiliation(s)
| | | | | | | | - Rui Jiao
- Department of Food Science and Engineering, Institute of Food Safety and Nutrition, Jinan University, Guangzhou 510632, China
| | - Weibin Bai
- Department of Food Science and Engineering, Institute of Food Safety and Nutrition, Jinan University, Guangzhou 510632, China
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10
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Lee AG. The role of cholesterol binding in the control of cholesterol by the Scap-Insig system. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2022; 51:385-399. [PMID: 35717507 PMCID: PMC9233655 DOI: 10.1007/s00249-022-01606-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/26/2022] [Accepted: 06/05/2022] [Indexed: 12/02/2022]
Abstract
Scap and Insig, two proteins embedded in the membrane of the endoplasmic reticulum (ER), regulate the synthesis of cholesterol in animal cells by forming a dimer in the presence of high concentrations of cholesterol. Cryo-electron microscopic structures for the Scap-Insig dimer show a sterol-binding site at the dimer interface, but none of the structures include cholesterol itself. Here, a molecular docking approach developed to characterise cholesterol binding to the transmembrane (TM) regions of membrane proteins is used to characterise cholesterol binding to sites on the TM surface of the dimer and to the interfacial binding site. Binding of cholesterol is also observed at sites on the extra-membranous luminal domains of Scap, but the properties of these sites suggest that they will be unoccupied in vivo. Comparing the structure of Scap in the dimer with that predicted by AlphaFold for monomeric Scap suggests that dimer formation could result in relocation of TM helix 7 of Scap and of the loop between TM6 and 7, and that this could be the key change on Scap that signals that there is a high concentration of cholesterol in the ER.
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Affiliation(s)
- Anthony G Lee
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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11
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Centonze G, Natalini D, Piccolantonio A, Salemme V, Morellato A, Arina P, Riganti C, Defilippi P. Cholesterol and Its Derivatives: Multifaceted Players in Breast Cancer Progression. Front Oncol 2022; 12:906670. [PMID: 35719918 PMCID: PMC9204587 DOI: 10.3389/fonc.2022.906670] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 04/15/2022] [Indexed: 11/13/2022] Open
Abstract
Cholesterol is an essential lipid primarily synthesized in the liver through the mevalonate pathway. Besides being a precursor of steroid hormones, bile acid, and vitamin D, it is an essential structural component of cell membranes, is enriched in membrane lipid rafts, and plays a key role in intracellular signal transduction. The lipid homeostasis is finely regulated end appears to be impaired in several types of tumors, including breast cancer. In this review, we will analyse the multifaceted roles of cholesterol and its derivatives in breast cancer progression. As an example of the bivalent role of cholesterol in the cell membrane of cancer cells, on the one hand, it reduces membrane fluidity, which has been associated with a more aggressive tumor phenotype in terms of cell motility and migration, leading to metastasis formation. On the other hand, it makes the membrane less permeable to small water-soluble molecules that would otherwise freely cross, resulting in a loss of chemotherapeutics permeability. Regarding cholesterol derivatives, a lower vitamin D is associated with an increased risk of breast cancer, while steroid hormones, coupled with the overexpression of their receptors, play a crucial role in breast cancer progression. Despite the role of cholesterol and derivatives molecules in breast cancer development is still controversial, the use of cholesterol targeting drugs like statins and zoledronic acid appears as a challenging promising tool for breast cancer treatment.
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Affiliation(s)
- Giorgia Centonze
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy
| | - Dora Natalini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy
| | - Alessio Piccolantonio
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy
| | - Vincenzo Salemme
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy
| | - Alessandro Morellato
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy
| | - Pietro Arina
- University College London (UCL), Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, United Kingdom
| | - Chiara Riganti
- Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy.,Department of Oncology, University of Torino, Torino, Italy
| | - Paola Defilippi
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Interdepartmental Center of Research in Molecular Biotechnology, University of Torino, Torino, Italy
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12
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Škara L, Huđek Turković A, Pezelj I, Vrtarić A, Sinčić N, Krušlin B, Ulamec M. Prostate Cancer-Focus on Cholesterol. Cancers (Basel) 2021; 13:4696. [PMID: 34572923 PMCID: PMC8469848 DOI: 10.3390/cancers13184696] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/08/2021] [Accepted: 09/15/2021] [Indexed: 12/24/2022] Open
Abstract
Prostate cancer (PC) is the most common malignancy in men. Common characteristic involved in PC pathogenesis are disturbed lipid metabolism and abnormal cholesterol accumulation. Cholesterol can be further utilized for membrane or hormone synthesis while cholesterol biosynthesis intermediates are important for oncogene membrane anchoring, nucleotide synthesis and mitochondrial electron transport. Since cholesterol and its biosynthesis intermediates influence numerous cellular processes, in this review we have described cholesterol homeostasis in a normal cell. Additionally, we have illustrated how commonly deregulated signaling pathways in PC (PI3K/AKT/MTOR, MAPK, AR and p53) are linked with cholesterol homeostasis regulation.
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Affiliation(s)
- Lucija Škara
- Department of Medical Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Group for Research on Epigenetic Biomarkers (Epimark), School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Ana Huđek Turković
- Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia;
| | - Ivan Pezelj
- Department of Urology, University Clinical Hospital Center Sestre Milosrdnice, 10000 Zagreb, Croatia;
| | - Alen Vrtarić
- Department of Clinical Chemistry, University Clinical Hospital Center Sestre Milosrdnice, 10000 Zagreb, Croatia;
| | - Nino Sinčić
- Department of Medical Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Group for Research on Epigenetic Biomarkers (Epimark), School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Božo Krušlin
- Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Ljudevit Jurak Clinical Department of Pathology and Cytology, Sestre Milosrdnice University Hospital Center, 10000 Zagreb, Croatia
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Monika Ulamec
- Group for Research on Epigenetic Biomarkers (Epimark), School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Ljudevit Jurak Clinical Department of Pathology and Cytology, Sestre Milosrdnice University Hospital Center, 10000 Zagreb, Croatia
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
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13
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Kober DL, Radhakrishnan A, Goldstein JL, Brown MS, Clark LD, Bai XC, Rosenbaum DM. Scap structures highlight key role for rotation of intertwined luminal loops in cholesterol sensing. Cell 2021; 184:3689-3701.e22. [PMID: 34139175 PMCID: PMC8277531 DOI: 10.1016/j.cell.2021.05.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/08/2021] [Accepted: 05/14/2021] [Indexed: 11/26/2022]
Abstract
The cholesterol-sensing protein Scap induces cholesterol synthesis by transporting membrane-bound transcription factors called sterol regulatory element-binding proteins (SREBPs) from the endoplasmic reticulum (ER) to the Golgi apparatus for proteolytic activation. Transport requires interaction between Scap's two ER luminal loops (L1 and L7), which flank an intramembrane sterol-sensing domain (SSD). Cholesterol inhibits Scap transport by binding to L1, which triggers Scap's binding to Insig, an ER retention protein. Here we used cryoelectron microscopy (cryo-EM) to elucidate two structures of full-length chicken Scap: (1) a wild-type free of Insigs and (2) mutant Scap bound to chicken Insig without cholesterol. Strikingly, L1 and L7 intertwine tightly to form a globular domain that acts as a luminal platform connecting the SSD to the rest of Scap. In the presence of Insig, this platform undergoes a large rotation accompanied by rearrangement of Scap's transmembrane helices. We postulate that this conformational change halts Scap transport of SREBPs and inhibits cholesterol synthesis.
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Affiliation(s)
- Daniel L Kober
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Arun Radhakrishnan
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Joseph L Goldstein
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Michael S Brown
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lindsay D Clark
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xiao-Chen Bai
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Daniel M Rosenbaum
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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14
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Yan R, Cao P, Song W, Li Y, Wang T, Qian H, Yan C, Yan N. Structural basis for sterol sensing by Scap and Insig. Cell Rep 2021; 35:109299. [PMID: 34192549 DOI: 10.1016/j.celrep.2021.109299] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/29/2021] [Accepted: 06/03/2021] [Indexed: 11/30/2022] Open
Abstract
The sterol regulatory element-binding protein (SREBP) pathway monitors the cellular cholesterol level through sterol-regulated association between the SREBP cleavage-activating protein (Scap) and the insulin-induced gene (Insig). Despite structural determination of the Scap and Insig-2 complex bound to 25-hydroxycholesterol, the luminal domains of Scap remain unresolved. In this study, combining cryogenic electron microscopy (cryo-EM) analysis and artificial intelligence-facilitated structural prediction, we report the structure of the human Scap/Insig-2 complex purified in digitonin. The luminal domain loop 1 and a co-folded segment in loop 7 of Scap resemble those of the luminal/extracellular domain in NPC1 and related proteins, providing clues to the cholesterol-regulated interaction of loop 1 and loop 7. An additional luminal interface is observed between Scap and Insig. We also show that Scap(D428A), which inhibits SREBP activation even under sterol depletion, exhibits an identical conformation with the wild-type protein when complexed with Insig-2, and its constitutive suppression of the SREBP pathway may also involve a later step in protein trafficking.
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Affiliation(s)
- Renhong Yan
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China.
| | - Pingping Cao
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wenqi Song
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yaning Li
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tongtong Wang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongwu Qian
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Chuangye Yan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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15
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Gu Y, Liu X, Liao L, Gao Y, Shi Y, Ni J, He G. Relationship between lipid metabolism and Hedgehog signaling pathway. J Steroid Biochem Mol Biol 2021; 209:105825. [PMID: 33529733 DOI: 10.1016/j.jsbmb.2021.105825] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 10/28/2020] [Accepted: 01/13/2021] [Indexed: 02/08/2023]
Abstract
The Hedgehog (Hh) signaling pathway is highly conserved signaling pathway in cells. Steroids was found to play a vital role in Hh signaling pathway and aberrant Hh signaling was found to lead a series of disease correlate with abnormal lipid metabolism. This paper aimed to elucidate the relationship between lipid metabolism and Hedgehog signaling pathway.
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Affiliation(s)
- Yuan Gu
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Hunan 410011, PR China
| | - Xiaochen Liu
- University of Toledo Medical Center 3000 Arlington Ave. Toledo, OH 43614, USA
| | - Lele Liao
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Hunan 410011, PR China
| | - Yongquan Gao
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Hunan 410011, PR China
| | - Yu Shi
- West China School of Stomatology, Sichuan University, Chengdu 610041, PR China; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Jiangdong Ni
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Hunan 410011, PR China
| | - Guangxu He
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Hunan 410011, PR China.
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16
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Zhou C, He Q, Gan H, Zeng T, Liu Q, Moorhead JF, Varghese Z, Ouyang N, Ruan XZ. Hyperphosphatemia in chronic kidney disease exacerbates atherosclerosis via a mannosidases-mediated complex-type conversion of SCAP N-glycans. Kidney Int 2021; 99:1342-1353. [PMID: 33631226 DOI: 10.1016/j.kint.2021.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 12/31/2022]
Abstract
Blood phosphate levels are linked to atherosclerotic cardiovascular disease in patients with chronic kidney disease (CKD), but the molecular mechanisms remain unclear. Emerging studies indicate an involvement of hyperphosphatemia in CKD accelerated atherogenesis through disturbed cholesterol homeostasis. Here, we investigated a potential atherogenic role of high phosphate concentrations acting through aberrant activation of sterol regulatory element-binding protein (SREBP) and cleavage-activating protein (SCAP)-SREBP2 signaling in patients with CKD, hyperphosphatemic apolipoprotein E (ApoE) knockout mice, and cultured vascular smooth muscle cells. Hyperphosphatemia correlated positively with increased atherosclerotic cardiovascular disease risk in Chinese patients with CKD and severe atheromatous lesions in the aortas of ApoE knockout mice. Mice arteries had elevated SCAP levels with aberrantly activated SCAP-SREBP2 signaling. Excess phosphate in vitro raised the activity of α-mannosidase, resulting in delayed SCAP degradation through promoting complex-type conversion of SCAP N-glycans. The retention of SCAP enhanced transactivation of SREBP2 and expression of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase, boosting intracellular cholesterol synthesis. Elevated α-mannosidase II activity was also observed in the aortas of ApoE knockout mice and the radial arteries of patients with uremia and hyperphosphatemia. High phosphate concentration in vitro elevated α-mannosidase II activity in the Golgi, enhanced complex-type conversion of SCAP N-glycans, thereby upregulating intracellular cholesterol synthesis. Thus, our studies explain how hyperphosphatemia independently accelerates atherosclerosis in CKD.
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Affiliation(s)
- Chao Zhou
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Quan He
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Hua Gan
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Tingting Zeng
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Qiao Liu
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - John F Moorhead
- John Moorhead Research Laboratory, Centre for Nephrology, University College London Medical School, Royal Free Campus, London, United Kingdom
| | - Zac Varghese
- John Moorhead Research Laboratory, Centre for Nephrology, University College London Medical School, Royal Free Campus, London, United Kingdom
| | - Nan Ouyang
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
| | - Xiong Z Ruan
- John Moorhead Research Laboratory, Centre for Nephrology, University College London Medical School, Royal Free Campus, London, United Kingdom; Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, People's Republic of China.
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17
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Yan R, Cao P, Song W, Qian H, Du X, Coates HW, Zhao X, Li Y, Gao S, Gong X, Liu X, Sui J, Lei J, Yang H, Brown AJ, Zhou Q, Yan C, Yan N. A structure of human Scap bound to Insig-2 suggests how their interaction is regulated by sterols. Science 2021; 371:science.abb2224. [PMID: 33446483 DOI: 10.1126/science.abb2224] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 07/31/2020] [Accepted: 01/06/2021] [Indexed: 12/22/2022]
Abstract
The sterol regulatory element-binding protein (SREBP) pathway controls cellular homeostasis of sterols. The key players in this pathway, Scap and Insig-1 and -2, are membrane-embedded sterol sensors. The 25-hydroxycholesterol (25HC)-dependent association of Scap and Insig acts as the master switch for the SREBP pathway. Here, we present cryo-electron microscopy analysis of the human Scap and Insig-2 complex in the presence of 25HC, with the transmembrane (TM) domains determined at an average resolution of 3.7 angstrom. The sterol-sensing domain in Scap and all six TMs in Insig-2 were resolved. A 25HC molecule is sandwiched between the S4 to S6 segments in Scap and TMs 3 and 4 in Insig-2 in the luminal leaflet of the membrane. Unwinding of the middle of the Scap-S4 segment is crucial for 25HC binding and Insig association.
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Affiliation(s)
- Renhong Yan
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang Province, China
| | - Pingping Cao
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wenqi Song
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongwu Qian
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ximing Du
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW 2052, Australia
| | - Hudson W Coates
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW 2052, Australia
| | - Xin Zhao
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yaning Li
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shuai Gao
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Xin Gong
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Ximing Liu
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
| | - Jianhua Sui
- National Institute of Biological Sciences (NIBS), Beijing 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Jianlin Lei
- Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW 2052, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW 2052, Australia
| | - Qiang Zhou
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang Province, China
| | - Chuangye Yan
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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18
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Davis OB, Shin HR, Lim CY, Wu EY, Kukurugya M, Maher CF, Perera RM, Ordonez MP, Zoncu R. NPC1-mTORC1 Signaling Couples Cholesterol Sensing to Organelle Homeostasis and Is a Targetable Pathway in Niemann-Pick Type C. Dev Cell 2020; 56:260-276.e7. [PMID: 33308480 DOI: 10.1016/j.devcel.2020.11.016] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/05/2020] [Accepted: 11/17/2020] [Indexed: 01/22/2023]
Abstract
Lysosomes promote cellular homeostasis through macromolecular hydrolysis within their lumen and metabolic signaling by the mTORC1 kinase on their limiting membranes. Both hydrolytic and signaling functions require precise regulation of lysosomal cholesterol content. In Niemann-Pick type C (NPC), loss of the cholesterol exporter, NPC1, causes cholesterol accumulation within lysosomes, leading to mTORC1 hyperactivation, disrupted mitochondrial function, and neurodegeneration. The compositional and functional alterations in NPC lysosomes and nature of aberrant cholesterol-mTORC1 signaling contribution to organelle pathogenesis are not understood. Through proteomic profiling of NPC lysosomes, we find pronounced proteolytic impairment compounded with hydrolase depletion, enhanced membrane damage, and defective mitophagy. Genetic and pharmacologic mTORC1 inhibition restores lysosomal proteolysis without correcting cholesterol storage, implicating aberrant mTORC1 as a pathogenic driver downstream of cholesterol accumulation. Consistently, mTORC1 inhibition ameliorates mitochondrial dysfunction in a neuronal model of NPC. Thus, cholesterol-mTORC1 signaling controls organelle homeostasis and is a targetable pathway in NPC.
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Affiliation(s)
- Oliver B Davis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Hijai R Shin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Chun-Yan Lim
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Emma Y Wu
- Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037, USA; Department of Pediatric Gastroenterology, Hepatology, and Nutrition, University of California, San Diego, La Jolla, CA 92037, USA
| | - Matthew Kukurugya
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Claire F Maher
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Rushika M Perera
- Department of Anatomy and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - M Paulina Ordonez
- Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037, USA; Department of Pediatric Gastroenterology, Hepatology, and Nutrition, University of California, San Diego, La Jolla, CA 92037, USA.
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA.
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19
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Wangeline MA, Hampton RY. An autonomous, but INSIG-modulated, role for the sterol sensing domain in mallostery-regulated ERAD of yeast HMG-CoA reductase. J Biol Chem 2020; 296:100063. [PMID: 33184059 PMCID: PMC7948459 DOI: 10.1074/jbc.ra120.015910] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/01/2020] [Accepted: 11/12/2020] [Indexed: 01/23/2023] Open
Abstract
HMG-CoA reductase (HMGR) undergoes feedback-regulated degradation as part of sterol pathway control. Degradation of the yeast HMGR isozyme Hmg2 is controlled by the sterol pathway intermediate GGPP, which causes misfolding of Hmg2, leading to degradation by the HRD pathway; we call this process mallostery. We evaluated the role of the Hmg2 sterol sensing domain (SSD) in mallostery, as well as the involvement of the highly conserved INSIG proteins. We show that the Hmg2 SSD is critical for regulated degradation of Hmg2 and required for mallosteric misfolding of GGPP as studied by in vitro limited proteolysis. The Hmg2 SSD functions independently of conserved yeast INSIG proteins, but its function was modulated by INSIG, thus imposing a second layer of control on Hmg2 regulation. Mutant analyses indicated that SSD-mediated mallostery occurred prior to and independent of HRD-dependent ubiquitination. GGPP-dependent misfolding was still extant but occurred at a much slower rate in the absence of a functional SSD, indicating that the SSD facilitates a physiologically useful rate of GGPP response and implying that the SSD is not a binding site for GGPP. Nonfunctional SSD mutants allowed us to test the importance of Hmg2 quaternary structure in mallostery: a nonresponsive Hmg2 SSD mutant strongly suppressed regulation of a coexpressed, normal Hmg2. Finally, we have found that GGPP-regulated misfolding occurred in detergent-solubilized Hmg2, a feature that will allow next-level analysis of the mechanism of this novel tactic of ligand-regulated misfolding.
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Affiliation(s)
- Margaret A Wangeline
- Division of Biological Sciences, the Section of Cell and Developmental Biology, UCSD, La Jolla, California, USA
| | - Randolph Y Hampton
- Division of Biological Sciences, the Section of Cell and Developmental Biology, UCSD, La Jolla, California, USA.
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20
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Mechanisms and regulation of cholesterol homeostasis. Nat Rev Mol Cell Biol 2019; 21:225-245. [DOI: 10.1038/s41580-019-0190-7] [Citation(s) in RCA: 1094] [Impact Index Per Article: 182.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2019] [Indexed: 12/14/2022]
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21
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Oteng A, Loregger A, van Weeghel M, Zelcer N, Kersten S. Industrial Trans Fatty Acids Stimulate SREBP2-Mediated Cholesterogenesis and Promote Non-Alcoholic Fatty Liver Disease. Mol Nutr Food Res 2019; 63:e1900385. [PMID: 31327168 PMCID: PMC6790681 DOI: 10.1002/mnfr.201900385] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/01/2019] [Indexed: 12/24/2022]
Abstract
SCOPE The mechanisms underlying the deleterious effects of trans fatty acids on plasma cholesterol and non-alcoholic fatty liver disease (NAFLD) are unclear. Here, the aim is to investigate the molecular mechanisms of action of industrial trans fatty acids. METHODS AND RESULTS Hepa1-6 hepatoma cells were incubated with elaidate, oleate, or palmitate. C57Bl/6 mice were fed diets rich in trans-unsaturated, cis-unsaturated, or saturated fatty acids. Transcriptomics analysis of Hepa1-6 cells shows that elaidate but not oleate or palmitate induces expression of genes involved in cholesterol biosynthesis. Induction of cholesterogenesis by elaidate is mediated by increased sterol regulatory element-binding protein 2 (SREBP2) activity and is dependent on SREBP cleavage-activating protein (SCAP), yet independent of liver-X receptor and ubiquitin regulatory X domain-containing protein 8. Elaidate decreases intracellular free cholesterol levels and represses the anticholesterogenic effect of exogenous cholesterol. In mice, the trans-unsaturated diet increases the ratio of liver to gonadal fat mass, steatosis, hepatic cholesterol levels, alanine aminotransferase activity, and fibrosis markers, suggesting enhanced NAFLD, compared to the cis-unsaturated and saturated diets. CONCLUSION Elaidate induces cholesterogenesis in vitro by activating the SCAP-SREBP2 axis, likely by lowering intracellular free cholesterol and attenuating cholesterol-dependent repression of SCAP. This pathway potentially underlies the increase in liver cholesterol and NAFLD by industrial trans fatty acids.
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Affiliation(s)
- Antwi‐Boasiako Oteng
- Nutrition, Metabolism and Genomics GroupDivision of Human Nutrition and HealthWageningen University6708 WEWageningenThe Netherlands
| | - Anke Loregger
- Department of Medical BiochemistryAcademic Medical CenterUniversity of Amsterdam1105 AZAmsterdamThe Netherlands
| | - Michel van Weeghel
- Laboratory Genetic Metabolic DiseasesAmsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences1105 AZAmsterdamThe Netherlands
| | - Noam Zelcer
- Department of Medical BiochemistryAcademic Medical CenterUniversity of Amsterdam1105 AZAmsterdamThe Netherlands
| | - Sander Kersten
- Nutrition, Metabolism and Genomics GroupDivision of Human Nutrition and HealthWageningen University6708 WEWageningenThe Netherlands
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22
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Chen L, Ma MY, Sun M, Jiang LY, Zhao XT, Fang XX, Man Lam S, Shui GH, Luo J, Shi XJ, Song BL. Endogenous sterol intermediates of the mevalonate pathway regulate HMGCR degradation and SREBP-2 processing. J Lipid Res 2019; 60:1765-1775. [PMID: 31455613 DOI: 10.1194/jlr.ra119000201] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/21/2019] [Indexed: 11/20/2022] Open
Abstract
Sterol-regulated HMG-CoA reductase (HMGCR) degradation and SREBP-2 cleavage are two major feedback regulatory mechanisms governing cholesterol biosynthesis. Reportedly, lanosterol selectively stimulates HMGCR degradation, and cholesterol is a specific regulator of SREBP-2 cleavage. However, it is unclear whether other endogenously generated sterols regulate these events. Here, we investigated the sterol intermediates from the mevalonate pathway of cholesterol biosynthesis using a CRISPR/Cas9-mediated genetic engineering approach. With a constructed HeLa cell line expressing the mevalonate transporter, we individually deleted genes encoding major enzymes in the mevalonate pathway, used lipidomics to measure sterol intermediates, and examined HMGCR and SREBP-2 statuses. We found that the C4-dimethylated sterol intermediates, including lanosterol, 24,25-dihydrolanosterol, follicular fluid meiosis activating sterol, testis meiosis activating sterol, and dihydro-testis meiosis activating sterol, were significantly upregulated upon mevalonate loading. These intermediates augmented both degradation of HMGCR and inhibition of SREBP-2 cleavage. The accumulated lanosterol induced rapid degradation of HMGCR, but did not inhibit SREBP-2 cleavage. The newly synthesized cholesterol from the mevalonate pathway is dispensable for inhibiting SREBP-2 cleavage. Together, these results suggest that lanosterol is a bona fide endogenous regulator that specifically promotes HMGCR degradation, and that other C4-dimethylated sterol intermediates may regulate both HMGCR degradation and SREBP-2 cleavage.
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Affiliation(s)
- Liang Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Mei-Yan Ma
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ming Sun
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Lu-Yi Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xue-Tong Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xian-Xiu Fang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology , Chinese Academy of Sciences, Beijing 100101, China
| | - Guang-Hou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology , Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiong-Jie Shi
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
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23
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Fantini J, Epand RM, Barrantes FJ. Cholesterol-Recognition Motifs in Membrane Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1135:3-25. [PMID: 31098808 DOI: 10.1007/978-3-030-14265-0_1] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The impact of cholesterol on the structure and function of membrane proteins was recognized several decades ago, but the molecular mechanisms underlying these effects have remained elusive. There appear to be multiple mechanisms by which cholesterol interacts with proteins. A complete understanding of cholesterol-sensing motifs is still undergoing refinement. Initially, cholesterol was thought to exert only non-specific effects on membrane fluidity. It was later shown that this lipid could specifically interact with membrane proteins and affect both their structure and function. In this article, we have summarized and critically analyzed our evolving understanding of the affinity, specificity and stereoselectivity of the interactions of cholesterol with membrane proteins. We review the different computational approaches that are currently used to identify cholesterol binding sites in membrane proteins and the biochemical logic that governs each type of site, including CRAC, CARC, SSD and amphipathic helix motifs. There are physiological implications of these cholesterol-recognition motifs for G-protein coupled receptors (GPCR) and ion channels, in membrane trafficking and membrane fusion (SNARE) proteins. There are also pathological implications of cholesterol binding to proteins involved in neurological disorders (Alzheimer, Parkinson, Creutzfeldt-Jakob) and HIV fusion. In each case, our discussion is focused on the key molecular aspects of the cholesterol and amino acid motifs in membrane-embedded regions of membrane proteins that define the physiologically relevant crosstalk between the two. Our understanding of the factors that determine if these motifs are functional in cholesterol binding will allow us enhanced predictive capabilities.
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Affiliation(s)
- Jacques Fantini
- INSERM UMR_S 1072, Marseille, France. .,Aix-Marseille Université, Marseille, France.
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Health Sciences Centre, Hamilton, ON, Canada
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute (BIOMED), UCA-CONICET, Buenos Aires, Argentina
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24
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Ma S, Sun W, Gao L, Liu S. Therapeutic targets of hypercholesterolemia: HMGCR and LDLR. Diabetes Metab Syndr Obes 2019; 12:1543-1553. [PMID: 31686875 PMCID: PMC6709517 DOI: 10.2147/dmso.s219013] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 07/25/2019] [Indexed: 12/14/2022] Open
Abstract
Cholesterol homeostasis is critical and necessary for the body's functions. Hypercholesterolemia can lead to significant clinical problems, such as cardiovascular disease (CVD). 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and low-density lipoprotein cholesterol receptor (LDLR) are major points of control in cholesterol homeostasis. We summarize the regulatory mechanisms of HMGCR and LDLR, which may provide insight for new drug design and development.
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Affiliation(s)
- Shizhan Ma
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan250021, People’s Republic of China
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan250021, People’s Republic of China
| | - Wenxiu Sun
- Department of Pharmacy, Taishan Vocational College of Nursing, Taian271000, People’s Republic of China
| | - Ling Gao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan250021, People’s Republic of China
- Scientific Center, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan250021, People’s Republic of China
- Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan250021, People’s Republic of China
- Correspondence: Ling GaoScientific Center, Shandong Provincial Hospital Affiliated to Shandong University, 324 Jing 5 Road, Jinan, Shandong Province250021, People’s Republic of ChinaTel +86 531 6877 6910Email
| | - Shudong Liu
- Department of Endocrinology, Shandong Rongjun General Hospital, Jinan250013, People’s Republic of China
- Shudong LiuDepartment of Endocrinology, Shandong Rongjun General Hospital, 23 Jiefang Road, Jinan, Shandong Province250013, People’s Republic of ChinaTel +86 531 8238 2351Email
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25
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Benito-Vicente A, Uribe KB, Jebari S, Galicia-Garcia U, Ostolaza H, Martin C. Familial Hypercholesterolemia: The Most Frequent Cholesterol Metabolism Disorder Caused Disease. Int J Mol Sci 2018; 19:ijms19113426. [PMID: 30388787 PMCID: PMC6275065 DOI: 10.3390/ijms19113426] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 10/21/2018] [Accepted: 10/29/2018] [Indexed: 12/18/2022] Open
Abstract
Cholesterol is an essential component of cell barrier formation and signaling transduction involved in many essential physiologic processes. For this reason, cholesterol metabolism must be tightly controlled. Cell cholesterol is mainly acquired from two sources: Dietary cholesterol, which is absorbed in the intestine and, intracellularly synthesized cholesterol that is mainly synthesized in the liver. Once acquired, both are delivered to peripheral tissues in a lipoprotein dependent mechanism. Malfunctioning of cholesterol metabolism is caused by multiple hereditary diseases, including Familial Hypercholesterolemia, Sitosterolemia Type C and Niemann-Pick Type C1. Of these, familial hypercholesterolemia (FH) is a common inherited autosomal co-dominant disorder characterized by high plasma cholesterol levels. Its frequency is estimated to be 1:200 and, if untreated, increases the risk of premature cardiovascular disease. This review aims to summarize the current knowledge on cholesterol metabolism and the relation of FH to cholesterol homeostasis with special focus on the genetics, diagnosis and treatment.
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Affiliation(s)
- Asier Benito-Vicente
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Shifa Jebari
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Unai Galicia-Garcia
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Helena Ostolaza
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Cesar Martin
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
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26
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Binot C, Sadoc JF, Chouard CH. Oncogenesis, lipids rafts and liquid crystals: A nanoscopic supplementary field for applied researches and a new hope of advances in cancer. Heliyon 2018; 4:e00687. [PMID: 30035237 PMCID: PMC6051303 DOI: 10.1016/j.heliyon.2018.e00687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 12/14/2022] Open
Abstract
Liquid crystals (LC) are an intermediate state between an ordered crystalline solid and a more disordered liquid. LCs (or mesophases) are ubiquitous in living systems, optimizing multiple biological functions that could not operate in purely solid or liquid environments as both mobility and organization are needed. One of us recently suggested that there is an information vector, shared by neurodegenerative and infectious pathologies, to be found within lipid rafts in an ordered liquid (Lo) form mediated by cholesterol. Here we extend this underlying mechanism to oncogenic processes. The specificity of our approach lies in highlighting the direct involvement of liquid crystals in early carcinogenic processes, by identifying specific metabolic pathways, with the intention of focusing research effort on this level, now that this has become technically feasible. Exploring LCs in living bodies reveals links between numerous oncogenic mechanisms. The approach is based on the geometric properties of amphiphilic (hydrophilic and lipophilic) plasma and intracellular membranes, the phospholipids of which are an example of the lamellar LC phase. These LCs underlie cell signaling and signaling pathways disorders at membrane level: consequently, they are directly concerned with deregulation underlying many cancerous processes. We demonstrate the implication of cancer cell membranes mesophases. That is in the membranes mesophases that are initiated most of metabolic pathways, leading to downstream pathogenic intracellular mechanisms. The concepts of order and of symmetry, in the mathematical sense, involved in condensed matter accompany informed adaptive supramolecular chemical processes in forming self-organizing mesogenic molecular assemblies. Multidisciplinary teamwork combining knowledge from different fields holds out the hope of therapeutic progress upstream of irreversible cancerous processes, while conserving the physiological integrity of the cells themselves.
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27
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Dutta B, Bhattacharjee B, Chowdhury J. Physics behind the Barrier to Internal Rotation of an Acetyl Chloride Molecule: A Combined Approach from Density Functional Theory, Car-Parrinello Molecular Dynamics, and Time-Resolved Wavelet Transform Theory. ACS OMEGA 2018; 3:6794-6803. [PMID: 31458850 PMCID: PMC6644580 DOI: 10.1021/acsomega.8b00316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/18/2018] [Indexed: 06/10/2023]
Abstract
The physics behind the barriers to internal rotation of acetyl chloride (AC) molecule has been reported. The AC molecule closely resembles the molecular structure of acetaldehyde; the only subtle difference is the presence of a heavy chlorine atom in place of the hydrogen atom of the aldehyde group for the latter. This paper aims to study the effect of substitution of the heavy chlorine atom on the barrier energetics of the AC molecule. The reason behind the barrier for the AC molecule has been estimated for the first time from the unified approach using barrier energetics, natural bond orbital, nuclear virial, and relaxation analyses using density functional theory, Car-Parrinello molecular dynamics, and wavelet transform theory. Complete analyses reveal the concomitant relaxations of both the in-plane Cmethyl-C1 and Cmethyl-H4 bonds toward understanding the origin of the barrier due to internal rotation for the AC molecule. The large negative value of "V 6" further suggests that both the abovementioned degrees of freedom are coupled with the -CH3 torsional vibration of the molecule. The coupling matrix (H 12) element has also been estimated. Time-resolved band stretching frequencies of Cmethyl-C1 and C1-Cl3 bonds of the AC molecule, as obtained from wavelet transformation analysis, primarily preclude the possibility of coupling between the C1-Cl3 bond and the torsional motion associated with the methyl group of the molecule.
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Affiliation(s)
- Bipan Dutta
- Department
of Physics, Sammilani Mahavidyalaya, E. M. Bypass, Baghajatin Station, Kolkata 700094, India
| | - Biplab Bhattacharjee
- Department of Chemistry and Department of Physics, Jadavpur University, 88, Raja S. C. Mallick Road, Kolkata 700032, India
| | - Joydeep Chowdhury
- Department of Chemistry and Department of Physics, Jadavpur University, 88, Raja S. C. Mallick Road, Kolkata 700032, India
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28
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Cheng C, Geng F, Cheng X, Guo D. Lipid metabolism reprogramming and its potential targets in cancer. Cancer Commun (Lond) 2018; 38:27. [PMID: 29784041 PMCID: PMC5993136 DOI: 10.1186/s40880-018-0301-4] [Citation(s) in RCA: 526] [Impact Index Per Article: 75.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/12/2018] [Indexed: 12/13/2022] Open
Abstract
Reprogramming of lipid metabolism is a newly recognized hallmark of malignancy. Increased lipid uptake, storage and lipogenesis occur in a variety of cancers and contribute to rapid tumor growth. Lipids constitute the basic structure of membranes and also function as signaling molecules and energy sources. Sterol regulatory element-binding proteins (SREBPs), a family of membrane-bound transcription factors in the endoplasmic reticulum, play a central role in the regulation of lipid metabolism. Recent studies have revealed that SREBPs are highly up-regulated in various cancers and promote tumor growth. SREBP cleavage-activating protein is a key transporter in the trafficking and activation of SREBPs as well as a critical glucose sensor, thus linking glucose metabolism and de novo lipid synthesis. Targeting altered lipid metabolic pathways has become a promising anti-cancer strategy. This review summarizes recent progress in our understanding of lipid metabolism regulation in malignancy, and highlights potential molecular targets and their inhibitors for cancer treatment.
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Affiliation(s)
- Chunming Cheng
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Columbus, OH, 43210, USA
| | - Feng Geng
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Columbus, OH, 43210, USA
| | - Xiang Cheng
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Columbus, OH, 43210, USA
| | - Deliang Guo
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Columbus, OH, 43210, USA.
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29
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DeBose-Boyd RA, Ye J. SREBPs in Lipid Metabolism, Insulin Signaling, and Beyond. Trends Biochem Sci 2018; 43:358-368. [PMID: 29500098 DOI: 10.1016/j.tibs.2018.01.005] [Citation(s) in RCA: 232] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/08/2018] [Accepted: 01/10/2018] [Indexed: 12/22/2022]
Abstract
Sterol regulatory element-binding proteins (SREBPs) are a family of membrane-bound transcription factors that activate genes encoding enzymes required for synthesis of cholesterol and unsaturated fatty acids. SREBPs are controlled by multiple mechanisms at the level of mRNA synthesis, proteolytic activation, and transcriptional activity. In this review, we summarize the recent findings that contribute to the current understanding of the regulation of SREBPs and their physiologic roles in maintenance of lipid homeostasis, insulin signaling, innate immunity, and cancer development.
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Affiliation(s)
- Russell A DeBose-Boyd
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9046, USA.
| | - Jin Ye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9046, USA.
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30
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Abstract
PURPOSE OF REVIEW High-density lipoproteins (HDL) are thought to exert a protective role against atherosclerosis. The measurement of the cholesterol mass within HDL (HDL-C) represents a good biomarker of cardiovascular health, but HDL-C appears to be a poor therapeutic target. Here, we discuss new targets for the development of HDL-directed therapies. RECENT FINDINGS Among cardio-protective functions of HDL particles, the ability of HDL to remove cholesterol from cells involved in the early stages of atherosclerosis is considered one of the most important functions. This process, termed "HDL biogenesis," is initiated by the formation of highly specialized plasma membrane micro-domains by the ATP-binding cassette transporter A1 (ABCA1) and the binding of apolipoproteins (apo) such as apoA-I, the major protein moiety of HDL, to the micro-domains. Although early strategies aimed at increasing HDL biogenesis by upregulating ABCA1 or apoA-I gene expression have not met with clinical success, recent advances in understanding transcriptional, post-transcriptional, and post-translational regulatory pathways propose new targets for the promotion of HDL biogenesis. We have recently reported that a novel apoA-I-binding protein desmocollin 1 (DSC1) prevents HDL biogenesis and that inhibition of apoA-I-DSC1 interactions promotes HDL biogenesis by stabilizing ABCA1. This new HDL regulation pathway nominates DSC1 as an attractive pharmacological target. In the absence of clinically useful therapy to increase HDL biogenesis, finding novel targets to unlock the therapeutic potential of HDL is highly desired. Modulation of apoA-I-DSC1 interactions may be a viable strategy.
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Affiliation(s)
- Jacques Genest
- The Research Institute of the McGill University Health Center, 1001 boul. Decarie Bloc E, Office EM12212, Montreal, Québec, H4A 3J1, Canada
| | - Hong Y Choi
- The Research Institute of the McGill University Health Center, 1001 boul. Decarie Bloc E, Office EM12212, Montreal, Québec, H4A 3J1, Canada.
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31
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Jacquemyn J, Cascalho A, Goodchild RE. The ins and outs of endoplasmic reticulum-controlled lipid biosynthesis. EMBO Rep 2017; 18:1905-1921. [PMID: 29074503 DOI: 10.15252/embr.201643426] [Citation(s) in RCA: 189] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 08/18/2017] [Accepted: 09/18/2017] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER)-localized enzymes synthesize the vast majority of cellular lipids. The ER therefore has a major influence on cellular lipid biomass and balances the production of different lipid categories, classes, and species. Signals from outside and inside the cell are directed to ER-localized enzymes, and lipid enzyme activities are defined by the integration of internal, homeostatic, and external information. This allows ER-localized lipid synthesis to provide the cell with membrane lipids for growth, proliferation, and differentiation-based changes in morphology and structure, and to maintain membrane homeostasis across the cell. ER enzymes also respond to physiological signals to drive carbohydrates and nutritionally derived lipids into energy-storing triglycerides. In this review, we highlight some key regulatory mechanisms that control ER-localized enzyme activities in animal cells. We also discuss how they act in concert to maintain cellular lipid homeostasis, as well as how their dysregulation contributes to human disease.
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Affiliation(s)
- Julie Jacquemyn
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ana Cascalho
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Rose E Goodchild
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium .,Department of Neurosciences, KU Leuven, Leuven, Belgium
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32
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Brown MS, Radhakrishnan A, Goldstein JL. Retrospective on Cholesterol Homeostasis: The Central Role of Scap. Annu Rev Biochem 2017; 87:783-807. [PMID: 28841344 DOI: 10.1146/annurev-biochem-062917-011852] [Citation(s) in RCA: 355] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Scap is a polytopic membrane protein that functions as a molecular machine to control the cholesterol content of membranes in mammalian cells. In the 21 years since our laboratory discovered Scap, we have learned how it binds sterol regulatory element-binding proteins (SREBPs) and transports them from the endoplasmic reticulum (ER) to the Golgi for proteolytic processing. Proteolysis releases the SREBP transcription factor domains, which enter the nucleus to promote cholesterol synthesis and uptake. When cholesterol in ER membranes exceeds a threshold, the sterol binds to Scap, triggering several conformational changes that prevent the Scap-SREBP complex from leaving the ER. As a result, SREBPs are no longer processed, cholesterol synthesis and uptake are repressed, and cholesterol homeostasis is restored. This review focuses on the four domains of Scap that undergo concerted conformational changes in response to cholesterol binding. The data provide a molecular mechanism for the control of lipids in cell membranes.
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Affiliation(s)
- Michael S Brown
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; ;
| | - Arun Radhakrishnan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; ;
| | - Joseph L Goldstein
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; ;
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