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Haaker MW, Goossens V, Hoogland NAN, van Doorne H, Wang Z, Jansen JWA, Kaloyanova DV, van de Lest CHA, Houweling M, Vaandrager AB, Helms JB. Early activation of hepatic stellate cells induces rapid initiation of retinyl ester breakdown while maintaining lecithin:retinol acyltransferase (LRAT) activity. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159540. [PMID: 39068984 DOI: 10.1016/j.bbalip.2024.159540] [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: 12/21/2023] [Revised: 06/30/2024] [Accepted: 07/25/2024] [Indexed: 07/30/2024]
Abstract
Lecithin:retinol acyltransferase (LRAT) is the main enzyme producing retinyl esters (REs) in quiescent hepatic stellate cells (HSCs). When cultured on stiff plastic culture plates, quiescent HSCs activate and lose their RE stores in a process similar to that in the liver following tissue damage, leading to fibrosis. Here we validated HSC cultures in soft gels to study RE metabolism in stable quiescent HSCs and investigated RE synthesis and breakdown in activating HSCs. HSCs cultured in a soft gel maintained characteristics of quiescent HSCs, including the size, amount and composition of their characteristic large lipid droplets. Quiescent gel-cultured HSCs maintained high expression levels of Lrat and a RE storing phenotype with low levels of RE breakdown. Newly formed REs are highly enriched in retinyl palmitate (RP), similar to freshly isolated quiescent HSCs, which is associated with high LRAT activity. Comparison of these quiescent gel-cultured HSCs with activated plastic-cultured HSCs showed that although during early activation the total RE levels and RP-enrichment are reduced, levels of RE formation are maintained and mediated by LRAT. Loss of REs was caused by enhanced RE breakdown in activating HSCs. Upon prolonged culturing, activated HSCs have lost their LRAT activity and produce small amounts of REs by DGAT1. This study reveals unexpected dynamics in RE metabolism during early HSC activation, which might be important in liver disease as early stages are reversible. Soft gel cultures provide a promising model to study RE metabolism in quiescent HSCs, allowing detailed molecular investigations on the mechanisms for storage and release.
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Affiliation(s)
- Maya W Haaker
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Vera Goossens
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Nina A N Hoogland
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Hidde van Doorne
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Ziqiong Wang
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Jeroen W A Jansen
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Dora V Kaloyanova
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Chris H A van de Lest
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Martin Houweling
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - A Bas Vaandrager
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - J Bernd Helms
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism & Cancer, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, the Netherlands.
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2
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Muturi HT, Ghadieh HE, Asalla S, Lester SG, Verhulst S, Stankus HL, Zaidi S, Abdolahipour R, Belew GD, van Grunsven LA, Friedman SL, Schwabe RF, Hinds TD, Najjar SM. Conditional deletion of CEACAM1 causes hepatic stellate cell activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.586238. [PMID: 38617330 PMCID: PMC11014538 DOI: 10.1101/2024.04.02.586238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Objectives Hepatic CEACAM1 expression declines with advanced hepatic fibrosis stage in patients with MASH. Global and hepatocyte-specific deletions of Ceacam1 impair insulin clearance to cause hepatic insulin resistance and steatosis. They also cause hepatic inflammation and fibrosis, a condition characterized by excessive collagen production from activated hepatic stellate cells (HSCs). Given the positive effect of PPARγ on CEACAM1 transcriptoin and on HSCs quiescence, the current studies investigated whether CEACAM1 loss from HSCs causes their activation. Methods We examined whether lentiviral shRNA-mediated CEACAM1 donwregulation (KD-LX2) activates cultured human LX2 stellate cells. We also generated LratCre+Cc1 fl/fl mutants with conditional Ceacam1 deletion in HSCs and characterized their MASH phenotype. Media transfer experiments were employed to examine whether media from mutant human and murine HSCs activate their wild-type counterparts. Results LratCre+Cc1 fl/fl mutants displayed hepatic inflammation and fibrosis but without insulin resistance or hepatic steatosis. Their HSCs, like KD-LX2 cells, underwent myofibroblastic transformation and their media activated wild-type HDCs. This was inhibited by nicotinic acid treatment which stemmed the release of IL-6 and fatty acids, both of which activate the epidermal growth factor receptor (EGFR) tyrosine kinase. Gefitinib inhibition of EGFR and its downstream NF-κB/IL-6/STAT3 inflammatory and MAPK-proliferation pathways also blunted HSCs activation in the absence of CEACAM1. Conclusions Loss of CEACAM1 in HSCs provoked their myofibroblastic transformation in the absence of insulin resistance and hepatic steatosis. This response is mediated by autocrine HSCs activation of the EGFR pathway that amplifies inflammation and proliferation.
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Ding K, Liu C, Li L, Yang M, Jiang N, Luo S, Sun L. Acyl-CoA synthase ACSL4: an essential target in ferroptosis and fatty acid metabolism. Chin Med J (Engl) 2023; 136:2521-2537. [PMID: 37442770 PMCID: PMC10617883 DOI: 10.1097/cm9.0000000000002533] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Indexed: 07/15/2023] Open
Abstract
ABSTRACT Long-chain acyl-coenzyme A (CoA) synthase 4 (ACSL4) is an enzyme that esterifies CoA into specific polyunsaturated fatty acids, such as arachidonic acid and adrenic acid. Based on accumulated evidence, the ACSL4-catalyzed biosynthesis of arachidonoyl-CoA contributes to the execution of ferroptosis by triggering phospholipid peroxidation. Ferroptosis is a type of programmed cell death caused by iron-dependent peroxidation of lipids; ACSL4 and glutathione peroxidase 4 positively and negatively regulate ferroptosis, respectively. In addition, ACSL4 is an essential regulator of fatty acid (FA) metabolism. ACSL4 remodels the phospholipid composition of cell membranes, regulates steroidogenesis, and balances eicosanoid biosynthesis. In addition, ACSL4-mediated metabolic reprogramming and antitumor immunity have attracted much attention in cancer biology. Because it facilitates the cross-talk between ferroptosis and FA metabolism, ACSL4 is also a research hotspot in metabolic diseases and ischemia/reperfusion injuries. In this review, we focus on the structure, biological function, and unique role of ASCL4 in various human diseases. Finally, we propose that ACSL4 might be a potential therapeutic target.
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Affiliation(s)
- Kaiyue Ding
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
| | - Chongbin Liu
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
| | - Li Li
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
| | - Ming Yang
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
| | - Na Jiang
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
| | - Shilu Luo
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
| | - Lin Sun
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Changsha, Hunan 410000, China
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Hammoudeh N, Soukkarieh C, Murphy DJ, Hanano A. Mammalian lipid droplets: structural, pathological, immunological and anti-toxicological roles. Prog Lipid Res 2023; 91:101233. [PMID: 37156444 DOI: 10.1016/j.plipres.2023.101233] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/30/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023]
Abstract
Mammalian lipid droplets (LDs) are specialized cytosolic organelles consisting of a neutral lipid core surrounded by a membrane made up of a phospholipid monolayer and a specific population of proteins that varies according to the location and function of each LD. Over the past decade, there have been significant advances in the understanding of LD biogenesis and functions. LDs are now recognized as dynamic organelles that participate in many aspects of cellular homeostasis plus other vital functions. LD biogenesis is a complex, highly-regulated process with assembly occurring on the endoplasmic reticulum although aspects of the underpinning molecular mechanisms remain elusive. For example, it is unclear how many enzymes participate in the biosynthesis of the neutral lipid components of LDs and how this process is coordinated in response to different metabolic cues to promote or suppress LD formation and turnover. In addition to enzymes involved in the biosynthesis of neutral lipids, various scaffolding proteins play roles in coordinating LD formation. Despite their lack of ultrastructural diversity, LDs in different mammalian cell types are involved in a wide range of biological functions. These include roles in membrane homeostasis, regulation of hypoxia, neoplastic inflammatory responses, cellular oxidative status, lipid peroxidation, and protection against potentially toxic intracellular fatty acids and lipophilic xenobiotics. Herein, the roles of mammalian LDs and their associated proteins are reviewed with a particular focus on their roles in pathological, immunological and anti-toxicological processes.
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Affiliation(s)
- Nour Hammoudeh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Chadi Soukkarieh
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Denis J Murphy
- School of Applied Sciences, University of South Wales, Pontypridd, CF37 1DL, Wales, United Kingdom..
| | - Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria..
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5
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Molenaar MR, Haaker MW, Vaandrager AB, Houweling M, Helms JB. Lipidomic profiling of rat hepatic stellate cells during activation reveals a two-stage process accompanied by increased levels of lysosomal lipids. J Biol Chem 2023; 299:103042. [PMID: 36803964 PMCID: PMC10033282 DOI: 10.1016/j.jbc.2023.103042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 01/30/2023] [Accepted: 02/07/2023] [Indexed: 02/19/2023] Open
Abstract
Hepatic stellate cells (HSCs) are liver-resident cells best known for their role in vitamin A storage under physiological conditions. Upon liver injury, HSCs activate into myofibroblast-like cells, a key process in the onset of liver fibrosis. Lipids play an important role during HSC activation. Here, we provide a comprehensive characterization of the lipidomes of primary rat HSCs during 17 days of activation in vitro. For lipidomic data interpretation, we expanded our previously described Lipid Ontology (LION) and associated web application (LION/Web) with the LION-PCA heatmap module, which generates heatmaps of the most typical LION-signatures in lipidomic datasets. Furthermore, we used LION to perform pathway analysis to determine the significant metabolic conversions in lipid pathways. Together, we identify two distinct stages of HSC activation. In the first stage, we observe a decrease of saturated phosphatidylcholine, sphingomyelin, and phosphatidic acid and an increase in phosphatidylserine and polyunsaturated bis(monoacylglycero)phosphate (BMP), a lipid class typically localized at endosomes and lysosomes. In the second activation stage, BMPs, hexosylceramides, and ether-linked phosphatidylcholines are elevated, resembling a lysosomal lipid storage disease profile. The presence of isomeric structures of BMP in HSCs was confirmed ex vivo in MS-imaging datasets of steatosed liver sections. Finally, treatment with pharmaceuticals targeting the lysosomal integrity led to cell death in primary HSCs but not in HeLa cells. In summary, our combined data suggest that lysosomes play a critical role during a two-stage activation process of HSCs.
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Affiliation(s)
- Martijn R Molenaar
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Maya W Haaker
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - A Bas Vaandrager
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Martin Houweling
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - J Bernd Helms
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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6
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Mak KM, Wu C, Cheng CP. Lipid droplets, the Holy Grail of hepatic stellate cells: In health and hepatic fibrosis. Anat Rec (Hoboken) 2022; 306:983-1010. [PMID: 36516055 DOI: 10.1002/ar.25138] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/07/2022] [Accepted: 11/29/2022] [Indexed: 12/15/2022]
Abstract
Lipid droplets (LDs) are distinct morphological markers of hepatic stellate cells (HSCs). They are composed of a core of predominantly retinyl esters and triacylglycerols surrounded by a phospholipid layer; the latter harbors perilipins 2, 3, and 5, which help control LD lipolysis. Electron microscopy distinguishes between Types I and II LDs. Type I LDs are surrounded by acid phosphatase-positive lysosomes, which likely digest LDs. LD count and retinoid concentration are modulated by vitamin A intake. Alcohol consumption depletes hepatic retinoids and HSC LDs, with concomitant transformation of HSCs to fibrogenic myofibroblast-like cells. LD loss and accompanying HSC activation occur in HSC cell culture models. Loss of LDs is a consequence of and not a prerequisite for HSC activation. LDs are endowed with enzymes for synthesizing retinyl esters and triacylglycerols as well as neutral lipases and lysosomal acid lipase for breaking down LDs. HSCs have two distinct metabolic LD pools: an "original" pool in quiescent HSCs and a "new" pool emerging in HSC activation; this two-pool model provides a platform for analyzing LD dynamics in HSC activation. Besides lipolysis, LDs are degraded by lipophagy; however, the coordination between and relative contributions of these two pathways to LD removal are unclear. While induction of autophagy accelerates LD loss in quiescent HSCs and promotes HSC activation, blocking autophagy impairs LD degradation and inhibits HSC activation and fibrosis. This article is a critique of five decades of investigations into the morphology, molecular structure, synthesis, and degradation of LDs associated with HSC activation and fibrosis.
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Affiliation(s)
- Ki M Mak
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Catherine Wu
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Christopher P Cheng
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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7
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Bioinformatics Analysis of Common Genetic and Molecular Traits and Association of Portal Hypertension with Pulmonary Hypertension. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:9237701. [PMID: 36312597 PMCID: PMC9613398 DOI: 10.1155/2022/9237701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/19/2022] [Accepted: 09/28/2022] [Indexed: 12/16/2022]
Abstract
Portal hypertension (PH) is an important cause of pulmonary arterial hypertension(PAH), but its mechanism is still unclear. We used genetic data analysis to explore the shared genes and molecular mechanisms of PH and PAH. We downloaded the PH and PAH data from the GEO database, and used the weighted gene coexpression network analysis method (WGCNA) to analyze the coexpression modules of idiopathic noncirrhotic portal hypertension (INCPH) and cirrhotic portal hypertension (CPH) and pulmonary hypertension, respectively. Enrichment analysis was performed on the common genes, and differential gene expressions (DEGs) were used for verification. The target genes of INCPH and PAH were obtained by string and cytoscape software, and the miRNAs of target genes were predicted by miRwalk, miRDB, and TargetScan and their biological functions were analyzed; finally, we used PanglaoDB to predict the expression of target genes in cells. In WGCNA, gene modules significantly related to PAH, CPH, and INCPH were identified, and enrichment function analysis showed that the common pathway of PAH and CPH were “P53 signaling pathway,” “synthesis of neutral lipids”; PAH and INCPH are “terminal,” “Maintenance Regulation of Granules,” and “Toxin Transport.” DEGs confirmed the results of WGCNA; the common miRNA functions of PAH and cirrhosis were enriched for “P53 signaling pathway,” “TGF-β signaling pathway,” “TNF signaling pathway,” and “fatty acid metabolism,” and the miRNAs-mRNAs network suggested that hsa-miR-22a-3p regulates MDM2 and hsa-miR-34a-5p regulates PRDX4; the target genes of PAH and INCPH are EIF5B, HSPA4, GNL3, RARS, UTP20, HNRNPA2B1, HSP90B1, METAP2, NARS, SACM1L, and their target miRNA function enrichment showed EIF5B, HNRNPA2B1, HSP90B1, METAP2, NARS, SACM1L, and HSPA4 are associated with telomeres and inflammation, panglaoDB showed that target genes are located in endothelial cells, smooth muscle cells, etc. In conclusion, the mechanism of pulmonary hypertension induced by portal hypertension may be related to telomere dysfunction and P53 overactivation, and lipid metabolism and intestinal inflammation are also involved in this process.
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Duan J, Wang Z, Duan R, Yang C, Zhao R, Feng Q, Qin Y, Jiang J, Gu S, Lv K, zhang L, He B, Birnbaumer L, Yang S, Chen Z, Yang Y. Therapeutic targeting of hepatic ACSL4 ameliorates NASH in mice. Hepatology 2022; 75:140-153. [PMID: 34510514 PMCID: PMC8688219 DOI: 10.1002/hep.32148] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/11/2021] [Accepted: 09/03/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND AND AIMS Globally, NAFLD is one of the most common liver disorders, with an estimated prevalence rate of more than 30% in men and 15% in women and an even higher prevalence in people with type 2 diabetes mellitus. Optimal pharmacologic therapeutic approaches for NAFLD are an urgent necessity. APPROACH AND RESULTS In this study, we showed that compared with healthy controls, hepatic ACSL4 levels in patients with NAFLD were found to be elevated. Suppression of ACSL4 expression promoted mitochondrial respiration, thereby enhancing the capacity of hepatocytes to mediate β-oxidation of fatty acids and to minimize lipid accumulation by up-regulating peroxisome proliferator-activated receptor coactivator-1 alpha. Moreover, we found that abemaciclib is a potent and selective ACSL4 inhibitor, and low dose of abemaciclib significantly ameliorated most of the NAFLD symptoms in multiple NAFLD mice models. CONCLUSIONS Therefore, inhibition of ACSL4 is a potential alternative therapeutic approach for NAFLD.
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Affiliation(s)
- Jingjing Duan
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Zhuo Wang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Ran Duan
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Chenxinhui Yang
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Ruolin Zhao
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Qi Feng
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Yuanyuan Qin
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Jingwei Jiang
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Shouyong Gu
- Province Geriatic Hospital, 30 Luojia Road, Nanjing 210024, China
| | - Kaiyan Lv
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Libo zhang
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Bixia He
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Lutz Birnbaumer
- Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires C1107AFF, Argentina, and Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | - Song Yang
- Center of hepatology, Beijing Ditan Hospital of Capital Medical University, Beijing 100015, China
| | - Zhen Chen
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
| | - Yong Yang
- Center for New Drug Safety Evaluation and Research, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China
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Yang Y, Zeng QS, Zou M, Zeng J, Nie J, Chen D, Gan HT. Targeting Gremlin 1 Prevents Intestinal Fibrosis Progression by Inhibiting the Fatty Acid Oxidation of Fibroblast Cells. Front Pharmacol 2021; 12:663774. [PMID: 33967807 PMCID: PMC8100665 DOI: 10.3389/fphar.2021.663774] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/08/2021] [Indexed: 02/05/2023] Open
Abstract
Intestinal fibrosis is a consequence of continuous inflammatory responses that negatively affect the quality of life of patients. By screening altered proteomic profiles of mouse fibrotic colon tissues, we identified that GREM1 was dramatically upregulated in comparison to that in normal tissues. Functional experiments revealed that GREM1 promoted the proliferation and activation of intestinal fibroblast cells by enhancing fatty acid oxidation. Blocking GREM1 prevented the progression of intestinal fibrosis in vivo. Mechanistic research revealed that GREM1 acted as a ligand for VEGFR2 and triggered downstream MAPK signaling. This facilitated the expression of FAO-related genes, consequently enhancing fatty acid oxidation. Taken together, our data indicated that targeting GREM1 could represent a promising therapeutic approach for the treatment of intestinal fibrosis.
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Affiliation(s)
- Yang Yang
- Department of Gastroenterology and the Center of Inflammatory Bowel Disease, West China Hospital, Sichuan University, Chengdu, China.,Lab of Inflammatory Bowel Disease, Clinical Institute of Inflammation and Immunology, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China.,Department of Gastroenterology, Daping Hospital, Army Medical University, Chongqing, China
| | - Qi-Shan Zeng
- Department of Gastroenterology and the Center of Inflammatory Bowel Disease, West China Hospital, Sichuan University, Chengdu, China.,Lab of Inflammatory Bowel Disease, Clinical Institute of Inflammation and Immunology, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Min Zou
- Department of Gastroenterology and the Center of Inflammatory Bowel Disease, West China Hospital, Sichuan University, Chengdu, China.,Lab of Inflammatory Bowel Disease, Clinical Institute of Inflammation and Immunology, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Jian Zeng
- Department of Gastroenterology, Chongqing Traditional Chinese Medicine Hospital, Chongqing, China
| | - Jiao Nie
- Lab of Inflammatory Bowel Disease, Clinical Institute of Inflammation and Immunology, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China.,Department of Geriatrics and National Clinical Research Center for Geriatric, West China Hospital, Sichuan University, Chengdu, China
| | - DongFeng Chen
- Department of Gastroenterology, Daping Hospital, Army Medical University, Chongqing, China
| | - Hua-Tian Gan
- Department of Gastroenterology and the Center of Inflammatory Bowel Disease, West China Hospital, Sichuan University, Chengdu, China.,Lab of Inflammatory Bowel Disease, Clinical Institute of Inflammation and Immunology, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China.,Department of Geriatrics and National Clinical Research Center for Geriatric, West China Hospital, Sichuan University, Chengdu, China
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10
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Playing Jekyll and Hyde-The Dual Role of Lipids in Fatty Liver Disease. Cells 2020; 9:cells9102244. [PMID: 33036257 PMCID: PMC7601321 DOI: 10.3390/cells9102244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/27/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022] Open
Abstract
Lipids play Jekyll and Hyde in the liver. On the one hand, the lipid-laden status of hepatic stellate cells is a hallmark of healthy liver. On the other hand, the opposite is true for lipid-laden hepatocytes—they obstruct liver function. Neglected lipid accumulation in hepatocytes can progress into hepatic fibrosis, a condition induced by the activation of stellate cells. In their resting state, these cells store substantial quantities of fat-soluble vitamin A (retinyl esters) in large lipid droplets. During activation, these lipid organelles are gradually degraded. Hence, treatment of fatty liver disease is treading a tightrope—unsophisticated targeting of hepatic lipid accumulation might trigger problematic side effects on stellate cells. Therefore, it is of great importance to gain more insight into the highly dynamic lipid metabolism of hepatocytes and stellate cells in both quiescent and activated states. In this review, part of the special issue entitled “Cellular and Molecular Mechanisms underlying the Pathogenesis of Hepatic Fibrosis 2020”, we discuss current and highly versatile aspects of neutral lipid metabolism in the pathogenesis of non-alcoholic fatty liver disease (NAFLD).
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11
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Silva CM, Ferrari GD, Alberici LC, Malaspina O, Moraes KCM. Cellular and molecular effects of silymarin on the transdifferentiation processes of LX-2 cells and its connection with lipid metabolism. Mol Cell Biochem 2020; 468:129-142. [PMID: 32185674 DOI: 10.1007/s11010-020-03717-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/06/2020] [Indexed: 12/17/2022]
Abstract
Fibrosis process in the liver is a clinical condition established in response to chronic lesions and may be reversible in many situations. In this process, hepatic stellate cells (HSCs) activate and produce extracellular matrix compounds. During fibrosis, the lipid metabolism is also altered and contributes to the transdifferentiation of the HSCs. Thus, controlling lipid metabolism in HSCs is suggested as a method to control or reverse the fibrotic condition. In the search for therapies that modulate lipid metabolism and treat liver diseases, silymarin has been identified as a relevant natural compound to treat liver pathologies. The present study aimed to evaluate the cellular and molecular effects of silymarin in the transdifferentiation process of HSCs (LX-2) from activated phenotype to a more quiesced-like cells , also focusing on understanding the modulatory effects of silymarin on lipid metabolism of HSCs. In our analyses, 100 µM of silymarin reduced the synthesis of actin filaments in activated cells, the synthesis of the protein level of α-SMA, and other pro-fibrotic factors such as CTGF and PFGF. The concentration of 150 µM silymarin did not reverse the activation aspects of LX-2 cells. However, both evaluated concentrations of the natural compound protected the cells from the negative effects of dimethyl sulfoxide (DMSO). Furthermore, we evaluated lipid-related molecules correlated to the transdifferentiation process of LX-2, and 100 µM of silymarin demonstrated to control molecules associated with lipid metabolism such as FASN, MLYCD, ACSL4, CPTs, among others. In contrast, cellular incubation with 150 µM of silymarin increased the synthesis of long-chain fatty acids and triglycerides, regarding the higher presence of DMSO (v/v) in the solvent. In conclusion, silymarin acts as a hepatoprotective agent and modulates the pro-fibrogenic stimuli of LX-2 cells, whose effects depend on stress levels in the cellular environment.
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Affiliation(s)
- Caio Mateus Silva
- Laboratório de Biologia Molecular, Departamento de Biologia Geral e Aplicada, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Rio Claro, SP, 13506-900, Brazil
| | - Gustavo Duarte Ferrari
- Departamento de Bioquímica E Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto, SP, Brazil
| | - Luciane Carla Alberici
- Departamento de Física E Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto, SP, Brazil
| | - Osmar Malaspina
- Centro de Estudos de Insetos Sociais, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Rio Claro, SP, Brazil
| | - Karen C M Moraes
- Laboratório de Biologia Molecular, Departamento de Biologia Geral e Aplicada, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Rio Claro, SP, 13506-900, Brazil.
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12
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Haaker MW, Vaandrager AB, Helms JB. Retinoids in health and disease: A role for hepatic stellate cells in affecting retinoid levels. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158674. [PMID: 32105672 DOI: 10.1016/j.bbalip.2020.158674] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/13/2022]
Abstract
Vitamin A (retinol) is important for normal growth, vision and reproduction. It has a role in the immune response and the development of metabolic syndrome. Most of the retinol present in the body is stored as retinyl esters within lipid droplets in hepatic stellate cells (HSCs). In case of liver damage, HSCs release large amounts of stored retinol, which is partially converted to retinoic acid (RA). This surge of RA can mediate the immune response and enhance the regeneration of the liver. If the damage persists activated HSCs change into myofibroblast-like cells producing extracellular matrix, which increases the chance of tumorigenesis to occur. RA has been shown to decrease proliferation and metastasis of hepatocellular carcinoma. The levels of RA and RA signaling are influenced by the possibility to esterify retinol towards retinyl esters. This suggests a complex regulation between different retinoids, with an important regulatory role for HSCs.
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Affiliation(s)
- Maya W Haaker
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Arie B Vaandrager
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - J Bernd Helms
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
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13
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Khomich O, Ivanov AV, Bartosch B. Metabolic Hallmarks of Hepatic Stellate Cells in Liver Fibrosis. Cells 2019; 9:E24. [PMID: 31861818 PMCID: PMC7016711 DOI: 10.3390/cells9010024] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/09/2019] [Accepted: 12/18/2019] [Indexed: 12/17/2022] Open
Abstract
Liver fibrosis is a regenerative process that occurs after injury. It is characterized by the deposition of connective tissue by specialized fibroblasts and concomitant proliferative responses. Chronic damage that stimulates fibrogenic processes in the long-term may result in the deposition of excess matrix tissue and impairment of liver functions. End-stage fibrosis is referred to as cirrhosis and predisposes strongly to the loss of liver functions (decompensation) and hepatocellular carcinoma. Liver fibrosis is a pathology common to a number of different chronic liver diseases, including alcoholic liver disease, non-alcoholic fatty liver disease, and viral hepatitis. The predominant cell type responsible for fibrogenesis is hepatic stellate cells (HSCs). In response to inflammatory stimuli or hepatocyte death, HSCs undergo trans-differentiation to myofibroblast-like cells. Recent evidence shows that metabolic alterations in HSCs are important for the trans-differentiation process and thus offer new possibilities for therapeutic interventions. The aim of this review is to summarize current knowledge of the metabolic changes that occur during HSC activation with a particular focus on the retinol and lipid metabolism, the central carbon metabolism, and associated redox or stress-related signaling pathways.
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Affiliation(s)
- Olga Khomich
- INSERM, U1052, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL1), CNRS UMR_5286, Centre Léon Bérard, CEDEX 03, 69424 Lyon, France;
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexander V. Ivanov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Birke Bartosch
- INSERM, U1052, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL1), CNRS UMR_5286, Centre Léon Bérard, CEDEX 03, 69424 Lyon, France;
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14
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Jarc E, Petan T. Lipid Droplets and the Management of Cellular Stress. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:435-452. [PMID: 31543707 PMCID: PMC6747940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Lipid droplets are cytosolic fat storage organelles present in most eukaryotic cells. Long regarded merely as inert fat reservoirs, they are now emerging as major regulators of cellular metabolism. They act as hubs that coordinate the pathways of lipid uptake, distribution, storage, and use in the cell. Recent studies have revealed that they are also essential components of the cellular stress response. One of the hallmark characteristics of lipid droplets is their capacity to buffer excess lipids and to finely tune their subsequent release based on specific cellular requirements. This simple feature of lipid droplet biology, buffering and delayed release of lipids, forms the basis for their pleiotropic roles in the cellular stress response. In stressed cells, lipid droplets maintain energy and redox homeostasis and protect against lipotoxicity by sequestering toxic lipids into their neutral lipid core. Their mobility and dynamic interactions with mitochondria enable an efficient delivery of fatty acids for optimal energy production. Lipid droplets are also involved in the maintenance of membrane and organelle homeostasis by regulating membrane composition, preventing lipid peroxidation and removing damaged proteins and lipids. Finally, they also engage in a symbiotic relationship with autophagy and act as reservoirs of bioactive lipids that regulate inflammation and immunity. Thus, lipid droplets are central managers of lipid metabolism that function as safeguards against various types of cellular stress.
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Affiliation(s)
- Eva Jarc
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia,Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia,To whom all correspondence should be addressed: Toni Petan, Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia; Tel: +386 1 477 3713, Fax: +386 1 477 3984,
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15
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Singh AB, Kan CFK, Kraemer FB, Sobel RA, Liu J. Liver-specific knockdown of long-chain acyl-CoA synthetase 4 reveals its key role in VLDL-TG metabolism and phospholipid synthesis in mice fed a high-fat diet. Am J Physiol Endocrinol Metab 2019; 316:E880-E894. [PMID: 30721098 PMCID: PMC6580179 DOI: 10.1152/ajpendo.00503.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Long-chain acyl-CoA synthetase 4 (ACSL4) has a unique substrate specificity for arachidonic acid. Hepatic ACSL4 is coregulated with the phospholipid (PL)-remodeling enzyme lysophosphatidylcholine (LPC) acyltransferase 3 by peroxisome proliferator-activated receptor δ to modulate the plasma triglyceride (TG) metabolism. In this study, we investigated the acute effects of hepatic ACSL4 deficiency on lipid metabolism in adult mice fed a high-fat diet (HFD). Adenovirus-mediated expression of a mouse ACSL4 shRNA (Ad-shAcsl4) in the liver of HFD-fed mice led to a 43% reduction of hepatic arachidonoyl-CoA synthetase activity and a 53% decrease in ACSL4 protein levels compared with mice receiving control adenovirus (Ad-shLacZ). Attenuated ACSL4 expression resulted in a substantial decrease in circulating VLDL-TG levels without affecting plasma cholesterol. Lipidomics profiling revealed that knocking down ACSL4 altered liver PL compositions, with the greatest impact on accumulation of abundant LPC species (LPC 16:0 and LPC 18:0) and lysophosphatidylethanolamine (LPE) species (LPE 16:0 and LPE 18:0). In addition, fasting glucose and insulin levels were higher in Ad-shAcsl4-transduced mice versus control (Ad-shLacZ). Glucose tolerance testing further indicated an insulin-resistant phenotype upon knockdown of ACSL4. These results provide the first in vivo evidence that ACSL4 plays a role in plasma TG and glucose metabolism and hepatic PL synthesis of hyperlipidemic mice.
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Affiliation(s)
- Amar B Singh
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Chin Fung K Kan
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
- Ochsner Clinical School, University of Queensland School of Medicine , New Orleans, Louisiana
| | - Fredric B Kraemer
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
- Department of Medicine, Stanford University School of Medicine , Stanford, California
- Stanford Diabetes Research Center, Stanford University School of Medicine , Stanford, California
| | - Raymond A Sobel
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
- Department of Pathology, Stanford University School of Medicine , Stanford, California
| | - Jingwen Liu
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
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16
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Shmarakov IO, Jiang H, Liu J, Fernandez EJ, Blaner WS. Hepatic stellate cell activation: A source for bioactive lipids. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:629-642. [PMID: 30735856 DOI: 10.1016/j.bbalip.2019.02.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/30/2019] [Accepted: 02/03/2019] [Indexed: 02/06/2023]
Abstract
Hepatic stellate cells (HSCs) are non-parenchymal liver cells that characteristically contain multiple retinoid (vitamin A)-containing lipid droplets. In this study, we addressed the metabolic fate of non-retinoid lipids originating from lipid droplet loss during HSCs activation. UPLC/MS/MS and qRT-PCR were used to monitor the lipid composition and mRNA expression of selected genes regulating lipid metabolism in freshly isolated, overnight-, 3- and 7-day cultures or primary mouse HSCs. A preferential accumulation of specific C20-C24 fatty acid species, especially arachidonic (C20:4) and docosahexaenoic acids (C22:6), was revealed in culture-activated HSCs along with an upregulation of transcription of fatty acid desaturases (Scd1, Scd2) and elongases (Elovl5, Elovl6). This was accompanied with an enrichment of activated HSCs with 36:4 and 38:4 phosphatidylcholine species containing polyunsaturated fatty acids and associated accumulation of selective lipid mediators, including endocannabinoids and related N-acylethanolamides, as well as ceramides. An increase in 2-arachidonoylglycerol and N-arachydonoylethanolamide concentrations was observed along with an upregulation of Daglα mRNA expression in HSCs during culture activation. N-palmitoylethanolamide was identified as the most abundant endocannabinoid-like species in activated HSCs. An increase in total ceramide levels and enrichment with N-palmitoyl (C16:0), N-tetracosenoyl (C24:1), N-tetracosanoyl (C24:0) and N-docosanoyl (C22:0) ceramides was detected in activated HSC cultures and was preceded by increased mRNA expression of ceramide synthesizing enzymes (CerS2, CerS5 and Smpd1). Our data suggest an active redistribution of non-retinoid lipids in HSCs underlying the formation of low abundance, highly bioactive lipid species that may affect signaling during HSC activation, as well as extracellularly within the liver.
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Affiliation(s)
- Igor O Shmarakov
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA.
| | - Hongfeng Jiang
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
| | - Jing Liu
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
| | - Elias J Fernandez
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37916, USA
| | - William S Blaner
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
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17
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Murphy RC, Folco G. Lysophospholipid acyltransferases and leukotriene biosynthesis: intersection of the Lands cycle and the arachidonate PI cycle. J Lipid Res 2019; 60:219-226. [PMID: 30606731 DOI: 10.1194/jlr.s091371] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/03/2019] [Indexed: 12/18/2022] Open
Abstract
Leukotrienes (LTs) are autacoids derived from the precursor arachidonic acid (AA) via the action of five-lipoxygenase (5-LO). When inflammatory cells are activated, 5-LO translocates to the nuclear membrane to initiate oxygenation of AA released by cytosolic phospholipase A2 (cPLA2) into leukotriene A4 (LTA4). LTA4 can also be exported from an activated donor cell into an acceptor cell by the process of transcellular biosynthesis. When thimerosal is added to cells, the level of free AA increases by inhibition of lysophospholipid acyltransferases of the Lands pathway of phospholipid remodeling. Another arachidonate phospholipid cycle involves phosphatidylinositol (PI) in the plasma membrane that undoubtedly intersects with the Lands pathway of phospholipid remodeling. The highest abundance of PI occurs between the ER and the plasma membrane and is probably a result of the importance of the PI signaling cascade in cellular biochemistry. Because transport proteins mediate the rapid intracellular movement of phospholipids, largely as result of physical membrane contact, 5-LO-dependent production of LTA4 could be mediated by the disappearance of free AA from the nuclear membrane, transfer to the ER for Lands cycle reesterification into PI, and population of PI(18:0/20:4) for cell membrane signaling.
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Affiliation(s)
- Robert C Murphy
- Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045
| | - Giancarlo Folco
- Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045
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18
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Hou W, Syn WK. Role of Metabolism in Hepatic Stellate Cell Activation and Fibrogenesis. Front Cell Dev Biol 2018; 6:150. [PMID: 30483502 PMCID: PMC6240744 DOI: 10.3389/fcell.2018.00150] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/15/2018] [Indexed: 12/12/2022] Open
Abstract
Activation of hepatic stellate cell (HSC) involves the transition from a quiescent to a proliferative, migratory, and fibrogenic phenotype (i.e., myofibroblast), which is characteristic of liver fibrogenesis. Multiple cellular and molecular signals which contribute to HSC activation have been identified. This review specially focuses on the metabolic changes which impact on HSC activation and fibrogenesis.
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Affiliation(s)
- Wei Hou
- Tianjin Second People's Hospital and Tianjin Institute of Hepatology, Tianjin, China.,Division of Gastroenterology and Hepatology, Department of Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Wing-Kin Syn
- Division of Gastroenterology and Hepatology, Department of Medicine, Medical University of South Carolina, Charleston, SC, United States.,Section of Gastroenterology, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States
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19
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Petan T, Jarc E, Jusović M. Lipid Droplets in Cancer: Guardians of Fat in a Stressful World. Molecules 2018; 23:molecules23081941. [PMID: 30081476 PMCID: PMC6222695 DOI: 10.3390/molecules23081941] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022] Open
Abstract
Cancer cells possess remarkable abilities to adapt to adverse environmental conditions. Their survival during severe nutrient and oxidative stress depends on their capacity to acquire extracellular lipids and the plasticity of their mechanisms for intracellular lipid synthesis, mobilisation, and recycling. Lipid droplets, cytosolic fat storage organelles present in most cells from yeast to men, are emerging as major regulators of lipid metabolism, trafficking, and signalling in various cells and tissues exposed to stress. Their biogenesis is induced by nutrient and oxidative stress and they accumulate in various cancers. Lipid droplets act as switches that coordinate lipid trafficking and consumption for different purposes in the cell, such as energy production, protection against oxidative stress or membrane biogenesis during rapid cell growth. They sequester toxic lipids, such as fatty acids, cholesterol and ceramides, thereby preventing lipotoxic cell damage and engage in a complex relationship with autophagy. Here, we focus on the emerging mechanisms of stress-induced lipid droplet biogenesis; their roles during nutrient, lipotoxic, and oxidative stress; and the relationship between lipid droplets and autophagy. The recently discovered principles of lipid droplet biology can improve our understanding of the mechanisms that govern cancer cell adaptability and resilience to stress.
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Affiliation(s)
- Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
| | - Eva Jarc
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
- Jožef Stefan International Postgraduate School, Ljubljana SI-1000, Slovenia.
| | - Maida Jusović
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
- Jožef Stefan International Postgraduate School, Ljubljana SI-1000, Slovenia.
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20
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de Oliveira da Silva B, Alberici LC, Ramos LF, Silva CM, da Silveira MB, Dechant CRP, Friedman SL, Sakane KK, Gonçalves LR, Moraes KCM. Altered global microRNA expression in hepatic stellate cells LX-2 by angiotensin-(1-7) and miRNA-1914-5p identification as regulator of pro-fibrogenic elements and lipid metabolism. Int J Biochem Cell Biol 2018. [PMID: 29524604 DOI: 10.1016/j.biocel.2018.02.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The development of new therapeutic strategies to control or reverse hepatic fibrosis requires thorough knowledge about its molecular and cellular basis. It is known that the heptapeptide angiotensin-(1-7) [ang-(1-7)] can reduce hepatic fibrosis and steatosis in vivo; therefore, it is important to uncover the mechanisms regulating its activity and cellular model of investigation. Ang-(1-7) is a peptide of the renin-angiotensin system (RAS), and here we investigated its modulatory effect on the expression pattern of microRNAs (miRNAs) in hepatic stellate cells (HSCs) LX-2, which transdifferentiate into fibrogenic and proliferative cells. We compared the miRNA profiles between quiesced, activated and ang-(1-7)-treated activated HSCs to identify miRNAs that may regulate their transdifferentiation. Thirteen miRNAs were pointed, and cellular and molecular analyses identified miRNA-1914-5p as a molecule that contributes to the effects of ang-(1-7) on lipid metabolism and on the pro-fibrotic environment control. In our cellular model, we also analyzed the regulators of fatty acid metabolism. Specifically, miRNA-1914-5p regulates the expression of malonyl-CoA decarboxylase (MLYCD) and phosphatidic acid phosphohydrolase (PAP or Lipin-1). Additionally, Lipin-1 was closely correlated with mRNA expression of peroxisome proliferator-activated receptors (PPAR)-α and -γ, which also contribute to lipid homeostasis and to the reduction of TGF-β1 expression. These findings provide a novel link between RAS and lipid metabolism in controlling HSCs activation.
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Affiliation(s)
- Brenda de Oliveira da Silva
- Núcleo de Pesquisa em Biologia, Universidade Federal de Ouro Preto, UFOP, Ouro Preto, MG, Brazil; Molecular Biology Laboratory, Department of Biology, Bioscience Institute, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP, Rio Claro, SP, Brazil
| | - Luciane Carla Alberici
- Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto, SP, Brazil
| | - Letícia Ferreira Ramos
- Molecular Biology Laboratory, Department of Biology, Bioscience Institute, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP, Rio Claro, SP, Brazil
| | - Caio Mateus Silva
- Molecular Biology Laboratory, Department of Biology, Bioscience Institute, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP, Rio Claro, SP, Brazil
| | - Marina Bonfogo da Silveira
- Molecular Biology Laboratory, Department of Biology, Bioscience Institute, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP, Rio Claro, SP, Brazil
| | - Carlos R P Dechant
- Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto, SP, Brazil
| | - Scott L Friedman
- Division of Liver Diseases, Department of Medicine, Mount Sinai School of Medicine, New York, NY, USA
| | - Kumiko Koibuchi Sakane
- Institute of Research and Development of Universidade do Vale do Paraíba, UNIVAP, São José dos Campos, SP, Brazil
| | - Letícia Rocha Gonçalves
- Molecular Biology Laboratory, Department of Biology, Bioscience Institute, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP, Rio Claro, SP, Brazil
| | - Karen C M Moraes
- Molecular Biology Laboratory, Department of Biology, Bioscience Institute, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP, Rio Claro, SP, Brazil.
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21
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Sawama Y, Park K, Yamada T, Sajiki H. New Gateways to the Platinum Group Metal-Catalyzed Direct Deuterium-Labeling Method Utilizing Hydrogen as a Catalyst Activator. Chem Pharm Bull (Tokyo) 2018; 66:21-28. [DOI: 10.1248/cpb.c17-00222] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Kwihwan Park
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University
| | - Tsuyoshi Yamada
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University
| | - Hironao Sajiki
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University
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22
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Molenaar MR, Vaandrager AB, Helms JB. Some Lipid Droplets Are More Equal Than Others: Different Metabolic Lipid Droplet Pools in Hepatic Stellate Cells. Lipid Insights 2017; 10:1178635317747281. [PMID: 29276391 PMCID: PMC5734559 DOI: 10.1177/1178635317747281] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/14/2017] [Indexed: 01/11/2023] Open
Abstract
Hepatic stellate cells (HSCs) are professional lipid-storing cells and are unique in their property to store most of the retinol (vitamin A) as retinyl esters in large-sized lipid droplets. Hepatic stellate cell activation is a critical step in the development of chronic liver disease, as activated HSCs cause fibrosis. During activation, HSCs lose their lipid droplets containing triacylglycerols, cholesteryl esters, and retinyl esters. Lipidomic analysis revealed that the dynamics of disappearance of these different classes of neutral lipids are, however, very different from each other. Although retinyl esters steadily decrease during HSC activation, triacylglycerols have multiple pools one of which becomes transiently enriched in polyunsaturated fatty acids before disappearing. These observations are consistent with the existence of preexisting “original” lipid droplets with relatively slow turnover and rapidly recycling lipid droplets that transiently appear during activation of HSCs. Elucidation of the molecular machinery involved in the regulation of these distinct lipid droplet pools may open new avenues for the treatment of liver fibrosis.
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Affiliation(s)
- Martijn R Molenaar
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
| | - Arie B Vaandrager
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
| | - J Bernd Helms
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
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23
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Complementary ACSL isoforms contribute to a non-Warburg advantageous energetic status characterizing invasive colon cancer cells. Sci Rep 2017; 7:11143. [PMID: 28894242 PMCID: PMC5593891 DOI: 10.1038/s41598-017-11612-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/25/2017] [Indexed: 01/07/2023] Open
Abstract
Metabolic reprogramming is one of cancer hallmarks. Here, we focus on functional differences and individual contribution of acyl coA synthetases (ACSL) isoforms to the previously described ACSL/stearoyl-CoA desaturase (ACSL1/ACSL4/SCD) metabolic network causing invasion and poor prognosis in colorectal cancer (CRC). ACSL4 fuels proliferation and migration accompanied by a more glycolytic phenotype. Conversely, ACSL1 stimulates invasion displaying a lower basal respiratory rate. Acylcarnitines elevation, polyunsaturated fatty acids (PUFA) lower levels, and monounsaturated fatty acids (MUFA) upregulation characterize the individual overexpression of ACSL1, ACSL4 and SCD, respectively. However, the three enzymes simultaneous overexpression results in upregulated phospholipids and urea cycle derived metabolites. Thus, the metabolic effects caused by the network are far from being caused by the individual contributions of each enzyme. Furthermore, ACSL/SCD network produces more energetically efficient cells with lower basal respiration levels and upregulated creatine pathway. These features characterize other invasive CRC cells, thus, ACSL/SCD network exemplifies specific metabolic adaptations for invasive cancer cells.
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Tuohetahuntila M, Molenaar MR, Spee B, Brouwers JF, Wubbolts R, Houweling M, Yan C, Du H, VanderVen BC, Vaandrager AB, Helms JB. Lysosome-mediated degradation of a distinct pool of lipid droplets during hepatic stellate cell activation. J Biol Chem 2017; 292:12436-12448. [PMID: 28615446 DOI: 10.1074/jbc.m117.778472] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/14/2017] [Indexed: 11/06/2022] Open
Abstract
Activation of hepatic stellate cells (HSCs) is a critical step in the development of liver fibrosis. During activation, HSCs lose their lipid droplets (LDs) containing triacylglycerols (TAGs), cholesteryl esters, and retinyl esters (REs). We previously provided evidence for the presence of two distinct LD pools, a preexisting and a dynamic LD pool. Here we investigate the mechanisms of neutral lipid metabolism in the preexisting LD pool. To investigate the involvement of lysosomal degradation of neutral lipids, we studied the effect of lalistat, a specific lysosomal acid lipase (LAL/Lipa) inhibitor on LD degradation in HSCs during activation in vitro The LAL inhibitor increased the levels of TAG, cholesteryl ester, and RE in both rat and mouse HSCs. Lalistat was less potent in inhibiting the degradation of newly synthesized TAG species as compared with a more general lipase inhibitor orlistat. Lalistat also induced the presence of RE-containing LDs in an acidic compartment. However, targeted deletion of the Lipa gene in mice decreased the liver levels of RE, most likely as the result of a gradual disappearance of HSCs in livers of Lipa-/- mice. Lalistat partially inhibited the induction of activation marker α-smooth muscle actin (α-SMA) in rat and mouse HSCs. Our data suggest that LAL/Lipa is involved in the degradation of a specific preexisting pool of LDs and that inhibition of this pathway attenuates HSC activation.
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Affiliation(s)
- Maidina Tuohetahuntila
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - Martijn R Molenaar
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - Bart Spee
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - Jos F Brouwers
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - Richard Wubbolts
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - Martin Houweling
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - Cong Yan
- Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Hong Du
- Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Brian C VanderVen
- Department of Microbiology and Immunology, Cornell University, C5 181 Veterinary Medicine Center, Ithaca, New York 14853
| | - Arie B Vaandrager
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands
| | - J Bernd Helms
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands.
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25
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Ajat M, Molenaar M, Brouwers JFHM, Vaandrager AB, Houweling M, Helms JB. Hepatic stellate cells retain the capacity to synthesize retinyl esters and to store neutral lipids in small lipid droplets in the absence of LRAT. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:176-187. [PMID: 27815220 DOI: 10.1016/j.bbalip.2016.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 10/07/2016] [Accepted: 10/28/2016] [Indexed: 01/20/2023]
Abstract
Hepatic stellate cells (HSCs) play an important role in liver physiology and under healthy conditions they have a quiescent and lipid-storing phenotype. Upon liver injury, HSCs are activated and rapidly lose their retinyl ester-containing lipid droplets. To investigate the role of lecithin:retinol acyltransferase (LRAT) and acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) in retinyl ester synthesis and lipid droplet dynamics, we modified LC-MS/MS procedures by including multiple reaction monitoring allowing unambiguous identification and quantification of all major retinyl ester species. Quiescent primary HSCs contain predominantly retinyl palmitate. Exogenous fatty acids are a major determinant in the retinyl ester species synthesized by activated HSCs and LX-2 cells, indicating that HSCs shift their retinyl ester synthesizing capacity from LRAT to DGAT1 during activation. Quiescent LRAT-/- HSCs retain the capacity to synthesize retinyl esters and to store neutral lipids in lipid droplets ex vivo. The median lipid droplet size in LRAT-/- HSCs (1080nm) is significantly smaller than in wild type HSCs (1618nm). This is a consequence of an altered lipid droplet size distribution with 50.5±9.0% small (≤700nm) lipid droplets in LRAT-/- HSCs and 25.6±1.4% large (1400-2100nm) lipid droplets in wild type HSC cells. Upon prolonged (24h) incubation, the amounts of small (≤700nm) lipid droplets strongly increased both in wild type and in LRAT-/- HSCs, indicating a dynamic behavior in both cell types. The absence of retinyl esters and reduced number of lipid droplets in LRAT-deficient HSCs in vivo will be discussed.
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Affiliation(s)
- Mokrish Ajat
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands
| | - Martijn Molenaar
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands
| | - Jos F H M Brouwers
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands
| | - Arie B Vaandrager
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands
| | - Martin Houweling
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands
| | - J Bernd Helms
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands.
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26
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Alipour H, Raz A, Zakeri S, Dinparast Djadid N. Therapeutic applications of collagenase (metalloproteases): A review. Asian Pac J Trop Biomed 2016. [DOI: 10.1016/j.apjtb.2016.07.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Yamada T, Park K, Yasukawa N, Morita K, Monguchi Y, Sawama Y, Sajiki H. Mild and Direct Multiple Deuterium-Labeling of Saturated Fatty Acids. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600363] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Tsuyoshi Yamada
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Kwihwan Park
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Naoki Yasukawa
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Kosuke Morita
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Yasunari Monguchi
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Yoshinari Sawama
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Hironao Sajiki
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
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28
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Tuohetahuntila M, Molenaar MR, Spee B, Brouwers JF, Houweling M, Vaandrager AB, Helms JB. ATGL and DGAT1 are involved in the turnover of newly synthesized triacylglycerols in hepatic stellate cells. J Lipid Res 2016; 57:1162-74. [PMID: 27179362 DOI: 10.1194/jlr.m066415] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Indexed: 12/15/2022] Open
Abstract
Hepatic stellate cell (HSC) activation is a critical step in the development of chronic liver disease. During activation, HSCs lose their lipid droplets (LDs) containing triacylglycerol (TAG), cholesteryl esters (CEs), and retinyl esters (REs). Here we aimed to investigate which enzymes are involved in LD turnover in HSCs during activation in vitro. Targeted deletion of the Atgl gene in mice HSCs had little effect on the decrease of the overall TAG, CE, and RE levels during activation. However, ATGL-deficient HSCs specifically accumulated TAG species enriched in PUFAs and degraded new TAG species more slowly. TAG synthesis and levels of PUFA-TAGs were lowered by the diacylglycerol acyltransferase (DGAT)1 inhibitor, T863. The lipase inhibitor, Atglistatin, increased the levels of TAG in both WT and ATGL-deficient mouse HSCs. Both Atglistatin and T863 inhibited the induction of activation marker, α-smooth muscle actin, in rat HSCs, but not in mouse HSCs. Compared with mouse HSCs, rat HSCs have a higher turnover of new TAGs, and Atglistatin and the DGAT1 inhibitor, T863, were more effective. Our data suggest that ATGL preferentially degrades newly synthesized TAGs, synthesized by DGAT1, and is less involved in the breakdown of preexisting TAGs and REs in HSCs. Furthermore a large change in TAG levels has modest effect on rat HSC activation.
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Affiliation(s)
- Maidina Tuohetahuntila
- Departments of Biochemistry and Cell Biology Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
| | - Martijn R Molenaar
- Departments of Biochemistry and Cell Biology Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
| | - Bart Spee
- Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
| | - Jos F Brouwers
- Departments of Biochemistry and Cell Biology Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
| | - Martin Houweling
- Departments of Biochemistry and Cell Biology Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
| | - Arie B Vaandrager
- Departments of Biochemistry and Cell Biology Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
| | - J Bernd Helms
- Departments of Biochemistry and Cell Biology Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, 3584 CM Utrecht, The Netherlands
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29
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Lytle KA, Depner CM, Wong CP, Jump DB. Docosahexaenoic acid attenuates Western diet-induced hepatic fibrosis in Ldlr-/- mice by targeting the TGFβ-Smad3 pathway. J Lipid Res 2015; 56:1936-46. [PMID: 26315048 PMCID: PMC4583081 DOI: 10.1194/jlr.m061275] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/27/2015] [Indexed: 02/07/2023] Open
Abstract
DHA (22:6,ω3), but not EPA (20:5,ω3), attenuates Western diet (WD)-induced hepatic fibrosis in a Ldlr(-/-) mouse model of nonalcoholic steatohepatitis. We examined the molecular basis for the differential effect of dietary EPA and DHA on WD-induced hepatic fibrosis. DHA was more effective than EPA at preventing WD-induced effects on hepatic transcripts linked to fibrosis, including collagen 1A1 (Col1A1), transforming growth factor-β (TGFβ) signaling and proteins involved in remodeling the extracellular matrix, including metalloproteases, tissue inhibitors of metalloproteases, and lysyl oxidase subtypes. Examination of the TGFβ pathway showed that mice fed the WD supplemented with either olive oil or EPA had a significant (≥2.5-fold) increase in hepatic nuclear abundance of phospho-mothers against decapentaplegic homolog (Smad)3 when compared with mice fed the reference diet (RD); Smad3 is a key regulator of Col1A1 expression in stellate cells. In contrast, mice fed the WD supplemented with DHA had no increase in phospho-Smad3 when compared with mice fed the RD. Changes in hepatic phospho-Smad3 nuclear content correlated with proCol1A1 mRNA and protein abundance. Pretreatment of human LX2 stellate cells with DHA, but not other unsaturated fatty acids, blocked TGFβ1-mediated induction of Col1A1. In conclusion, DHA attenuates WD-induced fibrosis by targeting the TGFβ-Smad3-Col1A1 pathway in stellate cells.
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Affiliation(s)
- Kelli A. Lytle
- Nutrition Program, School of Biological and Population Health Sciences, Linus Pauling Institute, Oregon State University, Corvallis, OR 97331
| | - Christopher M. Depner
- Nutrition Program, School of Biological and Population Health Sciences, Linus Pauling Institute, Oregon State University, Corvallis, OR 97331
| | - Carmen P. Wong
- Nutrition Program, School of Biological and Population Health Sciences, Linus Pauling Institute, Oregon State University, Corvallis, OR 97331
| | - Donald B. Jump
- Nutrition Program, School of Biological and Population Health Sciences, Linus Pauling Institute, Oregon State University, Corvallis, OR 97331
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30
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Kuwata H, Hara S. Inhibition of long-chain acyl-CoA synthetase 4 facilitates production of 5, 11-dihydroxyeicosatetraenoic acid via the cyclooxygenase-2 pathway. Biochem Biophys Res Commun 2015; 465:528-33. [PMID: 26282205 DOI: 10.1016/j.bbrc.2015.08.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 08/12/2015] [Indexed: 12/16/2022]
Abstract
Long chain acyl-CoA synthetases (ACSLs) are a family of enzymes that convert free long chain fatty acids into their acyl-CoA forms. Among ACSL enzymes, ACSL4 prefers arachidonic acid (AA) as a substrate and plays an important role in re-esterification of free AA. We previously reported that the suppression of ACSL4 activity by treatment with an ACSL inhibitor or a small interfering RNA markedly enhanced interleukin-1β (IL-1β)-dependent prostaglandin (PG) biosynthesis in rat fibroblastic 3Y1 cells. We show here that in addition to these prostanoids, cytokine-dependent production of 5,11-dihydroxyeicosatetraenoic acid (5,11-diHETE), a cyclooxygenase product of 5-hydroxyeicosatetraenoic acid (5-HETE), was enhanced by the inhibition of ACSL4 activity. Treatment of several types of cells with an ACSL inhibitor, triacsin C, markedly enhanced IL-1β-dependent production of 5,11-diHETE. siRNA-mediated knockdown of ACSL4 also enhanced IL-1β-dependent production of 5,11-diHETE from 3Y1 cells. The production of 5,11-diHETE was significantly decreased by a cyclooxygenase (COX)-2 selective inhibitor, NS-398, but not by a 5-lipoxygenase activating protein (FLAP) inhibitor, MK-886. The inhibition of ACSL enzymes significantly facilitated release of not only 5-HETE but also 8-HETE, 9-HETE, 11-HETE, 12-HETE, and 15-HETE, independently of IL-1β stimulation. In vitro analysis showed that a recombinant COX-2 enzyme more effectively metabolized 5(S)-HETE to 5-11-diHETE compared to COX-1 enzyme. From these results, we proposed the following mechanism of 5,11-diHETE biosynthesis in these cells: 1) inhibition of ACSL4 causes accumulation of free AA; 2) the accumulated AA is nonspecifically converted into various HETEs; and 3) among these HETEs, 5-HETE is metabolized into 5,11-diHETE by cytokine-induced COX-2.
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Affiliation(s)
- Hiroshi Kuwata
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
| | - Shuntaro Hara
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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31
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Dichlberger A, Schlager S, Kovanen PT, Schneider WJ. Lipid droplets in activated mast cells - a significant source of triglyceride-derived arachidonic acid for eicosanoid production. Eur J Pharmacol 2015; 785:59-69. [PMID: 26164793 DOI: 10.1016/j.ejphar.2015.07.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/28/2015] [Accepted: 07/07/2015] [Indexed: 12/17/2022]
Abstract
Mast cells are potent effectors of immune reactions and key players in various inflammatory diseases such as atherosclerosis, asthma, and rheumatoid arthritis. The cellular defense response of mast cells represents a unique and powerful system, where external signals can trigger cell activation resulting in a stimulus-specific and highly coordinated release of a plethora of bioactive mediators. The arsenal of mediators encompasses preformed molecules stored in cytoplasmic secretory granules, as well as newly synthesized proteinaceous and lipid mediators. The release of mediators occurs in strict chronological order and requires proper coordination between the endomembrane system and various enzymatic machineries. For the generation of lipid mediators, cytoplasmic lipid droplets have been shown to function as a major intracellular pool of arachidonic acid, the precursor for eicosanoid biosynthesis. Recent studies have revealed that not only phospholipids in mast cell membranes, but also triglycerides in mast cell lipid droplets are a substrate source for eicosanoid formation. The present review summarizes current knowledge about mast cell lipid droplet biology, and discusses expansions and challenges of traditional mechanistic models for eicosanoid production.
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Affiliation(s)
- Andrea Dichlberger
- Wihuri Research Institute, Biomedicum Helsinki 1, Haartmaninkatu 8, 00290 Helsinki, Finland; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria.
| | - Stefanie Schlager
- Medical University of Graz, Institute of Molecular Biology and Biochemistry, Harrachgasse 21, 8010 Graz, Austria; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria
| | - Petri T Kovanen
- Wihuri Research Institute, Biomedicum Helsinki 1, Haartmaninkatu 8, 00290 Helsinki, Finland; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria
| | - Wolfgang J Schneider
- Wihuri Research Institute, Biomedicum Helsinki 1, Haartmaninkatu 8, 00290 Helsinki, Finland; Medical University of Graz, Institute of Molecular Biology and Biochemistry, Harrachgasse 21, 8010 Graz, Austria; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria
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32
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Cooper DE, Young PA, Klett EL, Coleman RA. Physiological Consequences of Compartmentalized Acyl-CoA Metabolism. J Biol Chem 2015; 290:20023-31. [PMID: 26124277 DOI: 10.1074/jbc.r115.663260] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Meeting the complex physiological demands of mammalian life requires strict control of the metabolism of long-chain fatty acyl-CoAs because of the multiplicity of their cellular functions. Acyl-CoAs are substrates for energy production; stored within lipid droplets as triacylglycerol, cholesterol esters, and retinol esters; esterified to form membrane phospholipids; or used to activate transcriptional and signaling pathways. Indirect evidence suggests that acyl-CoAs do not wander freely within cells, but instead, are channeled into specific pathways. In this review, we will discuss the evidence for acyl-CoA compartmentalization, highlight the key modes of acyl-CoA regulation, and diagram potential mechanisms for controlling acyl-CoA partitioning.
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Affiliation(s)
| | | | - Eric L Klett
- From the Departments of Nutrition and Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
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