51
|
Yang XD, Chen Z, Ye L, Chen J, Yang YY. Esculin protects against methionine choline-deficient diet-induced non-alcoholic steatohepatitis by regulating the Sirt1/NF- κB p65 pathway. PHARMACEUTICAL BIOLOGY 2021; 59:922-932. [PMID: 34243681 PMCID: PMC8274538 DOI: 10.1080/13880209.2021.1945112] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 05/10/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
CONTEXT Esculin, an active coumarin compound, has been demonstrated to exert anti-inflammatory effects. However, its potential role in non-alcoholic steatohepatitis (NASH) remains unclear. OBJECTIVE This study explored the hepatoprotective effect and the molecular mechanism of esculin in methionine choline-deficient (MCD) diet-induced NASH. MATERIALS AND METHODS Fifty C57BL/6J mice were divided into five groups: control, model, low dosage esculin (oral, 20 mg/kg), high dosage esculin (oral, 40 mg/kg), and silybin (oral, 105 mg/kg). All animals were fed a MCD diet, except those in the control group (control diet), for 6 weeks. RESULTS Esculin (20 and 40 mg/kg) inhibited MCD diet-induced hepatic lipid content (triglyceride: 16.95 ± 0.67 and 14.85 ± 0.78 vs. 21.21 ± 1.13 mg/g; total cholesterol: 5.10 ± 0.34 and 4.08 ± 0.47 vs. 7.31 ± 0.58 mg/g), fibrosis, and inflammation (ALT: 379.61 ± 40.30 and 312.72 ± 21.45 vs. 559.51 ± 37.01 U/L; AST: 428.22 ± 34.29 and 328.23 ± 23.21 vs. 579.36 ± 31.93 U/L). In vitro, esculin reduced tumour necrosis factor-α, interleukin-6, fibronectin, and collagen 4A1 levels, but had no effect on lipid levels in HepG2 cells induced by free fatty acid. Esculin increased Sirt1 expression levels and decreased NF-κB acetylation levels in vivo and in vitro. Interfering with Sirt1 expression attenuated the beneficial effect of esculin on inflammatory and fibrotic factor production in HepG2 cells. CONCLUSIONS These findings demonstrate that esculin ameliorates MCD diet-induced NASH by regulating the Sirt1/ac-NF-κB signalling pathway. Esculin could thus be employed as a therapy for NASH.
Collapse
Affiliation(s)
- Xi-Ding Yang
- Department of Pharmacy, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Hunan Provincial Engineering Research Central of Translational Medical and Innovative Drug, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Zhuo Chen
- Department of Geriatrics, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Ling Ye
- Department of Geriatrics, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jing Chen
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| | - Yong-Yu Yang
- Department of Pharmacy, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Hunan Provincial Engineering Research Central of Translational Medical and Innovative Drug, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| |
Collapse
|
52
|
The structural basis for the phospholipid remodeling by lysophosphatidylcholine acyltransferase 3. Nat Commun 2021; 12:6869. [PMID: 34824256 PMCID: PMC8617236 DOI: 10.1038/s41467-021-27244-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/08/2021] [Indexed: 12/18/2022] Open
Abstract
As the major component of cell membranes, phosphatidylcholine (PC) is synthesized de novo in the Kennedy pathway and then undergoes extensive deacylation-reacylation remodeling via Lands' cycle. The re-acylation is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT) and among the four LPCAT members in human, the LPCAT3 preferentially introduces polyunsaturated acyl onto the sn-2 position of lysophosphatidylcholine, thereby modulating the membrane fluidity and membrane protein functions therein. Combining the x-ray crystallography and the cryo-electron microscopy, we determined the structures of LPCAT3 in apo-, acyl donor-bound, and acyl receptor-bound states. A reaction chamber was revealed in the LPCAT3 structure where the lysophosphatidylcholine and arachidonoyl-CoA were positioned in two tunnels connected near to the catalytic center. A side pocket was found expanding the tunnel for the arachidonoyl CoA and holding the main body of arachidonoyl. The structural and functional analysis provides the basis for the re-acylation of lysophosphatidylcholine and the substrate preference during the reactions.
Collapse
|
53
|
Chean J, Chen CJ, Gugiu G, Wong P, Cha S, Li H, Nguyen T, Bhatticharya S, Shively JE. Human CEACAM1-LF regulates lipid storage in HepG2 cells via fatty acid transporter CD36. J Biol Chem 2021; 297:101311. [PMID: 34666041 PMCID: PMC8577156 DOI: 10.1016/j.jbc.2021.101311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/07/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022] Open
Abstract
Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed in the liver and secreted as biliary glycoprotein 1 (BGP1) via bile canaliculi (BCs). CEACAM1-LF is a 72 amino acid cytoplasmic domain mRNA splice isoform with two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Ceacam1−/− or Ser503Ala transgenic mice have been shown to develop insulin resistance and nonalcoholic fatty liver disease; however, the role of the human equivalent residue, Ser508, in lipid dysregulation is unknown. Human HepG2 hepatocytes that express CEACAM1 and form BC in vitro were compared with CEACAM1−/− cells and CEACAM1−/− cells expressing Ser508Ala null or Ser508Asp phosphorylation mimic mutations or to phosphorylation null mutations in the tyrosine ITIMs known to be phosphorylated by the tyrosine kinase Src. CEACAM1−/− cells and the Ser508Asp and Tyr520Phe mutants strongly retained lipids, while Ser508Ala and Tyr493Phe mutants had low lipid levels compared with wild-type cells, indicating that the ITIM mutants phenocopied the Ser508 mutants. We found that the fatty acid transporter CD36 was upregulated in the S508A mutant, coexpressed in BCs with CEACAM1, co-IPed with CEACAM1 and Src, and when downregulated via RNAi, an increase in lipid droplet content was observed. Nuclear translocation of CD36 associated kinase LKB1 was increased sevenfold in the S508A mutant versus CEACAM1−/− cells and correlated with increased activation of CD36-associated kinase AMPK in CEACAM1−/− cells. Thus, while CEACAM1−/− HepG2 cells upregulate lipid storage similar to Ceacam1−/− in murine liver, the null mutation Ser508Ala led to decreased lipid storage, emphasizing evolutionary changes between the CEACAM1 genes in mouse and humans.
Collapse
Affiliation(s)
- Jennifer Chean
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Charng-Jui Chen
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Gabriel Gugiu
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Patty Wong
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Seung Cha
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Harry Li
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Tung Nguyen
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Supriyo Bhatticharya
- Department of Computational and Quantitative Medicine, Beckman Research Institute of City of Hope, Duarte, California, USA
| | - John E Shively
- Department of Immunology and Theranostics, Beckman Research Institute of City of Hope, Duarte, California, USA.
| |
Collapse
|
54
|
Nilsson Å, Duan RD, Ohlsson L. Digestion and Absorption of Milk Phospholipids in Newborns and Adults. Front Nutr 2021; 8:724006. [PMID: 34490332 PMCID: PMC8417471 DOI: 10.3389/fnut.2021.724006] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/19/2021] [Indexed: 12/25/2022] Open
Abstract
Milk polar lipids provide choline, ethanolamine, and polyunsaturated fatty acids, which are needed for the growth and plasticity of the tissues in a suckling child. They may also inhibit cholesterol absorption by interacting with cholesterol during micelle formation. They may also have beneficial luminal, mucosal, and metabolic effects in both the neonate and the adult. The milk fat globule membrane contains large proportions of sphingomyelin (SM), phosphatidylcholine (PC), and phosphatidylethanolamine (PE), and some phosphatidylserine (PS), phosphatidylinositol (PI), and glycosphingolipids. Large-scale technical procedures are available for the enrichment of milk fat globule membrane (MFGM) in milk replacement formulations and food additives. Pancreatic phospholipase A2 (PLA2) and mucosal phospholipase B digest glycero-phospholipids in the adult. In the neonate, where these enzymes may be poorly expressed, pancreatic lipase-related protein 2 probably has a more important role. Mucosal alkaline SM-ase and ceramidase catalyze the digestion of SM in both the neonate and the adult. In the mucosa, the sphingosine is converted into sphingosine-1-phosphate, which is both an intermediate in the conversion to palmitic acid and a signaling molecule. This reaction sequence also generates ethanolamine. Here, we summarize the pathways by which digestion and absorption may be linked to the biological effects of milk polar lipids. In addition to the inhibition of cholesterol absorption and the generation of lipid signals in the gut, the utilization of absorbed choline and ethanolamine for mucosal and hepatic phospholipid synthesis and the acylation of absorbed lyso-PC with polyunsaturated fatty acids to chylomicron and mucosal phospholipids are important.
Collapse
Affiliation(s)
- Åke Nilsson
- Division of Medicine, Gastroenterology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Rui-Dong Duan
- Gastroenterology and Nutrition Laboratory, Division of Medicine, Department of Clinical Science, Lund University, Lund, Sweden
| | - Lena Ohlsson
- Division of Medicine, Experimental Vascular Medicine, Department of Clinical Science, Lund University, Lund, Sweden
| |
Collapse
|
55
|
Perspectives on Mitochondria-ER and Mitochondria-Lipid Droplet Contact in Hepatocytes and Hepatic Lipid Metabolism. Cells 2021; 10:cells10092273. [PMID: 34571924 PMCID: PMC8472694 DOI: 10.3390/cells10092273] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 12/11/2022] Open
Abstract
Emerging evidence suggests that mitochondrion–endoplasmic reticulum (ER) and mitochondrion–lipid droplet (LD) contact sites are critical in regulating lipid metabolism in cells. It is well established that intracellular organelles communicate with each other continuously through membrane contact sites to maintain organelle function and cellular homeostasis. The accumulation of LDs in hepatocytes is an early indicator of non-alcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD), which may indicate a breakdown in proper inter-organelle communication. In this review, we discuss previous findings in mitochondrion–ER and mitochondrion–LD contact, focusing on their roles in lipid metabolism in hepatocytes. We also present evidence of a unique mitochondrion–LD contact structure in hepatocytes under various physiological and pathological conditions and propose a working hypothesis to speculate about the role of these structures in regulating the functions of mitochondria and LDs and their implications in NAFLD and ALD.
Collapse
|
56
|
Chen S, Wu Q, Zhu L, Zong G, Li H, Zheng H, Zeng R, Lin X, Sun L. Plasma glycerophospholipid profile, erythrocyte n-3 PUFAs, and metabolic syndrome incidence: a prospective study in Chinese men and women. Am J Clin Nutr 2021; 114:143-153. [PMID: 33829226 DOI: 10.1093/ajcn/nqab050] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/09/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Animal studies have highlighted critical roles of glycerophospholipid (GP) metabolism in various metabolic syndrome (MetS)-related features such as dyslipidemia, obesity, and insulin resistance. However, human prospective studies of associations between circulating GPs and risks of MetS are scarce. OBJECTIVES We aimed to investigate whether GPs are associated with incidence of MetS in a well-established cohort. METHODS A total of 1243 community-dwelling Chinese aged 50-70 y without MetS at baseline and followed up for 6 y were included in current analyses. A total of 145 plasma GPs were quantified by high-throughput targeted lipidomics. MetS was defined using the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans. RESULTS After 6 y, 429 participants developed MetS. Eleven GPs, especially those with long-chain polyunsaturated fatty acids (LCPUFAs) or very-long-chain polyunsaturated fatty acids (VLCPUFAs) at the sn-2 position, including 1 phosphatidylcholine (PC) [PC(18:0/22:6)], 9 phosphatidylethanolamines (PEs) [PE(16:0/22:6), PE(18:0/14:0), PE(18:0/18:1), PE(18:0/18:2), PE(18:0/20:3), PE(18:0/22:5), PE(18:0/22:6), PE(18:1/22:6), and PE(18:2/22:6)], and 1 phosphatidylserine (PS) [PS(18:0/18:0)], were positively associated with incident MetS (RRs: 1.16-1.30 per SD change; Bonferroni-corrected P < 0.05). In network analysis, the strongest positive association for MetS incidence was evidenced in a module mainly composed of PEs containing C22:6 and PSs [RR: 1.21; 95% CI: 1.12, 1.31 per SD change; Bonferroni-corrected P < 0.05]. This association was more pronounced in participants with lower erythrocyte total n-3 PUFA concentrations [Bonferroni-corrected Pinter(P value for the interaction)< 0.05]. CONCLUSIONS Elevated plasma concentrations of GPs, especially PEs with LCPUFAs or VLCPUFAs at the sn-2 position, are associated with higher risk of incident MetS. Future studies are merited to confirm our findings.
Collapse
Affiliation(s)
- Shuangshuang Chen
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qingqing Wu
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Li Zhu
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Geng Zong
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Huaixing Li
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - He Zheng
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rong Zeng
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Systems Biology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Hangzhou, China
| | - Xu Lin
- Key Laboratory of Systems Biology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Hangzhou, China.,Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Liang Sun
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
57
|
Kim S, Voth GA. Physical Characterization of Triolein and Implications for Its Role in Lipid Droplet Biogenesis. J Phys Chem B 2021; 125:6874-6888. [PMID: 34139844 DOI: 10.1021/acs.jpcb.1c03559] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lipid droplets (LDs) are neutral lipid-storing organelles surrounded by a phospholipid (PL) monolayer. At present, how LDs are formed in the endoplasmic reticulum (ER) bilayer is poorly understood. In this study, we present a revised all-atom (AA) triolein (TG) model, the main constituent of the LD core, and characterize its properties in a bilayer membrane to demonstrate the implications of its behavior in LD biogenesis. In bilayer simulations, TG resides at the surface, adopting PL-like conformations (denoted in this work as SURF-TG). Free energy sampling simulation results estimate the barrier for TG relocating from the bilayer surface to the bilayer center to be ∼2 kcal/mol in the absence of an oil lens. SURF-TG is able to modulate membrane properties by increasing PL ordering, decreasing bending modulus, and creating local negative curvature. The other neutral lipid, dioleoyl-glycerol (DAG), also reduces the membrane bending modulus and populates negative curvature regions. A phenomenological coarse-grained (CG) model is also developed to observe larger-scale SURF-TG-mediated membrane deformation. CG simulations confirm that TG nucleates between the bilayer leaflets at a critical concentration when SURF-TG is evenly distributed. However, when one monolayer contains more SURF-TG, the membrane bends toward the other leaflet, followed by TG nucleation if a concentration is higher than the critical threshold. The central conclusion of this study is that SURF-TG is a negative curvature inducer, as well as a membrane modulator. To this end, a model is proposed in which the accumulation of SURF-TG in the luminal leaflet bends the ER bilayer toward the cytosolic side, followed by TG nucleation.
Collapse
Affiliation(s)
- Siyoung Kim
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| |
Collapse
|
58
|
Hayashi Y, Lee-Okada HC, Nakamura E, Tada N, Yokomizo T, Fujiwara Y, Ichi I. Ablation of fatty acid desaturase 2 (FADS2) exacerbates hepatic triacylglycerol and cholesterol accumulation in polyunsaturated fatty acid-depleted mice. FEBS Lett 2021; 595:1920-1932. [PMID: 34008174 DOI: 10.1002/1873-3468.14134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/22/2021] [Accepted: 05/10/2021] [Indexed: 12/14/2022]
Abstract
Deficiency of polyunsaturated fatty acids (PUFAs) is known to induce hepatic steatosis. However, it is not clearly understood which type of PUFA is responsible for the worsening of steatosis. This study observed a marked accumulation of hepatic triacylglycerol and cholesterol in fatty acid desaturase 2 knockout (FADS2-/- ) mice lacking both C18 and ≥ C20 PUFAs that were fed a PUFA-depleted diet. Hepatic triacylglycerol accumulation was associated with enhanced sterol regulatory element-binding protein (SREBP)-1-dependent lipogenesis and decreased triacylglycerol secretion into the plasma via very-low-density lipoprotein (VLDL). Furthermore, upregulation of cholesterol synthesis contributed to increased hepatic cholesterol content in FADS2-/- mice. These results suggest that ≥ C20 PUFAs synthesized by FADS2 are important in regulating hepatic triacylglycerol and cholesterol accumulation during PUFA deficiency.
Collapse
Affiliation(s)
- Yuri Hayashi
- Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo, Japan
| | - Hyeon-Cheol Lee-Okada
- Department of Biochemistry, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Eri Nakamura
- Laboratory of Genome Research, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Norihiro Tada
- Laboratory of Genome Research, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takehiko Yokomizo
- Department of Biochemistry, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yoko Fujiwara
- Institute for Human Life Innovation, Ochanomizu University, Tokyo, Japan.,Natural Science Division, Faculty of Core Research, Ochanomizu University, Tokyo, Japan
| | - Ikuyo Ichi
- Institute for Human Life Innovation, Ochanomizu University, Tokyo, Japan.,Natural Science Division, Faculty of Core Research, Ochanomizu University, Tokyo, Japan
| |
Collapse
|
59
|
Kadri L, Bacle A, Khoury S, Vandebrouck C, Bescond J, Faivre JF, Ferreira T, Sebille S. Polyunsaturated Phospholipids Increase Cell Resilience to Mechanical Constraints. Cells 2021; 10:937. [PMID: 33920685 PMCID: PMC8073313 DOI: 10.3390/cells10040937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 11/24/2022] Open
Abstract
If polyunsaturated fatty acids (PUFAs) are generally accepted to be good for health, the mechanisms of their bona fide benefits still remain elusive. Membrane phospholipids (PLs) of the cardiovascular system and skeletal muscles are particularly enriched in PUFAs. The fatty acid composition of PLs is known to regulate crucial membrane properties, including elasticity and plasticity. Since muscle cells undergo repeated cycles of elongation and relaxation, we postulated in the present study that PUFA-containing PLs could be central players for muscle cell adaptation to mechanical constraints. By a combination of in cellulo and in silico approaches, we show that PUFAs, and particularly the ω-3 docosahexaenoic acid (DHA), regulate important properties of the plasma membrane that improve muscle cell resilience to mechanical constraints. Thanks to their unique property to contortionate within the bilayer plane, they facilitate the formation of vacuole-like dilation (VLD), which, in turn, avoid cell breakage under mechanical constraints.
Collapse
|
60
|
Wolfgang MJ. Remodeling glycerophospholipids affects obesity-related insulin signaling in skeletal muscle. J Clin Invest 2021; 131:148176. [PMID: 33855969 DOI: 10.1172/jci148176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
It has long been known that fatty acids can either adversely or positively affect insulin signaling in skeletal muscle, depending on chain length or saturation, and can therefore be primary drivers of systemic insulin sensitivity. However, the detailed mechanisms linking fatty acids to insulin signaling in skeletal muscle have been elusive. In this issue of the JCI, Ferrara et al. suggest a model whereby membrane lipid remodeling mediates skeletal muscle insulin sensitivity. The authors demonstrate that membrane glycerophospholipid fatty acid remodeling by lysophosphatidylcholine acyltransferase 3 (LPCAT3) in skeletal muscle from subjects with obesity was induced, suppressing insulin signaling and glucose tolerance. Loss or gain of LPCAT3 function in mouse models showed that Lpcat3 was both required and sufficient for high-fat diet-induced muscle insulin resistance. These results suggest that the physiochemical properties of muscle cell membranes may drive insulin sensitivity and, therefore, systemic glucose intolerance.
Collapse
Affiliation(s)
- Michael J Wolfgang
- Department of Biological Chemistry.,Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
61
|
Ferrara PJ, Rong X, Maschek JA, Verkerke AR, Siripoksup P, Song H, Green TD, Krishnan KC, Johnson JM, Turk J, Houmard JA, Lusis AJ, Drummond MJ, McClung JM, Cox JE, Shaikh SR, Tontonoz P, Holland WL, Funai K. Lysophospholipid acylation modulates plasma membrane lipid organization and insulin sensitivity in skeletal muscle. J Clin Invest 2021; 131:135963. [PMID: 33591957 DOI: 10.1172/jci135963] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/11/2021] [Indexed: 01/09/2023] Open
Abstract
Aberrant lipid metabolism promotes the development of skeletal muscle insulin resistance, but the exact identity of lipid-mediated mechanisms relevant to human obesity remains unclear. A comprehensive lipidomic analysis of primary myocytes from individuals who were insulin-sensitive and lean (LN) or insulin-resistant with obesity (OB) revealed several species of lysophospholipids (lyso-PLs) that were differentially abundant. These changes coincided with greater expression of lysophosphatidylcholine acyltransferase 3 (LPCAT3), an enzyme involved in phospholipid transacylation (Lands cycle). Strikingly, mice with skeletal muscle-specific knockout of LPCAT3 (LPCAT3-MKO) exhibited greater muscle lysophosphatidylcholine/phosphatidylcholine, concomitant with improved skeletal muscle insulin sensitivity. Conversely, skeletal muscle-specific overexpression of LPCAT3 (LPCAT3-MKI) promoted glucose intolerance. The absence of LPCAT3 reduced phospholipid packing of cellular membranes and increased plasma membrane lipid clustering, suggesting that LPCAT3 affects insulin receptor phosphorylation by modulating plasma membrane lipid organization. In conclusion, obesity accelerates the skeletal muscle Lands cycle, whose consequence might induce the disruption of plasma membrane organization that suppresses muscle insulin action.
Collapse
Affiliation(s)
- Patrick J Ferrara
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Xin Rong
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California, USA
| | - J Alan Maschek
- Diabetes and Metabolism Research Center and.,Metabolomics, Mass Spectrometry, and Proteomics Core and
| | - Anthony Rp Verkerke
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA
| | - Piyarat Siripoksup
- Diabetes and Metabolism Research Center and.,Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, USA
| | - Haowei Song
- Division of Endocrinology Metabolism and Lipid Research, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | | | - Jordan M Johnson
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA
| | - John Turk
- Division of Endocrinology Metabolism and Lipid Research, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joseph A Houmard
- East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA
| | - Aldons J Lusis
- Cardiology Division, Department of Medicine, UCLA, Los Angeles, California, USA
| | - Micah J Drummond
- Diabetes and Metabolism Research Center and.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA.,Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, USA
| | | | - James E Cox
- Diabetes and Metabolism Research Center and.,Metabolomics, Mass Spectrometry, and Proteomics Core and.,Department of Biochemistry, University of Utah, Salt Lake City, Utah, USA
| | - Saame Raza Shaikh
- East Carolina Diabetes and Obesity Institute and.,Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California, USA
| | - William L Holland
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Katsuhiko Funai
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA.,Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
62
|
Russo-Savage L, Schulman IG. Liver X receptors and liver physiology. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166121. [PMID: 33713792 DOI: 10.1016/j.bbadis.2021.166121] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 12/29/2022]
Abstract
The liver x receptors LXRα (NR1H3) and LXRβ (NR1H2) are members of the nuclear hormone receptor superfamily of ligand dependent transcription factors that regulate transcription in response to the direct binding of cholesterol derivatives. Studies using genetic knockouts and synthetic ligands have defined the LXRs as important modulators of lipid homeostasis throughout the body. This review focuses on the control of cholesterol and fatty acid metabolism by LXRs in the liver and how modifying LXR activity can influence the pathology of liver diseases.
Collapse
Affiliation(s)
- Lillian Russo-Savage
- Department of Pharmacology, University of Virginia, School of Medicine, United States of America
| | - Ira G Schulman
- Department of Pharmacology, University of Virginia, School of Medicine, United States of America.
| |
Collapse
|
63
|
Shah S, Fillier T, Pham TH, Thomas R, Cheema SK. Intraperitoneal Administration of Short-Chain Fatty Acids Improves Lipid Metabolism of Long-Evans Rats in a Sex-Specific Manner. Nutrients 2021; 13:nu13030892. [PMID: 33801984 PMCID: PMC8000072 DOI: 10.3390/nu13030892] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 01/01/2023] Open
Abstract
Short-chain fatty acids (SCFAs) are microbial metabolites, mainly generated by the action of gut microbiota on dietary fibers. Acetate, propionate, and butyrate are the three main SCFAs produced typically in a 60:20:20 molar ratio in the colon. Acetate, propionate, and butyrate, when given individually as supplements, have shown a protective role in obesity and hyperglycemia; however, the sex-specific effects of a mixture of SCFAs, when given in 60:20:20 ratio, on the regulation of lipid metabolism and lipid profile are not known. Male and female Long-Evans rats were given a mixture of SCFAs (acetate, propionate, and butyrate; molar ratio 60:20:20) each day for seven days intraperitoneally; plasma and hepatic lipids, gene expression, and lipidomics profile were analyzed. SCFAs significantly decreased plasma and hepatic triglycerides and cholesterol in males, whereas the fatty acyl composition of cholesteryl esters, triglycerides, and phospholipids was modulated in females. SCFAs decreased the mRNA expression of hepatic acetyl-CoA carboxylase-1 in both males and females. Our findings demonstrate for the first time that SCFAs (60:20:20) improved plasma and hepatic lipid levels and fatty acyl composition in a manner that may provide cardio-protective and anti-inflammatory effects in both sexes, via independent mechanisms.
Collapse
Affiliation(s)
- Shrushti Shah
- Department of Biochemistry, Memorial University of Newfoundland, St. John’s, NL A1B 3X9, Canada;
| | - Tiffany Fillier
- School of Science and the Environment/Boreal Ecosystem Research Initiative, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL A2H 5G4, Canada; (T.F.); (T.H.P.); (R.T.)
| | - Thu Huong Pham
- School of Science and the Environment/Boreal Ecosystem Research Initiative, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL A2H 5G4, Canada; (T.F.); (T.H.P.); (R.T.)
| | - Raymond Thomas
- School of Science and the Environment/Boreal Ecosystem Research Initiative, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL A2H 5G4, Canada; (T.F.); (T.H.P.); (R.T.)
| | - Sukhinder Kaur Cheema
- Department of Biochemistry, Memorial University of Newfoundland, St. John’s, NL A1B 3X9, Canada;
- Correspondence: ; Tel.: +1-709-864-3987; Fax: +1-709-864-2422
| |
Collapse
|
64
|
Xia M, Chandrasekaran P, Rong S, Fu X, Mitsche MA. Hepatic deletion of Mboat7 (LPIAT1) causes activation of SREBP-1c and fatty liver. J Lipid Res 2021; 62:100031. [PMID: 32859645 PMCID: PMC8022244 DOI: 10.1194/jlr.ra120000856] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/30/2020] [Indexed: 12/13/2022] Open
Abstract
Genetic variants that increase the risk of fatty liver disease and cirrhosis have recently been identified in the proximity of membrane-bound O-acyltransferase domain-containing 7 (MBOAT7). To elucidate the link between these variants and fatty liver disease, we characterized Mboat7 liver-specific KO mice (Mboat7 LSKO). Chow-fed Mboat7 LSKO mice developed fatty livers and associated liver injury. Lipidomic analysis of liver using MS revealed a pronounced reduction in 20-carbon PUFA content in phosphatidylinositols (PIs) but not in other phospholipids. The change in fatty acid composition of PIs in these mice was associated with a marked increase in de novo lipogenesis because of activation of SREBP-1c, a transcription factor that coordinates the activation of genes encoding enzymes in the fatty acid biosynthesis pathway. Hepatic removal of both SREBP cleavage-activating protein (Scap) and Mboat7 normalized hepatic triglycerides relative to Scap-only hepatic KO, showing that increased SREBP-1c processing is required for Mboat7-induced steatosis. This study reveals a clear relationship between PI fatty acid composition and regulation of hepatic fat synthesis and delineates the mechanism by which mutations in MBOAT7 cause hepatic steatosis.
Collapse
Affiliation(s)
- Mingfeng Xia
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Preethi Chandrasekaran
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shunxing Rong
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaorong Fu
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matthew A Mitsche
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| |
Collapse
|
65
|
Dai XY, Zhu SY, Li MZ, Talukder M, Zhao Y, Li JL. Potential Role of Lycopene in the Inhibition of Di(2-ethylhexyl) Phthalate-Induced Ferroptosis in Spleen Via Modulation of Iron Ion Homeostasis. ACS Pharmacol Transl Sci 2021; 4:386-395. [PMID: 33615188 DOI: 10.1021/acsptsci.1c00001] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Indexed: 02/08/2023]
Abstract
Di(2-ethylhexyl) phthalate (DEHP) is a synthetic chemical and widely used as a plasticizer. Humans can be exposed to DEHP through direct contact or environmental contamination. Lycopene (Lyc) has been discussed as a potential effector in the prevention and therapy of various diseases. 140 male mice were assigned into control, vehicle control, Lyc (5 mg/kg BW/d), DEHP (500 and 1000 mg/kg BW/d, respectively), and DEHP + Lyc groups and treated with an oral gavage that lasted 28 d. The ultrastructural results showed that DEHP induced pathological changes and mitochondrial injuries. We further revealed that DEHP exposure destroyed the Fe2+ imbalance homeostasis and, consequently, increases of lipid peroxidation and inhibition of cysteine/glutamate antiporter, all of which were involved in the process of ferroptsis. Moreover, the supplementation of Lyc significantly inhibited the ferroptsis changes mentioned above. Altogether, these results indicated that DEHP exposure triggered splenic cell death via ferroptosis; meanwhile, they also shed new evidence on a potential clue for the intervention and prevention of DEHP-related diseases.
Collapse
Affiliation(s)
- Xue-Yan Dai
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China
| | - Shi-Yong Zhu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China
| | - Mu-Zi Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China
| | - Milton Talukder
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China.,Department of Physiology and Pharmacology, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Barishal 8210, Bangladesh
| | - Yi Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China
| | - Jin-Long Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P. R. China.,Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin 150030, P. R. China.,Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin 150030, P. R. China
| |
Collapse
|
66
|
Quercetin Improving Lipid Metabolism by Regulating Lipid Metabolism Pathway of Ileum Mucosa in Broilers. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:8686248. [PMID: 33014279 PMCID: PMC7520004 DOI: 10.1155/2020/8686248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 02/06/2023]
Abstract
This study is aimed at evaluating the regulatory mechanism of quercetin on lipid metabolism in the ileum of broilers to better understand these pathways decreasing abdominal fat. 480 chickens were randomly divided into 4 groups (control, 0.02% quercetin, 0.04% quercetin, and 0.06% quercetin). Breast muscle, thigh muscle, and abdominal fat pad were removed and weighed at 42 d of age. Serum was obtained by centrifuging blood samples from the jugular vein (10 ml) to determine high-density lipoprotein (HDL), total cholesterol (TC), low-density lipoprotein (LDL), triglyceride (TG), leptin, and adiponectin using ELISA. About 5 g of the ileum was harvested and immediately frozen in liquid nitrogen for RNA-seq. Then, the confirmation of RNA-seq results by the Real-Time Quantitative PCR (RT-qPCR) method was evaluated using Pearson's correlation. Compared with control, abdominal fat percentage was significantly decreased with increasing quercetin supplementation, and the best result was obtained at 0.06% dietary quercetin supplementation (P < 0.01). Breast muscle percentage was significantly decreased at 0.02% quercetin (P < 0.01), and thigh muscle percentage tended to increase (P = 0.078). Meanwhile, 0.04% and 0.06% quercetin significantly decreased TG (P < 0.01), TC (P < 0.01), and LDL content (P < 0.05) in serum. Serum leptin and adiponectin contents were significantly increased by 0.04% and 0.06% dietary quercetin supplementation, compared with the control (P < 0.01). Analyses of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) database were used to identify differently expressed genes and lipid metabolism pathways. Quercetin decreased abdominal fat percentage through regulating fat digestion and absorption, glycerophospholipid metabolism, AMPK signaling pathway, fatty acid degradation, and cholesterol metabolism.
Collapse
|
67
|
Hishikawa D, Yanagida K, Nagata K, Kanatani A, Iizuka Y, Hamano F, Yasuda M, Okamura T, Shindou H, Shimizu T. Hepatic Levels of DHA-Containing Phospholipids Instruct SREBP1-Mediated Synthesis and Systemic Delivery of Polyunsaturated Fatty Acids. iScience 2020; 23:101495. [PMID: 32891885 PMCID: PMC7481256 DOI: 10.1016/j.isci.2020.101495] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/25/2020] [Accepted: 08/19/2020] [Indexed: 12/25/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and arachidonic acid (ARA), play fundamental roles in mammalian physiology. Although PUFA imbalance causes various disorders, mechanisms of the regulation of their systemic levels are poorly understood. Here, we report that hepatic DHA-containing phospholipids (DHA-PLs) determine the systemic levels of PUFAs through the SREBP1-mediated transcriptional program. We demonstrated that liver-specific deletion of Agpat3 leads to a decrease of DHA-PLs and a compensatory increase of ARA-PLs not only in the liver but also in other tissues including the brain. Together with recent findings that plasma lysophosphatidylcholine (lysoPC) is the major source of brain DHA, our results indicate that hepatic AGPAT3 contributes to brain DHA accumulation by supplying DHA-PLs as precursors of DHA-lysoPC. Furthermore, dietary fish oil-mediated suppression of hepatic PUFA biosynthetic program was blunted in liver-specific Agpat3 deletion. Our findings highlight the central role of hepatic DHA-PLs as the molecular rheostat for systemic homeostasis of PUFAs.
Collapse
Affiliation(s)
- Daisuke Hishikawa
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan.
| | - Keisuke Yanagida
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Katsuyuki Nagata
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Ayumi Kanatani
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Yoshiko Iizuka
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Fumie Hamano
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan; Life Science Core Faculty, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Megumi Yasuda
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Tadashi Okamura
- Laboratory Animal Medicine, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan; Section of Animal Models, Department of Infectious Diseases, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan; Department of Lipid Science, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takao Shimizu
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan; Department of Lipidomics, Graduate School of Medicine, the University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
| |
Collapse
|
68
|
Liu N, Sun Q, Xu H, Yu X, Chen W, Wei H, Jiang J, Xu Y, Lu W. Hyperuricemia induces lipid disturbances mediated by LPCAT3 upregulation in the liver. FASEB J 2020; 34:13474-13493. [PMID: 32780898 DOI: 10.1096/fj.202000950r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 07/18/2020] [Accepted: 07/24/2020] [Indexed: 12/18/2022]
Abstract
Potential underlying molecular mechanisms for uric acid-induced lipid metabolic disturbances had not been elucidated clearly. This study investigated the effects and underlying mechanisms of uric acid on the development of lipid metabolic disorders. We collected blood samples from 100 healthy people and 100 patients with hyperuricemia for whom serum lipid analysis was performed. Meanwhile, a mouse model of hyperuricemia was generated, and lipidomics was performed on liver tissues, comparing control and hyperuricemia groups, to analyze lipid profiles and key metabolic enzymes. Uric acid directly induced serum lipid metabolic disorders in both humans and mice based on triglycerides, total cholesterol, and low-density lipoprotein cholesterol. Through lipidomic analysis, 46 lipids were differentially expressed in hyperuricemic mouse livers, and the phosphatidylcholine composition was altered, which was mediated by LPCAT3 upregulation. High-uric acid levels-induced p-STAT3 inhibition and SREBP-1c activation in vivo and in vitro. Moreover, LPCAT3-knockdown significantly attenuated uric acid-induced p-STAT3 inhibition, SREBP-1c activation, and lipid metabolic disorders in L02 cells. In conclusion, uric acid induces lipid metabolic disturbances through LPCAT3-mediated p-STAT3 inhibition and SREBP-1c activation. LPCAT3 could be a key regulatory factor linking hyperuricemia and lipid metabolic disorders. These results might provide novel insights into the clinical treatment of hyperuricemia.
Collapse
Affiliation(s)
- Ning Liu
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Qianqian Sun
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Hu Xu
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Xiaojuan Yu
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Wentong Chen
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Hongquan Wei
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Jie Jiang
- Basic Medical College, Anhui Medical University, Hefei, China.,College of Pharmacy, Anhui Medical University, Hefei, China
| | - Youzhi Xu
- Basic Medical College, Anhui Medical University, Hefei, China
| | - Wenjie Lu
- Basic Medical College, Anhui Medical University, Hefei, China
| |
Collapse
|
69
|
Ruhanen H, Haridas PAN, Jauhiainen M, Olkkonen VM. Angiopoietin-like protein 3, an emerging cardiometabolic therapy target with systemic and cell-autonomous functions. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158791. [PMID: 32777482 DOI: 10.1016/j.bbalip.2020.158791] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/23/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Angiopoietin like protein 3 (ANGPTL3) is best known for its function as an inhibitor of lipoprotein and endothelial lipases. Due to the capacity of genetic or pharmacologic ANGPTL3 suppression to markedly reduce circulating lipoproteins, and the documented cardioprotection upon such suppression, ANGPTL3 has become an emerging therapy target for which both antibody and antisense oligonucleotide (ASO) therapeutics are being clinically tested. While the antibody is relatively selective for circulating ANGPTL3, the ASO also depletes the intra-hepatocellular protein, and there is emerging evidence for cell-autonomous functions of ANGPTL3 in the liver. These include regulation of hepatocyte glucose and fatty acid uptake, insulin sensitivity, LDL/VLDL remnant uptake, VLDL assembly/secretion, polyunsaturated fatty acid (PUFA) and PUFA-derived lipid mediator content, and gene expression. In this review we elaborate on (i) why ANGPTL3 is considered one of the most promising new cardiometabolic therapy targets, and (ii) the present evidences for its intra-hepatocellular or cell-autonomous functions.
Collapse
Affiliation(s)
- Hanna Ruhanen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Molecular and Integrative Biosciences, University of Helsinki, Finland
| | | | - Matti Jauhiainen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
| |
Collapse
|
70
|
The Lysophosphatidylserines-An Emerging Class of Signalling Lysophospholipids. J Membr Biol 2020; 253:381-397. [PMID: 32767057 DOI: 10.1007/s00232-020-00133-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/24/2020] [Indexed: 12/30/2022]
Abstract
Lysophospholipids are potent hormone-like signalling biological lipids that regulate many important biological processes in mammals (including humans). Lysophosphatidic acid and sphingosine-1-phosphate represent the best studied examples for this lipid class, and their metabolic enzymes and/or cognate receptors are currently under clinical investigation for treatment of various neurological and autoimmune diseases in humans. Over the past two decades, the lysophsophatidylserines (lyso-PSs) have emerged as yet another biologically important lysophospholipid, and deregulation in its metabolism has been linked to various human pathophysiological conditions. Despite its recent emergence, an exhaustive review summarizing recent advances on lyso-PSs and the biological pathways that this bioactive lysophospholipid regulates has been lacking. To address this, here, we summarize studies that led to the discovery of lyso-PS as a potent signalling biomolecule, and discuss the structure, its detection in biological systems, and the biodistribution of this lysophospholipid in various mammalian systems. Further, we describe in detail the enzymatic pathways that are involved in the biosynthesis and degradation of this lipid and the putative lyso-PS receptors reported in the literature. Finally, we discuss the various biological pathways directly regulated by lyso-PSs in mammals and prospect new questions for this still emerging biomedically important signalling lysophospholipid.
Collapse
|
71
|
Hsieh WY, Zhou QD, York AG, Williams KJ, Scumpia PO, Kronenberger EB, Hoi XP, Su B, Chi X, Bui VL, Khialeeva E, Kaplan A, Son YM, Divakaruni AS, Sun J, Smale ST, Flavell RA, Bensinger SJ. Toll-Like Receptors Induce Signal-Specific Reprogramming of the Macrophage Lipidome. Cell Metab 2020; 32:128-143.e5. [PMID: 32516576 PMCID: PMC7891175 DOI: 10.1016/j.cmet.2020.05.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/07/2020] [Accepted: 05/06/2020] [Indexed: 02/08/2023]
Abstract
Macrophages reprogram their lipid metabolism in response to activation signals. However, a systems-level understanding of how different pro-inflammatory stimuli reshape the macrophage lipidome is lacking. Here, we use complementary "shotgun" and isotope tracer mass spectrometry approaches to define the changes in lipid biosynthesis, import, and composition of macrophages induced by various Toll-like receptors (TLRs) and inflammatory cytokines. "Shotgun" lipidomics data revealed that different TLRs and cytokines induce macrophages to acquire distinct lipidomes, indicating their specificity in reshaping lipid composition. Mechanistic studies showed that differential reprogramming of lipid composition is mediated by the opposing effects of MyD88- and TRIF-interferon-signaling pathways. Finally, we applied these insights to show that perturbing reprogramming of lipid composition can enhance inflammation and promote host defense to bacterial challenge. These studies provide a framework for understanding how inflammatory stimuli reprogram lipid composition of macrophages while providing a knowledge platform to exploit differential lipidomics to influence immunity.
Collapse
Affiliation(s)
- Wei-Yuan Hsieh
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Quan D Zhou
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Autumn G York
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA; Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Kevin J Williams
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Philip O Scumpia
- Department of Medicine, Division of Dermatology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Eliza B Kronenberger
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Xen Ping Hoi
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Baolong Su
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Xun Chi
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Viet L Bui
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA; Division of Rheumatology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Elvira Khialeeva
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Amber Kaplan
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Young Min Son
- Department of Immunology, Mayo Clinic Alix School of Medicine, Rochester, MN 55905, USA; Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic Alix School of Medicine, Rochester, MN 55905, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Jie Sun
- Department of Immunology, Mayo Clinic Alix School of Medicine, Rochester, MN 55905, USA; Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic Alix School of Medicine, Rochester, MN 55905, USA
| | - Stephen T Smale
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Steven J Bensinger
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| |
Collapse
|
72
|
Meroni M, Longo M, Fracanzani AL, Dongiovanni P. MBOAT7 down-regulation by genetic and environmental factors predisposes to MAFLD. EBioMedicine 2020; 57:102866. [PMID: 32629394 PMCID: PMC7339032 DOI: 10.1016/j.ebiom.2020.102866] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 12/11/2022] Open
Abstract
Metabolic associated fatty liver disease (MAFLD) encompasses a broad spectrum of hepatic disorders, which include steatosis, nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis, that is a critical risk factor for hepatocellular carcinoma (HCC) development. Its pathogenesis is intertwined with obesity and type 2 diabetes (T2D). However, the predisposition to develop MAFLD is severely influenced by environmental and inherited cues. The rs641738 variant close to MBOAT7 gene has been identified by a genome-wide association screening in heavy drinkers. Although this variant has been associated with the entire spectrum of MAFLD, these results have not been completely replicated and the debate is still opened. Thus, functional studies that unravel the biological mechanisms underlying the genetic association with fatty liver are required. This review aims to summarize the clinical and experimental findings regarding the rs641738 variation and MBOAT7 function, with the purpose to shed light to its role as novel player in MAFLD pathophysiology.
Collapse
Affiliation(s)
- Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
| | - Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Anna L Fracanzani
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milano, Milan, Italy.
| |
Collapse
|
73
|
Harayama T, Shimizu T. Roles of polyunsaturated fatty acids, from mediators to membranes. J Lipid Res 2020; 61:1150-1160. [PMID: 32487545 PMCID: PMC7397749 DOI: 10.1194/jlr.r120000800] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/28/2020] [Indexed: 12/20/2022] Open
Abstract
PUFAs, such as AA and DHA, are recognized as important biomolecules, but understanding their precise roles and modes of action remains challenging. PUFAs are precursors for a plethora of signaling lipids, for which knowledge about synthetic pathways and receptors has accumulated. However, due to their extreme diversity and the ambiguity concerning the identity of their cognate receptors, the roles of PUFA-derived signaling lipids require more investigation. In addition, PUFA functions cannot be explained just as lipid mediator precursors because they are also critical for the regulation of membrane biophysical properties. The presence of PUFAs in membrane lipids also affects the functions of transmembrane proteins and peripheral membrane proteins. Although the roles of PUFAs as membrane lipid building blocks were difficult to analyze, the discovery of lysophospholipid acyltransferases (LPLATs), which are critical for their incorporation, advanced our understanding. Recent studies unveiled how LPLATs affect PUFA levels in membrane lipids, and their genetic manipulation became an excellent strategy to study the roles of PUFA-containing lipids. In this review, we will provide an overview of metabolic pathways regulating PUFAs as lipid mediator precursors and membrane components and update recent progress about their functions. Some issues to be solved for future research will also be discussed.
Collapse
Affiliation(s)
- Takeshi Harayama
- Department of Biochemistry and National Centre of Competence in Research in Chemical Biology, University of Geneva, CH-1211 Geneva, Switzerland
| | - Takao Shimizu
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan and Department of Lipidomics, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|
74
|
Age-Related Changes in Hair Shaft Protein Profiling and Genetically Variant Peptides. Forensic Sci Int Genet 2020; 47:102309. [PMID: 32485593 DOI: 10.1016/j.fsigen.2020.102309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/07/2020] [Accepted: 05/10/2020] [Indexed: 01/01/2023]
Abstract
Recent reports highlight possible improvements in individual identification using proteomic information from human hair evidence. These reports have stimulated investigation of parameters that affect the utility of proteomic information. In addition to variables already studied relating to processing technique and anatomic origin of hair shafts, an important variable is hair ageing. Present work focuses on the effect of age on protein profiling and analysis of genetically variant peptides (GVPs). Hair protein profiles may be affected by developmental and physiological changes with age of the donor, exposure to different environmental conditions and intrinsic processes, including during storage. First, to explore whether general trends were evident in the population at different ages, hair samples were analyzed from groups of different subjects in their 20's, 40's and 60's. No significant differences were seen as a function of age, but consistent differences were evident between European American and African American hair profiles. Second, samples collected from single individuals at different ages were analyzed. Mostly, these showed few protein expression level differences over periods of 10 years or less, but samples from subjects at 44 and 65 year intervals were distinctly different in profile. The results indicate that use of protein profiling for personal identification, if practical, would be limited to decadal time intervals. Moreover, batch effects were clearly evident in samples processed by different staff. To investigate the contribution of storage (at room temperature) in affecting the outcomes, the same proteomic digests were analyzed for GVPs. In samples stored over 10 years, GVPs were reduced in number in parallel with the yield of identified proteins and unique peptides. However, a very different picture emerged with respect to personal identification. Numbers of GVPs sufficed to distinguish individuals despite the age differences of the samples. As a practical matter, three hair samples per person provided nearly the maximal number obtained from 5 or 6 samples. The random match probability (where the log increased in proportion to the number of GVPs) reached as high as 1 in 108. The data indicate that GVP results are dependent on the single nucleotide polymorphism profile of the donor genome, where environmental/processing factors affect only the yield, and thus are consistent despite the ages of the donors and samples and batchwise effects in processing. This conclusion is critical for application to casework where the samples may be in storage for long periods and used to match samples recently collected.
Collapse
|
75
|
Ichu TA, Reed A, Ogasawara D, Ulanovskaya O, Roberts A, Aguirre CA, Bar-Peled L, Gao J, Germain J, Barbas S, Masuda K, Conti B, Tontonoz P, Cravatt BF. ABHD12 and LPCAT3 Interplay Regulates a Lyso-phosphatidylserine-C20:4 Phosphatidylserine Lipid Network Implicated in Neurological Disease. Biochemistry 2020; 59:1793-1799. [PMID: 32364701 DOI: 10.1021/acs.biochem.0c00292] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PHARC (polyneuropathy, hearing loss, cerebellar ataxia, retinitis pigmentosa, and cataract) is a human neurological disorder caused by deleterious mutations in the ABHD12 gene, which encodes an integral membrane lyso-phosphatidylserine (lyso-PS) lipase. Pharmacological or genetic disruption of ABHD12 leads to higher levels of lyso-PS lipids in human cells and the central nervous system (CNS) of mice. ABHD12 loss also causes rapid rewiring of PS content, resulting in selective increases in the level of arachidonoyl (C20:4) PS and decreases in the levels of other PS species. The biochemical basis for ABHD12-dependent PS remodeling and its pathophysiological significance remain unknown. Here, we show that genetic deletion of the lysophospholipid acyltransferase LPCAT3 blocks accumulation of brain C20:4 PS in mice lacking ABHD12 and concurrently produces hyper-increases in the level of lyso-PS in these animals. These lipid changes correlate with exacerbated auditory dysfunction and brain microgliosis in mice lacking both ABHD12 and LPCAT3. Taken together, our findings reveal that ABHD12 and LPCAT3 coordinately regulate lyso-PS and C20:4 PS content in the CNS and point to lyso-PS lipids as the likely bioactive metabolites contributing to PHARC-related neuropathologies.
Collapse
Affiliation(s)
- Taka-Aki Ichu
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Alex Reed
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Daisuke Ogasawara
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | | | - Amanda Roberts
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Carlos A Aguirre
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Liron Bar-Peled
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Jie Gao
- Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, California 90024, United States
| | - Jason Germain
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Sabrina Barbas
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Kim Masuda
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Bruno Conti
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Peter Tontonoz
- Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, California 90024, United States
| | - Benjamin F Cravatt
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| |
Collapse
|
76
|
Matilainen J, Mustonen AM, Rilla K, Käkelä R, Sihvo SP, Nieminen P. Orotic acid-treated hepatocellular carcinoma cells resist steatosis by modification of fatty acid metabolism. Lipids Health Dis 2020; 19:70. [PMID: 32284043 PMCID: PMC7155272 DOI: 10.1186/s12944-020-01243-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/18/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Orotic acid (OA) has been intensively utilized to induce fatty liver in rats. Although the capacity of OA to cause steatosis is species-specific, previous in vitro studies indicate that humans could also be susceptible to OA-induced fatty liver. The aim of the present study was to re-elucidate the potential of OA exposure to modulate the cellular mechanisms involved in both non-alcoholic fatty liver disease pathogenesis and cellular protection from lipid accumulation. In addition, alterations in detailed fatty acid (FA) profiles of cells and culture media were analyzed to assess the significance of lipid metabolism in these phenomena. METHODS In our experiments, human hepatocellular carcinoma HepG2 cells were exposed to OA. Bacterial endotoxin, lipopolysaccharide (LPS), was used to mimic hepatic inflammation. The lipogenic and inflammatory effects of OA and/or LPS on cells were assessed by labeling cellular lipids with Nile red stain and by performing image quantifications. The expression levels of key enzymes involved in de novo lipogenesis (DNL) and of inflammatory markers related to the disease development were studied by qRT-PCR. FA profiles of cells and culture media were determined from total lipids with gas chromatography-mass spectrometry. RESULTS Our data indicate that although OA possibly promotes the first stage of DNL, it does not cause a definite lipogenic transformation in HepG2 cells. Reduced proportions of 16:0, increased stearoyl-Coenzyme A desaturase 1 mRNA expression and relatively high proportions of 16:1n-7 suggest that active delta9-desaturation may limit lipogenesis and the accumulation of toxic 16:0. Inflammatory signaling could be reduced by the increased production of long-chain n-3 polyunsaturated FA (PUFA) and the active incorporation of certain FA, including 18:1n-9, into cells. In addition, increased proportions of 20:4n-6 and 22:6n-3, total PUFA and dimethyl acetal 18:0 suggest that OA exposure may cause increased secretion of lipoproteins and extracellular vesicles. CONCLUSIONS The present data suggest that, apart from the transcription-level events reported by previous studies, modifications of FA metabolism may also be involved in the prevention of OA-mediated steatosis. Increased delta9-desaturation and secretion of lipoproteins and extracellular vesicles could offer potential mechanisms for further studies to unravel how OA-treated cells alleviate lipidosis.
Collapse
Affiliation(s)
- Johanna Matilainen
- Faculty of Health Sciences, School of Medicine, Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.
| | - Anne-Mari Mustonen
- Faculty of Health Sciences, School of Medicine, Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
- Faculty of Science and Forestry, Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101, Joensuu, Finland
| | - Kirsi Rilla
- Faculty of Health Sciences, School of Medicine, Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Reijo Käkelä
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Programme, University of Helsinki, P.O. Box 65, FI-00014, Helsinki, Finland
- Helsinki Institute for Life Science (HiLIFE), Helsinki University Lipidomics Unit (HiLIPID), University of Helsinki, P.O. Box 65, FI-00014, Helsinki, Finland
| | - Sanna P Sihvo
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Programme, University of Helsinki, P.O. Box 65, FI-00014, Helsinki, Finland
- Helsinki Institute for Life Science (HiLIFE), Helsinki University Lipidomics Unit (HiLIPID), University of Helsinki, P.O. Box 65, FI-00014, Helsinki, Finland
| | - Petteri Nieminen
- Faculty of Health Sciences, School of Medicine, Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| |
Collapse
|
77
|
Abstract
Nonalcoholic fatty liver disease is strongly associated with obesity and the metabolic syndrome, but genetic factors also contribute to disease susceptibility. Human genetic studies have identified several common genetic variants contributing to nonalcoholic fatty liver disease initiation and progression. These findings have provided new insights into the pathogenesis of nonalcoholic fatty liver disease and opened up new avenues for the development of therapeutic interventions. In this review, we summarize the current state of knowledge about the genetic determinants of nonalcoholic fatty liver disease, focusing on the most robustly validated genetic risk factors and on recently discovered modifiers of disease progression.
Collapse
Affiliation(s)
- Julia Kozlitina
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8591, USA.
| |
Collapse
|
78
|
Regulation of intestinal lipid metabolism: current concepts and relevance to disease. Nat Rev Gastroenterol Hepatol 2020; 17:169-183. [PMID: 32015520 DOI: 10.1038/s41575-019-0250-7] [Citation(s) in RCA: 223] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/02/2019] [Indexed: 12/21/2022]
Abstract
Lipids entering the gastrointestinal tract include dietary lipids (triacylglycerols, cholesteryl esters and phospholipids) and endogenous lipids from bile (phospholipids and cholesterol) and from shed intestinal epithelial cells (enterocytes). Here, we comprehensively review the digestion, uptake and intracellular re-synthesis of intestinal lipids as well as their packaging into pre-chylomicrons in the endoplasmic reticulum, their modification in the Golgi apparatus and the exocytosis of the chylomicrons into the lamina propria and subsequently to lymph. We also discuss other fates of intestinal lipids, including intestinal HDL and VLDL secretion, cytosolic lipid droplets and fatty acid oxidation. In addition, we highlight the applicability of these findings to human disease and the development of therapeutics targeting lipid metabolism. Finally, we explore the emerging role of the gut microbiota in modulating intestinal lipid metabolism and outline key questions for future research.
Collapse
|
79
|
Meroni M, Dongiovanni P, Longo M, Carli F, Baselli G, Rametta R, Pelusi S, Badiali S, Maggioni M, Gaggini M, Fracanzani AL, Romeo S, Gatti S, Davidson NO, Gastaldelli A, Valenti L. Mboat7 down-regulation by hyper-insulinemia induces fat accumulation in hepatocytes. EBioMedicine 2020; 52:102658. [PMID: 32058943 PMCID: PMC7026742 DOI: 10.1016/j.ebiom.2020.102658] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/16/2022] Open
Abstract
Background Naturally occurring variation in Membrane-bound O-acyltransferase domain-containing 7 (MBOAT7), encoding for an enzyme involved in phosphatidylinositol acyl-chain remodelling, has been associated with fatty liver and hepatic disorders. Here, we examined the relationship between hepatic Mboat7 down-regulation and fat accumulation. Methods Hepatic MBOAT7 expression was surveyed in 119 obese individuals and in experimental models. MBOAT7 was acutely silenced by antisense oligonucleotides in C57Bl/6 mice, and by CRISPR/Cas9 in HepG2 hepatocytes. Findings In obese individuals, hepatic MBOAT7 mRNA decreased from normal liver to steatohepatitis, independently of diabetes, inflammation and MBOAT7 genotype. Hepatic MBOAT7 levels were reduced in murine models of fatty liver, and by hyper-insulinemia. In wild-type mice, Mboat7 was down-regulated by refeeding and insulin, concomitantly with insulin signalling activation. Acute hepatic Mboat7 silencing promoted hepatic steatosis in vivo and enhanced expression of fatty acid transporter Fatp1. MBOAT7 deletion in hepatocytes reduced the incorporation of arachidonic acid into phosphatidylinositol, consistently with decreased enzymatic activity, determining the accumulation of saturated triglycerides, enhanced lipogenesis and FATP1 expression, while FATP1 deletion rescued the phenotype. Interpretation MBOAT7 down-regulation by hyper-insulinemia contributes to hepatic fat accumulation, impairing phosphatidylinositol remodelling and up-regulating FATP1. Funding LV was supported by MyFirst Grant AIRC n.16888, Ricerca Finalizzata Ministero della Salute RF-2016–02,364,358, Ricerca corrente Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico; LV and AG received funding from the European Union Programme Horizon 2020 (No. 777,377) for the project LITMUS-“Liver Investigation: Testing Marker Utility in Steatohepatitis”. MM was supported by Fondazione Italiana per lo Studio del Fegato (AISF) ‘Mario Coppo’ fellowship.
Collapse
Affiliation(s)
- Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Ospedale Policlinico via F Sforza 35, 20122 Milano, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
| | - Fabrizia Carli
- National Research Council (CNR), Institute of Clinical Physiology, Pisa, Italy
| | - Guido Baselli
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Ospedale Policlinico via F Sforza 35, 20122 Milano, Italy
| | - Raffaela Rametta
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Serena Pelusi
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Ospedale Policlinico via F Sforza 35, 20122 Milano, Italy; Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Italy
| | - Sara Badiali
- Department of Surgery, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Marco Maggioni
- Department of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Melania Gaggini
- National Research Council (CNR), Institute of Clinical Physiology, Pisa, Italy
| | - Anna Ludovica Fracanzani
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Ospedale Policlinico via F Sforza 35, 20122 Milano, Italy
| | - Stefano Romeo
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden; Cardiology Department, Sahlgrenska University Hospital, Gothenburg, Sweden; Clinical Nutrition Department of Medical and Surgical Science, University Magna Graecia, Catanzaro, Italy
| | - Stefano Gatti
- Preclinical research center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Nicholas O Davidson
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, Italy
| | - Amalia Gastaldelli
- National Research Council (CNR), Institute of Clinical Physiology, Pisa, Italy
| | - Luca Valenti
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Ospedale Policlinico via F Sforza 35, 20122 Milano, Italy; Translational Medicine, Department of Transfusion Medicine and Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Italy.
| |
Collapse
|
80
|
Valentine WJ, Hashidate-Yoshida T, Yamamoto S, Shindou H. Biosynthetic Enzymes of Membrane Glycerophospholipid Diversity as Therapeutic Targets for Drug Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1274:5-27. [PMID: 32894505 DOI: 10.1007/978-3-030-50621-6_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Biophysical properties of membranes are dependent on their glycerophospholipid compositions. Lysophospholipid acyltransferases (LPLATs) selectively incorporate fatty chains into lysophospholipids to affect the fatty acid composition of membrane glycerophospholipids. Lysophosphatidic acid acyltransferases (LPAATs) of the 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) family incorporate fatty chains into phosphatidic acid during the de novo glycerophospholipid synthesis in the Kennedy pathway. Other LPLATs of both the AGPAT and the membrane bound O-acyltransferase (MBOAT) families further modify the fatty chain compositions of membrane glycerophospholipids in the remodeling pathway known as the Lands' cycle. The LPLATs functioning in these pathways possess unique characteristics in terms of their biochemical activities, regulation of expressions, and functions in various biological contexts. Essential physiological functions for LPLATs have been revealed in studies using gene-deficient mice, and important roles for several enzymes are also indicated in human diseases where their mutation or dysregulation causes or contributes to the pathological condition. Now several LPLATs are emerging as attractive therapeutic targets, and further understanding of the mechanisms underlying their physiological and pathological roles will aid in the development of novel therapies to treat several diseases that involve altered glycerophospholipid metabolism.
Collapse
Affiliation(s)
- William J Valentine
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan. .,Department of Molecular Therapy, National Center of Neurology and Psychiatry, Tokyo, Japan.
| | | | - Shota Yamamoto
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan. .,Department of Lipid Science, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. .,Japan Agency for Medical Research and Development, Tokyo, Japan.
| |
Collapse
|
81
|
Jalil A, Bourgeois T, Ménégaut L, Lagrost L, Thomas C, Masson D. Revisiting the Role of LXRs in PUFA Metabolism and Phospholipid Homeostasis. Int J Mol Sci 2019; 20:ijms20153787. [PMID: 31382500 PMCID: PMC6696407 DOI: 10.3390/ijms20153787] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 01/19/2023] Open
Abstract
Liver X receptors (LXRs) play a pivotal role in fatty acid (FA) metabolism. So far, the lipogenic consequences of in vivo LXR activation, as characterized by a major hepatic steatosis, has constituted a limitation to the clinical development of pharmacological LXR agonists. However, recent studies provided a different perspective. Beyond the quantitative accumulation of FA, it appears that LXRs induce qualitative changes in the FA profile and in the distribution of FAs among cellular lipid species. Thus, LXRs activate the production of polyunsaturated fatty acids (PUFAs) and their distribution into phospholipids via the control of FA desaturases, FA elongases, lysophosphatidylcholine acyltransferase (LPCAT3), and phospholipid transfer protein (PLTP). Therefore, LXRs control, in a dynamic manner, the PUFA composition and the physicochemical properties of cell membranes as well as the release of PUFA-derived lipid mediators. Recent studies suggest that modulation of PUFA and phospholipid metabolism by LXRs are involved in the control of lipogenesis and lipoprotein secretion by the liver. In myeloid cells, the interplay between LXR and PUFA metabolism affects the inflammatory response. Revisiting the complex role of LXRs in FA metabolism may open new opportunities for the development of LXR modulators in the field of cardiometabolic diseases.
Collapse
Affiliation(s)
- Antoine Jalil
- Université Bourgogne Franche-Comté, LNC UMR1231, F-21000 Dijon, France
- INSERM, LNC UMR 1231, F-21000 Dijon, France
- FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000 Dijon, France
| | - Thibaut Bourgeois
- Université Bourgogne Franche-Comté, LNC UMR1231, F-21000 Dijon, France
- INSERM, LNC UMR 1231, F-21000 Dijon, France
- FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000 Dijon, France
| | - Louise Ménégaut
- Université Bourgogne Franche-Comté, LNC UMR1231, F-21000 Dijon, France
- INSERM, LNC UMR 1231, F-21000 Dijon, France
- FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000 Dijon, France
| | - Laurent Lagrost
- Université Bourgogne Franche-Comté, LNC UMR1231, F-21000 Dijon, France
- INSERM, LNC UMR 1231, F-21000 Dijon, France
- FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000 Dijon, France
| | - Charles Thomas
- Université Bourgogne Franche-Comté, LNC UMR1231, F-21000 Dijon, France
- INSERM, LNC UMR 1231, F-21000 Dijon, France
- FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000 Dijon, France
| | - David Masson
- Université Bourgogne Franche-Comté, LNC UMR1231, F-21000 Dijon, France.
- INSERM, LNC UMR 1231, F-21000 Dijon, France.
- FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000 Dijon, France.
| |
Collapse
|
82
|
Kita Y, Shindou H, Shimizu T. Cytosolic phospholipase A2 and lysophospholipid acyltransferases. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:838-845. [DOI: 10.1016/j.bbalip.2018.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 01/01/2023]
|
83
|
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.
Collapse
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
| |
Collapse
|
84
|
Seessle J, Liebisch G, Schmitz G, Stremmel W, Chamulitrat W. Compositional Changes Among Triglycerides and Phospholipids During FATP4 Sensitization with Palmitate Lead to ER Stress in Cultured Cells. EUR J LIPID SCI TECH 2019. [DOI: 10.1002/ejlt.201800394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jessica Seessle
- Department of Internal Medicine IVGastroenterology and Infectious DiseaseIm Neuenheimer Feld 41069120HeidelbergGermany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory MedicineUniversity of RegensburgFranz‐Josef‐Strauss‐Allee 1193053RegensburgGermany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory MedicineUniversity of RegensburgFranz‐Josef‐Strauss‐Allee 1193053RegensburgGermany
| | - Wolfgang Stremmel
- Department of Internal Medicine IVGastroenterology and Infectious DiseaseIm Neuenheimer Feld 41069120HeidelbergGermany
| | - Walee Chamulitrat
- Department of Internal Medicine IVGastroenterology and Infectious DiseaseIm Neuenheimer Feld 41069120HeidelbergGermany
| |
Collapse
|
85
|
Nilsson Å, Duan RD. Pancreatic and mucosal enzymes in choline phospholipid digestion. Am J Physiol Gastrointest Liver Physiol 2019; 316:G425-G445. [PMID: 30576217 DOI: 10.1152/ajpgi.00320.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The digestion of choline phospholipids is important for choline homeostasis, lipid signaling, postprandial lipid and energy metabolism, and interaction with intestinal bacteria. The digestion is mediated by the combined action of pancreatic and mucosal enzymes. In the proximal small intestine, hydrolysis of phosphatidylcholine (PC) to 1-lyso-PC and free fatty acid (FFA) by the pancreatic phospholipase A2 IB coincides with the digestion of the dietary triacylglycerols by lipases, but part of the PC digestion is extended and must be mediated by other enzymes as the jejunoileal brush-border phospholipase B/lipase and mucosal secreted phospholipase A2 X. Absorbed 1-lyso-PC is partitioned in the mucosal cells between degradation and reacylation into chyle PC. Reutilization of choline for hepatic bile PC synthesis, and the reacylation of 1-lyso-PC into chylomicron PC by the lyso-PC-acyl-CoA-acyltransferase 3 are important features of choline recycling and postprandial lipid metabolism. The role of mucosal enzymes is emphasized by sphingomyelin (SM) being sequentially hydrolyzed by brush-border alkaline sphingomyelinase (alk-SMase) and neutral ceramidase to sphingosine and FFA, which are well absorbed. Ceramide and sphingosine-1-phosphate are generated and are both metabolic intermediates and important lipid messengers. Alk-SMase has anti-inflammatory effects that counteract gut inflammation and tumorigenesis. These may be mediated by multiple mechanisms including generation of sphingolipid metabolites and suppression of autotaxin induction and lyso-phosphatidic acid formation. Here we summarize current knowledge on the roles of pancreatic and mucosal enzymes in PC and SM digestion, and its implications in intestinal and liver diseases, bacterial choline metabolism in the gut, and cholesterol absorption.
Collapse
Affiliation(s)
- Åke Nilsson
- Department of Clow-linical Sciences Lund, Division of Medicine, Gastroenterology, Lund University , Lund , Sweden
| | - Rui-Dong Duan
- Gastroenterology and Nutrition Laboratory, Department of Clinical Sciences, Lund University , Lund , Sweden
| |
Collapse
|
86
|
Kawana H, Kano K, Shindou H, Inoue A, Shimizu T, Aoki J. An accurate and versatile method for determining the acyl group-introducing position of lysophospholipid acyltransferases. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1053-1060. [PMID: 30853650 DOI: 10.1016/j.bbalip.2019.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/02/2019] [Accepted: 02/24/2019] [Indexed: 10/27/2022]
Abstract
Lysophospholipid acyltransferases (LPLATs) incorporate a fatty acid into the hydroxyl group of lysophospholipids (LPLs) and are critical for determining the fatty acid composition of phospholipids. Previous studies have focused mainly on their molecular identification and their substrate specificity regarding the polar head groups and acyl-CoAs. However, little is known about the positional specificity of the hydroxyl group of the glycerol backbone (sn-2 or sn-1) at which LPLATs introduce a fatty acid. This is mainly due to the instability of LPLs used as an acceptor, especially for LPLs with a fatty acid at the sn-2 position of the glycerol backbone (sn-2-LPLs), which are essential for the enzymatic assay to determine the positional specificity. In this study, we established a method to determine the positional specificity of LPLAT by preparing stable sn-2-LPLs in combination with PLA2 digestion, and applied the method for determining the positional specificity of several LPLATs including LPCAT1, LYCAT and LPCAT3. We found that LPCAT1 introduced palmitic acid both at the sn-1 and sn-2 positions of palmitoyl-LPC, while LYCAT and LPCAT3 specifically introduced stearic acid at the sn-1 position of LPG and arachidonic acid at the sn-2 position of LPC, respectively. The present method for evaluating the positional specificity could also be used for biochemical characterization of other LPLATs.
Collapse
Affiliation(s)
- Hiroki Kawana
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-Ku, Sendai 980-8578, Japan; AMED-LEAP, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Kuniyuki Kano
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-Ku, Sendai 980-8578, Japan; AMED-LEAP, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Hideo Shindou
- Department of Lipid Signaling, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo 162-8655, Japan; AMED-CREST, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Asuka Inoue
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-Ku, Sendai 980-8578, Japan; AMED-LEAP, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Takao Shimizu
- AMED-CREST, Chiyoda-ku, Tokyo 100-0004, Japan; Departments of Lipidomics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Junken Aoki
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-Ku, Sendai 980-8578, Japan; AMED-LEAP, Chiyoda-ku, Tokyo 100-0004, Japan.
| |
Collapse
|
87
|
Royo F, Gil-Carton D, Gonzalez E, Mleczko J, Palomo L, Perez-Cormenzana M, Mayo R, Alonso C, Falcon-Perez JM. Differences in the metabolite composition and mechanical properties of extracellular vesicles secreted by hepatic cellular models. J Extracell Vesicles 2019; 8:1575678. [PMID: 30788084 PMCID: PMC6374943 DOI: 10.1080/20013078.2019.1575678] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/19/2018] [Accepted: 01/18/2019] [Indexed: 01/09/2023] Open
Abstract
Liver constitutes the major metabolic factory in the organism and is involved in the synthesis, secretion and clearance of many blood-circulating molecules. Previously, we have characterised the protein and RNA cargo of extracellular vesicles (EVs) secreted by two hepatic cellular models, a mouse hepatocyte progenitor cell line (MLP29) and primary rat hepatocytes (RHs). Here, we report the metabolome profile of these vesicles by performing a targeted UHPLC-MS metabolomics analysis of these two cellular models and their respective secreted EVs. Visual inspection of the data through principal component analysis allows clear separation of the metabolic profile of cells and EVs, and also of both cellular models. Correlation matrix supported that lipid composition of EVs is mainly determined by parent cell composition. EVs derived from MLP29 and RHs showed a negative correlation in their percentage composition of ceramides, glycerophospholipids, sphingomyelins and triglycerides. Metabolites enriched in EVs were also different depending on the cellular model. EVs secreted by MLP29 were enriched in different species of sphingomyelins and ceramides underrepresented in EVs secreted by RHs. Remarkably, triglycerides constitute an important percentage of the composition of EVs derived from RHs. We further investigate if the differences in lipid composition were also accompanied by differences in mechanical behaviour, by using atomic force microscopy complemented with nanoindentation-based methodology. To compare the stiffness and brittleness of EVs derived from MLP29 cell line and RH primary cells, FZ curves were performed in the centre of single vesicles and the differences found in their force-vs.-indentation curves suggest that RHs EVs are softer (less stiff) and less resistance to mechanical failure than MLP29 EVs. Therefore, we can conclude that EVs from different origin carry a characteristic lipid composition related to their parental cell composition, and exhibit different mechanical properties. Abbreviations: For the identification of the different species of lipids, the following abbreviations has been employed: Cer, ceramide; ChoE, Cholesteryl Ester; CMH, monohexosylceramide; DAG, diglycerid; LPC, lysophosphatidylcholin; LPI, lysophosphatidyinositol; PC, phosphocoline; PE, phoethanolamine; PI, phosphoinositol; SM, sphingomyelin; TAG, triglycerid
Collapse
Affiliation(s)
- Felix Royo
- Exosomes Laboratory, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Spain
| | - David Gil-Carton
- Electron Microscopy Technology Platform, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain
| | | | - Justyna Mleczko
- Exosomes Laboratory, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain
| | - Laura Palomo
- Exosomes Laboratory, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain
| | | | - Rebeca Mayo
- OWL Metabolomics, Bizkaia Technology Park, Derio, Spain
| | | | - Juan M Falcon-Perez
- Exosomes Laboratory, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Spain.,Metabolomics platform, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
88
|
Jiang H, Li Z, Huan C, Jiang XC. Macrophage Lysophosphatidylcholine Acyltransferase 3 Deficiency-Mediated Inflammation Is Not Sufficient to Induce Atherosclerosis in a Mouse Model. Front Cardiovasc Med 2019; 5:192. [PMID: 30705887 PMCID: PMC6344406 DOI: 10.3389/fcvm.2018.00192] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/17/2018] [Indexed: 12/19/2022] Open
Abstract
Mammalian cell membrane phosphatidylcholines (PCs), the major phospholipids, exhibit diversity which is controlled by Lands' cycle or PC remodeling pathway. Lysophosphatidylcholine acyltransferase (LPCAT) is one of the major players in the pathway and plays an important role in maintaining cell membrane structure and function. LPCAT3 is highly expressed in macrophages, however, its role in mediating inflammation is still not understood, since contradictory results were reported previously. The order of LPCAT mRNA levels in mouse macrophages is as follows: LPCAT3 > LPCAT1 > LPCAT2 >> LPCAT4. In order to investigate the role of LPCAT3 in macrophages, we prepared myeloid cell-specific Lpcat3 knockout (KO) mice and found that the deficiency significantly reduced certain polyunsaturated phosphatidylcholines, such as 16:0/20:4, 18:1/18:2, 18:0/20:4, and 18:1/20:4 in macrophage plasma membrane. Lpcat3 deficiency significantly increased toll like receptor 4 protein and phosphorylated c-Src in membrane lipid rafts, and increased LPS-induced IL-6 and TNFα releasing through activation of MAP kinases and NFκB. Moreover, the ablation of LPCAT3 in macrophages significantly increase of M1 macrophages. However, macrophage deletion of Lpcat3 in (LDL receptor) Ldlr KO mice, both male and female, on a Western type diet, did not have a significant impact on atherogenesis. In conclusion, LPCAT3 is one of LPCATs in macrophages, involved in PC remodeling. LPCAT3 deficiency has no effect on cholesterol efflux. However, the deficiency promotes macrophage inflammatory response, but such an effect has a marginal influence on the development of atherosclerosis.
Collapse
Affiliation(s)
- Hui Jiang
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Molecular and Cellular Cardiology Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
| | - Zhiqiang Li
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Molecular and Cellular Cardiology Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
| | - Chongmin Huan
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Molecular and Cellular Cardiology Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States.,Department of Surgery, State University of New York Downstate Medical Center, Brooklyn, NY, United States
| | - Xian-Cheng Jiang
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, United States.,Molecular and Cellular Cardiology Program, VA New York Harbor Healthcare System, Brooklyn, NY, United States
| |
Collapse
|
89
|
van der Veen JN, Lingrell S, McCloskey N, LeBlond ND, Galleguillos D, Zhao YY, Curtis JM, Sipione S, Fullerton MD, Vance DE, Jacobs RL. A role for phosphatidylcholine and phosphatidylethanolamine in hepatic insulin signaling. FASEB J 2019; 33:5045-5057. [PMID: 30615497 DOI: 10.1096/fj.201802117r] [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] [Indexed: 02/06/2023]
Abstract
Phosphatidylethanolamine N-methyltransferase (PEMT) is an important enzyme in hepatic phosphatidylcholine (PC) biosynthesis. Pemt-/- mice fed a high-fat diet are protected from obesity and whole-body insulin resistance. However, Pemt-/- mice develop severe nonalcoholic steatohepatitis (NASH). Because NASH is often associated with hepatic insulin resistance, we investigated whether the increased insulin sensitivity in Pemt-/- mice was restricted to nonhepatic tissues or whether the liver was also insulin sensitive. Strikingly, the livers of Pemt-/- mice compared with those of Pemt+/+ mice were not insulin resistant, despite elevated levels of hepatic triacylglycerols and diacylglycerols, as well as increased hepatic inflammation and fibrosis. Endogenous glucose production was lower in Pemt-/- mice under both basal and hyperinsulinemic conditions. Experiments in primary hepatocytes and hepatoma cells revealed improved insulin signaling in the absence of PEMT, which was not due to changes in diacylglycerols, ceramides, or gangliosides. On the other hand, the phospholipid composition in hepatocytes seems critically important for insulin signaling such that lowering the PC:phosphatidylethanolamine (PE) ratio improves insulin signaling. Thus, treatments to reduce the PC:PE ratio in liver may protect against the development of hepatic insulin resistance.-Van der Veen, J. N., Lingrell, S., McCloskey, N., LeBlond, N. D., Galleguillos, D., Zhao, Y. Y., Curtis, J. M., Sipione, S., Fullerton, M. D., Vance, D. E., Jacobs, R. L. A role for phosphatidylcholine and phosphatidylethanolamine in hepatic insulin signaling.
Collapse
Affiliation(s)
- Jelske N van der Veen
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Susanne Lingrell
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nicholas McCloskey
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicholas D LeBlond
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Danny Galleguillos
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada; and
| | - Yuan Y Zhao
- Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Jonathan M Curtis
- Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Simonetta Sipione
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada; and
| | - Morgan D Fullerton
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Dennis E Vance
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
90
|
Zhang P, Csaki LS, Ronquillo E, Baufeld LJ, Lin JY, Gutierrez A, Dwyer JR, Brindley DN, Fong LG, Tontonoz P, Young SG, Reue K. Lipin 2/3 phosphatidic acid phosphatases maintain phospholipid homeostasis to regulate chylomicron synthesis. J Clin Invest 2018; 129:281-295. [PMID: 30507612 DOI: 10.1172/jci122595] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/09/2018] [Indexed: 12/31/2022] Open
Abstract
The lipin phosphatidic acid phosphatase (PAP) enzymes are required for triacylglycerol (TAG) synthesis from glycerol 3-phosphate in most mammalian tissues. The 3 lipin proteins (lipin 1, lipin 2, and lipin 3) each have PAP activity, but have distinct tissue distributions, with lipin 1 being the predominant PAP enzyme in many metabolic tissues. One exception is the small intestine, which is unique in expressing exclusively lipin 2 and lipin 3. TAG synthesis in small intestinal enterocytes utilizes 2-monoacylglycerol and does not require the PAP reaction, making the role of lipin proteins in enterocytes unclear. Enterocyte TAGs are stored transiently as cytosolic lipid droplets or incorporated into lipoproteins (chylomicrons) for secretion. We determined that lipin enzymes are critical for chylomicron biogenesis, through regulation of membrane phospholipid composition and association of apolipoprotein B48 with nascent chylomicron particles. Lipin 2/3 deficiency caused phosphatidic acid accumulation and mammalian target of rapamycin complex 1 (mTORC1) activation, which were associated with enhanced protein levels of a key phospholipid biosynthetic enzyme (CTP:phosphocholine cytidylyltransferase α) and altered membrane phospholipid composition. Impaired chylomicron synthesis in lipin 2/3 deficiency could be rescued by normalizing phospholipid synthesis levels. These data implicate lipin 2/3 as a control point for enterocyte phospholipid homeostasis and chylomicron biogenesis.
Collapse
Affiliation(s)
- Peixiang Zhang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Lauren S Csaki
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Emilio Ronquillo
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Lynn J Baufeld
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jason Y Lin
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Alexis Gutierrez
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jennifer R Dwyer
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David N Brindley
- Signal Transduction Research Group, Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Loren G Fong
- Department of Medicine, Division of Cardiology, and
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
| | - Stephen G Young
- Department of Medicine, Division of Cardiology, and.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
| |
Collapse
|
91
|
Tang CH, Lin CY, Tsai YL, Lee SH, Wang WH. Lipidomics as a diagnostic tool of the metabolic and physiological state of managed whales: A correlation study of systemic metabolism. Zoo Biol 2018; 37:440-451. [PMID: 30457161 DOI: 10.1002/zoo.21452] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/09/2018] [Accepted: 10/09/2018] [Indexed: 11/06/2022]
Abstract
Integrating multifactor blood analysis is a key step toward a precise diagnosis of the health status of marine mammals. Variations in the circulating lipid profile reflect changes in the metabolism and physiology of an individual. To demonstrate the practicability of lipid profiling for physiological assessment, the phosphorylcholine-containing lipids in the plasma of long-term managed beluga whales (Delphinapterus leucas) were profiled using a lipidomics methodology. Using a multivariate analysis, the mean corpuscular volume, cholesterol, potassium, and γ-glutamyltranspeptidase levels were well modeled with the lipid profile of the female whales. In the models, the correlated lipids provided information about blood parameter-related metabolism and physiological regulation, in particular relating to cholesterol and inflammation. In the males, the levels of cholesterol, triglycerides, blood urea nitrogen, creatinine, plasma iron, and segmented neutrophil were well modeled with the lipid profile. In addition to providing information about the related metabolism and regulation, through a cross-linked analysis of the blood parameters, the correlated lipids indicated a parallel regulation involved in the energy metabolism of the male whales. Lipidomics as a method for revealing the context of physiological change shows practical potential for the health care of managed whales.
Collapse
Affiliation(s)
- Chuan-Ho Tang
- Department of Biology, National Museum of Marine Biology and Aquarium, Pingtung, Taiwan.,Institute of Marine Biology, National Dong Hwa University, Pingtung, Taiwan
| | - Ching-Yu Lin
- Institute of Environmental Health, National Taiwan University, Taipei City, Taiwan
| | - Yi-Lun Tsai
- Department of Veterinary Medicine and Animal Hospital, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shu-Hui Lee
- Central of General Education, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Wei-Hsien Wang
- Department of Biology, National Museum of Marine Biology and Aquarium, Pingtung, Taiwan.,Department of Marine Biotechnology and Resources and Asia-Pacific Ocean Research Center, National Sun Yat-Sen University, Kaohsiung, Taiwan
| |
Collapse
|
92
|
Xiao C, Stahel P, Lewis GF. Regulation of Chylomicron Secretion: Focus on Post-Assembly Mechanisms. Cell Mol Gastroenterol Hepatol 2018; 7:487-501. [PMID: 30819663 PMCID: PMC6396431 DOI: 10.1016/j.jcmgh.2018.10.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/23/2018] [Accepted: 10/25/2018] [Indexed: 02/06/2023]
Abstract
Rapid and efficient digestion and absorption of dietary triglycerides and other lipids by the intestine, the packaging of those lipids into lipoprotein chylomicron (CM) particles, and their secretion via the lymphatic duct into the blood circulation are essential in maintaining whole-body lipid and energy homeostasis. Biosynthesis and assembly of CMs in enterocytes is a complex multistep process that is subject to regulation by intracellular signaling pathways as well as by hormones, nutrients, and neural factors extrinsic to the enterocyte. Dysregulation of this process has implications for health and disease, contributing to dyslipidemia and a potentially increased risk of atherosclerotic cardiovascular disease. There is increasing recognition that, besides intracellular regulation of CM assembly and secretion, regulation of postassembly pathways also plays important roles in CM secretion. This review examines recent advances in our understanding of the regulation of CM secretion in relation to mobilization of intestinal lipid stores, drawing particular attention to post-assembly regulatory mechanisms, including intracellular trafficking of triglycerides in enterocytes, CM mobilization from the lamina propria, and regulated transport of CM by intestinal lymphatics.
Collapse
Affiliation(s)
- Changting Xiao
- Changting Xiao, PhD, Princess Margaret Cancer Research Tower 10-203, Medical and Related Science Centre, 101 College Street, Toronto, Ontario M5G 1L7, Canada. fax: (416) 581-7487.
| | | | - Gary F. Lewis
- Correspondence Address correspondence to: Gary F. Lewis, MD, FRCPC, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada. fax: (416) 340-3314.
| |
Collapse
|
93
|
Abstract
Phospholipids are major constituents of biological membranes. The fatty acyl chain composition of phospholipids determines the biophysical properties of membranes and thereby affects their impact on biological processes. The composition of fatty acyl chains is also actively regulated through a deacylation and reacylation pathway called Lands' cycle. Recent studies of mouse genetic models have demonstrated that lysophosphatidylcholine acyltransferases (LPCATs), which catalyze the incorporation of fatty acyl chains into the sn-2 site of phosphatidylcholine, play important roles in pathophysiology. Two LPCAT family members, LPCAT1 and LPCAT3, have been particularly well studied. LPCAT1 is crucial for proper lung function due to its role in pulmonary surfactant biosynthesis. LPCAT3 maintains systemic lipid homeostasis by regulating lipid absorption in intestine, lipoprotein secretion, and de novo lipogenesis in liver. Mounting evidence also suggests that changes in LPCAT activity may be potentially involved in pathological conditions, including nonalcoholic fatty liver disease, atherosclerosis, viral infections, and cancer. Pharmacological manipulation of LPCAT activity and membrane phospholipid composition may provide new therapeutic options for these conditions.
Collapse
Affiliation(s)
- Bo Wang
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90272, USA;
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90272, USA;
| |
Collapse
|
94
|
Lee J, Ridgway ND. Phosphatidylcholine synthesis regulates triglyceride storage and chylomicron secretion by Caco2 cells. J Lipid Res 2018; 59:1940-1950. [PMID: 30115754 DOI: 10.1194/jlr.m087635] [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] [Received: 06/19/2018] [Revised: 08/09/2018] [Indexed: 11/20/2022] Open
Abstract
Intracellular lipid droplets (LDs) supply fatty acids for energy, membrane biogenesis, and lipoprotein secretion. The surface monolayer of LDs is composed of phospholipids, primarily phosphatidylcholine (PC), that stabilize the neutral lipid core of triglyceride (TG). To determine the relationship between PC synthesis and TG storage and secretion in chylomicrons, we used a model of intestinal-derived human epithelial colorectal adenocarcinoma (Caco2) cells with knockout of PCYT1A, which encodes the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT)α in the CDP-choline pathway, that were treated with the fatty acid oleate. CRISPR/Cas9 knockout of CCTα in Caco2 cells (Caco2-KO cells) reduced PC synthesis by 50%. Compared with Caco2 cells, Caco2-KO cells exposed to oleate had fewer and larger LDs and greater TG accumulation as a result. The addition of exogenous lysophosphatidylcholine to Caco2-KO cells reversed the LD morphology defect. Caco2-KO cells, differentiated into epithelial monolayers, accumulated intracellular TG and had deficient TG and chylomicron-associated apoB48 secretion; apoB100 secretion was unaffected by CCTα knockout or oleate. Metabolic-labeling and LD imaging of Caco2-KO cells indicated preferential shuttling of de novo synthesized TG into larger LDs rather than into chylomicrons. Thus, reduced de novo PC synthesis in Caco2 cells enhances TG storage in large LDs and inhibits apoB48 chylomicron secretion.
Collapse
Affiliation(s)
- Jonghwa Lee
- Atlantic Research Center, Departments of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Neale D Ridgway
- Atlantic Research Center, Departments of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| |
Collapse
|
95
|
Chan JP, Wong BH, Chin CF, Galam DLA, Foo JC, Wong LC, Ghosh S, Wenk MR, Cazenave-Gassiot A, Silver DL. The lysolipid transporter Mfsd2a regulates lipogenesis in the developing brain. PLoS Biol 2018; 16:e2006443. [PMID: 30074985 PMCID: PMC6093704 DOI: 10.1371/journal.pbio.2006443] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/15/2018] [Accepted: 07/11/2018] [Indexed: 01/12/2023] Open
Abstract
Brain development requires a massive increase in brain lipogenesis and accretion of the essential omega-3 fatty acid docosahexaenoic acid (DHA). Brain acquisition of DHA is primarily mediated by the transporter Major Facilitator Superfamily Domain containing 2a (Mfsd2a) expressed in the endothelium of the blood-brain barrier (BBB) and other abundant cell types within the brain. Mfsd2a transports DHA and other polyunsaturated fatty acids (PUFAs) esterified to lysophosphatidylcholine (LPC-DHA). However, the function of Mfsd2a and DHA in brain development is incompletely understood. Here, we demonstrate, using vascular endothelial-specific and inducible vascular endothelial-specific deletion of Mfsd2a in mice, that Mfsd2a is uniquely required postnatally at the BBB for normal brain growth and DHA accretion, with DHA deficiency preceding the onset of microcephaly. In Mfsd2a-deficient mouse models, a lipidomic signature was identified that is indicative of increased de novo lipogenesis of PUFAs. Gene expression profiling analysis of these DHA-deficient brains indicated that sterol regulatory-element binding protein (Srebp)-1 and Srebp-2 pathways were highly elevated. Mechanistically, LPC-DHA treatment of primary neural stem cells down-regulated Srebp processing and activation in a Mfsd2a-dependent fashion, resulting in profound effects on phospholipid membrane saturation. In addition, Srebp regulated the expression of Mfsd2a. These data identify LPC-DHA transported by Mfsd2a as a physiological regulator of membrane phospholipid saturation acting in a feedback loop on Srebp activity during brain development. The brain is the most lipid-rich organ in the body. Brain development involves a tremendous increase in the synthesis and accretion of fatty acids. De novo synthesis of fatty acids is mediated by Srebp transcription factors, whereas acquisition of essential fatty acids via uptake of plasma-derived lysophosphatidylcholine containing the essential omega-3 fatty acid docosahexaenoic acid (LPC-DHA) is mediated by the transporter Mfsd2a in the cells that line the blood vessels in the brain. The function of Mfsd2a and DHA in brain development is incompletely understood. Our study determined that Mfsd2a is required at the blood-brain barrier for brain development and accretion of DHA after birth in mice. Moreover, we determined that a major function of DHA in the brain is to negatively regulate Srebp activation, resulting in profound effects on membrane phospholipid composition. These findings reveal that LPC-DHA transported by Mfsd2a plays a physiological role in both brain growth and in maintaining plasma membrane phospholipid composition during brain development.
Collapse
Affiliation(s)
- Jia Pei Chan
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Bernice H. Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Cheen Fei Chin
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Dwight L. A. Galam
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Juat Chin Foo
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Loo Chin Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Sujoy Ghosh
- Centre for Computational Biology, Duke-NUS Medical School, Singapore, Singapore
| | - Markus R. Wenk
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | | | - David L. Silver
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
- * E-mail:
| |
Collapse
|
96
|
Abstract
Liver X receptors α and β (LXRα and LXRβ) are nuclear receptors with pivotal roles in the transcriptional control of lipid metabolism. Transcriptional activity of LXRs is induced in response to elevated cellular levels of cholesterol. LXRs bind to and regulate the expression of genes that encode proteins involved in cholesterol absorption, transport, efflux, excretion and conversion to bile acids. The coordinated, tissue-specific actions of the LXR pathway maintain systemic cholesterol homeostasis and regulate immune and inflammatory responses. LXRs also regulate fatty acid metabolism by controlling the lipogenic transcription factor sterol regulatory element-binding protein 1c and regulate genes that encode proteins involved in fatty acid elongation and desaturation. LXRs exert important effects on the metabolism of phospholipids, which, along with cholesterol, are major constituents of cellular membranes. LXR activation preferentially drives the incorporation of polyunsaturated fatty acids into phospholipids by inducing transcription of the remodelling enzyme lysophosphatidylcholine acyltransferase 3. The ability of the LXR pathway to couple cellular sterol levels with the saturation of fatty acids in membrane phospholipids has implications for several physiological processes, including lipoprotein production, dietary lipid absorption and intestinal stem cell proliferation. Understanding how LXRs regulate membrane composition and function might provide new therapeutic insight into diseases associated with dysregulated lipid metabolism, including atherosclerosis, diabetes mellitus and cancer.
Collapse
Affiliation(s)
- Bo Wang
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
| |
Collapse
|
97
|
Tran M, Liu Y, Huang W, Wang L. Nuclear receptors and liver disease: Summary of the 2017 basic research symposium. Hepatol Commun 2018; 2:765-777. [PMID: 30129636 PMCID: PMC6049066 DOI: 10.1002/hep4.1203] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/03/2018] [Accepted: 05/10/2018] [Indexed: 12/11/2022] Open
Abstract
The nuclear receptor superfamily contains important transcriptional regulators that play pleiotropic roles in cell differentiation, development, proliferation, and metabolic processes to govern liver physiology and pathology. Many nuclear receptors are ligand-activated transcription factors that regulate the expression of their target genes by modulating transcriptional activities and epigenetic changes. Additionally, the protein complex associated with nuclear receptors consists of a multitude of coregulators, corepressors, and noncoding RNAs. Therefore, acquiring new information on nuclear receptors may provide invaluable insight into novel therapies and shed light on new interventions to reduce the burden and incidence of liver diseases. (Hepatology Communications 2018;2:765-777).
Collapse
Affiliation(s)
- Melanie Tran
- Department of Physiology and Neurobiology and Institute for Systems Genomics, University of Connecticut, Storrs, CT
| | - Yanjun Liu
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute City of Hope National Medical Center Duarte CA
| | - Wendong Huang
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute City of Hope National Medical Center Duarte CA
| | - Li Wang
- Department of Physiology and Neurobiology and Institute for Systems Genomics, University of Connecticut, Storrs, CT.,Veterans Affairs Connecticut Healthcare System West Haven CT.,Department of Internal Medicine, Section of Digestive Diseases Yale University New Haven CT
| |
Collapse
|
98
|
Thomas C, Jalil A, Magnani C, Ishibashi M, Queré R, Bourgeois T, Bergas V, Ménégaut L, Patoli D, Le Guern N, Labbé J, Gautier T, de Barros JPP, Lagrost L, Masson D. LPCAT3 deficiency in hematopoietic cells alters cholesterol and phospholipid homeostasis and promotes atherosclerosis. Atherosclerosis 2018; 275:409-418. [PMID: 29866392 DOI: 10.1016/j.atherosclerosis.2018.05.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/04/2018] [Accepted: 05/16/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND AIMS LPCAT3 plays a major role in phospholipid metabolism in the liver and intestine. However, the impact of LPCAT3 on hematopoietic cell and macrophage functions has yet to be described. Our aim was to understand the functions of LPCAT3 in macrophages and to investigate whether LPCAT3 deficiency in hematopoietic cells may affect atherosclerosis development. METHODS Mice with constitutive Lpcat3 deficiency (Lpcat3-/-) were generated. We used fetal hematopoietic liver cells to generate WT and Lpcat3-/- macrophages in vitro and to perform hematopoietic cell transplantation in recipient Ldlr-/- mice. RESULTS Lpcat3-deficient macrophages displayed major reductions in the arachidonate content of phosphatidylcholines, phosphatidylethanolamines and, unexpectedly, plasmalogens. These changes were associated with altered cholesterol homeostasis, including an increase in the ratio of free to esterified cholesterol and a reduction in cholesterol efflux in Lpcat3-/- macrophages. This correlated with the inhibition of some LXR-regulated pathways, related to altered cellular availability of the arachidonic acid. Indeed, LPCAT3 deficiency was associated with decreased Abca1, Abcg1 and ApoE mRNA levels in fetal liver cells derived macrophages. In vivo, these changes translated into a significant increase in atherosclerotic lesions in Ldlr-/- mice with hematopoietic LPCAT3 deficiency. CONCLUSIONS This study identifies LPCAT3 as a key factor in the control of phospholipid homeostasis and arachidonate availability in myeloid cells and underlines a new role for LPCAT3 in plasmalogen metabolism. Moreover, our work strengthens the link between phospholipid and sterol metabolism in hematopoietic cells, with significant consequences on nuclear receptor-regulated pathways and atherosclerosis development.
Collapse
Affiliation(s)
- Charles Thomas
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Antoine Jalil
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Charlène Magnani
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Minako Ishibashi
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Ronan Queré
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Thibaut Bourgeois
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Victoria Bergas
- Lipidomic analytic plate-forme, UBFC, Batiment B3, Bvd Maréchal de Lattre de Tassigny, 21000, Dijon, France
| | - Louise Ménégaut
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France; CHU Dijon, laboratoire de Biochimie, F-21000, Dijon, France
| | - Danish Patoli
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Naig Le Guern
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Jérôme Labbé
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Thomas Gautier
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France
| | - Jean Paul Pais de Barros
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France; Lipidomic analytic plate-forme, UBFC, Batiment B3, Bvd Maréchal de Lattre de Tassigny, 21000, Dijon, France
| | - Laurent Lagrost
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France; CHU Dijon, laboratoire de Biochimie, F-21000, Dijon, France
| | - David Masson
- Univ. Bourgogne Franche-Comté, LNC UMR1231, F-21000, Dijon, France; INSERM, LNC UMR 1231, F-21000, Dijon, France; FCS Bourgogne-Franche Comté, LipSTIC LabEx, F-21000, Dijon, France; CHU Dijon, laboratoire de Biochimie, F-21000, Dijon, France.
| |
Collapse
|
99
|
Lysophosphatidylcholine acyltransferase 3 deficiency impairs 3T3L1 cell adipogenesis through activating Wnt/β-catenin pathway. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:834-843. [PMID: 29673706 DOI: 10.1016/j.bbalip.2018.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 04/07/2018] [Accepted: 04/15/2018] [Indexed: 11/21/2022]
Abstract
Levels of polyunsaturated phosphatidylcholine (PC) influence plasma membrane structure and function. Phosphatidylcholine (PC) is synthesized de novo in the Kennedy pathway and then undergoes extensive deacylation/reacylation remodeling via Lands' cycle (non-Kennedy pathway). The reacylation is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT), which adds a polyunsaturated fatty acid at the sn-2 position. Four LPCAT isoforms have been described to date, among which we found LPCAT3 to be the major isoform in adipose tissue, but its exact role in adipogenesis is unclear. In this study, we aimed to investigate whether LPCAT3 activity affects 3T3L1 cell adipogenic differentiation potential and its underline mechanism. Lentivirus-mediated LPCAT3 shRNA expression stably knocked down LPCAT3 in 3T3L1 preadipocytes and LPCAT3 deficiency dramatically reduced the levels of cellular polyunsaturated PCs. Importantly, we found that this deficiency activated the β-catenin dependent Wnt signaling pathway, which suppressed the expression of adipogenesis-related genes, thereby inhibiting 3T3L1 preadipocyte differentiation and lipid accumulation. Moreover, three different Wnt/β-catenin pathway inhibitors reversed the effect of LPCAP3 deficiency, suggesting that Wnt/β-catenin pathway activation is one of the causes for the observed phenotypes. To the best of our knowledge, we show here for the first time that PC remodeling is an important regulator of adipocyte differentiation.
Collapse
|
100
|
Kalsbeek A, Veenstra J, Westra J, Disselkoen C, Koch K, McKenzie KA, O’Bott J, Vander Woude J, Fischer K, Shearer GC, Harris WS, Tintle NL. A genome-wide association study of red-blood cell fatty acids and ratios incorporating dietary covariates: Framingham Heart Study Offspring Cohort. PLoS One 2018; 13:e0194882. [PMID: 29652918 PMCID: PMC5898718 DOI: 10.1371/journal.pone.0194882] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 03/12/2018] [Indexed: 02/07/2023] Open
Abstract
Recent analyses have suggested a strong heritable component to circulating fatty acid (FA) levels; however, only a limited number of genes have been identified which associate with FA levels. In order to expand upon a previous genome wide association study done on participants in the Framingham Heart Study Offspring Cohort and FA levels, we used data from 2,400 of these individuals for whom red blood cell FA profiles, dietary information and genotypes are available, and then conducted a genome-wide evaluation of potential genetic variants associated with 22 FAs and 15 FA ratios, after adjusting for relevant dietary covariates. Our analysis found nine previously identified loci associated with FA levels (FADS, ELOVL2, PCOLCE2, LPCAT3, AGPAT4, NTAN1/PDXDC1, PKD2L1, HBS1L/MYB and RAB3GAP1/MCM6), while identifying four novel loci. The latter include an association between variants in CALN1 (Chromosome 7) and eicosapentaenoic acid (EPA), DHRS4L2 (Chromosome 14) and a FA ratio measuring delta-9-desaturase activity, as well as two loci associated with less well understood proteins. Thus, the inclusion of dietary covariates had a modest impact, helping to uncover four additional loci. While genome-wide association studies continue to uncover additional genes associated with circulating FA levels, much of the heritable risk is yet to be explained, suggesting the potential role of rare genetic variation, epistasis and gene-environment interactions on FA levels as well. Further studies are needed to continue to understand the complex genetic picture of FA metabolism and synthesis.
Collapse
Affiliation(s)
- Anya Kalsbeek
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
| | - Jenna Veenstra
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
| | - Jason Westra
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
| | - Craig Disselkoen
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
| | - Kristin Koch
- Department of Statistics, Baylor University, Waco, TX, United States of America
| | - Katelyn A. McKenzie
- Department of Statistics, Duke University, Durham, NC, United States of America
| | - Jacob O’Bott
- Department of Mathematics and Statistics, University of Maryland- Baltimore County, Baltimore, MD, United States of America
| | - Jason Vander Woude
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
| | - Karen Fischer
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
| | - Greg C. Shearer
- Department of Nutritional Sciences, Penn State University, State College, PA, United States of America
| | | | - Nathan L. Tintle
- Department of Mathematics, Statistics and Computer Science, Dordt College, Sioux Center, Iowa, United States of America
- * E-mail:
| |
Collapse
|