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Hyder A, Sheta B, Eissa M, Schrezenmeir J. Silencing the FABP3 gene in insulin-secreting cells reduces fatty acid uptake and protects against lipotoxicity. Acta Diabetol 2024:10.1007/s00592-024-02325-x. [PMID: 38960943 DOI: 10.1007/s00592-024-02325-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 06/18/2024] [Indexed: 07/05/2024]
Abstract
BACKGROUND Long-term exposure of pancreatic islets to fatty acids (FAs), common in obesity, metabolic syndrome, and type 2 diabetes, leads to a compensatory hyperactivity followed by inflammation, apoptosis, dysfunctional beta cells, and results in insulin dependence of the patient. Restriction of fatty uptake by islet beta cells may protect them from lipotoxicity. PURPOSE Pancreatic islet beta cells express the fatty acid binding protein 3 (FABP3) to bind FAs and to orchestrate lipid signals. Based on this, we investigated whether downregulation of FABP3, by Fabp3 silencing, might slow lipid metabolism and protect against lipotoxicity in insulin-secreting cells. RESULTS Neither Fabp3 silencing, nor overexpression affected the glucose-stimulated insulin secretion in absence of FAs. Fabp3 silencing decreased FA-uptake, lipid droplets formation, and the expression of the lipid accumulation-regulating gene Dgat1 in Ins1E cells. It reduced FA-induced inflammation by deactivation of NF-κB, which was associated with upregulation of IκBα and deactivation of the NF-κB p65 nuclear translocation, and the downregulation of the cytokines ILl-6, IL-1β, and TNFα. Ins1E cells were protected from the FA-induced apoptosis as assessed by different parameters including DNA degradation and cleaved caspase-3 immunoblotting. Furthermore, FABP3 silencing improved the viability, Pdx1 gene expression, and the insulin-secreting function in cells long-term cultured with palmitic acid. All results were confirmed by the opposite action rendered by FABP3 overexpression. CONCLUSION The present data reveals that pancreatic beta cells can be protected from lipotoxicity by inhibition of FA-uptake, intracellular utilization and accumulation. FABP3 inhibition, hence, may be a useful pharmaceutical approach in obesity, metabolic syndrome, and type 2 diabetes.
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Affiliation(s)
- Ayman Hyder
- Faculty of Science, Damietta University, New Damietta, 34517, Egypt.
| | - Basma Sheta
- Faculty of Science, Damietta University, New Damietta, 34517, Egypt
| | - Manar Eissa
- Faculty of Science, Damietta University, New Damietta, 34517, Egypt
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Drake RR, Louey S, Thornburg KL. Maturation of lipid metabolism in the fetal and newborn sheep heart. Am J Physiol Regul Integr Comp Physiol 2023; 325:R809-R819. [PMID: 37867472 PMCID: PMC11178298 DOI: 10.1152/ajpregu.00122.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/24/2023]
Abstract
At birth, the fetus experiences a dramatic change in environment that is accompanied by a shift in myocardial fuel preference from lactate and glucose in fetal life to fatty acid oxidation after birth. We hypothesized that fatty acid metabolic machinery would mature during fetal life in preparation for this extreme metabolic transformation at birth. We quantified the pre- (94-day and 135-day gestation, term ∼147 days) and postnatal (5 ± 4 days postnatal) gene expression and protein levels for fatty acid transporters and enzymes in hearts from a precocial species, the sheep. Gene expression of fatty acid translocase (CD36), acyl-CoA synthetase long-chain 1 (ACSL1), carnitine palmitoyltransferase 1 (CPT1), hydroxy-acyl dehydrogenase (HADH), acetyl-CoA acetyltransferase (ACAT1), isocitrate dehydrogenase (IDH), and glycerol phosphate acyltransferase (GPAT) progressively increased through the perinatal period, whereas several genes [fatty acid transport protein 6 (FATP6), acyl-CoA synthetase long chain 3 (ACSL3), long-chain acyl-CoA dehydrogenase (LCAD), very long-chain acyl-CoA dehydrogenase (VLCAD), pyruvate dehydrogenase kinase (PDK4), phosphatidic acid phosphatase (PAP), and diacylglycerol acyltransferase (DGAT)] were stable in fetal hearts and had high expression after birth. Protein expression of CD36 and ACSL1 progressively increased throughout the perinatal period, whereas protein expression of carnitine palmitoyltransferase 1a (fetal isoform) (CPT1a) decreased and carnitine palmitoyltransferase 1b (adult isoform) (CPT1b) remained constitutively expressed. Using fluorescent-tagged long-chain fatty acids (BODIPY-C12), we demonstrated that fetal (125 ± 1 days gestation) cardiomyocytes produce 59% larger lipid droplets (P < 0.05) compared with newborn (8 ± 1 day) cardiomyocytes. These results provide novel insights into the perinatal maturation of cardiac fatty acid metabolism in a precocial species.NEW & NOTEWORTHY This study characterized the previously unknown expression patterns of genes that regulate the metabolism of free fatty acids in the perinatal sheep myocardium. This study shows that the prenatal myocardium prepares for the dramatic switch from carbohydrate metabolism to near complete reliance on free fatty acids postnatally. Fetal and neonatal cardiomyocytes also demonstrate differing lipid storage mechanisms where fetal cardiomyocytes form larger lipid droplets compared with newborn cardiomyocytes.
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Affiliation(s)
- Rachel R Drake
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon, United States
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Kent L Thornburg
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon, United States
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Rodrigues C, Ismael S, Castela I, Barreiros-Mota I, Almeida MJ, Santos GM, Calhau C, Rocha JC, Faria A, Araújo JR. Trimethylamine increases intestinal fatty acid absorption: in vitro studies in a Caco-2 cell culture system. J Nutr Sci 2023; 12:e108. [PMID: 37964979 PMCID: PMC10641700 DOI: 10.1017/jns.2023.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/11/2023] [Accepted: 10/06/2023] [Indexed: 11/16/2023] Open
Abstract
Although elevated blood levels of trimethylamine N-oxide (TMAO) have been associated with atherosclerosis development in humans, the role of its gut microbiota-derived precursor, TMA, in this process has not been yet deciphered. Taking this into account, and the fact that increased intestinal fatty acid absorption contributes to atherosclerosis onset and progression, this study aimed to evaluate the effect of TMA on fatty acid absorption in a cell line that mimics human enterocytes. Caco-2 cells were treated with TMA 250 μM for 24 h. Fatty acid absorption was assessed by measuring the apical-to-basolateral transport and the intracellular levels of BODIPY-C12, a fluorescently labelled fatty acid analogue. Gene expression of the main intestinal fatty acid transporters was evaluated by real-time quantitative reverse transcription PCR. Compared to control conditions, TMA increased, in a time-dependent manner and by 20-50 %, the apical-to-basolateral transport and intracellular levels of BODIPY-C12 fatty acid in Caco-2 cells. Fatty acid transport protein 4 (FATP4) and fatty acid translocase (FAT)/CD36 gene expression were not stimulated by TMA, suggesting that TMA-induced increase in fatty acid transport may be mediated by an increase in FAT/CD36 and/or FATP4 activity and/or fatty acid passive transport. This study demonstrated that TMA increases the intestinal absorption of fatty acids. Future studies are necessary to confirm if this may constitute a novel mechanism that partially explains the existing positive association between the consumption of a diet rich in TMA sources (e.g. red meat) and the increased risk of atherosclerotic diseases.
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Key Words
- Caco-2 cells
- EDTA, ethylenediaminetetraacetic acid
- Enterocytes
- F, forward
- FABP, fatty acid-binding protein
- FABPpm, plasma membrane fatty acid-binding protein
- FAT/CD36, fatty acid translocase
- FATP4, fatty acid transport protein 4
- FBS, foetal bovine serum
- FSA, fluorescein sulphonic acid
- Fatty acid absorption
- HPRT, hypoxanthine guanine phosphoribosyltransferase
- MTT, 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide
- PBS, phosphate-buffered saline
- R, reverse
- TG, triacylglycerol
- TMA, trimethylamine
- TMAO, trimethylamine N-oxide
- Trimethylamine
- qRT-PCR, real-time quantitative reverse transcription polymerase chain reaction
- sem, standard error of the mean
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Affiliation(s)
- Catarina Rodrigues
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Shámila Ismael
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
- Nutrition & Metabolism, CINTESIS@RISE, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Inês Castela
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
- Nutrition & Metabolism, CINTESIS@RISE, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Inês Barreiros-Mota
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Maria João Almeida
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Gilberto Maia Santos
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Conceição Calhau
- Nutrition & Metabolism, CINTESIS@RISE, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
- Unidade Universitária Lifestyle Medicine José de Mello Saúde by NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Júlio César Rocha
- Nutrition & Metabolism, CINTESIS@RISE, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
- Reference Centre of Inherited Metabolic Diseases, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
| | - Ana Faria
- Nutrition & Metabolism, CHRC, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
- Nutrition & Metabolism, CINTESIS@RISE, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - João R. Araújo
- Nutrition & Metabolism, CINTESIS@RISE, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
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Hyder A. Naturally-occurring carboxylic acids from traditional antidiabetic plants as potential pancreatic islet FABP3 inhibitors. A molecular docking-aided study. Chem Biol Interact 2023; 372:110368. [PMID: 36709838 DOI: 10.1016/j.cbi.2023.110368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 01/18/2023] [Accepted: 01/25/2023] [Indexed: 01/27/2023]
Abstract
The antidiabetic action of traditional plants is mostly attributed to their antioxidant and anti-inflammatory properties. These plants are still having some secrets, making them an attractive source that allows for investigating new drugs or uncovering precise pharmacologic antidiabetic functions of their constituents. In diabetes, which is a lipid disease, long-term exposure of pancreatic islet beta cells to fatty acids (FAs) increases basal insulin release, reduces glucose-stimulated insulin secretion, causes islet beta cell inflammation, failure and apoptosis. Pancreatic islet beta cells express fatty acid binding protein 3 (FABP3) that receives long-chain FAs and traffics them throughout different cellular compartments to be metabolized and render their effects. Inhibition of this FABP3 may retard FA metabolism and protect islet beta cells. Since FAs interact with FABPs by their carboxylic group, some traditionally-known antidiabetic plants were reviewed in the present study, searching for their components that have common features of FABP ligands, namely carboxylic group and hydrophobic tail. Many of these carboxylic acids were computationally introduced into the ligand-binding pocket of FABP3 and some of them exhibited FABP3 ligand possibilities. Among others, the naturally occurring ferulic, cleomaldeic, caffeic, sinapic, hydroxycinnamic, 4-p-coumaroylquinic, quinoline-2-carboxylic, chlorogenic, 6-hydroxykynurenic, and rosmarinic acids in many plants are promising candidates for being FABP3-specific inhibitors. The study shed light on repurposing these phyto-carboxylic acids to function as FABP inhibitors. However, more in-depth biological and pharmacological studies to broaden the understanding of this function are needed.
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Affiliation(s)
- Ayman Hyder
- Faculty of Science, Damietta University, New Damietta 34517, Egypt.
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Disturbance of Fatty Acid Metabolism Promoted Vascular Endothelial Cell Senescence via Acetyl-CoA-Induced Protein Acetylation Modification. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1198607. [PMID: 35993026 PMCID: PMC9385365 DOI: 10.1155/2022/1198607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 06/27/2022] [Accepted: 07/01/2022] [Indexed: 11/18/2022]
Abstract
Endothelial cell senescence is the main risk factor contributing to vascular dysfunction and the progression of aging-related cardiovascular diseases. However, the relationship between endothelial cell metabolism and endothelial senescence remains unclear. The present study provides novel insight into fatty acid metabolism in the regulation of endothelial senescence. In the replicative senescence model and H2O2-induced premature senescence model of primary cultured human umbilical vein endothelial cells (HUVECs), fatty acid oxidation (FAO) was suppressed and fatty acid profile was disturbed, accompanied by downregulation of proteins associated with fatty acid uptake and mitochondrial entry, in particular the FAO rate-limiting enzyme carnitine palmitoyl transferase 1A (CPT1A). Impairment of fatty acid metabolism by silencing CPT1A or CPT1A inhibitor etomoxir facilitated the development of endothelial senescence, as implied by the increase of p53, p21, and senescence-associated β-galactosidase, as well as the decrease of EdU-positive proliferating cells. In the contrary, rescue of FAO by overexpression of CPT1A or supplement of short chain fatty acids (SCFAs) acetate and propionate ameliorated endothelial senescence. In vivo, treatment of acetate for 4 weeks lowered the blood pressure and alleviated the senescence-related phenotypes in aortas of Ang II-infused mice. Mechanistically, fatty acid metabolism regulates endothelial senescence via acetyl-coenzyme A (acetyl-CoA), as implied by the observations that suppression of acetyl-CoA production using the inhibitor of ATP citrate lyase NDI-091143 accelerated senescence of HUVECs and that supplementation of acetyl-CoA prevented H2O2-induced endothelial senescence. Deficiency of acetyl-CoA resulted in alteration of acetylated protein profiles which are associated with cell metabolism and cell cycle. These findings thus suggest that improvement of fatty acid metabolism might ameliorate endothelial senescence-associated cardiovascular diseases.
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Wang Y, Zhang X, Hu W, Dong C, Fu D, Habtegabir SG, Han Y. Ultra-fast screening of free fatty acids in human plasma using ion mobility mass spectrometry. J Sep Sci 2022; 45:1818-1826. [PMID: 35340115 DOI: 10.1002/jssc.202200037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/10/2022] [Accepted: 03/22/2022] [Indexed: 11/06/2022]
Abstract
Free fatty acids involved in many metabolic regulations in human body. In this work, an ultra-fast screening method was developed for the analysis of free fatty acids using trapped ion mobility spectrometry coupled with mass spectrometry. Thirty-three free fatty acids possessing different unsaturation degrees and different carbon chain lengths were baseline separated and characterized within milliseconds. Saturated, monounsaturated, and polyunsaturated free fatty acids showed different linearities between collision cross section values and m/z. Establishment of correlations between structures and collision cross section values provided additional qualitative information and made it possible to determine free fatty acids which were out of the standards pool but possessed the confirmed linearity. Gas-phase separation made the quantitative analysis reliable and repeatable at a much lower time cost than chromatographic methods. The sensitivity was comparable to and even better than the reported results. The method was validated and applied to profiling free fatty acids in human plasma. Saturated free fatty acids abundance in the fasting state was found to be lower than that in the postprandial state, while unsaturated species abundance was found higher. The method was fast and robust with minimum sample pretreatment, so it was promising in high-throughput screening of free fatty acids. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yinghao Wang
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Xianxie Zhang
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, 100005, China.,Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Wenya Hu
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Chenglong Dong
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Dali Fu
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Sara Girmay Habtegabir
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Yehua Han
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, China
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7
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Fatty acid transport protein 2 interacts with ceramide synthase 2 to promote ceramide synthesis. J Biol Chem 2022; 298:101735. [PMID: 35181339 PMCID: PMC8931434 DOI: 10.1016/j.jbc.2022.101735] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 01/15/2023] Open
Abstract
Dihydroceramide is a lipid molecule generated via the action of (dihydro)ceramide synthases (CerSs), which use two substrates, namely sphinganine and fatty acyl-CoAs. Sphinganine is generated via the sequential activity of two integral membrane proteins located in the endoplasmic reticulum. Less is known about the source of the fatty acyl-CoAs, although a number of cytosolic proteins in the pathways of acyl-CoA generation modulate ceramide synthesis via direct or indirect interaction with the CerSs. In this study, we demonstrate, by proteomic analysis of immunoprecipitated proteins, that fatty acid transporter protein 2 (FATP2) (also known as very long-chain acyl-CoA synthetase) directly interacts with CerS2 in mouse liver. Studies in cultured cells demonstrated that other members of the FATP family can also interact with CerS2, with the interaction dependent on both proteins being catalytically active. In addition, transfection of cells with FATP1, FATP2, or FATP4 increased ceramide levels although only FATP2 and 4 increased dihydroceramide levels, consistent with their known intracellular locations. Finally, we show that lipofermata, an FATP2 inhibitor which is believed to directly impact tumor cell growth via modulation of FATP2, decreased de novo dihydroceramide synthesis, suggesting that some of the proposed therapeutic effects of lipofermata may be mediated via (dihydro)ceramide rather than directly via acyl-CoA generation. In summary, our study reinforces the idea that manipulating the pathway of fatty acyl-CoA generation will impact a wide variety of down-stream lipids, not least the sphingolipids, which utilize two acyl-CoA moieties in the initial steps of their synthesis.
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Wu Y, Zhang N, Deng ZY, Zhang H, Li J. Effects of the Major Structured Triacylglycerols in Human Milk on Lipid Metabolism of Hepatocyte Cells in Vitro. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:9147-9156. [PMID: 33369388 DOI: 10.1021/acs.jafc.0c06976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The effect of structured triacylglycerols [1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL), 3-dilinoleoyl-2-palmitoylglycerol (LPL), and 1,3-dioleoyl-2-palmitoylglycerol (OPO)] in human milk on the lipid metabolism was unclear. Hence, this study investigated the effects of different structured triacylglycerols and their mixtures (M) (OPL/LPL/OPO in M1, M2, and M3 were 1.5:0.5:1, 1.2:1.2:1, and 0.5:0.2:1, respectively) on lipid and expression levels of some critical proteins involved in lipid metabolism in LO2 cells. Results showed that there was more lipid accumulation in the LO2 cells exposed to 2,3-dioleoyl-1-palmitoylglycerol (POO) than OPL, LPL, and OPO (p < 0.05), and more lipid accumulation was observed in the OPL group compared to LPL and OPO groups (p < 0.05). Moreover, there was more lipid accumulation in the M3 group compared to M1 and M2 groups. The expression level of diacylglycerol acyltransferase was highest in the POO group compared to LPL, OPO, and OPL groups and was higher in the M3 group than M1 and M2 groups. The expression levels of acetyl-CoA carboxylase 1 and long-chain acyl-CoA synthetase 1 were highest in the OPL group compared to OPO and LPL groups. In comparison to OPO and LPL, OPL seemed to be more likely to increase the content of triacylglycerols and cholesterol in LO2 cells; therefore, whether this was beneficial to the growth and development of infants needs further verification.
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Affiliation(s)
- Yanping Wu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
| | - Niu Zhang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
| | - Ze-Yuan Deng
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
| | - Hong Zhang
- Wilmar (Shanghai) Biotechnology Research & Development Center Company, Limited, Shanghai 200137, People's Republic of China
| | - Jing Li
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047, People's Republic of China
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Tetraspanin TM4SF5 in hepatocytes negatively modulates SLC27A transporters during acute fatty acid supply. Arch Biochem Biophys 2021; 710:109004. [PMID: 34364885 DOI: 10.1016/j.abb.2021.109004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022]
Abstract
Transmembrane 4 L six family member 5 (TM4SF5) is involved in nonalcoholic steatosis and further aggravation of liver disease. However, its mechanism for regulating FA accumulation is unknown. We investigated how TM4SF5 in hepatocytes affected FA accumulation during acute FA supply. TM4SF5-expressing hepatocytes and mouse livers accumulated less FAs, compared with those of TM4SF5 deficiency or inactivation. Binding of TM4SF5 to SLC27A2 increased gradually upon acute FA treatment, whereas TM4SF5 constitutively bound SLC27A5. Suppression of either SLC27A2 or SLC27A5 in hepatocytes expressing TM4SF5 differentially modulated initial and maximal FA uptake levels for a fast turnover of fatty acid. Altogether, TM4SF5 negatively modulates FA accumulation into hepatocytes via association with the transporters for an energy homeostasis, when FA are supplied acutely.
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Balakrishnan J, Kannan S, Govindasamy A. Structured form of DHA prevents neurodegenerative disorders: A better insight into the pathophysiology and the mechanism of DHA transport to the brain. Nutr Res 2020; 85:119-134. [PMID: 33482601 DOI: 10.1016/j.nutres.2020.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 12/16/2022]
Abstract
Docosahexaenoic acid (DHA) is one of the most important fatty acids that plays a critical role in maintaining proper brain function and cognitive development. Deficiency of DHA leads to several neurodegenerative disorders and, therefore, dietary supplementations of these fatty acids are essential to maintain cognitive health. However, the complete picture of how DHA is incorporated into the brain is yet to be explored. In general, the de novo synthesis of DHA is poor, and targeting the brain with specific phospholipid carriers provides novel insights into the process of reduction of disease progression. Recent studies have suggested that compared to triacylglycerol form of DHA, esterified form of DHA (i.e., lysophosphatidylcholine [lysoPC]) is better incorporated into the brain. Free DHA is transported across the outer membrane leaflet of the blood-brain barrier via APOE4 receptors, whereas DHA-lysoPC is transported across the inner membrane leaflet of the blood-brain barrier via a specific protein called Mfsd2a. Dietary supplementation of this lysoPC specific form of DHA is a novel therapy and is used to decrease the risk of various neurodegenerative disorders. Currently, structured glycerides of DHA - novel nutraceutical agents - are being widely used for the prevention and treatment of various neurological diseases. However, it is important to fully understand their metabolic regulation and mechanism of transportation to the brain. This article comprehensively reviews various studies that have evaluated the bioavailability of DHA, mechanisms of DHA transport, and role of DHA in preventing neurodegenerative disorders, which provides better insight into the pathophysiology of these disorders and use of structured DHA in improving neurological health.
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Affiliation(s)
- Jeyakumar Balakrishnan
- Central Research Laboratory, Vinayaka Mission's Medical College and Hospital, Vinayaka Mission's Research Foundation (Deemed to be University), Karaikal, Puducherry, India.
| | - Suganya Kannan
- Central Research Laboratory, Vinayaka Mission's Medical College and Hospital, Vinayaka Mission's Research Foundation (Deemed to be University), Karaikal, Puducherry, India
| | - Ambujam Govindasamy
- Department of General Surgery, Vinayaka Mission's Medical College and Hospital, Vinayaka Mission Research Foundation (Deemed to be University), Karaikal. Puducherry, India
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Alicea GM, Rebecca VW, Goldman AR, Fane ME, Douglass SM, Behera R, Webster MR, Kugel CH, Ecker BL, Caino MC, Kossenkov AV, Tang HY, Frederick DT, Flaherty KT, Xu X, Liu Q, Gabrilovich DI, Herlyn M, Blair IA, Schug ZT, Speicher DW, Weeraratna AT. Changes in Aged Fibroblast Lipid Metabolism Induce Age-Dependent Melanoma Cell Resistance to Targeted Therapy via the Fatty Acid Transporter FATP2. Cancer Discov 2020; 10:1282-1295. [PMID: 32499221 DOI: 10.1158/2159-8290.cd-20-0329] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 11/16/2022]
Abstract
Older patients with melanoma (>50 years old) have poorer prognoses and response rates to targeted therapy compared with young patients (<50 years old), which can be driven, in part, by the aged microenvironment. Here, we show that aged dermal fibroblasts increase the secretion of neutral lipids, especially ceramides. When melanoma cells are exposed to the aged fibroblast lipid secretome, or cocultured with aged fibroblasts, they increase the uptake of lipids via the fatty acid transporter FATP2, which is upregulated in melanoma cells in the aged microenvironment and known to play roles in lipid synthesis and accumulation. We show that blocking FATP2 in melanoma cells in an aged microenvironment inhibits their accumulation of lipids and disrupts their mitochondrial metabolism. Inhibiting FATP2 overcomes age-related resistance to BRAF/MEK inhibition in animal models, ablates tumor relapse, and significantly extends survival time in older animals. SIGNIFICANCE: These data show that melanoma cells take up lipids from aged fibroblasts, via FATP2, and use them to resist targeted therapy. The response to targeted therapy is altered in aged individuals because of the influences of the aged microenvironment, and these data suggest FATP2 as a target to overcome resistance.See related commentary by Montal and White, p. 1255.This article is highlighted in the In This Issue feature, p. 1241.
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Affiliation(s)
- Gretchen M Alicea
- The Wistar Institute, Philadelphia, Pennsylvania.,University of the Sciences, Philadelphia, Pennsylvania.,Johns Hopkins School of Public Health, Baltimore, Maryland.,Johns Hopkins School of Medicine, Baltimore, Maryland
| | | | | | - Mitchell E Fane
- The Wistar Institute, Philadelphia, Pennsylvania.,Johns Hopkins School of Public Health, Baltimore, Maryland.,Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Stephen M Douglass
- The Wistar Institute, Philadelphia, Pennsylvania.,Johns Hopkins School of Public Health, Baltimore, Maryland.,Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Reeti Behera
- The Wistar Institute, Philadelphia, Pennsylvania
| | - Marie R Webster
- The Wistar Institute, Philadelphia, Pennsylvania.,Lankenau Institute for Medical Research, Wynnewood, Pennsylvania
| | | | - Brett L Ecker
- The Wistar Institute, Philadelphia, Pennsylvania.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | | | | | | | - Xiaowei Xu
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Qin Liu
- The Wistar Institute, Philadelphia, Pennsylvania
| | | | | | - Ian A Blair
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | - Ashani T Weeraratna
- The Wistar Institute, Philadelphia, Pennsylvania. .,Johns Hopkins School of Public Health, Baltimore, Maryland.,Johns Hopkins School of Medicine, Baltimore, Maryland
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12
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Wang X, Sun S, Cao X, Gao J. Quantitative Phosphoproteomic Analysis Reveals the Regulatory Networks of Elovl6 on Lipid and Glucose Metabolism in Zebrafish. Int J Mol Sci 2020; 21:ijms21082860. [PMID: 32325903 PMCID: PMC7215441 DOI: 10.3390/ijms21082860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/09/2020] [Accepted: 04/14/2020] [Indexed: 11/18/2022] Open
Abstract
Elongation of very long-chain fatty acids protein 6 (Elovl6) has been reported to be associated with clinical treatments of a variety of metabolic diseases. However, there is no systematic and comprehensive study to reveal the regulatory role of Elovl6 in mRNA, protein and phosphorylation levels. We established the first knock-out (KO), elovl6−/−, in zebrafish. Compared with wild type (WT) zebrafish, KO presented significant higher whole-body lipid content and lower content of fasting blood glucose. We utilized RNA-Seq, tandem mass tag (TMT) labeling-based quantitative technology and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to perform the transcriptomic, proteomic and phosphoproteomic analyses of livers from WT and elovl6−/− zebrafish. There were 734 differentially expressed genes (DEG) and 559 differentially expressed proteins (DEP) between elovl6−/− and WT zebrafish, identified out of quantifiable 47251 transcripts and 5525 proteins. Meanwhile, 680 differentially expressed phosphoproteins (DEPP) with 1054 sites were found out of quantifiable 1230 proteins with 3604 sites. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis of the transcriptomic and proteomic data further suggested that the abnormal lipid metabolism and glucose metabolism in KO were mainly related to fatty acid degradation and biosynthesis, glycolysis/gluconeogenesis and PPAR signaling pathway. Based on phosphoproteomic analyses, some kinases critical for lipid metabolism and glucose metabolism, including ribosomal protein S6 kinase (Rps6kb), mitogen-activated protein kinase14 (Mapk14) and V-akt murine thymoma viral oncogene homolog 2-like (Akt2l), were identified. These results allowed us to catch on the regulatory networks of elovl6 on lipid and glucose metabolism in zebrafish. To our knowledge, this is the first multi-omic study of zebrafish lacking elovl6, which provides strong datasets to better understand many lipid/glucose metabolic risks posed to human health.
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Affiliation(s)
- Xueting Wang
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education/National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan 430070, China; (X.W.); (S.S.); (X.C.)
| | - Shouxiang Sun
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education/National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan 430070, China; (X.W.); (S.S.); (X.C.)
| | - Xiaojuan Cao
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education/National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan 430070, China; (X.W.); (S.S.); (X.C.)
- College of Fisheries, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Jian Gao
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education/National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan 430070, China; (X.W.); (S.S.); (X.C.)
- College of Fisheries, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China
- Correspondence: ; Tel.: +86-(027)-8728-2113
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13
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Jung HS, Shimizu-Albergine M, Shen X, Kramer F, Shao D, Vivekanandan-Giri A, Pennathur S, Tian R, Kanter JE, Bornfeldt KE. TNF-α induces acyl-CoA synthetase 3 to promote lipid droplet formation in human endothelial cells. J Lipid Res 2020; 61:33-44. [PMID: 31722970 PMCID: PMC6939593 DOI: 10.1194/jlr.ra119000256] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/22/2019] [Indexed: 01/20/2023] Open
Abstract
Chronic inflammation contributes to cardiovascular disease. Increased levels of the inflammatory cytokine, TNF-α, are often present in conditions associated with cardiovascular disease risk, and TNF-α induces a number of pro-atherogenic effects in macrovascular endothelial cells, including expression of adhesion molecules and chemokines, and lipoprotein uptake and transcytosis to the subendothelial tissue. However, little is known about the roles of acyl-CoA synthetases (ACSLs), enzymes that esterify free fatty acids into their acyl-CoA derivatives, or about the effects of TNF-α on ACSLs in endothelial cells. Therefore, we investigated the effects of TNF-α on ACSLs and downstream lipids in cultured human coronary artery endothelial cells and human umbilical vein endothelial cells. We demonstrated that TNF-α induces ACSL1, ACSL3, and ACSL5, but not ACSL4, in both cell types. TNF-α also increased oleoyl-CoA levels, consistent with the increased ACSL3 expression. RNA-sequencing demonstrated that knockdown of ACSL3 had no marked effects on the TNF-α transcriptome. Instead, ACSL3 was required for TNF-α-induced lipid droplet formation in cells exposed to oleic acid. These results demonstrate that increased acyl-CoA synthesis as a result of ACSL3 induction is part of the TNF-α response in human macrovascular endothelial cells.
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Affiliation(s)
- Hye Seung Jung
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109
| | - Masami Shimizu-Albergine
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109
| | - Xia Shen
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109
| | - Farah Kramer
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109
| | - Dan Shao
- Departments of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109
| | | | | | - Rong Tian
- Departments of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109
| | - Jenny E Kanter
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109
| | - Karin E Bornfeldt
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109; Pathology, University of Washington, Seattle, WA 98109.
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14
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Lv Y, Cao Y, Gao Y, Yun J, Yu Y, Zhang L, Hu Z, Liu L, Xue J, Zhang G. Effect of ACSL3 Expression Levels on Preadipocyte Differentiation in Chinese Red Steppe Cattle. DNA Cell Biol 2019; 38:945-954. [DOI: 10.1089/dna.2018.4443] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Yang Lv
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Yang Cao
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
- Key Laboratory of Beef Cattle Genetics and Breeding in Ministry of Agriculture and Rural Agriculture, Changchun, China
| | - Yi Gao
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
| | - Jinyan Yun
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
| | - Yongsheng Yu
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
| | - Lichun Zhang
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
| | - Zhongchang Hu
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
| | - Lixiang Liu
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Jiajia Xue
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Guoliang Zhang
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Gongzhuling, China
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
- Key Laboratory of Beef Cattle Genetics and Breeding in Ministry of Agriculture and Rural Agriculture, Changchun, China
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15
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Yan Q, Tang S, Zhou C, Han X, Tan Z. Effects of Free Fatty Acids with Different Chain Lengths and Degrees of Saturability on the Milk Fat Synthesis in Primary Cultured Bovine Mammary Epithelial Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:8485-8492. [PMID: 31304752 DOI: 10.1021/acs.jafc.9b02905] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
How short-chain fatty acids (FAs) affect cell membrane morphology and milk fat biosynthesis in mammary epithelial cells (MECs) is yet unclear. This study investigated the primary bovine MEC response to different FAs. We observed that the cell surface ultrastructures were influenced by chain length and degree of saturability of FAs. The CD36, FATP1, and FABP3 gene expression was affected independent of the type of FA. FASN, LPIN1, PPARα, and PPARγ transcripts were more sensitive to the short-chain FAs (acetic and β-hydroxybutyric acids). Furthermore, short-chain FAs inclined to regulate FA degradation-, elongation-, and metabolism-associated pathways, while long-chain FAs (stearic and trans-10,cis-12 conjugated linolenic acids) modulated extracellular matrix-receptor interaction-, transcriptional misregulation-, microRNA-, and ribosome biogenesis-related pathways. However, triacylglycerol accumulation in the cytoplasm was not changed by all of the FAs. Overall, FAs with different chain lengths and degrees of saturability could differentially alter primary bovine MEC cell morphology and influence protein profiles involved in milk fat synthesis pathways.
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Affiliation(s)
- Qiongxian Yan
- Chinese Academy of Sciences (CAS) Key Laboratory of Agro-ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture , Chinese Academy of Sciences , Changsha , Hunan 410125 , People's Republic of China
- Hunan Co-Innovation Center for Utilization of Botanical Functional Ingredients , Changsha , Hunan 410128 , People's Republic of China
| | - Shaoxun Tang
- Chinese Academy of Sciences (CAS) Key Laboratory of Agro-ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture , Chinese Academy of Sciences , Changsha , Hunan 410125 , People's Republic of China
- Hunan Co-Innovation Center of Animal Production Safety (CICAPS) , Changsha , Hunan 410128 , People's Republic of China
| | - Chuanshe Zhou
- Chinese Academy of Sciences (CAS) Key Laboratory of Agro-ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture , Chinese Academy of Sciences , Changsha , Hunan 410125 , People's Republic of China
- Hunan Co-Innovation Center of Animal Production Safety (CICAPS) , Changsha , Hunan 410128 , People's Republic of China
| | - Xuefeng Han
- Chinese Academy of Sciences (CAS) Key Laboratory of Agro-ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture , Chinese Academy of Sciences , Changsha , Hunan 410125 , People's Republic of China
- Hunan Co-Innovation Center for Utilization of Botanical Functional Ingredients , Changsha , Hunan 410128 , People's Republic of China
| | - Zhiliang Tan
- Chinese Academy of Sciences (CAS) Key Laboratory of Agro-ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture , Chinese Academy of Sciences , Changsha , Hunan 410125 , People's Republic of China
- Hunan Co-Innovation Center of Animal Production Safety (CICAPS) , Changsha , Hunan 410128 , People's Republic of China
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16
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Khan S, Cabral PD, Schilling WP, Schmidt ZW, Uddin AN, Gingras A, Madhavan SM, Garvin JL, Schelling JR. Kidney Proximal Tubule Lipoapoptosis Is Regulated by Fatty Acid Transporter-2 (FATP2). J Am Soc Nephrol 2017; 29:81-91. [PMID: 28993506 DOI: 10.1681/asn.2017030314] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/08/2017] [Indexed: 11/03/2022] Open
Abstract
Albuminuria and tubular atrophy are among the highest risks for CKD progression to ESRD. A parsimonious mechanism involves leakage of albumin-bound nonesterified fatty acids (NEFAs) across the damaged glomerular filtration barrier and subsequent reabsorption by the downstream proximal tubule, causing lipoapoptosis. We sought to identify the apical proximal tubule transporter that mediates NEFA uptake and cytotoxicity. We observed transporter-mediated uptake of fluorescently labeled NEFA in cultured proximal tubule cells and microperfused rat proximal tubules, with greater uptake from the apical surface than from the basolateral surface. Protein and mRNA expression analyses revealed that kidney proximal tubules express transmembrane fatty acid transporter-2 (FATP2), encoded by Slc27a2, but not the other candidate transporters CD36 and free fatty acid receptor 1. Kidney FATP2 localized exclusively to proximal tubule epithelial cells along the apical but not the basolateral membrane. Treatment of mice with lipidated albumin to induce proteinuria caused a decrease in the proportion of tubular epithelial cells and an increase in the proportion of interstitial space in kidneys from wild-type but not Slc27a2-/- mice. Ex vivo microperfusion and in vitro experiments with NEFA-bound albumin at concentrations that mimic apical proximal tubule exposure during glomerular injury revealed significantly reduced NEFA uptake and palmitate-induced apoptosis in microperfused Slc27a2-/- proximal tubules and Slc27a2-/- or FATP2 shRNA-treated proximal tubule cell lines compared with wild-type or scrambled oligonucleotide-treated cells, respectively. We conclude that FATP2 is a major apical proximal tubule NEFA transporter that regulates lipoapoptosis and may be an amenable target for the prevention of CKD progression.
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Affiliation(s)
- Shenaz Khan
- Department of Medicine, The MetroHealth System and
| | - Pablo D Cabral
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
| | - William P Schilling
- Department of Medicine, The MetroHealth System and.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
| | | | - Asif N Uddin
- Department of Medicine, The MetroHealth System and
| | | | | | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
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17
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Jabłońska-Trypuć A, Pankiewicz W, Czerpak R. Traumatic Acid Reduces Oxidative Stress and Enhances Collagen Biosynthesis in Cultured Human Skin Fibroblasts. Lipids 2016; 51:1021-35. [PMID: 27423205 PMCID: PMC5009161 DOI: 10.1007/s11745-016-4174-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/04/2016] [Indexed: 12/16/2022]
Abstract
Traumatic acid (TA) is a plant hormone (cytokinin) that in terms of chemical structure belongs to the group of fatty acids derivatives. It was isolated from Phaseolus vulgaris. TA activity and its influence on human cells and organism has not previously been the subject of research. The aim of this study was to examine the effects of TA on collagen content and basic oxidative stress parameters, such as antioxidative enzyme activity, reduced glutathione, thiol group content, and lipid peroxidation in physiological conditions. The results show a stimulatory effect of TA on tested parameters. TA caused a decrease in membrane phospholipid peroxidation and exhibited protective properties against ROS production. It also increases protein and collagen biosynthesis and its secretion into the culture medium. The present findings reveal that TA exhibits multiple and complex activity in fibroblast cells in vitro. TA, with its activity similar to unsaturated fatty acids, shows antioxidant and stimulatory effects on collagen biosynthesis. It is a potentially powerful agent with applications in the treatment of many skin diseases connected with oxidative stress and collagen biosynthesis disorders.
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Affiliation(s)
- Agata Jabłońska-Trypuć
- Faculty of Civil and Environmental Engineering, Division of Sanitary Biology and Biotechnology, Bialystok University of Technology, Wiejska Street 45E, 15-351, Białystok, Poland.
| | - Walentyn Pankiewicz
- University of Medical Science in Białystok, Krakowska Street 9, 15-875, Białystok, Poland
| | - Romuald Czerpak
- University of Medical Science in Białystok, Krakowska Street 9, 15-875, Białystok, Poland
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18
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Pinolenic Acid Downregulates Lipid Anabolic Pathway in HepG2 Cells. Lipids 2016; 51:847-55. [DOI: 10.1007/s11745-016-4149-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 03/31/2016] [Indexed: 12/15/2022]
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19
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Early Loss of Blood-Brain Barrier Integrity Precedes NOX2 Elevation in the Prefrontal Cortex of an Animal Model of Psychosis. Mol Neurobiol 2016; 54:2031-2044. [PMID: 26910819 PMCID: PMC5355521 DOI: 10.1007/s12035-016-9791-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/11/2016] [Indexed: 12/29/2022]
Abstract
The social isolation rearing of young adult rats is a model of psychosocial stress and provides a nonpharmacological tool to study alterations reminiscent of symptoms seen in psychosis. We have previously demonstrated that social isolation in rats leads to increased oxidative stress and to cerebral NOX2 elevations. Here, we investigated early alterations in mRNA expression leading to increased NOX2 in the brain. Rats were exposed to a short period of social isolation (1 week) and real-time polymerase chain reaction (PCR) for mRNA expression of genes involved in blood-brain barrier (BBB) formation and integrity (ORLs, Vof 21 and Vof 16, Leng8, Vnr1, and Trank 1 genes) was performed. Real-time PCR experiments, immunohistochemistry, and Western blotting analysis showed an increased expression of these genes and related proteins in isolated rats with respect to control animals. The expression of specific markers of BBB integrity, such as matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), occludin 1, and plasmalemmal vesicle associated protein-1 (PV-1), was also significantly altered after 1 week of social isolation. BBB permeability, evaluated by quantification of Evans blue dye extravasation, as well as interstitial fluid, was significantly increased in rats isolated for 1 week with respect to controls. Isolation-induced BBB disruption was also accompanied by a significant increase of Interleukin 6 (IL-6) expression. Conversely, no differences in NOX2 levels were detected at this time point. Our study demonstrates that BBB disruption precedes NOX2 elevations in the brain. These results provide new insights in the interplay of mechanisms linking psychosocial stress to early oxidative stress in the brain, disruption of the BBB, and the development of mental disorders.
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20
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Black PN, Ahowesso C, Montefusco D, Saini N, DiRusso CC. Fatty Acid Transport Proteins: Targeting FATP2 as a Gatekeeper Involved in the Transport of Exogenous Fatty Acids. MEDCHEMCOMM 2016; 7:612-622. [PMID: 27446528 DOI: 10.1039/c6md00043f] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The fatty acid transport proteins (FATP) are classified as members of the Solute Carrier 27 (Slc27) family of proteins based on their ability to function in the transport of exogenous fatty acids. These proteins, when localized to the plasma membrane or at intracellular membrane junctions with the endoplasmic reticulum, function as a gate in the regulated transport of fatty acids and thus represent a therapeutic target to delimit the acquisition of fatty acids that contribute to disease as in the case of fatty acid overload. To date, FATP1, FATP2, and FATP4 have been used as targets in the selection of small molecule inhibitors with the goal of treating insulin resistance and attenuating dietary absorption of fatty acids. Several studies targeting FATP1 and FATP4 were based on the intrinsic acyl CoA synthetase activity of these proteins and not on transport directly. While several classes of compounds were identified as potential inhibitors of fatty acid transport, in vivo studies using a mouse model failed to provide evidence these compounds were effective in blocking or attenuating fatty acid transport. Studies targeting FATP2 employed a naturally occurring splice variant, FATP2b, which lacks intrinsic acyl CoA synthetase due to the deletion of exon 3, yet is fully functional in fatty acid transport. These studies identified two compounds, 5'-bromo-5-phenyl-spiro[3H-1,3,4-thiadiazole-2,3'-indoline]-2'-one), now referred to as Lipofermata, and 2-benzyl-3-(4-chlorophenyl)-5-(4-nitrophenyl)pyrazolo[1,5-a]pyrimidin-7(4H)-one, now called Grassofermata, that are effective fatty acid transport inhibitors both in vitro using a series of model cell lines and in vivo using a mouse model.
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Affiliation(s)
- Paul N Black
- Department of Biochemistry, University of Nebraska, Lincoln, NE
| | | | | | - Nipun Saini
- Department of Biochemistry, University of Nebraska, Lincoln, NE
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21
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Yan G, Li B, Xin X, Xu M, Ji G, Yu H. MicroRNA-34a Promotes Hepatic Stellate Cell Activation via Targeting ACSL1. Med Sci Monit 2015; 21:3008-15. [PMID: 26437572 PMCID: PMC4601392 DOI: 10.12659/msm.894000] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 04/13/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The incidence of liver fibrosis remains high due to the lack of effective therapies. Our previous work found that microRNA (miR)-34a expression was increased, while acy1-CoA synthetase long-chain family member1 (ACSL1) was decreased, in a dimethylnitrosamine (DNS)-induced hepatic fibrosis rat model. We hypothesized that miR-34a may play a role in the process of hepatic fibrosis by targeting ACSL1. MATERIAL AND METHODS From days 2 to 14, cultured primary hepatic stellate cells (HSCs) underwent cell morphology, immunocytochemical staining, and quantitative reverse transcription PCR (RT-qPCR) for alpha smooth muscle actin (a-SMA), desmin, rno-miR-34a, and ACSL1 expression. Wild-type and mutant luciferase reporter plasmids were constructed according to the predicted miR-34a binding site on the 3'-untranslated region (UTR) of the ACSL1 mRNA and then transfected into HEK293 cells. rno-miR-34a was silenced in HSCs to confirm that rno-miR-34a negatively regulates ACSL1 expression. mRNA and protein expression of α-SMA, type I collagen, and desmin were assayed in miR-34a-silenced HSCs. RESULTS HSCs were deemed quiescent during the first 3 days and activated after 10 days. rno-miR-34a expression increased, and ACSL1 expression decreased, from day 2 to 7 to 14. rno-miR-34a was shown to specifically bind to the 3'-UTR of ACSL1. miR-34a-silenced HSCs showed higher ACSL1and lower α-SMA, type I collagen, and desmin expression than that of matching negative controls and non-transfected cells. CONCLUSIONS miR-34a appears to play an important role in the process of liver fibrosis by targeting ACSL1 and may show promise as a therapeutic molecular target for hepatic fibrosis.
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Affiliation(s)
- Gangli Yan
- Department of Pathology, Changzheng Hospital, The Second Military Medical University, Shanghai, P.R. China
- Department of Neurology, The No. 161 People’s Liberation Army (PLA) Hospital, Wuhan, Hubei, P.R. China
| | - Binbin Li
- Department of Pathology, Changzheng Hospital, The Second Military Medical University, Shanghai, P.R. China
| | - Xuan Xin
- Department of Pathology, Changzheng Hospital, The Second Military Medical University, Shanghai, P.R. China
- Department of Pathology, The General Hospital of the Jinan Military Command, Jinan, Shandong, P.R. China
| | - Midie Xu
- Department of Pathology, Changzheng Hospital, The Second Military Medical University, Shanghai, P.R. China
| | - Guoqing Ji
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P.R. China
| | - Hongyu Yu
- Department of Pathology, Changzheng Hospital, The Second Military Medical University, Shanghai, P.R. China
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22
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Ahowesso C, Black PN, Saini N, Montefusco D, Chekal J, Malosh C, Lindsley CW, Stauffer SR, DiRusso CC. Chemical inhibition of fatty acid absorption and cellular uptake limits lipotoxic cell death. Biochem Pharmacol 2015; 98:167-81. [PMID: 26394026 DOI: 10.1016/j.bcp.2015.09.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/03/2015] [Indexed: 12/31/2022]
Abstract
Chronic elevation of plasma free fatty acid (FFA) levels is commonly associated with obesity, type 2 diabetes, cardiovascular disease and some cancers. Experimental evidence indicates FFA and their metabolites contribute to disease development through lipotoxicity. Previously, we identified a specific fatty acid transport inhibitor CB16.2, a.k.a. Lipofermata, using high throughput screening methods. In this study, efficacy of transport inhibition was measured in four cell lines that are models for myocytes (mmC2C12), pancreatic β-cells (rnINS-1E), intestinal epithelial cells (hsCaco-2), and hepatocytes (hsHepG2), as well as primary human adipocytes. The compound was effective in inhibiting uptake with IC50s between 3 and 6μM for all cell lines except human adipocytes (39μM). Inhibition was specific for long and very long chain fatty acids but had no effect on medium chain fatty acids (C6-C10), which are transported by passive diffusion. Derivatives of Lipofermata were evaluated to understand structural contributions to activity. Lipofermata prevented palmitate-mediated oxidative stress, induction of BiP and CHOP, and cell death in a dose-dependent manner in hsHepG2 and rnINS-1E cells, suggesting it will prevent induction of fatty acid-mediated cell death pathways and lipotoxic disease by channeling excess fatty acids to adipose tissue and away from liver and pancreas. Importantly, mice dosed orally with Lipofermata were not able to absorb (13)C-oleate demonstrating utility as an inhibitor of fatty acid absorption from the gut.
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Affiliation(s)
- Constance Ahowesso
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Paul N Black
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Nipun Saini
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - David Montefusco
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Jessica Chekal
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Chrysa Malosh
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, United States; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States
| | - Shaun R Stauffer
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, United States; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States
| | - Concetta C DiRusso
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States.
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23
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Zhang X, Tian Y, Zhang H, Kavishwar A, Lynes M, Brownell AL, Sun H, Tseng YH, Moore A, Ran C. Curcumin analogues as selective fluorescence imaging probes for brown adipose tissue and monitoring browning. Sci Rep 2015; 5:13116. [PMID: 26269357 PMCID: PMC4534785 DOI: 10.1038/srep13116] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 07/16/2015] [Indexed: 01/10/2023] Open
Abstract
Manipulation of brown adipose tissue (BAT) and browning of white adipose tissue (WAT) can be promising new approaches to counter metabolic disorder diseases in humans. Imaging probes that could consistently monitor BAT mass and browning of WAT are highly desirable. In the course of our imaging probe screening, we found that BAT could be imaged with curcumin analogues in mice. However, the poor BAT selectivity over WAT and short emissions of the lead probes promoted further lead optimization. Limited uptake mechanism studies suggested that CD36/FAT (fatty acid transporter) probably contributed to the facilitated uptake of the probes. By increasing the stereo-hindrance of the lead compound, we designed CRANAD-29 to extend the emission and increase the facilitated uptake, thus increasing its BAT selectivity. Our data demonstrated that CRANAD-29 had significantly improved selectivity for BAT over WAT, and could be used for imaging BAT mass change in a streptozotocin-induced diabetic mouse model, as well as for monitoring BAT activation under cold exposure. In addition, CRANAD-29 could be used for monitoring the browning of subcutaneous WAT (sWAT) induced by β3-adrenoceptor agonist CL-316, 243.
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Affiliation(s)
- Xueli Zhang
- 1] Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA [2] School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China [3] Department of pharmacy, ZhongDa Hospital, Southeast University, Nanjing 210009, China
| | - Yanli Tian
- 1] Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA [2] Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Hongbin Zhang
- Joslin Diabetes Center, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215
| | - Amol Kavishwar
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Matthew Lynes
- Joslin Diabetes Center, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215
| | - Anna-Liisa Brownell
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Hongbin Sun
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yu-Hua Tseng
- Joslin Diabetes Center, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA 02215
| | - Anna Moore
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
| | - Chongzhao Ran
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA
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24
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Zhang F, Guo S, Zhang M, Zhang Z, Guo Y. Characterizing ion mobility and collision cross section of fatty acids using electrospray ion mobility mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:906-913. [PMID: 26349645 DOI: 10.1002/jms.3600] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/29/2015] [Accepted: 03/31/2015] [Indexed: 06/05/2023]
Abstract
This study investigated the ion mobility (IM) and the collision cross section (CCS) of fatty acids (FAs) using electrospray IM MS. The IM analysis of 18 FA ions showed intriguing differences among the saturated FAs, monounsaturated FAs, multi-unsaturated FAs, and cis-isomer/trans-isomer with respect to the aliphatic tail chains. The length of aliphatic tail chain present in the ion structures had a strong influence on the differentiation of drift, while the number of double bond showed a weaker influence. The tiny drift differences between cis-isomer and trans-isomer were also observed. In the CCS measurements, two internal standards were involved in the mobility calibration and accuracy estimation. It insured our empirical CCS values were of high experimental precision (±0.35% or better) and accuracy (±0.25% or better). Moreover, the mass-to-charge ratio (m/z) - mobility plots obtained by ion mobility spectrometry with mass spectrometry analysis of FAs - was used to investigate the structural relationship between the molecules. Each series of FAs sharing a similar structure was aligned in the linear plot. Finally, the developed procedure was applied to the determination of FAs in rat adipose tissues, and it allowed the presence of 13 FAs to be confirmed with their exact masses and CCS values. These studies reveal the direct relationship between the behaviors in IM and the molecular structures and thus may provide further validations to the FA identification process.
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Affiliation(s)
- Fang Zhang
- National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Su Guo
- Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Manyu Zhang
- Agilent Technologies Co. Ltd. (China), No. 1350 North Sichuan Road, Shanghai, 200080, China
| | - Zhixu Zhang
- Agilent Technologies Co. Ltd. (China), No. 1350 North Sichuan Road, Shanghai, 200080, China
| | - Yinlong Guo
- National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
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25
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Lanier JS, Corl BA. Challenges in enriching milk fat with polyunsaturated fatty acids. J Anim Sci Biotechnol 2015; 6:26. [PMID: 26110055 PMCID: PMC4479322 DOI: 10.1186/s40104-015-0025-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 06/02/2015] [Indexed: 01/14/2023] Open
Abstract
Milk fatty acid composition is determined by several factors including diet. The milk fatty acid profile of dairy cows is low in polyunsaturated fatty acids, especially those of the n-3 series. Efforts to change and influence fatty acid profile with longer chain polyunsaturated fatty acids have proven challenging. Several barriers prevent easy transfer of dietary polyunsaturated fatty acids to milk fat including rumen biohydrogenation and fatty acid esterification. The potential for cellular uptake and differences in fatty acid incorporation into milk fat might also have an effect, though this has received less research effort. Given physiological impediments to enriching milk fat with polyunsaturated fatty acids, manipulating the genome of the cow might provide a greater increase than diet alone, but this too may be challenged by the physiology of the cow.
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Affiliation(s)
| | - Benjamin A Corl
- Department of Dairy Science, Virginia Tech, Blacksburg, VA 24061-0315 USA
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26
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Kan CFK, Singh AB, Dong B, Shende VR, Liu J. PPARδ activation induces hepatic long-chain acyl-CoA synthetase 4 expression in vivo and in vitro. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:577-87. [PMID: 25645621 DOI: 10.1016/j.bbalip.2015.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/07/2015] [Accepted: 01/14/2015] [Indexed: 12/29/2022]
Abstract
The arachidonic acid preferred long-chain acyl-CoA synthetase 4 (ACSL4) is a key enzyme for fatty acid metabolism in various metabolic tissues. In this study, we utilized hamsters fed a normal chow diet, a high-fat diet or a high cholesterol and high fat diet (HCHFD) as animal models to explore novel transcriptional regulatory mechanisms for ACSL4 expression under hyperlipidemic conditions. Through cloning hamster ACSL4 homolog and tissue profiling ACSL4 mRNA and protein expressions we observed a selective upregulation of ACSL4 in testis and liver of HCHFD fed animals. Examination of transcriptional activators of the ACSL family revealed an increased hepatic expression of PPARδ but not PPARα in HCHFD fed hamsters. To explore a role of PPARδ in dietary cholesterol-mediated upregulation of ACSL4, we administered a PPARδ specific agonist L165041 to normolipidemic and dyslipidemic hamsters. We observed significant increases of hepatic ACSL4 mRNA and protein levels in all L165041-treated hamsters as compared to control animals. The induction of ACSL4 expression by L165041 in liver tissue in vivo was recapitulated in human primary hepatocytes and hepatocytes isolated from hamster and mouse. Moreover, employing the approach of adenovirus-mediated gene knockdown, we showed that depletion of PPARδ in hamster hepatocytes specifically reduced ACSL4 expression. Finally, utilizing HepG2 as a model system, we demonstrate that PPARδ activation leads to increased ACSL4 promoter activity, mRNA and protein expression, and consequently higher arachidonoyl-CoA synthetase activity. Taken together, we have discovered a novel PPARδ-mediated regulatory mechanism for ACSL4 expression in liver tissue and cultured hepatic cells.
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Affiliation(s)
- Chin Fung Kelvin Kan
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States
| | - Amar Bahadur Singh
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States
| | - Bin Dong
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States
| | - Vikram Ravindra Shende
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States; Department of Medicine, Stanford University, Stanford, CA 94305, United States
| | - Jingwen Liu
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States.
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27
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Szalowska E, Tesfay HA, van Hijum SAFT, Kersten S. Transcriptomic signatures of peroxisome proliferator-activated receptor α (PPARα) in different mouse liver models identify novel aspects of its biology. BMC Genomics 2014; 15:1106. [PMID: 25511156 PMCID: PMC4378209 DOI: 10.1186/1471-2164-15-1106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 12/01/2014] [Indexed: 12/15/2022] Open
Abstract
Background The peroxisome proliferator-activated receptor alpha (PPARα) is a ligand-activated transcription factor that regulates lipid catabolism and inflammation and is hepatocarcinogenic in rodents. It is presumed that the functions of PPARα in liver depend on cross-talk between parenchymal (hepatocytes) and non-parenchymal (Kupffer and endothelial cells) fractions as well as inter-organ interactions. In order to determine how cellular composition and inter-organ interactions influence gene expression upon pharmacological activation of PPARα, we performed a meta-analysis of transcriptomics data obtained from mouse hepatocytes (containing only the parenchymal fraction), mouse liver slices (containing both fractions), and mouse livers exposed to a PPARα agonist. The aim was to obtain a comprehensive view of common and model-specific PPARα-dependent genes and biological processes to understand the impact of cross-talk between parenchymal and non-parenchymal fractions as well as the effect of inter-organ interactions on the hepatic PPARα transcriptome. To this end we analyzed microarray data of experiments performed in mouse primary hepatocytes treated with the PPARα agonist Wy14643 for 6 or 24 h (in vitro), mouse precision cut liver slices treated with Wy14643 for 24 h (ex vivo), and livers of wild type and Ppara knockout mice treated with Wy14643 for 6 h or 5 days (in vivo). Results In all models, activation of PPARα significantly altered processes related to various aspects of lipid metabolism. In ex vivo and in vivo models, PPARα activation significantly regulated processes involved in inflammation; these processes were unaffected in hepatocytes. Only in vivo models showed significant regulation of genes involved in coagulation, carcinogenesis, as well as vesicular trafficking and extracellular matrix. Conclusions PPARα-dependent regulation of genes/processes involved in lipid metabolism is mostly independent of the presence of non-parenchymal cells or systemic factors, as it was observed in all liver models. PPARα-dependent regulation of inflammatory genes requires the presence of non-parenchymal cells, as it was observed only ex vivo and in vivo. However, the full spectrum of PPARα biology at the level of lipid metabolism, immunity, carcinogenesis, as well as novel aspects of PPARα signaling such as coagulation, vesicular trafficking and the extracellular matrix, seems to require systemic factors, as it was observed exclusively in vivo. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1106) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ewa Szalowska
- RIKILT - Institute of Food Safety, Wageningen UR, P,O, Box 230, 6700 AE Wageningen, The Netherlands.
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28
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Rohm B, Riedel A, Ley JP, Widder S, Krammer GE, Somoza V. Capsaicin, nonivamide and trans-pellitorine decrease free fatty acid uptake without TRPV1 activation and increase acetyl-coenzyme A synthetase activity in Caco-2 cells. Food Funct 2014; 6:173-85. [PMID: 25422952 DOI: 10.1039/c4fo00435c] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Red pepper and its major pungent component, capsaicin, have been associated with hypolipidemic effects in rats, although mechanistic studies on the effects of capsaicin and/or structurally related compounds on lipid metabolism are scarce. In this work, the effects of capsaicin and its structural analog nonivamide, the aliphatic alkamide trans-pellitorine and vanillin as the basic structural element of all vanilloids on the mechanisms of intestinal fatty acid uptake in differentiated intestinal Caco-2 cells were studied. Capsaicin and nonivamide were found to reduce fatty acid uptake, with IC₅₀ values of 0.49 μM and 1.08 μM, respectively. trans-Pellitorine was shown to reduce fatty acid uptake by 14.0±2.14% at 100 μM, whereas vanillin was not effective, indicating a pivotal role of the alkyl chain with the acid amide group in fatty acid uptake by Caco-2 cells. This effect was associated neither with the activation of the transient receptor potential cation channel subfamily V member 1 (TRPV1) or the epithelial sodium channel (ENaC) nor with effects on paracellular transport or glucose uptake. However, acetyl-coenzyme A synthetase activity increased (p<0.05) in the presence of 10 μM capsaicin, nonivamide or trans-pellitorine, pointing to an increased fatty acid biosynthesis that might counteract the decreased fatty acid uptake.
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Affiliation(s)
- Barbara Rohm
- Christian Doppler Laboratory for Bioactive Aroma Compounds, Faculty of Chemistry, University of Vienna, Althanstraße 14, 1090 Vienna, Austria.
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29
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Cruz-Garcia L, Schlegel A. Lxr-driven enterocyte lipid droplet formation delays transport of ingested lipids. J Lipid Res 2014; 55:1944-58. [PMID: 25030662 DOI: 10.1194/jlr.m052845] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Liver X receptors (Lxrs) are master regulators of cholesterol catabolism, driving the elimination of cholesterol from the periphery to the lumen of the intestine. Development of pharmacological agents to activate Lxrs has been hindered by synthetic Lxr agonists' induction of hepatic lipogenesis and hypertriglyceridemia. Elucidating the function of Lxrs in regulating enterocyte lipid handling might identify novel aspects of lipid metabolism that are pharmacologically amenable. We took a genetic approach centered on the single Lxr gene nr1h3 in zebrafish to study the role of Lxr in enterocyte lipid metabolism. Loss of nr1h3 function causes anticipated gene regulatory changes and cholesterol intolerance, collectively reflecting high evolutionary conservation of zebrafish Lxra function. Intestinal nr1h3 activation delays transport of absorbed neutral lipids, with accumulation of neutral lipids in enterocyte cytoplasmic droplets. This delay in transport of ingested neutral lipids protects animals from hypercholesterolemia and hepatic steatosis induced by a high-fat diet. On a gene regulatory level, Lxra induces expression of acsl3a, which encodes acyl-CoA synthetase long-chain family member 3a, a lipid droplet-anchored protein that directs fatty acyl chains into lipids. Forced overexpression of acls3a in enterocytes delays, in part, the appearance of neutral lipids in the vasculature of zebrafish larvae. Activation of Lxr in the intestine cell-autonomously regulates the rate of delivery of absorbed lipids by inducting a temporary lipid intestinal droplet storage depot.
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Affiliation(s)
- Lourdes Cruz-Garcia
- University of Utah Molecular Medicine (U2M2) Program,University of Utah, Salt Lake City, UT 84112 Department of Internal Medicine, Division of Endocrinology, Metabolism, and Diabetes,University of Utah, Salt Lake City, UT 84112
| | - Amnon Schlegel
- University of Utah Molecular Medicine (U2M2) Program,University of Utah, Salt Lake City, UT 84112 Department of Internal Medicine, Division of Endocrinology, Metabolism, and Diabetes,University of Utah, Salt Lake City, UT 84112 Department of Biochemistry, School of Medicine, University of Utah, Salt Lake City, UT 84112
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30
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Structure-dependent effects of pyridine derivatives on mechanisms of intestinal fatty acid uptake: regulation of nicotinic acid receptor and fatty acid transporter expression. J Nutr Biochem 2014; 25:750-7. [DOI: 10.1016/j.jnutbio.2014.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 03/02/2014] [Accepted: 03/04/2014] [Indexed: 11/23/2022]
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31
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Küch EM, Vellaramkalayil R, Zhang I, Lehnen D, Brügger B, Sreemmel W, Ehehalt R, Poppelreuther M, Füllekrug J. Differentially localized acyl-CoA synthetase 4 isoenzymes mediate the metabolic channeling of fatty acids towards phosphatidylinositol. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:227-39. [PMID: 24201376 DOI: 10.1016/j.bbalip.2013.10.018] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 09/20/2013] [Accepted: 10/14/2013] [Indexed: 02/06/2023]
Abstract
The acyl-CoA synthetase 4 (ACSL4) has been implicated in carcinogenesis and neuronal development. Acyl-CoA synthetases are essential enzymes of lipid metabolism, and ACSL4 is distinguished by its preference for arachidonic acid. Two human ACSL4 isoforms arising from differential splicing were analyzed by ectopic expression in COS cells. We found that the ACSL4_v1 variant localized to the inner side of the plasma membrane including microvilli, and was also present in the cytosol. ACSL4_v2 contains an additional N-terminal hydrophobic region; this isoform was located at the endoplasmic reticulum and on lipid droplets. A third isoform was designed de novo by appending a mitochondrial targeting signal. All three ACSL4 variants showed the same specific enzyme activity. Overexpression of the isoenzymes increased cellular uptake of arachidonate to the same degree, indicating that the metabolic trapping of fatty acids is independent of the subcellular localization. Remarkably, phospholipid metabolism was changed by ACSL4 expression. Labeling with arachidonate showed that the amount of newly synthesized phosphatidylinositol was increased by all three ACSL4 isoenzymes but not by ACSL1. This was dependent on the expression level and the localization of the ACSL4 isoform. We conclude that in our model system exogenous fatty acids are channeled preferentially towards phosphatidylinositol by ACSL4 overexpression. The differential localization of the endogenous isoenzymes may provide compartment specific precursors of this anionic phospholipid important for many signaling processes.
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32
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Pol A, Gross SP, Parton RG. Review: biogenesis of the multifunctional lipid droplet: lipids, proteins, and sites. ACTA ACUST UNITED AC 2014; 204:635-46. [PMID: 24590170 PMCID: PMC3941045 DOI: 10.1083/jcb.201311051] [Citation(s) in RCA: 335] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lipid droplets (LDs) are ubiquitous dynamic organelles that store and supply lipids in all eukaryotic and some prokaryotic cells for energy metabolism, membrane synthesis, and production of essential lipid-derived molecules. Interest in the organelle's cell biology has exponentially increased over the last decade due to the link between LDs and prevalent human diseases and the discovery of new and unexpected functions of LDs. As a result, there has been significant recent progress toward understanding where and how LDs are formed, and the specific lipid pathways that coordinate LD biogenesis.
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Affiliation(s)
- Albert Pol
- Equip de Compartiments Cellulars i Senyalització, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
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Abstract
The endothelium is often viewed solely as the barrier that prevents the penetration of circulating lipoproteins into the arterial wall. However, recent research has demonstrated that the endothelium has an important part in regulating circulating fatty acids and lipoproteins, and is in turn affected by these lipids/lipoproteins in ways that appear to have important repercussions for atherosclerosis. Thus, a number of potentially toxic lipids are produced during lipolysis of lipoproteins at the endothelial cell surface. Catabolism of triglyceride-rich lipoproteins creates free fatty acids that are readily taken up by endothelial cells, and, likely through the action of acyl-CoA synthetases, exacerbate inflammatory processes. In this article, we review how the endothelium participates in lipoprotein metabolism, how lipids alter endothelial functions, and how lipids are internalized, processed, and transported into the subendothelial space. Finally, we address the many endothelial changes that might promote atherogenesis, especially in the setting of diabetes.
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Affiliation(s)
- Ira J Goldberg
- Department of Medicine, Division of Preventive Medicine & Nutrition, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY, 10032, USA,
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34
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Kassan A, Herms A, Fernández-Vidal A, Bosch M, Schieber NL, Reddy BJN, Fajardo A, Gelabert-Baldrich M, Tebar F, Enrich C, Gross SP, Parton RG, Pol A. Acyl-CoA synthetase 3 promotes lipid droplet biogenesis in ER microdomains. ACTA ACUST UNITED AC 2014; 203:985-1001. [PMID: 24368806 PMCID: PMC3871434 DOI: 10.1083/jcb.201305142] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Acyl-CoA synthetase 3 is recruited early to lipid droplet assembly sites on the ER, where it is required for efficient lipid droplet nucleation and lipid storage. Control of lipid droplet (LD) nucleation and copy number are critical, yet poorly understood, processes. We use model peptides that shift from the endoplasmic reticulum (ER) to LDs in response to fatty acids to characterize the initial steps of LD formation occurring in lipid-starved cells. Initially, arriving lipids are rapidly packed in LDs that are resistant to starvation (pre-LDs). Pre-LDs are restricted ER microdomains with a stable core of neutral lipids. Subsequently, a first round of “emerging” LDs is nucleated, providing additional lipid storage capacity. Finally, in proportion to lipid concentration, new rounds of LDs progressively assemble. Confocal microscopy and electron tomography suggest that emerging LDs are nucleated in a limited number of ER microdomains after a synchronized stepwise process of protein gathering, lipid packaging, and recognition by Plin3 and Plin2. A comparative analysis demonstrates that the acyl-CoA synthetase 3 is recruited early to the assembly sites, where it is required for efficient LD nucleation and lipid storage.
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Affiliation(s)
- Adam Kassan
- Equip de Senyalització i Proliferació Cellular, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
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35
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Hagberg C, Mehlem A, Falkevall A, Muhl L, Eriksson U. Endothelial fatty acid transport: role of vascular endothelial growth factor B. Physiology (Bethesda) 2014; 28:125-34. [PMID: 23455771 DOI: 10.1152/physiol.00042.2012] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dietary lipids present in the circulation have to be transported through the vascular endothelium to be utilized by tissue cells, a vital mechanism that is still poorly understood. Vascular endothelial growth factor B (VEGF-B) regulates this process by controlling the expression of endothelial fatty acid transporter proteins (FATPs). Here, we summarize research on the role of the vascular endothelium in nutrient transport, with emphasis on VEGF-B signaling.
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36
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Melton EM, Cerny RL, DiRusso CC, Black PN. Overexpression of human fatty acid transport protein 2/very long chain acyl-CoA synthetase 1 (FATP2/Acsvl1) reveals distinct patterns of trafficking of exogenous fatty acids. Biochem Biophys Res Commun 2013; 440:743-8. [PMID: 24113382 DOI: 10.1016/j.bbrc.2013.09.137] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/26/2022]
Abstract
In mammals, the fatty acid transport proteins (FATP1 through FATP6) are members of a highly conserved family of proteins, which function in fatty acid transport proceeding through vectorial acylation and in the activation of very long chain fatty acids, branched chain fatty acids and secondary bile acids. FATP1, 2 and 4, for example directly function in fatty acid transport and very long chain fatty acids activation while FATP5 does not function in fatty acid transport but activates secondary bile acids. In the present work, we have used stable isotopically labeled fatty acids differing in carbon length and saturation in cells expressing FATP2 to gain further insights into how this protein functions in fatty acid transport and intracellular fatty acid trafficking. Our previous studies showed the expression of FATP2 modestly increased C16:0-CoA and C20:4-CoA and significantly increased C18:3-CoA and C22:6-CoA after 4h. The increases in C16:0-CoA and C18:3-CoA suggest FATP2 must necessarily partner with a long chain acyl CoA synthetase (Acsl) to generate C16:0-CoA and C18:3-CoA through vectorial acylation. The very long chain acyl CoA synthetase activity of FATP2 is consistent in the generation of C20:4-CoA and C22:6-CoA coincident with transport from their respective exogenous fatty acids. The trafficking of exogenous fatty acids into phosphatidic acid (PA) and into the major classes of phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidyserine (PS)) resulted in distinctive profiles, which changed with the expression of FATP2. The trafficking of exogenous C16:0 and C22:6 into PA was significant where there was 6.9- and 5.3-fold increased incorporation, respectively, over the control; C18:3 and C20:4 also trended to increase in the PA pool while there were no changes for C18:1 and C18:2. The trafficking of C18:3 into PC and PI trended higher and approached significance. In the case of C20:4, expression of FATP2 resulted in increases in all four classes of phospholipid, indicating little selectivity. In the case of C22:6, there were significant increases of this exogenous fatty acids being trafficking into PC and PI. Collectively, these data support the conclusion that FATP2 has a dual function in the pathways linking the transport and activation of exogenous fatty acids. We discuss the differential roles of FATP2 and its role in both fatty acid transport and fatty acid activation in the context of lipid homeostasis.
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Affiliation(s)
- Elaina M Melton
- Department of Biochemistry, University of Nebraska, Lincoln, NE, United States; Center for Cardiovascular Sciences, Albany Medical College, Albany, NY, United States
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Anderson CM, Stahl A. SLC27 fatty acid transport proteins. Mol Aspects Med 2013; 34:516-28. [PMID: 23506886 DOI: 10.1016/j.mam.2012.07.010] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/18/2012] [Indexed: 12/20/2022]
Abstract
The uptake and metabolism of long chain fatty acids (LCFA) are critical to many physiological and cellular processes. Aberrant accumulation or depletion of LCFA underlie the pathology of numerous metabolic diseases. Protein-mediated transport of LCFA has been proposed as the major mode of LCFA uptake and activation. Several proteins have been identified to be involved in LCFA uptake. This review focuses on the SLC27 family of fatty acid transport proteins, also known as FATPs, with an emphasis on the gain- and loss-of-function animal models that elucidate the functions of FATPs in vivo and how these transport proteins play a role in physiological and pathological situations.
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Affiliation(s)
- Courtney M Anderson
- Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California Berkeley, CA, USA
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Townsend KL, An D, Lynes MD, Huang TL, Zhang H, Goodyear LJ, Tseng YH. Increased mitochondrial activity in BMP7-treated brown adipocytes, due to increased CPT1- and CD36-mediated fatty acid uptake. Antioxid Redox Signal 2013; 19:243-57. [PMID: 22938691 PMCID: PMC3691916 DOI: 10.1089/ars.2012.4536] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AIMS Brown adipose tissue dissipates chemical energy in the form of heat and regulates triglyceride and glucose metabolism in the body. Factors that regulate fatty acid uptake and oxidation in brown adipocytes have not yet been fully elucidated. Bone morphogenetic protein 7 (BMP7) is a growth factor capable of inducing brown fat mitochondrial biogenesis during differentiation from adipocyte progenitors. Administration of BMP7 to mice also results in increased energy expenditure. To determine if BMP7 is able to affect the mitochondrial activity of mature brown adipocytes, independent of the differentiation process, we delivered BMP7 to mature brown adipocytes and measured mitochondrial activity. RESULTS We found that BMP7 increased mitochondrial activity, including fatty acid oxidation and citrate synthase activity, without increasing the mitochondrial number. This was accompanied by an increase in fatty acid uptake and increased protein expression of CPT1 and CD36, which import fatty acids into the mitochondria and the cell, respectively. Importantly, inhibition of either CPT1 or CD36 resulted in a blunting of the mitochondrial activity of BMP7-treated cells. INNOVATION These findings uncover a novel pathway regulating mitochondrial activities in mature brown adipocytes by BMP7-mediated fatty acid uptake and oxidation. CONCLUSION In conclusion, BMP7 increases mitochondrial activity in mature brown adipocytes via increased fatty acid uptake and oxidation, a process that requires the fatty acid transporters CPT1 and CD36.
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Affiliation(s)
- Kristy L Townsend
- Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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Li X, Gonzalez O, Shen X, Barnhart S, Kramer F, Kanter JE, Vivekanandan-Giri A, Tsuchiya K, Handa P, Pennathur S, Kim F, Coleman RA, Schaffer JE, Bornfeldt KE. Endothelial acyl-CoA synthetase 1 is not required for inflammatory and apoptotic effects of a saturated fatty acid-rich environment. Arterioscler Thromb Vasc Biol 2012; 33:232-40. [PMID: 23241406 DOI: 10.1161/atvbaha.112.252239] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Saturated fatty acids, such as palmitic and stearic acid, cause detrimental effects in endothelial cells and have been suggested to contribute to macrophage accumulation in adipose tissue and the vascular wall, in states of obesity and insulin resistance. Long-chain fatty acids are believed to require conversion into acyl-CoA derivatives to exert most of their detrimental effects, a reaction catalyzed by acyl-CoA synthetases (ACSLs). The objective of this study was to investigate the role of ACSL1, an ACSL isoform previously shown to mediate inflammatory effects in myeloid cells, in regulating endothelial cell responses to a saturated fatty acid-rich environment in vitro and in vivo. METHODS AND RESULTS Saturated fatty acids caused increased inflammatory activation, endoplasmic reticulum stress, and apoptosis in mouse microvascular endothelial cells. Forced ACSL1 overexpression exacerbated the effects of saturated fatty acids on apoptosis and endoplasmic reticulum stress. However, endothelial ACSL1 deficiency did not protect against the effects of saturated fatty acids in vitro, nor did it protect insulin-resistant mice fed a saturated fatty acid-rich diet from macrophage adipose tissue accumulation or increased aortic adhesion molecule expression. CONCLUSIONS Endothelial ACSL1 is not required for inflammatory and apoptotic effects of a saturated fatty acid-rich environment.
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Affiliation(s)
- Xin Li
- Departments of Pathology, University of Washington, Seattle WA, USA
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Softic S, Kirby M, Berger NG, Shroyer NF, Woods SC, Kohli R. Insulin concentration modulates hepatic lipid accumulation in mice in part via transcriptional regulation of fatty acid transport proteins. PLoS One 2012; 7:e38952. [PMID: 22745692 PMCID: PMC3380053 DOI: 10.1371/journal.pone.0038952] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 05/16/2012] [Indexed: 12/18/2022] Open
Abstract
Background Fatty liver disease (FLD) is commonly associated with insulin resistance and obesity, but interestingly it is also observed at low insulin states, such as prolonged fasting. Thus, we asked whether insulin is an independent modulator of hepatic lipid accumulation. Methods/Principal Findings In mice we induced, hypo- and hyperinsulinemia associated FLD by diet induced obesity and streptozotocin treatment, respectively. The mechanism of free fatty acid induced steatosis was studied in cell culture with mouse liver cells under different insulin concentrations, pharmacological phosphoinositol-3-kinase (PI3K) inhibition and siRNA targeted gene knock-down. We found with in vivo and in vitro models that lipid storage is increased, as expected, in both hypo- and hyperinsulinemic states, and that it is mediated by signaling through either insulin receptor substrate (IRS) 1 or 2. As previously reported, IRS-1 was up-regulated at high insulin concentrations, while IRS-2 was increased at low levels of insulin concentration. Relative increase in either of these insulin substrates, was associated with an increase in liver-specific fatty acid transport proteins (FATP) 2&5, and increased lipid storage. Furthermore, utilizing pharmacological PI3K inhibition we found that the IRS-PI3K pathway was necessary for lipogenesis, while FATP responses were mediated via IRS signaling. Data from additional siRNA experiments showed that knock-down of IRSs impacted FATP levels. Conclusions/Significance States of perturbed insulin signaling (low-insulin or high-insulin) both lead to increased hepatic lipid storage via FATP and IRS signaling. These novel findings offer a common mechanism of FLD pathogenesis in states of both inadequate (prolonged fasting) and ineffective (obesity) insulin signaling.
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Affiliation(s)
- Samir Softic
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, Riley Hospital for Children, Indiana University, Indianapolis, Indiana, United States of America
| | - Michelle Kirby
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Nicholas G. Berger
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Noah F. Shroyer
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Stephen C. Woods
- Metabolic Diseases Institute, Obesity Research Center, Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Rohit Kohli
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- * E-mail:
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Riedel A, Pignitter M, Hochkogler CM, Rohm B, Walker J, Bytof G, Lantz I, Somoza V. Caffeine dose-dependently induces thermogenesis but restores ATP in HepG2 cells in culture. Food Funct 2012; 3:955-64. [PMID: 22710994 DOI: 10.1039/c2fo30053b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Caffeine has been hypothesised as a thermogenic agent that might help to maintain a healthy body weight. Since very little is known about its actions on cellular energy metabolism, we investigated the effect of caffeine on mitochondrial oxidative phosphorylation, cellular energy supply and thermogenesis in HepG2 cells, and studied its action on fatty acid uptake and lipid accumulation in 3T3-L1 adipocytes at concentrations ranging from 30-1500 μM. In HepG2 cells, caffeine induced a depolarisation of the inner mitochondrial membrane, a feature of mitochondrial thermogenesis, both directly and after 24 h incubation. Increased concentrations of uncoupling protein-2 (UCP-2) also indicated a thermogenic activity of caffeine. Energy generating pathways, such as mitochondrial respiration, fatty acid oxidation and anaerobic lactate production, were attenuated by caffeine treatment. Nevertheless, HepG2 cells demonstrated a higher energy charge potential after exposure to caffeine that might result from energy restoration through attenuation of energy consuming pathways, as typically found in hibernating animals. In 3T3-L1 cells, in contrast, caffeine increased fatty acid uptake, but did not affect lipid accumulation. We provide evidence that caffeine stimulates thermogenesis but concomitantly causes energy restoration that may compensate enhanced energy expenditure.
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Affiliation(s)
- Annett Riedel
- Department of Nutritional and Physiological Chemistry, University of Vienna, Vienna, Austria
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Wadhwani NS, Manglekar RR, Dangat KD, Kulkarni AV, Joshi SR. Effect of maternal micronutrients (folic acid, vitamin B12) and omega 3 fatty acids on liver fatty acid desaturases and transport proteins in Wistar rats. Prostaglandins Leukot Essent Fatty Acids 2012; 86:21-7. [PMID: 22133376 DOI: 10.1016/j.plefa.2011.10.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 10/20/2011] [Accepted: 10/22/2011] [Indexed: 11/20/2022]
Abstract
A disturbed fatty acid metabolism increases the risk of adult non-communicable diseases. This study examines the effect of maternal micronutrients on the fatty acid composition, desaturase activity, mRNA levels of fatty acid desaturases and transport proteins in the liver. Pregnant female rats were divided into 6 groups at 2 levels of folic acid both in the presence and absence of vitamin B(12). The vitamin B(12) deficient groups were supplemented with omega 3 fatty acid. An imbalance of maternal micronutrients reduces liver docosahexaenoic acid, increases Δ5 desaturase activity but decreases mRNA levels, decreases Δ6 desaturase activity but not mRNA levels as compared to control. mRNA level of Δ5 desaturase reverts back to the levels of the control group as a result of omega 3 fatty acid supplementation. Our data for the first time indicates that maternal micronutrients differentially alter the activity and expression of fatty acid desaturases in the liver.
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Affiliation(s)
- Nisha S Wadhwani
- Interactive Research School for Health Affairs, Bharati Vidyapeeth University, Pune, India
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Lynes M, Narisawa S, Millán JL, Widmaier EP. Interactions between CD36 and global intestinal alkaline phosphatase in mouse small intestine and effects of high-fat diet. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1738-47. [PMID: 21900644 DOI: 10.1152/ajpregu.00235.2011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mechanisms of the saturable component of long-chain fatty acid (LCFA) transport across the small intestinal epithelium and its regulation by a high-fat diet (HFD) are uncertain. It is hypothesized here that the putative fatty acid translocase/CD36 and intestinal alkaline phosphatases (IAPs) function together to optimize LCFA transport. Phosphorylated CD36 (pCD36) was expressed in mouse enterocytes and dephosphorylated by calf IAP (CIAP). Uptake of fluorescently tagged LCFA into isolated enteroctyes was increased when cells were treated with CIAP; this was blocked with a specific CD36 inhibitor. pCD36 colocalized in enterocytes with the global IAP (gIAP) isozyme and, specifically, coimmunoprecipitated with gIAP, but not the duodenal-specific isozyme (dIAP). Purified recombinant gIAP dephosphorylated immunoprecipitated pCD36, and antiserum to gIAP decreased initial LCFA uptake in enterocytes. Body weight, adiposity, and plasma leptin and triglycerides were significantly increased in HFD mice compared with controls fed a normal-fat diet. HFD significantly increased immunoreactive CD36 and gIAP, but not dIAP, in jejunum, but not duodenum. Uptake of LCFA was increased in a CD36-dependent manner in enterocytes from HFD mice. It is concluded that CD36 exists in its phosphorylated and dephosphorylated states in mouse enterocytes, that pCD36 is a substrate of gIAP, and that dephosphorylation by IAPs results in increased LCFA transport capability. HFD upregulates CD36 and gIAP in parallel and enhances CD36-dependent fatty acid uptake. The interactions between these proteins may be important for efficient fat transport in mouse intestine, but whether the changes in gIAP and CD36 in enterocytes contribute to HFD-induced obesity remains to be determined.
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Affiliation(s)
- Matthew Lynes
- Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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Krammer J, Digel M, Ehehalt F, Stremmel W, Füllekrug J, Ehehalt R. Overexpression of CD36 and acyl-CoA synthetases FATP2, FATP4 and ACSL1 increases fatty acid uptake in human hepatoma cells. Int J Med Sci 2011; 8:599-614. [PMID: 22022213 PMCID: PMC3198256 DOI: 10.7150/ijms.8.599] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 09/27/2011] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Understanding the mechanisms of long chain fatty acid (LCFA) uptake in hepatic cells is of high medical importance to treat and to prevent fatty liver disease (FLD). ACSs (Acyl-CoA synthetases) are a family of enzymes that catalyze the esterification of fatty acids (FA) with CoA. Recent studies suggest that ACS enzymes drive the uptake of LCFA indirectly by their enzymatic activity and could promote special metabolic pathways dependent on their localization.The only protein located at the plasma membrane which has consistently been shown to enhance FA uptake is CD36. AIMS The current study investigated whether ACSs and CD36 could regulate hepatic LCFA uptake. METHODS AND RESULTS FATP2 and FATP4 were both localized to the ER of HuH7 and HepG2 cells as shown by double immunofluorescence in comparison to marker proteins. ACSL1 was located at mitochondria in both cell lines. Overexpression of FATP2, FATP4 and ACSL1 highly increased ACS activity as well as the uptake of [3H]-oleic acid and fluorescent Bodipy-C12 (B12) fatty acid. Quantitative FACS analysis showed a correlation between ACS expression levels and B12 uptake. FATP2 had the highest effect on B12 uptake of all proteins tested. CD36 was mainly localized at the plasma membrane. Whereas [3H]-oleic acid uptake was increased after overexpression, CD36 had no effect on B12 uptake. CONCLUSION Uptake of LCFA into hepatoma cells can be regulated by the expression levels of intracellular enzymes. We propose that ACS enzymes drive FA uptake indirectly by esterification. Therefore these molecules are potential targets for treatment of nonalcoholic fatty liver disease (NAFLD) or steatohepatitis (NASH).
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Affiliation(s)
- Julia Krammer
- Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
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Carley AN, Kleinfeld AM. Fatty acid (FFA) transport in cardiomyocytes revealed by imaging unbound FFA is mediated by an FFA pump modulated by the CD36 protein. J Biol Chem 2010; 286:4589-97. [PMID: 21147770 DOI: 10.1074/jbc.m110.182162] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Free fatty acid (FFA) transport across the cardiomyocyte plasma membrane is essential to proper cardiac function, but the role of membrane proteins and FFA metabolism in FFA transport remains unclear. Metabolism is thought to maintain intracellular FFA at low levels, providing the driving force for FFA transport, but intracellular FFA levels have not been measured directly. We report the first measurements of the intracellular unbound FFA concentrations (FFA(i)) in cardiomyocytes. The fluorescent indicator of FFA, ADIFAB (acrylodan-labeled rat intestinal fatty acid-binding protein), was microinjected into isolated cardiomyocytes from wild type (WT) and FAT/CD36 null C57B1/6 mice. Quantitative imaging of ADIFAB fluorescence revealed the time courses of FFA influx and efflux. For WT mice, rate constants for efflux (∼0.02 s(-1)) were twice influx, and steady state FFA(i) were more than 3-fold larger than extracellular unbound FFA (FFA(o)). The concentration gradient and the initial rate of FFA influx saturated with increasing FFA(o). Similar characteristics were observed for oleate, palmitate, and arachidonate. FAT/CD36 null cells revealed similar characteristics, except that efflux was 2-3-fold slower than WT cells. Rate constants determined with intracellular ADIFAB were confirmed by measurements of intracellular pH. FFA uptake by suspensions of cardiomyocytes determined by monitoring FFA(o) using extracellular ADIFAB confirmed the influx rate constants determined from FFA(i) measurements and demonstrated that rates of FFA transport and etomoxir-sensitive metabolism are regulated independently. We conclude that FFA influx in cardiac myocytes is mediated by a membrane pump whose transport rate constants may be modulated by FAT/CD36.
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Affiliation(s)
- Andrew N Carley
- Torrey Pines Institute for Molecular Studies, San Diego, California 92121, USA
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Lipid-induced up-regulation of human acyl-CoA synthetase 5 promotes hepatocellular apoptosis. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:1025-35. [PMID: 20470896 DOI: 10.1016/j.bbalip.2010.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 04/14/2010] [Accepted: 04/16/2010] [Indexed: 12/17/2022]
Abstract
In the pathogenesis of nonalcoholic fatty liver disease, accumulation of lipids in hepatocytes and hepatocyte apoptosis are strongly implicated in disease progression from the potentially reversible condition of steatosis to severe acute and chronic liver injury. Acyl-CoA synthetase 5, a member of the ACSL gene family that catalyzes the activation of long-chain fatty acids for lipid biosynthesis, is the only ACSL isoform that is both, located on mitochondria and functionally involved in enterocyte apoptosis. In this study, the regulation of human ACSL5 in hepatocellular fatty acid degeneration and its involvement in hepatocyte apoptosis was investigated using models of in vitro and in vivo steatosis as well as plasmid-mediated stable gene transfer and RNAi-mediated gene silencing. ACSL5 mRNA and protein were strongly increased by uptake of dietary derived fatty acids in primary human hepatocytes, HepG2 cells and human steatotic liver. Over-expression of ACSL5 decreased HepG2 cell viability and increased susceptibility to TRAIL- and TNFalpha-, but not FAS- induced apoptosis, whereas knock down of ACSL5 reduced apoptosis susceptibility. High ACSL5 activity resulted in enhanced caspase-3/7 activity, but was not accompanied by up-regulation of death receptors, DR4, DR5 or TNF-R1. This study gives evidence that hepatocyte steatosis is associated with ACSL5 up-regulation resulting in increased susceptibility to hepatic cell death. We propose that ACSL5 could play a role in promoting fatty acid-induced lipoapoptosis in hepatocytes as important mechanism in fatty liver-related disorders.
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Zhou W, Madrid P, Fluitt A, Stahl A, Xie XS. Development and validation of a high-throughput screening assay for human long-chain fatty acid transport proteins 4 and 5. ACTA ACUST UNITED AC 2010; 15:488-97. [PMID: 20448275 DOI: 10.1177/1087057110369700] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dietary long-chain fatty acid (LCFA) uptake across cell membranes is mediated principally by fatty acid transport proteins (FATPs). Six subtypes of this transporter are differentially expressed throughout the human and rodent body. To facilitate drugs discovery against FATP subtypes, the authors used mammalian cell lines stably expressing the recombinant human FATP4 and 5 and developed a high-throughput screening (HTS) assay using a 96-well fluorometric imaging plate reader (FLIPR). LCFA uptake signal-to-background ratios were between 3- and 5-fold. Two 4-aryl-dihydropyrimidinones, j3 and j5, produced inhibition of FATP4 with a half-maximal inhibitory concentration (IC(50)) of 0.21 and 0.63 microM, respectively, and displayed approximately 100-fold selectivity over FATP5. The US Drug Collection library was screened against the FATP5. A hit rate of around 0.4% was observed with a Z' factor of 0.6 +/- 0.2. Two confirmed hits are bile acids, chenodiol and ursodiol with an IC(50) of 2.4 and 0.22 microM, respectively. To increase throughput, a single time point measurement in a 384-well format was developed using the Analyst HT, and the results are comparable with the 96-well format. In conclusion, the FATP4 and 5 cell-based fluorescence assays are suitable for a primary drug screen, whereas differentiated cell lines are useful for a secondary drug screen.
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Affiliation(s)
- Wei Zhou
- Biosciences Division, SRI International, Menlo Park, CA 94063, USA
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Locke JA, Guns EST, Lehman ML, Ettinger S, Zoubeidi A, Lubik A, Margiotti K, Fazli L, Adomat H, Wasan KM, Gleave ME, Nelson CC. Arachidonic acid activation of intratumoral steroid synthesis during prostate cancer progression to castration resistance. Prostate 2010; 70:239-51. [PMID: 19790237 DOI: 10.1002/pros.21057] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND De novo androgen synthesis and subsequent androgen receptor (AR) activation has recently been shown to contribute to castration-resistant prostate cancer (CRPC) progression. Herein we provide evidence that fatty acids (FA) can trigger androgen synthesis within steroid starved prostate cancer (CaP) tumor cells. METHODS Tumoral FA and steroid levels were assessed by GC-MS and LC-MS, respectively. Profiles of genes and proteins involved in FA activation of steroidogenesis were assessed by fluorescence microscopy, immunohistochemistry, microarray expression profiling and Western blot analysis. RESULTS In human CaP tissues the levels of proteins responsible for FA activation of steroid synthesis were observed to be altered during progression to CRPC. Further investigating this mechanism in LNCaP cells, we demonstrate that specific FA, arachidonic acid, is synthesized in an androgen-dependent and AR-mediated manner. Arachidonic acid is known to induce steroidogenic acute regulatory protein (StAR) in steroidogenic cells. When bound to hormone sensitive lipase (HSL), StAR shuttles free cholesterol into the mitochondria for downstream conversion into androgens. We show that arachidonic acid induces androgen production in steroid starved LNCaP cells coincidently in the same conditions that HSL and StAR are predominantly localized in the mitochondria. Furthermore, their activities are verified by a functional increase in mitochondrial uptake of cholesterol in this steroid starved environment. CONCLUSIONS We propose that this characterized arachidonic acid induced steroidogenesis mechanism significantly contributes to the activation of AR in CRPC progression and therefore recommend that fatty acid pathways be targeted therapeutically in progressing CaP.
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Affiliation(s)
- Jennifer A Locke
- Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
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Glatz JFC, Luiken JJFP, Bonen A. Membrane Fatty Acid Transporters as Regulators of Lipid Metabolism: Implications for Metabolic Disease. Physiol Rev 2010; 90:367-417. [DOI: 10.1152/physrev.00003.2009] [Citation(s) in RCA: 515] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Long-chain fatty acids and lipids serve a wide variety of functions in mammalian homeostasis, particularly in the formation and dynamic properties of biological membranes and as fuels for energy production in tissues such as heart and skeletal muscle. On the other hand, long-chain fatty acid metabolites may exert toxic effects on cellular functions and cause cell injury. Therefore, fatty acid uptake into the cell and intracellular handling need to be carefully controlled. In the last few years, our knowledge of the regulation of cellular fatty acid uptake has dramatically increased. Notably, fatty acid uptake was found to occur by a mechanism that resembles that of cellular glucose uptake. Thus, following an acute stimulus, particularly insulin or muscle contraction, specific fatty acid transporters translocate from intracellular stores to the plasma membrane to facilitate fatty acid uptake, just as these same stimuli recruit glucose transporters to increase glucose uptake. This regulatory mechanism is important to clear lipids from the circulation postprandially and to rapidly facilitate substrate provision when the metabolic demands of heart and muscle are increased by contractile activity. Studies in both humans and animal models have implicated fatty acid transporters in the pathogenesis of diseases such as the progression of obesity to insulin resistance and type 2 diabetes. As a result, membrane fatty acid transporters are now being regarded as a promising therapeutic target to redirect lipid fluxes in the body in an organ-specific fashion.
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Affiliation(s)
- Jan F. C. Glatz
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; and Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Joost J. F. P. Luiken
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; and Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Arend Bonen
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; and Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
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Sandoval A, Chokshi A, Jesch ED, Black PN, Dirusso CC. Identification and characterization of small compound inhibitors of human FATP2. Biochem Pharmacol 2009; 79:990-9. [PMID: 19913517 DOI: 10.1016/j.bcp.2009.11.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/05/2009] [Accepted: 11/06/2009] [Indexed: 01/08/2023]
Abstract
Fatty acid transport proteins (FATPs) are bifunctional proteins, which transport long chain fatty acids into cells and activate very long chain fatty acids by esterification with coenzyme A. In an effort to understand the linkage between cellular fatty acid transport and the pathology associated with excessive accumulation of exogenous fatty acids, we targeted FATP-mediated fatty acid transport in a high throughput screen of more than 100,000 small diverse chemical compounds in yeast expressing human FATP2 (hsFATP2). Compounds were selected for their ability to depress the transport of the fluorescent long chain fatty acid analogue, C(1)-BODIPY-C(12). Among 234 hits identified in the primary screen, 5 compounds, each representative of a structural class, were further characterized in the human Caco-2 and HepG2 cell lines, each of which normally expresses FATP2, and in 3T3-L1 adipocytes, which do not. These compounds were effective in inhibiting uptake with IC(50)s in the low micromolar range in both Caco-2 and HepG2 cells. Inhibition of transport was highly specific for fatty acids and there were no effects of these compounds on cell viability, trans-epithelial electrical resistance, glucose transport, or long chain acyl-CoA synthetase activity. The compounds were less effective when tested in 3T3-L1 adipocytes suggesting selectivity of inhibition. These results suggest fatty acid transport can be inhibited in a FATP-specific manner without causing cellular toxicity.
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Affiliation(s)
- Angel Sandoval
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
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