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Downing LE, Heidker RM, Caiozzi GC, Wong BS, Rodriguez K, Del Rey F, Ricketts ML. A Grape Seed Procyanidin Extract Ameliorates Fructose-Induced Hypertriglyceridemia in Rats via Enhanced Fecal Bile Acid and Cholesterol Excretion and Inhibition of Hepatic Lipogenesis. PLoS One 2015; 10:e0140267. [PMID: 26458107 PMCID: PMC4601771 DOI: 10.1371/journal.pone.0140267] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/22/2015] [Indexed: 12/31/2022] Open
Abstract
The objective of this study was to determine whether a grape seed procyanidin extract (GSPE) exerts a triglyceride-lowering effect in a hyperlipidemic state using the fructose-fed rat model and to elucidate the underlying molecular mechanisms. Rats were fed either a starch control diet or a diet containing 65% fructose for 8 weeks to induce hypertriglyceridemia. During the 9th week of the study, rats were maintained on their respective diet and administered vehicle or GSPE via oral gavage for 7 days. Fructose increased serum triglyceride levels by 171% after 9 weeks, compared to control, while GSPE administration attenuated this effect, resulting in a 41% decrease. GSPE inhibited hepatic lipogenesis via down-regulation of sterol regulatory element binding protein 1c and stearoyl-CoA desaturase 1 in the fructose-fed animals. GSPE increased fecal bile acid and total lipid excretion, decreased serum bile acid levels and increased the expression of genes involved in cholesterol synthesis. However, bile acid biosynthetic gene expression was not increased in the presence of GSPE and fructose. Serum cholesterol levels remained constant, while hepatic cholesterol levels decreased. GSPE did not modulate expression of genes responsible for esterification or biliary export of the newly synthesized cholesterol, but did increase fecal cholesterol excretion, suggesting that in the presence of GSPE and fructose, the liver may secrete more free cholesterol into the plasma which may then be shunted to the proximal small intestine for direct basolateral to apical secretion and subsequent fecal excretion. Our results demonstrate that GSPE effectively lowers serum triglyceride levels in fructose-fed rats after one week administration. This study provides novel insight into the mechanistic actions of GSPE in treating hypertriglyceridemia and demonstrates that it targets hepatic de novo lipogenesis, bile acid homeostasis and non-biliary cholesterol excretion as important mechanisms for reducing hypertriglyceridemia and hepatic lipid accumulation in the presence of fructose.
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Affiliation(s)
- Laura E. Downing
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Rebecca M. Heidker
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Gianella C. Caiozzi
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Brian S. Wong
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Kelvin Rodriguez
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Fernando Del Rey
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Marie-Louise Ricketts
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
- * E-mail:
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102
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Ilavenil S, Kim DH, Valan Arasu M, Srigopalram S, Sivanesan R, Choi KC. Phenyllactic Acid from Lactobacillus plantarum PromotesAdipogenic Activity in 3T3-L1 Adipocyte via Up-Regulationof PPAR-γ2. Molecules 2015; 20:15359-73. [PMID: 26305241 PMCID: PMC6332376 DOI: 10.3390/molecules200815359] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 11/16/2022] Open
Abstract
Synthetic drugs are commonly used to cure various human ailments at present. However, the uses of synthetic drugs are strictly regulated because of their adverse effects. Thus, naturally occurring molecules may be more suitable for curing disease without unfavorable effects. Therefore, we investigated phenyllactic acid (PLA) from Lactobacillus plantarum with respect to its effects on adipogenic genes and their protein expression in 3T3-L1 pre-adipocytes by qPCR and western blot techniques. PLA enhanced differentiation and lipid accumulation in 3T3-L1 cells at the concentrations of 25, 50, and 100 μM. Maximum differentiation and lipid accumulation were observed at a concentration of 100 μM of PLA, as compared with control adipocytes (p < 0.05). The mRNA and protein expression of PPAR-γ2, C/EBP-α, adiponectin, fatty acid synthase (FAS), and SREBP-1 were increased by PLA treatment as compared with control adipocytes (p < 0.05). PLA stimulates PPAR-γ mRNA expression in a concentration dependent manner, but this expression was lesser than agonist (2.83 ± 0.014 fold) of PPAR-γ2. Moreover, PLA supplementation enhances glucose uptake in 3T3-L1 pre-adipocytes (11.81 ± 0.17 mM) compared to control adipocytes, but this glucose uptake was lesser than that induced by troglitazone (13.75 ± 0.95 mM) and insulin treatment (15.49 ± 0.20 mM). Hence, we conclude that PLA treatment enhances adipocyte differentiation and glucose uptake via activation of PPAR-γ2, and PLA may thus be the potential candidate for preventing Type 2 Diabetes Mellitus (T2DM).
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Affiliation(s)
- Soundharrajan Ilavenil
- Grassland and Forage Division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330801, Korea.
| | - Da Hye Kim
- The United Graduate School of Agricultural Sciences, Tottori University, Tottori-Shi 6808553, Japan.
| | - Mariadhas Valan Arasu
- Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia.
| | - Srisesharam Srigopalram
- Grassland and Forage Division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330801, Korea.
| | | | - Ki Choon Choi
- Grassland and Forage Division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330801, Korea.
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103
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Ferulic acid regulates hepatic GLUT2 gene expression in high fat and fructose-induced type-2 diabetic adult male rat. Eur J Pharmacol 2015; 761:391-7. [DOI: 10.1016/j.ejphar.2015.04.043] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 04/20/2015] [Indexed: 11/22/2022]
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104
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Kim DH, Choi KC, Ichinohe T, Song SH. Effects of different roughage sources and feeding levels on adipogenesis of ovine adipocytes. Anim Sci J 2015; 86:943-51. [PMID: 26153850 DOI: 10.1111/asj.12380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/18/2014] [Indexed: 11/29/2022]
Abstract
The objective of the present study was to conduct an adipogenic evaluation of different roughage sources and feeding levels during ruminant adipocyte differentiation in vitro. Six wether sheep were divided into a timothy hay feeding group (TFG, n = 3) and an Italian ryegrass straw feeding group (IFG, n = 3). The sheep were fed high-roughage (HR), medium roughage (MR) and low-roughage (LR) diets in a one-way layout design each over a 6-day period. Sheep serum samples collected on the last day of each dietary treatment were added to an adipogenic induction medium for differentiation of preadipocytes derived from sheep subcutaneous adipose tissue. The cytoplasmic lipid accumulations in the TFG serum-treated preadipocytes were significantly higher than those of the IFG-serum treated preadipocytes on day 12. Messenger RNA expression of CCAAT/enhancer-binding protein (C/EBP)-α, C/EBP-β, C/EBP-δ, fatty-acid-binding protein (aP2) and stearoyl-coenzyme A desaturase (SCD) were regulated by each serum treatment. This study shows that different roughage source diets and roughage-to-concentrate ratio diets can regulate adipocyte differentiation via ruminant blood composition.
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Affiliation(s)
- Da-Hye Kim
- Faculty of Life and Environmental Science, Shimane University, Matsue, Japan.,The United Graduate School of Agricultural Sciences, Tottori University, Tottori, Japan
| | - Ki-Choon Choi
- Grassland and Forage Division, National Institute of Animal Science, RDA, Chungnam, Republic of Korea
| | - Toshiyoshi Ichinohe
- Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Sang-Houn Song
- Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
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105
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Regulation of Adipogenesis and Key Adipogenic Gene Expression by 1, 25-Dihydroxyvitamin D in 3T3-L1 Cells. PLoS One 2015; 10:e0126142. [PMID: 26030589 PMCID: PMC4451075 DOI: 10.1371/journal.pone.0126142] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/30/2015] [Indexed: 01/22/2023] Open
Abstract
The functions of 1, 25-dihydroxyvitamin D (1, 25-(OH)2D3) in regulating adipogenesis, adipocyte differentiation and key adipogenic gene expression were studied in 3T3-L1 preadipocytes. Five concentrations (0.01, 0.1, 1, 10, 100nM) of 1, 25-(OH)2D3 were studied and lipid accumulation measured by Oil Red O staining and expression of adipogenic genes quantified using quantitative real-time PCR. Adipogenic responses to 1, 25-(OH)2D3 were determined on 6, and 12 h, and days 1-10 after induction of adipogenesis by a hormonal cocktail with or without 1, 25-(OH)2D3. In response to 1, 25-(OH)2D3 (1, 10, and 100 nM), lipid accumulation and the expression of PPARγ, C/EBPα, FABP4 and SCD-1 were inhibited through day 10, and vitamin D receptor expression was inhibited in the early time points. The greatest inhibitory effect was upon expression of FABP4. Expression of SREBP-1c was only affected on day 2. The lowest concentrations of 1, 25-(OH)2D3 tested did not affect adipocyte differentiation or adipogenic gene expression. The C/EBPα promoter activity response to 1, 25-(OH)2D3 was also tested, with no effect detected. These results indicate that 1, 25-(OH)2D3 inhibited adipogenesis via suppressing adipogenic-specific genes, and is invoked either during PPARγ activation or immediately up-stream thereof. Gene expression down-stream of PPARγ especially FABP4 was strongly inhibited, and we suggest that the role of 1, 25-(OH)2D3 in regulating adipogenesis will be informed by further studies of adipogenic-specific gene promoter activity.
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106
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Yin X, Huang Y, Jung DW, Chung HC, Choung SY, Shim JH, Kang IJ. Anti-Diabetic Effect of Aster sphathulifolius in C57BL/KsJ-db/db Mice. J Med Food 2015; 18:987-98. [PMID: 25961463 DOI: 10.1089/jmf.2014.3416] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this study, we investigated the anti-diabetic effect of Aster sphathulifolius (AS) extract in C57BL/KsJ-db/db mice. The db/db mice were orally administered with AS 50% ethanol extract at concentrations of 50, 100, and 200 mg/kg/day (db/db-AS50, db/db-AS100, and db/db-AS200, respectively) for 10 weeks. Food and water intake, fasting blood glucose concentrations, blood glycosylated hemoglobin levels, and plasma insulin levels were significantly lower in the db/db-AS200 group than in the vehicle-treated db/db group; whereas glucose tolerance was significantly improved in the db/db-AS200 group. Moreover, AS dose dependently increased both insulin receptor substrate 1 and glucose transporter type 4 expression in skeletal muscle, significantly increased glucokinase expression, and decreased glucose 6-phosphatase and phosphoenolpyruvate carboxykinase expressions in the liver. The expressions of transcription factors, such as sterol-regulatory element-binding protein, peroxisome proliferator-activated receptor γ, and adipocyte protein 2, were upregulated in adipose tissue. Furthermore, immunohistochemical analysis showed that AS upregulated insulin production by increasing pancreatic β-cell mass. In summary, AS extract normalized hyperglycemia by multiple mechanisms: inhibition of glyconeogenesis, acceleration of glucose metabolism and lipid metabolism, and increase of glucose uptake. Using in vivo assays, this study has shown the potential of AS as a medicinal food and suggests the efficacy of AS for the use of prevention of diabetes.
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Affiliation(s)
- Xingfu Yin
- 1 Department of Food Science and Nutrition, Hallym University , Gwangwon, Korea
| | - Yuhua Huang
- 1 Department of Food Science and Nutrition, Hallym University , Gwangwon, Korea
| | - Da-Woon Jung
- 1 Department of Food Science and Nutrition, Hallym University , Gwangwon, Korea
| | | | - Se Young Choung
- 3 Department of Preventive Pharmacy and Toxicology, College of Pharmacy, Kyung Hee University , Seoul, Korea
| | - Jae-Hoon Shim
- 1 Department of Food Science and Nutrition, Hallym University , Gwangwon, Korea
| | - Il-Jun Kang
- 1 Department of Food Science and Nutrition, Hallym University , Gwangwon, Korea
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107
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Lv Z, Chu Y, Wang Y. HIV protease inhibitors: a review of molecular selectivity and toxicity. HIV AIDS-RESEARCH AND PALLIATIVE CARE 2015; 7:95-104. [PMID: 25897264 PMCID: PMC4396582 DOI: 10.2147/hiv.s79956] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Highly active antiretroviral therapy (HAART) is recognized as the most effective treatment method for AIDS, and protease inhibitors play a very important role in HAART. However, poor bioavailability and unbearable toxicity are their common disadvantages. Thus, the development of safer and potentially promising protease inhibitors is eagerly needed. In this review, we introduced the chemical characteristics and associated side effects of HIV protease inhibitors, as well as the possible off-target mechanisms causing the side effects. From the chemical structures of HIV protease inhibitors and their possible off-target molecules, we could obtain hints for optimizing the molecular selectivity of the inhibitors, to provide help in the design of new compounds with enhanced bioavailability and reduced side effects.
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Affiliation(s)
- Zhengtong Lv
- Department of Immunology, School of Basic Medical Science, Xiangya School of Medicine, Central South University, Changsha, Hunan, People's Republic of China
| | - Yuan Chu
- Department of Immunology, School of Basic Medical Science, Xiangya School of Medicine, Central South University, Changsha, Hunan, People's Republic of China
| | - Yong Wang
- Department of Immunology, School of Basic Medical Science, Xiangya School of Medicine, Central South University, Changsha, Hunan, People's Republic of China
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108
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Li J, Luo J, Xu H, Wang M, Zhu J, Shi H, Haile AB, Wang H, Sun Y. Fatty acid synthase promoter: Characterization, and transcriptional regulation by sterol regulatory element binding protein-1 in goat mammary epithelial cells. Gene 2015; 561:157-64. [DOI: 10.1016/j.gene.2015.02.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/22/2015] [Accepted: 02/12/2015] [Indexed: 12/18/2022]
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109
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Shen Q, Riedl KM, Cole RM, Lehman C, Xu L, Alder H, Belury MA, Schwartz SJ, Ziouzenkova O. Egg yolks inhibit activation of NF-κB and expression of its target genes in adipocytes after partial delipidation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:2013-25. [PMID: 25620076 PMCID: PMC4362627 DOI: 10.1021/jf5056584] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
How composition of egg yolk (EY) influences NF-κB, a key transcription pathway in inflammation, remains unclear. We performed partial delipidation of EY that removed 20-30% of cholesterol and triglycerides. The resulting polar and nonpolar fractions were termed EY-P and EY-NP. NF-κB activation in response to EY from different suppliers and their fractions was examined in 3T3-L1 adipocytes using a NF-κB response element reporter assay and by analyzing expression of 248 inflammatory genes. Although EY-P and EY contained similar level of vitamins, carotenoids, and fatty acids, only delipidated EY-P fraction suppressed NF-κB via down-regulation of toll like receptor-2 and up-regulation of inhibitory toll interacting protein (Tollip) and lymphocyte antigen 96 (Ly96). Our data suggest that anti-inflammatory activity of lutein and retinol were blunted by nonpolar lipids in EY, likely via crosstalk between SREBP and NF-κB pathways in adipocytes. Thus, moderate delipidation may improve the beneficial properties of regular eggs.
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Affiliation(s)
- Qiwen Shen
- Department of Human Sciences, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Ken M. Riedl
- Department of Food Science and Technology, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Rachel M. Cole
- Department of Human Sciences, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Christopher Lehman
- Department of Human Sciences, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Lu Xu
- Department of Human Sciences, The Ohio State University, Columbus, Ohio, 43210, USA
- Division of Minimally Invasive Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Hansjuerg Alder
- Nucleic Acid Shared Resource, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Martha A. Belury
- Department of Human Sciences, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Steven J. Schwartz
- Department of Food Science and Technology, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Ouliana Ziouzenkova
- Department of Human Sciences, The Ohio State University, Columbus, Ohio, 43210, USA
- Corresponding author: O.Z., 1787 Neil Avenue, 331A Campbell Hall, Columbus, OH, 43210, , Telephone: 614 292 5034, Fax: 614 292 8880
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110
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Dasgupta S, Putluri N, Long W, Zhang B, Wang J, Kaushik AK, Arnold JM, Bhowmik SK, Stashi E, Brennan CA, Rajapakshe K, Coarfa C, Mitsiades N, Ittmann MM, Chinnaiyan AM, Sreekumar A, O'Malley BW. Coactivator SRC-2-dependent metabolic reprogramming mediates prostate cancer survival and metastasis. J Clin Invest 2015; 125:1174-88. [PMID: 25664849 DOI: 10.1172/jci76029] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 01/02/2015] [Indexed: 12/19/2022] Open
Abstract
Metabolic pathway reprogramming is a hallmark of cancer cell growth and survival and supports the anabolic and energetic demands of these rapidly dividing cells. The underlying regulators of the tumor metabolic program are not completely understood; however, these factors have potential as cancer therapy targets. Here, we determined that upregulation of the oncogenic transcriptional coregulator steroid receptor coactivator 2 (SRC-2), also known as NCOA2, drives glutamine-dependent de novo lipogenesis, which supports tumor cell survival and eventual metastasis. SRC-2 was highly elevated in a variety of tumors, especially in prostate cancer, in which SRC-2 was amplified and overexpressed in 37% of the metastatic tumors evaluated. In prostate cancer cells, SRC-2 stimulated reductive carboxylation of α-ketoglutarate to generate citrate via retrograde TCA cycling, promoting lipogenesis and reprogramming of glutamine metabolism. Glutamine-mediated nutrient signaling activated SRC-2 via mTORC1-dependent phosphorylation, which then triggered downstream transcriptional responses by coactivating SREBP-1, which subsequently enhanced lipogenic enzyme expression. Metabolic profiling of human prostate tumors identified a massive increase in the SRC-2-driven metabolic signature in metastatic tumors compared with that seen in localized tumors, further implicating SRC-2 as a prominent metabolic coordinator of cancer metastasis. Moreover, SRC-2 inhibition in murine models severely attenuated the survival, growth, and metastasis of prostate cancer. Together, these results suggest that the SRC-2 pathway has potential as a therapeutic target for prostate cancer.
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111
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Human cancer: Is it linked to dysfunctional lipid metabolism? Biochim Biophys Acta Gen Subj 2015; 1850:352-64. [DOI: 10.1016/j.bbagen.2014.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/27/2014] [Accepted: 11/03/2014] [Indexed: 11/23/2022]
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112
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Oliveira DM, Chalfun-Junior A, Chizzotti ML, Barreto HG, Coelho TC, Paiva LV, Coelho CP, Teixeira PD, Schoonmaker JP, Ladeira MM. Expression of genes involved in lipid metabolism in the muscle of beef cattle fed soybean or rumen-protected fat, with or without monensin supplementation. J Anim Sci 2014; 92:5426-36. [PMID: 25403202 DOI: 10.2527/jas.2014-7855] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Degree of unsaturation of fatty acids, which is influenced by lipid source and level of metabolism in the rumen, is a major determinant in how dietary lipids affect genes that regulate beef marbling. A total of 28 Red Norte bulls with an initial live weight of 361±32 kg (P>0.05) were used in a completely randomized experimental design to analyze the expression of genes that are involved in lipid metabolism in the longissimus dorsi (LD) when diets contained soybean grain or rumen-protected fat, with or without monensin. Treatments were arranged as a 2×2 factorial, with 4 treatments and 7 replicates per treatment. Half of the animals that received soybean or rumen-protected fat were supplemented with 230 mg head(-1) d(-1) of monensin. Gene expression was analyzed by reverse-transcription quantitative PCR (RT-qPCR). Expression of sterol regulatory element-binding protein-1c (SREBP-1c) in the LD muscle was not affected by lipid source or monensin (P>0.05). There was an interaction effect (P<0.05) between lipid source and monensin for peroxisome proliferator-activated receptor α (PPAR-α) and stearoyl-CoA desaturase (SCD) expression, where greater gene expression was found in animals fed soybean plus monensin and the lower gene expression was found in animals fed rumen-protected fat plus monensin. Expression of lipoprotein lipase (LPL) and fatty acid-binding protein 4 (FABP4) were greater (P<0.05) in the LD muscle of animals fed soybean. Monensin had no effect on LPL and FABP4 expression when soybean without monensin was fed, but when rumen-protected fat was fed, monensin increased LPL expression and decreased FABP4 expression (P<0.05). Linoleic and arachidonic acids had negative correlations (P<0.05) with the expression of PPAR-α, SCD, FABP4, and LPL genes. PPAR-α gene expression was not correlated with SREBP-1c but was positively correlated with SCD, FABP4, LPL, and glutathione peroxidase (GPX1) gene expression (P<0.001). Lipid sources and monensin interact and alter the expression of PPAR-α, SCD, acetyl CoA carboxylase α (ACACA), LPL, FABP4, and GPX1. These changes in gene expression were most associated with arachidonic and α-linolenic acids and the ability of lipid sources and monensin to increase these fatty acids in tissues.
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Affiliation(s)
- D M Oliveira
- Department of Animal Science, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
| | - A Chalfun-Junior
- Department of Biology, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
| | - M L Chizzotti
- Department of Animal Science, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil, 36.570-000
| | - H G Barreto
- Department of Agricultural Sciences, Universidade Federal de Tocantins, Gurupi, Tocantins, Brazil, 77.402-970
| | - T C Coelho
- Department of Animal Science, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
| | - L V Paiva
- Department of Chemistry, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
| | - C P Coelho
- Department of Animal Science, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
| | - P D Teixeira
- Department of Animal Science, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
| | - J P Schoonmaker
- Department of Animal Science, Purdue University, West Lafayette, IN 47906
| | - M M Ladeira
- Department of Animal Science, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil, 37.200-000
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113
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Abstract
Accumulation of triacylglycerols within the cytoplasm of hepatocytes to the degree that lipid droplets are visible microscopically is called liver steatosis. Most commonly, it occurs when there is an imbalance between the delivery or synthesis of fatty acids in the liver and their disposal through oxidative pathways or secretion into the blood as a component of triacylglycerols in very low density lipoprotein. This disorder is called nonalcoholic fatty liver disease (NAFLD) in the absence of alcoholic abuse and viral hepatitis, and it is often associated with insulin resistance, obesity and type 2 diabetes. Also, liver steatosis can be induced by many other causes including excessive alcohol consumption, infection with genotype 3 hepatitis C virus and certain medications. Whereas hepatic triacylglycerol accumulation was once considered the ultimate effector of hepatic lipotoxicity, triacylglycerols per se are quite inert and do not induce insulin resistance or cellular injury. Rather, lipotoxic injury in the liver appears to be mediated by the global ongoing fatty acid enrichment in the liver, paralleling the development of insulin resistance. A considerable number of fatty acid metabolites may be responsible for hepatic lipotoxicity and liver injury. Additional key contributors include hepatic cytosolic lipases and the "lipophagy" of lipid droplets, as sources of hepatic fatty acids. The specific origin of the lipids, mainly triacylglycerols, accumulating in liver has been unraveled by recent kinetic studies, and identifying the origin of the accumulated triacylglycerols in the liver of patients with NAFLD may direct the prevention and treatment of this condition.
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Affiliation(s)
- David Q-H Wang
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St. Louis, Missouri
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114
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Ding F, Yuan X, Li Q, Sun W, Gan C, He H, Song C, Wang J. Cloning, characterization and expression of Peking duck fatty acid synthase during adipocyte differentiation. ELECTRON J BIOTECHN 2014. [DOI: 10.1016/j.ejbt.2014.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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115
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Effects of yerba maté, a plant extract formulation ("YGD") and resveratrol in 3T3-L1 adipogenesis. Molecules 2014; 19:16909-24. [PMID: 25338179 PMCID: PMC6271528 DOI: 10.3390/molecules191016909] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/24/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022] Open
Abstract
We aimed to evaluate the in vitro effects of yerba maté, YGD (a herbal preparation containing yerba maté, guarana and damiana), and resveratrol on adipogenesis. The anti-adipogenic effects of yerba mate, YGD, resveratrol and YGD + resveratrol and yerba mate + resveratrol combinations were evaluated in 3T3-L1 cells by Oil Red staining, cellular triglyceride content, and PCR quantitative array. The results demonstrated that all of the tested compounds inhibited adipogenesis. Yerba maté extract significantly down-regulated the expression of genes that play an important role in regulating adipogenesis, such as Adig, Axin, Cebpa, Fgf10, Lep, Lpl, and Pparγ2. In addition, these genes, YGD also repressed Bmp2, Ccnd1, Fasn, and Srebf1. Resveratrol also modulated the expression of Adig, Bmp2, Ccnd1, C/EBPα, Fasn, Fgf10, Lep, Lpl, and Pparγ2. Moreover, resveratrol repressed Cebpb, Cdk4, Fgf2, and Klf15. The yerba maté extract and YGD up-regulated the expression of genes involved in inhibiting adipogenesis, such as Dlk-1, Klf2, and Ucp1. Resveratrol also induced the expression of Klf2 and Ucp1. In addition resveratrol modulated the Ddit3, Foxo1, Sirt1, and Sirt2. The combined effects of these compounds on gene expression showed similar results observed from individual treatments. Our data indicates that the synergy between the compounds favors the inhibition of adipogenesis.
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Horbach T, Chi TF, Götz C, Sharma S, Juffer AH, Dimova EY, Kietzmann T. GSK3β-dependent phosphorylation alters DNA binding, transactivity and half-life of the transcription factor USF2. PLoS One 2014; 9:e107914. [PMID: 25238393 PMCID: PMC4169611 DOI: 10.1371/journal.pone.0107914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/21/2014] [Indexed: 12/13/2022] Open
Abstract
The upstream stimulatory factor 2 (USF2) is a regulator of important cellular processes and is supposed to have also a role during tumor development. However, the knowledge about the mechanisms that control the function of USF2 is limited. The data of the current study show that USF2 function is regulated by phosphorylation and identified GSK3β as an USF2-phosphorylating kinase. The phosphorylation sites within USF2 could be mapped to serine 155 and threonine 230. In silico analyses of the 3-dimensional structure revealed that phosphorylation of USF2 by GSK3β converts it to a more open conformation which may influence transactivity, DNA binding and target gene expression. Indeed, experiments with GSK-3β-deficient cells revealed that USF2 transactivity, DNA binding and target gene expression were reduced upon lack of GSK3β. Further, experiments with USF2 variants mimicking GSK3β phosphorylated USF2 in GSK3β-deficient cells showed that phosphorylation of USF2 by GSK3β did not affect cell proliferation but increased cell migration. Together, this study reports a new mechanism by which USF2 may contribute to cancerogenesis.
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Affiliation(s)
- Tina Horbach
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
- Department of Chemistry, University of Kaiserslautern, Kaiserslautern, Germany
| | - Tabughang Franklin Chi
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Satyan Sharma
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - André H. Juffer
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Elitsa Y. Dimova
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Thomas Kietzmann
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
- * E-mail:
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Lee JH, Lee GY, Jang H, Choe SS, Koo SH, Kim JB. Ring finger protein20 regulates hepatic lipid metabolism through protein kinase A-dependent sterol regulatory element binding protein1c degradation. Hepatology 2014; 60:844-57. [PMID: 24425205 PMCID: PMC4258077 DOI: 10.1002/hep.27011] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 01/09/2014] [Indexed: 12/07/2022]
Abstract
UNLABELLED Sterol regulatory element binding protein1c (SREBP1c) is a key transcription factor for de novo lipogenesis during the postprandial state. During nutritional deprivation, hepatic SREBP1c is rapidly suppressed by fasting signals to prevent lipogenic pathways. However, the molecular mechanisms that control SREBP1c turnover in response to fasting status are not thoroughly understood. To elucidate which factors are involved in the inactivation of SREBP1c, we attempted to identify SREBP1c-interacting proteins by mass spectrometry analysis. Since we observed that ring finger protein20 (RNF20) ubiquitin ligase was identified as one of SREBP1c-interacting proteins, we hypothesized that fasting signaling would promote SREBP1c degradation in an RNF20-dependent manner. In this work, we demonstrate that RNF20 physically interacts with SREBP1c, leading to degradation of SREBP1c via ubiquitination. In accordance with these findings, RNF20 represses the transcriptional activity of SREBP1c and turns off the expression of lipogenic genes that are targets of SREBP1c. In contrast, knockdown of RNF20 stimulates the expression of SREBP1c and lipogenic genes and induces lipogenic activity in primary hepatocytes. Furthermore, activation of protein kinase A (PKA) with glucagon or forskolin enhances the expression of RNF20 and potentiates the ubiquitination of SREBP1c via RNF20. In wild-type and db/db mice, adenoviral overexpression of RNF20 markedly suppresses FASN promoter activity and reduces the level of hepatic triglycerides, accompanied by a decrease in the hepatic lipogenic program. Here, we reveal that RNF20-induced SREBP1c ubiquitination down-regulates hepatic lipogenic activity upon PKA activation. CONCLUSION RNF20 acts as a negative regulator of hepatic fatty acid metabolism through degradation of SREBP1c upon PKA activation. Knowledge regarding this process enhances our understanding of how SREBP1c is able to turn off hepatic lipid metabolism during nutritional deprivation.
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Affiliation(s)
- Jae Ho Lee
- School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National UniversitySeoul, Korea
| | - Gha Young Lee
- School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National UniversitySeoul, Korea
| | - Hagoon Jang
- School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National UniversitySeoul, Korea
| | - Sung Sik Choe
- School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National UniversitySeoul, Korea
| | - Seung-Hoi Koo
- Department of Life Sciences, Korea UniversitySeoul, Korea
| | - Jae Bum Kim
- School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National UniversitySeoul, Korea
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Zhang J, Liu F. Tissue-specific insulin signaling in the regulation of metabolism and aging. IUBMB Life 2014; 66:485-95. [PMID: 25087968 DOI: 10.1002/iub.1293] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/14/2014] [Indexed: 12/30/2022]
Abstract
In mammals, insulin signaling regulates glucose homeostasis and plays an essential role in metabolism, organ growth, development, fertility, and lifespan. The defects in this signaling pathway contribute to various metabolic diseases such as type 2 diabetes, polycystic ovarian disease, hypertension, hyperlipidemia, and atherosclerosis. However, reducing the insulin signaling pathway has been found to increase longevity and delay the aging-associated diseases in various animals, ranging from nematodes to mice. These seemly paradoxical findings raise an interesting question as to how modulation of the insulin signaling pathway could be an effective approach to improve metabolism and aging. In this review, we summarize current understanding on tissue-specific functions of insulin signaling in the regulation of metabolism and lifespan. We also discuss the potential benefits and limitations in modulating tissue-specific insulin signaling pathway to improve metabolism and healthspan.
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Affiliation(s)
- Jingjing Zhang
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education; Diabetes Center, Institute of Metabolism and Endocrinology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
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Fitzsimons C, Kenny DA, Waters SM, Earley B, McGee M. Effects of phenotypic residual feed intake on response to a glucose tolerance test and gene expression in the insulin signaling pathway in longissimus dorsi in beef cattle. J Anim Sci 2014; 92:4616-31. [PMID: 25085393 DOI: 10.2527/jas.2014-7699] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The objectives of this study were to determine the insulinogenic response to an intravenous glucose tolerance test (GTT) and examine gene expression profiles in the insulin signaling pathway (ISP) in beef animals of differing phenotypic residual feed intake (RFI). Two experiments were conducted. In Exp. 1, a total of 39 Simmental heifers, over 2 yr (yr 1, n = 22, and yr 2, n = 17; mean initial BW = 472 kg [SD = 52.4 kg]), were offered grass silage ad libitum for 104 d. Heifers were subjected to a GTT on d 8 and 65 of the RFI measurement period in yr 1 and 2, respectively. Concentrations of plasma glucose and insulin were measured at -45, -30, -15, 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 150, and 180 min relative to glucose infusion (0 min). In Exp. 2, a total of 67 Simmental bulls, over 3 yr (yr 1, n = 20; yr 2, n = 33; and yr 3, n = 14; mean initial BW = 431 kg [SD = 63.7 kg]), were offered concentrates ad libitum for 105 d. Biopsies of LM were harvested during the RFI measurement period (yr 1, d 49 and 91; yr 2, d 52 and 92; and yr 3, d 50 and 92). The residuals of the regression of DMI on ADG, midtest metabolic BW (BW(0.75)), and the fixed effect of year, using all animals, were used to compute individual RFI coefficients. Animals were ranked on RFI and assigned to high (inefficient), medium, or low groupings by dividing them into terciles, resulting in 13 heifers and 22, 23, and 22 bulls in their respective RFI groups. In Exp. 1, data from 13 heifers from each of the high- and low-RFI groups, and in Exp. 2, data from the 15 highest and 15 lowest ranking bulls on RFI are reported. In Exp. 1, glucose and insulin response and area under the response curve for glucose and insulin were similar (P > 0.05) between high- and low-RFI heifers. In Exp. 2, no differences (P > 0.05) were found for mRNA expression of 22 genes of the ISP in muscle tissue; however, expression of the transcription factor SREBP1c tended to be positively correlated (r = 0.25, P = 0.07) with RFI. Expression of GLUT4, INPPL1, and SHC increased (P < 0.05) over time, while there was no effect of sample time for any other genes measured. Collectively, these results suggest that insulin response, sensitivity, and associated expression of genes in the ISP within muscle tissue are not contributory factors to variation in RFI. However, further examination of target genes of SREBP1c, which is involved in lipogenesis, may explain some of the biochemical processes underlying variation in phenotypic RFI.
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Affiliation(s)
- C Fitzsimons
- Livestock Systems Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland UCD School of Agriculture and Food Science, Belfield, Dublin 4, Ireland
| | - D A Kenny
- Animal and Bioscience Research Department; and Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - S M Waters
- Animal and Bioscience Research Department; and Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - B Earley
- Animal and Bioscience Research Department; and Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - M McGee
- Livestock Systems Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
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Kim JN, Han SN, Kim HK. Phytic acid and myo-inositol support adipocyte differentiation and improve insulin sensitivity in 3T3-L1 cells. Nutr Res 2014; 34:723-31. [DOI: 10.1016/j.nutres.2014.07.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 07/14/2014] [Accepted: 07/23/2014] [Indexed: 11/16/2022]
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Abstract
Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological change characterized by the accumulation of triglycerides in hepatocytes and has frequently been associated with obesity, type 2 diabetes mellitus, hyperlipidemia, and insulin resistance. It is an increasingly recognized condition that has become the most common liver disorder in developed countries, affecting over one-third of the population and is associated with increased cardiovascular- and liver-related mortality. NAFLD is a spectrum of disorders, beginning as simple steatosis. In about 15% of all NAFLD cases, simple steatosis can evolve into non-alcoholic steatohepatitis, a medley of inflammation, hepatocellular injury, and fibrosis, often resulting in cirrhosis and even hepatocellular cancer. However, the molecular mechanism underlying NAFLD progression is not completely understood. Its pathogenesis has often been interpreted by the “double-hit” hypothesis. The primary insult or the “first hit” includes lipid accumulation in the liver, followed by a “second hit” in which proinflammatory mediators induce inflammation, hepatocellular injury, and fibrosis. Nowadays, a more complex model suggests that fatty acids (FAs) and their metabolites may be the true lipotoxic agents that contribute to NAFLD progression; a multiple parallel hits hypothesis has also been suggested. In NAFLD patients, insulin resistance leads to hepatic steatosis via multiple mechanisms. Despite the excess hepatic accumulation of FAs in NAFLD, it has been described that not only de novo FA synthesis is increased, but FAs are also taken up from the serum. Furthermore, a decrease in mitochondrial FA oxidation and secretion of very-low-density lipoproteins has been reported. This review discusses the molecular mechanisms that underlie the pathophysiological changes of hepatic lipid metabolism that contribute to NAFLD.
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Affiliation(s)
- Alba Berlanga
- Group GEMMAIR (AGAUR) and Applied Medicine Research Group, Department of Medicine and Surgery, Universitat Rovira i Virgili (URV), IISPV, Hospital Universitari Joan XXIII, Tarragona, Spain
| | - Esther Guiu-Jurado
- Group GEMMAIR (AGAUR) and Applied Medicine Research Group, Department of Medicine and Surgery, Universitat Rovira i Virgili (URV), IISPV, Hospital Universitari Joan XXIII, Tarragona, Spain
| | - José Antonio Porras
- Group GEMMAIR (AGAUR) and Applied Medicine Research Group, Department of Medicine and Surgery, Universitat Rovira i Virgili (URV), IISPV, Hospital Universitari Joan XXIII, Tarragona, Spain ; Department of Internal Medicine, Hospital Universitari Joan XXIII Tarragona, Tarragona, Spain
| | - Teresa Auguet
- Group GEMMAIR (AGAUR) and Applied Medicine Research Group, Department of Medicine and Surgery, Universitat Rovira i Virgili (URV), IISPV, Hospital Universitari Joan XXIII, Tarragona, Spain ; Department of Internal Medicine, Hospital Universitari Joan XXIII Tarragona, Tarragona, Spain
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Ilavenil S, Arasu MV, Lee JC, Kim DH, Vijayakumar M, Lee KD, Choi KC. Positive regulations of adipogenesis by Italian ryegrass [Lolium multiflorum] in 3T3-L1 cells. BMC Biotechnol 2014; 14:54. [PMID: 24917384 PMCID: PMC4057822 DOI: 10.1186/1472-6750-14-54] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 05/28/2014] [Indexed: 11/12/2022] Open
Abstract
BACK GROUND Intramuscular fat deposition in the meat animal is relatively new strategy for developing the meat quality. Fat deposition is largely depending on the adipocyte proliferation and differentiation. Therefore, we investigated the effect of chloroform extract of L. multiflorum [CELM] on cell proliferation, lipid accumulation and adipocyte differentiation in 3T3-L1 cells and body weight of mouse. RESULTS We identified 6,9-Octadecatrienoic acid, Hexadecanoic acid, 2-hydroxypropanoic acid, butane-2,3-diol and hexane-1,2,3,4,5,6-hexaol in CELM. L. multiflorum extract increased the cell viability, lipid accumulation, cell cycle progression and key transcriptional and secretory factors like PPRAγ2, C/CEBP-α, adiponectin, aP2, GLUT-4, FAS and SREBP-1 mRNA expression as compared with control cells. For in-vivo, mice administered with CELM significantly increased body weight throughout the experiment periods. Further, the identified fatty acids like 3, 6, 9-Octadecatrienoic acid and Hexadecanoic acid was docked with target protein [PPRAγ2] using HEX 6.12. The least binding energy considered as high affinity with target protein. The maximum affinity with the target protein was observed in the Hexadecanoic acid followed by 3, 6, 9-Octadecatrienoic acid. The binding efficacy of Hexadecanoic acid and 3, 6, 9-Octadecatrienoic acid to the active site of PPAR-γ2 may be enhanced the adipocyte differentiations. CONCLUSION These findings suggest that CELM stimulates adipogenesis via activating the PPARγ-mediated signaling pathway in adipocyte which could be useful for the development of meat quality in animals.
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Affiliation(s)
- Soundarrajan Ilavenil
- Grassland and forage division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330-801, Korea
| | - Mariadhas Valan Arasu
- Grassland and forage division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330-801, Korea
- Department of Botany and microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Jeong-Chae Lee
- Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756, Republic of Korea
| | - Da Hye Kim
- The United Graduate School of Agricultural Sciences, Tottori University, Tottori-Shi 680-8553, Japan
| | - Mayakrishnan Vijayakumar
- Grassland and forage division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330-801, Korea
| | - Kyung Dong Lee
- Department of Oriental Medicine Materials, Dongsin University, Naju 520-714, Korea
| | - Ki Choon Choi
- Grassland and forage division, National Institute of Animal Science, RDA, Seonghwan-Eup, Cheonan-Si, Chungnam 330-801, Korea
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Deficiency of the transcriptional repressor B cell lymphoma 6 (Bcl6) is accompanied by dysregulated lipid metabolism. PLoS One 2014; 9:e97090. [PMID: 24892698 PMCID: PMC4043531 DOI: 10.1371/journal.pone.0097090] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/15/2014] [Indexed: 12/28/2022] Open
Abstract
The transcriptional repressor B-cell Lymphoma 6 (Bcl6) was recently identified in a profile of genes regulated in adipocytes, suggesting a relationship between Bcl6 and metabolic regulation. As a representative target gene repressed by Bcl6, Suppressor of Cytokine Signaling (Socs) 2 expression was elevated in Bcl6 deficient (KO) mice, including metabolic tissues liver, adipose tissue and muscle, as well as in spleen and thymus. Bcl6 occupied the Socs2 promoter in wild-type, but not Bcl6 KO mice, suggesting direct regulation of Socs2 by Bcl6 in vivo. Mice deficient in Bcl6 were found to exhibit multiple features of dysregulated lipid metabolism. Adipose tissue mass was dramatically reduced or absent in Bcl6 KO mice. Further, hepatic and serum triglycerides were low. Bcl6 deficiency was accompanied by decreased hepatic expression of Stearoyl-CoA desaturase 1 (Scd1) and Fatty acid synthase (Fasn) genes which encode lipogenic enzymes. Expression of the gene for the transcription factor Carbohydrate-Responsive Element Binding Protein (Chrebp), which regulates expression of lipogenic genes, was also reduced in liver of Bcl6 KO mice. Bcl6 deficiency disrupted fasting-induced increases in hepatic triglyceride deposition, but not decreases in lipogenic gene expression. Taken together, these findings suggest that in addition to its well-recognized roles in immune regulation, Bcl6 plays a role in regulatory events of lipid metabolism, and that in the absence of Bcl6, lipid metabolism in liver and adipose tissue is dysregulated.
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Erion DM, Lapworth A, Amor PA, Bai G, Vera NB, Clark RW, Yan Q, Zhu Y, Ross TT, Purkal J, Gorgoglione M, Zhang G, Bonato V, Baker L, Barucci N, D’Aquila T, Robertson A, Aiello RJ, Yan J, Trimmer J, Rolph TP, Pfefferkorn JA. The hepatoselective glucokinase activator PF-04991532 ameliorates hyperglycemia without causing hepatic steatosis in diabetic rats. PLoS One 2014; 9:e97139. [PMID: 24858947 PMCID: PMC4032240 DOI: 10.1371/journal.pone.0097139] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 04/01/2014] [Indexed: 02/04/2023] Open
Abstract
Hyperglycemia resulting from type 2 diabetes mellitus (T2DM) is the main cause of diabetic complications such as retinopathy and neuropathy. A reduction in hyperglycemia has been shown to prevent these associated complications supporting the importance of glucose control. Glucokinase converts glucose to glucose-6-phosphate and determines glucose flux into the β-cells and hepatocytes. Since activation of glucokinase in β-cells is associated with increased risk of hypoglycemia, we hypothesized that selectively activating hepatic glucokinase would reduce fasting and postprandial glucose with minimal risk of hypoglycemia. Previous studies have shown that hepatic glucokinase overexpression is able to restore glucose homeostasis in diabetic models; however, these overexpression experiments have also revealed that excessive increases in hepatic glucokinase activity may also cause hepatosteatosis. Herein we sought to evaluate whether liver specific pharmacological activation of hepatic glucokinase is an effective strategy to reduce hyperglycemia without causing adverse hepatic lipids changes. To test this hypothesis, we evaluated a hepatoselective glucokinase activator, PF-04991532, in Goto-Kakizaki rats. In these studies, PF-04991532 reduced plasma glucose concentrations independent of changes in insulin concentrations in a dose-dependent manner both acutely and after 28 days of sub-chronic treatment. During a hyperglycemic clamp in Goto-Kakizaki rats, the glucose infusion rate was increased approximately 5-fold with PF-04991532. This increase in glucose infusion can be partially attributed to the 60% reduction in endogenous glucose production. While PF-04991532 induced dose-dependent increases in plasma triglyceride concentrations it had no effect on hepatic triglyceride concentrations in Goto-Kakizaki rats. Interestingly, PF-04991532 decreased intracellular AMP concentrations and increased hepatic futile cycling. These data suggest that hepatoselective glucokinase activation may offer glycemic control without inducing hepatic steatosis supporting the evaluation of tissue specific activators in clinical trials.
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Affiliation(s)
- Derek M. Erion
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
- * E-mail:
| | - Amanda Lapworth
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Paul A. Amor
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Guoyun Bai
- Groton Center of Chemistry, Pfizer Worldwide Research & Development, Groton, Connecticut, United States of America
| | - Nicholas B. Vera
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Ronald W. Clark
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Qingyun Yan
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Yimin Zhu
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Trenton T. Ross
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Julie Purkal
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Matthew Gorgoglione
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Guodong Zhang
- Groton Center of Chemistry, Pfizer Worldwide Research & Development, Groton, Connecticut, United States of America
| | - Vinicius Bonato
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Levenia Baker
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Nicole Barucci
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Theresa D’Aquila
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Alan Robertson
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Robert J. Aiello
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Jiangli Yan
- Groton Center of Chemistry, Pfizer Worldwide Research & Development, Groton, Connecticut, United States of America
| | - Jeff Trimmer
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Timothy P. Rolph
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
| | - Jeffrey A. Pfefferkorn
- Cardiovascular, Metabolic & Endocrine Disease Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, United States of America
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Dong Q, Giorgianni F, Deng X, Beranova-Giorgianni S, Bridges D, Park EA, Raghow R, Elam MB. Phosphorylation of sterol regulatory element binding protein-1a by protein kinase A (PKA) regulates transcriptional activity. Biochem Biophys Res Commun 2014; 449:449-54. [PMID: 24853806 DOI: 10.1016/j.bbrc.2014.05.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 05/08/2014] [Indexed: 10/25/2022]
Abstract
The counter-regulatory hormone glucagon inhibits lipogenesis via downregulation of sterol regulatory element binding protein 1 (SREBP-1). The effect of glucagon is mediated via protein kinase A (PKA). To determine if SREBP-1 is a direct phosphorylation target of PKA, we conducted mass spectrometry analysis of recombinant n-terminal SREBP-1a following PKA treatment in vitro. This analysis identified serines 331/332 as bona-fide phosphorylation targets of PKA. To determine the functional consequences of phosphorylation at these sites, we constructed mammalian expression vector for both nSREBP-1a and 1c isoforms in which the candidate PKA phosphorylation sites were mutated to active phosphomimetic or non-phosphorylatable amino acids. The transcriptional activity of SREBP was reduced by the phosphomimetic mutation of S332 of nSREBP-1a and the corresponding serine (S308) of nSREBP-1c. This site is a strong candidate for mediating the negative regulatory effect of glucagon on SREBP-1 and lipogenesis.
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Affiliation(s)
- Qingming Dong
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Francesco Giorgianni
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Xiong Deng
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN, USA; Research Service, Veteran's Affairs Medical Center, Memphis, TN, USA
| | - Sarka Beranova-Giorgianni
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Dave Bridges
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Edwards A Park
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Rajendra Raghow
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN, USA; Research Service, Veteran's Affairs Medical Center, Memphis, TN, USA
| | - Marshall B Elam
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN, USA; Research Service, Veteran's Affairs Medical Center, Memphis, TN, USA.
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Grube S, Dünisch P, Freitag D, Klausnitzer M, Sakr Y, Walter J, Kalff R, Ewald C. Overexpression of fatty acid synthase in human gliomas correlates with the WHO tumor grade and inhibition with Orlistat reduces cell viability and triggers apoptosis. J Neurooncol 2014; 118:277-287. [PMID: 24789255 DOI: 10.1007/s11060-014-1452-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 04/20/2014] [Indexed: 02/08/2023]
Abstract
Fatty acid synthase (FASN), catalyzing the de novo synthesis of fatty acids, is known to be deregulated in several cancers. Inhibition of this enzyme reduces tumor cell proliferation. Unfortunately, adverse effects and chemical instability prevent the in vivo use of the best-known inhibitors, Cerulenin and C75. Orlistat, a drug used for obesity treatment, is also considered as a potential FASN inhibitor, but its impact on glioma cell biology has not yet been described. In this study, we analyzed FASN expression in human glioma samples and primary glioblastoma cell cultures and the effects of FASN inhibition with Orlistat, Cerulenin and C75. Immunohistochemistry followed by densitometric analysis of 20 glioma samples revealed overexpression of FASN that correlated with the WHO tumor grade. Treatment of glioblastoma cells with these inhibitors resulted in a significant, dose-dependent reduction in tumor cell viability and fatty acid synthesis. Compared to Cerulenin and C75, Orlistat was a more potent inhibitor in cell cultures and cell lines. In LN229, cell-growth was reduced by 63.9 ± 8.7 % after 48 h and 200 µM Orlistat compared to controls; in LT68, the reduction in cell growth was 76.3 ± 23.7 %. Nuclear fragmentation assay and Western blotting analysis after targeting FASN with Orlistat demonstrated autophagy and apoptosis. Organotypic slice cultures treated with Orlistat showed reduced proliferation after Ki67 staining and increased caspase-3 cleavage. Our results suggest that FASN may be a therapeutic target in malignant gliomas and identify Orlistat as a possible anti-tumor drug in this setting.
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Affiliation(s)
- Susanne Grube
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany.
| | - Pedro Dünisch
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Diana Freitag
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Maren Klausnitzer
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Yasser Sakr
- Department of Anesthesiology and Intensive Care, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Jan Walter
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Rolf Kalff
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Christian Ewald
- Department of Neurosurgery, Section of Experimental Neurooncology, Jena University Hospital, Friedrich-Schiller-University Jena, Erlanger Allee 101, 07747, Jena, Germany
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127
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Suppression of adipogenesis by valproic acid through repression of USF1-activated fatty acid synthesis in adipocytes. Biochem J 2014; 459:489-503. [DOI: 10.1042/bj20131476] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Valproic acid suppresses the accumulation of the intracellular lipids through suppression of fatty acid synthesis via repression of USF1-mediated expression of the fatty acid synthase gene in adipocytes.
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128
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Kersten S. Physiological regulation of lipoprotein lipase. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:919-33. [PMID: 24721265 DOI: 10.1016/j.bbalip.2014.03.013] [Citation(s) in RCA: 341] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 01/01/2023]
Abstract
The enzyme lipoprotein lipase (LPL), originally identified as the clearing factor lipase, hydrolyzes triglycerides present in the triglyceride-rich lipoproteins VLDL and chylomicrons. LPL is primarily expressed in tissues that oxidize or store fatty acids in large quantities such as the heart, skeletal muscle, brown adipose tissue and white adipose tissue. Upon production by the underlying parenchymal cells, LPL is transported and attached to the capillary endothelium by the protein GPIHBP1. Because LPL is rate limiting for plasma triglyceride clearance and tissue uptake of fatty acids, the activity of LPL is carefully controlled to adjust fatty acid uptake to the requirements of the underlying tissue via multiple mechanisms at the transcriptional and post-translational level. Although various stimuli influence LPL gene transcription, it is now evident that most of the physiological variation in LPL activity, such as during fasting and exercise, appears to be driven via post-translational mechanisms by extracellular proteins. These proteins can be divided into two main groups: the liver-derived apolipoproteins APOC1, APOC2, APOC3, APOA5, and APOE, and the angiopoietin-like proteins ANGPTL3, ANGPTL4 and ANGPTL8, which have a broader expression profile. This review will summarize the available literature on the regulation of LPL activity in various tissues, with an emphasis on the response to diverse physiological stimuli.
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Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD Wageningen, The Netherlands
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129
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Kalantarian S, Rimm EB, Herrington DM, Mozaffarian D. Dietary macronutrients, genetic variation, and progression of coronary atherosclerosis among women. Am Heart J 2014; 167:627-635.e1. [PMID: 24655714 DOI: 10.1016/j.ahj.2014.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 01/06/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Previous studies observed the surprising finding that saturated fat was inversely associated with atherosclerosis progression in postmenopausal women, whereas polyunsaturated fat (PUFA) and carbohydrates were positively associated. Whether certain genes modify the association of diet with atherosclerotic progression is unknown. METHODS Using Haplotype-tagging single nucleotide polymorphisms, we evaluated gene-diet interactions with 3 preselected genes involved in fatty acid and carbohydrate metabolism: sterol regulatory element binding protein-1 (SREBP1), insulin-induced gene-1 (INSIG1), and SREBP cleavage-activating protein (SCAP). Diet was assessed at baseline. Quantitative coronary angiography was performed at baseline and after a mean of follow-up of 3.09 years in 2,227 coronary segments in 234 postmenopausal women. RESULTS Global effects of each gene and gene-diet interactions for different fats, total fat, and carbohydrate were evaluated. Global tests revealed no main effects between SCAP, INSIG1, and SREBP1 haplotypes and progression of atherosclerosis (P = .87, P = .58, and P = .44). After correction for 5 nutrients evaluated (Bonferroni-corrected 2-tailed α = .01), no significant gene-nutrient interactions were seen, except for a borderline global interaction between SREBP1 and PUFA intake (P interaction = .013). This interaction was specific to the G-C haplotype (frequency 35%) and was driven by n-6 rather than n-3 PUFA (P for interaction < .0001). The interaction was robust to estimated isocaloric replacement of PUFA with any other nutrient. Per each 5% energy from n-6 PUFA, a 0.21-mm greater decline in mean minimal coronary artery diameter was seen among women per each copy of the second most frequent haplotype of SREBP1. CONCLUSIONS We observed an interaction between SREBP1 and PUFA consumption that might explain the positive association of PUFA with atherosclerosis progression in this cohort.
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130
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Mennigen JA, Plagnes-Juan E, Figueredo-Silva CA, Seiliez I, Panserat S, Skiba-Cassy S. Acute endocrine and nutritional co-regulation of the hepatic omy-miRNA-122b and the lipogenic gene fas in rainbow trout, Oncorhynchus mykiss. Comp Biochem Physiol B Biochem Mol Biol 2014; 169:16-24. [DOI: 10.1016/j.cbpb.2013.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/23/2013] [Accepted: 12/04/2013] [Indexed: 12/25/2022]
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Kwon SM, Park HG, Jun JK, Lee WL. Exercise, but not quercetin, ameliorates inflammation, mitochondrial biogenesis, and lipid metabolism in skeletal muscle after strenuous exercise by high-fat diet mice. J Exerc Nutrition Biochem 2014; 18:51-60. [PMID: 25566439 PMCID: PMC4241935 DOI: 10.5717/jenb.2014.18.1.51] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 02/14/2014] [Accepted: 02/26/2014] [Indexed: 01/08/2023] Open
Abstract
[Purpose] The purpose of this study was to investigate whether moderate exercise and quercetin intake with a low fat diet contribute to inflammatory cytokine production, mitochondrial biogenesis, and lipid metabolism in skeletal muscle after strenuous exercise by high-fat diet mice. [Methods] Male C57BL/6 mice were randomly divided into four groups: (1) High-fat for 12 weeks and low-fat diet control (C; n = 6); (2) high-fat diet for 12 weeks and low-fat diet with quercetin (Q; n = 4); (3) high-fat diet for 12 weeks and low-fat diet with exercise (E; n = 4); or (4) high-fat diet for 12 weeks and low-fat diet with exercise and quercetin (EQ; n = 5). Quercetin (10 mg/kg) was administered once per day, 5 day/week for 8 weeks. Exercise training was performed at moderate intensity for 8 weeks, 5 days/week for 30–60 min/day. Mice were subjected to a strenuous exercise bout of 60 min at a speed of 25 m/min (VO2 max 85%) conducted as an exercise-induced fatigue just before sacrifice. [Results] As results, body weights were significantly different among the groups. Exercise training significantly reduced inflammatory cytokines after strenuous exercise in skeletal muscle of high-fat diet mice. Exercise training increased Tfam mRNA in the soleus muscle after strenuous exercise. Exercise training significantly decreased lipogenesis markers in skeletal muscle of obese mice after strenuous exercise. Moderate exercise significantly increased lipolysis markers in the tibialis anterior muscle. [Conclusion] These findings suggest that exercise training reduced inflammatory cytokine levels and improved mitochondrial biogenesis and lipid metabolism. However quercetin supplementation did not affect these parameters. Thus, long-term moderate exercise training has positive effects on obesity.
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Affiliation(s)
- Soon Mi Kwon
- Department of Sports Science, Chungnam National University, Daejeon, Korea
| | - Hee Geun Park
- Department of Sports Science, Chungnam National University, Daejeon, Korea
| | - Jong Kui Jun
- Department of Sports Science, Chungnam National University, Daejeon, Korea
| | - Wang Lok Lee
- Department of Sports Science, Chungnam National University, Daejeon, Korea
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132
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Eisenstein A, Ravid K. G protein-coupled receptors and adipogenesis: a focus on adenosine receptors. J Cell Physiol 2014; 229:414-21. [PMID: 24114647 DOI: 10.1002/jcp.24473] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/12/2013] [Indexed: 12/20/2022]
Abstract
G-protein coupled receptors (GPCRs) are a large family of proteins that coordinate extracellular signals to produce physiologic outcomes. Adenosine receptors (AR) are one class of GPCRs that have been shown to regulate functions as diverse as inflammation, blood flow, and cellular differentiation. Adenosine signals through four GPCRs that either inhibit (A1AR and A3AR) or activate (A2aAR and A2bAR) adenylyl cyclase. This review will focus on the role of GPCRs, and in particular, adenosine receptors, in adipogenesis. Preadipocytes differentiate to mature adipocytes as the adipose tissue expands to compensate for the consumption of excess nutrients. These newly generated adipocytes contribute to maintaining metabolic homeostasis. Understanding the key drivers of this differentiation process can aid the development of therapeutics to combat the growing obesity epidemic and associated metabolic consequences. Although much literature has covered the transcriptional events that culminate in the formation of an adipocyte, less focus has been on receptor-mediated extracellular signals that direct this process. This review will highlight GPCRs and their downstream messengers as significant players controlling adipocyte differentiation.
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Affiliation(s)
- Anna Eisenstein
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts; Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
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133
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Cilostazol inhibits insulin-stimulated expression of sterol regulatory binding protein-1c via inhibition of LXR and Sp1. Exp Mol Med 2014; 46:e73. [PMID: 24458133 PMCID: PMC3909891 DOI: 10.1038/emm.2013.143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 10/10/2013] [Accepted: 10/21/2013] [Indexed: 12/20/2022] Open
Abstract
Hepatic steatosis is common in obese individuals with hyperinsulinemia and is an important hepatic manifestation of metabolic syndrome. Sterol regulatory binding protein-1c (SREBP-1c) is a master regulator of lipogenic gene expression in the liver. Hyperinsulinemia induces transcription of SREBP-1c via activation of liver X receptor (LXR) and specificity protein 1 (Sp1). Cilostazol is an antiplatelet agent that prevents atherosclerosis and decreases serum triglyceride levels. However, little is known about the effects of cilostazol on hepatic lipogenesis. Here, we examined the role of cilostazol in the regulation of SREBP-1c transcription in the liver. The effects of cilostazol on the expression of SREBP-1c and its target genes in response to insulin or an LXR agonist (T0901317) were examined using real-time RT-PCR and western blot analysis on cultured hepatocytes. To investigate the effect of cilostazol on SREBP-1c at the transcriptional level, transient transfection reporter assays and electrophoretic mobility shift assays (EMSAs) were performed. Cilostazol inhibited insulin-induced and LXR-agonist-induced expression of SREBP-1c and its downstream targets, acetyl-CoA carboxylase and fatty acid synthase, in cultured hepatocytes. Cilostazol also inhibited activation of the SREBP-1c promoter by insulin, T0901317 and Sp1 in a luciferase reporter assay. EMSA analysis showed that cilostazol inhibits SREBP-1c expression by repressing the binding of LXR and Sp1 to the promoter region. These results indicate that cilostazol inhibits insulin-induced hepatic SREBP-1c expression via the inhibition of LXR and Sp1 activity and that cilostazol is a negative regulator of hepatic lipogenesis.
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134
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Zhang HB, Wang ZS, Peng QH, Tan C, Zou HW. Effects of different levels of protein supplementary diet on gene expressions related to intramuscular deposition in early-weaned yaks. Anim Sci J 2014; 85:411-9. [PMID: 24450936 DOI: 10.1111/asj.12161] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 10/02/2013] [Indexed: 11/28/2022]
Abstract
This study was conducted to estimate different levels of protein supplementary diet on gene expressions related to intramuscular deposition in early-weaned yaks. Results showed that supplementary dietary protein significantly increased final weight, average daily gain (ADG), intramuscular fat (IMF), serum free fatty acid (FFA), total triglycerides, total cholesterol (Ch), low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL) content. There was a quadratic response of ADG, IMF, FFA, Ch, HDL and LDL to dietary crude protein (CP) level. Lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) enzyme activities were significantly increased by supplementary dietary CP, while hormone-sensitive lipase (HSL) and carnitine palmitoyltransferase-1 (CPT-1) activities were significantly decreased. LPL, ACC and FAS enzyme activities showed quadratic increase as dietary CP increased. Peroxisome proliferator-activated receptor γ (PPARγ), LPL, FAS, sterol regulatory element binding protein 1 (SREBP-1), ACC, stearoyl-CoA desaturase (SCD) and heart fatty-acid binding protein (H-FABP) gene expression were significantly increased by supplementary dietary CP, while HSL and CPT-1 gene expression were significantly decreased. PPARγ, LPL, SREBP-1, ACC and H-FABP gene expression showed quadratic increase as dietary CP increased. These results indicated that supplementary dietary protein increased IMF accumulation mainly to increased intramuscular lipogenic gene expression and decreased lipolytic gene expression.
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Affiliation(s)
- Hai-Bo Zhang
- Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Animal Nutrition Institute of Sichuan Agricultural University, Ya'an, China
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135
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Tanaka Y, Nagao K, Nakagiri H, Nagaso T, Iwasa Y, Mori H, Asahina M, Imaizumi K, Sato M. Unavailability of liver triacylglycerol increases serum cholesterol concentration induced by dietary cholesterol in exogenously hypercholesterolemic (ExHC) rats. Lipids Health Dis 2014; 13:19. [PMID: 24450544 PMCID: PMC3902423 DOI: 10.1186/1476-511x-13-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 01/14/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Exogenously hypercholesterolemic (ExHC) rats develop hypercholesterolemia and low hepatic triacylglycerol (TAG) levels when dietary cholesterol is loaded. The responsible gene Smek2 was identified via linkage analysis using the original strain Sprague-Dawley (SD) rats. In this study, we compared SD and ExHC rats to investigate a relationship between hypercholesterolemia and the low hepatic TAG levels observed in ExHC rats. METHODS Male 4-weeks-old ExHC and SD rats were fed a 1% cholesterol diet for 1 week. Serum and liver parameters were analyzed. Gene expression and enzyme activities related to TAG metabolism were also assessed. RESULTS We reproducibly observed higher serum cholesterol and lower hepatic TAG levels in ExHC rats than in SD rats. Golgi apparatus in the livers of ExHC rats secreted β-very-low-density lipoprotein (β-VLDL) that had higher cholesterol ester (CE) and lower TAG content than those in the β-VLDL secreted by SD rats. Gene expression related to fatty acid and TAG synthesis in ExHC rats was lower than that in SD rats. Enzymatic activities for fatty acid synthesis were also relatively lower in ExHC rats. Moreover, the fatty acid composition of hepatic and serum CE in ExHC rats showed that these CEs were not modified after secretion from the liver despite the similar activities of serum lecithin-cholesterol acyltransferase (LCAT) in ExHC rats to those in SD rats. CONCLUSIONS Low production of liver TAG and secretion of CE-rich, TAG-poor β-VLDL without modification by LCAT in the circulation contributed to hypercholesterolemia induced by dietary cholesterol in ExHC rats.
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Affiliation(s)
- Yasutake Tanaka
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Koji Nagao
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Hideaki Nakagiri
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Toshirou Nagaso
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Yasue Iwasa
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Haruhiko Mori
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Makoto Asahina
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Katsumi Imaizumi
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
| | - Masao Sato
- Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, 6-10-1 hakozaki, higashi-ku, Fukuoka 812-8581, Japan
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136
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In vitro and in vivo enhancement of adipogenesis by Italian ryegrass (Lolium multiflorum) in 3T3-L1 cells and mice. PLoS One 2014; 9:e85297. [PMID: 24454838 PMCID: PMC3890303 DOI: 10.1371/journal.pone.0085297] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 11/25/2013] [Indexed: 12/21/2022] Open
Abstract
Adipogenesis is very much important in improving the quality of meat in animals. The aim of the present study was to investigate the in vitro and in vivo adipogenesis regulation properties of Lolium multiflorum on 3T3-L1 pre-adipocytes and mice. Chemical composition of petroleum ether extract of L. multiflorum (PET-LM) confirmed the presence of fatty acids, such as α-linolenic acid, docosahexaenoic acid, oleic acid, docosatetraenoic acid, and caprylic acid, as the major compounds. PET-LM treatment increased viability, lipid accumulation, lipolysis, cell cycle progression, and DNA synthesis in the cells. PET-LM treatment also augmented peroxysome proliferator activated receptor (PPAR)-γ2, CCAAT/enhancer binding protein-α, adiponectin, adipocyte binding protein, glucose transporter-4, fatty acid synthase, and sterol regulatory element binding protein-1 expression at mRNA and protein levels in differentiated adipocytes. In addition, mice administered with 200 mg/kg body weight PET-LM for 8 weeks showed greater body weight than control mice. These findings suggest that PET-LM facilitates adipogenesis by stimulating PPARγ-mediated signaling cascades in adipocytes which could be useful for quality meat development in animals.
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137
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Taniguchi M, Nakajima I, Chikuni K, Kojima M, Awata T, Mikawa S. MicroRNA-33b downregulates the differentiation and development of porcine preadipocytes. Mol Biol Rep 2014; 41:1081-90. [PMID: 24398549 PMCID: PMC3929038 DOI: 10.1007/s11033-013-2954-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 12/20/2013] [Indexed: 12/26/2022]
Abstract
Sterol regulatory element binding transcription factor (SREBF) is a key transcription regulator for lipid homeostasis. MicroRNA-33b (miR-33b) is embedded in intron 16 of porcine SREBF1 and is conserved among most mammals. Here, we investigated the effect of miR-33b on adipocyte differentiation and development in porcine subcutaneous pre-adipocytes (PSPA). PSPA were transiently transfected with miR-33b, and adipose differentiation was then induced. Delayed adipose differentiation and decreased lipid accumulation were observed in miR-33b-transfected PSPA. Computational predictions suggested that miR-33b may target early B cell factor 1 (EBF1), an adipocyte activator of lipogenesis regulators such as CCAAT-enhancer binding protein alpha (C/EBPα) and peroxisome proliferator-activated receptor gamma (PPARγ). Both gene and protein expression of EBF1 were downregulated in miR-33b-transfected PSPA, followed by considerable decreases in the expression of C/EBPα and PPARγ and their downstream lipogenic genes. However, miR-33b transfection did not markedly affect mRNA and protein expression of SREBF1. We also investigated differences in the expression of miR-33b and lipogenic genes in subcutaneous fat tissues between 5-month-old crossbred gilts derived from Landrace (lean-type) and Meishan (fatty-type) boars. Landrace-derived crossbred gilts expressed more miR-33b and less lipogenic genes than did gilts derived from Meishan. Our results suggest that miR-33b affected the differentiation and development of PSPA by attenuating the lipogenic gene expression cascade through EBF1 to C/EBPα and PPARγ. The differential expression of miR-33b observed in crossbred gilts may in part account for differences in lipogenic gene expression and the fat:lean ratio between pig breeds.
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Affiliation(s)
- Masaaki Taniguchi
- Animal Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
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MORISHITA S, MOCHIZUKI K, GODA T. Bindings of ChREBP and SREBP1, and Histone Acetylation around the Rat Liver Fatty Acid Synthase Gene Are Associated with Induction of the Gene during the Suckling-Weaning Transition. J Nutr Sci Vitaminol (Tokyo) 2014; 60:94-100. [DOI: 10.3177/jnsv.60.94] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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139
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Janssens J, Etienne H, Idriss S, Azmi A, Martin B, Maudsley S. Systems-Level G Protein-Coupled Receptor Therapy Across a Neurodegenerative Continuum by the GLP-1 Receptor System. Front Endocrinol (Lausanne) 2014; 5:142. [PMID: 25225492 PMCID: PMC4150252 DOI: 10.3389/fendo.2014.00142] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/14/2014] [Indexed: 12/31/2022] Open
Abstract
With our increasing appreciation of the true complexity of diseases and pathophysiologies, it is clear that this knowledge needs to inform the future development of pharmacotherapeutics. For many disorders, the disease mechanism itself is a complex process spanning multiple signaling networks, tissues, and organ systems. Identifying the precise nature and locations of the pathophysiology is crucial for the creation of systemically effective drugs. Diseases once considered constrained to a limited range of organ systems, e.g., central neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington' disease (HD), the role of multiple central and peripheral organ systems in the etiology of such diseases is now widely accepted. With this knowledge, it is increasingly clear that these seemingly distinct neurodegenerative disorders (AD, PD, and HD) possess multiple pathophysiological similarities thereby demonstrating an inter-related continuum of disease-related molecular alterations. With this systems-level appreciation of neurodegenerative diseases, it is now imperative to consider that pharmacotherapeutics should be developed specifically to address the systemic imbalances that create the disorders. Identification of potential systems-level signaling axes may facilitate the generation of therapeutic agents with synergistic remedial activity across multiple tissues, organ systems, and even diseases. Here, we discuss the potentially therapeutic systems-level interaction of the glucagon-like peptide 1 (GLP-1) ligand-receptor axis with multiple aspects of the AD, PD, and HD neurodegenerative continuum.
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Affiliation(s)
- Jonathan Janssens
- Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
| | - Harmonie Etienne
- Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
| | - Sherif Idriss
- Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
| | - Abdelkrim Azmi
- Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
| | - Bronwen Martin
- Metabolism Unit, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Stuart Maudsley
- Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
- *Correspondence: Stuart Maudsley, Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, Universiteitsplein 1, Building V, Antwerpen B2610, Belgium e-mail:
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PIASy-mediated sumoylation of SREBP1c regulates hepatic lipid metabolism upon fasting signaling. Mol Cell Biol 2013; 34:926-38. [PMID: 24379443 DOI: 10.1128/mcb.01166-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SREBP1c is a key transcription factor that regulates de novo lipogenesis during anabolic periods. However, the molecular mechanisms involved in the suppression of SREBP1c under nutritional deprivation are largely unknown. In this study, we demonstrate that the small ubiquitin-related modifier (SUMO) E3 ligase, a protein inhibitor of activated STAT Y (PIASy), sumoylates SREBP1c at Lys98, leading to suppression of the hepatic lipogenic program upon fasting-induced signals. In primary hepatocytes, ablation of PIASy stimulated intracellular lipid accumulation through the induction of SREBP1c and its target genes. Given that protein kinase A (PKA) plays important roles in catabolic responses, activated PKA enhances the sumoylation of SREBP1c and potentiates the interaction between SREBP1c and PIASy. Notably, overexpression of PIASy in obese db/db mice ameliorated hepatic steatosis, while suppression of PIASy in lean (wild-type) mice stimulated hepatic lipogenesis with increased expression of SREBP1c target genes. Furthermore, PKA-mediated SREBP1c phosphorylation augmented SREBP1c sumoylation, subsequently leading to degradation of SREBP1c via ubiquitination. Together, these data suggest that PKA-induced SREBP1c sumoylation by PIASy is a key regulatory mechanism to turn off hepatic lipogenesis during nutritional deprivation.
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141
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Fetal and neonatal exposure to nicotine leads to augmented hepatic and circulating triglycerides in adult male offspring due to increased expression of fatty acid synthase. Toxicol Appl Pharmacol 2013; 275:1-11. [PMID: 24368177 DOI: 10.1016/j.taap.2013.12.010] [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: 10/02/2013] [Revised: 12/09/2013] [Accepted: 12/12/2013] [Indexed: 12/25/2022]
Abstract
While nicotine replacement therapy is assumed to be a safer alternative to smoking during pregnancy, the long-term consequences for the offspring remain elusive. Animal studies now suggest that maternal nicotine exposure during perinatal life leads to a wide range of adverse outcomes for the offspring including increased adiposity. The focus of this study was to investigate if nicotine exposure during pregnancy and lactation leads to alterations in hepatic triglyceride synthesis. Female Wistar rats were randomly assigned to receive daily subcutaneous injections of saline (vehicle) or nicotine bitartrate (1mg/kg/day) for two weeks prior to mating until weaning. At postnatal day 180 (PND 180), nicotine exposed offspring exhibited significantly elevated levels of circulating and hepatic triglycerides in the male offspring. This was concomitant with increased expression of fatty acid synthase (FAS), the critical hepatic enzyme in de novo triglyceride synthesis. Given that FAS is regulated by the nuclear receptor Liver X receptor (LXRα), we measured LXRα expression in both control and nicotine-exposed offspring. Nicotine exposure during pregnancy and lactation led to an increase in hepatic LXRα protein expression and enriched binding to the putative LXRE element on the FAS promoter in PND 180 male offspring. This was also associated with significantly enhanced acetylation of histone H3 [K9,14] surrounding the FAS promoter, a hallmark of chromatin activation. Collectively, these findings suggest that nicotine exposure during pregnancy and lactation leads to an increase in circulating and hepatic triglycerides long-term via changes in the transcriptional and epigenetic regulation of the hepatic lipogenic pathway.
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142
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Nakamura MT, Yudell BE, Loor JJ. Regulation of energy metabolism by long-chain fatty acids. Prog Lipid Res 2013; 53:124-44. [PMID: 24362249 DOI: 10.1016/j.plipres.2013.12.001] [Citation(s) in RCA: 482] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 12/12/2022]
Abstract
In mammals, excess energy is stored primarily as triglycerides, which are mobilized when energy demands arise. This review mainly focuses on the role of long chain fatty acids (LCFAs) in regulating energy metabolism as ligands of peroxisome proliferator-activated receptors (PPARs). PPAR-alpha expressed primarily in liver is essential for metabolic adaptation to starvation by inducing genes for beta-oxidation and ketogenesis and by downregulating energy expenditure through fibroblast growth factor 21. PPAR-delta is highly expressed in skeletal muscle and induces genes for LCFA oxidation during fasting and endurance exercise. PPAR-delta also regulates glucose metabolism and mitochondrial biogenesis by inducing FOXO1 and PGC1-alpha. Genes targeted by PPAR-gamma in adipocytes suggest that PPAR-gamma senses incoming non-esterified LCFAs and induces the pathways to store LCFAs as triglycerides. Adiponectin, another important target of PPAR-gamma may act as a spacer between adipocytes to maintain their metabolic activity and insulin sensitivity. Another topic of this review is effects of skin LCFAs on energy metabolism. Specific LCFAs are required for the synthesis of skin lipids, which are essential for water barrier and thermal insulation functions of the skin. Disturbance of skin lipid metabolism often causes apparent resistance to developing obesity at the expense of normal skin function.
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Affiliation(s)
- Manabu T Nakamura
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 905 South Goodwin Avenue, Urbana, IL 61801, USA.
| | - Barbara E Yudell
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 905 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Juan J Loor
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 905 South Goodwin Avenue, Urbana, IL 61801, USA
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143
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Yang M, Liu W, Pellicane C, Sahyoun C, Joseph BK, Gallo-Ebert C, Donigan M, Pandya D, Giordano C, Bata A, Nickels JT. Identification of miR-185 as a regulator of de novo cholesterol biosynthesis and low density lipoprotein uptake. J Lipid Res 2013; 55:226-38. [PMID: 24296663 DOI: 10.1194/jlr.m041335] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Dysregulation of cholesterol homeostasis is associated with various metabolic diseases, including atherosclerosis and type 2 diabetes. The sterol response element binding protein (SREBP)-2 transcription factor induces the expression of genes involved in de novo cholesterol biosynthesis and low density lipoprotein (LDL) uptake, thus it plays a crucial role in maintaining cholesterol homeostasis. Here, we found that overexpressing microRNA (miR)-185 in HepG2 cells repressed SREBP-2 expression and protein level. miR-185-directed inhibition caused decreased SREBP-2-dependent gene expression, LDL uptake, and HMG-CoA reductase activity. In addition, we found that miR-185 expression was tightly regulated by SREBP-1c, through its binding to a single sterol response element in the miR-185 promoter. Moreover, we found that miR-185 expression levels were elevated in mice fed a high-fat diet, and this increase correlated with an increase in total cholesterol level and a decrease in SREBP-2 expression and protein. Finally, we found that individuals with high cholesterol had a 5-fold increase in serum miR-185 expression compared with control individuals. Thus, miR-185 controls cholesterol homeostasis through regulating SREBP-2 expression and activity. In turn, SREBP-1c regulates miR-185 expression through a complex cholesterol-responsive feedback loop. Thus, a novel axis regulating cholesterol homeostasis exists that exploits miR-185-dependent regulation of SREBP-2 and requires SREBP-1c for function.
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Affiliation(s)
- Muhua Yang
- The Institute of Metabolic Disorders and Genesis Biotechnology Group, Hamilton, NJ 08691
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144
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Abstract
The liver plays a unique, central role in regulating lipid metabolism. In addition to influencing hepatic function and disease, changes in specific pathways of fatty acid (FA) metabolism have wide-ranging effects on the metabolism of other nutrients, extra-hepatic physiology, and the development of metabolic diseases. The high prevalence of nonalcoholic fatty liver disease (NAFLD) has led to increased efforts to characterize the underlying biology of hepatic energy metabolism and FA trafficking that leads to disease development. Recent advances have uncovered novel roles of metabolic pathways and specific enzymes in generating lipids important for cellular processes such as signal transduction and transcriptional activation. These studies have also advanced our understanding of key branch points involving FA partitioning between metabolic pathways and have identified new roles for lipid droplets in these events. This review covers recent advances in our understanding of FA trafficking and its regulation. An emphasis will be placed on branch points in these pathways and how alterations in FA trafficking contribute to NAFLD and related comorbidities.
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145
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Schupp M, Chen F, Briggs ER, Rao S, Pelzmann HJ, Pessentheiner AR, Bogner-Strauss JG, Lazar MA, Baldwin D, Prokesch A. Metabolite and transcriptome analysis during fasting suggest a role for the p53-Ddit4 axis in major metabolic tissues. BMC Genomics 2013; 14:758. [PMID: 24191950 PMCID: PMC3907060 DOI: 10.1186/1471-2164-14-758] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 10/31/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Fasting induces specific molecular and metabolic adaptions in most organisms. In biomedical research fasting is used in metabolic studies to synchronize nutritional states of study subjects. Because there is a lack of standardization for this procedure, we need a deeper understanding of the dynamics and the molecular mechanisms in fasting. RESULTS We investigated the dynamic changes of liver gene expression and serum parameters of mice at several time points during a 48 hour fasting experiment and then focused on the global gene expression changes in epididymal white adipose tissue (WAT) as well as on pathways common to WAT, liver, and skeletal muscle. This approach produced several intriguing insights: (i) rather than a sequential activation of biochemical pathways in fasted liver, as current knowledge dictates, our data indicates a concerted parallel response; (ii) this first characterization of the transcriptome signature of WAT of fasted mice reveals a remarkable activation of components of the transcription apparatus; (iii) most importantly, our bioinformatic analyses indicate p53 as central node in the regulation of fasting in major metabolic tissues; and (iv) forced expression of Ddit4, a fasting-regulated p53 target gene, is sufficient to augment lipolysis in cultured adipocytes. CONCLUSIONS In summary, this combination of focused and global profiling approaches provides a comprehensive molecular characterization of the processes operating during fasting in mice and suggests a role for p53, and its downstream target Ddit4, as novel components in the transcriptional response to food deprivation.
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Affiliation(s)
- Michael Schupp
- Department of Endocrinology, Diabetes, and Nutrition and Center for Cardiovascular Research (CCR), Charité University Medicine, Hessische Str. 3-4, Berlin 10115, Germany
| | - Fang Chen
- Department of Microbiology, 201 Johnson Pavilion, Perelman School of Medicine University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA 19104, USA
| | - Erika R Briggs
- Department of Medicine, and the Institute for Diabetes, Obesity, and Metabolism, Division of Endocrinology, Diabetes, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shilpa Rao
- Penn Bioinformatics Core, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Helmut J Pelzmann
- Institute for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, Graz 8010, Austria
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, Graz 8010, Austria
| | - Ariane R Pessentheiner
- Institute for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, Graz 8010, Austria
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, Graz 8010, Austria
| | - Juliane G Bogner-Strauss
- Institute for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, Graz 8010, Austria
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, Graz 8010, Austria
| | - Mitchell A Lazar
- Department of Medicine, and the Institute for Diabetes, Obesity, and Metabolism, Division of Endocrinology, Diabetes, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Don Baldwin
- Pathonomics LLC, Suite 200, 3160 Chestnut St., Philadelphia, PA 19104, USA
| | - Andreas Prokesch
- Institute for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, Graz 8010, Austria
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, Graz 8010, Austria
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146
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Xu X, So JS, Park JG, Lee AH. Transcriptional control of hepatic lipid metabolism by SREBP and ChREBP. Semin Liver Dis 2013; 33:301-11. [PMID: 24222088 PMCID: PMC4035704 DOI: 10.1055/s-0033-1358523] [Citation(s) in RCA: 195] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The liver is a central organ that controls systemic energy homeostasis and nutrient metabolism. Dietary carbohydrates and lipids, and fatty acids derived from adipose tissue are delivered to the liver, and utilized for gluconeogenesis, lipogenesis, and ketogenesis, which are tightly regulated by hormonal and neural signals. Hepatic lipogenesis is activated primarily by insulin that is secreted from the pancreas after a high-carbohydrate meal. Sterol regulatory element binding protein-1c (SREBP-1c) and carbohydrate-responsive element-binding protein (ChREBP) are major transcriptional regulators that induce key lipogenic enzymes to promote lipogenesis in the liver. Sterol regulatory element binding protein-1c is activated by insulin through complex signaling cascades that control SREBP-1c at both transcriptional and posttranslational levels. Carbohydrate-responsive element-binding protein is activated by glucose independently of insulin. Here, the authors attempt to summarize the current understanding of the molecular mechanism for the transcriptional regulation of hepatic lipogenesis, focusing on recent studies that explore the signaling pathways controlling SREBPs and ChREBP.
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Affiliation(s)
| | | | | | - Ann-Hwee Lee
- To whom correspondence should be addressed: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA. , Tel: 1-212-746-9087
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147
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Cignarelli A, Giorgino F, Vettor R. Pharmacologic agents for type 2 diabetes therapy and regulation of adipogenesis. Arch Physiol Biochem 2013; 119:139-50. [PMID: 23724947 DOI: 10.3109/13813455.2013.796996] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The close link between type 2 diabetes and excess body weight highlights the need to consider the effects on weight of different treatments used for correction of hyperglycaemia. Indeed, specific currently available diabetes therapies can cause weight gain, including insulin and its analogues, sulphonylureas, and thiazolidinediones, while others, such as metformin and the GLP-1 receptor agonists, can promote weight loss. Excess body weight in patients with diabetes is largely due to expansion of adipose tissue, and these drugs could interfere with the mechanisms underlying the expansion and differentiation of adipocyte precursors. Almost all anti-diabetes drugs could also potentially affect adipocyte metabolism directly, by modulating lipogenesis, lipolysis, and fat oxidation. This review will examine the available evidence for specific effects of various anti-diabetes drugs on adipose tissue development and function with the ultimate goal of increasing our understanding of how pharmacological agents can modulate energy balance and body fat.
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Affiliation(s)
- A Cignarelli
- Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology, and Metabolic Diseases, University of Bari "Aldo Moro" , Bari , Italy and
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148
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Kostapanos MS, Kei A, Elisaf MS. Current role of fenofibrate in the prevention and management of non-alcoholic fatty liver disease. World J Hepatol 2013; 5:470-478. [PMID: 24073298 PMCID: PMC3782684 DOI: 10.4254/wjh.v5.i9.470] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 07/24/2013] [Accepted: 08/20/2013] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a common health problem with a high mortality burden due to its liver- and vascular-specific complications. It is associated with obesity, high-fat diet as well as with type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). Impaired hepatic fatty acid (FA) turnover together with insulin resistance are key players in NAFLD pathogenesis. Peroxisome proliferator-activated receptors (PPARs) are involved in lipid and glucose metabolic pathways. The novel concept is that the activation of the PPARα subunit may protect from liver steatosis. Fenofibrate, by activating PPARα, effectively improves the atherogenic lipid profile associated with T2DM and MetS. Experimental evidence suggested various protective effects of the drug against liver steatosis. Namely, fenofibrate-related PPARα activation may enhance the expression of genes promoting hepatic FA β-oxidation. Furthermore, fenofibrate reduces hepatic insulin resistance. It also inhibits the expression of inflammatory mediators involved in non-alcoholic steatohepatitis pathogenesis. These include tumor necrosis factor-α, intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1. Consequently, fenofibrate can limit hepatic macrophage infiltration. Other liver-protective effects include decreased oxidative stress and improved liver microvasculature function. Experimental studies showed that fenofibrate can limit liver steatosis associated with high-fat diet, T2DM and obesity-related insulin resistance. Few studies showed that these benefits are also relevant even in the clinical setting. However, these have certain limitations. Namely, these were uncontrolled, their sample size was small, fenofibrate was used as a part of multifactorial approach, while histological data were absent. In this context, there is a need for large prospective studies, including proper control groups and full assessment of liver histology.
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149
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Leptin's Pro-Angiogenic Signature in Breast Cancer. Cancers (Basel) 2013; 5:1140-62. [PMID: 24202338 PMCID: PMC3795383 DOI: 10.3390/cancers5031140] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 07/23/2013] [Accepted: 08/30/2013] [Indexed: 12/29/2022] Open
Abstract
Obesity is linked to increased incidence of breast cancer. The precise causes and mechanisms of these morbid relationships are unknown. Contradictory data on leptin angiogenic actions have been published. However, accumulating evidence would suggest that leptin’s pro-angiogenic effects in cancer play an essential role in the disease. Leptin, the main adipokine secreted by adipose tissue, is also abnormally expressed together with its receptor (OB-R) by breast cancer cells. Leptin induces proliferation and angiogenic differentiation of endothelial cells upregulates VEGF/VEGFR2 and transactivates VEGFR2 independent of VEGF. Leptin induces two angiogenic factors: IL-1 and Notch that can increase VEGF expression. Additionally, leptin induces the secretion and synthesis of proteases and adhesion molecules needed for the development of angiogenesis. Leptin’s paracrine actions can further affect stromal cells and tumor associated macrophages, which express OB-R and secrete VEGF and IL-1, respectively. A complex crosstalk between leptin, Notch and IL-1 (NILCO) that induces VEGF/VEGFR2 is found in breast cancer. Leptin actions in tumor angiogenesis could amplify, be redundant and/or compensatory to VEGF signaling. Current failure of breast cancer anti-angiogenic therapies emphasizes the necessity of targeting the contribution of other pro-angiogenic factors in breast cancer. Leptin’s impact on tumor angiogenesis could be a novel target for breast cancer, especially in obese patients. However, more research is needed to establish the importance of leptin in tumor angiogenesis. This review is focused on updated information on how leptin could contribute to tumor angiogenesis.
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150
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Pathak RR, Grover A, Malaney P, Quarni W, Pandit A, Allen-Gipson D, Davé V. Loss of phosphatase and tensin homolog (PTEN) induces leptin-mediated leptin gene expression: feed-forward loop operating in the lung. J Biol Chem 2013; 288:29821-35. [PMID: 23963458 DOI: 10.1074/jbc.m113.481523] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Elevated levels of systemic and pulmonary leptin are associated with diseases related to lung injury and lung cancer. However, the role of leptin in lung biology and pathology, including the mechanism of leptin gene expression in the pathogenesis of lung diseases, including lung cancer, remains elusive. Here, using conditional deletion of tumor suppressor gene Pten in the lung epithelium in vivo in transgenic mice and human PTEN-null lung epithelial cells, we identify the leptin-driven feed-forward signaling loop in the lung epithelial cells. Leptin-mediated leptin/leptin-receptor gene expression likely amplifies leptin signaling that may contribute to the pathogenesis and severity of lung diseases, resulting in poor clinical outcomes. Loss of Pten in the lung epithelial cells in vivo activated adipokine signaling and induced leptin synthesis as ascertained by genome-wide mRNA profiling and pathway analysis. Leptin gene transcription was mediated by binding of transcription factors NRF-1 and CCAAT/enhancer-binding protein δ (C/EBP) to the proximal promoter regions and STAT3 to the distal promoter regions as revealed by leptin promoter-mutation, chromatin immunoprecipitation, and gain- and loss-of-function studies in lung epithelial cells. Leptin treatment induced expression of the leptin/leptin receptor in the lung epithelial cells via activation of MEK/ERK, PI3K/AKT/mammalian target of rapamycin (mTOR), and JAK2/STAT3 signaling pathways. Expression of constitutively active MEK-1, AKT, and STAT3 proteins increased expression, and treatment with MEK, PI3K, AKT, and mTOR inhibitors decreased LEP expression, indicating that leptin via MAPK/ERK1/2, PI3K/AKT/mTOR, and JAK2/STAT3 pathways, in turn, further induces its own gene expression. Thus, targeted inhibition of the leptin-mediated feed-forward loop provides a novel rationale for pharmacotherapy of disease associated with lung injury and remodeling, including lung cancer.
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Affiliation(s)
- Ravi Ramesh Pathak
- From the Department of Pathology and Cell Biology, Morsani College of Medicine
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