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C-Jun/C7ORF41/NF-κB axis mediates hepatic inflammation and lipid accumulation in NAFLD. Biochem J 2020; 477:691-708. [PMID: 31957809 DOI: 10.1042/bcj20190799] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 02/06/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is an expanding health problem worldwide. Although many studies have made great efforts to elucidate the pathogenesis of NAFLD, the molecular basis remains poorly understood. Here, we showed that hepatic C7ORF41, a critical regulator of innate immune response, was markedly decreased in diet or genetic-induced NAFLD model. We also demonstrated that C7ORF41 overexpression significantly ameliorated hepatic inflammation and lipid accumulation in palmitic acid (PA)-treated hepatocytes, whereas C7ORF41 knockdown showed the opposite effects. Mechanistically, we found the anti-inflammatory role of C7ORF41 was attributed to the suppression of NF-κB p65-mediated induction of inflammatory cytokines. Moreover, we demonstrated that the suppression of C7ORF41 expression in hepatocytes is due to JNK activation, which promotes c-Jun-mediated transcriptional repression of C7ORF41. In conclusion, our findings suggested that a c-Jun/C7ORF41/NF-κB regulatory network controls the inflammatory response and lipid accumulation in NAFLD and may benefit the development of novel and promising therapeutic targets for NAFLD.
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The Opposite Effect of c-Jun Transcription Factor on Apolipoprotein E Gene Regulation in Hepatocytes and Macrophages. Int J Mol Sci 2019; 20:ijms20061471. [PMID: 30909560 PMCID: PMC6471215 DOI: 10.3390/ijms20061471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 12/15/2022] Open
Abstract
Apolipoprotein E (apoE) is mainly secreted by hepatocytes and incorporated into most plasma lipoproteins. Macrophages, which accumulate cholesterol and are critical for the development of the atherosclerotic plaque, are also an important, albeit smaller, apoE source. Distal regulatory elements control cell-specific activity of the apoE promoter: multienhancers (ME.1/2) in macrophages and hepatic control regions (HCR-1/2) in hepatocytes. A member of AP-1 cell growth regulator, c-Jun regulates the transcription of various apolipoproteins and proinflammatory molecules implicated in atherosclerosis. We aimed to investigate the effect of c-Jun on apoE expression in macrophages versus hepatocytes and to reveal the underlying molecular mechanisms. Herein we show that c-Jun had an opposite, cell-specific effect on apoE expression: downregulation in macrophages but upregulation in hepatocytes. Transient transfections using ME.2 deletion mutants and DNA pull-down (DNAP) assays showed that the inhibitory effect of c-Jun on the apoE promoter in macrophages was mediated by a functional c-Jun binding site located at 301/311 on ME.2. In hepatocytes, c-Jun overexpression strongly increased apoE expression, and this effect was due to c-Jun binding at the canonical site located at -94/-84 on the apoE proximal promoter, identified by transient transfections using apoE deletion mutants, DNAP, and chromatin immunoprecipitation assays. Overall, the dual effect of c-Jun on apoE gene expression led to decreased cholesterol efflux in macrophages resident in the atherosclerotic plaque synergized with an increased level of systemic apoE secreted by the liver to exacerbate atherogenesis.
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Effect of silibinin on CFLAR-JNK pathway in oleic acid-treated HepG2 cells. Biomed Pharmacother 2018; 108:716-723. [PMID: 30248539 DOI: 10.1016/j.biopha.2018.09.089] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/15/2018] [Accepted: 09/16/2018] [Indexed: 02/08/2023] Open
Abstract
AIMS Silibinin is a flavonolignan from milk thistle with many pharmacological activities including lipid-lowering and antioxidant. Caspase 8 and Fas-associated protein with death domain-like apoptosis regulator (CFLAR) is an important target gene in regulating non-alcoholic steatohepatitis (NASH). At present, the effect of silibinin on CFLAR-JNK pathway related to NASH was unknown. Here the effect of silibinin on CFLAR-JNK pathway and its downstream target genes involved in lipid metabolism, glucose uptake, oxidative stress and inflammatory response were studied in oleic acid (OA)-treated HepG2 cells. MAIN METHODS OA-treated HepG2 cells were employed as a in vitro model of steatosis, insulin resistance and oxidative stress. The model cells were then treated by silibinin (5, 20, 50, and 100 μM) for 24 h and detected for the related indicators as follows: (1) cellular triglycerides (TG), nitric oxide (NO) and glucose uptake; (2) the mRNA levels of the sterol regulatory element binding protein-1C (SREBP-1C), patatin-like phospholipase domain containing 3 (PNPLA3) and peroxisome proliferator activated receptor-α (PPARα); (3) the protein levels of PPARα, SREBP-1C, PNPLA3, CFLAR, phosphorylated c-Jun N-terminal kinase (pJNK), phosphatidylinositol 3-kinase (PI3K), phosphorylated serine-threonine protein kinase (pAKT), nuclear factor E2-related factor 2 (NRF2), cytochrome P450 2E1 (CYP2E1) and 4A (CYP4A). KEY FINDINGS Compared to the control, OA-treatment led to a result as follows: (1) increased the intracellular levels of TG and NO; (2) up-regulated the protein expression of SREBP-1C, PNPLA3, pJNK, CYP 2E1 and CYP 4A; (3) decreased the uptake of 2-NBDG; (4) down-regulated the protein expression of CFLAR, PPARα, PI3K, pAKT and NRF2. Compared to OA-treated HepG2 cells, silibinin treatment could improve the indicators as follows: (1) decreased the intracellular levels of TG and NO; (2) down-regulated the protein expression of SREBP-1C, PNPLA3, pJNK, CYP 2E1 and CYP 4A; (3) increased the uptake of 2-NBDG; (4) up-regulated the protein expression of CFLAR, PPARα, PI3K, pAKT and NRF2. SIGNIFICANCE Silibinin can ameliorate some metabolic alterations and induce some molecular changes by activating the CFLAR-JNK pathway and thereby regulating its downstream target genes involved in lipid metabolism (PPARα, SREBP-1C and PNPLA3), glucose uptake (PI3K-AKT), oxidative stress (NRF2, CYP2E1, CYP4A) and inflammatory response(NO) in OA-treated HepG2 cells demonstrating its possible use in ameliorating various symptoms of NASH.
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Testosterone Deficiency Induces Changes of the Transcriptomes of Visceral Adipose Tissue in Miniature Pigs Fed a High-Fat and High-Cholesterol Diet. Int J Mol Sci 2016; 17:ijms17122125. [PMID: 27999286 PMCID: PMC5187925 DOI: 10.3390/ijms17122125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/08/2016] [Accepted: 12/12/2016] [Indexed: 12/14/2022] Open
Abstract
Testosterone deficiency causes fat deposition, particularly in visceral fat, and its replacement might reverse fat accumulation, however, the underlying mechanisms of such processes under diet-induced adiposity are largely unknown. To gain insights into the genome-wide role of androgen on visceral adipose tissue (VAT), RNA-Seq was used to investigate testosterone deficiency induced changes of VAT in miniature pigs fed a high-fat and high-cholesterol (HFC) diet among intact male pigs (IM), castrated male pigs (CM), and castrated male pigs with testosterone replacement (CMT) treatments. The results showed that testosterone deficiency significantly increased VAT deposition and serum leptin concentrations. Moreover, a total of 1732 differentially expressed genes (DEGs) were identified between any two groups. Compared with gene expression profiles in IM and CMT pigs, upregulated genes in CM pigs, i.e., LOC100520753 (CD68), LCN2, EMR1, S100A9, NCF1 (p47phox), and LEP, were mainly involved in inflammatory response, oxidation-reduction process, and lipid metabolic process, while downregulated genes in CM pigs, i.e., ABHD5, SPP1, and GAS6, were focused on cell differentiation and cell adhesion. Taken together, our study demonstrates that testosterone deficiency alters the expression of numerous genes involved in key biological processes of VAT accumulation under HFC diet and provides a novel genome-wide view on the role of androgen on VAT deposition under HFC diet, thus improving our understanding of the molecular mechanisms involved in VAT changes induced by testosterone deficiency.
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Tsompanidis A, Vafiadaki E, Blüher S, Kalozoumi G, Sanoudou D, Mantzoros CS. Ciliary neurotrophic factor upregulates follistatin and Pak1, causes overexpression of muscle differentiation related genes and downregulation of established atrophy mediators in skeletal muscle. Metabolism 2016; 65:915-25. [PMID: 27173470 DOI: 10.1016/j.metabol.2016.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 03/01/2016] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
Abstract
INTRODUCTION The Ciliary Neurotrophic Factor (CNTF) is a pluripotent cytokine with anorexigenic actions in the hypothalamus that improves insulin sensitivity, increases energy expenditure and induces weight loss. Since CNTF also has an established myotrophic role, we sought to examine whether skeletal muscle contributes to the CNTF-induced metabolic improvement and identify the molecular mechanisms mediating these effects. METHODS We used a mouse model of diet-induced obesity, to which high or low CNTF doses were administered for 7days. Whole transcriptome expression levels were analyzed in dissected soleus muscles using microarrays and data were then confirmed using qRT-PCR. RESULTS We demonstrate that CNTF administration significantly downregulates leptin, while it upregulates follistatin and Pak1; a molecule associated with insulin sensitization in skeletal muscle. A significant overexpression of muscle differentiation related genes and downregulation of established atrophy mediators was observed. CONCLUSIONS The overall gene expression changes suggest an indirect, beneficial effect of CNTF on metabolism, energy expenditure and insulin sensitivity, exerted by the pronounced stimulation of muscle growth, with similarities to the described effect of follistatin and the activation of the Akt pathway in skeletal muscle.
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Affiliation(s)
- Alexandros Tsompanidis
- Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Susann Blüher
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Georgia Kalozoumi
- Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Despina Sanoudou
- Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece; Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Wang X, Bu HF, Liu SXL, De Plaen IG, Tan XD. Molecular Mechanisms Underlying the Regulation of the MFG-E8 Gene Promoter Activity in Physiological and Inflammatory Conditions. J Cell Biochem 2016; 116:1867-79. [PMID: 25711369 DOI: 10.1002/jcb.25142] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/17/2015] [Indexed: 12/15/2022]
Abstract
Milk fat globule-EGF factor 8 (MFG-E8) is expressed by macrophages and plays an important role in attenuating inflammation and maintaining tissue homeostasis. Previously, we and others found that lipopolysaccharide (LPS) inhibits MFG-E8 gene expression in macrophages. Here, we characterized the 5'-flanking region of the mouse MFG-E8 gene. To functionally analyze the upstream regulatory region of the MFG-E8 gene, a series of luciferase reporter gene constructs containing deleted or mutated regulatory elements were prepared. Using the luciferase assay, we revealed that Sp1 binding motifs within the proximal promoter region were necessary for full activity of the MFG-E8 promoter, whereas AP-1 like binding sequence at -372 played a role in governing the promoter activity at a homeostatic level. With chromatin immunoprecipitation assay, we showed that Sp1 and c-Jun physically interact with the MFG-E8 promoter region in vivo. In addition, Sp1 was found to regulate the MFG-E8 promoter activity positively and c-Jun negatively. Furthermore, we demonstrated that LPS inhibited MFG-E8 promoter activity via targeting Sp1 and AP-1-like motifs in the 5'-flanking region. Collectively, our data indicate that Sp1 and AP-1-related factors are involved in the regulation of MFG-E8 gene transcription by targeting their binding sites in the 5'-flanking region under physiological and inflammatory states.
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Affiliation(s)
- Xiao Wang
- Center for Intestinal and Liver Inflammation Research, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Heng-Fu Bu
- Center for Intestinal and Liver Inflammation Research, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Shirley X L Liu
- Center for Intestinal and Liver Inflammation Research, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Isabelle G De Plaen
- Center for Intestinal and Liver Inflammation Research, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Xiao-Di Tan
- Center for Intestinal and Liver Inflammation Research, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Research & Development, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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Screening a mouse liver gene expression compendium identifies modulators of the aryl hydrocarbon receptor (AhR). Toxicology 2015. [PMID: 26215100 DOI: 10.1016/j.tox.2015.07.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the biological and toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), dioxin-like compounds (DLC) as well as some drugs and endogenous tryptophan metabolites. Short-term activation of AhR can lead to hepatocellular steatosis, and chronic activation can lead to liver cancer in mice and rats. Analytical approaches were developed to identify biosets in a genomic database in which AhR activity was altered. A set of 63 genes was identified (the AhR gene expression biomarker) that was dependent on AhR for regulation after exposure to TCDD or benzo[a]pyrene and includes the known AhR targets Cyp1a1 and Cyp1b1. A fold-change rank-based test (Running Fisher's test; p-value ≤ 10(-4)) was used to evaluate the similarity between the AhR biomarker and a test set of 37 and 41 biosets positive or negative, respectively for AhR activation. The test resulted in a balanced accuracy of 95%. The rank-based test was used to identify factors that activate or suppress AhR in an annotated mouse liver/mouse primary hepatocyte gene expression database of ∼ 1850 comparisons. In addition to the expected activation of AhR by TCDD and DLC, AhR was activated by AP20189 and phenformin. AhR was suppressed by phenobarbital and 1,4-Bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) in a constitutive activated receptor (CAR)-dependent manner and pregnenolone-16α-carbonitrile in a pregnane X receptor (PXR)-dependent manner. Inactivation of individual genes in nullizygous models led to AhR activation (Pxr, Ghrhr, Taf10) or suppression (Ahr, Ilst6st, Hnf1a). This study describes a novel screening strategy for identifying factors in mouse liver that perturb AhR in a gene expression compendium.
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Bosma M, Dapito DH, Drosatos-Tampakaki Z, Huiping-Son N, Huang LS, Kersten S, Drosatos K, Goldberg IJ. Sequestration of fatty acids in triglycerides prevents endoplasmic reticulum stress in an in vitro model of cardiomyocyte lipotoxicity. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1841:1648-55. [PMID: 25251292 DOI: 10.1016/j.bbalip.2014.09.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/31/2014] [Accepted: 09/15/2014] [Indexed: 12/14/2022]
Abstract
We used human cardiomyocyte-derived cells to create an in vitro model to study lipid metabolism and explored the effects of PPARγ; ACSL1 and ATGL on fatty acid-induced ER stress. Compared to oleate, palmitate treatment resulted in less intracellular accumulation of lipid droplets and more ER stress, as measured by upregulation of CHOP, ATF6 and GRP78 gene expression and phosphorylation of eukaryotic initiation factor 2a (EIF2a). Both ACSL1 and PPARγ adenovirus-mediated expression augmented neutral lipid accumulation and reduced palmitate-induced upregulation of ER stress markers to levels similar to those in the oleate and control treatment groups. This suggests that increased channeling of non-esterified free fatty acids (NEFA) towards storage in the form of neutral lipids in lipid droplets protects against palmitate-induced ER stress. Overexpression of ATGL in cells incubated with oleate-containing medium increased NEFA release and stimulated expression of ER stress markers. Thus, inefficient creation of lipid droplets as well greater release of stored lipids induces ER stress.
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Fotakis P, Vezeridis A, Dafnis I, Chroni A, Kardassis D, Zannis VI. apoE3[K146N/R147W] acts as a dominant negative apoE form that prevents remnant clearance and inhibits the biogenesis of HDL. J Lipid Res 2014; 55:1310-23. [PMID: 24776540 DOI: 10.1194/jlr.m048348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Indexed: 12/11/2022] Open
Abstract
The K146N/R147W substitutions in apoE3 were described in patients with a dominant form of type III hyperlipoproteinemia. The effects of these mutations on the in vivo functions of apoE were studied by adenovirus-mediated gene transfer in different mouse models. Expression of the apoE3[K146N/R147W] mutant in apoE-deficient (apoE(-/-)) or apoA-I-deficient (apoA-I(-/-))×apoE(-/-) mice exacerbated the hypercholesterolemia and increased plasma apoE and triglyceride levels. In apoE(-/-) mice, the apoE3[K146N/R147W] mutant displaced apoA-I from the VLDL/LDL/HDL region and caused the accumulation of discoidal apoE-containing HDL. The WT apoE3 cleared the cholesterol of apoE(-/-) mice without induction of hypertriglyceridemia and promoted formation of spherical HDL. A unique property of the truncated apoE3[K146N/R147W]202 mutant, compared with similarly truncated apoE forms, is that it did not correct the hypercholesterolemia. The contribution of LPL and LCAT in the induction of the dyslipidemia was studied. Treatment of apoE(-/-) mice with apoE3[K146N/R147W] and LPL corrected the hypertriglyceridemia, but did not prevent the formation of discoidal HDL. Treatment with LCAT corrected hypertriglyceridemia and generated spherical HDL. The combined data indicate that the K146N/R147W substitutions convert the full-length and the truncated apoE3[K146N/R147W] mutant into a dominant negative ligand that prevents receptor-mediated remnant clearance, exacerbates the dyslipidemia, and inhibits the biogenesis of HDL.
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Affiliation(s)
- Panagiotis Fotakis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118 Department of BiochemistryUniversity of Crete Medical School, Heraklion, Crete, Greece 71110 Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Crete, Greece 71003
| | - Alexander Vezeridis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118
| | - Ioannis Dafnis
- National Center for Scientific Research "Demokritos" Athens, Greece 15310
| | - Angeliki Chroni
- National Center for Scientific Research "Demokritos" Athens, Greece 15310
| | - Dimitris Kardassis
- Department of BiochemistryUniversity of Crete Medical School, Heraklion, Crete, Greece 71110 Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Crete, Greece 71003
| | - Vassilis I Zannis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118
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Li F, Jiang C, Larsen MC, Bushkofsky J, Krausz KW, Wang T, Jefcoate CR, Gonzalez FJ. Lipidomics reveals a link between CYP1B1 and SCD1 in promoting obesity. J Proteome Res 2014; 13:2679-87. [PMID: 24684199 PMCID: PMC4018097 DOI: 10.1021/pr500145n] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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Cytochrome
P450 1B1 (CYP1B1) is involved in the metabolism of xenobiotic
compounds and endogenous metabolites. Disruption of Cyp1b1 in mice results in suppression of high-fat diet (HFD)-induced obesity
and an extensive change in hepatic energy regulation despite minimal
constitutive expression of CYP1B1 in hepatocytes. Lack of CYP1B1 is
correlated with altered lipid metabolism, especially lysophosphatidylcholines,
contributing to protection against obesity. Ultraperformance liquid
chromatography coupled to electrospray ionization quadrupole mass
spectrometry (UPLC-ESI-QTOFMS)-based metabolomics revealed lysophosphatidylcholine
18:0 (LPC 18:0) as a biomarker positively related to HFD-induced obesity.
The increased serum LPC 18:0 in wild-type mice is reduced in Cyp1b1-null mice on a HFD, which is reversed in CYP1B1-humanized mice. CYP1B1-humanized
mice show higher diet-induced obesity compared with Cyp1b1-null mice, suggesting that human CYP1B1 shows a similar response
to HFD as mouse Cyp1b1. In addition, hepatic stearoyl-CoA desaturase
1 (SCD1) expression was decreased in Cyp1b1-null
mice, and the attenuated diet-induced obesity and lower serum LPC
18:0 in the Cyp1b1-null mice is elevated after SCD1
overexpression, suggesting that SCD1 is correlated with CYP1B1-induced
obesity. These studies establish a biochemical link between cytochromes
P450, lipids, and metabolic disorders and suggest that inhibition
of CYP1B1 could be target for antiobesity drugs.
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Affiliation(s)
- Fei Li
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda, Maryland 20892, United States
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Drosatos-Tampakaki Z, Drosatos K, Siegelin Y, Gong S, Khan S, Van Dyke T, Goldberg IJ, Schulze PC, Schulze-Späte U. Palmitic acid and DGAT1 deficiency enhance osteoclastogenesis, while oleic acid-induced triglyceride formation prevents it. J Bone Miner Res 2014; 29:1183-95. [PMID: 24272998 PMCID: PMC4945760 DOI: 10.1002/jbmr.2150] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 11/01/2013] [Accepted: 11/16/2013] [Indexed: 01/03/2023]
Abstract
Both obesity and diabetes mellitus are associated with alterations in lipid metabolism as well as a change in bone homeostasis and osteoclastogenesis. We hypothesized that increased fatty acid levels affect bone health by altering precursor cell differentiation and osteoclast activation. Here we show that palmitic acid (PA, 16:0) enhances receptor activator of NF-κB ligand (RANKL)-stimulated osteoclastogenesis and is sufficient to induce osteoclast differentiation even in the absence of RANKL. TNFα expression is crucial for PA-induced osteoclastogenesis, as shown by increased TNFα mRNA levels in PA-treated cells and abrogation of PA-stimulated osteoclastogenesis by TNFα neutralizing antibodies. In contrast, oleic acid (OA, 18:1) does not enhance osteoclast differentiation, leads to increased intracellular triglyceride accumulation, and inhibits PA-induced osteoclastogenesis. Adenovirus-mediated expression of diacylglycerol acyl transferase 1 (DGAT1), a gene involved in triglyceride synthesis, also inhibits PA-induced osteoclastogenesis, suggesting a protective role of DGAT1 for bone health. Accordingly, Dgat1 knockout mice have larger bone marrow-derived osteoclasts and decreased bone mass indices. In line with these findings, mice on a high-fat PA-enriched diet have a greater reduction in bone mass and structure than mice on a high-fat OA-enriched diet. Thus, we propose that TNFα mediates saturated fatty acid-induced osteoclastogenesis that can be prevented by DGAT activation or supplementation with OA.
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Affiliation(s)
- Zoi Drosatos-Tampakaki
- Division of Periodontics, Columbia University College of Dental Medicine, New York, NY, USA
| | - Konstantinos Drosatos
- Division of Preventive Medicine and Nutrition, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Yasemin Siegelin
- Division of Periodontics, Columbia University College of Dental Medicine, New York, NY, USA
| | - Shan Gong
- Division of Periodontics, Columbia University College of Dental Medicine, New York, NY, USA
| | | | | | - Ira J Goldberg
- Division of Preventive Medicine and Nutrition, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - P Christian Schulze
- Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Ulrike Schulze-Späte
- Division of Periodontics, Columbia University College of Dental Medicine, New York, NY, USA
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Garcia-Arcos I, Hiyama Y, Drosatos K, Bharadwaj KG, Hu Y, Son NH, O'Byrne SM, Chang CL, Deckelbaum RJ, Takahashi M, Westerterp M, Obunike JC, Jiang H, Yagyu H, Blaner WS, Goldberg IJ. Adipose-specific lipoprotein lipase deficiency more profoundly affects brown than white fat biology. J Biol Chem 2013; 288:14046-14058. [PMID: 23542081 DOI: 10.1074/jbc.m113.469270] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adipose fat storage is thought to require uptake of circulating triglyceride (TG)-derived fatty acids via lipoprotein lipase (LpL). To determine how LpL affects the biology of adipose tissue, we created adipose-specific LpL knock-out (ATLO) mice, and we compared them with whole body LpL knock-out mice rescued with muscle LpL expression (MCK/L0) and wild type (WT) mice. ATLO LpL mRNA and activity were reduced, respectively, 75 and 70% in gonadal adipose tissue (GAT), 90 and 80% in subcutaneous tissue, and 84 and 85% in brown adipose tissue (BAT). ATLO mice had increased plasma TG levels associated with reduced chylomicron TG uptake into BAT and lung. ATLO BAT, but not GAT, had altered TG composition. GAT from MCK/L0 was smaller and contained less polyunsaturated fatty acids in TG, although GAT from ATLO was normal unless LpL was overexpressed in muscle. High fat diet feeding led to less adipose in MCK/L0 mice but TG acyl composition in subcutaneous tissue and BAT reverted to that of WT. Therefore, adipocyte LpL in BAT modulates plasma lipoprotein clearance, and the greater metabolic activity of this depot makes its lipid composition more dependent on LpL-mediated uptake. Loss of adipose LpL reduces fat accumulation only if accompanied by greater LpL activity in muscle. These data support the role of LpL as the "gatekeeper" for tissue lipid distribution.
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Affiliation(s)
- Itsaso Garcia-Arcos
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Yaeko Hiyama
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Konstantinos Drosatos
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Kalyani G Bharadwaj
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Yunying Hu
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Ni Huiping Son
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Sheila M O'Byrne
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Chuchun L Chang
- Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Richard J Deckelbaum
- Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Manabu Takahashi
- Department of Medicine, Jichii University, Tochigi 329-0498, Japan
| | - Marit Westerterp
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032; Department of Medical Biochemistry, University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Joseph C Obunike
- Department of Biological Sciences, New York City College of Technology, City University of New York, Brooklyn, New York 11201
| | - Hongfeng Jiang
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Hiroaki Yagyu
- Department of Medicine, Jichii University, Tochigi 329-0498, Japan
| | - William S Blaner
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Ira J Goldberg
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032.
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13
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Drosatos K, Drosatos-Tampakaki Z, Khan R, Homma S, Schulze PC, Zannis VI, Goldberg IJ. Inhibition of c-Jun-N-terminal kinase increases cardiac peroxisome proliferator-activated receptor alpha expression and fatty acid oxidation and prevents lipopolysaccharide-induced heart dysfunction. J Biol Chem 2011; 286:36331-9. [PMID: 21873422 DOI: 10.1074/jbc.m111.272146] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Septic shock results from bacterial infection and is associated with multi-organ failure, high mortality, and cardiac dysfunction. Sepsis causes both myocardial inflammation and energy depletion. We hypothesized that reduced cardiac energy production is a primary cause of ventricular dysfunction in sepsis. The JNK pathway is activated in sepsis and has also been implicated in impaired fatty acid oxidation in several tissues. Therefore, we tested whether JNK activation inhibits cardiac fatty acid oxidation and whether blocking JNK would restore fatty acid oxidation during LPS treatment. LPS treatment of C57BL/6 mice and adenovirus-mediated activation of the JNK pathway in cardiomyocytes inhibited peroxisome proliferator-activated receptor α expression and fatty acid oxidation. Surprisingly, none of the adaptive responses that have been described in other types of heart failure, such as increased glucose utilization, reduced αMHC:βMHC ratio or induction of certain microRNAs, occurred in LPS-treated mice. Treatment of C57BL/6 mice with a general JNK inhibitor (SP600125) increased fatty acid oxidation in mice and a cardiomyocyte-derived cell line. JNK inhibition also prevented LPS-mediated reduction in fatty acid oxidation and cardiac dysfunction. Inflammation was not alleviated in LPS-treated mice that received the JNK inhibitor. We conclude that activation of JNK signaling reduces fatty acid oxidation and prevents the peroxisome proliferator-activated receptor α down-regulation that occurs with LPS.
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Affiliation(s)
- Konstantinos Drosatos
- Division of Preventive Medicine and Nutrition, Columbia University College of Physicians and Surgeons, New York, New York, USA
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14
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Vezeridis AM, Drosatos K, Zannis VI. Molecular etiology of a dominant form of type III hyperlipoproteinemia caused by R142C substitution in apoE4. J Lipid Res 2010; 52:45-56. [PMID: 20861163 DOI: 10.1194/jlr.m008409] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have used adenovirus-mediated gene transfer in apolipoprotein (apo)E(-/-) mice to elucidate the molecular etiology of a dominant form of type III hyperlipoproteinemia (HLP) caused by the R142C substitution in apoE4. It was found that low doses of adenovirus expressing apoE4 cleared cholesterol, whereas comparable doses of apoE4[R142C] greatly increased plasma cholesterol, triglyceride, and apoE levels, caused accumulation of apoE in VLDL/IDL/LDL region, and promoted the formation of discoidal HDL. Co-expression of apoE4[R142C] with lecithin cholesterol acyltransferase (LCAT) or lipoprotein lipase (LPL) in apoE(-/-) mice partially corrected the apoE4[R142C]-induced dyslipidemia. High doses of C-terminally truncated apoE4[R142C]-202 partially cleared cholesterol in apoE(-/-) mice and promoted formation of discoidal HDL. The findings establish that apoE4[R142C] causes accumulation of apoE in VLDL/IDL/LDL region and affects in vivo the activity of LCAT and LPL, the maturation of HDL, and the clearance of triglyceride-rich lipoproteins. The prevention of apoE4[R142C]-induced dyslipidemia by deletion of the 203-299 residues suggests that, in the full-length protein, the R142C substitution may have altered the conformation of apoE bound to VLDL/IDL/LDL in ways that prevent triglyceride hydrolysis, cholesterol esterification, and receptor-mediated clearance in vivo.
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Affiliation(s)
- Alexander M Vezeridis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
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Iliopoulos D, Drosatos K, Hiyama Y, Goldberg IJ, Zannis VI. MicroRNA-370 controls the expression of microRNA-122 and Cpt1alpha and affects lipid metabolism. J Lipid Res 2010; 51:1513-23. [PMID: 20124555 DOI: 10.1194/jlr.m004812] [Citation(s) in RCA: 242] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We previously observed that treatment of mice with a dominant negative form of cJun (dn-cJun) increased the expression of genes involved in lipid metabolism and modulated the expression of nine microRNAs (miR). To investigate the potential effect of these miRs on the expression of the genes of lipid metabolism, we performed studies in cultured HepG2 cells. Transfection of HepG2 cells with sense or antisense miR-370 or miR-122 upregulated and downregulated, respectively, the transcription factor sterol-regulatory element binding protein 1c (SREBP-1c) and the enzymes diacylglycerol acyltransferase-2 (DGAT2), fatty acid synthase (FAS), and acyl-CoA carboxylase 1 (ACC1) that regulate fatty acid and triglyceride biosynthesis. The other seven miRs identified by the miR array screening did not affect the expression of lipogenic genes. miR-370 upregulated the expression of miR-122. Furthermore, the effect of miR-370 on the expression of the lipogenic genes was abolished by antisense miR-122. miR-370 targets the 3' untranslated region (UTR) of Cpt1alpha, and it downregulated the expression of the carnitine palmitoyl transferase 1alpha (Cpt1alpha) gene as well as the rate of beta oxidation. Our data suggest that miR-370 acting via miR-122 may have a causative role in the accumulation of hepatic triglycerides by modulating initially the expression of SREBP-1c, DGAT2, and Cpt1alpha and, subsequently, the expression of other genes that affect lipid metabolism.
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Affiliation(s)
- Dimitrios Iliopoulos
- Department of Biological Chemistry and Molecular Pharmacology, School of Medicine, Harvard University, Boston, MA, USA
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16
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Pocivavsek A, Rebeck GW. Inhibition of c-Jun N-terminal kinase increases apoE expression in vitro and in vivo. Biochem Biophys Res Commun 2009; 387:516-20. [PMID: 19615334 DOI: 10.1016/j.bbrc.2009.07.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 07/13/2009] [Indexed: 11/24/2022]
Abstract
Apolipoprotein E (apoE), a ligand for the low-density lipoprotein receptor family, has been implicated in modulating glial inflammatory responses and the risk of neurodegeneration associated with Alzheimer's disease. Glial cells activated by lipopolysaccharide (LPS) have decreased apoE levels and we recently showed that apoE itself can modulate the inflammatory response by reducing c-Jun N-terminal kinase (JNK) activation. Reduced JNK phosphorylation is vital to overcome the LPS-induced decrease in apoE expression, suggesting that JNK inhibition may be an effective way to increase apoE protein and protract its anti-inflammatory properties. This study investigates the impact of JNK inhibition on apoE production using two JNK inhibitors. Our work in primary glia and in vivo in mice injected with JNK inhibitor demonstrates that inhibition of JNK may be an effective way to increase apoE expression.
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Affiliation(s)
- Ana Pocivavsek
- Department of Neuroscience, Georgetown University, 3970 Reservoir Road NW, Washington, DC 20057-1464, USA
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17
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Calin MV, Manduteanu I, Dragomir E, Dragan E, Nicolae M, Gan AM, Simionescu M. Effect of depletion of monocytes/macrophages on early aortic valve lesion in experimental hyperlipidemia. Cell Tissue Res 2009; 336:237-48. [PMID: 19301037 DOI: 10.1007/s00441-009-0765-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 12/16/2008] [Indexed: 11/24/2022]
Abstract
Monocytes/macrophages are key players throughout atheroma development. The aim of this study was to determine the role of macrophages in lesion formation in heart valves in hyperlipidemia. We examined whether systemic depletion of monocytes/macrophages had a beneficial or adverse effect on the development of lesions in hyperlipemic hamsters injected twice weekly (for 2 months) with clodronate-encapsulated liposomes (H+Lclod), a treatment that selectively induces significant monocyte apoptosis. Hyperlipemic hamsters were employed as controls, as were hyperlipemic hamsters treated with plain liposomes. We assayed serum cholesterol (CH) and triglycerides (TG), the lipid and collagen contents and the size of the valve lesions, the matrix metalloproteinases (MMPs) in the serum and vessel wall, apolipoprotein E (ApoE), interleukin-1beta (IL-1beta), and superoxide anion production. In comparison with controls, H+Lclod hamsters exhibited: (1) increased lipid and collagen accumulation within the lesions, (2) decreased activity of MMP-9 and MMP-2 in sera and aortic homogenates, (3) decreased serum CH and TG and decreased expression of ApoE in sera and liver, (4) reduced expression of IL-1beta in aorta and liver homogenates, and (5) no change in the level of superoxide anion in the aorta. Thus, initially, the presence of the macrophages is beneficial in valvular lesion formation. Depletion of monocytes/macrophages is a two-edged sword having a beneficial effect by decreasing the expression of IL-1beta and MMP activities but an adverse effect by inducing a significant increase in the lipid and collagen content and expansion of valvular lesions.
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Affiliation(s)
- Manuela Voinea Calin
- Institute of Cellular Biology and Pathology Nicolae Simionescu, Bucharest, Romania.
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18
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Yang R, Trevillyan JM. c-Jun N-terminal kinase pathways in diabetes. Int J Biochem Cell Biol 2008; 40:2702-6. [PMID: 18678273 DOI: 10.1016/j.biocel.2008.06.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 06/27/2008] [Accepted: 06/30/2008] [Indexed: 01/30/2023]
Abstract
Type 2 diabetes develops from insulin resistance and has become a worldwide epidemic. The c-Jun N-terminal kinases have been considered as signaling molecules linking inflammation and insulin resistance. Genetic disruption of c-Jun N-terminal kinase-1 gene prevents the development of insulin resistance in obese and diabetic mice. Inhibition of c-Jun N-terminal kinases by a small cell-permeable peptide improves insulin sensitivity in mice. Hepatic inhibition of c-Jun N-terminal kinases using a dominant-negative protein or knockdown of c-Jun N-terminal kinase-1 gene by RNA interference reduces blood glucose and insulin levels and enhances hepatic insulin signaling in mice. Recent evidence demonstrates that the hepatic c-Jun N-terminal kinase pathway plays an important role in lipid and lipoprotein homeostasis in mice. This review discusses recent advances in our understanding of the role of c-Jun N-terminal kinase pathway in metabolic control and its potential as a target for the treatment of type 2 diabetes.
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Affiliation(s)
- Ruojing Yang
- Merck & Co. Inc., Metabolic Disorders, Rahway, NJ 07065, United States.
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19
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Bibliography. Current world literature. Lipid metabolism. Curr Opin Lipidol 2008; 19:314-21. [PMID: 18460925 DOI: 10.1097/mol.0b013e328303e27e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Chen C, Shah YM, Morimura K, Krausz KW, Miyazaki M, Richardson TA, Morgan ET, Ntambi JM, Idle JR, Gonzalez FJ. Metabolomics reveals that hepatic stearoyl-CoA desaturase 1 downregulation exacerbates inflammation and acute colitis. Cell Metab 2008; 7:135-47. [PMID: 18249173 PMCID: PMC2276699 DOI: 10.1016/j.cmet.2007.12.003] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 10/23/2007] [Accepted: 12/14/2007] [Indexed: 02/08/2023]
Abstract
To investigate the pathogenic mechanism of ulcerative colitis, a dextran sulfate sodium (DSS)-induced acute colitis model was examined by serum metabolomic analysis. Higher levels of stearoyl lysophosphatidylcholine and lower levels of oleoyl lysophosphatidylcholine in DSS-treated mice compared to controls led to the identification of DSS-elicited inhibition of stearoyl-CoA desaturase 1 (SCD1) expression in liver. This decrease occurred prior to the symptoms of acute colitis and was well correlated with elevated expression of proinflammatory cytokines. Furthermore, Citrobacter rodentium-induced colitis and lipopolysaccharide treatment also suppressed SCD1 expression in liver. Scd1 null mice were more susceptible to DSS treatment than wild-type mice, while oleic acid feeding and in vivo SCD1 rescue with SCD1 adenovirus alleviated the DSS-induced phenotype. This study reveals that inhibition of SCD1-mediated oleic acid biogenesis exacerbates proinflammatory responses to exogenous challenges, suggesting that SCD1 and its related lipid species may serve as potential targets for intervention or treatment of inflammatory diseases.
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Affiliation(s)
- Chi Chen
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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