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Novel use of acitretin for posttransplant Grover's disease and cutaneous graft versus host disease. JAAD Case Rep 2023; 33:67-69. [PMID: 36890866 PMCID: PMC9988423 DOI: 10.1016/j.jdcr.2023.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Confirmation of high-throughput screening data and novel mechanistic insights into FXR-xenobiotic interactions by orthogonal assays. Curr Res Toxicol 2022; 3:100092. [PMID: 36353521 PMCID: PMC9637864 DOI: 10.1016/j.crtox.2022.100092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/06/2022] [Accepted: 10/26/2022] [Indexed: 11/05/2022] Open
Abstract
Toxicology in the 21st Century (Tox21) is a federal collaboration employing a high-throughput robotic screening system to test 10,000 environmental chemicals. One of the primary goals of the program is prioritizing toxicity evaluations through in vitro high-throughput screening (HTS) assays for large numbers of chemicals already in commercial use for which little or no toxicity data is available. Within the Tox21 screening program, disruption in nuclear receptor (NR) signaling represents a particular area of interest. Given the role of NR's in modulating a wide range of biological processes, alterations of their activity can have profound biological impacts. Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily that has demonstrated importance in bile acid homeostasis, glucose metabolism, lipid homeostasis and hepatic regeneration. In this study, we re-evaluated 24 FXR agonists and antagonists identified through Tox21 using select orthogonal assays. In transient transactivation assays, 7/8 putative agonists and 4/4 putative inactive compounds were confirmed. Likewise, we confirmed 9/12 antagonists tested. Using a mammalian two hybrid approach we demonstrate that both FXR agonists and antagonists facilitate FXRα-coregulator interactions suggesting that differential coregulator recruitment may mediate activation/repression of FXRα mediated transcription. Additionally, we tested the ability of select FXR agonists and antagonists to facilitate hepatic transcription of FXR gene targets Shp and Bsep in a teleost (Medaka) model. Through application of in vitro cell-based assays, in silico modeling and in vivo gene expressions, we demonstrated the molecular complexity of FXR:ligand interactions and confirmed the ability of diverse ligands to modulate FXRα, facilitate differential coregulator recruitment and activate/repress receptor-mediated transcription. Overall, we suggest a multiplicative approach to assessment of nuclear receptor function may facilitate a greater understanding of the biological and mechanistic complexities of nuclear receptor activities and further our ability to interpret broad HTS outcomes.
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Key Words
- Bsep, bile salt export pump
- CDCA, chenodeoxycholic acid
- DMSO, dimethyl sulfoxide
- EPA, U.S. Environmental Protection Agency
- FXR, Farnesoid X receptor
- Farnesoid X receptor
- High-throughput screening
- M2H, mammalian two-hybrid
- Medaka
- RXR, retinoid X receptor
- Shp, small heterodimer partner
- Teleost models
- Tox21, Toxicology in the 21st Century
- ToxCast
- qHTS, quantitative high-throughput screening
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Retinoic acid promotes tissue vitamin A status and modulates adipose tissue metabolism of neonatal rats exposed to maternal high-fat diet-induced obesity. J Nutr Sci 2022; 11:e54. [PMID: 35836697 PMCID: PMC9274391 DOI: 10.1017/jns.2022.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/11/2022] [Accepted: 06/14/2022] [Indexed: 11/06/2022] Open
Abstract
Maternal obesity may compromise the micronutrient status of the offspring. Vitamin A (VA) is an essential micronutrient during neonatal development. Its active metabolite, retinoic acid (RA), is a key regulator of VA homeostasis, which also regulates adipose tissue (AT) development in obese adults. However, its role on VA status and AT metabolism in neonates was unknown and it was determined in the present study. Pregnant Sprague-Dawley rats were randomised to a normal fat diet (NFD) or a high fat diet (HFD). From postnatal day 5 (P5) to P20, half of the HFD pups received oral RA every 3 d (HFDRA group). NFD pups and the remaining HFD pups (HFD group) received placebo. Six hours after dosing on P8, P14 and P20, n 4 pups per group were euthanised for different measures. It was found that total retinol concentration in neonatal liver and lung was significantly lower in the HFD group than the NFD group, while the concentrations were significantly increased in the HFDRA group. The HFD group exhibited significantly higher body weight (BW) gain, AT mass, serum leptin and adiponectin, and gene expression of these adipokines in white adipose tissue compared with the NFD group; these measures were significantly reduced in the HFDRA group. BAT UCP2 and UCP3 gene expression were significantly higher in pups receiving RA. In conclusion, repeated RA treatment during the suckling period improved the tissue VA status of neonates exposed to maternal obesity. RA also exerted a regulatory effect on neonatal obesity development by reducing BW gain and adiposity and modulating AT metabolism.
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Key Words
- Adipose tissue
- BAT, brown adipose tissue
- BW, body weight
- HFD, high fat diet
- LRAT, lecithin:retinol acyltransferase
- Maternal obesity
- NFD, normal fat diet
- Neonatal lung
- Neonatal obesity
- Neonate
- P, postnatal
- RA, retinoic acid
- RAR, retinoic acid receptor
- RXR, retinoid X receptor
- Retinoic acid
- UCP, uncoupling protein
- UPLC, ultra-high-performance liquid chromatography
- VA, vitamin A
- Vitamin A
- WAT, white adipose tissue
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An overview on medicinal perspective of thiazolidine-2,4-dione: A remarkable scaffold in the treatment of type 2 diabetes. J Adv Res 2020; 23:163-205. [PMID: 32154036 PMCID: PMC7052407 DOI: 10.1016/j.jare.2020.01.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/07/2020] [Accepted: 01/18/2020] [Indexed: 12/26/2022] Open
Abstract
TZDs, an important pharmacophore in the treatment of diabetes. Various analog-based synthetic strategies and biological significance are discussed. Clinical studies using TZDs along with other antidiabetic agents are also highlighted. SAR has been discussed to suggest the interactions between derivatives and receptor sites. Pyrazole, chromone, and acid-based TZDs can be considered as potential lead molecules.
Diabetes or diabetes mellitus is a complex or polygenic disorder, which is characterized by increased levels of glucose (hyperglycemia) and deficiency in insulin secretion or resistance to insulin over an elongated period in the liver and peripheral tissues. Thiazolidine-2,4-dione (TZD) is a privileged scaffold and an outstanding heterocyclic moiety in the field of drug discovery, which provides various opportunities in exploring this moiety as an antidiabetic agent. In the past few years, various novel synthetic approaches had been undertaken to synthesize different derivatives to explore them as more potent antidiabetic agents with devoid of side effects (i.e., edema, weight gain, and bladder cancer) of clinically used TZD (pioglitazone and rosiglitazone). In this review, an effort has been made to summarize the up to date research work of various synthetic strategies for TZD derivatives as well as their biological significance and clinical studies of TZDs in combination with other category as antidiabetic agents. This review also highlights the structure-activity relationships and the molecular docking studies to convey the interaction of various synthesized novel derivatives with its receptor site.
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Key Words
- ADDP, 1,1′-(Azodicarbonyl)dipiperidine
- AF, activation factor
- ALP, alkaline phosphatase
- ALT, alanine transaminase
- AST, aspartate transaminase
- Boc, Butyloxycarbonyl
- DBD, DNA-binding domain
- DCM, dichloromethane
- DM, diabetes mellitus
- DMF, dimethylformamide
- DMSO, dimethyl sulfoxide
- DNA, deoxyribonucleic acid
- Diabetes
- E, Entgegen
- ECG, electrocardiogram
- FDA, food and drug administration
- FFA, free fatty acid
- GAL4, Galactose transporter type
- GLUT4, glucose transporter type 4
- GPT, glutamic pyruvic transaminase
- HCl, Hydrochloric Acid
- HDL, high-density lipoprotein
- HEK, human embryonic kidney
- HEp-2, Human epithelial type 2
- HFD, high-fat diet
- IDF, international diabetes federation
- IL-β, interlukin-beta
- INS-1, insulin-secreting cells
- K2CO3, Potassium carbonate
- KOH, potassium hydroxide
- LBD, ligand-binding domain
- LDL, low-density lipoprotein
- MDA, malondialdehyde
- NA, nicotinamide
- NBS, N-bromosuccinimide
- NFκB, nuclear factor kappa-B
- NO, nitric oxide
- NaH, Sodium Hydride
- OGTT, oral glucose tolerance test
- PDB, protein data bank
- PPAR, peroxisome-proliferator activated receptor
- PPAR-γ
- PPRE, peroxisome proliferator response element
- PTP1B, protein-tyrosine phosphatase 1B
- Pd, Palladium
- Pioglitazone
- QSAR, quantitative structure-activity relationship
- RXR, retinoid X receptor
- Rosiglitazone
- SAR, structure-activity relationship
- STZ, streptozotocin
- T2DM, type 2 diabetes mellitus
- TFA, trifluoroacetic acid
- TFAA, trifluoroacetic anhydride
- TG, triglycerides
- THF, tetrahydrofuran
- TNF-α, tumor necrosis factor-alpha
- TZD, thiazolidine-2,4-dione
- Thiazolidine-2,4-diones
- WAT, white adipose tissue
- Z, Zusammen
- i.m, Intramuscular
- mCPBA, meta-chloroperoxybenzoic acid
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Small molecules for fat combustion: targeting obesity. Acta Pharm Sin B 2019; 9:220-236. [PMID: 30976490 PMCID: PMC6438825 DOI: 10.1016/j.apsb.2018.09.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 08/01/2018] [Accepted: 08/22/2018] [Indexed: 12/11/2022] Open
Abstract
Obesity is increasing in an alarming rate worldwide, which causes higher risks of some diseases, such as type 2 diabetes, cardiovascular diseases, and cancer. Current therapeutic approaches, either pancreatic lipase inhibitors or appetite suppressors, are generally of limited effectiveness. Brown adipose tissue (BAT) and beige cells dissipate fatty acids as heat to maintain body temperature, termed non-shivering thermogenesis; the activity and mass of BAT and beige cells are negatively correlated with overweight and obesity. The existence of BAT and beige cells in human adults provides an effective weight reduction therapy, a process likely to be amenable to pharmacological intervention. Herein, we combed through the physiology of thermogenesis and the role of BAT and beige cells in combating with obesity. We summarized the thermogenic regulators identified in the past decades, targeting G protein-coupled receptors, transient receptor potential channels, nuclear receptors and miscellaneous pathways. Advances in clinical trials were also presented. The main purpose of this review is to provide a comprehensive and up-to-date knowledge from the biological importance of thermogenesis in energy homeostasis to the representative thermogenic regulators for treating obesity. Thermogenic regulators might have a large potential for further investigations to be developed as lead compounds in fighting obesity.
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Key Words
- AKT, protein kinase B
- ALDH9, aldehyde dehydrogenase 9
- AMPK, AMP-activated protein kinase
- ATP, adenosine triphosphate
- BA, bile acids
- BAT, brown adipose tissue
- BMP8b, bone morphogenetic protein 8b
- Beige cells
- Brown adipose tissue
- C/EBPα, CCAAT/enhancer binding protein α
- CLA, cis-12 conjugated linoleic acid
- CRABP-II, cellular RA binding protein type II
- CRE, cAMP response element
- Cidea, cell death-inducing DNA fragmentation factor α-like effector A
- Dio2, iodothyronine deiodinase type 2
- ERE, estrogen response element
- ERs, estrogen receptors
- FAS, fatty acid synthase
- FGF21, fibroblast growth factor 21
- GPCRs, G protein-coupled receptors
- HFD, high fat diet
- LXR, liver X receptors
- MAPK, mitogen-activated protein kinase
- OXPHOS, oxidative phosphorylation
- Obesity
- PDEs, phosphodiesterases
- PET-CT, positron emission tomography combined with computed tomography
- PGC-1α, peroxisome proliferator-activated receptor γ coactivator 1-α
- PKA, protein kinase A
- PPARs, peroxisome proliferator-activated receptors
- PPREs, peroxisome proliferator response elements
- PRDM16, PR domain containing 16
- PTP1B, protein-tyrosine phosphatase 1B
- PXR, pregnane X receptor
- RA, retinoic acid
- RAR, RA receptor
- RARE, RA response element
- RMR, resting metabolic rate
- RXR, retinoid X receptor
- SIRT1, silent mating type information regulation 2 homolog 1
- SNS, sympathetic nervous system
- TFAM, mitochondrial transcription factor A
- TMEM26, transmembrane protein 26
- TRPs, transient receptor potential cation channels
- Thermogenesis
- UCP1, uncoupling protein 1
- Uncoupling protein 1
- VDR, vitamin D receptor
- VDRE, VDR response elements
- WAT, white adipose tissue
- cAMP, cyclic adenosine monophosphate
- cGMP, cyclic guanosine monophosphate
- β3-AR, β3-adrenergic receptor
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Peroxisome Proliferator-Activated Receptors and Their Agonists in Nonalcoholic Fatty Liver Disease. J Clin Exp Hepatol 2019; 9:731-739. [PMID: 31889755 PMCID: PMC6926194 DOI: 10.1016/j.jceh.2019.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 06/23/2019] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. In addition to the liver-related morbidity and mortality, NAFLD is now also associated with various extrahepatic diseases. Pathogenesis of NAFLD is multifactorial with limited pharmacotherapy options for the treatment of patients with NAFLD. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that are involved in the transcriptional regulation of lipid metabolism, glucose homeostasis, energy balance, inflammation, and atherosclerosis. PPAR agonists are attractive options for treatment of NAFLD as they can act at multiple targets involved in the pathogenesis of NAFLD. We reviewed the available literature on the pathophysiological role of PPARs and use of PPAR agonists in the treatment of NAFLD. Original studies and review articles available on PubMed regarding the role of PPARs in the pathogenesis and utility of PPAR agonists in the treatment of NAFLD were included in this review article. ClinicalTrials.gov and Clinical Trials Registry-India sites were searched for ongoing studies on saroglitazar. The available literature suggests that PPARs play an important role in the pathogenesis of NAFLD. Use of PPAR gamma agonists is associated with histological improvement in NAFLD. Dual PPAR agonists with no or minimal PPAR gamma activity are being explored in the treatment of NAFLD. Because of the pathophysiological role of PPARs in NAFLD, PPAR agonists are attractive options for the treatment of patients with NAFLD. Dual PPAR agonists without significant gamma activity appear promising for the treatment of NAFLD.
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E17110 promotes reverse cholesterol transport with liver X receptor β agonist activity in vitro. Acta Pharm Sin B 2016; 6:198-204. [PMID: 27175330 PMCID: PMC4856951 DOI: 10.1016/j.apsb.2016.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/04/2016] [Accepted: 03/17/2016] [Indexed: 12/11/2022] Open
Abstract
Liver X receptor (LXR) plays an important role in reverse cholesterol transport (RCT), and activation of LXR could reduce atherosclerosis. In the present study we used a cell-based screening method to identify new potential LXRβ agonists. A novel benzofuran-2-carboxylate derivative was identified with LXRβ agonist activity: E17110 showed a significant activation effect on LXRβ with an EC50 value of 0.72 μmol/L. E17110 also increased the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) in RAW264.7 macrophages. Moreover, E17110 significantly reduced cellular lipid accumulation and promoted cholesterol efflux in RAW264.7 macrophages. Interestingly, we found that the key amino acids in the LXRβ ligand-binding domain had distinct interactions with E17110 as compared to TO901317. These results suggest that E17110 was identified as a novel compound with LXRβ agonist activity in vitro via screening, and could be developed as a potential anti-atherosclerotic lead compound.
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Key Words
- ABCA1
- ABCA1, ATP-binding cassette transporter A1
- ABCG1
- ABCG1, ATP-binding cassette transporter G1
- ApoA-I, apolipoprotein A-I
- Atherosclerosis
- Cholesterol efflux
- GAPDH, glyceraldehyde-phosphate dehydrogenase
- HDL, high-density lipoprotein
- LBD, ligand-binding domain
- LXR, liver X receptor
- LXRE, LXR response element
- LXRβ
- NR, nuclear receptor
- RCT, reverse cholesterol transport
- RXR, retinoid X receptor
- Reverse cholesterol transport
- ox-LDL, oxidized low-density lipoprotein
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Identification of liver CYP51 as a gene responsive to circulating cholesterol in a hamster model. J Nutr Sci 2016; 5:e16. [PMID: 27110359 PMCID: PMC4831128 DOI: 10.1017/jns.2016.3] [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: 11/24/2015] [Accepted: 01/05/2016] [Indexed: 12/17/2022] Open
Abstract
Hypercholesterolaemia is a risk factor for CVD, which is a leading cause of death in industrialised societies. The biosynthetic pathways for cholesterol metabolism are well understood; however, the regulation of circulating cholesterol by diet is still not fully elucidated. The present study aimed to gain more comprehensive understanding of the relationship between circulating cholesterol levels and molecular effects in target tissues using the hamster model. Male golden Syrian hamsters were fed with chow or diets containing 36 % energy from fat with or without 1 % cholesteyramine (CA) as a modulator of circulating cholesterol levels for 35 d. It was revealed that the expression of lanosterol 14α-demethylase (CYP51) instead of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression was responsive to circulating cholesterol in hamsters fed hypercholesterolaemic diets. The high-fat diet increased circulating cholesterol and down-regulated CYP51, but not HMG-CoA reductase. The CA diet decreased cholesterol and increased CYP51 expression, but HMG-CoA reductase expression was not affected. The high-fat diet and CA diet altered the expression level of cholesterol, bile acids and lipid metabolism-associated genes (LDL receptor, cholesterol 7α-hydroxylase (CYP7A1), liver X receptor (LXR) α, and ATP-binding cassette subfamily G member 5/8 (ABCG5/8)) in the liver, which were significantly correlated with circulating cholesterol levels. Correlation analysis also showed that circulating cholesterol levels were regulated by LXR/retinoid X receptor and PPAR pathways in the liver. Using the hamster model, the present study provided additional molecular insights into the influence of circulating cholesterol on hepatic cholesterol metabolism pathways during hypercholesterolaemia.
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Key Words
- ABCG5/, ATP-binding cassette subfamily G member 5/8
- CA, cholestyramine
- CYP51
- CYP51, lanosterol 14α-demethylase
- CYP7A1, cholesterol 7α-hydroxylase
- Circulating cholesterol
- HF + CA, high-fat + cholestyramine
- HF, high-fat
- HMG, 3-hydroxy-3-methyl-glutaryl
- Hamsters
- Hypercholesterolaemia
- IPA, Ingenuity Pathway Analysis
- LXRα, liver X receptor α
- RXR, retinoid X receptor
- SREBP, sterol regulatory element-binding protein
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Retinoid regulated macrophage cholesterol efflux involves the steroidogenic acute regulatory protein. Data Brief 2016; 7:940-5. [PMID: 27081671 PMCID: PMC4818342 DOI: 10.1016/j.dib.2016.03.055] [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: 11/06/2015] [Revised: 03/07/2016] [Accepted: 03/15/2016] [Indexed: 11/26/2022] Open
Abstract
Elimination of excess cholesteryl esters from macrophage-derived foam cells is known to be a key process in limiting plaque stability and progression of atherosclerotic lesions. We have recently demonstrated that regulation of retinoid mediated cholesterol efflux is influenced by liver X receptor (LXR) signaling in mouse macrophages (Manna, P.R. et al., 2015, Biochem. Biophys. Res. Commun., 464:312-317). The data presented in this article evaluate the importance of the steroidogenic acute regulatory protein (StAR) in retinoid mediated macrophage cholesterol efflux. Overexpression of StAR in mouse RAW 264.7 macrophages increased the effects of both all-trans retinoic acid (atRA) and 9-cis RA on cholesterol efflux, suggesting StAR enhances the efficacy of retinoic acid receptor (RAR) and/or retinoid X receptor (RXR) ligands. Additional data revealed that atRA enhances (Bu)2cAMP induced StAR and ATP-binding cassette transporter A1 protein levels. Treatment of macrophages transfected with an LXRE reporter plasmid (pLXREx3-Luc) was found to induce the effects of RAR and RXR analogs on LXR activity.
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Key Words
- (Bu)2cAMP, dibutyryl cAMP, RAR, retinoic acid receptor
- ABCA1
- ABCA1, ATP-binding cassette transporter A1
- Apo-A1, apolipoprotein A1
- Cholesterol efflux
- LXR, liver X receptor
- Macrophages
- RAR
- RXR
- RXR, retinoid X receptor
- Retinoids
- SREBP-1c, sterol regulatory element-binding protein 1c
- StAR
- StAR, steroidogenic acute regulatory protein
- atRA, all-trans RA
- retinoids, retinoic acid (RA) and its derivatives
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Inhibition of ASCT2 is essential in all-trans retinoic acid-induced reduction of adipogenesis in 3T3-L1 cells. FEBS Open Bio 2015; 5:571-8. [PMID: 26236584 PMCID: PMC4511454 DOI: 10.1016/j.fob.2015.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/21/2015] [Accepted: 06/28/2015] [Indexed: 01/07/2023] Open
Abstract
Asct2, an amino acid transporter, could be a target for obesity prevention and treatment. All-trans retinoic acid suppresses upregulation of Asct2 during adipogenesis of 3T3-L1 cells. The Asct2 inhibitor, l-γ-glutamyl-p-nitroanilide, suppresses adipogenesis at early time points. Treatment with l-γ-glutamyl-p-nitroanilide suppresses adipogenesis more effectively than l-glutamine-deficient conditions.
Vitamin A has preventive effects on obesity. All-trans retinoic acid (ATRA), the active form of vitamin A, inhibits lipid accumulation in 3T3-L1 cells in an experimental adipogenesis model. We found that ATRA suppressed up-regulation of the amino acid transporter, Asct2, in adipogenerating 3T3-L1 cells. We observed that Asct2 was up-regulated at 1 day after adipogenesis stimuli. The Asct2 inhibitor l-γ-glutamyl-p-nitroanilide (GPNA) decreased lipid accumulation. Glutamine-free conditions also suppressed adipogenesis. Suppression of adipogenesis by ATRA may be through Asct2 reduction. These results indicate that Asct2 could be a target for obesity prevention and treatment.
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Mechanism of the development of nonalcoholic steatohepatitis after pancreaticoduodenectomy. BBA CLINICAL 2015; 3:168-74. [PMID: 26674248 PMCID: PMC4661550 DOI: 10.1016/j.bbacli.2015.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/05/2015] [Accepted: 02/10/2015] [Indexed: 02/08/2023]
Abstract
Background and aim It is recognized that nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), may develop after pancreaticoduodenectomy (PD). However, the mechanism of NASH development remains unclear. This study aimed to examine the changes in gene expression associated with NASH occurrence following PD. Methods The expression of genes related to fatty acid/triglyceride (FA/TG) metabolism and inflammatory signaling was examined using liver samples obtained from 7 post-PD NASH patients and compared with 6 healthy individuals and 32 conventional NASH patients. Results The livers of post-PD NASH patients demonstrated significant up-regulation of the genes encoding CD36, FA-binding proteins 1 and 4, acetyl-coenzyme A carboxylase α, diacylglycerol acyltransferase 2, and peroxisome proliferator-activated receptor (PPAR) γ compared with normal and conventional NASH livers. Although serum apolipoprotein B (ApoB) and TG were decreased in post-PD NASH patients, the mRNAs of ApoB and microsomal TG transfer protein were robustly increased, indicating impaired TG export from the liver as very-low-density lipoprotein (VLDL). Additionally, elevated mRNA levels of myeloid differentiation primary response 88 and superoxide dismutases in post-PD NASH livers suggested significant activation of innate immune response and augmentation of oxidative stress generation. Conclusions Enhanced FA uptake into hepatocytes and lipogenesis, up-regulation of PPARγ, and disruption of VLDL excretion into the circulation are possible mechanisms of steatogenesis after PD. General significance These results provide a basis for understanding the pathogenesis of NAFLD/NASH following PD. The mechanism of NASH development after pancreaticoduodenectomy (PD) was unclear. The gene expression involved in fatty acid uptake and lipogenesis was increased. PPARγ and its target genes were up-regulated in post-PD NASH livers. Impaired triglyceride excretion from the liver was suggested in post-PD NASH. This study proposes possible mechanisms of steatogenesis after PD.
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Key Words
- ACACA, acetyl-CoA carboxylase α
- ACACB, acetyl-CoA carboxylase β
- ACADM, medium-chain acyl-CoA dehydrogenase
- ACOX1, acyl-CoA oxidase 1
- ALT, alanine aminotransferase
- AST, aspartate aminotransferase
- ApoB, apolipoprotein B
- BMI, body mass index
- CAT, catalase
- CPT1A, carnitine palmitoyl-CoA transferase 1α
- CT, computed tomography
- CYBB, cytochrome b-245 β polypeptide
- CYP, cytochrome P450
- CoA, coenzyme A
- DGAT, diacylglycerol acyltransferase
- FA, fatty acid
- FABP, fatty acid-binding protein
- FASN, fatty acid synthase
- Fatty acid
- HADHA, hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase α
- HBV, hepatitis B virus
- HCV, hepatitis C virus
- HOMA-IR, homeostasis model assessment for insulin resistance
- LPS, lipopolysaccharide
- LXR, liver X receptor
- MCD, methionine- and choline-deficient diet
- MTTP, microsomal triglyceride transfer protein
- MYD88, myeloid differentiation primary response 88
- MyD88
- NAFLD, nonalcoholic fatty liver disease
- NAS, NAFLD activity score
- NASH
- NASH, nonalcoholic steatohepatitis
- PD, pancreaticoduodenectomy
- PPAR, peroxisome proliferator-activated receptor
- PPARGC, PPARγ co-activator
- Pancreaticoduodenectomy
- ROS, reactive oxygen species
- RXR, retinoid X receptor
- SCD, stearoyl-CoA desaturase
- SOD, superoxide dismutase
- SREBF1, sterol regulatory element-binding transcription factor 1
- TG, triglyceride
- TGFB1, transforming growth factor β1
- TLR, Toll-like receptor
- TNF, tumor necrosis factor α
- US, ultrasonography
- VLDL
- VLDL, very-low-density lipoprotein
- qPCR, quantitative polymerase chain reaction
- γGT, gamma-glutamyltransferase
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Adaptive responses induced by 24S-hydroxycholesterol through liver X receptor pathway reduce 7-ketocholesterol-caused neuronal cell death. Redox Biol 2013; 2:28-35. [PMID: 24371802 PMCID: PMC3871289 DOI: 10.1016/j.redox.2013.11.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 02/05/2023] Open
Abstract
Lipid peroxidation products have been known to induce cellular adaptive responses and enhance tolerance against subsequent oxidative stress through up-regulation of antioxidant compounds and enzymes. 24S-hydroxycholesterol (24SOHC) which is endogenously produced oxysterol in the brain plays an important role in maintaining brain cholesterol homeostasis. In this study, we evaluated adaptive responses induced by brain-specific oxysterol 24SOHC in human neuroblastoma SH-SY5Y cells. Cells treated with 24SOHC at sub-lethal concentrations showed significant reduction in cell death induced by subsequent treatment with 7-ketocholesterol (7KC) in both undifferentiated and retinoic acid-differentiated SH-SY5Y cells. These adaptive responses were also induced by other oxysterols such as 25-hydroxycholesterol and 27-hydroxycholesterol which are known to be ligands of liver X receptor (LXR). Co-treatment of 24SOHC with 9-cis retinoic acid, a retinoid X receptor ligand, enhanced the adaptive responses. Knockdown of LXRβ by siRNA diminished the adaptive responses induced by 24SOHC almost completely. The treatment with 24SOHC induced the expression of LXR target genes, such as ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1). The 24SOHC-induced adaptive responses were significantly attenuated by siRNA for ABCG1 but not by siRNA for ABCA1. Taken together, these results strongly suggest that 24SOHC at sub-lethal concentrations induces adaptive responses via transcriptional activation of LXR signaling pathway, thereby protecting neuronal cells from subsequent 7KC-induced cytotoxicity. 24SOHC induces adaptive responses against 7KC-induced cell death in neuronal cells. Co-treatment of 24SOHC with 9cRA, an RXR ligand enhances adaptive responses. Knockdown of LXRβ suppresses 24SOHC-induced adaptive responses. ABCG1 is involved in LXR-mediated adaptive responses by 24SOHC.
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Key Words
- 24S-hydroxycholesterol
- 24SOHC, 24S-hydroxycholesterol
- 7-ketocholesterol
- 7KC, 7-ketocholesterol
- 9cRA, 9-cis retinoic acid
- ABCA1, ATP-binding cassette transporter A1
- ABCG1, ATP-binding cassette transporter G1
- AD, Alzheimer's disease
- ATP-binding cassette transporter G1
- Adaptive responses
- CYP46A1, cholesterol 24-hydroxylase
- Cell death
- FITC, fluorescein isothiocyanate
- HDL, high-density lipoprotein
- LDH, lactate dehydrogenase
- LXR, liver X receptor
- Liver X receptor
- MAP2, microtubule-associated protein 2
- MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- NC, negative control
- PI, propidium iodide
- RXR, retinoid X receptor
- atRA, all-trans retinoic acid
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Role of the circadian clock gene Per2 in adaptation to cold temperature. Mol Metab 2013; 2:184-93. [PMID: 24049733 DOI: 10.1016/j.molmet.2013.05.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 01/12/2023] Open
Abstract
Adaptive thermogenesis allows mammals to resist to cold. For instance, in brown adipose tissue (BAT) the facultative uncoupling of the proton gradient from ATP synthesis in mitochondria is used to generate systemic heat. However, this system necessitates an increase of the Uncoupling protein 1 (Ucp1) and its activation by free fatty acids. Here we show that mice without functional Period2 (Per2) were cold sensitive because their adaptive thermogenesis system was less efficient. Upon cold-exposure, Heat shock factor 1 (HSF1) induced Per2 in the BAT. Subsequently, PER2 as a co-activator of PPARα increased expression of Ucp1. PER2 also increased Fatty acid binding protein 3 (Fabp3), a protein important to transport free fatty acids from the plasma to mitochondria to activate UCP1. Hence, in BAT PER2 is important for the coordination of the molecular response of mice exposed to cold by synchronizing UCP1 expression and its activation.
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Key Words
- Adrβ3, beta-adrenergic receptor 3
- BAT, brown adipose tissue
- BMAL1, brain and muscle ARNT-like factor
- Brown adipose tissue
- CLOCK, circadian locomotor output cycles kaput
- ChIP, chromatin immunoprecipitation
- FABP3, fatty acid binding protein 3
- FFA, free fatty acids
- HSE, heat shock element
- HSF1, heat shock factor 1
- Humidity
- NPAS2, neuronal PAS-domain containing protein 2
- PGC-1, PPAR-coactivator -1
- PPAR, peroxisome proliferator-activated receptor
- PPRE, PPAR element
- Per2, Period2
- RXR, retinoid X receptor
- SCN, suprachiasmatic nuclei
- Season
- TAG, triglycerides
- UCP1, uncoupling protein 1
- WAT, white adipose tissue
- WT, wild-type
- ZT, zeitgeber time
- luc, luciferase
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Differential activation of catalase expression and activity by PPAR agonists: implications for astrocyte protection in anti-glioma therapy. Redox Biol 2013; 1:70-9. [PMID: 24024139 PMCID: PMC3757675 DOI: 10.1016/j.redox.2012.12.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 12/13/2022] Open
Abstract
Glioma survival is dismal, in part, due to an imbalance in antioxidant expression and activity. Peroxisome proliferator-activated receptor (PPAR) agonists have antineoplastic properties which present new redox-dependent targets for glioma anticancer therapies. Herein, we demonstrate that treatment of primary cultures of normal rat astrocytes with PPAR agonists increased the expression of catalase mRNA protein, and enzymatic activity. In contrast, these same agonists had no effect on catalase expression and activity in malignant rat glioma cells. The increase in steady-state catalase mRNA observed in normal rat astrocytes was due, in part, to de novo mRNA synthesis as opposed to increased catalase mRNA stability. Moreover, pioglitazone-mediated induction of catalase activity in normal rat astrocytes was completely blocked by transfection with a PPARγ-dominant negative plasmid. These data suggest that defects in PPAR-mediated signaling and gene expression may represent a block to normal catalase expression and induction in malignant glioma. The ability of PPAR agonists to differentially increase catalase expression and activity in normal astrocytes but not glioma cells suggests that these compounds might represent novel adjuvant therapeutic agents for the treatment of gliomas.
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Key Words
- 9cRA, 9 cis retinoic acid
- ActD, actinomycin D
- BCNU, 1,3-bis (2-chloroethyl)-1-nitrosourea
- C6 glioma cells
- CNS, central nervous system
- Catalase
- DCF, dichlorofluorescein
- GPx, glutathione peroxidase
- GSH, glutathione
- PPAR agonists
- PPAR, Peroxisome proliferator-activated receptor
- PPARγ-d.n, PPARγ-dominant negative
- PPARγ-dominant negative
- PPRE, PPAR-response elements
- PUFAs, polyunsaturated fatty acids
- Pio, Pioglitazone
- Primary rat astrocytes
- ROS, reactive oxygen species
- RXR, retinoid X receptor
- Rosi, Rosiglitazone
- SOD, superoxide dismutase
- TZDs, thiazolidinediones
- Transfection
- shRNA, short hairpin RNA
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