1
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Ohno R, Mainka M, Kirchhoff R, Hartung NM, Schebb NH. Sterol Derivatives Specifically Increase Anti-Inflammatory Oxylipin Formation in M2-like Macrophages by LXR-Mediated Induction of 15-LOX. Molecules 2024; 29:1745. [PMID: 38675565 PMCID: PMC11052137 DOI: 10.3390/molecules29081745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/29/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024] Open
Abstract
The understanding of the role of LXR in the regulation of macrophages during inflammation is emerging. Here, we show that LXR agonist T09 specifically increases 15-LOX abundance in primary human M2 macrophages. In time- and dose-dependent incubations with T09, an increase of 3-fold for ALOX15 and up to 15-fold for 15-LOX-derived oxylipins was observed. In addition, LXR activation has no or moderate effects on the abundance of macrophage marker proteins such as TLR2, TLR4, PPARγ, and IL-1RII, as well as surface markers (CD14, CD86, and CD163). Stimulation of M2-like macrophages with FXR and RXR agonists leads to moderate ALOX15 induction, probably due to side activity on LXR. Finally, desmosterol, 24(S),25-Ep cholesterol and 22(R)-OH cholesterol were identified as potent endogenous LXR ligands leading to an ALOX15 induction. LXR-mediated ALOX15 regulation is a new link between the two lipid mediator classes sterols, and oxylipins, possibly being an important tool in inflammatory regulation through anti-inflammatory oxylipins.
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Affiliation(s)
| | | | | | | | - Nils Helge Schebb
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaußstr. 20, 42119 Wuppertal, Germany
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2
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Alnaaim SA, Al-Kuraishy HM, Alexiou A, Papadakis M, Saad HM, Batiha GES. Role of Brain Liver X Receptor in Parkinson's Disease: Hidden Treasure and Emerging Opportunities. Mol Neurobiol 2024; 61:341-357. [PMID: 37606719 PMCID: PMC10791998 DOI: 10.1007/s12035-023-03561-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 08/01/2023] [Indexed: 08/23/2023]
Abstract
Parkinson's disease (PD) is a neurodegenerative disease due to the degeneration of dopaminergic neurons (DNs) in the substantia nigra (SN). The liver X receptor (LXR) is involved in different neurodegenerative diseases. Therefore, the objective of the present review was to clarify the possible role of LXR in PD neuropathology. LXRs are the most common nuclear receptors of transcription factors that regulate cholesterol metabolism and have pleiotropic effects, including anti-inflammatory effects and reducing intracellular cholesterol accumulation. LXRs are highly expressed in the adult brain and act as endogenous sensors for intracellular cholesterol. LXRs have neuroprotective effects against the development of neuroinflammation in different neurodegenerative diseases by inhibiting the expression of pro-inflammatory cytokines. LXRs play an essential role in mitigating PD neuropathology by reducing the expression of inflammatory signaling pathways, neuroinflammation, oxidative stress, mitochondrial dysfunction, and enhancement of BDNF signaling.In conclusion, LXRs, through regulating brain cholesterol homeostasis, may be effectual in PD. Also, inhibition of node-like receptor pyrin 3 (NLRP3) inflammasome and nuclear factor kappa B (NF-κB) by LXRs could effectively prevent neuroinflammation in PD. Taken together, LXRs play a crucial role in PD neuropathology by inhibiting neuroinflammation and associated degeneration of DNs.
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Affiliation(s)
- Saud A Alnaaim
- Clinical Neurosciences Department, College of Medicine, King Faisal University, Hofuf, Saudi Arabia
| | - Hayder M Al-Kuraishy
- Department of Clinical Pharmacology and Therapeutic Medicine, College of Medicine, ALmustansiriyiah University, Baghdad, 14132, Iraq
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, 1030, Wien, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, Heusnerstrasse 40, University of Witten-Herdecke, 42283, Wuppertal, Germany.
| | - Hebatallah M Saad
- Department of Pathology, Faculty of Veterinary Medicine, Matrouh University, Marsa Matruh, 51744, Egypt
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt
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3
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Shen X, Li Q, Hu W, Yang M, An W, Hu J. Relationships of Liver X Receptor Antagonists and Atherosclerosis in Drinking Water from Six Chinese Major Cities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19374-19382. [PMID: 37948298 DOI: 10.1021/acs.est.3c06029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
While environmental factors have been considered contributors to atherosclerosis, it remains unclear whether drinking water promotes foam cell formation, the initial event of atherosclerosis. This study revealed that drinking water from six major cities in China, namely, Harbin, Jinan, Shanghai, Wuhan, Chongqing, and Zhuhai, significantly promoted foam cell formation in an in vitro macrophage model at a minimum concentration fold of 2. Moreover, cholesterol efflux was significantly impeded by all samples at 2-16-fold, while cholesterol influx was induced only by samples from Jinan and Chongqing at 16-fold, suggesting the dominant role of efflux in foam cell formation. Interestingly, except for the sample from Jinan, the samples exhibited complete inhibition of liver X receptor α (LXRα) activities at 160-fold, indicating the potential role of chemicals in drinking water in promoting foam cell formation by antagonizing LXRα. Through LXRα protein affinity selection-mass spectrometry, we identified ten LXRα-binding compounds, with efavirenz being revealed for the first time as a significant inducer of foam cell formation through LXRα antagonism. Overall, this study clarifies the atherosclerotic risks posed by drinking water and demonstrates the efavirenz-related atherosclerotic effects.
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Affiliation(s)
- Xinming Shen
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Qiang Li
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Wenxin Hu
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Min Yang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wei An
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jianying Hu
- MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, People's Republic of China
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4
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Song YJ, Zhang J, Xu Z, Nie P, Chang MX. Liver X Receptor LXRα Promotes Grass Carp Reovirus Infection by Attenuating IRF3-CBP Interaction and Inhibiting RLR Antiviral Signaling. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:1006-1019. [PMID: 37548504 DOI: 10.4049/jimmunol.2300214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 07/05/2023] [Indexed: 08/08/2023]
Abstract
Liver X receptors (LXRs) are nuclear receptors involved in metabolism and the immune response. Different from mammalian LXRs, which include two isoforms, LXRα and LXRβ, only a single LXRα gene exists in the piscine genomes. Although a study has suggested that piscine LXR inhibits intracellular bacterial survival, the functions of piscine LXRα in viral infection are unknown. In this study, we show that overexpression of LXRα from grass carp (Ctenopharyngodon idellus), which is named as gcLXRα, increases host susceptibility to grass carp reovirus (GCRV) infection, whereas gcLXRα knockdown in CIK (C. idellus kidney) cells inhibits GCRV infection. Consistent with these functional studies, gcLXRα knockdown promotes the transcription of antiviral genes involved in the RIG-I-like receptor (RLR) antiviral signaling pathway, including IFN regulatory factor (IRF3) and the type I IFN IFN1. Further results show that gcLXRα knockdown induces the expression of CREB-binding protein (CBP), a transcriptional coactivator. In the knockdown of CBP, the inhibitory effect of gcLXRα knockdown in limiting GCRV infection is completely abolished. gcLXRα also interacts with IRF3 and CBP, which impairs the formation of the IRF3/CBP transcription complex. Moreover, gcLXRα heterodimerizes with RXRg, which cooperatively impair the transcription of the RLR antiviral signaling pathway and promote GCRV infection. Taken together, to our knowledge, our findings provide new insight into the functional correlation between nuclear receptor LXRα and the RLR antiviral signaling pathway, and they demonstrate that gcLXRα can impair the RLR antiviral signaling pathway and the production of type I IFN via forming gcLXRα/RXRg complexes and attenuating IRF3/CBP complexes.
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Affiliation(s)
- Yun Jie Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jie Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhen Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Pin Nie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Ming Xian Chang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
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5
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Thiel W, Esposito EJ, Findley AP, Blume ZI, Mitchell DM. Modulation of retinoid-X-receptors differentially regulates expression of apolipoprotein genes apoc1 and apoeb by zebrafish microglia. Biol Open 2021; 11:273656. [PMID: 34878094 PMCID: PMC8822359 DOI: 10.1242/bio.058990] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/30/2021] [Indexed: 11/20/2022] Open
Abstract
Transcriptome analyses performed in both human and zebrafish indicate strong expression of Apoe and Apoc1 by microglia. Apoe expression by microglia is well appreciated, but Apoc1 expression has not been well-examined. PPAR/RXR and LXR/RXR receptors appear to regulate expression of the apolipoprotein gene cluster in macrophages, but a similar role in microglia in vivo has not been studied. Here, we characterized microglial expression of apoc1 in the zebrafish central nervous system (CNS) in situ and demonstrate that in the CNS, apoc1 expression is unique to microglia. We then examined the effects of PPAR/RXR and LXR/RXR modulation on microglial expression of apoc1 and apoeb during early CNS development using a pharmacological approach. Changes in apoc1 and apoeb transcripts in response to pharmacological modulation were quantified by RT-qPCR in whole heads, and in individual microglia using hybridization chain reaction (HCR) in situ hybridization. We found that expression of apoc1 and apoeb by microglia were differentially regulated by LXR/RXR and PPAR/RXR modulating compounds, respectively, during development. Our results also suggest RXR receptors could be involved in endogenous induction of apoc1 expression by microglia. Collectively, our work supports the use of zebrafish to better understand regulation and function of these apolipoproteins in the CNS. Summary: Here we investigate expression of two apolipoprotein genes by microglia in the zebrafish model during normal development, and in contexts of pharmacological manipulations that target candidate regulatory receptors.
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Affiliation(s)
- Whitney Thiel
- Biological Sciences, University of Idaho, Moscow, ID 83844, Russia
| | - Emma J Esposito
- Biological Sciences, University of Idaho, Moscow, ID 83844, Russia
| | - Anna P Findley
- Biological Sciences, University of Idaho, Moscow, ID 83844, Russia
| | - Zachary I Blume
- Biological Sciences, University of Idaho, Moscow, ID 83844, Russia
| | - Diana M Mitchell
- Biological Sciences, University of Idaho, Moscow, ID 83844, Russia
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6
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Li S, Wang C, Wu Z. Dietary L-arginine supplementation of tilapia (Oreochromis niloticus) alters the microbial population and activates intestinal fatty acid oxidation. Amino Acids 2021; 54:339-351. [PMID: 34212252 DOI: 10.1007/s00726-021-03018-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 06/08/2021] [Indexed: 12/15/2022]
Abstract
Currently, little is known about the function of L-arginine in the homeostasis of intestinal lipid metabolism. This study was conducted to test the hypothesis that dietary L-arginine supplementation may alter intestinal microbiota and lipid metabolism in tilapia. Tilapia were fed a basal diet (containing 16.9 g L-arginine per kilogram diets) or the basal diet supplemented with 1% or 2% L-arginine for 8 wks. In the present study, we found that dietary supplementation with 1% or 2% L-arginine induced a shift in the community structure of gut microbiota, as showed by increased (p < 0.05) α-diversity, altered (p < 0.05) β-diversity and function profile. This finding coincided with decreased lipid accretion in the intestine of tilapia, which was associated with an enhancement in mRNA levels for peroxisome proliferator-activated receptor α (Pparα), acyl-coenzyme a oxidase 1 (Acox1), and peroxisome proliferator-activated receptor γ coactivator-1α (Pgc-1α). Using intestinal epithelial cell culture, we demonstrated that the lipid-lowering effect of L-arginine was mainly mediated by activating the AMP-activated protein kinase (AMPK) signaling pathway, carnitine palmitoyltransferase 1 (CPT1), and PPARα, as well as mRNA levels for Acox1 and Acox2. Collectively, our results suggest that dietary L-arginine supplementation of tilapia changed the intestinal microbiota and activated intestinal fatty acid oxidation. However, future studies are warranted to determine the relationship between microbiota and lipid metabolism in the intestine.
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Affiliation(s)
- Senlin Li
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, 100193, China
| | - Chao Wang
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, 100193, China. .,Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, 100193, China.
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7
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Fanti F, Merola C, Vremere A, Oliva E, Perugini M, Amorena M, Compagnone D, Sergi M. Quantitative analysis of oxysterols in zebrafish embryos by HPLC-MS/MS. Talanta 2020; 220:121393. [DOI: 10.1016/j.talanta.2020.121393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/04/2023]
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8
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Grandchamp A, Piégu B, Monget P. Genes Encoding Teleost Fish Ligands and Associated Receptors Remained in Duplicate More Frequently than the Rest of the Genome. Genome Biol Evol 2019; 11:1451-1462. [PMID: 31087101 PMCID: PMC6540934 DOI: 10.1093/gbe/evz078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2019] [Indexed: 12/15/2022] Open
Abstract
Signaling through ligand/receptor interactions is a widespread mechanism across all living taxa. During evolution, however, there has been a diversification in multigene families and changes in their interaction patterns. Among the events that led to the creation of new genes is the whole-genome duplication, which made possible some major innovations. Teleost fishes descended from a common ancestor which underwent one such whole-genome duplication. In our study, we investigated the effect of complete genome duplication on the evolution of ligand–receptor pairs in teleosts. We selected ten teleost species and used bioinformatics programs and phylogenetic tools in order to study the evolution of the human ligands and receptors that have orthologous genes in fishes, as well as the rest of the fish genomes. We established that since the complete duplication of the fish genomes, the conservation in duplicate copy of ligand and receptor genes is higher than expected. However, the ligand/receptor pair partners did not necessarily evolve in the same way, and a lot of situations occurred in which one of the partners returned in singleton copy when the other one was maintained in duplicate. This suggests that changes in interaction partners may have taken place during the evolution of teleosts. Moreover, the fate of the ligands and receptor coding genes is partly congruent with the phylogeny of teleosts. However, some incongruences can be observed. We suggest that these incongruences are correlated to the environment.
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Affiliation(s)
- Anna Grandchamp
- PRC, UMR85, INRA, CNRS, IFCE, Université de Tours, Nouzilly, France
| | - Benoît Piégu
- PRC, UMR85, INRA, CNRS, IFCE, Université de Tours, Nouzilly, France
| | - Philippe Monget
- PRC, UMR85, INRA, CNRS, IFCE, Université de Tours, Nouzilly, France
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9
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Jamadagni P, Patten SA. 25-hydroxycholesterol impairs neuronal and muscular development in zebrafish. Neurotoxicology 2019; 75:14-23. [PMID: 31449834 DOI: 10.1016/j.neuro.2019.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 08/16/2019] [Accepted: 08/16/2019] [Indexed: 12/12/2022]
Abstract
Oxysterols have essential effects on brain homeostasis and their levels are often altered in neurodegenerative and neuroinflammatory diseases. Several studies have demonstrated the cytotoxic effects of 25-HC on different cell lines, however, not much is known about its effects on neurons in vivo. In this study, we examined the effects of 25-HC exposure on the nervous system development in the zebrafish. We showed that survival rate of zebrafish embryos/larvae is significantly decreased at doses of 25-HC above 40 μM. 25-HC was found to affect the motility of zebrafish larvae, primary motor axon and muscle morphology. Furthermore, larvae treated with 25-HC showed a reduced neuronal network and number of HuC-positive cells in the brain. An increased cell death was also observed in both the brain and spinal cord of zebrafish treated with 25-HC. Interestingly, administration of 25-HC at later stages of development (24 and 48 h post fertilization) had no detrimental effects on motor axons. Altogether, our findings show that elevated levels of 25-HC may have important consequences on neuronal development and cell survival.
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Affiliation(s)
| | - Shunmoogum A Patten
- INRS Institut Armand-Frappier, Laval, QC, Canada; Centre d'Excellence en Recherche sur les Maladies Orphelines - Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montréal, QC, Canada.
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10
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Gomes IDL, Gazo I, Besnardeau L, Hebras C, McDougall A, Dumollard R. Potential roles of nuclear receptors in mediating neurodevelopmental toxicity of known endocrine-disrupting chemicals in ascidian embryos. Mol Reprod Dev 2019; 86:1333-1347. [PMID: 31215734 DOI: 10.1002/mrd.23219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 05/15/2019] [Accepted: 05/20/2019] [Indexed: 12/17/2022]
Abstract
Endocrine Disrupting Chemicals (EDCs) are molecules able to interfere with the vertebrate hormonal system in different ways, a major one being the modification of the activity of nuclear receptors (NRs). Several NRs are expressed in the vertebrate brain during embryonic development and these NRs are suspected to be responsible for the neurodevelopmental defects induced by exposure to EDCs in fishes or amphibians and to participate in several neurodevelopmental disorders observed in humans. Known EDCs exert toxicity not only on vertebrate forms of marine life but also on marine invertebrates. However, because hormonal systems of invertebrates are poorly understood, it is not clear whether the teratogenic effects of known EDCs are because of endocrine disruption. The most conserved actors of endocrine systems are the NRs which are present in all metazoan genomes but their functions in invertebrate organisms are still insufficiently characterized. EDCs like bisphenol A have recently been shown to affect neurodevelopment in marine invertebrate chordates called ascidians. Because such phenotypes can be mediated by NRs expressed in the ascidian embryo, we review all the information available about NRs expression during ascidian embryogenesis and discuss their possible involvement in the neurodevelopmental phenotypes induced by EDCs.
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Affiliation(s)
- Isa D L Gomes
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Ievgeniia Gazo
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Lydia Besnardeau
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Céline Hebras
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Alex McDougall
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
| | - Rémi Dumollard
- Sorbonne Université/CNRS, Institut de la Mer, UMR7009 Laboratoire de Biologie du Développement, 06230, Villefranche-sur-Mer, France
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Khieokhajonkhet A, Aeksiri N, Kaneko G. Molecular characterization and homology modeling of liver X receptor in Asian seabass, Lates calcarifer: predicted functions in reproduction and lipid metabolism. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:523-538. [PMID: 30806874 DOI: 10.1007/s10695-019-00617-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 02/06/2019] [Indexed: 06/09/2023]
Abstract
Liver X receptor (LXR) is a ligand-activated transcription factor that plays vital roles in maintaining cholesterol and lipid homeostasis. Much work has been done on mammalian LXRs, but the role of LXR in fish remains unclear. In the present study, LXR gene was identified from adult Asian seabass, Lates calcarifer, and its predicted protein structure was docked with several cholesterol derivatives at the binding site. The LXR cDNA consisted of 1495 bp encoding a putative LXR protein of 494 amino acids. The Asian seabass LXR retained many important structural features found in LXRs of other fishes and mammals, such as putative signal peptide, activation function-1 (AF-1) domain, DNA-binding domain (DBD), ligand-binding domain (LBD), activation function-2 (AF-2) domain, and eight conserved cysteine residues. The deduced amino acid sequence of LXR shared significant identity with those of other species ranging from 65.7 to 95.8%. The homology modeling and in silico molecular docking demonstrated that Asian seabass LXR could interact with cholesterol derivatives at amino acid residues Phe274 and Ile312. Real-time PCR further revealed that LXR transcripts are ubiquitously expressed in all tissues examined, with the highest levels detected in the gonad followed by the liver. Given the well-known importance of cholesterol-mediated signaling in these tissues, Asian seabass LXR may reasonably be involved in reproduction and lipid metabolism.
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Affiliation(s)
- Anurak Khieokhajonkhet
- Center for Agriculture Biotechnology, Faculty of Agriculture, Natural Resources, and Environment, Naresuan University, Phitsanulok, 65000, Thailand.
- Department of Agricultural Sciences, Faculty of Agriculture, Natural Resources, and Environment, Naresuan University, 99 M. 1, T. Thapo, A. Muang, Phitsanulok, 65000, Thailand.
| | - Niran Aeksiri
- Center for Agriculture Biotechnology, Faculty of Agriculture, Natural Resources, and Environment, Naresuan University, Phitsanulok, 65000, Thailand
- Department of Agricultural Sciences, Faculty of Agriculture, Natural Resources, and Environment, Naresuan University, 99 M. 1, T. Thapo, A. Muang, Phitsanulok, 65000, Thailand
| | - Gen Kaneko
- School of Arts and Sciences, University of Houston-Victoria, 3007 N. Ben Wilson, Victoria, TX, 77901, USA
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Rannug A, Rannug U. The tryptophan derivative 6-formylindolo[3,2-b]carbazole, FICZ, a dynamic mediator of endogenous aryl hydrocarbon receptor signaling, balances cell growth and differentiation. Crit Rev Toxicol 2018; 48:555-574. [PMID: 30226107 DOI: 10.1080/10408444.2018.1493086] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is not essential to survival, but does act as a key regulator of many normal physiological events. The role of this receptor in toxicological processes has been studied extensively, primarily employing the high-affinity ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, regulation of physiological responses by endogenous AHR ligands remains to be elucidated. Here, we review developments in this field, with a focus on 6-formylindolo[3,2-b]carbazole (FICZ), the endogenous ligand with the highest affinity to the receptor reported to date. The binding of FICZ to different isoforms of the AHR seems to be evolutionarily well conserved and there is a feedback loop that controls AHR activity through metabolic degradation of FICZ via the highly inducible cytochrome P450 1A1. Several investigations provide strong evidence that FICZ plays a critical role in normal physiological processes and can ameliorate immune diseases with remarkable efficiency. Low levels of FICZ are pro-inflammatory, providing resistance to pathogenic bacteria, stimulating the anti-tumor functions, and promoting the differentiation of cancer cells by repressing genes in cancer stem cells. In contrast, at high concentrations FICZ behaves in a manner similar to TCDD, exhibiting toxicity toward fish and bird embryos, immune suppression, and activation of cancer progression. The findings are indicative of a dual role for endogenously activated AHR in barrier tissues, aiding clearance of infections and suppressing immunity to terminate a vicious cycle that might otherwise lead to disease. There is not much support for the AHR ligand-specific immune responses proposed, the differences between FICZ and TCDD in this context appear to be explained by the rapid metabolism of FICZ.
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Affiliation(s)
- Agneta Rannug
- a Karolinska Institutet, Institute of Environmental Medicine , Stockholm , Sweden
| | - Ulf Rannug
- b Department of Molecular Biosciences , The Wenner-Gren Institute, Stockholm University , Stockholm , Sweden
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13
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Janosik T, Rannug A, Rannug U, Wahlström N, Slätt J, Bergman J. Chemistry and Properties of Indolocarbazoles. Chem Rev 2018; 118:9058-9128. [PMID: 30191712 DOI: 10.1021/acs.chemrev.8b00186] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The indolocarbazoles are an important class of nitrogen heterocycles which has evolved significantly in recent years, with numerous studies focusing on their diverse biological effects, or targeting new materials with potential applications in organic electronics. This review aims at providing a broad survey of the chemistry and properties of indolocarbazoles from an interdisciplinary point of view, with particular emphasis on practical synthetic aspects, as well as certain topics which have not been previously accounted for in detail, such as the occurrence, formation, biological activities, and metabolism of indolo[3,2- b]carbazoles. The literature of the past decade forms the basis of the text, which is further supplemented with older key references.
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Affiliation(s)
- Tomasz Janosik
- Research Institutes of Sweden , Bioscience and Materials, RISE Surface, Process and Formulation , SE-151 36 Södertälje , Sweden
| | - Agneta Rannug
- Institute of Environmental Medicine , Karolinska Institutet , SE-171 77 Stockholm , Sweden
| | - Ulf Rannug
- Department of Molecular Biosciences, The Wenner-Gren Institute , Stockholm University , SE-106 91 Stockholm , Sweden
| | | | - Johnny Slätt
- Department of Chemistry, Applied Physical Chemistry , KTH Royal Institute of Technology , SE-100 44 Stockholm , Sweden
| | - Jan Bergman
- Karolinska Institutet , Department of Biosciences and Nutrition , SE-141 83 Huddinge , Sweden
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14
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Ayisi CL, Yamei C, Zhao JL. Genes, transcription factors and enzymes involved in lipid metabolism in fin fish. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.aggene.2017.09.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Fonseca E, Ruivo R, Lopes-Marques M, Zhang H, Santos MM, Venkatesh B, Castro LFC. LXRα and LXRβ Nuclear Receptors Evolved in the Common Ancestor of Gnathostomes. Genome Biol Evol 2017; 9:222-230. [PMID: 28057729 PMCID: PMC5381633 DOI: 10.1093/gbe/evw305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2016] [Indexed: 12/25/2022] Open
Abstract
Nuclear receptors (NRs) regulate numerous aspects of the endocrine system. They mediate endogenous and exogenous cues, ensuring a homeostatic control of development and metabolism. Gene duplication, loss and mutation have shaped the repertoire and function of NRs in metazoans. Here, we examine the evolution of a pivotal orchestrator of cholesterol metabolism in vertebrates, the liver X receptors (LXRs). Previous studies suggested that LXRα and LXRβ genes emerged in the mammalian ancestor. However, we show through genome analysis and functional assay that bona fide LXRα and LXRβ orthologues are present in reptiles, coelacanth and chondrichthyans but not in cyclostomes. These findings show that LXR duplicated before gnathostome radiation, followed by asymmetric paralogue loss in some lineages. We suggest that a tighter control of cholesterol levels in vertebrates was achieved through the exploitation of a wider range of oxysterols, an ability contingent on ligand-binding pocket remodeling.
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Affiliation(s)
- Elza Fonseca
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto, Portugal.,Department of Biology, FCUP - Faculty of Sciences, U. Porto, Portugal
| | - Raquel Ruivo
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto, Portugal
| | - Mónica Lopes-Marques
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto, Portugal.,ICBAS - Institute of Biomedical Sciences Abel Salazar - U. Porto, Portugal
| | - Huixian Zhang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Biopolis, Singapore
| | - Miguel M Santos
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto, Portugal.,Department of Biology, FCUP - Faculty of Sciences, U. Porto, Portugal
| | - Byrappa Venkatesh
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Biopolis, Singapore.,Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - L Filipe C Castro
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, U. Porto, Portugal.,Department of Biology, FCUP - Faculty of Sciences, U. Porto, Portugal
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16
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Abstract
Strigolactones (SLs) are a collection of related small molecules that act as hormones in plant growth and development. Intriguingly, SLs also act as ecological communicators between plants and mycorrhizal fungi and between host plants and a collection of parasitic plant species. In the case of mycorrhizal fungi, SLs exude into the soil from host roots to attract fungal hyphae for a beneficial interaction. In the case of parasitic plants, however, root-exuded SLs cause dormant parasitic plant seeds to germinate, thereby allowing the resulting seedling to infect the host and withdraw nutrients. Because a laboratory-friendly model does not exist for parasitic plants, researchers are currently using information gleaned from model plants like
Arabidopsis in combination with the chemical probes developed through chemical genetics to understand SL perception of parasitic plants. This work first shows that understanding SL signaling is useful in developing chemical probes that perturb SL perception. Second, it indicates that the chemical space available to probe SL signaling in both model and parasitic plants is sizeable. Because these parasitic pests represent a major concern for food insecurity in the developing world, there is great need for chemical approaches to uncover novel lead compounds that perturb parasitic plant infections.
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Affiliation(s)
- Shelley Lumba
- Cell and Systems Biology, University of Toronto, and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Michael Bunsick
- Cell and Systems Biology, University of Toronto, and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Peter McCourt
- Cell and Systems Biology, University of Toronto, and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
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17
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Benítez-Santana T, Hugo SE, Schlegel A. Role of Intestinal LXRα in Regulating Post-prandial Lipid Excursion and Diet-Induced Hypercholesterolemia and Hepatic Lipid Accumulation. Front Physiol 2017; 8:280. [PMID: 28536535 PMCID: PMC5422522 DOI: 10.3389/fphys.2017.00280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/18/2017] [Indexed: 12/12/2022] Open
Abstract
Post-prandial hyperlipidemia has emerged as a cardiovascular risk factor with limited therapeutic options. The Liver X receptors (Lxrs) are nuclear hormone receptors that regulate cholesterol elimination. Knowledge of their role in regulating the absorption and handling of dietary fats is incomplete. The purpose of this study was to determine the role of intestinal Lxrα in post-prandial intestinal lipid transport. Using Lxrα knockout (nr1h3−/−) and intestine-limited Lxrα over-expressing [Tg(fabp2a:EGFP-nr1h3)] zebrafish strains, we measured post-prandial lipid excursion with live imaging in larvae and physiological methods in adults. We also conducted a long-term high-cholesterol dietary challenge in adults to examine the chronic effect of modulating nr1h3 gene dose on the development of hypercholesterolemia and hepatic lipid accumulation. Over-expression of Lxrα in the intestine delays the transport of ingested lipids in larvae, while deletion of Lxrα increases the rate of lipid transport. Pre-treating wildtype larvae with the liver-sparing Lxr agonist hyodeoxycholic acid also delayed the rate of intestinal lipid transport in larvae. In adult males, deletion of Lxrα accelerates intestinal transport of ingested lipids. Adult females showed higher plasma Lipoprotein lipase (Lpl) activity compared to males, and lower post-gavage blood triacylglycerol (TAG) excursion. Despite the sexually dimorphic effect on acute intestinal lipid handling, Tg(fabp2a:EGFP-nr1h3) adults of both sexes are protected from high cholesterol diet (HCD)-induced hepatic lipid accumulation, while nr1h3−/− mutants are sensitive to the effects of HCD challenge. These data indicate that intestinal Lxr activity dampens the pace of intestinal lipid transport cell-autonomously. Selective activation of intestinal Lxrα holds therapeutic promise.
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Affiliation(s)
- Tibiábin Benítez-Santana
- University of Utah Molecular Medicine Program, School of Medicine, University of UtahSalt Lake City, UT, USA.,Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, School of Medicine, University of UtahSalt Lake City, UT, USA
| | - Sarah E Hugo
- University of Utah Molecular Medicine Program, School of Medicine, University of UtahSalt Lake City, UT, USA.,Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, School of Medicine, University of UtahSalt Lake City, UT, USA
| | - Amnon Schlegel
- University of Utah Molecular Medicine Program, School of Medicine, University of UtahSalt Lake City, UT, USA.,Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, School of Medicine, University of UtahSalt Lake City, UT, USA.,Department of Biochemistry, School of Medicine, University of UtahSalt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, College of Health, University of UtahSalt Lake City, UT, USA
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18
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Lumba S, Subha A, McCourt P. Found in Translation: Applying Lessons from Model Systems to Strigolactone Signaling in Parasitic Plants. Trends Biochem Sci 2017; 42:556-565. [PMID: 28495334 DOI: 10.1016/j.tibs.2017.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/05/2017] [Accepted: 04/20/2017] [Indexed: 01/14/2023]
Abstract
Strigolactones (SLs) are small molecules that act as endogenous hormones to regulate plant development as well as exogenous cues that help parasitic plants to infect their hosts. Given that parasitic plants are experimentally challenging systems, researchers are using two approaches to understand how they respond to host-derived SLs. The first involves extrapolating information on SLs from model genetic systems to dissect their roles in parasitic plants. The second uses chemicals to probe SL signaling directly in the parasite Striga hermonthica. These approaches indicate that parasitic plants have co-opted a family of α/β hydrolases to perceive SLs. The importance of this genetic and chemical information cannot be overstated since parasitic plant infestations are major obstacles to food security in the developing world.
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Affiliation(s)
- Shelley Lumba
- Cell and Systems Biology, University of Toronto and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Asrinus Subha
- Cell and Systems Biology, University of Toronto and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Peter McCourt
- Cell and Systems Biology, University of Toronto and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada.
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19
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Newmark H, Dantoft W, Ghazal P. Evolutionary Origin of the Interferon-Immune Metabolic Axis: The Sterol-Vitamin D Link. Front Immunol 2017; 8:62. [PMID: 28232830 PMCID: PMC5298971 DOI: 10.3389/fimmu.2017.00062] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/16/2017] [Indexed: 12/24/2022] Open
Abstract
In vertebrate animals, the sterol metabolic network is emerging as a central player in immunity and inflammation. Upon infection, flux in the network is acutely moderated by the interferon (IFN) response through direct molecular and bi-directional communications. How sterol metabolism became linked to IFN control and for what purpose is not obvious. Here, we deliberate on the origins of these connections based on a systematic review of the literature. A narrative synthesis of publications that met eligibility criteria allowed us to trace an evolutionary path and functional connections between cholesterol metabolism and immunity. The synthesis supports an ancestral link between toxic levels of cholesterol-like products and the vitamin D receptor (VDR). VDR is an ancient nuclear hormone receptor that was originally involved in the recognition and detoxification of xenobiotic marine biotoxins exhibiting planar sterol ring scaffolds present in aquatic environments. Coadaptation of this receptor with the acquisition of sterol biosynthesis and IFNs in vertebrate animals set a stage for repurposing and linking a preexisting host-protection mechanism of harmful xenobiotics to become an important regulator in three key interlinked biological processes: bone development, immunity, and calcium homeostasis. We put forward the hypothesis that sterol metabolites, especially oxysterols, have acted as evolutionary drivers in immunity and may represent the first example of small-molecule metabolites linked to the adaptive coevolution and diversification of host metabolic and immune regulatory pathways.
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Affiliation(s)
- Harry Newmark
- Division of Infection and Pathway Medicine, School of Biomedical Sciences, University of Edinburgh , Edinburgh , UK
| | - Widad Dantoft
- Division of Infection and Pathway Medicine, School of Biomedical Sciences, University of Edinburgh , Edinburgh , UK
| | - Peter Ghazal
- Division of Infection and Pathway Medicine, School of Biomedical Sciences, University of Edinburgh , Edinburgh , UK
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20
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Chen Q, Chen J, Chen J, Lu XJ. Molecular and functional characterization of liver X receptor in ayu, Plecoglossus altivelis: Regulator of inflammation and efferocytosis. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 65:358-368. [PMID: 27539204 DOI: 10.1016/j.dci.2016.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/14/2016] [Accepted: 08/14/2016] [Indexed: 06/06/2023]
Abstract
Liver X receptors (LXR) are modulators of metabolic processes and inflammation in mammals as nuclear receptors. However, the precise function of LXR in teleosts remains unclear. Here, we characterized a LXR gene (PaLXR) from ayu, Plecoglossus altivelis. The PaLXR transcript was expressed widely in all tissues studied, and changes in expression were observed in tissues and monocytes/macrophages (MO/MΦ) upon infection with the bacterium Edwardsiella ictaluri. PaLXR activation decreased the mRNA expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-10 upon E. ictaluri infection, while their expression was increased following the knockdown of PaLXR by siRNA. Moreover, E. ictaluri infection induced the apoptosis of ayu neutrophils and PaLXR activation enhanced the internalization of E. ictaluri-infected apoptotic neutrophils by MO/MΦ (efferocytosis), while PaLXR knockdown led to decreased efferocytosis. Furthermore, PaLXR activation inhibited intracellular bacterial survival during efferocytosis, while PaLXR knockdown enhanced survival. In conclusion, our results indicate that PaLXR plays a role in the modulation of innate immune responses in ayu MO/MФ.
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Affiliation(s)
- Qiang Chen
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China; The Donghai Sea Collaborative Innovation Center for Industrial Upgrading Mariculture, Ningbo University, Ningbo 315211, China
| | - Jie Chen
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China; The Donghai Sea Collaborative Innovation Center for Industrial Upgrading Mariculture, Ningbo University, Ningbo 315211, China
| | - Jiong Chen
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China; The Donghai Sea Collaborative Innovation Center for Industrial Upgrading Mariculture, Ningbo University, Ningbo 315211, China.
| | - Xin-Jiang Lu
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China.
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21
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O’Meara MJ, Ballouz S, Shoichet BK, Gillis J. Ligand Similarity Complements Sequence, Physical Interaction, and Co-Expression for Gene Function Prediction. PLoS One 2016; 11:e0160098. [PMID: 27467773 PMCID: PMC4965129 DOI: 10.1371/journal.pone.0160098] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/13/2016] [Indexed: 12/13/2022] Open
Abstract
The expansion of protein-ligand annotation databases has enabled large-scale networking of proteins by ligand similarity. These ligand-based protein networks, which implicitly predict the ability of neighboring proteins to bind related ligands, may complement biologically-oriented gene networks, which are used to predict functional or disease relevance. To quantify the degree to which such ligand-based protein associations might complement functional genomic associations, including sequence similarity, physical protein-protein interactions, co-expression, and disease gene annotations, we calculated a network based on the Similarity Ensemble Approach (SEA: sea.docking.org), where protein neighbors reflect the similarity of their ligands. We also measured the similarity with functional genomic networks over a common set of 1,131 genes, and found that the networks had only small overlaps, which were significant only due to the large scale of the data. Consistent with the view that the networks contain different information, combining them substantially improved Molecular Function prediction within GO (from AUROC~0.63–0.75 for the individual data modalities to AUROC~0.8 in the aggregate). We investigated the boost in guilt-by-association gene function prediction when the networks are combined and describe underlying properties that can be further exploited.
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Affiliation(s)
- Matthew J. O’Meara
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, 94158–2550, United States of America
| | - Sara Ballouz
- Cold Spring Harbor Laboratory, Stanley Institute for Cognitive Genomics, 500 Sunnyside Boulevard, Woodbury, NY, 11797, United States of America
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, 94158–2550, United States of America
- * E-mail: (BKS); (JG)
| | - Jesse Gillis
- Cold Spring Harbor Laboratory, Stanley Institute for Cognitive Genomics, 500 Sunnyside Boulevard, Woodbury, NY, 11797, United States of America
- * E-mail: (BKS); (JG)
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22
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Cytochrome P450 20A1 in zebrafish: Cloning, regulation and potential involvement in hyperactivity disorders. Toxicol Appl Pharmacol 2016; 296:73-84. [PMID: 26853319 DOI: 10.1016/j.taap.2016.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/29/2016] [Accepted: 02/01/2016] [Indexed: 12/17/2022]
Abstract
Cytochrome P450 (CYP) enzymes for which there is no functional information are considered "orphan" CYPs. Previous studies showed that CYP20A1, an orphan, is expressed in human hippocampus and substantia nigra, and in zebrafish (Danio rerio) CYP20A1 maternal transcript occurs in eggs, suggesting involvement in brain and in early development. Moreover, hyperactivity is reported in humans with chromosome 2 microdeletions including CYP20A1. We examined CYP20A1 in zebrafish, including impacts of chemical exposure on expression. Zebrafish CYP20A1 cDNA was cloned, sequenced, and aligned with cloned human CYP20A1 and predicted vertebrate orthologs. CYP20A1s share a highly conserved N-terminal region and unusual sequences in the I-helix and the heme-binding CYP signature motifs. CYP20A1 mRNA expression was observed in adult zebrafish organs including the liver, heart, gonads, spleen and brain, as well as the eye and optic nerve. Putative binding sites in proximal promoter regions of CYP20A1s, and response of zebrafish CYP20A1 to selected nuclear and xenobiotic receptor agonists, point to up-regulation by agents involved in steroid hormone response, cholesterol and lipid metabolism. There also was a dose-dependent reduction of CYP20A1 expression in embryos exposed to environmentally relevant levels of methylmercury. Morpholino knockdown of CYP20A1 in developing zebrafish resulted in behavioral effects, including hyperactivity and a slowing of the optomotor response in larvae. The results suggest that altered expression of CYP20A1 might be part of a mechanism linking methylmercury exposure to neurobehavioral deficits. The expanded information on CYP20A1 brings us closer to "deorphanization", that is, identifying CYP20A1 functions and its roles in health and disease.
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23
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Ouadah-Boussouf N, Babin PJ. Pharmacological evaluation of the mechanisms involved in increased adiposity in zebrafish triggered by the environmental contaminant tributyltin. Toxicol Appl Pharmacol 2016; 294:32-42. [PMID: 26812627 DOI: 10.1016/j.taap.2016.01.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/09/2016] [Accepted: 01/09/2016] [Indexed: 01/06/2023]
Abstract
One proposed contributing factor to the rise in overweight and obesity is exposure to endocrine disrupting chemicals. Tributyltin chloride (TBT), an organotin, induces adipogenesis in cell culture models and may increases adipose mass in vivo in vertebrate model organisms. It has been hypothesized that TBT acts via the peroxisome proliferator activated receptor (PPAR)γ-dependent pathway. However, the mechanisms involved in the effects of TBT exposure on in vivo adipose tissue metabolism remain unexplored. Semitransparent zebrafish larvae, with their well-developed white adipose tissue, offer a unique opportunity for studying the effects of toxicant chemicals and pharmaceuticals on adipocyte biology and whole-organism adiposity in a vertebrate model. Within hours, zebrafish larvae, treated at environmentally-relevant nanomolar concentrations of TBT, exhibited a remarkable increase in adiposity linked to adipocyte hypertrophy. Under the experimental conditions used, we also demonstrated that zebrafish larvae adipose tissue proved to be highly responsive to selected human nuclear receptor agonists and antagonists. Retinoid X receptor (RXR) homodimers and RXR/liver X receptor heterodimers were suggested to be in vivo effectors of the obesogenic effect of TBT on zebrafish white adipose tissue. RXR/PPARγ heterodimers may be recruited to modulate adiposity in zebrafish but were not a necessary requirement for the short term in vivo TBT obesogenic effect. Together, the present results suggest that TBT may induce the promotion of triacylglycerol storage in adipocytes via RXR-dependent pathways without necessary using PPAR isoforms.
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Affiliation(s)
- Nafia Ouadah-Boussouf
- Maladies Rares: Génétique et Métabolisme (MRGM), Univ. Bordeaux, INSERM, U1211, F-33615 Pessac, France
| | - Patrick J Babin
- Maladies Rares: Génétique et Métabolisme (MRGM), Univ. Bordeaux, INSERM, U1211, F-33615 Pessac, France.
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24
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Pan YX, Luo Z, Zhuo MQ, Hu W, Wu K, Shi X, Xu YH. Liver X Receptor (LXR) in yellow catfish Pelteobagrus fulvidraco: Molecular characterization, mRNA tissue expression and transcriptional regulation by insulin in vivo and in vitro. Comp Biochem Physiol B Biochem Mol Biol 2016; 191:13-9. [DOI: 10.1016/j.cbpb.2015.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 08/08/2015] [Accepted: 08/26/2015] [Indexed: 01/08/2023]
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25
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Esser C, Rannug A. The aryl hydrocarbon receptor in barrier organ physiology, immunology, and toxicology. Pharmacol Rev 2015; 67:259-79. [PMID: 25657351 DOI: 10.1124/pr.114.009001] [Citation(s) in RCA: 351] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is an evolutionarily old transcription factor belonging to the Per-ARNT-Sim-basic helix-loop-helix protein family. AhR translocates into the nucleus upon binding of various small molecules into the pocket of its single-ligand binding domain. AhR binding to both xenobiotic and endogenous ligands results in highly cell-specific transcriptome changes and in changes in cellular functions. We discuss here the role of AhR for immune cells of the barrier organs: skin, gut, and lung. Both adaptive and innate immune cells require AhR signaling at critical checkpoints. We also discuss the current two prevailing views-namely, 1) AhR as a promiscuous sensor for small chemicals and 2) a role for AhR as a balancing factor for cell differentiation and function, which is controlled by levels of endogenous high-affinity ligands. AhR signaling is considered a promising drug and preventive target, particularly for cancer, inflammatory, and autoimmune diseases. Therefore, understanding its biology is of great importance.
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Affiliation(s)
- Charlotte Esser
- Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany (C.E.); and Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden (A.R.)
| | - Agneta Rannug
- Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany (C.E.); and Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden (A.R.)
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26
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Cheng YY, Tao WJ, Chen JL, Sun LN, Zhou LY, Song Q, Wang DS. Genome-wide identification, evolution and expression analysis of nuclear receptor superfamily in Nile tilapia, Oreochromis niloticus. Gene 2015; 569:141-52. [PMID: 26024593 DOI: 10.1016/j.gene.2015.05.057] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/22/2015] [Accepted: 05/22/2015] [Indexed: 01/19/2023]
Abstract
The nuclear receptor (NR) superfamily, which is divided into 7 subfamilies, constitutes one of the largest classes of transcription factors. In this study, through comprehensive database search, we identified all NRs (including 4 novel members) from the tilapia (75), common carp (137), zebrafish (73), fugu (73), tetraodon (72), stickleback (70), medaka (69), coelacanth (55), spotted gar (51) and elephant shark (50). For 21 NRs, two duplicates were found in teleosts, while only one in tetrapods. These duplicates, except those of DAX1, SHP and GCNF found in the elephant shark, were derived from 3R (third round of genome duplication). The linkage duplication of 5 syntenic blocks (comprising 14 duplicated NR couples) in teleosts further supported their 3R origin. Based on transcriptome data from adult tilapia, 53 NRs were found to be expressed in more than one tissue (brain, head kidney, heart, liver, kidney, muscle, ovary and testis), and 4 were tissue-specific, indicating their essential roles in the corresponding tissue. Based on the XX and XY gonadal transcriptome data from four developmental stages, 65 NRs were detected in gonads, with 21, 31, 11 and 29 expressed sexual dimorphically at 5, 30, 90 and 180days after hatching, respectively. The expression of four selected genes was examined by in situ hybridization (ISH) and quantitative PCR (qPCR) to validate the spatial and temporal expression profiles of NRs. Comparative analyses of the expression profiles of duplicated NRs revealed divergence in gene expression as well as gene function. Our results demonstrated that NRs may play important roles in sex determination and gonadal development in teleosts.
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Affiliation(s)
- Yun-Ying Cheng
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China
| | - Wen-Jing Tao
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China
| | - Jin-Lin Chen
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China
| | - Li-Na Sun
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China
| | - Lin-Yan Zhou
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China
| | - Qiang Song
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China
| | - De-Shou Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, 400715, Chongqing, PR China.
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27
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Tompsett AR, Higley E, Pryce S, Giesy JP, Hecker M, Wiseman S. Transcriptional changes in African clawed frogs (Xenopus laevis) exposed to 17α-ethynylestradiol during early development. ECOTOXICOLOGY (LONDON, ENGLAND) 2015; 24:321-329. [PMID: 25427717 DOI: 10.1007/s10646-014-1380-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/02/2014] [Indexed: 06/04/2023]
Abstract
Although the past two decades have witnessed a significant increase in the number of studies investigating effects of estrogenic chemicals on amphibians, to date little is known about specific molecular interactions of estrogens with the hypothalamus-pituitary-gonadal-hepatic axis in developing amphibians. Here, tissue-specific functional sets of genes, derived previously from studies of fishes exposed to endocrine active chemicals, were evaluated in Xenopus laevis exposed to 17α-ethynylestradiol (EE2) throughout their early development. Specifically, transcriptional responses of X. laevis exposed to 0.09, 0.84, or 8.81 µg EE2/L were characterized during sexual differentiation [31 day post hatch (dph)] and after completion of metamorphosis during the juvenile stage (89 dph). While at 31 dph there were no consistent effects of EE2 on abundances of transcripts,at 89 dph X. laevis exhibited significant alterations in expression of genes involved in steroid signaling and metabolism, synthesis of cholesterol, and vitellogenesis. Specifically, expression of androgen receptor, farnesyl diphosphate synthase, estrogen receptor α, and vitellogenin A2 was significantly greater (>2-fold) than in controls while expression of farnesoid x-activated receptors α and β was significantly less (>2-fold reduction) than in controls. These results support the hypothesis that sets of genes derived from studies in teleost fish can be extrapolated for use in amphibians during the juvenile stage but not in sexually undifferentiated individuals. Furthermore, changes in abundances of transcripts of the here utilized sets of genes in animals sampled post sexual differentiation were in accordance with developmental effects and alterations of gonadal histology reported in a parallel study. This set of genes might be useful for predicting potential adverse outcomes at later life-stages.
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Affiliation(s)
- Amber R Tompsett
- Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, S7N 5B3, Canada
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Ma AZS, Song ZY, Zhang Q. Cholesterol efflux is LXRα isoform-dependent in human macrophages. BMC Cardiovasc Disord 2014; 14:80. [PMID: 24996838 PMCID: PMC4107624 DOI: 10.1186/1471-2261-14-80] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 06/26/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The nuclear receptor liver X receptor (LXR) has two isoforms: LXRα and LXRβ. LXR activation promotes cholesterol efflux in macrophages, but the relative importance of each LXR isoform in mediating cholesterol efflux remains elusive. METHODS We evaluated the ability of different doses of LXRs agonist T0901317 to affect cholesterol efflux in human macrophages and its relationship with mRNA and protein levels of several well-characterized proteins involved in cholesterol efflux, including ABCA1, ABCG1, SR-BI, LXRβ and LXRα, using quantitative real-time PCR, Western blotting, and siRNA techniques. RESULTS Here we show that LXRα rather than LXRβ sustains baseline cholesterol efflux in human blood-derived macrophages. Treatment of human macrophages with a non-isoform-specific LXR agonist T0901317 substantially increased HDL- and apoA-I-mediated cholesterol efflux, which was associated with increased mRNA and protein expression levels of ABCA1, ABCG1, SR-BI, LXRα and LXRβ. The siRNA- mediated silencing of LXRα, but not LXRβ significantly reduced the protein levels of ABCA1,ABCG1, and SR-BI as wellas HDL- and ApoA1-mediated cholesterol in human macrophages. CONCLUSIONS These findings imply that LXRα- rather than LXRβ- specific agonists may promote reverse cholesterol transport in humans.
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Affiliation(s)
| | - Zhi Yuan Song
- Department of Cardiology, Southwest Hospital, The Third Military Medical University, Chongqing, China.
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Affiliation(s)
- Pengxiang Huang
- Metabolic Signaling and Disease Program, Sanford-Burnham Medical Research Institute, Orlando, FL 32827, USA
| | - Vikas Chandra
- Metabolic Signaling and Disease Program, Sanford-Burnham Medical Research Institute, Orlando, FL 32827, USA
| | - Fraydoon Rastinejad
- Metabolic Signaling and Disease Program, Sanford-Burnham Medical Research Institute, Orlando, FL 32827, USA
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Serviddio G, Blonda M, Bellanti F, Villani R, Iuliano L, Vendemiale G. Oxysterols and redox signaling in the pathogenesis of non-alcoholic fatty liver disease. Free Radic Res 2013; 47:881-93. [PMID: 24000796 DOI: 10.3109/10715762.2013.835048] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Oxysterols are oxidized species of cholesterol coming from exogenous (e.g. dietary) and endogenous (in vivo) sources. They play critical roles in normal physiologic functions such as regulation of cellular cholesterol homeostasis. Most of biological effects are mediated by interaction with nuclear receptor LXRα, highly expressed in the liver as well as in many other tissues. Such interaction participates in the regulation of whole-body cholesterol metabolism, by acting as "lipid sensors". Moreover, it seems that oxysterols are also suspected to play key roles in several pathologies, including cardiovascular and inflammatory disease, cancer, and neurodegeneration. Growing evidence suggests that oxysterols may contribute to liver injury in non-alcoholic fatty liver disease. The present review focuses on the current status of knowledge on oxysterols' biological role, with an emphasis on LXR signaling and oxysterols' physiopathological relevance in NAFLD, suggesting new pharmacological development that needs to be addressed in the near future.
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Affiliation(s)
- G Serviddio
- C.U.R.E. Centre for Liver Diseases Research and Treatment, Institute of Internal Medicine, Department of Medical and Surgical Sciences, University of Foggia , Italy
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Conservation of lipid metabolic gene transcriptional regulatory networks in fish and mammals. Gene 2013; 534:1-9. [PMID: 24177230 DOI: 10.1016/j.gene.2013.10.040] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 10/01/2013] [Accepted: 10/21/2013] [Indexed: 01/04/2023]
Abstract
Lipid content and composition in aquafeeds have changed rapidly as a result of the recent drive to replace ecologically limited marine ingredients, fishmeal and fish oil (FO). Terrestrial plant products are the most economic and sustainable alternative; however, plant meals and oils are devoid of physiologically important cholesterol and long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic (EPA), docosahexaenoic (DHA) and arachidonic (ARA) acids. Although replacement of dietary FO with vegetable oil (VO) has little effect on growth in Atlantic salmon (Salmo salar), several studies have shown major effects on the activity and expression of genes involved in lipid homeostasis. In vertebrates, sterols and LC-PUFA play crucial roles in lipid metabolism by direct interaction with lipid-sensing transcription factors (TFs) and consequent regulation of target genes. The primary aim of the present study was to elucidate the role of key TFs in the transcriptional regulation of lipid metabolism in fish by transfection and overexpression of TFs. The results show that the expression of genes of LC-PUFA biosynthesis (elovl and fads2) and cholesterol metabolism (abca1) are regulated by Lxr and Srebp TFs in salmon, indicating highly conserved regulatory mechanism across vertebrates. In addition, srebp1 and srebp2 mRNA respond to replacement of dietary FO with VO. Thus, Atlantic salmon adjust lipid metabolism in response to dietary lipid composition through the transcriptional regulation of gene expression. It may be possible to further increase efficient and effective use of sustainable alternatives to marine products in aquaculture by considering these important molecular interactions when formulating diets.
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Falany CN, Rohn-Glowacki KJ. SULT2B1: unique properties and characteristics of a hydroxysteroid sulfotransferase family. Drug Metab Rev 2013; 45:388-400. [PMID: 24020383 DOI: 10.3109/03602532.2013.835609] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The SULT2b gene family consists of a single gene capable of generating two functional transcripts utilizing different transcriptional start sites in the first exon. This results in the translation of two separate proteins, SULT2B1a and SULT2B1b, with different amino-terminal peptides and approximately 95% identical sequences. The second distinguishing feature of the SULT2B isoforms is the proline/serine-rich carboxy-terminal sequence. To date, presence of the SULT2B gene appears limited to mammals and there is also only limited conservation of structure or sequence of the carboxy-terminal peptide. Although both SULT2B1 messages are present in human tissues, to date, only the SULT2B1b protein has been detected in the tissues investigated. In contrast, selective expression of SULT2B1a has been detected in rodent brain, whereas SULT2B1b was expressed in skin and intestine. Characterization of the SULT2B1 isoforms has been limited by the inability to isolate reliably active SULT2B1b from tissues or cells. SULT2B1 cDNAs can be expressed in Escherichia coli and the expressed active enzymes show selectivity for sulfation of 3β-hydroxysteroids. SULT2B1b due to the binding properties of the amino-terminal peptides also shows high cholesterol sulfation activity. Although human SULT2B1b displays significant substrate cross-reactivity with SULT2A1, the isoforms have different tissue expression patterns. Human SULT2B1b also shows nuclear localization in selected tissues that appears related to serine phosphorylation of the carboxy-terminal peptide. Overall, the understanding of the properties and function of the SULT2B1 isoforms is limited and the structural variability of the unique amino- and carboxy-sequences suggests significant species differences that need to be investigated.
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Affiliation(s)
- Charles N Falany
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham , Birmingham, AL , USA
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Raslan AA, Lee JH, Shin J, Shin YK, Sohn YC. Transcriptional activity and expression of liver X receptor in the ascidian Halocynthia roretzi. Zoolog Sci 2013; 30:731-41. [PMID: 24004079 DOI: 10.2108/zsj.30.731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Liver X receptors, LXRs, are ligand-activated transcription factors that belong to the group H nuclear receptor (NR) superfamily. In this study, an LXR (HrLXR) cDNA was cloned from the ascidian Halocynthia roretzi hepatopancreas and characterized to examine the functional conservation of ancestral LXRs in chordates. A phylogenetic analysis of HrLXR showed that it belongs to the tunicate (urochordate) LXR subgroup, which is distinct from vertebrate LXRs. Quantitative real-time PCR analysis revealed that HrLXR mRNA was expressed predominantly in the gills, and highly expressed in unfertilized eggs followed by decrease at later embryonic and larval stages. Unexpectedly, HrLXR was not activated by GW3965, whereas a synthetic ligand for a farnesoid X receptor, GW4064, activated HrLXR. This activation was abolished by the deletion of 51 amino acids from the N-terminus. In a mammalian two-hybrid system, HrLXR interacted with HrRXR in the presence of GW4064 or 9-cis retinoic acid. The injection of GW3965 and GW4064 in vivo increased the ATPbinding cassette sub-family G member 4 and HrLXR mRNA levels in the hepatopancreas and gills. These results suggest that the mRNA expression and transcriptional properties of HrLXR are different from those of vertebrate LXRs, although HrLXR is likely responsive to the related NR ligand, GW4064.
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Affiliation(s)
- Ahmed Ahmed Raslan
- 1 Department of Marine Molecular Biotechnology, Gangneung-Wonju National University, Gangneung 210-702, Republic of Korea
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de Weille J, Fabre C, Bakalara N. Oxysterols in cancer cell proliferation and death. Biochem Pharmacol 2013; 86:154-60. [PMID: 23500545 DOI: 10.1016/j.bcp.2013.02.029] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/27/2013] [Accepted: 02/27/2013] [Indexed: 12/21/2022]
Abstract
Oxysterols have been shown to interfere with proliferation and cause the death of many cancer cell types, such as leukaemia, glioblastoma, colon, breast and prostate cancer cells, while they have little or no effect on senescent cells. The mechanisms by which oxysterols may influence proliferation are manifold: they control the transcription and the turnover of the key enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl CoA reductase, by binding to Insig-1, Insig-2 and liver X receptors. Oxysterols are thought to be generated in proportion to the rate of cholesterol synthesis. Although there is no consensus about the mechanism by which these oxysterols are generated in vivo, it clearly has to be ubiquitous. The 25- and the 27-cholesterol hydroxylases, present in almost all tissues, are possible candidates. Cholesterol uptake from lipoproteins, intracellular vesicle transport and lipid transfer are also modified by oxysterols. Oxysterols interfere with ERK, hedgehog and wnt pathways of proliferation and differentiation. When administered in vitro to cancer cell lines, oxysterols invariably both slow down proliferation and provoke cell death. Perhaps is it sufficient to stop proliferation of a cancer to provoke its eradication. Therefore, the two facets of oxysterol action that seem important for cancer treatment, cytostaticity and cytotoxicity, will be discussed.
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Affiliation(s)
- Jan de Weille
- Institut des Neurosciences de Montpellier, U1051 INSERM, 80 rue Augustin Fliche, 34295 Montpellier Cedex 05, France.
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de Boussac H, Pommier AJ, Dufour J, Trousson A, Caira F, Volle DH, Baron S, Lobaccaro JMA. LXR, prostate cancer and cholesterol: the Good, the Bad and the Ugly. Am J Cancer Res 2013; 3:58-69. [PMID: 23359865 PMCID: PMC3555197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 12/28/2012] [Indexed: 06/01/2023] Open
Abstract
Cholesterol is a fundamental molecule for life. Located in the cell membrane, this sterol participates to the cell signaling of growth factors. Inside the cell it can be converted in hormones such as androgens or modulate the immune response. Such important functions could not be solely dependent of external supply by diet hence de novo synthesis could occur from acetate in almost all mammalian cells. If a deficiency in cholesterol sourcing leads to development troubles, overstocking has been associated to various diseases such as atherosclerosis and cancers. Cholesterol homeostasis should thus be tightly regulated at the uptake, de novo synthesis, storage and export processes. Various transcription factors have been described these last years as important to regulate cholesterol levels. Besides, synthetic molecules have been developed for many years to modulate cholesterol synthesis, such as statins. Many articles have associated prostate cancer, whose incidence is constantly increasing, to cholesterol disequilibrium. Targeting cholesterol could thus be a new pharmacological hit to counteract the initiation, development and/or progression of prostate cancer. Among the transcription factors regulating cholesterol homeostasis, the nuclear receptors Liver X Receptors (LXRs) control cholesterol uptake and export. Targeting the LXRs offers a new field of investigation to treat cancer. This review highlights the molecular relationships among LXRs, prostate cancer and cholesterol and why LXRs have good chance to be targeted one day in this tumor. LXRs, prostate cancer and cholesterol, more than a "Ménage à trois", The Good, the Bad and the Ugly.
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Affiliation(s)
- Hugues de Boussac
- Clermont Université, Université Blaise Pascal, Génétique Reproduction et Développement F-63000 CLERMONTFERRAND, France ; CNRS, UMR 6293, GReD F-63177 AUBIERE, France ; INSERM, UMR 1103, GReD F-63177 AUBIERE, France ; Centre de Recherche en Nutrition Humaine d'Auvergne F-63000 CLERMONT-FERRAND, France
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Ikegami T, Hyogo H, Honda A, Miyazaki T, Tokushige K, Hashimoto E, Inui K, Matsuzaki Y, Tazuma S. Increased serum liver X receptor ligand oxysterols in patients with non-alcoholic fatty liver disease. J Gastroenterol 2012; 47:1257-66. [PMID: 22569763 DOI: 10.1007/s00535-012-0585-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 03/06/2012] [Indexed: 02/04/2023]
Abstract
BACKGROUND This study is a post-hoc analysis of a subset of patients who participated in our multi-institutional case-control study that evaluated the effects of pitavastatin in patients with non-alcoholic fatty liver disease (NAFLD) with hypercholesterolemia. METHODS Serum samples of fifteen patients with biopsy-proven NAFLD with dyslipidemia were investigated. Serum markers of lipid metabolism were quantified by liquid chromatography-mass spectrometry (LC-MS)/MS. These data were then compared with those of 36 sex- and age-matched healthy controls. In addition, changes in these markers produced by treatment with pitavastatin were evaluated. RESULTS Serum non-cholesterol sterols, reflecting intestinal cholesterol absorption, were significantly lower in the NAFLD patients compared to the controls, and the cholesterol synthesis marker, the ratio of lathosterol to cholesterol, was not significantly different between the two groups. Serum proportions of liver X receptor α (LXRα) ligand oxysterols (ratios to cholesterol) were significantly elevated in the NAFLD patients compared to the controls. The sum of oxysterols relative to cholesterol and the homeostasis model assessment as an index of insulin resistance (HOMA-IR) were significantly correlated. The marker representing cholesterol synthesis was significantly suppressed by pitavastatin treatment, from 3 months after initiation of the treatment, and the suppression remained significant during the observation period. The markers representing cholesterol absorption were unchanged at 3 months, but had significantly increased at 12 months. Serum oxysterol levels relative to cholesterol maintained high values and did not change significantly during the 12-month period of treatment. CONCLUSIONS We speculate that serum LXRα ligand oxysterol levels (relative to cholesterol) could be surrogate markers of insulin resistance, and that high oxysterol levels in the circulation may play an important role in the development of hepatic and peripheral insulin resistance followed by NAFLD.
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Affiliation(s)
- Tadashi Ikegami
- Division of Gastroenterology and Hepatology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, Ami-machi, Inashiki-gun, Ibaraki 300-0395, Japan
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Lecroisey C, Laudet V, Schubert M. The cephalochordate amphioxus: a key to reveal the secrets of nuclear receptor evolution. Brief Funct Genomics 2012; 11:156-66. [PMID: 22441553 DOI: 10.1093/bfgp/els008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The members of the nuclear receptor (NR) superfamily are transcription factors characterized by a particular mode of function, which is related to the conserved nature of their molecular structure. NR proteins usually contain a DNA-binding domain (DBD) and a ligand-binding domain (LBD) allowing them to directly bind to DNA and regulate target gene expression in a ligand-dependent manner. In this review, we are summarizing our current understanding of the NR diversity in the cephalochordate amphioxus, which represents the best available proxy for the last common chordate ancestor both in terms of morphology and genome organization. The amphioxus genome encodes 33 NRs, which is more than expected based on its phylogenetic position, with at least one representative of all major NR groups, excepting NR1E and NR1I/J. This elevated number of receptor genes shows that the amphioxus NR complement has experienced some secondary modifications that are most evident in the NR1H group, which is characterized by three members in humans and ten representatives in amphioxus. By highlighting specific examples of the NR repertoire, including the receptors for retinoic acid, thyroid hormone, estrogen and steroids as well as the bile acid and oxysterol receptors of the NR1H group, we are illustrating the functional diversity of these receptors in amphioxus. We conclude that the amphioxus NRs are valuable models for assessing the evolutionary interplay between receptors and their ligands and that more integrative and comparative approaches are required for assessment of the evolutionary plasticity of receptor-ligand interactions revealed by the studies of amphioxus NRs.
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Affiliation(s)
- Claire Lecroisey
- Institut de Génomique Fonctionnelle de Lyon, UCBL, CNRS UMR, ENSL, INRA, Ecole Normale Supérieure de Lyon, France
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Vanbeselaere J, Chang LY, Harduin-Lepers A, Fabre E, Yamakawa N, Slomianny C, Biot C, Khoo KH, Guerardel Y. Mapping the Expressed Glycome and Glycosyltransferases of Zebrafish Liver Cells as a Relevant Model System for Glycosylation Studies. J Proteome Res 2012; 11:2164-77. [DOI: 10.1021/pr200948j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Jorick Vanbeselaere
- Université Lille Nord de France, Université Lille 1, Unité
de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve
d′Ascq, France
- CNRS, UMR 8576, F-59650 Villeneuve d′Ascq, France
| | - Lan-Yi Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Anne Harduin-Lepers
- Université Lille Nord de France, Université Lille 1, Unité
de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve
d′Ascq, France
- CNRS, UMR 8576, F-59650 Villeneuve d′Ascq, France
| | - Emeline Fabre
- Université Lille Nord de France, Université Lille 1, Unité
de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve
d′Ascq, France
- CNRS, UMR 8576, F-59650 Villeneuve d′Ascq, France
| | - Nao Yamakawa
- Université Lille Nord de France, Université Lille 1, Unité
de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve
d′Ascq, France
- CNRS, UMR 8576, F-59650 Villeneuve d′Ascq, France
| | - Christian Slomianny
- INSERM-LPC, U1003,
Université Lille 1, Cité Scientifique, Bât. SN3,
F-59655 Villeneuve d′Ascq Cedex, France
| | - Christophe Biot
- Université Lille Nord de France, Université Lille 1, Unité
de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve
d′Ascq, France
- CNRS, UMR 8576, F-59650 Villeneuve d′Ascq, France
| | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Yann Guerardel
- Université Lille Nord de France, Université Lille 1, Unité
de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve
d′Ascq, France
- CNRS, UMR 8576, F-59650 Villeneuve d′Ascq, France
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Inhibition of cytochrome P4501-dependent clearance of the endogenous agonist FICZ as a mechanism for activation of the aryl hydrocarbon receptor. Proc Natl Acad Sci U S A 2012; 109:4479-84. [PMID: 22392998 DOI: 10.1073/pnas.1118467109] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Altered systemic levels of 6-formylindolo[3,2-b]carbazole (FICZ), an enigmatic endogenous ligand for the aryl hydrocarbon receptor (AHR), may explain adverse physiological responses evoked by small natural and anthropogenic molecules as well as by oxidative stress and light. We demonstrate here that several different chemical compounds can inhibit the metabolism of FICZ, thereby disrupting the autoregulatory feedback control of cytochrome P4501 systems and other proteins whose expression is regulated by AHR. FICZ is both the most tightly bound endogenous agonist for the AHR and an ideal substrate for cytochrome CYP1A1/1A2 and 1B1, thereby also participating in an autoregulatory loop that keeps its own steady-state concentration low. At very low concentrations FICZ influences circadian rhythms, responses to UV light, homeostasis associated with pro- and anti-inflammatory processes, and genomic stability. Here, we demonstrate that, if its metabolic clearance is compromised, femtomolar background levels of this compound in cell-culture medium are sufficient to up-regulate CYP1A1 mRNA and enzyme activity. The oxidants UVB irradiation and hydrogen peroxide and the model AHR antagonist 3'-methoxy-4'-nitroflavone all inhibited induction of CYP1A1 enzyme activity by FICZ or 2,3,7,8-tetrachlorodibenzo-p-dioxin, thereby subsequently elevating intracellular levels of FICZ and activating AHR. Taken together, these findings support an indirect mechanism of AHR activation, indicating that AHR activation by molecules with low affinity actually may reflect inhibition of FICZ metabolism and raising questions about the reported promiscuity of the AHR. Accordingly, we propose that prolonged induction of AHR activity through inhibition of CYP1 disturbs feedback regulation of FICZ levels, with potential detrimental consequences.
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Archer A, Srinivas Kitambi S, L. Hallgren S, Pedrelli M, Håkan Olsén K, Mode A, Gustafsson JÅ. The Liver X-Receptor (Lxr) Governs Lipid Homeostasis in Zebrafish during Development. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ojemd.2012.24012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fidler AE, Holland PT, Reschly EJ, Ekins S, Krasowski MD. Activation of a tunicate (Ciona intestinalis) xenobiotic receptor orthologue by both natural toxins and synthetic toxicants. Toxicon 2011; 59:365-72. [PMID: 22206814 DOI: 10.1016/j.toxicon.2011.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 12/04/2011] [Accepted: 12/06/2011] [Indexed: 12/21/2022]
Abstract
Vertebrate xenobiotic receptors are ligand-activated nuclear receptors (NRs) that bind exogenous biologically active chemicals before activating the transcription of genes involved in xenobiotic metabolism and excretion. Typically, xenobiotic receptors have ligand binding domains (LBDs) that can accommodate a structurally diverse array of molecules and in addition display high levels of inter-taxa sequence diversity suggestive of positive selection. Pursuing the idea that xenobiotic receptors may adaptively evolve to bind toxic chemicals commonly present in an organism's environment/diet, we examined ligand binding by a xenobiotic receptor orthologue of a marine filter-feeding organism. The solitary tunicate Ciona intestinalis (Phylum Chordata) genome encodes an orthologue of the vertebrate pregnane X receptor (PXR) and vitamin D receptor (VDR), here denoted CiVDR/PXRα. In a luciferase reporter assay the CiVDR/PXRα was activated, at nanomolar concentrations, by two of four natural marine microalgal biotoxins tested (okadaic acid, EC50 = 18.2 ± 0.9 nM and pectenotoxin-2, EC50 = 37.0 ± 3.5 nM) along with 1 of 11 synthetic toxicants (esfenvalerate: EC50 = 0.59 ± 0.7 μM). Two related C. intestinalis NRs, orthologous to vertebrate farnesoid X receptor and liver X receptors, respectively, along with the PXR of a freshwater fish (zebrafish, Danio rerio), were not activated by any of the 15 chemicals tested. In contrast, human PXR was activated by okadaic acid at similar concentrations to CiVDR/PXRα (EC50 = 7.2 ± 1.1 nM) but not by pectenotoxin-2. A common features pharmacophore developed for the CiVDR/PXRα ligand consisted of an off-center hydrogen bond acceptor flanked by two hydrophobic regions. The results of this study are consistent with the original hypothesis that natural toxins, present in the diet of filter-feeding marine invertebrates, may have acted as selective agents in the molecular evolution of tunicate xenobiotic receptors. Bioassays based on tunicate xenobiotic receptor activation may find application in marine environmental monitoring and bioprospecting.
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Affiliation(s)
- Andrew E Fidler
- Cawthron Institute, Private Bag 2, Nelson 7012, New Zealand.
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Cruz-Garcia L, Sánchez-Gurmaches J, Gutiérrez J, Navarro I. Regulation of LXR by fatty acids, insulin, growth hormone and tumor necrosis factor-α in rainbow trout myocytes. Comp Biochem Physiol A Mol Integr Physiol 2011; 160:125-36. [DOI: 10.1016/j.cbpa.2011.05.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 05/15/2011] [Accepted: 05/17/2011] [Indexed: 01/27/2023]
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Ma Q. Influence of light on aryl hydrocarbon receptor signaling and consequences in drug metabolism, physiology and disease. Expert Opin Drug Metab Toxicol 2011; 7:1267-93. [DOI: 10.1517/17425255.2011.614947] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Honda A, Miyazaki T, Ikegami T, Iwamoto J, Maeda T, Hirayama T, Saito Y, Teramoto T, Matsuzaki Y. Cholesterol 25-hydroxylation activity of CYP3A. J Lipid Res 2011; 52:1509-16. [PMID: 21576599 DOI: 10.1194/jlr.m014084] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To date, many studies have been conducted using 25-hydroxycholesterol, which is a potent regulator of lipid metabolism. However, the origins of this oxysterol have not been entirely elucidated. Cholesterol 25-hydroxylase is one of the enzymes responsible for the metabolism of 25-hydroxycholesterol, but the expression of this enzyme is very low in humans. This oxysterol is also synthesized by sterol 27-hydroxylase (CYP27A1) and cholesterol 24-hydroxylase(CYP46A1), but it is only a minor product of these enzymes. We now report that CYP3A synthesizes a significant amount of 25-hydroxycholesterol and may participate in the regulation of lipid metabolism. Induction of CYP3A by pregnenolone-16α-carbonitrile caused the accumulation of 25-hydroxycholesterol in a cell line derived from mouse liver. Furthermore, treatment of the cells with troleandomycin, a specific inhibitor of CYP3A, significantly reduced cellular 25-hydroxycholesterol concentrations. In cells that overexpressed human recombinant CYP3A4, the activity of cholesterol 25-hydroxylation was found to be higher than that of cholesterol 4β-hydroxylation, a known marker activity of CYP3A4. In addition, 25-hydroxycholesterol concentrations in normal human sera correlated positively with the levels of 4β-hydroxycholesterol (r = 0.650, P < 0.0001, n = 78), but did not significantly correlate with the levels of 27-hydroxycholesterol or 24S-hydroxycholesterol. These results demonstrate the significance of CYP3A on the production of 25-hydroxycholesterol.
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Affiliation(s)
- Akira Honda
- Department of Gastroenterology, Center for Collaborative Research, Ibaraki 300-0395, Japan
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Krasowski MD, Ni A, Hagey LR, Ekins S. Evolution of promiscuous nuclear hormone receptors: LXR, FXR, VDR, PXR, and CAR. Mol Cell Endocrinol 2011; 334:39-48. [PMID: 20615451 PMCID: PMC3033471 DOI: 10.1016/j.mce.2010.06.016] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 04/28/2010] [Accepted: 06/29/2010] [Indexed: 12/17/2022]
Abstract
Nuclear hormone receptors (NHRs) are transcription factors that work in concert with co-activators and co-repressors to regulate gene expression. Some examples of ligands for NHRs include endogenous compounds such as bile acids, retinoids, steroid hormones, thyroid hormone, and vitamin D. This review describes the evolution of liver X receptors α and β (NR1H3 and 1H2, respectively), farnesoid X receptor (NR1H4), vitamin D receptor (NR1I1), pregnane X receptor (NR1I2), and constitutive androstane receptor (NR1I3). These NHRs participate in complex, overlapping transcriptional regulation networks involving cholesterol homeostasis and energy metabolism. Some of these receptors, particularly PXR and CAR, are promiscuous with respect to the structurally wide range of ligands that act as agonists. A combination of functional and computational analyses has shed light on the evolutionary changes of NR1H and NR1I receptors across vertebrates, and how these receptors may have diverged from ancestral receptors that first appeared in invertebrates.
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Affiliation(s)
- Matthew D Krasowski
- Department of Pathology, University of Iowa Hospitals and Clinics, RCP 6233, 200 Hawkins Drive, Iowa City, IA 52242, USA.
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Krasowski MD, Ai N, Hagey LR, Kollitz EM, Kullman SW, Reschly EJ, Ekins S. The evolution of farnesoid X, vitamin D, and pregnane X receptors: insights from the green-spotted pufferfish (Tetraodon nigriviridis) and other non-mammalian species. BMC BIOCHEMISTRY 2011; 12:5. [PMID: 21291553 PMCID: PMC3042382 DOI: 10.1186/1471-2091-12-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 02/03/2011] [Indexed: 12/23/2022]
Abstract
Background The farnesoid X receptor (FXR), pregnane X receptor (PXR), and vitamin D receptor (VDR) are three closely related nuclear hormone receptors in the NR1H and 1I subfamilies that share the property of being activated by bile salts. Bile salts vary significantly in structure across vertebrate species, suggesting that receptors binding these molecules may show adaptive evolutionary changes in response. We have previously shown that FXRs from the sea lamprey (Petromyzon marinus) and zebrafish (Danio rerio) are activated by planar bile alcohols found in these two species. In this report, we characterize FXR, PXR, and VDR from the green-spotted pufferfish (Tetraodon nigriviridis), an actinopterygian fish that unlike the zebrafish has a bile salt profile similar to humans. We utilize homology modelling, docking, and pharmacophore studies to understand the structural features of the Tetraodon receptors. Results Tetraodon FXR has a ligand selectivity profile very similar to human FXR, with strong activation by the synthetic ligand GW4064 and by the primary bile acid chenodeoxycholic acid. Homology modelling and docking studies suggest a ligand-binding pocket architecture more similar to human and rat FXRs than to lamprey or zebrafish FXRs. Tetraodon PXR was activated by a variety of bile acids and steroids, although not by the larger synthetic ligands that activate human PXR such as rifampicin. Homology modelling predicts a larger ligand-binding cavity than zebrafish PXR. We also demonstrate that VDRs from the pufferfish and Japanese medaka were activated by small secondary bile acids such as lithocholic acid, whereas the African clawed frog VDR was not. Conclusions Our studies provide further evidence of the relationship between both FXR, PXR, and VDR ligand selectivity and cross-species variation in bile salt profiles. Zebrafish and green-spotted pufferfish provide a clear contrast in having markedly different primary bile salt profiles (planar bile alcohols for zebrafish and sterically bent bile acids for the pufferfish) and receptor selectivity that matches these differences in endogenous ligands. Our observations to date present an integrated picture of the co-evolution of bile salt structure and changes in the binding pockets of three nuclear hormone receptors across the species studied.
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Affiliation(s)
- Matthew D Krasowski
- Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA.
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Abstract
Normally macrophages localized in the arterial vessel wall perform the "reverse transfer" of cholesterol, which includes endocytosis of low density lipoproteins (LDL), cholesterol transfer to newly formed high density lipoprotein particles, and their following elimination by the liver. The homeostatic function of macrophages for cholesterol involves a system of lipid sensors. Oxysterol sensors LXRs, oxysterol and cholesterol sensors INSIG and SCAP acting through controlled transcription factors SREBP, as well as sensors for oxidized fatty acids and their derivatives, PPAR, are the best studied. Activation of LXR and PPAR is also accompanied by inhibition of macrophage functions related to inflammation. Accumulation of oxidized and otherwise modified LDL in the subendothelial space induced by endothelium injury, infection, or other pathogenic factors instead of stimulation of the homeostatic functions of macrophages leads to their weakening with a concurrent increase in the inflammatory potential of these cells. These shifts seem to drive the transformation of macrophages into foam cells, which form the core of sclerotic plaques. The intervention of another lipid sensor, TLR4, can trigger such a radical change in the functional activity of macrophages. The interaction of modified LDL with this signaling receptor results in inhibition of the homeostatic oxysterol signaling, induction of additional LDL transporters, and activation of the phagocytic function of macrophages. The re-establishment of cholesterol homeostasis under these circumstances can be achieved by administration of LXR and PPARgamma agonists. Therefore, it is urgent to design ligands with reduced side effects.
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The tryptophan photoproduct 6-formylindolo[3,2-b]carbazole helps genes jump. Proc Natl Acad Sci U S A 2010; 107:18239-40. [PMID: 20944064 DOI: 10.1073/pnas.1013653107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Kortagere S, Krasowski MD, Reschly EJ, Venkatesh M, Mani S, Ekins S. Evaluation of computational docking to identify pregnane X receptor agonists in the ToxCast database. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1412-1417. [PMID: 20558333 PMCID: PMC2957921 DOI: 10.1289/ehp.1001930] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 06/17/2010] [Indexed: 05/29/2023]
Abstract
BACKGROUND The pregnane X receptor (PXR) is a key transcriptional regulator of many genes [e.g., cytochrome P450s (CYP2C9, CYP3A4, CYP2B6), MDR1] involved in xenobiotic metabolism and excretion. OBJECTIVES As part of an evaluation of different approaches to predict compound affinity for nuclear hormone receptors, we used the molecular docking program GOLD and a hybrid scoring scheme based on similarity weighted GoldScores to predict potential PXR agonists in the ToxCast database of pesticides and other industrial chemicals. We present some of the limitations of different in vitro systems, as well as docking and ligand-based computational models. METHODS Each ToxCast compound was docked into the five published crystallographic structures of human PXR (hPXR), and 15 compounds were selected based on their consensus docking scores for testing. In addition, we used a Bayesian model to classify the ToxCast compounds into PXR agonists and nonagonists. hPXR activation was determined by luciferase-based reporter assays in the HepG2 and DPX-2 human liver cell lines. RESULTS We tested 11 compounds, of which 6 were strong agonists and 2 had weak agonist activity. Docking results of additional compounds were compared with data reported in the literature. The prediction sensitivity of PXR agonists in our sample ToxCast data set (n = 28) using docking and the GoldScore was higher than with the hybrid score at 66.7%. The prediction sensitivity for PXR agonists using GoldScore for the entire ToxCast data set (n = 308) compared with data from the NIH (National Institutes of Health) Chemical Genomics Center data was 73.8%. CONCLUSIONS Docking and the GoldScore may be useful for prioritizing large data sets prior to in vitro testing with good sensitivity across the sample and entire ToxCast data set for hPXR agonists.
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Affiliation(s)
- Sandhya Kortagere
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Matthew D. Krasowski
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Erica J. Reschly
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Madhukumar Venkatesh
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Sridhar Mani
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Sean Ekins
- Collaborations in Chemistry, Jenkintown, Pennsylvania, USA
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland, USA
- Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, USA
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Hagey LR, Møller PR, Hofmann AF, Krasowski MD. Diversity of bile salts in fish and amphibians: evolution of a complex biochemical pathway. Physiol Biochem Zool 2010; 83:308-21. [PMID: 20113173 PMCID: PMC2845723 DOI: 10.1086/649966] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Bile salts are the major end metabolites of cholesterol and are also important in lipid and protein digestion, as well as shaping of the gut microflora. Previous studies had demonstrated variation of bile salt structures across vertebrate species. We greatly extend prior surveys of bile salt variation in fish and amphibians, particularly in analysis of the biliary bile salts of Agnatha and Chondrichthyes. While there is significant structural variation of bile salts across all fish orders, bile salt profiles are generally stable within orders of fish and do not correlate with differences in diet. This large data set allowed us to infer evolutionary changes in the bile salt synthetic pathway. The hypothesized ancestral bile salt synthetic pathway, likely exemplified in extant hagfish, is simpler and much shorter than the pathway of most teleost fish and terrestrial vertebrates. Thus, the bile salt synthetic pathway has become longer and more complex throughout vertebrate evolution. Analysis of the evolution of bile salt synthetic pathways provides a rich model system for the molecular evolution of a complex biochemical pathway in vertebrates.
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Affiliation(s)
- Lee R. Hagey
- Department of Medicine, University of California at San Diego, MC 0063, La Jolla, California 92093-0063
| | - Peter R. Møller
- National History Museum of Denmark, Zoological Museum, University of Copenhagen, Denmark
| | - Alan F. Hofmann
- Department of Medicine, University of California at San Diego, MC 0063, La Jolla, California 92093-0063
| | - Matthew D. Krasowski
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261
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