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Belyaeva OV, Klyuyeva AV, Vyas A, Berger WK, Halasz L, Yu J, Atigadda VR, Slay A, Goggans KR, Renfrow MB, Kane MA, Nagy L, Kedishvili NY. The retinoid X receptor has a critical role in synthetic rexinoid-induced increase in cellular all-trans-retinoic acid. PLoS One 2024; 19:e0301447. [PMID: 38557762 PMCID: PMC10984533 DOI: 10.1371/journal.pone.0301447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
Rexinoids are agonists of nuclear rexinoid X receptors (RXR) that heterodimerize with other nuclear receptors to regulate gene transcription. A number of selective RXR agonists have been developed for clinical use but their application has been hampered by the unwanted side effects associated with the use of rexinoids and a limited understanding of their mechanisms of action across different cell types. Our previous studies showed that treatment of organotypic human epidermis with the low toxicity UAB30 and UAB110 rexinoids resulted in increased steady-state levels of all-trans-retinoic acid (ATRA), the obligatory ligand of the RXR-RAR heterodimers. Here, we investigated the molecular mechanism underlying the increase in ATRA levels using a dominant negative RXRα that lacks the activation function 2 (AF-2) domain. The results demonstrated that overexpression of dnRXRα in human organotypic epidermis markedly reduced signaling by resident ATRA, suggesting the existence of endogenous RXR ligand, diminished the biological effects of UAB30 and UAB110 on epidermis morphology and gene expression, and nearly abolished the rexinoid-induced increase in ATRA levels. Global transcriptome analysis of dnRXRα-rafts in comparison to empty vector-transduced rafts showed that over 95% of the differentially expressed genes in rexinoid-treated rafts constitute direct or indirect ATRA-regulated genes. Thus, the biological effects of UAB30 and UAB110 are mediated through the AF-2 domain of RXRα with minimal side effects in human epidermis. As ATRA levels are known to be reduced in certain epithelial pathologies, treatment with UAB30 and UAB110 may represent a promising therapy for normalizing the endogenous ATRA concentration and signaling in epithelial tissues.
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Affiliation(s)
- Olga V. Belyaeva
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Alla V. Klyuyeva
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Ansh Vyas
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Wilhelm K. Berger
- Departments of Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, United States of America
| | - Laszlo Halasz
- Departments of Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, United States of America
| | - Jianshi Yu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, United States of America
| | - Venkatram R. Atigadda
- Department of Dermatology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Aja Slay
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Kelli R. Goggans
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Matthew B. Renfrow
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, United States of America
| | - Laszlo Nagy
- Departments of Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, United States of America
| | - Natalia Y. Kedishvili
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America
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Almeida NMS, Bali SK, James D, Wang C, Wilson AK. Binding of Per- and Polyfluoroalkyl Substances (PFAS) to the PPARγ/RXRα-DNA Complex. J Chem Inf Model 2023; 63:7423-7443. [PMID: 37990410 DOI: 10.1021/acs.jcim.3c01384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Nuclear receptors are the fundamental building blocks of gene expression regulation and the focus of many drug targets. While binding to DNA, nuclear receptors act as transcription factors, governing a multitude of functions in the human body. Peroxisome proliferator-activator receptor γ (PPARγ) and the retinoid X receptor α (RXRα) form heterodimers with unique properties and have a primordial role in insulin sensitization. This PPARγ/RXRα heterodimer has been shown to be impacted by per- and polyfluoroalkyl substances (PFAS) and linked to a variety of significant health conditions in humans. Herein, a selection of the most common PFAS (legacy and emerging) was studied utilizing molecular dynamics simulations for PPARγ/RXRα. The local and global structural effects of PFAS binding on the known ligand binding pockets of PPARγ and RXRα as well as the DNA binding domain (DBD) of RXRα were inspected. The binding free energies were predicted computationally and were compared between the different binding pockets. In addition, two electronic structure approaches were utilized to model the interaction of PFAS within the DNA binding domain, density functional theory (DFT) and domain-based pair natural orbital coupled cluster with perturbative triples (DLPNO-CCSD(T)) approaches, with implicit solvation. Residue decomposition and hydrogen-bonding analysis were also performed, detailing the role of prominent residues in molecular recognition. The role of l-carnitine is explored as a potential in vivo remediation strategy for PFAS interaction with the PPARγ/RXRα heterodimer. In this work, it was found that PFAS can bind and act as agonists for all of the investigated pockets. For the first time in the literature, PFAS are postulated to bind to the DNA binding domain in a nonspecific manner. In addition, for the PPARγ ligand binding domain, l-carnitine shows promise in replacing smaller PFAS from the pocket.
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Affiliation(s)
- Nuno M S Almeida
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, United States
| | - Semiha Kevser Bali
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, United States
| | - Deepak James
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, United States
| | - Cong Wang
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, United States
| | - Angela K Wilson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, United States
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3
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Leal AS, Hung PY, Chowdhury AS, Liby KT. Retinoid X Receptor agonists as selective modulators of the immune system for the treatment of cancer. Pharmacol Ther 2023; 252:108561. [PMID: 37952906 DOI: 10.1016/j.pharmthera.2023.108561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 11/14/2023]
Abstract
Upon heterodimerizing with other nuclear receptors, retinoid X receptors (RXR) act as ligand-dependent transcription factors, regulating transcription of critical signaling pathways that impact numerous hallmarks of cancer. By controlling both inflammation and immune responses, ligands that activate RXR can modulate the tumor microenvironment. Several small molecule agonists of these essential receptors have been synthesized. Historically, RXR agonists were tested for inhibition of growth in cancer cells, but more recent drug discovery programs screen new molecules for inhibition of inflammation or activation of immune cells. Bexarotene is the first successful example of an effective therapeutic that molecularly targets RXR; this drug was approved to treat cutaneous T cell lymphoma and is still used as a standard of care treatment for this disease. No additional RXR agonists have yet achieved FDA approval, but several promising novel compounds are being developed. In this review, we provide an overview of the multiple mechanisms by which RXR signaling regulates inflammation and tumor immunity. We also discuss the potential of RXR-dependent immune cell modulation for the treatment or prevention of cancer and concomitant challenges and opportunities.
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Affiliation(s)
- Ana S Leal
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States of America; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Pei-Yu Hung
- Department of Physiology, Michigan State University, East Lansing, MI, United States of America
| | - Afrin Sultana Chowdhury
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Karen T Liby
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States of America; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America.
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Sharma S, Shen T, Chitranshi N, Gupta V, Basavarajappa D, Mirzaei M, You Y, Krezel W, Graham SL, Gupta V. Retinoid X Receptor: Cellular and Biochemical Roles of Nuclear Receptor with a Focus on Neuropathological Involvement. Mol Neurobiol 2022; 59:2027-2050. [PMID: 35015251 PMCID: PMC9015987 DOI: 10.1007/s12035-021-02709-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022]
Abstract
Retinoid X receptors (RXRs) present a subgroup of the nuclear receptor superfamily with particularly high evolutionary conservation of ligand binding domain. The receptor exists in α, β, and γ isotypes that form homo-/heterodimeric complexes with other permissive and non-permissive receptors. While research has identified the biochemical roles of several nuclear receptor family members, the roles of RXRs in various neurological disorders remain relatively under-investigated. RXR acts as ligand-regulated transcription factor, modulating the expression of genes that plays a critical role in mediating several developmental, metabolic, and biochemical processes. Cumulative evidence indicates that abnormal RXR signalling affects neuronal stress and neuroinflammatory networks in several neuropathological conditions. Protective effects of targeting RXRs through pharmacological ligands have been established in various cell and animal models of neuronal injury including Alzheimer disease, Parkinson disease, glaucoma, multiple sclerosis, and stroke. This review summarises the existing knowledge about the roles of RXR, its interacting partners, and ligands in CNS disorders. Future research will determine the importance of structural and functional heterogeneity amongst various RXR isotypes as well as elucidate functional links between RXR homo- or heterodimers and specific physiological conditions to increase drug targeting efficiency in pathological conditions.
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Affiliation(s)
- Samridhi Sharma
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Ting Shen
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Nitin Chitranshi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Devaraj Basavarajappa
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mehdi Mirzaei
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Yuyi You
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.,Save Sight Institute, University of Sydney, Sydney, NSW, Australia
| | - Wojciech Krezel
- Institut de Génétique Et de Biologie Moléculaire Et Cellulaire, INSERM U1258, CNRS UMR 7104, Unistra, 67404, Illkirch-Graffenstaden, France
| | - Stuart L Graham
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.,Save Sight Institute, University of Sydney, Sydney, NSW, Australia
| | - Vivek Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.
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5
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RXR – centralny regulator wielu ścieżek sygnałowych w organizmie. POSTEP HIG MED DOSW 2021. [DOI: 10.2478/ahem-2021-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstrakt
Receptory jądrowe (NRs) tworzą największą nadrodzinę czynników transkrypcyjnych, które odgrywają ważną rolę w regulacji wielu procesów biologicznych. Receptor kwasu 9-cis-retinowego (RXR) wydaje się odgrywać szczególną rolę wśród tej grupy białek, a to ma związek z jego zdolnością do tworzenia dimerów z innymi NRs. Ze względu na kontrolę ekspresji wielu genów, RXR stanowi bardzo dobry cel licznych terapii. Nieprawidłowości w szlakach modulowanych przez RXR są powiązane m.in. z chorobami neurodegeneracyjnymi, otyłością, cukrzycą, a także nowotworami. Istnieje wiele związków mogących regulować aktywność transkrypcyjną RXR. Jednak obecnie dopuszczonych do użytku klinicznego jest tylko kilka z nich. Retinoidy normalizują wzrost i różnicowanie komórek skóry i błon śluzowych, ponadto działają immunomodulująco oraz przeciwzapalnie. Stąd są stosowane przede wszystkim w chorobach skóry i w terapii niektórych chorób nowotworowych. W artykule przedstawiono ogólne wiadomości na temat RXR, jego budowy, ligandów i mechanizmu działania oraz potencjalnej roli w terapii nowotworów i zespołu metabolicznego.
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Brtko J, Dvorak Z. Natural and synthetic retinoid X receptor ligands and their role in selected nuclear receptor action. Biochimie 2020; 179:157-168. [PMID: 33011201 DOI: 10.1016/j.biochi.2020.09.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/22/2020] [Accepted: 09/30/2020] [Indexed: 02/06/2023]
Abstract
Important key players in the regulatory machinery within the cells are nuclear retinoid X receptors (RXRs), which compose heterodimers in company with several diverse nuclear receptors, playing a role as ligand inducible transcription factors. In general, nuclear receptors are ligand-activated, transcription-modulating proteins affecting transcriptional responses in target genes. RXR molecules forming permissive heterodimers with disparate nuclear receptors comprise peroxisome proliferator-activated receptors (PPARs), liver X receptors (LXRs), farnesoid X receptor (FXR), pregnane X receptor (PXR) and constitutive androstan receptor (CAR). Retinoid receptors (RARs) and thyroid hormone receptors (TRs) may form conditional heterodimers, and dihydroxyvitamin D3 receptor (VDR) is believed to form nonpermissive heterodimer. Thus, RXRs are the important molecules that are involved in control of many cellular functions in biological processes and diseases, including cancer or diabetes. This article summarizes both naturally occurring and synthetic ligands for nuclear retinoid X receptors and describes, predominantly in mammals, their role in molecular mechanisms within the cells. A focus is also on triorganotin compounds, which are high affinity RXR ligands, and finally, we present an outlook on human microbiota as a potential source of RXR activators. Nevertheless, new synthetic rexinoids with better retinoid X receptor activity and lesser side effects are highly required.
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Affiliation(s)
- Julius Brtko
- Institute of Experimental Endocrinology, Biomedical Center of the Slovak Academy of Sciences, Dubravska cesta 9, 845 05, Bratislava, Slovak Republic.
| | - Zdenek Dvorak
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 11, 783 71, Olomouc, Czech Republic
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Kim EH, Kim GA, Taweechaipaisankul A, Ridlo MR, Lee SH, Ra K, Ahn C, Lee BC. Phytanic acid-derived peroxisomal lipid metabolism in porcine oocytes. Theriogenology 2020; 157:276-285. [PMID: 32823023 DOI: 10.1016/j.theriogenology.2020.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022]
Abstract
Lipid metabolism plays an important role in oocyte maturation. The peroxisome is the fundamental mediator for this mechanism. In this study, we investigated the peroxisomal lipid metabolism in porcine oocytes. Phytanic acid (PA) was chosen as an activator of alpha-oxidation in peroxisomes. Oocyte maturation, embryo development, immunocytochemistry of peroxisomal lipid activities, and staining of mitochondrial potentials were assessed. We found that 40 μM PA not only increased porcine oocyte maturation and embryonic development, but also upregulated the expression of genes and proteins related to activities of the peroxisomal lipid metabolism (PHYH, PEX19, and PEX subfamilies) and mitochondrial potentials (NRF1 and PGC1α). Moreover, PA upregulated the lipid droplet and fatty acid content in the oocytes. Moreover, mitochondria were activated and the mitochondrial membrane potential was increased after PA treatment, resulting in the production of more ATPs in the oocytes. Our findings suggest that the degradation of PA via alpha-oxidation in the peroxisome may potentiate oocyte maturation processes, peroxisomal lipid oxidation, and mitochondria activities.
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Affiliation(s)
- Eui Hyun Kim
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Geon A Kim
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Department of Biomedical Laboratory Science, School of Medicine, Eulji University, Daejeon, Republic of Korea
| | - Anukul Taweechaipaisankul
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Muhammad Rosyid Ridlo
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Department of Bioresource Technology and Veterinary, Vocational College, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Seok Hee Lee
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Kihae Ra
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Curie Ahn
- Division of Nephrology, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Byeong Chun Lee
- Department of Theriogenology and Biotechnology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
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9
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Schierle S, Merk D. Therapeutic modulation of retinoid X receptors – SAR and therapeutic potential of RXR ligands and recent patents. Expert Opin Ther Pat 2019; 29:605-621. [DOI: 10.1080/13543776.2019.1643322] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Simone Schierle
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Daniel Merk
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
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10
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Chitranshi N, Dheer Y, Kumar S, Graham SL, Gupta V. Molecular docking, dynamics, and pharmacology studies on bexarotene as an agonist of ligand-activated transcription factors, retinoid X receptors. J Cell Biochem 2019; 120:11745-11760. [PMID: 30746761 DOI: 10.1002/jcb.28455] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 01/24/2023]
Abstract
Retinoid X receptors (RXRs) belong to the nuclear receptor superfamily, and upon ligand activation, these receptors control gene transcription via either homodimerization with themselves or heterodimerization with the partner-nuclear receptor. The protective effects of RXRs and RXR agonists have been reported in several neurodegenerative diseases, including in the retina. This study was aimed to prioritize compounds from natural and synthetic origin retinoids as potential RXR agonists by molecular docking and molecular dynamic simulation strategies. The docking studies indicated bexarotene as a lead compound that can activate various RXR receptor isoforms (α, β, and γ) and has a strong binding affinity to the receptor protein than retinoic acid, which is known as a natural endogenous RXR agonist. Dynamic simulation studies confirmed that the hydrogen bonding and hydrophobic interactions were highly stable in all the three isoforms of the RXR-bexarotene complex. To further validate the significance of the RXR receptor in neurons, in vitro pharmacological treatment of neuronal SH-SY5Y cells with bexarotene was performed. In vitro data from SH-SY5Y cells confirmed that bexarotene activated RXR-simulated neurite outgrowth significantly. We conclude that bexarotene could be potentially used as an exogenous activator of RXRs and emerge as a good drug target for several neurodegenerative disorders.
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Affiliation(s)
- Nitin Chitranshi
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
| | - Yogita Dheer
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
| | - Sanjay Kumar
- Bioinformatics Centre, Biotech Park, Jankipuram, Lucknow, Uttar Pradesh, India
| | - Stuart L Graham
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
- Save Sight Institute, Sydney University, Sydney, New South Wales, Australia
| | - Vivek Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
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11
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Dubot P, Astudillo L, Touati G, Baruteau J, Broué P, Roche S, Sabourdy F, Levade T. Pregnancy outcome in Refsum disease: Affected fetuses and children born to an affected mother. JIMD Rep 2019; 46:11-15. [PMID: 31240149 PMCID: PMC6498833 DOI: 10.1002/jmd2.12020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 11/06/2022] Open
Abstract
We describe the case of a young woman, from a consanguineous family, affected by adult Refsum disease (ARD, OMIM#266500). ARD is a rare peroxisomal autosomal recessive disease due to deficient alpha-oxidation of phytanic acid (PA), a branched-chain fatty acid. The accumulation of PA in organs is thought to be responsible for disease symptoms. The patient presented only bilateral shortening of metatarsals and has been treated with a low-PA diet. She is homoallelic for the c.135-2A > G mutation of PHYH, and she married her first cousin carrying the same mutation. She was pregnant seven times and had two homozygous girls. Due to a potential exacerbation of the disease during the third trimester of pregnancy, her weight and plasma PA levels were monitored. No specific events were noticed for the mother during the pregnancies and postpartum periods. This case also raised the question of potential exposure to PA (and its subsequent toxicity) of a homozygous fetus in a homozygous mother. Despite modestly elevated plasma concentrations of PA at birth (<30 μmol/L), the two affected girls did not present any specific sign of ARD and have so far developed normally. As only a few determinations of plasma PA levels in the mother could be performed during pregnancies, showing mild elevations (<350 μmol/L), it remains difficult to conclude as to a possible transplacental crossing of PA.
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Affiliation(s)
- Patricia Dubot
- Laboratoire de Biochimie MétaboliqueCentre de Référence en Maladies Héréditaires du Métabolisme, Institut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM UMR1037CRCT (Cancer Research Center of Toulouse)ToulouseFrance
| | - Léonardo Astudillo
- INSERM UMR1037CRCT (Cancer Research Center of Toulouse)ToulouseFrance
- Service de Médecine InterneCentre de Référence en Maladies Héréditaires du Métabolisme, CHU de ToulouseToulouseFrance
| | - Guy Touati
- Département d'Hépato‐gastroentérologie pédiatrique, Centre de Référence en Maladies Héréditaires du MétabolismeHôpital des Enfants, CHU de ToulouseToulouseFrance
| | - Julien Baruteau
- Département d'Hépato‐gastroentérologie pédiatrique, Centre de Référence en Maladies Héréditaires du MétabolismeHôpital des Enfants, CHU de ToulouseToulouseFrance
| | - Pierre Broué
- Département d'Hépato‐gastroentérologie pédiatrique, Centre de Référence en Maladies Héréditaires du MétabolismeHôpital des Enfants, CHU de ToulouseToulouseFrance
| | - Sandrine Roche
- Département d'Hépato‐gastroentérologie pédiatrique, Centre de Référence en Maladies Héréditaires du MétabolismeHôpital des Enfants, CHU de ToulouseToulouseFrance
| | - Frédérique Sabourdy
- Laboratoire de Biochimie MétaboliqueCentre de Référence en Maladies Héréditaires du Métabolisme, Institut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM UMR1037CRCT (Cancer Research Center of Toulouse)ToulouseFrance
| | - Thierry Levade
- Laboratoire de Biochimie MétaboliqueCentre de Référence en Maladies Héréditaires du Métabolisme, Institut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM UMR1037CRCT (Cancer Research Center of Toulouse)ToulouseFrance
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Chen L, Wu L, Zhu L, Zhao Y. Overview of the structure-based non-genomic effects of the nuclear receptor RXRα. Cell Mol Biol Lett 2018; 23:36. [PMID: 30093910 PMCID: PMC6080560 DOI: 10.1186/s11658-018-0103-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/27/2018] [Indexed: 12/12/2022] Open
Abstract
The nuclear receptor RXRα (retinoid X receptor-α) is a transcription factor that regulates the expression of multiple genes. Its non-genomic function is largely related to its structure, polymeric forms and modification. Previous research revealed that some non-genomic activity of RXRα occurs via formation of heterodimers with Nur77. RXRα-Nur77 heterodimers translocate from the nucleus to the mitochondria in response to certain apoptotic stimuli and this activity correlates with cell apoptosis. More recent studies revealed a significant role for truncated RXRα (tRXRα), which interacts with the p85α subunit of the PI3K/AKT signaling pathway, leading to enhanced activation of AKT and promoting cell growth in vitro and in animals. We recently reported on a series of NSAID sulindac analogs that can bind to tRXRα through a unique binding mechanism. We also identified one analog, K-80003, which can inhibit cancer cell growth by inducing tRXRα to form a tetramer, thus disrupting p85α-tRXRα interaction. This review analyzes the non-genomic effects of RXRα in normal and tumor cells, and discusses the functional differences based on RXRα protein structure (structure source: the RCSB Protein Data Bank).
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Affiliation(s)
- Liqun Chen
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108 China
| | - Lingjuan Wu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108 China
| | - Linyan Zhu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108 China
| | - Yiyi Zhao
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108 China
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Hiebl V, Ladurner A, Latkolik S, Dirsch VM. Natural products as modulators of the nuclear receptors and metabolic sensors LXR, FXR and RXR. Biotechnol Adv 2018; 36:1657-1698. [PMID: 29548878 DOI: 10.1016/j.biotechadv.2018.03.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/02/2018] [Accepted: 03/08/2018] [Indexed: 01/25/2023]
Abstract
Nuclear receptors (NRs) represent attractive targets for the treatment of metabolic syndrome-related diseases. In addition, natural products are an interesting pool of potential ligands since they have been refined under evolutionary pressure to interact with proteins or other biological targets. This review aims to briefly summarize current basic knowledge regarding the liver X (LXR) and farnesoid X receptors (FXR) that form permissive heterodimers with retinoid X receptors (RXR). Natural product-based ligands for these receptors are summarized and the potential of LXR, FXR and RXR as targets in precision medicine is discussed.
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Affiliation(s)
- Verena Hiebl
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
| | - Angela Ladurner
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria.
| | - Simone Latkolik
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
| | - Verena M Dirsch
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
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Toxic effects of phytol and retinol on human glioblastoma cells are associated with modulation of cholesterol and fatty acid biosynthetic pathways. J Neurooncol 2017; 136:435-443. [PMID: 29159775 DOI: 10.1007/s11060-017-2672-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/11/2017] [Indexed: 02/07/2023]
Abstract
Glioblastoma (GBM) is the most common primary brain tumor. Genetic mutations may reprogram the metabolism of neoplastic cells. Particularly, alterations in cholesterol and fatty acid biosynthetic pathways may favor biomass synthesis and resistance to therapy. Therefore, compounds that interfere with those pathways, such as phytol (PHY) and retinol (RET), may be appropriate for cytotoxic approaches. We tested the effect of PHY or RET on the viability of human GBM cell lines (U87MG, A172 and T98G). Since the compounds showed a dose-dependent cytotoxic effect, additional analyses were performed with IC50 values. Transcriptome analyses of A172 cells treated with PHY IC50 or RET IC50 revealed down-regulated genes involved in cholesterol and/or fatty acid biosynthetic pathways. Thus, we investigated the expression of proteins required for cholesterol and/or fatty acid synthesis after treating all lineages with PHY IC50 or RET IC50 and comparing them with controls. Sterol regulatory element-binding protein 1 (SREBP-1) expression was reduced by PHY in U87 and T98G cells. However, fatty acid synthase (FAS) protein expression, which is regulated by SREBP-1, was down-regulated in all lineages after both treatments. Moreover, farnesyl-diphosphate farnesyltransferase (FDFT1) levels, a protein associated with cholesterol synthesis, were reduced in all lineages by PHY and in U87MG and A172 cells by RET. Our results suggest that SREBP-1, FAS and FDFT1 are potential target(s) for future in vivo approaches against GBM and support the use of inhibitors of their synthesis, including PHY and RET, for such approaches.
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McIntosh AL, Storey SM, Huang H, Kier AB, Schroeder F. Sex-dependent impact of Scp-2/Scp-x gene ablation on hepatic phytol metabolism. Arch Biochem Biophys 2017; 635:17-26. [PMID: 29051070 DOI: 10.1016/j.abb.2017.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/10/2017] [Accepted: 10/14/2017] [Indexed: 12/19/2022]
Abstract
While prior studies focusing on male mice suggest a role for sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x; DKO) on hepatic phytol metabolism, its role in females is unresolved. This issue was addressed using female and male wild-type (WT) and DKO mice fed a phytoestrogen-free diet without or with 0.5% phytol. GC/MS showed that hepatic: i) phytol was absent and its branched-chain fatty acid (BCFA) metabolites were barely detectable in WT control-fed mice; ii) accumulation of phytol as well as its peroxisomal metabolite BCFAs (phytanic acid » pristanic and 2,3-pristenic acids) was increased by dietary phytol in WT females, but only slightly in WT males; iii) accumulation of phytol and BCFA was further increased by DKO in phytol-fed females, but much more markedly in males. Livers of phytol-fed WT female mice as well as phytol-fed DKO female and male mice also accumulated increased proportion of saturated straight-chain fatty acids (LCFA) at the expense of unsaturated LCFA. Liver phytol accumulation was not due to increased SCP-2 binding/transport of phytol since SCP-2 bound phytanic acid, but not its precursor phytol. Thus, the loss of Scp-2/Scp-x contributed to a sex-dependent hepatic accumulation of dietary phytol and BCFA.
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Affiliation(s)
- Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Stephen M Storey
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Huan Huang
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843-4467, United States
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States.
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Schönfeld P, Reiser G. Brain energy metabolism spurns fatty acids as fuel due to their inherent mitotoxicity and potential capacity to unleash neurodegeneration. Neurochem Int 2017; 109:68-77. [PMID: 28366720 DOI: 10.1016/j.neuint.2017.03.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 03/20/2017] [Accepted: 03/24/2017] [Indexed: 12/21/2022]
Abstract
The brain uses long-chain fatty acids (LCFAs) to a negligible extent as fuel for the mitochondrial energy generation, in contrast to other tissues that also demand high energy. Besides this generally accepted view, some studies using cultured neural cells or whole brain indicate a moderately active mitochondrial β-oxidation. Here, we corroborate the conclusion that brain mitochondria are unable to oxidize fatty acids. In contrast, the combustion of liver-derived ketone bodies by neural cells is long-known. Furthermore, new insights indicate the use of odd-numbered medium-chain fatty acids as valuable source for maintaining the level of intermediates of the citric acid cycle in brain mitochondria. Non-esterified LCFAs or their activated forms exert a large variety of harmful side-effects on mitochondria, such as enhancing the mitochondrial ROS generation in distinct steps of the β-oxidation and therefore potentially increasing oxidative stress. Hence, the question arises: Why do in brain energy metabolism mitochondria selectively spurn LCFAs as energy source? The most likely answer are the relatively higher content of peroxidation-sensitive polyunsaturated fatty acids and the low antioxidative defense in brain tissue. There are two remarkable peroxisomal defects, one relating to α-oxidation of phytanic acid and the other to uptake of very long-chain fatty acids (VLCFAs) which lead to pathologically high tissue levels of such fatty acids. Both, the accumulation of phytanic acid and that of VLCFAs give an enlightening insight into harmful activities of fatty acids on neural cells, which possibly explain why evolution has prevented brain mitochondria from the equipment with significant β-oxidation enzymatic capacity.
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Affiliation(s)
- Peter Schönfeld
- Institut für Biochemie und Zellbiologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany
| | - Georg Reiser
- Institut für Inflammation und Neurodegeneration (Neurobiochemie), Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany.
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de Lera ÁR, Krezel W, Rühl R. An Endogenous Mammalian Retinoid X Receptor Ligand, At Last! ChemMedChem 2016; 11:1027-37. [PMID: 27151148 DOI: 10.1002/cmdc.201600105] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/15/2016] [Indexed: 12/27/2022]
Abstract
9-cis-Retinoic acid was identified and claimed to be the endogenous ligand of the retinoid X receptors (RXRs) in 1992. Since then, the endogenous presence of this compound has never been rigorously confirmed. Instead, concerns have been raised by other groups that have reported that 9-cis-retinoic acid is undetectable or that its presence occurs at very low levels. Furthermore, these low levels could not satisfactorily explain the physiological activation of RXR. Alternative ligands, among them various lipids, have also been identified, but also did not fulfill criteria for rigorous endogenous relevance, and their consideration as bona fide endogenous mammalian RXR ligand has likewise been questioned. Recently, novel studies claim that the saturated analogue 9-cis-13,14-dihydroretinoic acid functions as an endogenous physiologically relevant mammalian RXR ligand.
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Affiliation(s)
- Ángel R de Lera
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IBIV, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310, Vigo, Spain.
| | - Wojciech Krezel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut de la Santé et de la Recherche Médicale, U964, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7104, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, 67404, Illkirch, France
| | - Ralph Rühl
- Paprika Bioanalytics BT, Debrecen, Hungary.,MTA-DE, Public Health Research Group of the Hungarian Academy of Sciences, Faculty of Public Health, University of Debrecen, Hungary
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Retinoid X Receptor Agonists Upregulate Genes Responsible for the Biosynthesis of All-Trans-Retinoic Acid in Human Epidermis. PLoS One 2016; 11:e0153556. [PMID: 27078158 PMCID: PMC4831765 DOI: 10.1371/journal.pone.0153556] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 03/31/2016] [Indexed: 11/26/2022] Open
Abstract
UAB30 is an RXR selective agonist that has been shown to have potential cancer chemopreventive properties. Due to high efficacy and low toxicity, it is currently being evaluated in human Phase I clinical trials by the National Cancer Institute. While UAB30 shows promise as a low toxicity chemopreventive drug, the mechanism of its action is not well understood. In this study, we investigated the effects of UAB30 on gene expression in human organotypic skin raft cultures and mouse epidermis. The results of this study indicate that treatment with UAB30 results in upregulation of genes responsible for the uptake and metabolism of all-trans-retinol to all-trans-retinoic acid (ATRA), the natural agonist of RAR nuclear receptors. Consistent with the increased expression of these genes, the steady-state levels of ATRA are elevated in human skin rafts. In ultraviolet B (UVB) irradiated mouse skin, the expression of ATRA target genes is found to be reduced. A reduced expression of ATRA sensitive genes is also observed in epidermis of mouse models of UVB-induced squamous cell carcinoma and basal cell carcinomas. However, treatment of mouse skin with UAB30 prior to UVB irradiation prevents the UVB-induced decrease in expression of some of the ATRA-responsive genes. Considering its positive effects on ATRA signaling in the epidermis and its low toxicity, UAB30 could be used as a chemoprophylactic agent in the treatment of non-melanoma skin cancer, particularly in organ transplant recipients and other high risk populations.
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Parodi PW. Cooperative action of bioactive components in milk fat with PPARs may explain its anti-diabetogenic properties. Med Hypotheses 2016; 89:1-7. [DOI: 10.1016/j.mehy.2015.12.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 12/30/2015] [Indexed: 01/04/2023]
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Rühl R, Krzyżosiak A, Niewiadomska-Cimicka A, Rochel N, Szeles L, Vaz B, Wietrzych-Schindler M, Álvarez S, Szklenar M, Nagy L, de Lera AR, Krężel W. 9-cis-13,14-Dihydroretinoic Acid Is an Endogenous Retinoid Acting as RXR Ligand in Mice. PLoS Genet 2015; 11:e1005213. [PMID: 26030625 PMCID: PMC4451509 DOI: 10.1371/journal.pgen.1005213] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/13/2015] [Indexed: 01/08/2023] Open
Abstract
The retinoid X receptors (RXRs) are ligand-activated transcription factors which heterodimerize with a number of nuclear hormone receptors, thereby controlling a variety of (patho)-physiological processes. Although synthetic RXR ligands are developed for the treatment of various diseases, endogenous ligand(s) for these receptors have not been conclusively identified. We show here that mice lacking cellular retinol binding protein (Rbp1-/-) display memory deficits reflecting compromised RXR signaling. Using HPLC-MS and chemical synthesis we identified in Rbp1-/- mice reduced levels of 9-cis-13,14-dihydroretinoic acid (9CDHRA), which acts as an RXR ligand since it binds and transactivates RXR in various assays. 9CDHRA rescues the Rbp1-/- phenotype similarly to a synthetic RXR ligand and displays similar transcriptional activity in cultured human dendritic cells. High endogenous levels of 9CDHRA in mice indicate physiological relevance of these data and that 9CDHRA acts as an endogenous RXR ligand. Daily nutrition, in addition to being a source of energy, contains micronutrients, a class of nutrients including vitamins which are essential for life and which act by orchestrating a vast number of developmental and physiological processes. During metabolism, micronutrients are frequently transformed into their bioactive forms. Nuclear hormone receptors are a family of proteins functioning as ligand-regulated transcription factors which can sense such bioactive molecules and translate those signals into transcriptional, adaptive responses. Retinoid X receptors occupy a central place in this signaling as they directly interact, and thereby control, activities of several nuclear hormone receptors. We report here the identification of a novel bioactive form of vitamin A, which is the first endogenous form of this vitamin capable to bind and activate retinoid X receptors. Accordingly, we show that this single molecule displays biological activity similar to synthetic agonists of retinoid X receptors and coordinates transcriptional activities of several nuclear receptor signaling pathways. Those findings may have immediate biomedical implications, as retinoid X receptors are implicated in the control of a number of physiological functions and their pathology.
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Affiliation(s)
- Ralph Rühl
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Debrecen, Hungary
- Paprika Bioanalytics BT, Debrecen, Hungary
- * E-mail: (RR); (ARdL); (WK)
| | - Agnieszka Krzyżosiak
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Inserm, U 964
- CNRS UMR 7104, Université de Strasbourg, Strasbourg, France
| | - Anna Niewiadomska-Cimicka
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Inserm, U 964
- CNRS UMR 7104, Université de Strasbourg, Strasbourg, France
| | - Natacha Rochel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Inserm, U 964
- CNRS UMR 7104, Université de Strasbourg, Strasbourg, France
| | - Lajos Szeles
- DE-MTA “Lendület” Immunogenomics Research Group, University of Debrecen, Debrecen, Hungary
| | - Belén Vaz
- Departamento de Química Orgánica and CINBIO, Facultad de Química, Universidade de Vigo, Vigo, Spain
- Instituto de Investigación Biomédica de Vigo (IBIV), Vigo, Spain
| | - Marta Wietrzych-Schindler
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Inserm, U 964
- CNRS UMR 7104, Université de Strasbourg, Strasbourg, France
| | - Susana Álvarez
- Departamento de Química Orgánica and CINBIO, Facultad de Química, Universidade de Vigo, Vigo, Spain
- Instituto de Investigación Biomédica de Vigo (IBIV), Vigo, Spain
| | | | - Laszlo Nagy
- DE-MTA “Lendület” Immunogenomics Research Group, University of Debrecen, Debrecen, Hungary
| | - Angel R. de Lera
- Departamento de Química Orgánica and CINBIO, Facultad de Química, Universidade de Vigo, Vigo, Spain
- Instituto de Investigación Biomédica de Vigo (IBIV), Vigo, Spain
- * E-mail: (RR); (ARdL); (WK)
| | - Wojciech Krężel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Inserm, U 964
- CNRS UMR 7104, Université de Strasbourg, Strasbourg, France
- * E-mail: (RR); (ARdL); (WK)
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Antiageing Mechanisms of a Standardized Supercritical CO 2 Preparation of Black Jack (Bidens pilosa L.) in Human Fibroblasts and Skin Fragments. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:280529. [PMID: 25883669 PMCID: PMC4391488 DOI: 10.1155/2015/280529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/23/2015] [Accepted: 03/15/2015] [Indexed: 12/26/2022]
Abstract
The use of topical retinoids to treat skin disorders and ageing can induce local reactions, while oral retinoids are potent teratogens and produce several unwanted effects. This way, efforts to explore complementary care resources should be supported. Based on this, we evaluate the antiageing effects of a supercritical CO2 extract from Bidens pilosa L. (BPE-CO2A) containing a standardized multicomponent mixture of phytol, linolenic, palmitic, linoleic, and oleic acids. BPE-CO2A was assessed for its effects on human dermal fibroblasts (TGF-β1 and FGF levels using ELISA; collagen, elastin, and glycosaminoglycan by colorimetric assays, and mRNA expression of RXR, RAR, and EGFr by qRT-PCR) and human skin fragments (RAR, RXR, collagen, elastin, and glycosaminoglycan by immunohistochemical analysis). Levels of extracellular matrix elements, TGF-β1 and FGF, and EGFr gene expression were significantly increased by BPE-CO2A. The modulation of RXR and RAR was positively demonstrated after the treatment with BPE-CO2A or phytol, a component of BPE-CO2A. The effects produced by BPE-CO2A were similar to or better than those produced by retinol and retinoic acid. The ability to stimulate extracellular matrix elements, increase growth factors, and modulate retinoid and rexinoid receptors provides a basis for the development of preparation containing BPE-CO2A as an antiageing/skin-repair agent.
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Li L, Bonneton F, Chen XY, Laudet V. Botanical compounds and their regulation of nuclear receptor action: the case of traditional Chinese medicine. Mol Cell Endocrinol 2015; 401:221-37. [PMID: 25449417 DOI: 10.1016/j.mce.2014.10.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 10/23/2014] [Accepted: 10/31/2014] [Indexed: 02/06/2023]
Abstract
Nuclear receptors (NRs) are major pharmacological targets that allow an access to the mechanisms controlling gene regulation. As such, some NRs were identified as biological targets of active compounds contained in herbal remedies found in traditional medicines. We aim here to review this expanding literature by focusing on the informative articles regarding the mechanisms of action of traditional Chinese medicines (TCMs). We exemplified well-characterized TCM action mediated by NR such as steroid receptors (ER, GR, AR), metabolic receptors (PPAR, LXR, FXR, PXR, CAR) and RXR. We also provided, when possible, examples from other traditional medicines. From these, we draw a parallel between TCMs and phytoestrogens or endocrine disrupting chemicals also acting via NR. We define common principle of action and highlight the potential and limits of those compounds. TCMs, by finely tuning physiological reactions in positive and negative manners, could act, in a subtle but efficient way, on NR sensors and their transcriptional network.
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Affiliation(s)
- Ling Li
- Institut de Génomique Fonctionnelle de Lyon; Université de Lyon; Université Lyon 1; CNRS UMR 5242; Ecole Normale Supérieure de Lyon, France.; School of Ecological and Environmental Science, East China Normal University, Shanghai, China
| | - François Bonneton
- Institut de Génomique Fonctionnelle de Lyon; Université de Lyon; Université Lyon 1; CNRS UMR 5242; Ecole Normale Supérieure de Lyon, France
| | - Xiao Yong Chen
- School of Ecological and Environmental Science, East China Normal University, Shanghai, China
| | - Vincent Laudet
- Institut de Génomique Fonctionnelle de Lyon; Université de Lyon; Université Lyon 1; CNRS UMR 5242; Ecole Normale Supérieure de Lyon, France..
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23
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Kataria Y, Wright M, Deaton RJ, Rueter EE, Rybicki BA, Moser AB, Ananthanrayanan V, Gann PH. Dietary influences on tissue concentrations of phytanic acid and AMACR expression in the benign human prostate. Prostate 2015; 75:200-10. [PMID: 25307752 PMCID: PMC4778716 DOI: 10.1002/pros.22905] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 08/26/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND Alpha-methylacyl-CoA racemase (AMACR) is an enzyme involved in fatty acid metabolism that is markedly over-expressed in virtually all prostate cancers (PCa), relative to benign tissue. One of AMACR's primary substrates, phytanic acid, is derived predominately from red meat and dairy product consumption. Epidemiological evidence suggests links between dairy/red meat intake, as well as phytanic acid levels, and elevated PCa risk. This study investigates the relationships among dietary intake, serum and tissue concentrations of phytanic acid, and AMACR expression (mRNA and protein) in the histologically benign human prostate. METHODS Men undergoing radical prostatectomy for the treatment of localized disease provided a food frequency questionnaire (n = 68), fasting blood (n = 35), benign fresh frozen prostate tissue (n = 26), and formalin-fixed paraffin-embedded (FFPE) sections (n = 67). Serum and tissue phytanic acid concentrations were obtained by gas chromatography-mass spectrometry. We extracted RNA from epithelial cells using laser capture microdissection and quantified mRNA expression of AMACR and other genes involved in the peroxisomal phytanic acid metabolism pathway via qRT-PCR. Immunohistochemistry for AMACR was performed on FFPE sections and subsequently quantified via digital image analysis. Associations between diet, serum, and tissue phytanic acid levels, as well as AMACR and other gene expression levels were assessed by partial Spearman correlation coefficients. RESULTS High-fat dairy intake was the strongest predictor of circulating phytanic acid concentrations (r = 0.35, P = 0.04). Tissue phytanic acid concentrations were not associated with any dietary sources and were only weakly correlated with serum levels (r = 0.29, P = 0.15). AMACR gene expression was not associated with serum phytanic acid (r = 0.13, P = 0.47), prostatic phytanic acid concentrations (r = 0.03, P = 0.88), or AMACR protein expression (r = -0.16, P = 0.20). CONCLUSIONS Our data underscore the complexity of the relationship between AMACR and its substrates and do not support the unifying hypothesis that excess levels of dietary phytanic acid are responsible for both the overexpression of AMACR in prostate cancer and the potential association between PCa risk and intake of dairy foods and red meat.
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Affiliation(s)
- Yachana Kataria
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | | | - Ryan J. Deaton
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Erika Enk Rueter
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Benjamin A. Rybicki
- Department of Public Health Sciences, Henry Ford Health Systems, Detroit, Michigan
| | - Ann B. Moser
- Peroxisomal Diseases Lab, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | | | - Peter H. Gann
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- Correspondence to: Peter H. Gann, MD, ScD, Department of Pathology (MC 847), College of Medicine, 840 S. Wood Street, Chicago, IL 60612.
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Gutierrez-Mazariegos J, Schubert M, Laudet V. Evolution of retinoic acid receptors and retinoic acid signaling. Subcell Biochem 2014; 70:55-73. [PMID: 24962881 DOI: 10.1007/978-94-017-9050-5_4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Retinoic acid (RA) is a vitamin A-derived morphogen controlling important developmental processes in vertebrates, and more generally in chordates, including axial patterning and tissue formation and differentiation. In the embryo, endogenous RA levels are controlled by RA synthesizing and degrading enzymes and the RA signal is transduced by two retinoid receptors: the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). Both RAR and RXR are members of the nuclear receptor superfamily of ligand-activated transcription factors and mainly act as heterodimers to activate the transcription of target genes in the presence of their ligand, all-trans RA. This signaling pathway was long thought to be a chordate innovation, however, recent findings of gene homologs involved in RA signaling in the genomes of a wide variety of non-chordate animals, including ambulacrarians (sea urchins and acorn worms) and lophotrochozoans (annelids and mollusks), challenged this traditional view and suggested that the RA signaling pathway might have a more ancient evolutionary origin than previously thought. In this chapter, we discuss the evolutionary history of the RA signaling pathway, and more particularly of the RARs, which might have experienced independent gene losses and duplications in different animal lineages. In sum, the available data reveal novel insights into the origin of the RA signaling pathway as well as into the evolutionary history of the RARs.
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Affiliation(s)
- Juliana Gutierrez-Mazariegos
- Molecular Zoology Team, Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS, INRA, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364, Lyon Cedex 07, France,
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25
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Inoue M, Tanabe H, Nakashima KI, Ishida Y, Kotani H. Rexinoids isolated from Sophora tonkinensis with a gene expression profile distinct from the synthetic rexinoid bexarotene. JOURNAL OF NATURAL PRODUCTS 2014; 77:1670-1677. [PMID: 24959987 DOI: 10.1021/np5002016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The retinoid X receptor (RXR) plays a critical role in transcriptional regulation via formation of an RXR homodimer or heterodimers with partner nuclear receptors. Despite the numerous beneficial effects, only a limited number of naturally occurring RXR agonists are known. In this report, two prenylated flavanones (1 and 2) isolated from Sophora tonkinensis were identified as new rexinoids that preferentially activated RXRs, relative to the retinoic acid receptor. The activities of 1 and 2 were the most potent among naturally occurring rexinoids, yet 2 orders of magnitude lower than the synthetic rexinoid bexarotene. Compounds 1 and 2 activated particular RXR heterodimers in a manner similar to bexarotene. A microarray assay followed by quantitative real-time polymerase chain reaction analyses on RNAs isolated from C2C12 myotubes treated with 1 or 2 demonstrated that they significantly increased mRNA levels of lipoprotein lipase, angiopoietin-like protein 4, and heme oxygenase-1. In contrast, bexarotene preferentially potentiated transcription of genes involved in lipogenesis and lipid metabolism such as sterol regulatory element-binding protein-1, fatty acid synthase, and apolipoprotein D by a liver X receptor agonist. In this study, we have demonstrated that two newly identified naturally occurring rexinoids, 1 and 2, possess properties different from bexarotene.
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Affiliation(s)
- Makoto Inoue
- Department of Pharmacology of Natural Compounds, Graduate School of Pharmaceutical Sciences, Aichi Gakuin University , 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan
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Menon GK, Orsó E, Aslanidis C, Crumrine D, Schmitz G, Elias PM. Ultrastructure of skin from Refsum disease with emphasis on epidermal lamellar bodies and stratum corneum barrier lipid organization. Arch Dermatol Res 2014; 306:731-7. [PMID: 24920240 DOI: 10.1007/s00403-014-1478-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/14/2014] [Accepted: 05/29/2014] [Indexed: 10/25/2022]
Abstract
Classic Refsum disease (RD) is a rare, autosomal recessively-inherited disorder of peroxisome metabolism due to a defect in the initial step in the alpha oxidation of phytanic acid (PA), a C16 saturated fatty acid with four methyl side groups, which accumulates in plasma and lipid enriched tissues (please see van den Brink and Wanders, Cell Mol Life Sci 63:1752-1765, 2006). It has been proposed that the disease complex in RD is in part due to the high affinity of phytanic acid for retinoid X receptors and peroxisome proliferator-activated receptors. Structurally, epidermal hyperplasia, increased numbers of cornified cell layers, presence of cells with lipid droplets in stratum basale and reduction of granular layer to a single layer have been reported by Blanchet-Bardon et al. (The ichthyoses, SP Medical & Scientific Books, New York, pp 65-69, 1978). However, lamellar body (LB) density and secretion were reportedly normal. We recently examined biopsies from four unrelated patients, using both OsO4 and RuO4 post-fixation to evaluate the barrier lipid structural organization. Although lamellar body density appeared normal, individual organelles often had distorted shape, or had non-lamellar domains interspersed with lamellar structures. Some of the organelles seemed to lack lamellar contents altogether, showing instead uniformly electron-dense contents. In addition, we also observed mitochondrial abnormalities in the nucleated epidermis. Stratum granulosum-stratum corneum junctions also showed co-existence of non-lamellar and lamellar domains, indicative of lipid phase separation. Also, partial detachment or complete absence of corneocyte lipid envelopes (CLE) was seen in the stratum corneum of all RD patients. In conclusion, abnormal LB contents, resulting in defective lamellar bilayers, as well as reduced CLEs, likely lead to impaired barrier function in RD.
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Affiliation(s)
- G K Menon
- Global Research and Development, Ashland, Inc., Bridgewater, NJ, USA
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Abstract
INTRODUCTION Retinoid X receptors (RXRs) are nuclear receptors that act as ligand-dependent transcription factors. RXRs function as homodimers or as heterodimers with other nuclear receptors, such as retinoic acid receptors, PPARs, liver X receptors, farnesoid X receptor, vitamin D receptor or thyroid hormone receptors. RXR ligands (agonists or antagonists) show various physiological effects, depending on their partner receptors. RXR agonist bexarotene (Targretin®) is used for the treatment of cutaneous T-cell lymphoma in clinical practice. RXR agonists were also reported to be useful for treatment of type 2 diabetes, autoimmune disease and Alzheimer's disease. RXR antagonists were also reported to be effective in type 2 diabetes treatment. AREAS COVERED Here patent applications (2007 - 2013) concerning RXR ligands are summarized, and the usefulness of RXR ligands as pharmaceutical agents is discussed. EXPERT OPINION RXR agonists show a wide variety of biological effects. However, they cause serious side effects, such as blood triglyceride elevation, hypothyroidism and others. Thus, for clinical application of RXR agonists, abrogation of these side effects is required. RXR heterodimer-selective agonists and RXR partial agonists exhibiting desired effects without side effects are expected to find clinical application.
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Affiliation(s)
- Shoya Yamada
- Okayama University Graduate School of Medicine, Division of Pharmaceutical Sciences, Dentistry and Pharmaceutical Sciences , 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530 , Japan +81 086 251 7963 ; +81 086 251 7963 ;
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Abstract
Retinoid X Receptors (RXR) were initially identified as nuclear receptors binding with stereo-selectivity the vitamin A derivative 9-cis retinoic acid, although the relevance of this molecule as endogenous activator of RXRs is still elusive. Importantly, within the nuclear receptor superfamily, RXRs occupy a peculiar place, as they are obligatory partners for a number of other nuclear receptors, thus integrating the corresponding signaling pathways. In this chapter, we describe the structural features allowing RXR to form homo- and heterodimers, and the functional consequences of this unique ability. Furthermore, we discuss the importance of studying RXR activity at a genome-wide level in order to comprehensively address the biological implications of their action that is fundamental to understand to what extent RXRs could be exploited as new therapeutic targets.
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Affiliation(s)
- Federica Gilardi
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015, Lausanne, Switzerland,
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Kiss M, Czimmerer Z, Nagy L. The role of lipid-activated nuclear receptors in shaping macrophage and dendritic cell function: From physiology to pathology. J Allergy Clin Immunol 2013; 132:264-86. [PMID: 23905916 DOI: 10.1016/j.jaci.2013.05.044] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/16/2013] [Accepted: 05/30/2013] [Indexed: 02/06/2023]
Abstract
Nuclear receptors are ligand-activated transcription factors linking lipid signaling to the expression of the genome. There is increasing appreciation of the involvement of this receptor network in the metabolic programming of macrophages and dendritic cells (DCs), essential members of the innate immune system. In this review we focus on the role of retinoid X receptor, retinoic acid receptor, peroxisome proliferator-associated receptor γ, liver X receptor, and vitamin D receptor in shaping the immune and metabolic functions of macrophages and DCs. We also provide an overview of the contribution of macrophage- and DC-expressed nuclear receptors to various immunopathologic conditions, such as rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, asthma, and some others. We suggest that systematic analyses of the roles of these receptors and their activating lipid ligands in immunopathologies combined with complementary and focused translational and clinical research will be crucial for the development of new therapies using the many molecules available to target nuclear receptors.
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Affiliation(s)
- Mate Kiss
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary
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Sarang Z, Garabuczi É, Joós G, Kiss B, Tóth K, Rühl R, Szondy Z. Macrophages engulfing apoptotic thymocytes produce retinoids to promote selection, differentiation, removal and replacement of double positive thymocytes. Immunobiology 2013; 218:1354-60. [PMID: 23932496 DOI: 10.1016/j.imbio.2013.06.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/04/2013] [Accepted: 06/17/2013] [Indexed: 11/30/2022]
Abstract
The thymus provides the microenvironment in which thymocytes develop into mature T-cells, and interactions with thymic stromal cells are thought to provide the necessary signals for thymocyte maturation. Recognition of self-MHC by T-cells is a basic requirement for mature T-cell functions, and those thymocytes that do not recognize or respond too strongly to the peptide-loaded self-MHC molecules found in the thymus undergo apoptosis. As a result, 95% of the thymocytes produced will die and be subsequently cleared by macrophages. This review describes a complex crosstalk between developing thymocytes and engulfing macrophages which is mediated by retinoids produced by engulfing macrophages. The interaction results in the harmonization of the rate of cell death of dying double positive cells with their clearance and replacement, and in promotion of the differentiation of the selected cells in the thymus.
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Affiliation(s)
- Zsolt Sarang
- Section of Dental Biochemistry, Department of Biochemistry and Molecular Biology, Research Center of Molecular Medicine, University of Debrecen, Nagyerdei krt. 98, 4012 Debrecen, Hungary
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Werner LB, Hellgren LI, Raff M, Jensen SK, Petersen RA, Drachmann T, Tholstrup T. Effects of butter from mountain-pasture grazing cows on risk markers of the metabolic syndrome compared with conventional Danish butter: a randomized controlled study. Lipids Health Dis 2013; 12:99. [PMID: 23842081 PMCID: PMC3720277 DOI: 10.1186/1476-511x-12-99] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/28/2013] [Indexed: 11/27/2022] Open
Abstract
Background There is considerable interest in dairy products from low-input systems, such as mountain-pasture grazing cows, because these products are believed to be healthier than products from high-input conventional systems. This may be due to a higher content of bioactive components, such as phytanic acid, a PPAR-agonist derived from chlorophyll. However, the effects of such products on human health have been poorly investigated. Objective To compare the effect of milk-fat from mountain-pasture grazing cows (G) and conventionally fed cows (C) on risk markers of the metabolic syndrome. Design In a double-blind, randomized, 12-week, parallel intervention study, 38 healthy subjects replaced part of their habitual dietary fat intake with 39 g fat from test butter made from milk from mountain-pasture grazing cows or from cows fed conventional winter fodder. Glucose-tolerance and circulating risk markers were analysed before and after the intervention. Results No differences in blood lipids, lipoproteins, hsCRP, insulin, glucose or glucose-tolerance were observed. Interestingly, strong correlations between phytanic acid at baseline and total (P<0.0001) and LDL cholesterol (P=0.0001) were observed. Conclusions Lack of effects on blood lipids and inflammation indicates that dairy products from mountain-pasture grazing cows are not healthier than products from high-input conventional systems. Considering the strong correlation between LDL cholesterol and phytanic acid at baseline, it may be suggested that phytanic acid increases total and LDL cholesterol. Trial registration ClinicalTrials.gov, NCT01343589
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Affiliation(s)
- Louise B Werner
- Department of Nutrition, Exercise and Sports, Faculty of Sciences, University of Copenhagen, Frederiksberg 1958, Denmark.
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Che BN, Oksbjerg N, Hellgren LI, Nielsen JH, Young JF. Phytanic acid stimulates glucose uptake in a model of skeletal muscles, the primary porcine myotubes. Lipids Health Dis 2013; 12:14. [PMID: 23398851 PMCID: PMC3606424 DOI: 10.1186/1476-511x-12-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 01/31/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phytanic acid (PA) is a chlorophyll metabolite with potentials in regulating glucose metabolism, as it is a natural ligand of the peroxisome proliferator-activated receptor (PPAR) that is known to regulate hepatic glucose homeostasis. This study aimed to establish primary porcine myotubes as a model for measuring glucose uptake and glycogen synthesis, and to examine the impact of physiological amounts of PA on glucose uptake and glycogen synthesis either alone or in combination with insulin. METHODS Porcine satellite cells were cultured into differentiated myotubes and tritiated 2-deoxyglucose (2-DOG) was used to measure glucose uptake, in relation to PA and 2-DOG exposure times and also in relation to PA and insulin concentrations. The MIXED procedure model of SAS was used for statistical analysis of data. RESULTS PA increased glucose uptake by approximately 35%, and the presence of insulin further increased the uptake, but this further increase in uptake was non- additive and less pronounced at high insulin concentrations. There was no effect of PA alone on glycogen synthesis, while the insulin stimulation of glycogen was increased by 20% in the presence of PA. PA neither stimulated glucose uptake nor glycogen synthesis in insulin-resistant myotubes generated by excess glucose exposure. CONCLUSIONS Primary porcine myotubes were established as a model of skeletal muscles for measuring glucose uptake and glycogen synthesis, and we showed that PA can play a role in stimulating glucose uptake at no or inadequate insulin concentrations.
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Affiliation(s)
- Brita N Che
- Department of Food Science, Aarhus University, Blichers Allé 20, Tjele, 8830, Denmark
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Hurst RJM, Else KJ. Retinoic acid signalling in gastrointestinal parasite infections: lessons from mouse models. Parasite Immunol 2012; 34:351-9. [PMID: 22443219 PMCID: PMC3485670 DOI: 10.1111/j.1365-3024.2012.01364.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Retinoic acid or vitamin A is important for an extensive range of biological processes, including immunomodulatory functions, however, its role in gastrointestinal parasite infections is not yet clear. Despite this, parasite infected individuals are often supplemented with vitamin A, given the co-localised prevalence of parasitic infections and vitamin deficiencies. Therefore, it is important to understand the impact of this vitamin on the immune responses to gastrointestinal parasites. Here, we review data regarding the role of retinoic acid signalling in mouse models of intestinal nematode infection, with a view to understanding better the practice of giving vitamin A supplements to worm-infected people.
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Affiliation(s)
- R J M Hurst
- The University of Manchester, Manchester M13 9PT, UK.
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Abstract
INTRODUCTION Retinoid X receptors (subtypes RXRα or NR2B1, RXRβ or NR2B2 and RXRγ or NR2B3, which originate from three distinct genes) are promiscuous partners with heterodimeric associations to other members of the Nuclear Receptor (NR) superfamily. Some of the heterodimers are "permissive" and transcriptionally active in the presence of either an RXR ligand ("rexinoid") or a NR partner ligand, whereas others are "non-permissive" and unresponsive to rexinoids alone. In rodent models, rexinoids and partner agonists (mainly PPARγ, LXR, FXR) produce beneficial effects on insulin sensitization, diabetes and obesity, but secondary effects have also been noted, such as a raise in tryglyceride levels, supression of the thyroid hormone axis and induction of hepatomegaly. AREAS COVERED The authors review recent advances in rexinoid design, including further optimization of known scaffolds, and the discovery of novel RXR modulators by virtual ligand screening or from bioactive natural products. The understanding of rexinoid functions in permissive and non-permissive heterodimers is firmly based on structural knowledge. By strenghtening or disrupting the interaction surface with coregulators rexinoids exert agonist or (partial) antagonist activities. The activity state of the heterodimer can also be fine-tuned by the cellular context and the nature of coregulators. EXPERT OPINION The synthetic chemistry toolbox has provided a panel of agonists, partial (ant)agonists and/or heterodimer-selective rexinoids starting from existing, naturally occurring or serendipitously discovered scaffolds. These compounds have an unexplored therapeutic potential that might overcome some of the current limitations of rexinoids in therapy, such as hypertriglyceridemia.
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Affiliation(s)
- Belén Vaz
- Departamento de Química Orgánica, Facultad de Química and Centro de Investigaciones Biomédicas (CINBIO), Universidade de Vigo, Vigo, Spain
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The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease. Eur J Nutr 2012; 52:1-24. [PMID: 22810464 DOI: 10.1007/s00394-012-0418-1] [Citation(s) in RCA: 273] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 07/02/2012] [Indexed: 12/14/2022]
Abstract
PURPOSE To comprehensively review the data on the relationship between the consumption of dairy fat and high-fat dairy foods, obesity, and cardiometabolic disease. METHODS We have conducted a systematic literature review of observational studies on the relationship between dairy fat and high-fat dairy foods, obesity, and cardiometabolic disease. We have integrated these findings with data from controlled studies showing effects of several minor dairy fatty acids on adiposity and cardiometabolic risk factors, and data on how bovine feeding practices influence the composition of dairy fat. RESULTS In 11 of 16 studies, high-fat dairy intake was inversely associated with measures of adiposity. Studies examining the relationship between high-fat dairy consumption and metabolic health reported either an inverse or no association. Studies investigating the connection between high-fat dairy intake and diabetes or cardiovascular disease incidence were inconsistent. We discuss factors that may have contributed to the variability between studies, including differences in (1) the potential for residual confounding; (2) the types of high-fat dairy foods consumed; and (3) bovine feeding practices (pasture- vs. grain-based) known to influence the composition of dairy fat. CONCLUSIONS The observational evidence does not support the hypothesis that dairy fat or high-fat dairy foods contribute to obesity or cardiometabolic risk, and suggests that high-fat dairy consumption within typical dietary patterns is inversely associated with obesity risk. Although not conclusive, these findings may provide a rationale for future research into the bioactive properties of dairy fat and the impact of bovine feeding practices on the health effects of dairy fat.
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Nagy L, Szanto A, Szatmari I, Széles L. Nuclear hormone receptors enable macrophages and dendritic cells to sense their lipid environment and shape their immune response. Physiol Rev 2012; 92:739-89. [PMID: 22535896 DOI: 10.1152/physrev.00004.2011] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A key issue in the immune system is to generate specific cell types, often with opposing activities. The mechanisms of differentiation and subtype specification of immune cells such as macrophages and dendritic cells are critical to understand the regulatory principles and logic of the immune system. In addition to cytokines and pathogens, it is increasingly appreciated that lipid signaling also has a key role in differentiation and subtype specification. In this review we explore how intracellular lipid signaling via a set of transcription factors regulates cellular differentiation, subtype specification, and immune as well as metabolic homeostasis. We introduce macrophages and dendritic cells and then we focus on a group of transcription factors, nuclear receptors, which regulate gene expression upon receiving lipid signals. The receptors we cover are the ones with a recognized physiological function in these cell types and ones which heterodimerize with the retinoid X receptor. These are as follows: the receptor for a metabolite of vitamin A, retinoic acid: retinoic acid receptor (RAR), the vitamin D receptor (VDR), the fatty acid receptor: peroxisome proliferator-activated receptor γ (PPARγ), the oxysterol receptor liver X receptor (LXR), and their obligate heterodimeric partner, the retinoid X receptor (RXR). We discuss how they can get activated and how ligand is generated and eliminated in these cell types. We also explore how activation of a particular target gene contributes to biological functions and how the regulation of individual target genes adds up to the coordination of gene networks. It appears that RXR heterodimeric nuclear receptors provide these cells with a coordinated and interrelated network of transcriptional regulators for interpreting the lipid milieu and the metabolic changes to bring about gene expression changes leading to subtype and functional specification. We also show that these networks are implicated in various immune diseases and are amenable to therapeutic exploitation.
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Affiliation(s)
- Laszlo Nagy
- Department of Biochemistry and Molecular Biology, University of Debrecen, Medical and Health Science Center, Egyetem tér 1, Debrecen, Hungary.
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Vanden Heuvel JP. Nutrigenomics and Nutrigenetics of ω3 Polyunsaturated Fatty Acids. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 108:75-112. [DOI: 10.1016/b978-0-12-398397-8.00004-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Werner LB, Hellgren LI, Raff M, Jensen SK, Petersen RA, Drachmann T, Tholstrup T. Effect of dairy fat on plasma phytanic acid in healthy volunteers - a randomized controlled study. Lipids Health Dis 2011; 10:95. [PMID: 21663648 PMCID: PMC3127790 DOI: 10.1186/1476-511x-10-95] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 06/10/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phytanic acid produced in ruminants from chlorophyll may have preventive effects on the metabolic syndrome, partly due to its reported RXR and PPAR- α agonist activity. Milk from cows fed increased levels of green plant material, contains increased phytanic acid concentrations, but it is unknown to what extent minor increases in phytanic acid content in dairy fat leads to higher circulating levels of phytanic acid in plasma of the consumers. OBJECTIVE To investigate if cow feeding regimes affects concentration of plasma phytanic acid and risk markers of the metabolic syndrome in human. DESIGN In a double-blind, randomized, 4 wk, parallel intervention study 14 healthy young subjects were given 45 g milk fat/d from test butter and cheese with 0.24 wt% phytanic acid or a control diet with 0.13 wt% phytanic acid. Difference in phytanic acid was obtained by feeding roughage with low or high content of chlorophyll. RESULTS There tended to be a difference in plasma phytanic acid (P = 0.0730) concentration after the dietary intervention. Plasma phytanic acid increased significantly within both groups with the highest increase in control group (24%) compared to phytanic acid group (15%). There were no significant effects of phytanic acid on risk markers for the metabolic syndrome. CONCLUSIONS The results indicate that increased intake of dairy fat modify the plasma phytanic acid concentration, regardless of cows feeding regime and the minor difference in dietary phytanic acid. Whether the phytanic acid has potential to affects the risk markers of the metabolic syndrome in human still remain to be elucidated.
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Affiliation(s)
- Louise B Werner
- Department of Human Nutrition, Faculty of Life, University of Copenhagen, Frederiksberg 1958, Denmark.
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Kruska N, Reiser G. Phytanic acid and pristanic acid, branched-chain fatty acids associated with Refsum disease and other inherited peroxisomal disorders, mediate intracellular Ca2+ signaling through activation of free fatty acid receptor GPR40. Neurobiol Dis 2011; 43:465-72. [PMID: 21570468 DOI: 10.1016/j.nbd.2011.04.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/18/2011] [Accepted: 04/22/2011] [Indexed: 01/28/2023] Open
Abstract
The accumulation of the two branched-chain fatty acids phytanic acid and pristanic acid is known to play an important role in several diseases with peroxisomal impairment, like Refsum disease, Zellweger syndrome and α-methylacyl-CoA racemase deficiency. Recent studies elucidated that the toxic activity of phytanic acid and pristanic acid is mediated by multiple mitochondrial dysfunctions, generation of reactive oxygen species and Ca2+ deregulation via the InsP3-Ca2+ signaling pathway in glial cells. However, the exact signaling mechanism through which both fatty acids mediate toxicity is still under debate. Here, we studied the ability of phytanic acid and pristanic acid to activate the free fatty acid receptor GPR40, a G-protein-coupled receptor, which was described to be involved in the Ca2+ signaling of fatty acids. We treated HEK 293 cells expressing the GPR40 receptor with phytanic acid or pristanic acid. This resulted in a significant increase in the intracellular Ca2+ level, similar to the effect seen after treatment with the synthetic GPR40 agonist GW9508. Furthermore, we demonstrate that the GPR40 activation might be due to an interaction of the carboxylate moiety of fatty acids with the receptor. Our findings indicate that the phytanic acid- and pristanic acid-mediated Ca2+ deregulation can involve the activation of GPR40. Therefore, we suppose that activation of GPR40 might be part of the signaling cascade of the toxicity of phytanic and pristanic acids.
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Affiliation(s)
- Nicol Kruska
- Institut für Neurobiochemie, Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Leipziger Str. 44, D-39120 Magdeburg, Germany
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Modulation of RXR function through ligand design. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:57-69. [PMID: 21515403 DOI: 10.1016/j.bbalip.2011.04.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/06/2011] [Accepted: 04/07/2011] [Indexed: 12/22/2022]
Abstract
As the promiscuous partner of heterodimeric associations, retinoid X receptors (RXRs) play a key role within the Nuclear Receptor (NR) superfamily. Some of the heterodimers (PPAR/RXR, LXR/RXR, FXR/RXR) are "permissive" as they become transcriptionally active in the sole presence of either an RXR-selective ligand ("rexinoid") or a NR partner ligand. In contrast, "non-permissive" heterodimers (including RAR/RXR, VDR/RXR and TR/RXR) are unresponsive to rexinoids alone but these agonists superactivate transcription by synergizing with partner agonists. Despite their promiscuity in heterodimer formation and activation of multiple pathways, RXR is a target for drug discovery. Indeed, a rexinoid is used in the clinic for the treatment of cutaneous T-cell lymphoma. In addition to cancer RXR modulators hold therapeutical potential for the treatment of metabolic diseases. The modulation potential of the rexinoid (as agonist or antagonist ligand) is dictated by the precise conformation of the ligand-receptor complexes and the nature and extent of their interaction with co-regulators, which determine the specific physiological responses through transcription modulation of cognate gene networks. Notwithstanding the advances in this field, it is not yet possible to predict the correlation between ligand structure and physiological response. We will focus on this review on the modulation of PPARγ/RXR and LXR/RXR heterodimer activities by rexinoids. The genetic and pharmacological data from animal models of insulin resistance, diabetes and obesity demonstrate that RXR agonists and antagonists have promise as anti-obesity agents. However, the treatment with rexinoids raises triglycerides levels, suppresses the thyroid hormone axis, and induces hepatomegaly, which has complicated the development of these compounds as therapeutic agents for the treatment of type 2 diabetes and insulin resistance. The discovery of PPARγ/RXR and LXR/RXR heterodimer-selective rexinoids, which act differently than PPARγ or LXR agonists, might overcome some of these limitations.
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Histological evaluation of rat mammary tumours after treatment with retinoic acid analogues — phytol, TTNPB and vitamin D3 analogue seocalcitol. Biologia (Bratisl) 2011. [DOI: 10.2478/s11756-011-0024-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Watkins PA, Moser AB, Toomer CB, Steinberg SJ, Moser HW, Karaman MW, Ramaswamy K, Siegmund KD, Lee DR, Ely JJ, Ryder OA, Hacia JG. Identification of differences in human and great ape phytanic acid metabolism that could influence gene expression profiles and physiological functions. BMC PHYSIOLOGY 2010; 10:19. [PMID: 20932325 PMCID: PMC2964658 DOI: 10.1186/1472-6793-10-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 10/08/2010] [Indexed: 02/11/2023]
Abstract
Background It has been proposed that anatomical differences in human and great ape guts arose in response to species-specific diets and energy demands. To investigate functional genomic consequences of these differences, we compared their physiological levels of phytanic acid, a branched chain fatty acid that can be derived from the microbial degradation of chlorophyll in ruminant guts. Humans who accumulate large stores of phytanic acid commonly develop cerebellar ataxia, peripheral polyneuropathy, and retinitis pigmentosa in addition to other medical conditions. Furthermore, phytanic acid is an activator of the PPAR-alpha transcription factor that influences the expression of genes relevant to lipid metabolism. Results Despite their trace dietary phytanic acid intake, all great ape species had elevated red blood cell (RBC) phytanic acid levels relative to humans on diverse diets. Unlike humans, chimpanzees showed sexual dimorphism in RBC phytanic acid levels, which were higher in males relative to females. Cultured skin fibroblasts from all species had a robust capacity to degrade phytanic acid. We provide indirect evidence that great apes, in contrast to humans, derive significant amounts of phytanic acid from the hindgut fermentation of plant materials. This would represent a novel reduction of metabolic activity in humans relative to the great apes. Conclusion We identified differences in the physiological levels of phytanic acid in humans and great apes and propose this is causally related to their gut anatomies and microbiomes. Phytanic acid levels could contribute to cross-species and sex-specific differences in human and great ape transcriptomes, especially those related to lipid metabolism. Based on the medical conditions caused by phytanic acid accumulation, we suggest that differences in phytanic acid metabolism could influence the functions of human and great ape nervous, cardiovascular, and skeletal systems.
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Affiliation(s)
- Paul A Watkins
- Department ofNeurology, Johns Hopkins University School of Medicine, Hugo W Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA
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Széles L, Póliska S, Nagy G, Szatmari I, Szanto A, Pap A, Lindstedt M, Santegoets SJAM, Rühl R, Dezsö B, Nagy L. Research resource: transcriptome profiling of genes regulated by RXR and its permissive and nonpermissive partners in differentiating monocyte-derived dendritic cells. Mol Endocrinol 2010; 24:2218-31. [PMID: 20861222 PMCID: PMC3051201 DOI: 10.1210/me.2010-0215] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Retinoid X receptors (RXRs) are heterodimerization partners for many nuclear receptors and also act as homodimers. Heterodimers formed by RXR and a nonpermissive partner, e.g. retinoic acid receptor (RAR) and vitamin D receptor (VDR), can be activated only by the agonist of the partner receptor. In contrast, heterodimers that contain permissive partners, e.g. liver X receptor (LXR) and peroxisome proliferator-activated receptor (PPAR), can be activated by agonists for either the partner receptor or RXR, raising the possibility of pleiotropic RXR signaling. However, it is not known to what extent the receptor’s activation results in triggering mechanisms dependent or independent of permissive heterodimers. In this study, we systematically and quantitatively characterized all probable RXR-signaling pathways in differentiating human monocyte-derived dendritic cells (Mo-DCs). Using pharmacological, microarray and quantitative RT-PCR techniques, we identified and characterized gene sets regulated by RXR agonists (LG100268 and 9-cis retinoic acid) and agonists for LXRs, PPARs, RARα, and VDR. Our results demonstrated that permissiveness was partially impaired in Mo-DCs, because a large number of genes regulated by PPAR or LXR agonists was not affected by RXR-specific agonists or was regulated to a lesser extent. As expected, we found that RXR agonists regulated only small portions of RARα or VDR targets. Importantly, we could identify and characterize PPAR- and LXR-independent pathways in Mo-DCs most likely mediated by RXR homodimers. These data suggested that RXR signaling in Mo-DCs was mediated via multiple permissive heterodimers and also by mechanism(s) independent of permissive heterodimers, and it was controlled in a cell-type and gene-specific manner. This works reports the mapping of RXR mediated transcription in human dendritic cells and shows that it is through multiple permissive heterodimers and also via heterodimer-independent mechanisms.
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Affiliation(s)
- Lajos Széles
- Department of Biochemistry and Molecular Biology, Medical and Health Science Center, University of Debrecen, Egyetem Tér 1, H-4010 Debrecen, Hungary
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Abstract
Phytanic acid is a multibranched fatty acid with reported retinoid X receptor (RXR) and peroxisome proliferator-activated receptor-alpha (PPAR-alpha) agonist activity, which have been suggested to have preventive effects on metabolic dysfunctions. Serum level in man is strongly correlated to the intake of red meat and dairy products and the concentration in these products is strongly correlated to the chlorophyll content in the feed of the cattle. Available data suggest that phytanic acid is a natural agonist for RXR at physiological concentrations, while it is more likely that it is the metabolite pristanic acid, rather than phytanic acid itself, that acts as PPAR-alpha agonist. Animal studies show increased expression of genes involved in fatty acid oxidation, after intake of phytol, the metabolic precursor of phytanic acid, but it is at present not possible to deduce whether phytanic acid is useful in the prevention of ectopic lipid deposition. Phytanic acid is an efficient inducer of the expression of uncoupler protein 1 (UCP1). UCP1 is expressed in human skeletal muscles, were it might be important for the total energy balance. Therefore, phytanic acid may be able to stimulate energy dissipation in skeletal muscles. Phytanic acid levels in serum are associated with an increased risk of developing prostate cancer, but the available data do not support a general causal link between circulating phytanic acid and prostate cancer risk. However, certain individuals, with specific single-nucleotide polymorphisms in the gene for the enzyme alpha-methylacyl-CoA racemase, might be susceptible to raised phytanic acid levels.
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Affiliation(s)
- Lars I Hellgren
- Center for Biological Sequence Analysis and Center for Advanced Food Studies, Department of System Biology, Technical University of Denmark, Lyngby, Denmark.
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Abstract
The endothelium is critical for the maintenance of a proper vessel function. Disturbances of endothelial function, called endothelial dysfunction, have serious implications, and lead to the development of atherosclerosis. It is well established that the risk for atherosclerosis development is influenced by nutritional factors such as the intake of certain fatty acids. Due to the fundamental role of the endothelium for atherosclerosis development, it is, therefore, likely that fatty acids directly influence the function of endothelial cells. The present review aims to explain the divergent effects of different types of fatty acids on cardiovascular disease risk by summarizing in vitro-data on the effects of fatty acids on (1) important signalling pathways involved in the modulation of endothelial cell function, and (2) endothelial cell functional properties, namely vasoactive mediator release and mononuclear cell recruitment, both of which are typically dysregulated during endothelial dysfunction.
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Affiliation(s)
- Robert Ringseis
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-Universität Giessen, Giessen, Germany
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Peroxisomes, lipid metabolism and lipotoxicity. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:272-80. [DOI: 10.1016/j.bbalip.2010.01.001] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/07/2010] [Accepted: 01/07/2010] [Indexed: 12/26/2022]
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Dawson MI, Ye M, Cao X, Farhana L, Hu QY, Zhao Y, Xu LP, Kiselyuk A, Correa RG, Yang L, Hou T, Reed JC, Itkin-Ansari P, Levine F, Sanner MF, Fontana JA, Zhang XK. Derivation of a retinoid X receptor scaffold from peroxisome proliferator-activated receptor gamma ligand 1-Di(1H-indol-3-yl)methyl-4-trifluoromethylbenzene. ChemMedChem 2009; 4:1106-19. [PMID: 19378296 DOI: 10.1002/cmdc.200800447] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PPARgamma agonist DIM-Ph-4-CF(3), a template for RXRalpha agonist (E)-3-[5-di(1-methyl-1H-indol-3-yl)methyl-2-thienyl] acrylic acid: DIM-Ph-CF(3) is reported to inhibit cancer growth independent of PPARgamma and to interact with NR4A1. As both receptors dimerize with RXR, and natural PPARgamma ligands activate RXR, DIM-Ph-4-CF(3) was investigated as an RXR ligand. It displaces 9-cis-retinoic acid from RXRalpha but does not activate RXRalpha. Structure-based direct design led to an RXRalpha agonist.1-Di(1H-indol-3-yl)methyl-4-trifluoromethylbenzene (DIM-Ph-4-CF(3)) is reported to inhibit cancer cell growth and to act as a transcriptional agonist of peroxisome proliferator-activated receptor gamma (PPARgamma) and nuclear receptor 4A subfamily member 1 (NR4A1). In addition, DIM-Ph-4-CF(3) exerts anticancer effects independent of these receptors because PPARgamma antagonists do not block its inhibition of cell growth, and the small pocket in the NR4A1 crystal structure suggests no ligand can bind. Because PPARgamma and NR4A1 heterodimerize with retinoid X receptor (RXR), and several PPARgamma ligands transcriptionally activate RXR, DIM-Ph-4-CF(3) was investigated as an RXR ligand. DIM-Ph-4-CF(3) displaces 9-cis-retinoic acid from RXRalpha but does not transactivate RXRalpha. Structure-based design using DIM-Ph-4-CF(3) as a template led to the RXRalpha transcriptional agonist (E)-3-[5-di(1-methyl-1H-indol-3-yl)methyl-2-thienyl]acrylic acid. Its docked pose in the RXRalpha ligand binding domain suggests that binding is stabilized by interactions of its carboxylate group with arginine 316, its indoles with cysteines 269 and 432, and its 1-methyl groups with hydrophobic residues lining the binding pocket. As is expected of a selective activator of RXRalpha, but not of RARs and PPARgamma, this RXRalpha agonist, unlike DIM-Ph-4-CF(3), does not appreciably decrease cancer cell growth or induce apoptosis at pharmacologically relevant concentrations.
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Affiliation(s)
- Marcia I Dawson
- Cancer Center, Burnham Institute for Medical Research, 10901 North Torrey Pines Rd., La Jolla, CA 92037, USA.
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Abstract
The molting process in arthropods is regulated by steroid hormones acting via nuclear receptor proteins. The most common molting hormone is the ecdysteroid, 20-hydroxyecdysone. The receptors of 20-hydroxyecdysone have also been identified in many arthropod species, and the amino acid sequences determined. The functional molting hormone receptors consist of two members of the nuclear receptor superfamily, namely the ecdysone receptor and the ultraspiracle, although the ecdysone receptor may be functional, in some instances, without the ultraspiracle. Generally, the ecdysone receptor/ultraspiracle heterodimer binds to a number of ecdysone response elements, sequence motifs that reside in the promoter of various ecdysteroid-responsive genes. In the ensuing transcriptional induction, the ecdysone receptor/ultraspiracle complex binds to 20-hydroxyecdysone or to a cognate ligand that, in turn, leads to the release of a corepressor and the recruitment of coactivators. 3D structures of the ligand-binding domains of the ecdysone receptor and the ultraspiracle have been solved for a few insect species. Ecdysone agonists bind to ecdysone receptors specifically, and ligand-ecdysone receptor binding is enhanced in the presence of the ultraspiracle in insects. The basic mode of ecdysteroid receptor action is highly conserved, but substantial functional differences exist among the receptors of individual species. Even though the transcriptional effects are apparently similar for ecdysteroids and nonsteroidal compounds such as diacylhydrazines, the binding shapes are different between them. The compounds having the strongest binding affinity to receptors ordinarily have strong molting hormone activity. The ability of the ecdysone receptor/ultraspiracle complex to manifest the effects of small lipophilic agonists has led to their use as gene switches for medical and agricultural applications.
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Affiliation(s)
- Yoshiaki Nakagawa
- Division of Applied Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-Ku, Kyoto 606-8502, Japan.
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Dawson HD, Collins G, Pyle R, Key M, Taub DD. The Retinoic Acid Receptor-alpha mediates human T-cell activation and Th2 cytokine and chemokine production. BMC Immunol 2008; 9:16. [PMID: 18416830 PMCID: PMC2394516 DOI: 10.1186/1471-2172-9-16] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 04/16/2008] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND We have recently demonstrated that all-trans-retinoic acid (ATRA) and 9-cis-retinoic acid (9-cis RA) promote IL-4, IL-5 and IL-13 synthesis, while decreasing IFN-gamma and TNF-alpha expression by activated human T cells and reduces the synthesis of IL-12p70 from accessory cells. Here, we have demonstrated that the observed effects using ATRA and 9-cis RA are shared with the clinically useful RAR ligand, 13-cis retinoic acid (13-cis RA), and the retinoic acid receptor-alpha (RAR-alpha)-selective agonist, AM580 but not with the RAR-beta/gamma ligand, 4-hydroxyphenylretinamide (4-HPR). RESULTS The increase in type 2 cytokine production by these retinoids correlated with the expression of the T cell activation markers, CD69 and CD38. The RAR-alpha-selective agonist, AM580 recapitulated all of the T cell activation and type 2 cytokine-inducing effects of ATRA and 9-cis-RA, while the RAR-alpha-selective antagonist, RO 41-5253, inhibited these effects. CONCLUSION These results strongly support a role for RAR-alpha engagement in the regulation of genes and proteins involved with human T cell activation and type 2 cytokine production.
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Affiliation(s)
- Harry D Dawson
- Laboratory of Immunology, Gerontology Research Center, National Institute on Aging, NIH, Baltimore, MD 21224, USA.
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