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Quartin E, Rosa S, Gonzalez-Anton S, Mosteo Lopez L, Francisco V, Duarte D, Lo Celso C, Pires das Neves R, Ferreira L. Nanoparticle-encapsulated retinoic acid for the modulation of bone marrow hematopoietic stem cell niche. Bioact Mater 2024; 34:311-325. [PMID: 38274293 PMCID: PMC10809008 DOI: 10.1016/j.bioactmat.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 12/16/2023] [Accepted: 12/21/2023] [Indexed: 01/27/2024] Open
Abstract
More effective approaches are needed in the treatment of blood cancers, in particular acute myeloid leukemia (AML), that are able to eliminate resistant leukemia stem cells (LSCs) at the bone marrow (BM), after a chemotherapy session, and then enhance hematopoietic stem cell (HSC) engraftment for the re-establishment of the HSC compartment. Here, we investigate whether light-activatable nanoparticles (NPs) encapsulating all-trans-retinoic acid (RA+NPs) could solve both problems. Our in vitro results show that mouse AML cells transfected with RA+NPs differentiate towards antitumoral M1 macrophages through RIG.1 and OASL gene expression. Our in vivo results further show that mouse AML cells transfected with RA+NPs home at the BM after transplantation in an AML mouse model. The photo-disassembly of the NPs within the grafted cells by a blue laser enables their differentiation towards a macrophage lineage. This macrophage activation seems to have systemic anti-leukemic effect within the BM, with a significant reduction of leukemic cells in all BM compartments, of animals treated with RA+NPs, when compared with animals treated with empty NPs. In a separate group of experiments, we show for the first time that normal HSCs transfected with RA+NPs show superior engraftment at the BM niche than cells without treatment or treated with empty NPs. This is the first time that the activity of RA is tested in terms of long-term hematopoietic reconstitution after transplant using an in situ activation approach without any exogenous priming or genetic conditioning of the transplanted cells. Overall, the approach documented here has the potential to improve consolidation therapy in AML since it allows a dual intervention in the BM niche: to tackle resistant leukemia and improve HSC engraftment at the same time.
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Affiliation(s)
- Emanuel Quartin
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
- IIIUC—Institute of Interdisciplinary Research, University of Coimbra, 3004-517, Coimbra, Portugal
| | - Susana Rosa
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
- IIIUC—Institute of Interdisciplinary Research, University of Coimbra, 3004-517, Coimbra, Portugal
| | - Sara Gonzalez-Anton
- Department of Life Sciences, Imperial College London, South Kensington Campus, The Francis Crick Institute, London, UK
- Haematopoietic Stem Cell Laboratory, The Francis Crick Institute, London, UK
| | - Laura Mosteo Lopez
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
- Department of Biomedicine, Faculdade de Medicina da Universidade do Porto (FMUP), Porto, Portugal
- Department of Onco-Hematology, Instituto Português de Oncologia (IPO)-Porto, Porto, Portugal
| | - Vitor Francisco
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
- IIIUC—Institute of Interdisciplinary Research, University of Coimbra, 3004-517, Coimbra, Portugal
| | - Delfim Duarte
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
- Department of Biomedicine, Faculdade de Medicina da Universidade do Porto (FMUP), Porto, Portugal
- Department of Onco-Hematology, Instituto Português de Oncologia (IPO)-Porto, Porto, Portugal
| | - Cristina Lo Celso
- Department of Life Sciences, Imperial College London, South Kensington Campus, The Francis Crick Institute, London, UK
- Haematopoietic Stem Cell Laboratory, The Francis Crick Institute, London, UK
| | - Ricardo Pires das Neves
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
- IIIUC—Institute of Interdisciplinary Research, University of Coimbra, 3004-517, Coimbra, Portugal
| | - Lino Ferreira
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, 3004-517, Coimbra, Portugal
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Yabut KCB, Isoherranen N. Impact of Intracellular Lipid Binding Proteins on Endogenous and Xenobiotic Ligand Metabolism and Disposition. Drug Metab Dispos 2023; 51:700-717. [PMID: 37012074 PMCID: PMC10197203 DOI: 10.1124/dmd.122.001010] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 03/16/2023] [Accepted: 02/10/2023] [Indexed: 04/05/2023] Open
Abstract
The family of intracellular lipid binding proteins (iLBPs) is comprised of 16 members of structurally related binding proteins that have ubiquitous tissue expression in humans. iLBPs collectively bind diverse essential endogenous lipids and xenobiotics. iLBPs solubilize and traffic lipophilic ligands through the aqueous milieu of the cell. Their expression is correlated with increased rates of ligand uptake into tissues and altered ligand metabolism. The importance of iLBPs in maintaining lipid homeostasis is well established. Fatty acid binding proteins (FABPs) make up the majority of iLBPs and are expressed in major organs relevant to xenobiotic absorption, distribution, and metabolism. FABPs bind a variety of xenobiotics including nonsteroidal anti-inflammatory drugs, psychoactive cannabinoids, benzodiazepines, antinociceptives, and peroxisome proliferators. FABP function is also associated with metabolic disease, making FABPs currently a target for drug development. Yet the potential contribution of FABP binding to distribution of xenobiotics into tissues and the mechanistic impact iLBPs may have on xenobiotic metabolism are largely undefined. This review examines the tissue-specific expression and functions of iLBPs, the ligand binding characteristics of iLBPs, their known endogenous and xenobiotic ligands, methods for measuring ligand binding, and mechanisms of ligand delivery from iLBPs to membranes and enzymes. Current knowledge of the importance of iLBPs in affecting disposition of xenobiotics is collectively described. SIGNIFICANCE STATEMENT: The data reviewed here show that FABPs bind many drugs and suggest that binding of drugs to FABPs in various tissues will affect drug distribution into tissues. The extensive work and findings with endogenous ligands suggest that FABPs may also alter the metabolism and transport of drugs. This review illustrates the potential significance of this understudied area.
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Affiliation(s)
- King Clyde B Yabut
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington
| | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington
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3
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Jeong H, Armstrong AT, Isoherranen N, Czuba L, Yang A, Zumpf K, Ciolino J, Torres E, Stika CS, Wisner KL. Temporal changes in the systemic concentrations of retinoids in pregnant and postpartum women. PLoS One 2023; 18:e0280424. [PMID: 36795769 PMCID: PMC9934425 DOI: 10.1371/journal.pone.0280424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/02/2023] [Indexed: 02/17/2023] Open
Abstract
Retinoids and vitamin A are essential for multiple biological functions, including vision and immune responses, as well as the development of an embryo during pregnancy. Despite its importance, alterations in retinoid homeostasis during normal human pregnancy are incompletely understood. We aimed to characterize the temporal changes in the systemic retinoid concentrations across pregnancy and postpartum period. Monthly blood samples were collected from twenty healthy pregnant women, and plasma concentrations of retinol, all-trans-retinoic acid (atRA), 13-cis-retinoic acid (13cisRA), and 4-oxo-retinoic acids were measured using liquid chromatography-tandem mass spectrometry. Significant decreases in 13cisRA concentrations over the pregnancy were observed, with rebound increases in retinol and 13cisRA levels after delivery. Of note, atRA concentrations exhibited a unique temporal pattern with levels peaking at mid-pregnancy. While the 4-oxo-atRA concentration was below the limit of quantification, 4-oxo-13cisRA was readily detectable, and its temporal change mimicked that of 13cisRA. The time profiles of atRA and 13cisRA remained similar after correction by albumin levels for plasma volume expansion adjustment. Together, the comprehensive profiling of systemic retinoid concentrations over the course of pregnancy provides insights into pregnancy-mediated changes in retinoid disposition to maintain its homeostasis.
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Affiliation(s)
- Hyunyoung Jeong
- Department of Industrial and Physical Pharmacy and Pharmacy Practice, College of Pharmacy, Purdue University, West Lafayette, IN, United States of America
- Department of Pharmacy Practice, College of Pharmacy, Purdue University, West Lafayette, IN, United States of America
| | - Abigail T. Armstrong
- Department of Industrial and Physical Pharmacy and Pharmacy Practice, College of Pharmacy, Purdue University, West Lafayette, IN, United States of America
| | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, United States of America
| | - Lindsay Czuba
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, United States of America
| | - Amy Yang
- Department of Preventive Medicine (Biostatistics), Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Katelynn Zumpf
- Department of Preventive Medicine (Biostatistics), Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Jody Ciolino
- Department of Preventive Medicine (Biostatistics), Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Elizabeth Torres
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Catherine S. Stika
- Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Katherine L. Wisner
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
- Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
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4
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Yabut KCB, Isoherranen N. CRABPs Alter all-trans-Retinoic Acid Metabolism by CYP26A1 via Protein-Protein Interactions. Nutrients 2022; 14:nu14091784. [PMID: 35565751 PMCID: PMC9105409 DOI: 10.3390/nu14091784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 12/02/2022] Open
Abstract
Cellular retinoic acid binding proteins (CRABP1 and CRABP2) bind all-trans-retinoic acid (atRA), the active metabolite of vitamin A, with high affinity. CRABP1 and CRABP2 have been shown to interact with the atRA-clearing cytochrome P450 enzymes CYP26B1 and CYP26C1 and with nuclear retinoic acid receptors (RARs). We hypothesized that CRABP1 and CRABP2 also alter atRA metabolism and clearance by CYP26A1, the third key atRA-metabolizing enzyme in the CYP26 family. Based on stopped-flow experiments, atRA bound CRABP1 and CRABP2 with Kd values of 4.7 nM and 7.6 nM, respectively. The unbound atRA Km values for 4-OH-atRA formation by CYP26A1 were 4.7 ± 0.8 nM with atRA, 6.8 ± 1.7 nM with holo-CRABP1 and 6.1 ± 2.7 nM with holo-CRABP2 as a substrate. In comparison, the apparent kcat value was about 30% lower (0.71 ± 0.07 min−1 for holo-CRABP1 and 0.75 ± 0.09 min−1 for holo-CRABP2) in the presence of CRABPs than with free atRA (1.07 ± 0.08 min−1). In addition, increasing concentrations in apo-CRABPs decreased the 4-OH-atRA formation rates by CYP26A1. Kinetic analyses suggest that apo-CRABP1 and apo-CRABP2 inhibit CYP26A1 (Ki = 0.39 nM and 0.53 nM, respectively) and holo-CRABPs channel atRA for metabolism by CYP26A1. These data suggest that CRABPs play a critical role in modulating atRA metabolism and cellular atRA concentrations.
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Napoli JL. Retinoic Acid: Sexually Dimorphic, Anti-Insulin and Concentration-Dependent Effects on Energy. Nutrients 2022; 14:1553. [PMID: 35458115 PMCID: PMC9027308 DOI: 10.3390/nu14081553] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 12/26/2022] Open
Abstract
This review addresses the fasting vs. re-feeding effects of retinoic acid (RA) biosynthesis and functions, and sexually dimorphic RA actions. It also discusses other understudied topics essential for understanding RA activities-especially interactions with energy-balance-regulating hormones, including insulin and glucagon, and sex hormones. This report will introduce RA homeostasis and hormesis to provide context. Essential context also will encompass RA effects on adiposity, muscle function and pancreatic islet development and maintenance. These comments provide background for explaining interactions among insulin, glucagon and cortisol with RA homeostasis and function. One aim would clarify the often apparent RA contradictions related to pancreagenesis vs. pancreas hormone functions. The discussion also will explore the adverse effects of RA on estrogen action, in contrast to the enhancing effects of estrogen on RA action, the adverse effects of androgens on RA receptors, and the RA induction of androgen biosynthesis.
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Affiliation(s)
- Joseph L Napoli
- Graduate Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, The University of California-Berkeley, Berkeley, CA 94704, USA
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6
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Everts HB, Akuailou EN. Retinoids in Cutaneous Squamous Cell Carcinoma. Nutrients 2021; 13:nu13010153. [PMID: 33466372 PMCID: PMC7824907 DOI: 10.3390/nu13010153] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 12/31/2020] [Accepted: 12/31/2020] [Indexed: 02/07/2023] Open
Abstract
Animal studies as early as the 1920s suggested that vitamin A deficiency leads to squamous cell metaplasia in numerous epithelial tissues including the skin. However, humans usually die from vitamin A deficiency before cancers have time to develop. A recent long-term cohort study found that high dietary vitamin A reduced the risk of cutaneous squamous cell carcinoma (cSCC). cSCC is a form of nonmelanoma skin cancer that primarily occurs from excess exposure to ultraviolet light B (UVB). These cancers are expensive to treat and can lead to metastasis and death. Oral synthetic retinoids prevent the reoccurrence of cSCC, but side effects limit their use in chemoprevention. Several proteins involved in vitamin A metabolism and signaling are altered in cSCC, which may lead to retinoid resistance. The expression of vitamin A metabolism proteins may also have prognostic value. This article reviews what is known about natural and synthetic retinoids and their metabolism in cSCC.
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7
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Ferreira R, Napoli J, Enver T, Bernardino L, Ferreira L. Advances and challenges in retinoid delivery systems in regenerative and therapeutic medicine. Nat Commun 2020; 11:4265. [PMID: 32848154 PMCID: PMC7450074 DOI: 10.1038/s41467-020-18042-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 08/01/2020] [Indexed: 12/19/2022] Open
Abstract
Retinoids regulate a wide spectrum of cellular functions from the embryo throughout adulthood, including cell differentiation, metabolic regulation, and inflammation. These traits make retinoids very attractive molecules for medical purposes. In light of some of the physicochemical limitations of retinoids, the development of drug delivery systems offers several advantages for clinical translation of retinoid-based therapies, including improved solubilization, prolonged circulation, reduced toxicity, sustained release, and improved efficacy. In this Review, we discuss advances in preclinical and clinical tests regarding retinoid formulations, specifically the ones based in natural retinoids, evaluated in the context of regenerative medicine, brain, cancer, skin, and immune diseases. Advantages and limitations of retinoid formulations, as well as prospects to push the field forward, will be presented.
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Grants
- MC_U137973817 Medical Research Council
- MR/N000838/1 Medical Research Council
- The authors would like to thank Andreia Vilaça for the illustrations and the financial support of ERA Chair project (ERA@UC, ref:669088) through EU Horizon 2020 program, the POCI-01-0145-FEDER-016390 (acronym: CANCEL STEM) and POCI-01-0145-FEDER-029414 (acronym: LIghtBRARY) projects through Compete 2020 and FCT programs, projects 2IQBIONEURO (reference: 0624_2IQBIONEURO_6_E) and NEUROATLANTIC (reference: EAPA_791/2018) co-funded by INTERREG (Atlantic program or V-A Spain-Portugal) and European fund for Regional Development (FEDER), FCT (Portugal, SFRH/BPD/102103/2014), National Funds by Foundation for Science and Technology (UID/Multi/00709/2013), “Programa Operacional do Centro, Centro 2020” through the funding of the ICON project (Interdisciplinary Challenges On Neurodegeneration; CENTRO-01-0145-FEDER-000013), EXPL/BIM-MED/0822/2013 (LB), (SFRH/BPD/94228/2013, IF/00178/2015) (RF), Cerebrovascular Disease Grant and L’Oréal-UNESCO Portugal for Women in Science for supporting this work. Authors declare there are no conflict of interests.
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Affiliation(s)
- Raquel Ferreira
- Health Sciences Research Centre (CICS-UBI), Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal
| | - Joseph Napoli
- Nutritional Sciences and Toxicology, University of California, 231 Morgan Hall, MC#3104, Berkeley, CA, 94720, USA
| | - Tariq Enver
- UCL Cancer Institute, University College London, London, UK
| | - Liliana Bernardino
- Health Sciences Research Centre (CICS-UBI), Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal.
| | - Lino Ferreira
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
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Lin YL, Lin YW, Nhieu J, Zhang X, Wei LN. Sonic Hedgehog-Gli1 Signaling and Cellular Retinoic Acid Binding Protein 1 Gene Regulation in Motor Neuron Differentiation and Diseases. Int J Mol Sci 2020; 21:ijms21114125. [PMID: 32527063 PMCID: PMC7312406 DOI: 10.3390/ijms21114125] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/03/2020] [Accepted: 06/07/2020] [Indexed: 12/22/2022] Open
Abstract
Cellular retinoic acid-binding protein 1 (CRABP1) is highly expressed in motor neurons. Degenerated motor neuron-like MN1 cells are engineered by introducing SODG93A or AR-65Q to model degenerated amyotrophic lateral sclerosis (ALS) or spinal bulbar muscular atrophy neurons. Retinoic acid (RA)/sonic hedgehog (Shh)-induced embryonic stem cells differentiation into motor neurons are employed to study up-regulation of Crabp1 by Shh. In SODG93A or AR-65Q MN1 neurons, CRABP1 level is reduced, revealing a correlation of motor neuron degeneration with Crabp1 down-regulation. Up-regulation of Crabp1 by Shh is mediated by glioma-associated oncogene homolog 1 (Gli1) that binds the Gli target sequence in Crabp1′s neuron-specific regulatory region upstream of minimal promoter. Gli1 binding triggers chromatin juxtaposition with minimal promoter, activating transcription. Motor neuron differentiation and Crabp1 up-regulation are both inhibited by blunting Shh with Gli inhibitor GANT61. Expression data mining of ALS and spinal muscular atrophy (SMA) motor neurons shows reduced CRABP1, coincided with reduction in Shh-Gli1 signaling components. This study reports motor neuron degeneration correlated with down-regulation in Crabp1 and Shh-Gli signaling. Shh-Gli up-regulation of Crabp1 involves specific chromatin remodeling. The physiological and pathological implication of this regulatory pathway in motor neuron degeneration is supported by gene expression data of ALS and SMA patients.
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Affiliation(s)
| | | | | | | | - Li-Na Wei
- Correspondence: ; Tel.: +1-612-6259402
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9
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Beedle MT, Stevison F, Zhong G, Topping T, Hogarth C, Isoherranen N, Griswold MD. Sources of all-trans retinal oxidation independent of the aldehyde dehydrogenase 1A isozymes exist in the postnatal testis†. Biol Reprod 2020; 100:547-560. [PMID: 30247516 DOI: 10.1093/biolre/ioy200] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/01/2018] [Accepted: 09/11/2018] [Indexed: 02/06/2023] Open
Abstract
Despite the essential role of the active metabolite of vitamin A, all-trans retinoic acid (atRA) in spermatogenesis, the enzymes, and cellular populations responsible for its synthesis in the postnatal testis remain largely unknown. The aldehyde dehydrogenase 1A (ALDH1A) family of enzymes residing within Sertoli cells is responsible for the synthesis of atRA, driving the first round of spermatogenesis. Those studies also revealed that the atRA required to drive subsequent rounds of spermatogenesis is possibly derived from the ALDH1A enzymes residing within the meiotic and post-meiotic germ cells. Three ALDH1A isozymes (ALDH1A1, ALDH1A2, and ALDH1A3) are present in the testis. Although, ALDH1A1 is expressed in adult Sertoli cells and is suggested to contribute to the atRA required for the pre-meiotic transitions, ALDH1A2 is proposed to be the essential isomer involved in testicular atRA biosynthesis. In this report, we first examine the requirement for ALDH1A2 via the generation and analysis of a conditional Aldh1a2 germ cell knockout and a tamoxifen-induced Aldh1a2 knockout model. We then utilized the pan-ALDH1A inhibitor (WIN 18446) to test the collective contribution of the ALDH1A enzymes to atRA biosynthesis following the first round of spermatogenesis. Collectively, our data provide the first in vivo evidence demonstrating that animals severely deficient in ALDH1A2 postnatally proceed normally through spermatogenesis. Our studies with a pan-ALDH1A inhibitor (WIN 18446) also suggest that an alternative source of atRA biosynthesis independent of the ALDH1A enzymes becomes available to maintain atRA levels for several spermatogenic cycles following an initial atRA injection.
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Affiliation(s)
- My-Thanh Beedle
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
| | - Faith Stevison
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Guo Zhong
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Traci Topping
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
| | - Cathryn Hogarth
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Michael D Griswold
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
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10
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Isoherranen N, Zhong G. Biochemical and physiological importance of the CYP26 retinoic acid hydroxylases. Pharmacol Ther 2019; 204:107400. [PMID: 31419517 PMCID: PMC6881548 DOI: 10.1016/j.pharmthera.2019.107400] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/06/2019] [Indexed: 12/19/2022]
Abstract
The Cytochrome P450 (CYP) family 26 enzymes contribute to retinoic acid (RA) metabolism and homeostasis in humans, mammals and other chordates. The three CYP26 family enzymes, CYP26A1, CYP26B1 and CYP26C1 have all been shown to metabolize all-trans-retinoic acid (atRA) it's 9-cisRA and 13-cisRA isomers and primary metabolites 4-OH-RA and 4-oxo-RA with high efficiency. While no crystal structures of CYP26 enzymes are available, the binding of various ligands has been extensively explored via homology modeling. All three CYP26 enzymes are inducible by treatment with atRA in various prenatal and postnatal tissues and cell types. However, current literature shows that in addition to regulation by atRA, CYP26 enzyme expression is also regulated by other endogenous processes and inflammatory cytokines. In humans and in animal models the expression patterns of CYP26 enzymes have been shown to be tissue and cell type specific, and the expression of the CYP26 enzymes is believed to regulate the formation of critical atRA concentration gradients in various tissue types. Yet, very little data exists on direct disease associations of altered CYP26 expression or activity. Nevertheless, data is emerging describing a variety of human genetic variations in the CYP26 enzymes that are associated with different pathologies. Interestingly, some of these genetic variants result in increased activity of the CYP26 enzymes potentially leading to complex gene-environment interactions due to variability in dietary intake of retinoids. This review highlights the current knowledge of structure-function of CYP26 enzymes and focuses on their role in human retinoid metabolism in different tissues.
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Affiliation(s)
- Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA.
| | - Guo Zhong
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA
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11
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Wang S, Yu J, Kane MA, Moise AR. Modulation of retinoid signaling: therapeutic opportunities in organ fibrosis and repair. Pharmacol Ther 2019; 205:107415. [PMID: 31629008 DOI: 10.1016/j.pharmthera.2019.107415] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/17/2019] [Indexed: 02/08/2023]
Abstract
The vitamin A metabolite, retinoic acid, is an important signaling molecule during embryonic development serving critical roles in morphogenesis, organ patterning and skeletal and neural development. Retinoic acid is also important in postnatal life in the maintenance of tissue homeostasis, while retinoid-based therapies have long been used in the treatment of a variety of cancers and skin disorders. As the number of people living with chronic disorders continues to increase, there is great interest in extending the use of retinoid therapies in promoting the maintenance and repair of adult tissues. However, there are still many conflicting results as we struggle to understand the role of retinoic acid in the multitude of processes that contribute to tissue injury and repair. This review will assess our current knowledge of the role retinoic acid signaling in the development of fibroblasts, and their transformation to myofibroblasts, and of the potential use of retinoid therapies in the treatment of organ fibrosis.
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Affiliation(s)
- Suya Wang
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Jianshi Yu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201, USA
| | - Maureen A Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201, USA.
| | - Alexander R Moise
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, ON P3E 2C6, Canada; Departments of Chemistry and Biochemistry, and Biology and Biomolecular Sciences Program, Laurentian University, Sudbury, ON, P3E 2C6, Canada.
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12
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Wang S, Moise AR. Recent insights on the role and regulation of retinoic acid signaling during epicardial development. Genesis 2019; 57:e23303. [PMID: 31066193 PMCID: PMC6682438 DOI: 10.1002/dvg.23303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 12/18/2022]
Abstract
The vitamin A metabolite, retinoic acid, carries out essential and conserved roles in vertebrate heart development. Retinoic acid signals via retinoic acid receptors (RAR)/retinoid X receptors (RXRs) heterodimers to induce the expression of genes that control cell fate specification, proliferation, and differentiation. Alterations in retinoic acid levels are often associated with congenital heart defects. Therefore, embryonic levels of retinoic acid need to be carefully regulated through the activity of enzymes, binding proteins and transporters involved in vitamin A metabolism. Here, we review evidence of the complex mechanisms that control the fetal uptake and synthesis of retinoic acid from vitamin A precursors. Next, we highlight recent evidence of the role of retinoic acid in orchestrating myocardial compact zone growth and coronary vascular development.
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Affiliation(s)
- Suya Wang
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Alexander R. Moise
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, ON P3E 2C6, Canada
- Departments of Chemistry and Biochemistry, and Biology and Biomolecular Sciences Program, Laurentian University, Sudbury, ON, P3E 2C6 Canada
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, 66045, USA
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13
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Involvement of the retinoic acid signaling pathway in sex differentiation and pubertal development in the European sea bass Dicentrarchus labrax. Heliyon 2019; 5:e01201. [PMID: 30839897 PMCID: PMC6365411 DOI: 10.1016/j.heliyon.2019.e01201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 12/23/2022] Open
Abstract
Retinoic Acid (RA) is a vitamin A derivative present in many biological processes including embryogenesis, organ development and cell differentiation. The RA signaling pathway is essential for the onset of meiosis in tetrapods, although its role in fish reproduction needs further evidence. This study reports the expression profiles of several genes involved in this pathway during sex differentiation and the first reproductive season in European sea bass (Dicentrarchus labrax) gonads. The assessed genes are representative of several steps of the pathway including retinol transport, RA synthesis, nuclear receptors, RA transport and degradation. The study includes a synteny analysis of stra8, a tetrapod meiosis gatekeeper, in several taxa. The results show that, these genes were overexpressed during early gonad development and their expression decreased during meiosis progression in males and during vitellogenesis in females. Specifically, a decrease of cyp26a1, involved in RA degradation, together with an increase of aldh1a2 and aldh1a3, in charge of RA-synthesis, might ensure the availability of high RA levels at the time of meiosis in males and females. Moreover, the absence of stra8 in the European sea bass genome, as well as the conserved genomic neighbourhood found in other taxa, suggest a stra8 independent signaling for RA during meiosis. Taken together, our results might help to better understand the role of RA signaling in teleost gonad development.
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Jin L, Chang C, Pawlik KM, Datta A, Johnson LM, Vu T, Napoli JL, Datta PK. Serine Threonine Kinase Receptor-Associated Protein Deficiency Impairs Mouse Embryonic Stem Cells Lineage Commitment Through CYP26A1-Mediated Retinoic Acid Homeostasis. Stem Cells 2018; 36:1368-1379. [PMID: 29781215 DOI: 10.1002/stem.2854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/01/2018] [Accepted: 05/01/2018] [Indexed: 01/07/2023]
Abstract
Retinoic acid (RA) signaling is essential for the differentiation of embryonic stem cells (ESCs) and vertebrate development. RA biosynthesis and metabolism are controlled by a series of enzymes, but the molecular regulators of these enzymes remain largely obscure. In this study, we investigated the functional role of the WD-domain protein STRAP (serine threonine kinase receptor-associated protein) in the pluripotency and lineage commitment of murine ESCs. We generated Strap knockout (KO) mouse ESCs and subjected them to spontaneous differentiation. We observed that, despite the unchanged characteristics of ESCs, Strap KO ESCs exhibited defects for lineage differentiation. Signature gene expression analyses revealed that Strap deletion attenuated intracellular RA signaling in embryoid bodies (EBs), and exogenous RA significantly rescued this deficiency. Moreover, loss of Strap selectively induced Cyp26A1 expression in mouse EBs, suggesting a potential role of STRAP in RA signaling. Mechanistically, we identified putative Krüppel-like factor 9 (KLF9) binding motifs to be critical in the enhancement of non-canonical RA-induced transactivation of Cyp26A1. Increased KLF9 expression in the absence of STRAP is partially responsible for Cyp26A1 induction. Interestingly, STRAP knockdown in Xenopus embryos influenced anterior-posterior neural patterning and impaired the body axis and eye development during early Xenopus embryogenesis. Taken together, our study reveals an intrinsic role for STRAP in the regulation of RA signaling and provides new molecular insights for ESC fate determination. Stem Cells 2018;36:1368-1379.
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Affiliation(s)
- Lin Jin
- Division of Hematology and Oncology, Department of Medicine, UAB Comprehensive Cancer Center, Birmingham, Alabama, USA.,Birmingham Veterans Affairs Medical Center, Birmingham, Alabama, USA
| | - Chenbei Chang
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kevin M Pawlik
- Department of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Arunima Datta
- Division of Hematology and Oncology, Department of Medicine, UAB Comprehensive Cancer Center, Birmingham, Alabama, USA.,Birmingham Veterans Affairs Medical Center, Birmingham, Alabama, USA
| | - Larry M Johnson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Trung Vu
- Division of Hematology and Oncology, Department of Medicine, UAB Comprehensive Cancer Center, Birmingham, Alabama, USA
| | - Joseph L Napoli
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California, USA
| | - Pran K Datta
- Division of Hematology and Oncology, Department of Medicine, UAB Comprehensive Cancer Center, Birmingham, Alabama, USA.,Birmingham Veterans Affairs Medical Center, Birmingham, Alabama, USA
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15
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Zhong G, Ortiz D, Zelter A, Nath A, Isoherranen N. CYP26C1 Is a Hydroxylase of Multiple Active Retinoids and Interacts with Cellular Retinoic Acid Binding Proteins. Mol Pharmacol 2018; 93:489-503. [PMID: 29476041 DOI: 10.1124/mol.117.111039] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/22/2018] [Indexed: 01/10/2023] Open
Abstract
The clearance of retinoic acid (RA) and its metabolites is believed to be regulated by the CYP26 enzymes, but the specific roles of CYP26A1, CYP26B1, and CYP26C1 in clearing active vitamin A metabolites have not been defined. The goal of this study was to establish the substrate specificity of CYP26C1, and determine whether CYP26C1 interacts with cellular retinoic acid binding proteins (CRABPs). CYP26C1 was found to effectively metabolize all-trans retinoic acid (atRA), 9-cis-retinoic acid (9-cis-RA), 13-cis-retinoic acid, and 4-oxo-atRA with the highest intrinsic clearance toward 9-cis-RA. In comparison with CYP26A1 and CYP26B1, CYP26C1 resulted in a different metabolite profile for retinoids, suggesting differences in the active-site structure of CYP26C1 compared with other CYP26s. Homology modeling of CYP26C1 suggested that this is attributable to the distinct binding orientation of retinoids within the CYP26C1 active site. In comparison with other CYP26 family members, CYP26C1 was up to 10-fold more efficient in clearing 4-oxo-atRA (intrinsic clearance 153 μl/min/pmol) than CYP26A1 and CYP26B1, suggesting that CYP26C1 may be important in clearing this active retinoid. In support of this, CRABPs delivered 4-oxo-atRA and atRA for metabolism by CYP26C1. Despite the tight binding of 4-oxo-atRA and atRA with CRABPs, the apparent Michaelis-Menten constant in biological matrix (Km) value of these substrates with CYP26C1 was not increased when the substrates were bound with CRABPs, in contrast to what is predicted by free drug hypothesis. Together these findings suggest that CYP26C1 is a 4-oxo-atRA hydroxylase and may be important in regulating the concentrations of this active retinoid in human tissues.
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Affiliation(s)
- Guo Zhong
- Departments of Pharmaceutics (G.Z., N.I.) and Medicinal Chemistry (D.O., A.N.), School of Pharmacy, and Department of Biochemistry, School of Medicine (A.Z.), University of Washington, Seattle, Washington
| | - David Ortiz
- Departments of Pharmaceutics (G.Z., N.I.) and Medicinal Chemistry (D.O., A.N.), School of Pharmacy, and Department of Biochemistry, School of Medicine (A.Z.), University of Washington, Seattle, Washington
| | - Alex Zelter
- Departments of Pharmaceutics (G.Z., N.I.) and Medicinal Chemistry (D.O., A.N.), School of Pharmacy, and Department of Biochemistry, School of Medicine (A.Z.), University of Washington, Seattle, Washington
| | - Abhinav Nath
- Departments of Pharmaceutics (G.Z., N.I.) and Medicinal Chemistry (D.O., A.N.), School of Pharmacy, and Department of Biochemistry, School of Medicine (A.Z.), University of Washington, Seattle, Washington
| | - Nina Isoherranen
- Departments of Pharmaceutics (G.Z., N.I.) and Medicinal Chemistry (D.O., A.N.), School of Pharmacy, and Department of Biochemistry, School of Medicine (A.Z.), University of Washington, Seattle, Washington
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Abstract
Multiple binding and transport proteins facilitate many aspects of retinoid biology through effects on retinoid transport, cellular uptake, metabolism, and nuclear delivery. These include the serum retinol binding protein sRBP (aka Rbp4), the plasma membrane sRBP receptor Stra6, and the intracellular retinoid binding-proteins such as cellular retinol-binding proteins (CRBP) and cellular retinoic acid binding-proteins (CRABP). sRBP transports the highly lipophilic retinol through an aqueous medium. The major intracellular retinol-binding protein, CRBP1, likely enhances efficient retinoid use by providing a sink to facilitate retinol uptake from sRBP through the plasma membrane or via Stra6, delivering retinol or retinal to select enzymes that generate retinyl esters or retinoic acid, and protecting retinol/retinal from excess catabolism or opportunistic metabolism. Intracellular retinoic acid binding-proteins (CRABP1 and 2, and FABP5) seem to have more diverse functions distinctive to each, such as directing retinoic acid to catabolism, delivering retinoic acid to specific nuclear receptors, and generating non-canonical actions. Gene ablation of intracellular retinoid binding-proteins does not cause embryonic lethality or gross morphological defects. Metabolic and functional defects manifested in knockouts of CRBP1, CRBP2 and CRBP3, however, illustrate their essentiality to health, and in the case of CRBP2, to survival during limited dietary vitamin A. Future studies should continue to address the specific molecular interactions that occur between retinoid binding-proteins and their targets and their precise physiologic contributions to retinoid homeostasis and function.
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Affiliation(s)
- Joseph L Napoli
- Graduate Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, 119 Morgan Hall, 94720, Berkeley, CA, USA.
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17
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Napoli JL. Cellular retinoid binding-proteins, CRBP, CRABP, FABP5: Effects on retinoid metabolism, function and related diseases. Pharmacol Ther 2017; 173:19-33. [PMID: 28132904 DOI: 10.1016/j.pharmthera.2017.01.004] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cellular binding-proteins (BP), including CRBP1, CRBP2, CRABP1, CRABP2, and FABP5, shepherd the poorly aqueous soluble retinoids during uptake, metabolism and function. Holo-BP promote efficient use of retinol, a scarce but essential nutrient throughout evolution, by sheltering it and its major metabolite all-trans-retinoic acid from adventitious interactions with the cellular milieu, and by imposing specificity of delivery to enzymes, nuclear receptors and other partners. Apo-BP reflect cellular retinoid status and modify activities of retinoid metabolon enzymes, or exert non-canonical actions. High ligand binding affinities and the nature of ligand sequestration necessitate external factors to prompt retinoid release from holo-BP. One or more of cross-linking, kinetics, and colocalization have identified these factors as RDH, RALDH, CYP26, LRAT, RAR and PPARβ/δ. Michaelis-Menten and other kinetic approaches verify that BP channel retinoids to select enzymes and receptors by protein-protein interactions. Function of the BP and enzymes that constitute the retinoid metabolon depends in part on retinoid exchanges unique to specific pairings. The complexity of these exchanges configure retinol metabolism to meet the diverse functions of all-trans-retinoic acid and its ability to foster contrary outcomes in different cell types, such as inducing apoptosis, differentiation or proliferation. Altered BP expression affects retinoid function, for example, by impairing pancreas development resulting in abnormal glucose and energy metabolism, promoting predisposition to breast cancer, and fostering more severe outcomes in prostate cancer, ovarian adenocarcinoma, and glioblastoma. Yet, the extent of BP interactions with retinoid metabolon enzymes and their impact on retinoid physiology remains incompletely understood.
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Affiliation(s)
- Joseph L Napoli
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720, United States.
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18
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Metzler MA, Sandell LL. Enzymatic Metabolism of Vitamin A in Developing Vertebrate Embryos. Nutrients 2016; 8:E812. [PMID: 27983671 PMCID: PMC5188467 DOI: 10.3390/nu8120812] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/09/2016] [Accepted: 12/13/2016] [Indexed: 12/16/2022] Open
Abstract
Embryonic development is orchestrated by a small number of signaling pathways, one of which is the retinoic acid (RA) signaling pathway. Vitamin A is essential for vertebrate embryonic development because it is the molecular precursor of the essential signaling molecule RA. The level and distribution of RA signaling within a developing embryo must be tightly regulated; too much, or too little, or abnormal distribution, all disrupt embryonic development. Precise regulation of RA signaling during embryogenesis is achieved by proteins involved in vitamin A metabolism, retinoid transport, nuclear signaling, and RA catabolism. The reversible first step in conversion of the precursor vitamin A to the active retinoid RA is mediated by retinol dehydrogenase 10 (RDH10) and dehydrogenase/reductase (SDR family) member 3 (DHRS3), two related membrane-bound proteins that functionally activate each other to mediate the interconversion of retinol and retinal. Alcohol dehydrogenase (ADH) enzymes do not contribute to RA production under normal conditions during embryogenesis. Genes involved in vitamin A metabolism and RA catabolism are expressed in tissue-specific patterns and are subject to feedback regulation. Mutations in genes encoding these proteins disrupt morphogenesis of many systems in a developing embryo. Together these observations demonstrate the importance of vitamin A metabolism in regulating RA signaling during embryonic development in vertebrates.
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Affiliation(s)
- Melissa A Metzler
- Department of Molecular, Cellular and Craniofacial Biology, University of Louisville, Louisville, KY 40201, USA.
| | - Lisa L Sandell
- Department of Molecular, Cellular and Craniofacial Biology, University of Louisville, Louisville, KY 40201, USA.
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19
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Nelson CH, Peng CC, Lutz JD, Yeung CK, Zelter A, Isoherranen N. Direct protein-protein interactions and substrate channeling between cellular retinoic acid binding proteins and CYP26B1. FEBS Lett 2016; 590:2527-35. [PMID: 27416800 DOI: 10.1002/1873-3468.12303] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/23/2016] [Accepted: 06/29/2016] [Indexed: 11/11/2022]
Abstract
Cellular retinoic acid binding proteins (CRABPs) bind all-trans-retinoic acid (atRA) tightly. This study aimed to determine whether atRA is channeled directly to cytochrome P450 (CYP) CYP26B1 by CRABPs, and whether CRABPs interact directly with CYP26B1. atRA bound to CRABPs (holo-CRABP) was efficiently metabolized by CYP26B1. Isotope dilution experiments showed that delivery of atRA to CYP26B1 in solution was similar with or without CRABP. Holo-CRABPs had higher affinity for CYP26B1 than free atRA, but both apo-CRABPs inhibited the formation of 4-OH-RA by CYP26B1. Similar protein-protein interactions between soluble binding proteins and CYPs may be important for other lipophilic CYP substrates.
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Affiliation(s)
- Cara H Nelson
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Chi-Chi Peng
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Justin D Lutz
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Catherine K Yeung
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Alex Zelter
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
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20
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Liu RZ, Li S, Garcia E, Glubrecht DD, Poon HY, Easaw JC, Godbout R. Association between cytoplasmic CRABP2, altered retinoic acid signaling, and poor prognosis in glioblastoma. Glia 2016; 64:963-76. [PMID: 26893190 DOI: 10.1002/glia.22976] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 01/22/2016] [Accepted: 01/25/2016] [Indexed: 12/26/2022]
Abstract
Retinoic acid (RA), a metabolite of vitamin A, is required for the regulation of growth and development. Aberrant expression of molecules involved in RA signaling has been reported in various cancer types including glioblastoma multiforme (GBM). Cellular retinoic acid-binding protein 2 (CRABP2) has previously been shown to play a key role in the transport of RA to retinoic acid receptors (RARs) to activate their transcription regulatory activity. Here, we demonstrate that CRABP2 is predominantly located in the cytoplasm of GBM tumors. Cytoplasmic, but not nuclear, CRABP2 levels in GBM tumors are associated with poor patient survival. Treatment of malignant glioma cell lines with RA results in a dose-dependent increase in accumulation of CRABP2 in the cytoplasm. CRABP2 knockdown reduces proliferation rates of malignant glioma cells, and enhances RA-induced RAR activation. Levels of CRYAB, a small heat shock protein with anti-apoptotic activity, and GFAP, an astrocyte-specific intermediate filament protein, are greatly reduced in CRABP2-depleted cells. Restoration of CRYAB expression partially but significantly reversed the effect of CRABP2 depletion on RAR activation. Our combined in vivo and in vitro data indicate that: (i) CRABP2 is an important determinant of clinical outcome in GBM patients, and (ii) the mechanism of action of CRABP2 in GBM involves sequestration of RA in the cytoplasm and activation of an anti-apoptotic pathway, thereby enhancing proliferation and preventing RA-mediated cell death and differentiation. We propose that reducing CRABP2 levels may enhance the therapeutic index of RA in GBM patients.
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Affiliation(s)
- Rong-Zong Liu
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, T6G 1Z2, Canada
| | - Shuai Li
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, T6G 1Z2, Canada
| | - Elizabeth Garcia
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, T6G 1Z2, Canada
| | - Darryl D Glubrecht
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, T6G 1Z2, Canada
| | - Ho Yin Poon
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, T6G 1Z2, Canada
| | - Jacob C Easaw
- Division of Medical Oncology, University of Calgary, Calgary, Alberta, T2N 4N2, Canada
| | - Roseline Godbout
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, T6G 1Z2, Canada
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Abstract
Retinoic acid (RA) was identified as the biologically active form of vitamin A almost 70 years ago and work on its function and mechanism of action is still of major interest both from a scientific and a clinical perspective. The currently accepted model postulates that RA is produced in two sequential oxidative steps: first, retinol is oxidized reversibly to retinaldehyde, and then retinaldehyde is oxidized irreversibly to RA. Excess RA is inactivated by conversion to hydroxylated derivatives. Much is left to learn, especially about retinoid binding proteins and the trafficking of the hydrophobic retinoid substrates between membrane bound and cytosolic enzymes. Here, background on development of the field and an update on recent advances in our understanding of the enzymatic pathways and mechanisms that control the rate of RA production and degradation are presented with a focus on the many questions that remain unanswered.
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Liu RZ, Garcia E, Glubrecht DD, Poon HY, Mackey JR, Godbout R. CRABP1 is associated with a poor prognosis in breast cancer: adding to the complexity of breast cancer cell response to retinoic acid. Mol Cancer 2015; 14:129. [PMID: 26142905 PMCID: PMC4491424 DOI: 10.1186/s12943-015-0380-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/07/2015] [Indexed: 12/31/2022] Open
Abstract
Background Clinical trials designed to test the efficacy of retinoic acid (RA) as an adjuvant for the treatment of solid cancers have been disappointing, primarily due to RA resistance. Estrogen receptor (ER)-negative breast cancer cells are more resistant to RA than ER-positive cells. The expression and subcellular distribution of two RA-binding proteins, FABP5 and CRABP2, has already been shown to play critical roles in breast cancer cell response to RA. CRABP1, a third member of the RA-binding protein family, has not previously been investigated as a possible mediator of RA action in breast cancer. Methods CRABP1 and CRABP2 expression in primary breast tumor tissues was analyzed using gene expression and tissue microarrays. CRABP1 levels were manipulated using siRNAs and by transient overexpression. RA-induced subcellular translocation of CRABPs was examined by immunofluorescence microscopy and immunoblotting. RA-induced transactivation of RAR was analyzed using a RA response element (RARE)-driven luciferase reporter system. Effects of CRABP1 expression and RA treatment on downstream gene expression were investigated by semi-quantitative RT-PCR analysis. Results Compared to normal mammary tissues, CRABP1 expression is significantly down-regulated in ER+ breast tumors, but maintained in triple-negative breast cancers. Elevated CRABP1 levels are associated with poor patient prognosis, high Ki67 immunoreactivity and high tumor grade in breast cancer. The prognostic significance of CRABP1 is attributed to its cytoplasmic localization. We demonstrate that CRABP1 expression attenuates RA-induced cell growth arrest and inhibits RA signalling in breast cancer cells by sequestering RA in the cytoplasm. We also show that CRABP1 affects the expression of genes involved in RA biosynthesis, trafficking and metabolism. Conclusions CRABP1 is an adverse factor for clinical outcome in triple-negative breast cancer and a potent inhibitor of RA signalling in breast cancer cells. Our data indicate that CRABP1, in conjunction with previously identified CRABP2 and FABP5, plays a key role in breast cancer cell response to RA. We propose that these three RA-binding proteins can serve as biomarkers for predicting triple-negative breast cancer response to RA, with elevated levels of either cytoplasmic CRABP1 or FABP5 associated with RA resistance, and elevated levels of nuclear CRABP2 associated with sensitivity to RA. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0380-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rong-Zong Liu
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, T6G 1Z2, AB, Canada
| | - Elizabeth Garcia
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, T6G 1Z2, AB, Canada
| | - Darryl D Glubrecht
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, T6G 1Z2, AB, Canada
| | - Ho Yin Poon
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, T6G 1Z2, AB, Canada
| | - John R Mackey
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, T6G 1Z2, AB, Canada
| | - Roseline Godbout
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, T6G 1Z2, AB, Canada.
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Role of Retinoic Acid-Metabolizing Cytochrome P450s, CYP26, in Inflammation and Cancer. ADVANCES IN PHARMACOLOGY 2015; 74:373-412. [PMID: 26233912 DOI: 10.1016/bs.apha.2015.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Vitamin A (retinol) and its active metabolite, all-trans-retinoic acid (atRA), play critical roles in regulating the differentiation, growth, and migration of immune cells. Similarly, as critical signaling molecules in the regulation of the cell cycle, retinoids are important in cancers. Concentrations of atRA are tightly regulated in tissues, predominantly by the availability of retinol, synthesis of atRA by ALDH1A enzymes and metabolism and clearance of atRA by CYP26 enzymes. The ALDH1A and CYP26 enzymes are expressed in several cell types in the immune system and in cancer cells. In the immune system, the ALDH1A and CYP26 enzymes appear to modulate RA concentrations. Consequently, alterations in the activity of ALDH1A and CYP26 enzymes are expected to change disease outcomes in inflammation. There is increasing evidence from various disease models of intestinal and skin inflammation that treatment with atRA has a positive effect on disease markers. However, whether aberrant atRA concentrations or atRA synthesis and metabolism play a role in inflammatory disease development and progression is not well understood. In cancers, especially in acute promyelocytic leukemia and neuroblastoma, increasing intracellular concentrations of atRA appears to provide clinical benefit. Inhibition of the CYP26 enzymes to increase atRA concentrations and combat therapy resistance has been pursued as a drug target in these cancers. This chapter covers the current knowledge of how atRA and retinol regulate the immune system and inflammation, how retinol and atRA metabolism is altered in inflammation and cancer, and what roles atRA-metabolizing enzymes have in immune responses and cancers.
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Kono N, Arai H. Intracellular transport of fat-soluble vitamins A and E. Traffic 2014; 16:19-34. [PMID: 25262571 DOI: 10.1111/tra.12231] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/11/2022]
Abstract
Vitamins are compounds that are essential for the normal growth, reproduction and functioning of the human body. Of the 13 known vitamins, vitamins A, D, E and K are lipophilic compounds and are therefore called fat-soluble vitamins. Because of their lipophilicity, fat-soluble vitamins are solubilized and transported by intracellular carrier proteins to exert their actions and to be metabolized properly. Vitamin A and its derivatives, collectively called retinoids, are solubilized by intracellular retinoid-binding proteins such as cellular retinol-binding protein (CRBP), cellular retinoic acid-binding protein (CRABP) and cellular retinal-binding protein (CRALBP). These proteins act as chaperones that regulate the metabolism, signaling and transport of retinoids. CRALBP-mediated intracellular retinoid transport is essential for vision in human. α-Tocopherol, the main form of vitamin E found in the body, is transported by α-tocopherol transfer protein (α-TTP) in hepatic cells. Defects of α-TTP cause vitamin E deficiency and neurological disorders in humans. Recently, it has been shown that the interaction of α-TTP with phosphoinositides plays a critical role in the intracellular transport of α-tocopherol and is associated with familial vitamin E deficiency. In this review, we summarize the mechanisms and biological significance of the intracellular transport of vitamins A and E.
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Affiliation(s)
- Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
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25
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Blum N, Begemann G. The roles of endogenous retinoid signaling in organ and appendage regeneration. Cell Mol Life Sci 2013; 70:3907-27. [PMID: 23479131 PMCID: PMC11113817 DOI: 10.1007/s00018-013-1303-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/29/2013] [Accepted: 02/14/2013] [Indexed: 12/20/2022]
Abstract
The ability to regenerate injured or lost body parts has been an age-old ambition of medical science. In contrast to humans, teleost fish and urodele amphibians can regrow almost any part of the body with seeming effortlessness. Retinoic acid is a molecule that has long been associated with these impressive regenerative capacities. The discovery 30 years ago that addition of retinoic acid to regenerating amphibian limbs causes "super-regeneration" initiated investigations into the presumptive roles of retinoic acid in regeneration of appendages and other organs. However, the evidence favoring or dismissing a role for endogenous retinoids in regeneration processes remained sparse and ambiguous. Now, the availability of genetic tools to manipulate and visualize the retinoic acid signaling pathway has opened up new routes to dissect its roles in regeneration. Here, we review the current understanding on endogenous functions of retinoic acid in regeneration and discuss key questions to be addressed in future research.
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Affiliation(s)
- Nicola Blum
- Developmental Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Gerrit Begemann
- Developmental Biology, University of Bayreuth, 95440 Bayreuth, Germany
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Kedishvili NY. Enzymology of retinoic acid biosynthesis and degradation. J Lipid Res 2013; 54:1744-60. [PMID: 23630397 PMCID: PMC3679379 DOI: 10.1194/jlr.r037028] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/17/2013] [Indexed: 12/18/2022] Open
Abstract
All-trans-retinoic acid is a biologically active derivative of vitamin A that regulates numerous physiological processes. The concentration of retinoic acid in the cells is tightly regulated, but the exact mechanisms responsible for this regulation are not completely understood, largely because the enzymes involved in the biosynthesis of retinoic acid have not been fully defined. Recent studies using in vitro and in vivo models suggest that several members of the short-chain dehydrogenase/reductase superfamily of proteins are essential for retinoic acid biosynthesis and the maintenance of retinoic acid homeostasis. However, the exact roles of some of these recently identified enzymes are yet to be characterized. The properties of the known contributors to retinoid metabolism have now been better defined and allow for more detailed understanding of their interactions with retinoid-binding proteins and other retinoid enzymes. At the same time, further studies are needed to clarify the interactions between the cytoplasmic and membrane-bound proteins involved in the processing of hydrophobic retinoid metabolites. This review summarizes current knowledge about the roles of various biosynthetic and catabolic enzymes in the regulation of retinoic acid homeostasis and outlines the remaining questions in the field.
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Affiliation(s)
- Natalia Y Kedishvili
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Cai AQ, Radtke K, Linville A, Lander AD, Nie Q, Schilling TF. Cellular retinoic acid-binding proteins are essential for hindbrain patterning and signal robustness in zebrafish. Development 2012; 139:2150-5. [PMID: 22619388 DOI: 10.1242/dev.077065] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The vitamin A derivative retinoic acid (RA) is a morphogen that patterns the anterior-posterior axis of the vertebrate hindbrain. Cellular retinoic acid-binding proteins (Crabps) transport RA within cells to both its nuclear receptors (RARs) and degrading enzymes (Cyp26s). However, mice lacking Crabps are viable, suggesting that Crabp functions are redundant with those of other fatty acid-binding proteins. Here we show that Crabps in zebrafish are essential for posterior patterning of the hindbrain and that they provide a key feedback mechanism that makes signaling robust as they are able to compensate for changes in RA production. Of the four zebrafish Crabps, Crabp2a is uniquely RA inducible and depletion or overexpression of Crabp2a makes embryos hypersensitive to exogenous RA. Computational models confirm that Crabp2a improves robustness within a narrow concentration range that optimizes a 'robustness index', integrating spatial information along the RA morphogen gradient. Exploration of signaling parameters in our models suggests that the ability of Crabp2a to transport RA to Cyp26 enzymes for degradation is a major factor in promoting robustness. These results demonstrate a previously unrecognized requirement for Crabps in RA signaling and hindbrain development, as well as a novel mechanism for stabilizing morphogen gradients despite genetic or environmental fluctuations in morphogen availability.
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Affiliation(s)
- Anna Q Cai
- Department of Mathematics, University of California Irvine, Irvine, CA 92697, USA
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Everts HB. Endogenous retinoids in the hair follicle and sebaceous gland. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1821:222-9. [PMID: 21914489 PMCID: PMC3237781 DOI: 10.1016/j.bbalip.2011.08.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 08/12/2011] [Accepted: 08/29/2011] [Indexed: 12/19/2022]
Abstract
Vitamin A and its derivatives (retinoids) are critically important in the development and maintenance of multiple epithelial tissues, including skin, hair, and sebaceous glands, as shown by the detrimental effects of either vitamin A deficiency or toxicity. Thus, precise levels of retinoic acid (RA, active metabolite) are needed. These precise levels of RA are achieved by regulating several steps in the conversion of dietary vitamin A (retinol) to RA and RA catabolism. This review discusses the localization of RA synthesis to specific sites within the hair follicle and sebaceous gland, including their stem cells, during both homeostasis and disease states. It also discusses what is known about the specific roles of RA within the hair follicle and sebaceous gland. This article is part of a Special Issue entitled: Retinoid and Lipid Metabolism.
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Affiliation(s)
- Helen B Everts
- Department of Human Nutrition, The Oio State University, 350 Campell Hall, 1787 Neil Ave, Columbus, OH 43210, USA.
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McNeilly AD, Woods JA, Ibbotson SH, Wolf CR, Smith G. Characterization of a human keratinocyte HaCaT cell line model to study the regulation of CYP2S1. Drug Metab Dispos 2011; 40:283-9. [PMID: 22039172 DOI: 10.1124/dmd.111.042085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CYP2S1 is an extrahepatic cytochrome P450 (P450) that shows marked individuality in constitutive and inducible expression. CYP2S1 mRNA expression is increased in psoriasis and by treatments for psoriasis, including retinoids and UV radiation, although endogenous substrates remain poorly characterized. Because previous model systems have overexpressed modified CYP2S1 in bacteria, human HaCaT keratinocyte cells were screened for constitutive and regulatable CYP2S1 expression and CYP2S1 activity in HaCaT cells compared with a novel Chinese hamster ovary (CHO)-based cell line engineered to stably coexpress CYP2S1 and NADPH cytochrome P450 reductase. Constitutive mRNA expression for CYP2S1 and additional P450s, retinoid acid receptors (RARα, RARβ, RARγ), and retinoid X receptors (RXRα, RXRβ and RXRγ) was assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis in HaCaT cells. Cells were then exposed to retinoids or to UV radiation (UVR), and changes in CYP2S1 mRNA abundance were further examined by qRT-PCR analysis. P450 expression in HaCaT cells was similar to human skin, with abundant CYP2S1 expression. RARα and RARγ (but not RARβ) and all RXR isoforms were also detectable. All-trans retinoic acid (atRA) induced CYPS1 mRNA expression more potently than 9-cis RA or 13-cis RA. P450-dependent atRA metabolism was demonstrated in HaCaT cells, with a very similar metabolite profile to that produced by our CYP2S1-expressing CHO cells. CYP2S1 mRNA expression was also induced by UVR, more potently than CYP1B1, a known UVR-inducible P450. Our results demonstrate regulatable and functional CYP2S1 expression in HaCaT cells, thus identifying a human cell line model with utility for further analysis of CYP2S1 regulation and substrate specificity.
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Affiliation(s)
- Alison D McNeilly
- Centre for Neuroscience, Division of Medical Sciences, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
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Topletz AR, Thatcher JE, Zelter A, Lutz JD, Tay S, Nelson WL, Isoherranen N. Comparison of the function and expression of CYP26A1 and CYP26B1, the two retinoic acid hydroxylases. Biochem Pharmacol 2011; 83:149-63. [PMID: 22020119 DOI: 10.1016/j.bcp.2011.10.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 10/06/2011] [Accepted: 10/07/2011] [Indexed: 10/16/2022]
Abstract
All-trans-retinoic acid (atRA) is an important signaling molecule in all chordates. The cytochrome P450 enzymes CYP26 are believed to partially regulate cellular concentrations of atRA via oxidative metabolism and hence affect retinoid homeostasis and signaling. CYP26A1 and CYP26B1 are atRA hydroxylases that catalyze formation of similar metabolites in cell systems. However, they have only 40% sequence similarity suggesting differences between the two enzymes. The aim of this study was to determine whether CYP26A1 and CYP26B1 have similar catalytic activity, form different metabolites from atRA and are expressed in different tissues in adults. The mRNA expression of CYP26A1 and CYP26B1 correlated between human tissues except for human cerebellum in which CYP26B1 was the predominant CYP26 and liver in which CYP26A1 dominated. Quantification of CYP26A1 and CYP26B1 protein in human tissues was in agreement with the mRNA expression and showed correlation between the two isoforms. Qualitatively, recombinant CYP26A1 and CYP26B1 formed the same primary and sequential metabolites from atRA. Quantitatively, CYP26B1 had a lower K(m) (19nM) and V(max) (0.8 pmol/min/pmol) than CYP26A1 (K(m)=50 nM and V(max)=10 pmol/min/pmol) for formation of 4-OH-RA. The major atRA metabolites 4-OH-RA, 18-OH-RA and 4-oxo-RA were all substrates of CYP26A1 and CYP26B1, and CYP26A1 had a 2-10-fold higher catalytic activity towards all substrates tested. This study shows that CYP26A1 and CYP26B1 are qualitatively similar RA hydroxylases with overlapping expression profiles. CYP26A1 has higher catalytic activity than CYP26B1 and seems to be responsible for metabolism of atRA in tissues that function as a barrier for atRA exposure.
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Affiliation(s)
- Ariel R Topletz
- Department of Pharmaceutics, University of Washington, Seattle, United States
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Napoli JL. Physiological insights into all-trans-retinoic acid biosynthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:152-67. [PMID: 21621639 DOI: 10.1016/j.bbalip.2011.05.004] [Citation(s) in RCA: 245] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/05/2011] [Accepted: 05/12/2011] [Indexed: 01/25/2023]
Abstract
All-trans-retinoic acid (atRA) provides essential support to diverse biological systems and physiological processes. Epithelial differentiation and its relationship to cancer, and embryogenesis have typified intense areas of interest into atRA function. Recently, however, interest in atRA action in the nervous system, the immune system, energy balance and obesity has increased considerably, especially concerning postnatal function. atRA action depends on atRA biosynthesis: defects in retinoid-dependent processes increasingly relate to defects in atRA biogenesis. Considerable evidence indicates that physiological atRA biosynthesis occurs via a regulated process, consisting of a complex interaction of retinoid binding-proteins and retinoid recognizing enzymes. An accrual of biochemical, physiological and genetic data have identified specific functional outcomes for the retinol dehydrogenases, RDH1, RDH10, and DHRS9, as physiological catalysts of the first step in atRA biosynthesis, and for the retinal dehydrogenases RALDH1, RALDH2, and RALDH3, as catalysts of the second and irreversible step. Each of these enzymes associates with explicit biological processes mediated by atRA. Redundancy occurs, but seems limited. Cumulative data support a model of interactions among these enzymes with retinoid binding-proteins, with feedback regulation and/or control by atRA via modulating gene expression of multiple participants. The ratio apo-CRBP1/holo-CRBP1 participates by influencing retinol flux into and out of storage as retinyl esters, thereby modulating substrate to support atRA biosynthesis. atRA biosynthesis requires the presence of both an RDH and an RALDH: conversely, absence of one isozyme of either step does not indicate lack of atRA biosynthesis at the site. This article is part of a Special Issue entitled: Retinoid and Lipid Metabolism.
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Thatcher JE, Zelter A, Isoherranen N. The relative importance of CYP26A1 in hepatic clearance of all-trans retinoic acid. Biochem Pharmacol 2010; 80:903-12. [PMID: 20513361 DOI: 10.1016/j.bcp.2010.05.023] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 05/19/2010] [Accepted: 05/19/2010] [Indexed: 11/26/2022]
Abstract
All-trans retinoic acid (RA) is a critical signaling molecule and its concentration is tightly regulated. Several P450 enzymes including CYP26A1, CYP2C8, and CYP3A4 have been proposed to be responsible for RA clearance in the liver but their quantitative importance has not been demonstrated. To determine the contribution of CYP26A1 to hepatic clearance of RA, CYP26A1 protein was quantified in 37 human liver microsomes (HLMs). CYP26A1 expression ranged from not detectable to 2.80pmol/mg microsomal protein. RA clearance by P450 enzymes abundant in human liver was measured in Supersomes. CYP2C8, CYP3A4, CYP3A5 and CYP3A7 metabolized RA with unbound K(m) values of 3.4-7.2microM and V(max) values of 2.3-4.9pmol/min/pmol P450, but were less efficient than CYP26A1 in clearing RA. Simulations performed for livers with varying P450 expression levels over a range of RA concentrations demonstrated that at both endogenous and therapeutic concentrations of RA, CYP26A1 is the primary enzyme responsible for 4-OH RA formation clearance. HLM incubation data showed that 4-OH RA formation velocity varied from 0.2 to 15.3pmol/min/mg microsomal protein and velocity in HLMs was significantly correlated (p<0.01) to CYP26A1, CYP3A4, and CYP3A5 protein content, but not to CYP2C8. When experimental data were scaled to in vivo clearances, the predicted hepatic clearance of RA (0.07L/min using combined Supersome data) was similar to the published in vivo clearance of RA. These findings suggest that CYP26A1 is the P450 isoform that should be targeted when designing RA metabolism blocking agents.
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Affiliation(s)
- Jayne E Thatcher
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA 98195, United States
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Abstract
Retinoic acid (RA) is a critical signaling molecule that regulates gene transcription and the cell cycle. Understanding of RA signaling has increased dramatically over the past decades, but the connection between whole body RA homeostasis and gene regulation in individual cells is still unclear. It has been proposed that cytochrome P450 family 26 (CYP26) enzymes have a role in determining the cellular exposure to RA by inactivating RA in cells that do not need RA. The CYP26 enzymes have been shown to metabolize RA efficiently and they are also inducible by RA in selected systems. However, their expression patterns in different cell types and a mechanistic understanding of their function is still lacking. Based on preliminary kinetic data and protein expression levels, one may predict that if CYP26A1 is expressed in the liver at even very low levels, it will be the major RA hydroxylase in this tissue. As such, it is an attractive pharmacological target for drug development when one aims to increase circulating or cellular RA concentrations. To further the understanding of how CYP26 enzymes contribute to the regulation of RA homeostasis, structural information of the CYP26s, commercially available recombinant enzymes and good specific and sensitive antibodies are needed.
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Affiliation(s)
- Jayne E. Thatcher
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA, USA
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White RJ, Schilling TF. How degrading: Cyp26s in hindbrain development. Dev Dyn 2008; 237:2775-90. [PMID: 18816852 DOI: 10.1002/dvdy.21695] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The vitamin A derivative retinoic acid performs many functions in vertebrate development and is thought to act as a diffusible morphogen that patterns the anterior-posterior axis of the hindbrain. Recent work in several systems has led to insights into how the spatial distribution of retinoic acid is regulated. These have shown local control of synthesis and degradation, and computational models suggest that degradation by the Cyp26 enzymes plays a critical role in the formation of a morphogen gradient as well as its ability to compensate for fluctuations in RA levels.
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Affiliation(s)
- Richard J White
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
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Verfaille CJ, Borgers M, van Steensel MAM. Retinoic acid metabolism blocking agents (RAMBAs): a new paradigm in the treatment of hyperkeratotic disorders. J Dtsch Dermatol Ges 2007; 6:355-64. [PMID: 17941881 DOI: 10.1111/j.1610-0387.2007.06541.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Synthetic vitamin A derivatives, retinoids,have long been the mainstay of treatment for several disorders of keratinization, notably the ichthyoses and severe acne. Some forms of psoriasis also respond well. Their considerable power comes at a price. They have dose-limiting side effects and can be highly teratogenic, limiting their use in women of childbearing age.Thus, retinoids are used less often than their potential would warrant. However, the recent development of compounds that block the catabolism of endogenous vitamin A, called Retinioic Acid Metabolism Blocking Agents or RAMBAs, offers new possibilities. With these drugs, retinoid effects with less side effects and a reduction of the post-treatment teratogenicity period due to their favourable pharmacokinetic profile might be expected. In this review, we discuss how retinoids work, how they are metabolized and how RAMBAs influence this process. We also review the presently available data from clinical trials with RAMBAs.
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Affiliation(s)
- Christel J Verfaille
- Barrier Therapeutics NV, Geel, Belgium, and Department of Dermatology, University Hospital Maastricht, The Netherlands
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37
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Propping C, Mönig B, Luksch H, Mey J. Distribution of the cellular retinoic acid binding protein CRABP-I in the developing chick optic tectum. Brain Res 2007; 1168:21-31. [PMID: 17706616 DOI: 10.1016/j.brainres.2007.06.089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 06/18/2007] [Accepted: 06/19/2007] [Indexed: 11/22/2022]
Abstract
Vitamin A is a major morphogen for the visual system. Most of its effects are mediated by retinoic acid (RA), whose developmental functions include pattern formation, neuronal differentiation and possibly axonal guidance. Although RA has been suggested to regulate development of the retina and its central projection, little is known about the distribution of retinoid receptors and binding proteins in the optic tectum, which in birds is the direct target of most retinofugal axons. We investigated the spatial and temporal distribution of the cellular retinoic acid binding protein-I (CRABP-I) in the chick midbrain. While the precise role of CRABP-I is still unknown, this is an intracellular transport protein for RA, which tends to be expressed in cells that are responsive to retinoic acid. Our data show immunoreactivity of CRABP-I in the tectal anlage at E2.5 and during the entire period of embryonic development. It was found in differentiating neurons of the generative zone, in migrating cells of the prospective stratum griseum et fibrosum superficiale and in mature neurons in this layer. In addition, we detected retinoid receptors RARalpha, RARbeta, RXRalpha, RXRbeta and RXRgamma in the developing tectum. Cell culture experiments demonstrate CRABP-I expression in a subpopulation of tectal neurons as they differentiate in vitro. These results are consistent with a regulatory role of RA in tectal neurogenesis and physiology.
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Affiliation(s)
- Corinna Propping
- Institut für Biologie II, RWTH Aachen, Kopernikusstrasse 16, 52056 Aachen, Germany
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38
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Tang XH, Vivero M, Gudas LJ. Overexpression of CRABPI in suprabasal keratinocytes enhances the proliferation of epidermal basal keratinocytes in mouse skin topically treated with all-trans retinoic acid. Exp Cell Res 2007; 314:38-51. [PMID: 17727842 DOI: 10.1016/j.yexcr.2007.07.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 07/16/2007] [Accepted: 07/16/2007] [Indexed: 12/31/2022]
Abstract
We investigated whether ectopic expression of CRABPI, a cellular retinoic acid binding protein, influenced the actions of all-trans retinoic acid (ATRA) in transgenic (TG) mice. We targeted CRABPI to the basal vs. suprabasal layers of mouse epidermis by using the keratin 14 (K14) and keratin 10 (K10) promoters, respectively. Greater CRABPI protein levels were detected in the epidermis of adult transgenic(+) mice than in transgenic(-) mice for both transgenes. In adult mouse skin CRABPI overexpression in the basal or suprabasal keratinocytes did not cause morphological abnormalities, but did result in decreased CRABPII mRNA levels. Ectopically overexpressed CRABPI in suprabasal keratinocytes, but not in basal keratinocytes, enhanced the thickening of the epidermis induced by topical ATRA treatments (10 microM, 400 microl for 4 days) by 1.59+/-0.2-fold (p<0.05). ATRA treatment (10 microM) resulted in a 59.9+/-9.8% increase (p<0.05) in the BrdU labeling index in K10/FLAG-CRABPI TG(+) mice vs. TG(-) mice. Retinoid topical treatments reduced p27 and CYP26A1 mRNA levels in TG(+) and TG(-) mouse skin in K14 and K10/FLAG-CRABPI transgenic mice. As epidermal basal keratinocyte proliferation is stimulated by paracrine growth factors secreted by ATRA activated suprabasal keratinocytes, our results indicate that CRABPI overexpression in suprabasal keratinocytes enhances the physiological functions of ATRA.
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Affiliation(s)
- Xiao-Han Tang
- Department of Pharmacology, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10021, USA
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Hsia E, Johnston MJ, Houlden RJ, Chern WH, Hofland HEJ. Effects of topically applied acitretin in reconstructed human epidermis and the rhino mouse. J Invest Dermatol 2007; 128:125-30. [PMID: 17637822 DOI: 10.1038/sj.jid.5700968] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oral acitretin is currently indicated for the treatment of severe psoriasis in adults, but its use is limited by systemic side effects and teratogenicity. Topical administration of acitretin may lessen the risk of systemic toxicity while increasing local bioavailability in the skin. The effects of topical acitretin on reconstructed human epidermis (RHE) and Rhino mice were investigated and compared to those of currently marketed topical retinoids: tretinoin and tazarotene. In acitretin-treated RHE cultures, there was a reduction in keratohyalin granules and filaggrin expression in the stratum granulosum, a loss of keratin 10 expression in the stratum spinosum, and an increase in keratin 19 expression in all viable cell layers. All retinoids showed similar signs of activity in RHE cultures. Furthermore, the release of pro-inflammatory cytokines IL-1alpha and IL-8 in RHE cultures was less pronounced with acitretin compared to tretinoin- and tazarotene-containing formulations, suggesting that acitretin may be less irritating. In Rhino mice, acitretin induced a local, dose-dependent reduction in utricle diameter after seven daily dermal doses. A similar effect was observed in tretinoin- and tazarotene-treated mice. Our data suggest that topical application of acitretin may have a therapeutic benefit in the local management of keratinization disorders.
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Affiliation(s)
- Edward Hsia
- Center for Skin Biology, Stiefel Laboratories Inc., Palo Alto, California 94304, USA
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Hu P, Zhang M, Napoli JL. Ontogeny of rdh9 (Crad3) expression: ablation causes changes in retinoid and steroid metabolizing enzymes, but RXR and androgen signaling seem normal. Biochim Biophys Acta Gen Subj 2006; 1770:694-705. [PMID: 17270348 PMCID: PMC1847623 DOI: 10.1016/j.bbagen.2006.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2006] [Revised: 12/12/2006] [Accepted: 12/13/2006] [Indexed: 11/30/2022]
Abstract
Crad3 (cis-retinol/androgen dehydrogenase 3), a short-chain dehydrogenase/reductase, converts 9-cis-retinol into 9-cis-retinal and 3alpha-androstanediol into dihydrotestosterone. Crad3 may serve in biosynthesis of 9-cis-retinoic acid, a putative RXR ligand, and/or regeneration of potent androgens. RT-PCR showed that expression of the gene that encodes Crad3, rdh9, begins in liver by e11.5, and in kidney, testis, brain and intestine during e15.5-e16.5. In situ hybridization showed rdh9 expression in embryonic liver, ganglia, small intestine, lung, skin and vertebral cartilage. In adult, in situ hybridization revealed rdh9 expression intensely in hepatocytes, weakly in kidney glomerulus, and intensely in collecting tubules. In intestine, undifferentiated epithelia had greater expression than differentiated epithelia at the distal villus end. Testes expressed rdh9 in spermatogonia, and weakly in Leydig cells. Adult brain expressed rdh9 in the dentate gyrus and CA regions of the hippocampus, the cerebellum Purkinje cells, and the glomerular and mitral cell layers of the olfactory bulb. Rdh9-null mice, backcrossed against C57BL/6J mice, were born in Mendelian frequency, were healthy and fertile, and had normal tissue retinoid and serum dihydrotestosterone levels. Expression of rdh1, a gene that encodes an efficient retinol dehydrogenase, decreased 3- to 8-fold in rdh9-null mice, depending on dietary vitamin A. Microarray analysis and quantitative PCR revealed 2- to 4-fold increases in mRNA of enzymes that catalyze xenobiotic and steroid metabolism, including Cyp2, Cyp3, 11beta-hydroxysteroid dehydrogenase type 2, and 17beta-hydroxsteroid dehydrogenases types 4 and 5. These data indicate widespread Crad3 function(s) in steroid and/or retinoid metabolism starting mid embryogenesis.
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Affiliation(s)
| | | | - Joseph L. Napoli
- Address reprint requests to: Joseph L. Napoli, 119 Morgan Hall, MC#3104, University of California, Berkeley, CA 94720, Phone: 510-642-5202, FAX: 510-642-0535,
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Levadoux-Martin M, Li Y, Blackburn A, Chabanon H, Hesketh JE. Perinuclear localisation of cellular retinoic acid binding protein I mRNA. Biochem Biophys Res Commun 2006; 340:326-31. [PMID: 16376305 DOI: 10.1016/j.bbrc.2005.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Accepted: 12/02/2005] [Indexed: 11/23/2022]
Abstract
Retinoids are important metabolic and developmental regulators that act through nuclear receptors. The cellular retinoic acid binding protein CRABPI has been suggested to play a role in trafficking of retinoic acid but its exact functions and subcellular localisation remain unclear. Here we show that in CHO cells both exogenous CRABPI transcripts and tagged CRABPI protein have a perinuclear distribution that depends upon the 3'UTR of the mRNA. The CRABPI 3'UTR conferred perinuclear localisation on globin reporter transcripts. Deletion analysis indicated that the first 123nt of CRABPI 3'UTR are necessary for localisation of both CRABPI mRNA and protein. We propose that CRABPI mRNA is localised by a signal within its 3'UTR and that this partly determines the distribution of CRABPI protein.
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Affiliation(s)
- M Levadoux-Martin
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle-upon-Tyne, UK
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Lefebvre P, Martin PJ, Flajollet S, Dedieu S, Billaut X, Lefebvre B. Transcriptional activities of retinoic acid receptors. VITAMINS AND HORMONES 2005; 70:199-264. [PMID: 15727806 DOI: 10.1016/s0083-6729(05)70007-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vitamin A derivatives plays a crucial role in embryonic development, as demonstrated by the teratogenic effect of either an excess or a deficiency in vitamin A. Retinoid effects extend however beyond embryonic development, and tissue homeostasis, lipid metabolism, cellular differentiation and proliferation are in part controlled through the retinoid signaling pathway. Retinoids are also therapeutically effective in the treatment of skin diseases (acne, psoriasis and photoaging) and of some cancers. Most of these effects are the consequences of retinoic acid receptors activation, which triggers transcriptional events leading either to transcriptional activation or repression of retinoid-controlled genes. Synthetic molecules are able to mimic part of the biological effects of the natural retinoic acid receptors, all-trans retinoic acid. Therefore, retinoic acid receptors are considered as highly valuable therapeutic targets and limiting unwanted secondary effects due to retinoid treatment requires a molecular knowledge of retinoic acid receptors biology. In this review, we will examine experimental evidence which provide a molecular basis for the pleiotropic effects of retinoids, and emphasize the crucial roles of coregulators of retinoic acid receptors, providing a conceptual framework to identify novel therapeutic targets.
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Affiliation(s)
- Philippe Lefebvre
- INSERM U459 and Ligue Nationale Contre le Cancer, Faculté de Médecine de Lille, 59045 Lille cedex, France
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Ross AC, Zolfaghari R. Regulation of hepatic retinol metabolism: perspectives from studies on vitamin A status. J Nutr 2004; 134:269S-275S. [PMID: 14704332 DOI: 10.1093/jn/134.1.269s] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Liver vitamin A (retinol) is obtained from several sources and is subject to multiple fates. Lecithin:retinol acyltransferase (LRAT), a microsomal enzyme present in liver and several other retinol-metabolizing tissues, esterifies retinol that is associated with a cellular retinol-binding protein, CRBP or CRBP-II. Recent research has shown that LRAT mRNA expression and enzyme activity are regulated in a tissue-specific manner. In vitamin A-deficient liver, both LRAT mRNA and activity are significantly down-regulated as well as rapidly induced after the administration of vitamin A or its principal hormonal metabolite, retinoic acid (RA). In long-term feeding studies and the metabolic steady state, liver LRAT is expressed dose-dependently across a wide range of dietary vitamin A. Additionally, an RA-inducible cytochrome P450, P450RAI or CYP26, is down-regulated in liver during vitamin A deficiency and up-regulated dose-dependently by dietary vitamin A and exogenous RA. Based on these results, we propose that LRAT and CYP26 serve as two molecular mechanisms, coordinately regulated by all-trans-RA, to control the availability of retinol and RA, respectively. The LRAT reaction, besides providing a readily retrievable storage form of vitamin A, may regulate the availability of retinol to other pathways, while the CYP26 reaction may serve to prevent a detrimental "overshoot" of RA concentration. Moreover, retinoid metabolism in the liver is likely to be closely integrated with that in peripheral tissues through the rapid interorgan transfer and recycling of retinoids, affecting the whole-body economy of vitamin A.
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Affiliation(s)
- A Catharine Ross
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
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Chen AC, Yu K, Lane MA, Gudas LJ. Homozygous deletion of the CRABPI gene in AB1 embryonic stem cells results in increased CRABPII gene expression and decreased intracellular retinoic acid concentration. Arch Biochem Biophys 2003; 411:159-73. [PMID: 12623064 DOI: 10.1016/s0003-9861(02)00732-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cellular retinoic acid (RA) binding proteins I and II (CRABPI and CRABPII), intracellular proteins which bind retinoic acid with high affinity, are involved in the actions of RA, though their exact roles are not fully understood. We have generated several genetically engineered AB1 cell lines in which both alleles of the CRABPI gene have been deleted by homologous recombination. We have used these CRABPI knockout cell lines to examine the consequences of functional loss of CRABPI on RA-induced gene expression and RA metabolism in the murine embryonic stem cell line, AB1, which undergoes differentiation in response to RA. Complete lack of CRABPI results in decreased intracellular [3H]RA concentrations under conditions in which external concentrations of [3H]RA are low (1-10nM) and in an altered distribution of [3H] polar metabolites of [3H]RA in the cell and in the medium. Fewer [3H] polar metabolites are retained within the CRABPI(-/-) cells compared to the wild-type cells. These data suggest that CRABPI functions to regulate the intracellular concentrations of retinoic acid and to maintain high levels of oxidized retinoic acid metabolites such as 4-oxoretinoic acid within cells.
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Affiliation(s)
- Anne C Chen
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10021, USA
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Abstract
Since the late 1980s, there has been an explosion of information on the molecular mechanisms and functions of vitamin A. This review focuses on the essential role of vitamin A in female reproduction and embryonic development and the metabolism of vitamin A (retinol) that results in these functions. Evidence strongly supports that in situ-generated all-trans retinoic acid (atRA) is the functional form of vitamin A in female reproduction and embryonic development. This is supported by the ability to reverse most reproductive and developmental blocks found in vitamin A deficiency with atRA, the block in embryonic development that occurs in retinaldehyde dehydrogenase type 2 null mutant mice, and the essential roles of the retinoic acid receptors, at least in embryogenesis. Early studies of embryos from marginally vitamin A-deficient (VAD) pregnant rats revealed a collection of defects called the vitamin A-deficiency syndrome. The manipulation of all-trans retinoic acid (atRA) levels in the diet of VAD female rats undergoing a reproduction cycle has proved to be an important new tool in deciphering the points of atRA function in early embryos and has provided a means to generate large numbers of embryos at later stages of development with the vitamin A-deficiency syndrome. The essentiality of the retinoid receptors in mediating the activity of atRA is exemplified by the many compound null mutant embryos that now recapitulate both the original vitamin A-deficiency syndrome and exhibit a host of new defects, many of which can also be observed in the VAD-atRA-supported rat embryo model and in retinaldehyde dehydrogenase type 2 (RALDH2) mutant mice. A major task for the future is to elucidate the atRA-dependent pathways that are normally operational in vitamin A-sufficient animals and that are perturbed in deficiency, thus leading to the characteristic VAD phenotypes described above.
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Affiliation(s)
- Margaret Clagett-Dame
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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Chithalen JV, Luu L, Petkovich M, Jones G. HPLC-MS/MS analysis of the products generated from all-trans-retinoic acid using recombinant human CYP26A. J Lipid Res 2002; 43:1133-42. [PMID: 12091498 DOI: 10.1194/jlr.m100343-jlr200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two mammalian hCYP26A expression systems have been used to analyze the metabolic products of CYP26A. Through the use of extensive HPLC, UV spectroscopy, and liquid chromatography/tandem mass spectrometry (LC-MS/MS) methodology, we have conclusively demonstrated that the complex mixture of products comprises 4-OH-all-trans-retinoic acid, 4-oxo-all-trans-retinoic acid, and 18-OH-all-trans-retinoic acid, and more polar products, partially identified as dihydroxy and mono-oxo, mono-hydroxy derivatives. These more polar products are presumed to result from multiple hydroxylations on the beta-ionone ring. The inter-relationship of initial and polar metabolites was inferred from both gene-dose and time-course experiments. Both initial and secondary metabolic steps after 4-oxo-all-trans-retinoic acid are ketoconazole-sensitive, suggesting that steps in the production of water-soluble metabolites are cytochrome P450-dependent.
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Affiliation(s)
- James V Chithalen
- Department of Biochemistry, Queen's University, Kingston, ON, K7L 3N6, Canada
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Radominska-Pandya A, Chen G. Photoaffinity labeling of human retinoid X receptor beta (RXRbeta) with 9-cis-retinoic acid: identification of phytanic acid, docosahexaenoic acid, and lithocholic acid as ligands for RXRbeta. Biochemistry 2002; 41:4883-90. [PMID: 11939783 DOI: 10.1021/bi0121151] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We utilized [20-methyl-(3)H]-9-cis-retinoic acid ([(3)H]9-cis-RA) as a direct photoaffinity probe for the characterization of human recombinant retinoid X receptor beta protein (RXRbeta). The photoaffinity labeling was light- and concentration-dependent, saturable, and protected by unlabeled 9-cis-RA in a concentration-dependent manner, indicating that binding occurred in the RXR retinoid binding site. all-trans-Retinoic acid (atRA) did not affect labeling with the 9-cis derivative, confirming that atRA does not compete for the 9-cis-RA binding site. Several retinoid, fatty acid, and bile acid ligands were evaluated for their ability to recognize the 9-cis-RA binding site. Retinol, atRA glucuronide, 13-cis-RA, dolichol, 5,6-epoxy-RA, and vitamin D(3) did not compete for the 9-cis-RA binding site. However, the saturated diterpenoid phytanic acid (PA) and docosahexaenoic acid, which have been recently shown to activate the nuclear receptor, RXR, competed with 9-cis-RA labeling, showing high affinity for the 9-cis-RA binding site. Oleic acid, arachidonic acid, and butyric acid did not interact. However, the bile acid lithocholic acid competed efficiently with 9-cis-RA for the binding site. These data validated the photoaffinity assay as an excellent system for the identification and evaluation of ligands for RXR.
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Affiliation(s)
- Anna Radominska-Pandya
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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Martinez-Ceballos E, Burdsal CA. Differential expression of chicken CYP26 in anterior versus posterior limb bud in response to retinoic acid. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2001; 290:136-47. [PMID: 11471143 DOI: 10.1002/jez.1043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Multiple studies indicate that quantitative control of the levels of all-trans-retinoic acid (RA) in the vertebrate embryo is necessary for correct development. The function of RA in cells is regulated by a number of coordinated mechanisms. One of those mechanisms involves controls on the rate of RA catabolism. Recently, enzymes capable of catabolizing RA were found to constitute a new family, called CYP26, within the cytochrome P450 superfamily. CYP26 homologues have been isolated from human, mouse, zebra fish, and recently from the chick. In this study, we examined the regulation of chicken CYP26 (cCYP26) expression by RA during the early phase of chick limb outgrowth. In the anterior limb mesenchyme and apical ectodermal ridge (AER), cCYP26 expression was induced in a concentration dependent manner by implanting beads soaked in 0.1, 1, and 5 mg/ml RA. The RA-induced expression of cCYP26 in anterior limb mesenchyme and the AER was detected as early as 1 hr after treatment and was not affected by the presence of cycloheximide. In contrast to the anterior limb, the induction of cCYP26 was dramatically reduced (or absent) when RA beads were implanted in the posterior limb mesenchyme. Furthermore, induction of cCYP26 expression in the anterior mesenchyme was inhibited by transplantations of the zone of polarizing activity (ZPA) and by Shh-soaked beads. Our data suggest that different mechanisms regulate retinoid homeostasis in the AER and mesenchyme during limb bud outgrowth. J. Exp. Zool. 290:136-147, 2001.
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Affiliation(s)
- E Martinez-Ceballos
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA 70118, USA
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Radominska-Pandya A, Chen G, Samokyszyn VM, Little JM, Gall WE, Zawada G, Terrier N, Magdalou J, Czernik P. Application of photoaffinity labeling with [(3)H] all trans- and 9-cis-retinoic acids for characterization of cellular retinoic acid--binding proteins I and II. Protein Sci 2001; 10:200-11. [PMID: 11266607 PMCID: PMC2249844 DOI: 10.1110/ps.26501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2000] [Revised: 11/01/2000] [Accepted: 11/01/2000] [Indexed: 10/14/2022]
Abstract
Cellular retinoic acid-binding proteins (CRABPs) are carrier proteins thought to play a crucial role in the transport and metabolism of all-trans-retinoic acid (atRA) and its derivatives within the cell. This report describes a novel photoaffinity-based binding assay involving competition between potential ligands of CRABP and [(3)H]atRA or [(3)H]-9-cis-RA for binding to the atRA-binding sites of CRABP I and II. Photoaffinity labeling of purified CRABPs with [(3)H]atRA was light- and concentration-dependent, saturable, and protected by several retinoids in a concentration-dependent manner, indicating that binding occurred in the CRABP atRA-binding site. Structure-function relationship studies demonstrated that oxidative changes to the atRA beta-ionone ring did not affect ligand potency. However, derivatives lacking a terminal carboxyl group and some cis isomers did not bind to CRABPs. These studies also identified two novel ligands for CRABPs: 5,6-epoxy-RA and retinoyl-beta-D-glucuronide (RAG). The labeling of both CRABPs with 9-cis-RA occurred with much lower affinity. Experimental evidence excluded nonspecific binding of RAG to CRABPs and UDP-glucuronosyltransferases, the enzymes responsible for RAG synthesis. These results established that RAG is an effective ligand of CRABPs. Therefore, photoaffinity labeling with [(3)H]atRA can be used to identify new ligands for CRABP and retinoid nuclear receptors and also provide information concerning the identity of amino acid(s) localized in the atRA-binding site of these proteins.
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Key Words
- cellular retinoic acid-binding protein
- photoaffinity labeling
- all-trans-retinoic acid
- 9-cis-retinoic acid
- retinoic acid glucuronide
- 5,6-epoxy-retinoic acid
- crabp, cellular retinoic acid–binding protein
- atra, all-trans-retinoic acid
- rar, nuclear retinoic acid receptor
- rxr, nuclear retinoid receptor
- 13-cis-ra, 13-cis-retinoic acid
- 9-cis-ra, 9-cis-retinoic acid
- 4-oh-ra, 4-hydroxy-all-trans-retinoic acid
- roh, all-trans-retinol
- roac, all-trans-retinyl acetate
- 5,6-epoxy-ra, 5,6-epoxy-all-trans-ra
- kpfg, ketoprofen glucuronide
- la, lithocholic acid
- lag, lithocholic acid glucuronide
- rag, retinoic acid glucuronide
- ugt, udp-glucuronosyltransferase
- udp-glcua, udp-glucuronic acid
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Affiliation(s)
- A Radominska-Pandya
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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Abstract
We report that immunohistochemical staining for cellular retinoic acid-binding protein (CRABP) was restricted to the cytoplasm of cortical cells in bovine adrenal. In contrast, staining for the similar protein, cellular retinol-binding protein (CRBP), was found throughout these cells. After transfections of CRABP and CRBP into cultured cells, immunofluorescence analyses again revealed cytoplasmic restriction only for CRABP, with a pronounced punctate appearance. Use of organelle-specific fluorochromes indicated that CRABP immunofluorescence overlaid exactly with the pattern of the mitochondrial-specific fluorochrome. Confirmation of this association came with subcellular fractionation of the adrenal cortex. CRABP, but not CRBP, co-sedimented with the mitochondria, a novel finding for a member of this superfamily of cellular lipid-binding proteins.
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Affiliation(s)
- S J Ruff
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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