scholarly journals Retinoic Acid Receptor α Function in Vertebrate Limb Skeletogenesis: a Modulator of Chondrogenesis

1997 ◽  
Vol 136 (2) ◽  
pp. 445-457 ◽  
Author(s):  
David E. Cash ◽  
Cheryl B. Bock ◽  
Klaus Schughart ◽  
Elwood Linney ◽  
T. Michael Underhill
Keyword(s):  
Retinoic Acid ◽  
Limb Development ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Transgenic Animals ◽  
Large Degree ◽  
All Trans Retinoic Acid ◽  
Chondrogenic Phenotype ◽  
Mouse Limb ◽  
Retinoic Acid Receptor Α

Retinoic acid is a signaling molecule involved in the regulation of growth and morphogenesis during development. There are three types of nuclear receptors for all-trans retinoic acid in mammals, RARα, RARβ, and RARγ, which transduce the retinoic acid signal by inducing or repressing the transcription of target genes (Leid, M., P. Kastner, and P. Chambon. 1992. Trends Biochem. Sci. 17:427–433). While RARα, RARβ, and RARγ are expressed in distinct but overlapping patterns in the developing mouse limb, their exact role in limb development remains unclear. To better understand the role of retinoic acid receptors in mammalian limb development, we have ectopically expressed a modified RARα with constitutive activity (Balkan, W., G.K. Klintworth, C.B. Bock, and E. Linney. 1992. Dev. Biol. 151:622–625) in the limbs of transgenic mice. Overexpression of the transgene was associated with marked pre- and postaxial limb defects, particularly in the hind limb, where expression of the transgene was consistently seen across the whole anteroposterior axis. The defects displayed in these mice recapitulate, to a large degree, many of the congenital limb malformations observed in the fetuses of dams administered high doses of retinoic acid (Kochhar, D.M. 1973. Teratology. 7:289–295). Further analysis of these transgenic animals showed that the defect in skeletogenesis resided at the level of chondrogenesis. Comparison of the expression of the transgene relative to that of endogenous RARα revealed that downregulation of RARα is important in allowing the chondrogenic phenotype to be expressed. These results demonstrate a specific function for RARα in limb development and the regulation of chondroblast differentiation.

scholarly journals Comprehensive genomic screens identify a role for PLZF-RARα as a positive regulator of cell proliferation via direct regulation of c-MYC

Blood ◽  
2009 ◽  
Vol 114 (27) ◽  
pp. 5499-5511 ◽  
Author(s):  
Kim L. Rice ◽  
Itsaso Hormaeche ◽  
Sergei Doulatov ◽  
Jared M. Flatow ◽  
David Grimwade ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Promyelocytic Leukemia ◽  
Dominant Negative ◽  
Myeloid Leukemias ◽  
Direct Target ◽  
Retinoic Acid Receptor Α ◽  
Chip Chip

Abstract The t(11;17)(q23;q21) translocation is associated with a retinoic acid (RA)–insensitive form of acute promyelocytic leukemia (APL), involving the production of reciprocal fusion proteins, promyelocytic leukemia zinc finger–retinoic acid receptor α (PLZF-RARα) and RARα-PLZF. Using a combination of chromatin immunoprecipitation promotor arrays (ChIP-chip) and gene expression profiling, we identify novel, direct target genes of PLZF-RARα that tend to be repressed in APL compared with other myeloid leukemias, supporting the role of PLZF-RARα as an aberrant repressor in APL. In primary murine hematopoietic progenitors, PLZF-RARα promotes cell growth, and represses Dusp6 and Cdkn2d, while inducing c-Myc expression, consistent with its role in leukemogenesis. PLZF-RARα binds to a region of the c-MYC promoter overlapping a functional PLZF site and antagonizes PLZF-mediated repression, suggesting that PLZF-RARα may act as a dominant-negative version of PLZF by affecting the regulation of shared targets. RA induced the differentiation of PLZF-RARα–transformed murine hematopoietic cells and reduced the frequency of clonogenic progenitors, concomitant with c-Myc down-regulation. Surviving RA-treated cells retained the ability to be replated and this was associated with sustained c-Myc expression and repression of Dusp6, suggesting a role for these genes in maintaining a self-renewal pathway triggered by PLZF-RARα.

Mutation of Cellular Retinoic Acid-Binding Protein-II (Crabp-II) Does Not Account for Resistance to All-Trans Retinoic Acid (ATRA) in Relapse Acute Promyelocytic Leukemia (APL).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2081-2081
Author(s):  
Binu-John Sankoorikal ◽  
Da-Cheng Zhou ◽  
Peter H. Wiernik ◽  
Robert E. Gallagher
Keyword(s):  
Retinoic Acid ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Treated Patient ◽  
Coding Region ◽  
Treatment Regimens ◽  
All Trans Retinoic Acid ◽  
Negative Role ◽  
Multiple Relapse ◽  
Crabp Ii

Abstract An increase in CRABP-II has frequently been invoked as a cause of resistance to ATRA in APL due to cytoplasmic sequestration and catabolism of ATRA. However, recent evidence indicates that CRABP-II has a positive rather than a negative role in ATRA activity by facilitating delivery of ATRA to retinoic acid receptor-alpha (RARα) associated with ATRA target genes in the cell nucleus or/and by serving as a co-activator of RARα-regulated transcription. This implies that if CRABP-II has a role in the development of ATRA resistance in APL, this would more likely occur through a deficiency rather than from an increase in CRABP-II. We previously reported that CRABP-II is constitutively expressed at similar levels in pretreatment and relapse APL cells (Zhou, et al, Cancer Res58, 5770, 1998), suggesting that putative CRABP-II deficiency is not due to the loss of CRABP-II expression. To investigate the alternative possibility that CRABP-II deficiency might arise through inactivating mutations, we sequenced the entire coding region of CRABP-II from 18 cases of APL who had relapsed from prior ATRA-containing treatment regimens. In 8 cases RNA was transcribed by reverse transcriptase to cDNA and amplified by polymerase chain reaction (PCR), using primers anchored in the 5′ and 3′ untranslated region of mRNA; in 10 cases, genomic DNA was PCR amplified for sequence analysis, using primers anchored in the introns between the 4 exons of the gene. No CRABP-II mutations were identified. The samples tested included 11 first-relapse cases, 2 of whom were refractory to reinduction therapy with intravenous liposomal-ATRA, and 7 multiple relapse cases, all of whom were clinically refractory to ATRA and had, additionally, relapsed from arsenic trioxide therapy. Also, no mutations were found in 3 APL patients who had relapsed from chemotherapy-induced remissions or in 3 APL cell lines (NB4, UF-1 and AP-1060). Two heterozygous base substitutions were incidentally identified in CRABP-II intron 2 in a chemotherapy-only treated patient. These results indicate that CRABP-II mutations rarely, if ever, contribute to ATRA-resistance or disease relapse in APL.

scholarly journals Ligands and DNA in the allosteric control of retinoid receptors function

2021 ◽  
Author(s):  
Pierre Germain ◽  
Natacha Rochel ◽  
William Bourguet
Keyword(s):  
Retinoic Acid ◽  
Dna Sequences ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Signal Propagation ◽  
Retinoid Receptors ◽  
Allosteric Control ◽  
Current State ◽  
All Trans Retinoic Acid ◽  
Structural Mechanisms

Abstract Retinoids are a family of compounds that include both vitamin A (all-trans retinol) and its naturally occurring metabolites such as retinoic acids (e.g. all-trans retinoic acid) as well as synthetic analogs. They are critically involved in the regulation of a wide variety of essential biological processes, such as embryogenesis and organogenesis, apoptosis, reproduction, vision, and the growth and differentiation of normal and neoplastic cells in vertebrates. The ability of these small molecules to control the expression of several hundred genes through binding to nuclear ligand-dependent transcription factors accounts for most of their functions. Three retinoic acid receptor (RARα,β,γ) and three retinoid X receptor (RXRα,β,γ) subtypes form a variety of RXR–RAR heterodimers that have been shown to mediate the pleiotropic effects of retinoids through the recruitment of high-molecular weight co-regulatory complexes to response-element DNA sequences found in the promoter region of their target genes. Hence, heterodimeric retinoid receptors are multidomain entities that respond to various incoming signals, such as ligand and DNA binding, by allosteric structural alterations which are the basis of further signal propagation. Here, we provide an overview of the current state of knowledge with regard to the structural mechanisms by which retinoids and DNA response elements act as allosteric effectors that may combine to finely tune RXR–RAR heterodimers activity.

scholarly journals Characterization of the Retinoid Binding Properties of the Major Fusion Products Present in Acute Promyelocytic Leukemia Cells

Blood ◽  
1997 ◽  
Vol 90 (3) ◽  
pp. 1175-1185 ◽  
Author(s):  
Laura Benedetti ◽  
Arthur A. Levin ◽  
Bianca M. Scicchitano ◽  
Francesco Grignani ◽  
Gary Allenby ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Acute Promyelocytic Leukemia ◽  
Transcriptional Activation ◽  
Retinoic Acid Receptor ◽  
Promyelocytic Leukemia ◽  
Binding Assays ◽  
Binding Properties ◽  
All Trans Retinoic Acid ◽  
Structural And Functional Properties ◽  
Retinoic Acid Receptor Α

Abstract The bcr1- and bcr3- promyelocytic leukemia/retinoic acid receptor α (PML/RARα) are the two major fusion proteins expressed in acute promyelocytic leukemia (APL) patients. These proteins, which are present in different lengths of PML (amino acids 1-552 and 1-394, respectively), contain most of the functional domains of PML and RARα, bind all-trans-retinoic acid (t-RA), and act as t-RA–dependent transcription factors. T-RA is an effective inducer of clinical remission only in patients carrying the t(15; 17) and expressing the PML/RARα products. However, in APL patients achieving complete remission with t-RA therapy the bcr3-PML/RARα product has been found associated with a poorer prognosis than bcr1-PML/RARα. In the present study we have investigated the structural and functional properties of the bcr3-PML/RARα in comparison to the previously characterized bcr1-PML/RARα. In particular, we have measured the binding properties of the two endogenous ligands t-RA and 9-cis-RA to both of these isoforms. T-RA binding analysis of nuclear and cytosolic extracts prepared from bcr3-PML/RARα APL patients and from bcr3-PML/RARα COS-1 transfected cells indicates that this protein is present only as high-molecular-weight nuclear complexes. Using saturation binding assays and Scatchard analyses we found that t-RA binds with slightly less affinity to the bcr3-PML/RARα receptor than to bcr1-PML/RARα or RARα (Kd = 0.4 nmol/L, 0.13 nmol/L or 0.09 nmol/L, respectively). Moreover, two different high-affinity 9-cis-RA binding sites (Kd = 0.45 and 0.075 nmol/L) were detectable in the bcr3-PML/RARα product but not in the bcr1-PML/RARα product (Kd = 0.77 nmol/L). By competition binding experiments we showed that 9-cis-RA binds with higher specificity to the bcr3-PML/RARα isoform than to the bcr1-PML/RARα or RARα. Consistent with these data, the binding of 9-cis-RA to the bcr3-PML/RARα product resulted in increased transcriptional activation of the RA-responsive element (RARE) TRE, but not of the βRARE, in transiently transfected COS-1 cells. These results provide evidence indicating that preferential retinoid binding to the different PML/RARα products can be measured.

Enhancement of the inducible NO synthase activation by retinoic acid is mimicked by RARα agonist in vivo

2002 ◽  
Vol 283 (3) ◽  
pp. E525-E535 ◽  
Author(s):  
Carole Seguin-Devaux ◽  
Yvan Devaux ◽  
Véronique Latger-Cannard ◽  
Sandrine Grosjean ◽  
Cécile Rochette-Egly ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Retinoic Acid Receptor ◽  
Interferon Γ ◽  
Relative Contribution ◽  
All Trans Retinoic Acid ◽  
X Receptors ◽  
Retinoic Acid Receptor Α ◽  
Nitrite Nitrate ◽  
Plasma Nitrite

We have previously shown that all- trans retinoic acid (atRA), the active metabolite of vitamin A, enhances the activation of the inducible nitric oxide synthase (NOS II) pathway, a component of innate immunity, in rats in vivo. We investigated the relative contribution of retinoic acid receptor-α (RARα) and retinoid X receptors (RXRs) to NOS II activation triggered by LPS. Five-day supplementation with 10 mg/kg of either atRA or the RARα selective agonist Ro-40-6055, but not with 10 mg/kg of the pan-RXR agonist Ro-25-7386, enhanced the LPS-induced NOS II mRNA, protein expression in liver, and plasma nitrite/nitrate concentration. Both atRA and the RARα agonist (but not the RXR agonist) increased the number of peripheral T helper lymphocytes and plasma interferon-γ concentration. Synergism between retinoids and LPS on NOS II activation within an organ coincided with synergism on interferon regulatory factor-1 mRNA expression but not with the level of expression of the RARα protein. These results suggest that, in vivo, atRA activates NOS II through RARα and contributes to characterizing the complex effect of retinoids on the host inflammatory/immune response.

scholarly journals All-trans-Retinoic Acid Represses Obesity and Insulin Resistance by Activating both Peroxisome Proliferation-Activated Receptor β/δ and Retinoic Acid Receptor

2009 ◽  
Vol 29 (12) ◽  
pp. 3286-3296 ◽  
Author(s):  
Daniel C. Berry ◽  
Noa Noy
Keyword(s):  
Insulin Resistance ◽  
Retinoic Acid ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Biological Activities ◽  
In Vivo Studies ◽  
Peroxisome Proliferation ◽  
The Metabolic Syndrome ◽  
All Trans Retinoic Acid

ABSTRACT Many biological activities of all-trans-retinoic acid (RA) are mediated by the ligand-activated transcription factors termed retinoic acid receptors (RARs), but this hormone can also activate the nuclear receptor peroxisome proliferation-activated receptor β/δ (PPARβ/δ). We show here that adipocyte differentiation is accompanied by a shift in RA signaling which, in mature adipocytes, allows RA to activate both RARs and PPARβ/δ, thereby enhancing lipolysis and depleting lipid stores. In vivo studies using a dietary-induced mouse model of obesity indicated that onset of obesity is accompanied by downregulation of adipose PPARβ/δ expression and activity. RA treatment of obese mice induced expression of PPARβ/δ and RAR target genes involved in regulation of lipid homeostasis, leading to weight loss and improved insulin responsiveness. RA treatment also restored adipose PPARβ/δ expression. The data indicate that suppression of obesity and insulin resistance by RA is largely mediated by PPARβ/δ and is further enhanced by activation of RARs. By targeting two nuclear receptors, RA may be a uniquely efficacious agent in the therapy and prevention of the metabolic syndrome.

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