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1
Baleato, R. M., R. J. Aitken, and S. D. Roman. "244.Interaction between bone morphogenetic protein 4 and retinoid signalling in mouse spermatogenesis." Reproduction, Fertility and Development 16, no. 9 (2004): 244. http://dx.doi.org/10.1071/srb04abs244.
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Vitamin A (retinol, or ROL) is also essential for normal spermatogenesis in the rat and mouse. Vitamin A-deficient (VAD) rodents suffer various disorders including blindness and male infertility. The molecular mechanisms leading to infertility in vitamin A deficient rodents have never been fully elucidated. Following prolonged vitamin A withdrawal the only germ cells remaining in the VAD rodent testis are stem cell spermatogonia, type A1 spermatogonia, and a few preleptotene spermatocytes. Supplementing the diet of these animals with retinoic acid (RA) alleviates all symptoms of vitamin A deficiency, with the exception of sight and spermatogenesis. It is not until VAD animals are re-administered ROL through the diet, or RA is injected in repeated high doses directly into the testis, that normal spermatogenic function is restored. Here we report an interaction, in germ cells, between the Bone Morphogenetic Protein (BMP) 4 and retinoid signalling pathways that may help explain the molecular mechanics of vitamin A deficiency. We localised BMP4 gene expression to adult germ cells, in particular spermatogonia, at both the mRNA and protein level. We generated VAD mice and found that in the absence of retinoids in vivo, bmp4 gene expression was significantly upregulated in the testis. We also observed that the expression of bmp4 is downregulated by retinoid treatment in germ cells isolated from vitamin A sufficient mice. Expression of bmp4 mRNA in isolated spermatogonia was more sensitive to ROL rather than RA. Our results may reflect a direct requirement for ROL by germ cells for the resumption of spermatogenesis in VAD animals that involves the regulation of BMP4 expression. Furthermore our observations suggest that retinoid signalling in germ cells is different to that observed in somatic cells, and may provide insights into the role of retinoids in spermatogenesis.
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Ruberte, E., V. Friederich, P. Chambon, and G. Morriss-Kay. "Retinoic acid receptors and cellular retinoid binding proteins. III. Their differential transcript distribution during mouse nervous system development." Development 118, no. 1 (May 1, 1993): 267–82. http://dx.doi.org/10.1242/dev.118.1.267.
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We have studied the transcript distribution of the retinoic acid receptors (RARs) and the cytoplasmic retinoid binding proteins during embryonic development of the mouse nervous system. Of the three retinoic acid receptors, only RAR-gamma was not expressed in developing neural structures. RAR-beta and RAR-alpha both showed rostral limits of expression in the medulla oblongata equivalent to their patterns of expression in the neuroepithelium of the early hindbrain neural tube. Within their expression domains in the spinal cord and brain, RAR-alpha was ubiquitously expressed, whereas RAR-beta transcripts showed very specific patterns of expression, suggesting that this receptor is involved in mediating retinoic acid-induced gene expression in relation to the development of specific neural structures or pathways. The cytoplasmic binding proteins, cellular retinoic acid binding proteins type I and II (CRABP I and CRABP II) and cellular retinol binding protein type I (CRBP I), were widely distributed in developing neural structures. Their differential spatiotemporal patterns of expression suggest that fine regional control of availability of retinoic acid (RA) to the nuclear receptors plays an important role in organization and differentiation of the nervous system. For instance, expression of CRABP I in the migrating cells that give rise to the olivary and pontine nuclei, which develop abnormally in conditions of retinoid excess, is consistent with observations from a variety of other systems indicating that CRABP I limits the access of RA to the nuclear receptors in normal physiological conditions. Similarly, expression of CRBP I in the choroid plexuses, which develop abnormally in conditions of vitamin A deficiency, is consistent with observations indicating that this binding protein mediates the synthesis of RA in tissues requiring high levels of RA for their normal developmental programme. RAR-beta and CRABP II, which are both RA-inducible, were coexpressed with CRBP I in the choroid plexus and in many other sites, perhaps reflecting the fact that all three genes are RA-inducible. The function of CRABP II is not well understood; its domains of expression showed overlaps with both CRABP I and CRBP I.
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Leszczyński, Paweł, Magdalena Śmiech, Aamir Salam Teeli, Effi Haque, Robert Viger, Hidesato Ogawa, Mariusz Pierzchała, and Hiroaki Taniguchi. "Deletion of the Prdm3 Gene Causes a Neuronal Differentiation Deficiency in P19 Cells." International Journal of Molecular Sciences 21, no. 19 (September 29, 2020): 7192. http://dx.doi.org/10.3390/ijms21197192.
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PRDM (PRDI-BF1 (positive regulatory domain I-binding factor 1) and RIZ1 (retinoblastoma protein-interacting zinc finger gene 1) homologous domain-containing) transcription factors are a group of proteins that have a significant impact on organ development. In our study, we assessed the role of Prdm3 in neurogenesis and the mechanisms regulating its expression. We found that Prdm3 mRNA expression was induced during neurogenesis and that Prdm3 gene knockout caused premature neuronal differentiation of the P19 cells and enhanced the growth of non-neuronal cells. Interestingly, we found that Gata6 expression was also significantly upregulated during neurogenesis. We further studied the regulatory mechanism of Prdm3 expression. To determine the role of GATA6 in the regulation of Prdm3 mRNA expression, we used a luciferase-based reporter assay and found that Gata6 overexpression significantly increased the activity of the Prdm3 promoter. Finally, the combination of retinoic acid receptors α and β, along with Gata6 overexpression, further increased the activity of the luciferase reporter. Taken together, our results suggest that in the P19 cells, PRDM3 contributed to neurogenesis and its expression was stimulated by the synergism between GATA6 and the retinoic acid signaling pathway.
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Hu, Qi-Xin, Hui-Yi Wang, Lu Jiang, Chen-Yu Wang, Lin-Gao Ju, Yuan Zhu, Bo Zhong, Min Wu, Zhen Wang, and Lian-Yun Li. "Histone demethylase LSD1 promotes RIG-I poly-ubiquitination and anti-viral gene expression." PLOS Pathogens 17, no. 9 (September 16, 2021): e1009918. http://dx.doi.org/10.1371/journal.ppat.1009918.
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Under RNA virus infection, retinoic acid-inducible gene I (RIG-I) in host cells recognizes viral RNA and activates the expression of type I IFN. To investigate the roles of protein methyltransferases and demethylases in RIG-I antiviral signaling pathway, we screened all the known related enzymes with a siRNA library and identified LSD1 as a positive regulator for RIG-I signaling. Exogenous expression of LSD1 enhances RIG-I signaling activated by virus stimulation, whereas its deficiency restricts it. LSD1 interacts with RIG-I, promotes its K63-linked polyubiquitination and interaction with VISA/MAVS. Interestingly, LSD1 exerts its function in antiviral response not dependent on its demethylase activity but through enhancing the interaction between RIG-I with E3 ligases, especially TRIM25. Furthermore, we provide in vivo evidence that LSD1 increases antiviral gene expression and inhibits viral replication. Taken together, our findings demonstrate that LSD1 is a positive regulator of signaling pathway triggered by RNA-virus through mediating RIG-I polyubiquitination.
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Husson, Marianne, Valérie Enderlin, Serge Alfos, Catherine Féart, Paul Higueret, and Véronique Pallet. "Triiodothyronine administration reverses vitamin A deficiency-related hypo-expression of retinoic acid and triiodothyronine nuclear receptors and of neurogranin in rat brain." British Journal of Nutrition 90, no. 1 (July 2003): 191–98. http://dx.doi.org/10.1079/bjn2003877.
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Recent studies have revealed that retinoids play an important role in the adult central nervous system and cognitive functions. Previous investigations in mice have shown that vitamin A deficiency (VAD) generates a hypo-expression of retinoic acid (RA, the active metabolite of vitamin A) receptors and of neurogranin (RC3, a neuronal protein involved in synaptic plasticity) and a concomitant selective behavioural impairment. Knowing that RC3 is both a triiodothyronine (T3) and a RA target gene, and in consideration of the relationships between the signalling pathways of retinoids and thyroid hormones, the involvement of T3 on RA signalling functionality in VAD was investigated. Thus, the effects of vitamin A depletion and subsequent administration with RA and/or T3 on the expression of RA nuclear receptors (RAR, RXR), T3 nuclear receptor (TR) and on RC3 in the brain were examined. Rats fed a vitamin A-deficient diet for 10 weeks exhibited a decreased expression of RAR, RXR and TR mRNA and of RC3 mRNA and proteins. RA administration to these vitamin A-deficient rats reversed only the RA hypo-signalling in the brain. Interestingly, T3 is able to restore its own brain signalling simultaneously with that of vitamin A and the hypo-expression of RC3. These results obtained in vivo revealed that one of the consequences of VAD is a dysfunction in the thyroid signalling pathway in the brain. This seems of crucial importance since the down regulation of RC3 observed in the depleted rats was corrected only by T3.
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Chen, W. H., G. M. Morriss-Kay, and A. J. Copp. "Genesis and prevention of spinal neural tube defects in the curly tail mutant mouse: involvement of retinoic acid and its nuclear receptors RAR-beta and RAR-gamma." Development 121, no. 3 (March 1, 1995): 681–91. http://dx.doi.org/10.1242/dev.121.3.681.
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A role for all-trans-retinoic acid in spinal neurulation is suggested by: (1) the reciprocal domains of expression of the retinoic acid receptors RAR-beta and RAR-gamma in the region of the closed neural tube and open posterior neuropore, respectively, and (2) the preventive effect of maternally administered retinoic acid (5 mg/kg) on spinal neural tube defects in curly tail (ct/ct) mice. Using in situ hybridisation and computerised image analysis we show here that in ct/ct embryos, RAR-beta transcripts are deficient in the hindgut endoderm, a tissue whose proliferation rate is abnormal in the ct mutant, and RAR-gamma transcripts are deficient in the tail bud and posterior neuropore region. The degree of deficiency of RAR-gamma transcripts is correlated with the severity of delay of posterior neuropore closure. As early as 2 hours following RA treatment at 10 days 8 hours post coitum, i.e. well before any morphogenetic effects are detectable, RAR-beta expression is specifically upregulated in the hindgut endoderm, and the abnormal expression pattern of RAR-gamma is also altered. These results suggest that the spinal neural tube defects which characterise the curly tail phenotype may be due to interaction between the ct gene product and one or more aspects of the retinoic acid signalling pathway.
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Deis, Jessica A., Hong Guo, Yingjie Wu, Chengyu Liu, David A. Bernlohr, and Xiaoli Chen. "Lipocalin 2 regulates retinoic acid-induced activation of beige adipocytes." Journal of Molecular Endocrinology 61, no. 3 (October 2018): 115–26. http://dx.doi.org/10.1530/jme-18-0017.
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Lipocalin-2 (LCN2) has been previously characterized as an adipokine regulating thermogenic activation of brown adipose tissue and retinoic acid (RA)-induced thermogenesis in mice. The objective of this study was to explore the role and mechanism for LCN2 in the recruitment and retinoic acid-induced activation of brown-like or ‘beige’ adipocytes. We found LCN2 deficiency reduces key markers of thermogenesis including uncoupling protein-1 (UCP1) and peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) in inguinal white adipose tissue (iWAT) and inguinal adipocytes derived from Lcn2 −/− mice. Lcn2 −/− inguinal adipocytes have attenuated insulin-induced upregulation of thermogenic gene expression and p38 mitogen-activated protein kinase (p38MAPK) signaling pathway activation. This is accompanied by a lower basal and maximal oxidative capacity in Lcn2 −/− inguinal adipocytes, indicating mitochondrial dysfunction. Recombinant Lcn2 was able to restore insulin-induced p38MAPK phosphorylation in both WT and Lcn2 −/− inguinal adipocytes. Rosiglitazone treatment during differentiation of Lcn2 −/− adipocytes is able to recruit beige adipocytes at a normal level, however, further activation of beige adipocytes by insulin and RA is impaired in the absence of LCN2. Further, the synergistic effect of insulin and RA on UCP1 and PGC-1α expression is markedly reduced in Lcn2 −/− inguinal adipocytes. Most intriguingly, LCN2 and the retinoic acid receptor-alpha (RAR-α) are concurrently translocated to the plasma membrane of adipocytes in response to insulin, and this insulin-induced RAR-α translocation is absent in adipocytes deficient in LCN2. Our data suggest a novel LCN2-mediated pathway by which RA and insulin synergistically regulates activation of beige adipocytes via a non-genomic pathway of RA action.
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Tamblyn, J. A., L. E. Jeffery, R. Susarla, D. M. Lissauer, S. L. Coort, A. Muñoz Garcia, K. Knoblich, et al. "Transcriptomic analysis of vitamin D responses in uterine and peripheral NK cells." Reproduction 158, no. 2 (August 2019): 213–23. http://dx.doi.org/10.1530/rep-18-0509.
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Vitamin D deficiency is prevalent in pregnant women and is associated with adverse pregnancy outcomes, in particular disorders of malplacentation. The active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), is a potent regulator of innate and adaptive immunity, but its immune effects during pregnancy remain poorly understood. During early gestation, the predominant immune cells in maternal decidua are uterine natural killer cells (uNK), but the responsivity of these cells to 1,25(OH)2D3 is unknown despite high levels of 1,25(OH)2D3 in decidua. Transcriptomic responses to 1,25(OH)2D3 were characterised in paired donor uNK and peripheral natural killer cells (pNK) following cytokine (CK) stimulation. RNA-seq analyses indicated 911 genes were differentially expressed in CK-stimulated uNK versus CK-stimulated pNK in the absence of 1,25(OH)2D3, with predominant differentially expressed pathways being associated with glycolysis and transforming growth factor β (TGFβ). RNA-seq also showed that the vitamin D receptor (VDR) and its heterodimer partner retinoid X receptor were differentially expressed in CK-stimulated uNK vs CK-stimulated pNK. Further analyses confirmed increased expression of VDR mRNA and protein, as well as VDR-RXR target in CK-stimulated uNK. RNA-seq analysis showed that in CK-stimulated pNK, 1,25(OH)2D3 induced 38 and suppressed 33 transcripts, whilst in CK-stimulated uNK 1,25(OH)2D3 induced 46 and suppressed 19 genes. However, multiple comparison analysis of transcriptomic data indicated that 1,25(OH)2D3 had no significant overall effect on gene expression in either CK-stimulated pNK or uNK. These data indicate that CK-stimulated uNK are transcriptionally distinct from pNK and, despite expressing abundant VDR, neither pNK nor uNK are sensitive targets for vitamin D.
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Lefebvre, Bruno, Céline Brand, Sébastien Flajollet, and Philippe Lefebvre. "Down-Regulation of the Tumor Suppressor Gene Retinoic Acid Receptor β2 through the Phosphoinositide 3-Kinase/Akt Signaling Pathway." Molecular Endocrinology 20, no. 9 (September 1, 2006): 2109–21. http://dx.doi.org/10.1210/me.2005-0321.
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Abstract The retinoic acid receptor β2 (RARβ2) is a potent, retinoid-inducible tumor suppressor gene, which is a critical molecular relay for retinoid actions in cells. Its down-regulation, or loss of expression, leads to resistance of cancer cells to retinoid treatment. Up to now, no primary mechanism underlying the repression of the RARβ2 gene expression, hence affecting cellular retinoid sensitivity, has been identified. Here, we demonstrate that the phosphoinositide 3-kinase/Akt signaling pathway affects cellular retinoid sensitivity, by regulating corepressor recruitment to the RARβ2 promoter. Through direct phosphorylation of the corepressor silencing mediator for retinoic and thyroid hormone receptors (SMRT), Akt stabilized RAR/SMRT interaction, leading to an increased tethering of SMRT to the RARβ2 promoter, decreased histone acetylation, down-regulation of the RARβ2 expression, and impaired cellular differentiation in response to retinoid. The phosphoinositide 3-kinase/Akt signaling pathway, an important modulator of cellular survival, has thus a direct impact on cellular retinoid sensitivity, and its deregulation may be the triggering event in retinoid resistance of cancer cells.
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Orozco Reina Agustina, Agüero Rocio, Razzeto Gabriela, Gimenez Maria Sofia, and Vasquez Gomez Miriam Ester. "Alterations in oxidative metabolism in liver of female rats: Effects of long-term vitamin A deficiency." GSC Biological and Pharmaceutical Sciences 13, no. 1 (November 30, 2020): 267–78. http://dx.doi.org/10.30574/gscbps.2020.13.1.0064.
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Background: The latest estimate by 5 UN agencies is that 821 million people globally are undernourished, which puts them at risk of vitamin and other nutrient deficiencies. Vitamin A deficiency remains a widespread public health problem among women and children in the developing world the role of vitamin A and its active metabolites in pathways involved in antioxidant protection and in the inhibition of important pathways that promote oxidative stress. Objectives: Determine if vitamin A deficiency could influence oxidative metabolism in 6-month-old female wistar rats. Materials and Methods: Determine the concentration of carbonyl proteins, as a marker of protein oxidation; TBARS, as a lipoperoxidation marker; and nitrotyrosine as a marker of oxidative stress dependent on nitric oxide. Quantify the expression of CAT, SOD, eNOS and iNOS in the liver and wistar rats deficient in vitamin A for 6 months. Results: An increase in the concentration of carbonyl protein and nitrotyrosine in the liver tissue deficient in vitamin A is observed. The expression of SOD, eNOS and iNOS decreased in the group with a private diet of vitamin A. From the regression analysis a positive correlation was established between hepatic retinoic acid levels and gene expression of eNOS, iNOS and SOD. A positive correlation between serum retinoic acid levels and gene expression of eNOS and iNOS was also observed. Conclusions: It is possible to ratify the relationship between the development of stress and vitamin A levels; improving the understanding of hepatic metabolism and its response to the absence of this vitamin.
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Ross, Alexander W., Catriona A. Webster, Julian G. Mercer, Kim M. Moar, Francis J. Ebling, Sandrine Schuhler, Perry Barrett, and Peter J. Morgan. "Photoperiodic Regulation of Hypothalamic Retinoid Signaling: Association of Retinoid X Receptor γ with Body Weight." Endocrinology 145, no. 1 (January 1, 2004): 13–20. http://dx.doi.org/10.1210/en.2003-0838.
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Abstract This study reports novel events related to photoperiodic programming of the neuroendocrine hypothalamus. To investigate photoperiod-responsive genes, Siberian hamsters were maintained in long or short photoperiods that generate physiological states of obesity or leanness. Microarray expression analysis first identified CRBP1 as a photoperiod-responsive gene, and then further studies using in situ hybridization and immunocytochemistry revealed that expression levels of several related retinoid-signaling genes were modulated in response to photoperiod changes. Genes of the retinoid-signaling pathway, encoding nuclear receptors (RXR/RAR) and retinoid binding proteins (CRBP1 and CRABP2) are photoperiodically regulated in the dorsal tuberomamillary nucleus (DTM): Their expression is significantly lower in short photoperiods and parallels body weight decreases. Studies in pinealectomized hamsters confirm that the pineal melatonin rhythm is necessary for these seasonal changes, and studies in testosterone-treated hamsters reveal that these changes in gene expression are not the secondary consequence of photoperiod-induced changes in steroid levels. Comparative studies using Syrian hamsters, which show divergent seasonal body weight responses to Siberian hamsters when exposed to short photoperiods, showed a distinct pattern of changes in retinoid gene expression in the DTM in response to a change in photoperiod. We infer that the DTM may be an important integrating center for photoperiodic control of seasonal physiology and suggest that the changes in retinoid X receptor γ expression may be associated with seasonal changes in body weight and energy metabolism.
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Mehta, Kapil, Teresa McQueen, Taghi Manshouri, Michael Andreeff, Steven Collins, and Maher Albitar. "Involvement of Retinoic Acid Receptor-α–Mediated Signaling Pathway in Induction of CD38 Cell-Surface Antigen." Blood 89, no. 10 (May 15, 1997): 3607–14. http://dx.doi.org/10.1182/blood.v89.10.3607.
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Abstract Human leukocyte antigen CD38, a 45-kD single-chain, transmembrane glycoprotein, is a bifunctional ectoenzyme that participates in signal transduction pathways involved in the regulation of cell growth and differentiation. In this study, we demonstrate the nature of retinoid receptors involved in retinoic acid–induced expression of CD38 protein in the human myeloblastic leukemia cell line HL-60. We used a variant HL-60 cell line, HL-60R, in which retinoid receptor function has been abrogated by a trans-dominant negative mutation. We introduced the normal retinoic acid receptors (RAR)-α, -β, and -γ or retinoid X receptor (RXR)-α into HL-60R cells by retroviral vector-mediated gene transfer. Based on experiments using these cell lines and receptor-specific synthetic retinoids that preferentially bind to one of the RARs or RXRs, we conclude that RAR-α is involved in retinoid-induced CD38 expression in HL-60 cells. Further evidence included our demonstration that blocking of RAR-α with the antagonist Ro 41-5253 completely suppressed the retinoid-induced expression of CD38 mRNA transcript and the production of CD38 protein in HL-60 cells. Various tissues from transgenic mice that expressed an antisense construct of RAR-α lacked or produced very low levels of CD38. As expected, the tissues from transgenic mice contained 50% to 80% reduced levels of RAR-α. These results suggest that regulation of CD38 expression, both in vitro and in vivo, is under the direct control of RAR-α retinoid receptors.
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Mehta, Kapil, Teresa McQueen, Taghi Manshouri, Michael Andreeff, Steven Collins, and Maher Albitar. "Involvement of Retinoic Acid Receptor-α–Mediated Signaling Pathway in Induction of CD38 Cell-Surface Antigen." Blood 89, no. 10 (May 15, 1997): 3607–14. http://dx.doi.org/10.1182/blood.v89.10.3607.3607_3607_3614.
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Human leukocyte antigen CD38, a 45-kD single-chain, transmembrane glycoprotein, is a bifunctional ectoenzyme that participates in signal transduction pathways involved in the regulation of cell growth and differentiation. In this study, we demonstrate the nature of retinoid receptors involved in retinoic acid–induced expression of CD38 protein in the human myeloblastic leukemia cell line HL-60. We used a variant HL-60 cell line, HL-60R, in which retinoid receptor function has been abrogated by a trans-dominant negative mutation. We introduced the normal retinoic acid receptors (RAR)-α, -β, and -γ or retinoid X receptor (RXR)-α into HL-60R cells by retroviral vector-mediated gene transfer. Based on experiments using these cell lines and receptor-specific synthetic retinoids that preferentially bind to one of the RARs or RXRs, we conclude that RAR-α is involved in retinoid-induced CD38 expression in HL-60 cells. Further evidence included our demonstration that blocking of RAR-α with the antagonist Ro 41-5253 completely suppressed the retinoid-induced expression of CD38 mRNA transcript and the production of CD38 protein in HL-60 cells. Various tissues from transgenic mice that expressed an antisense construct of RAR-α lacked or produced very low levels of CD38. As expected, the tissues from transgenic mice contained 50% to 80% reduced levels of RAR-α. These results suggest that regulation of CD38 expression, both in vitro and in vivo, is under the direct control of RAR-α retinoid receptors.
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Murphy, Philip T., Gary Lynch, Stephen Bergin, John Quinn, Siobhan Glavey, Philip W. Murphy, and Paul Kennedy. "Strong Correlation Between CTLA-4 and LEF1 Gene Expression Levels in CLL: Targeting of the Wnt/β-Catenin Pathway May Adversely Affect CTLA-4 Expression and Function." Blood 128, no. 22 (December 2, 2016): 5571. http://dx.doi.org/10.1182/blood.v128.22.5571.5571.
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Abstract Recently published clinical trials have confirmed the effectiveness of anti-CD38 monoclonal antibody therapy in myeloma. Furthermore, in vitro studies of chronic lymphocytic leukaemia (CLL) cells suggest that CD38 expression can be enhanced by treatment with retinoid derivatives and thus may enhance the cytotoxic effects of anti-CD38 therapy. However, retinoids have been shown to have diverse effects on cellular function and we have previously shown that the retinoid drug acitretin upregulates CD38 expression while also reducing cell homing to the chemokine CXCL12 in primary CLL cells. To investigate possible key mechanisms for these effects, we purified CD20+ B cells from the peripheral blood of 20 CLL patients (9 previously treated, 11 untreated) and, using flow cytometry, measured percentage cell surface expression of CD38 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4, CD152). We also measured gene expression levels of the key retinoid receptor, stimulated by retinoic acid 6 (STRA6) and it's agonist, retinol-binding protein 4 (RBP4), as well as CTLA-4, cyclin D1 (CCND1) and the transcription factors, lymphoid enhancer factor 1 (LEF1) and signal transducer and activator of transcription 3 (STAT3) using RT-PCR. GAPDH was used as a reference gene. Mean percentage surface expression of CD38 and CTLA-4 was 21.96% and 45.25% respectively. Mean ∆CT gene expression levels of CCND1, CTLA-4, LEF1 and STAT3 were 12.03, 5.57 , 5.99 and 8.98 respectively. RBP4 and STRA6 gene expression levels were undetectable in all 20 patients. Gene expression of LEF1 showed significant correlations with CTLA-4 (rs=0.572, p=0.008), CCND1 (rs=0.61, p=0.004) and STAT3 (rs=0.587, p=0.006). There was also a significant correlation between gene expression of CCND1 and of STAT3 (r =0.499, p=0.025). No significant correlations were found between percentage surface expression of CTLA-4 and gene expression levels of either CTLA-4 or of LEF1. A weak negative correlation between percentage surface expression of CTLA-4 and of CD38 was not statistically significant. Comparing untreated and previously treated patients, there was no significant difference in gene expression levels of CTLA-4 and of LEF1 or in surface expression of CTLA-4. The failure to detect RBP4 and STRA6 gene expression in unstimulated peripheral blood CLL cells is evidence against an autocrine retinoid effect in CLL, although upregulation of STRA6 gene expression following stimulation by retinoids might be anticipated. The Wnt signalling pathway has been shown to be active in CLL, including aggressive disease subtypes, highlighting the potential benefits in targeting this pathway. Intriguingly, CTLA-4 expression, although found to be the most highly induced gene following treatment with recombinant Wnt-3a in melanoma cell lines, is associated with a favourable outcome in CLL, possibly by inhibiting cell proliferation and survival. In contrast, expression of LEF1, which is a direct target of the Wnt signalling pathway, is associated with disease progression in CLL. Our finding that CTLA-4 and LEF1 gene expression levels are strongly correlated suggests that further investigation of the relationship between CTLA-4 and the Wnt/β-Catenin pathway in CLL is required and that targeting of the Wnt/β-catenin pathway may have unwanted consequences on CTLA-4 expression and function. Disclosures Quinn: Celgene: Honoraria; Janssen Cilag: Honoraria.
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Niederreither, K., J. Vermot, B. Schuhbaur, P. Chambon, and P. Dolle. "Retinoic acid synthesis and hindbrain patterning in the mouse embryo." Development 127, no. 1 (January 1, 2000): 75–85. http://dx.doi.org/10.1242/dev.127.1.75.
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Targeted disruption of the murine retinaldehyde dehydrogenase 2 (Raldh2) gene precludes embryonic retinoic acid (RA) synthesis, leading to midgestational lethality (Niederreither, K., Subbarayan, V., Dolle, P. and Chambon, P. (1999). Nature Genet. 21, 444–448). We describe here the effects of this RA deficiency on the development of the hindbrain and associated neural crest. Morphological segmentation is impaired throughout the hindbrain of Raldh2−/− embryos, but its caudal portion becomes preferentially reduced in size during development. Specification of the midbrain region and of the rostralmost rhombomeres is apparently normal in the absence of RA synthesis. In contrast, marked alterations are seen throughout the caudal hindbrain of mutant embryos. Instead of being expressed in two alternate rhombomeres (r3 and r5), Krox20 is expressed in a single broad domain, correlating with an abnormal expansion of the r2-r3 marker Meis2. Instead of forming a defined r4, Hoxb1- and Wnt8A-expressing cells are scattered throughout the caudal hindbrain, whereas r5/r8 markers such as kreisler or group 3/4 Hox genes are undetectable or markedly downregulated. Lack of alternate Eph receptor gene expression could explain the failure to establish rhombomere boundaries. Increased apoptosis and altered migratory pathways of the posterior rhombencephalic neural crest cells are associated with impaired branchial arch morphogenesis in mutant embryos. We conclude that RA produced by the embryo is required to generate posterior cell fates in the developing mouse hindbrain, its absence leading to an abnormal r3 (and, to a lesser extent, r4) identity of the caudal hindbrain cells.
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Anchan, Raymond M., Daniel P. Drake, Charles F. Haines, Elizabeth A. Gerwe, and Anthony-Samuel LaMantia. "Disruption of local retinoid-mediated gene expression accompanies abnormal development in the mammalian olfactory pathway." Journal of Comparative Neurology 379, no. 2 (March 10, 1997): 171–84. http://dx.doi.org/10.1002/(sici)1096-9861(19970310)379:2<171::aid-cne1>3.0.co;2-0.
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Kiefer, Florian W., Gabriela Orasanu, Shriram Nallamshetty, Jonathan D. Brown, Hong Wang, Philip Luger, Nathan R. Qi, Charles F. Burant, Gregg Duester, and Jorge Plutzky. "Retinaldehyde Dehydrogenase 1 Coordinates Hepatic Gluconeogenesis and Lipid Metabolism." Endocrinology 153, no. 7 (May 3, 2012): 3089–99. http://dx.doi.org/10.1210/en.2011-2104.
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Recent data link vitamin A and its retinoid metabolites to the regulation of adipogenesis, insulin sensitivity, and glucose homeostasis. Retinoid metabolism is tightly controlled by an enzymatic network in which retinaldehyde dehydrogenases (Aldh1–3) are the rate-limiting enzymes that convert retinaldehyde to retinoic acid. Aldh1a1-deficient mice are protected from diet-induced obesity and hence diabetes. Here we investigated whether Aldh1a1 and the retinoid axis regulate hepatic glucose and lipid metabolism independent of adiposity. The impact of Aldh1a1 and the retinoid pathway on glucose homeostasis and lipid metabolism was analyzed in hepatocytes in vitro and in chow-fed, weight-matched Aldh1a1-deficient vs. wild-type (WT) mice in vivo. Aldh1a1-deficient mice displayed significantly decreased fasting glucose concentrations compared with WT controls as a result of attenuated hepatic glucose production. Expression of key gluconeogenic enzymes as well as the activity of Forkhead box O1 was decreased in Aldh1a1-deficient vs. WT livers. In vitro, retinoid or cAMP agonist stimulation markedly induced gluconeogenesis in WT but not Aldh1a1-deficient primary hepatocytes. Aldh1a1 deficiency increased AMP-activated protein kinase α activity, decreased expression of lipogenic targets of AMP-activated protein kinase α and significantly attenuated hepatic triacylglycerol synthesis. In metabolic cage studies, lean Aldh1a1-deficient mice manifested enhanced oxygen consumption and reduced respiratory quotient vs. WT controls, consistent with increased expression of fatty acid oxidation markers in skeletal muscle. Taken together, this work establishes a role for retinoid metabolism in glucose homeostasis in vivo and for Aldh1a1 as a novel determinant of gluconeogenesis and lipid metabolism independent of adiposity.
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van der Wees, J., J. G. Schilthuis, C. H. Koster, H. Diesveld-Schipper, G. E. Folkers, P. T. van der Saag, M. I. Dawson, K. Shudo, B. van der Burg, and A. J. Durston. "Inhibition of retinoic acid receptor-mediated signalling alters positional identity in the developing hindbrain." Development 125, no. 3 (February 1, 1998): 545–56. http://dx.doi.org/10.1242/dev.125.3.545.
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Retinoids regulate gene expression via nuclear retinoic acid receptors, the RARs and RXRs. To investigate the functions of retinoid receptors during early neural development, we expressed a dominant negative RARbeta in early Xenopus embryos. We obtained evidence that dominant negative RARbeta specifically inhibits RAR/RXR heterodimer-mediated, but not RXR homodimer-mediated, transactivation. Both all-trans- and 9-cis-RA-induced teratogenesis were, however, efficiently opposed by ectopic expression of dominant negative RARbeta, indicating that only RAR/RXR transactivation is required for retinoid teratogenesis by each of these ligands. Experiments with two RXR-selective ligands confirmed that activation of RXR homodimers does not cause retinoid teratogenesis. Dominant negative RARbeta thus specifically interferes with the retinoid signalling pathway that is responsible for retinoid teratogenesis. Dominant negative RARbeta-expressing embryos had a specific developmental phenotype leading to disorganization of the hindbrain. Mauthner cell multiplications in the posterior hindbrain, and (both anteriorly and posteriorly) expanded Krox-20 expression domains indicated (partial) transformation of a large part of the hindbrain into (at least partial) rhombomere 3, 4 and/or 5 identity. In contrast, the fore- and midbrain and spinal cord appeared to be less affected. These data indicate that RARs play a role in patterning the hindbrain.
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Park, Dorothy J., Peter T. Vuong, Sven de Vos, Dan Douer, and H. Phillip Koeffler. "Comparative analysis of genes regulated by PML/RARα and PLZF/RARα in response to retinoic acid using oligonucleotide arrays." Blood 102, no. 10 (November 15, 2003): 3727–36. http://dx.doi.org/10.1182/blood-2003-02-0412.
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Abstract Acute promyelocytic leukemia (APL) is associated with chromosomal translocations involving retinoic acid receptor α (RARα) and its fusion partners including promyelocytic leukemia (PML) and promyelocytic leukemia zinc finger (PLZF). Using oligonucleotide arrays, we examined changes in global gene expression mediated by the ectopic expression of either PML/RARα (retinoid-sensitive) or PLZF/RARα (retinoid-resistant) in U937 cells. Of more than 5000 genes analyzed, 16 genes were commonly up-regulated, and 57 genes were down-regulated by both fusion proteins suggesting their role in the APL phenotype. In our APL model, for example, TNFAIP2, TNFR2, ELF4, RARγ, and HoxA1 were down-regulated by both fusion proteins in the absence of retinoic acid (RA). RA strongly up-regulated these genes in PML/RARα, but not in PLZF/RARα expressing U937 cells. Expression studies in NB4, retinoid-resistant NB4-R2, normal human CD34+ cells, and APL patient samples strongly suggest their role in the regulation of granulocytic differentiation. Furthermore, combined treatment with tumor necrosis factor α (TNFα) and RA synergistically enhanced granulocytic differentiation in NB4 cells but not in NB4-R2 cells. Our data indicate that APL pathogenesis and retinoid-induced granulocytic differentiation of APL cells involve genes in the cell death pathway, and that cooperation between the RA and TNFα signaling pathways exists. Targeting both the retinoid-dependent differentiation and the cell death pathways may improve leukemic therapy, especially in retinoid-resistant acute myeloid leukemia. (Blood. 2003;102:3727-3736)
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Hoffman, Lisa M., Kamal Garcha, Konstantina Karamboulas, Matthew F. Cowan, Linsay M. Drysdale, William A. Horton, and T. Michael Underhill. "BMP action in skeletogenesis involves attenuation of retinoid signaling." Journal of Cell Biology 174, no. 1 (July 3, 2006): 101–13. http://dx.doi.org/10.1083/jcb.200604150.
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The bone morphogenetic protein (BMP) and growth and differentiation factor (GDF) signaling pathways have well-established and essential roles within the developing skeleton in coordinating the formation of cartilaginous anlagen. However, the identification of bona fide targets that underlie the action of these signaling molecules in chondrogenesis has remained elusive. We have identified the gene for the retinoic acid (RA) synthesis enzyme Aldh1a2 as a principal target of BMP signaling; prochondrogenic BMPs or GDFs lead to attenuation of Aldh1a2 expression and, consequently, to reduced activation of the retinoid signaling pathway. Consistent with this, antagonism of retinoid signaling phenocopies BMP4 action, whereas RA inhibits the chondrogenic stimulatory activity of BMP4. BMP4 also down-regulates Aldh1a2 expression in organ culture and, consistent with this, Aldh1a2 is actively excluded from the developing cartilage anlagens. Collectively, these findings provide novel insights into BMP action and demonstrate that BMP signaling governs the fate of prechondrogenic mesenchyme, at least in part, through regulation of retinoid signaling.
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Shao, Wenlin, Laura Benedetti, William W. Lamph, Clara Nervi, and Wilson H. Miller. "A Retinoid-Resistant Acute Promyelocytic Leukemia Subclone Expresses a Dominant Negative PML-RARα Mutation." Blood 89, no. 12 (June 15, 1997): 4282–89. http://dx.doi.org/10.1182/blood.v89.12.4282.
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Abstract The unique t(15; 17) of acute promyelocytic leukemia (APL) fuses the PML gene with the retinoic acid receptor α (RARα) gene. Although retinoic acid (RA) inhibits cell growth and induces differentiation in human APL cells, resistance to RA develops both in vitro and in patients. We have developed RA-resistant subclones of the human APL cell line, NB4, whose nuclear extracts display altered RA binding. In the RA-resistant subclone, R4, we find an absence of ligand binding of PML-RARα associated with a point mutation changing a leucine to proline in the ligand-binding domain of the fusion PML-RARα protein. In contrast to mutations in RARα found in retinoid-resistant HL60 cells, in this NB4 subclone, the coexpressed RARα remains wild-type. In vitro expression of a cloned PML-RARα with the observed mutation in R4 confirms that this amino acid change causes the loss of ligand binding, but the mutant PML-RARα protein retains the ability to heterodimerize with RXRα and thus to bind to retinoid response elements (RAREs). This leads to a dominant negative block of transcription from RAREs that is dose-dependent and not relieved by RA. An unrearranged RARα engineered with this mutation also lost ligand binding and inhibited transcription in a dominant negative manner. We then found that the mutant PML-RARα selectively alters regulation of gene expression in the R4 cell line. R4 cells have lost retinoid-regulation of RXRα and RARβ and the RA-induced loss of PML-RARα protein seen in NB4 cells, but retain retinoid-induction of CD18 and CD38. Thus, the R4 cell line provides data supporting the presence of an RARα-mediated pathway that is independent from gene expression induced or repressed by PML-RARα. The high level of retinoid resistance in vitro and in vivo of cells from some relapsed APL patients suggests similar molecular changes may occur clinically.
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Quinn, Jeanette M., Mats Eriksson, Jeffrey L. Moseley, and Sabeeha Merchant. "Oxygen Deficiency Responsive Gene Expression inChlamydomonas reinhardtii through a Copper-Sensing Signal Transduction Pathway." Plant Physiology 128, no. 2 (February 1, 2002): 463–71. http://dx.doi.org/10.1104/pp.010694.
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Everaert, Bert R., Steven J. Van Laere, Robrecht Lembrechts, Vicky Y. Hoymans, Jean-Pierre Timmermans, and Christiaan J. Vrints. "Identification of Macrophage Genotype and Key Biological Pathways in Circulating Angiogenic Cell Transcriptome." Stem Cells International 2019 (May 2, 2019): 1–12. http://dx.doi.org/10.1155/2019/9545261.
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Background. Circulating angiogenic cells (CAC) have been identified as important regulators of vascular biology. However, there is still considerable debate about the genotype and function of CAC. Methods and Results. Data from publicly available gene expression data sets were used to analyse the transcriptome of in vitro cultured CAC (CACiv). Genes and pathways of interest were further evaluated using qPCR comparing CACiv versus CD14+ monocytic cells. The CACiv transcriptome strongly related to tissue macrophages, and more specifically to regulatory M2c macrophages. The cytokine expression profile of CACiv was predominantly immune modulatory and resembled the cytokine expression of tumor-associated macrophages (TAM). Pathway analysis revealed previously unrecognized biological processes in CACiv, such as riboflavin metabolism and liver X receptor (LXR)/retinoid X receptor (RXR) and farnesoid X receptor (FXR)/retinoid X receptor (RXR) pathways. Analysis of endothelial-specific genes did not show evidence for endothelial transdifferentiation. Conclusions. CACiv are genotypically similar to regulatory M2c macrophages and lack signs of endothelial differentiation.
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Vernet, Nadège, Christine Dennefeld, Muriel Klopfenstein, Alberto Ruiz, Dean Bok, Norbert B. Ghyselinck, and Manuel Mark. "Retinoid X receptor beta (RXRB) expression in Sertoli cells controls cholesterol homeostasis and spermiation." REPRODUCTION 136, no. 5 (November 2008): 619–26. http://dx.doi.org/10.1530/rep-08-0235.
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Somatic, targeted inactivation of the retinoid X receptor beta gene (Rxrb) in Sertoli cells (SC; yielding RxrbSer−/− mutants) leads to failure of spermatid release, accumulation of cholesterol esters and, subsequently, testis degeneration. These abnormalities are identical, in their nature and kinetics, to those observed upon inactivating Rxrb in the whole organism, thereby demonstrating that all reproductive functions of RXRB are carried out in SC. The RxrbSer−/− testis degeneration is a consequence of a cholesterol ester cell overload occurring in SC in response to reduced ABCA1- and SCARB1-mediated cholesterol efflux. The failure of spermiation was also reported in mice lacking the retinoic acid (RA) receptor-α (RARA) in SC (RaraSer−/− mutants) and represents, in addition, a feature of vitamin A deficiency that can be readily induced in mice lacking the lecithin:retinol acyltransferase (Lrat−/− mutants). Altogether, these findings support the conclusion that RXRB heterodimerized with a RA-liganded RARA transduces signals required in SC for spermatid release.
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Lopez, Mary Frances, Lingyun Zheng, Ji Miao, Reddy Gali, Grzegorz Gorski, and Joel N. Hirschhorn. "Disruption of the Igf2 gene alters hepatic lipid homeostasis and gene expression in the newborn mouse." American Journal of Physiology-Endocrinology and Metabolism 315, no. 5 (November 1, 2018): E735—E744. http://dx.doi.org/10.1152/ajpendo.00048.2018.
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Newborns with intrauterine growth-restriction are at increased risk of mortality and life-long comorbidities. Insulin-like growth factor-II (IGF2) deficiency in humans, as well as in mice, leads to intrauterine growth restriction and decreased neonatal glycogen stores. The present study aims to further characterize the metabolic and transcriptional consequences of Igf2 deficiency in the newborn. We found that, despite being born significantly smaller than their wild-type ( Igf2+/+) littermates, brain size was preserved in Igf2 knockout ( Igf2−/−), consistent with nutritional deficiency. Histological and triglyceride analyses of newborn livers revealed that Igf2−/− mice are born with hepatic steatosis. Gene expression analysis in Igf2−/− newborn livers showed an alteration of genes known to be dysregulated in chronic caloric restriction, including the most upregulated gene, serine dehydratase. Multiple genes connected with lipid metabolism and/or hepatic steatosis were also upregulated. Ingenuity Pathway Analysis confirmed that the biological functions most altered in livers of Igf2−/− newborns are related to lipid metabolism, with the top upstream regulator predicted to be the peroxisome proliferator-activated receptor alpha, a master regulator of hepatic lipid and carbohydrate homeostasis. Together, our data indicate that Igf2 deficiency leads to a newborn phenotype strongly reminiscent of nutritional deficiency, including growth retardation, increased brain/body weight ratio, hepatic steatosis, and characteristic changes in hepatic gene expression. We propose that in addition to its growth factor proliferating functions, Igf2 may also regulate growth by altering the expression of genes that control nutrient metabolism in the newborn.
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Houle, Martin, Panagiotis Prinos, Angelo Iulianella, Nathalie Bouchard, and David Lohnes. "Retinoic Acid Regulation of Cdx1: an Indirect Mechanism for Retinoids and Vertebral Specification." Molecular and Cellular Biology 20, no. 17 (September 1, 2000): 6579–86. http://dx.doi.org/10.1128/mcb.20.17.6579-6586.2000.
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ABSTRACT Retinoic acid (RA) is required for diverse developmental programs, including vertebral specification. Both RA receptor disruption and excess RA result in homeotic transformations of the axial skeleton. These effects are believed to occur through altered expression ofHox genes, several of which have been demonstrated to be direct RA targets. Members of the cdx (caudal) homeobox gene family are also implicated in regulating Hoxexpression. Disruption of cdx1 results in vertebral homeotic transformations and alteration of Hox expression boundaries; similar homeosis is also observed in cdx2heterozygotes. In Xenopus, gain or loss of Cdx function affects vertebral morphogenesis through a mechanism that also correlates with altered Hox expression. Taken together with the finding of putative Cdx binding motifs in several Hoxpromoters, these data strongly support a role for Cdx members in direct regulation of expression of at least some Hox genes. Most retinoid-responsive Hox genes have not been demonstrated to be direct RA targets, suggesting that intermediaries are involved. Based on these findings, we hypothesized that one or morecdx members may transduce the effects of RA onHox transcription. Consistent with this, we present evidence that cdx1 is a direct RA target gene, suggesting an additional pathway for retinoid-dependent vertebral specification.
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Quere, Ronan, Aurelie Baudet, Bruno Cassinat, Gerald Bertrand, Jacques Marti, Laurent Manchon, David Piquemal, Christine Chomienne, and Therese Commes. "Pharmacogenomic analysis of acute promyelocytic leukemia cells highlights CYP26 cytochrome metabolism in differential all-trans retinoic acid sensitivity." Blood 109, no. 10 (January 11, 2007): 4450–60. http://dx.doi.org/10.1182/blood-2006-10-051086.
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AbstractDisease relapse sometimes occurs after acute promyelocytic leukemia (APL) therapy with all-trans retinoic acid (ATRA). Among the diagnostic parameters predicting relapse, heterogeneity in the in vitro differentiation rate of blasts is an independent factor. To identify biologic networks involved in resistance, we conducted pharmacogenomic studies in APL blasts displaying distinct ATRA sensitivities. Although the expression profiles of genes invested in differentiation were similarly modulated in low- and high-sensitive blasts, low-sensitive cells showed higher levels of transcription of ATRA-target genes, transcriptional regulators, chromatin remodelers, and transcription factors. In opposition, only high-sensitive blasts expressed the CYP26A1 gene, encoding the p450 cytochrome which is known to be involved in retinoic acid catabolism. In NB4 cells, ATRA treatment activates a novel signaling pathway, whereby interleukin-8 stimulates the expression of the homeobox transcription factor HOXA10v2, an effective enhancer of CYP26A1 transcription. These data were corroborated in primary APL cells, as maturation levels correlated with CYP26A1 expression. Treatment with a retinoic acid metabolism blocking agent (RAMBA) results in high-nucleoplasmic concentrations of retinoid and growth of NB4-resistant subclones. Hence, for APL blasts associated with poor prognosis, the low CYP26A1 expression may explain high risk of resistance installation, by increased retinoid pressure. Pharmacogenomic profiles of genes involved in retinoid acid metabolism may help to optimize anticancer therapies, including retinoids.
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MOREL, Yannick, and Robert BAROUKI. "Repression of gene expression by oxidative stress." Biochemical Journal 342, no. 3 (September 5, 1999): 481–96. http://dx.doi.org/10.1042/bj3420481.
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Gene expression is modulated by both physiological signals (hormones, cytokines, etc.) and environmental stimuli (physical parameters, xenobiotics, etc.). Oxidative stress appears to be a key pleiotropic modulator which may be involved in either pathway. Indeed, reactive oxygen species (ROS) have been described as second messengers for several growth factors and cytokines, but have also been shown to rise following cellular insults such as xenobiotic metabolism or enzymic deficiency. Extensive studies on the induction of stress-response genes by oxidative stress have been reported. In contrast, owing to the historical focus on gene induction, less attention has been paid to gene repression by ROS. However, a growing number of studies have shown that moderate (i.e. non-cytotoxic) oxidative stress specifically down-regulates the expression of various genes. In this review, we describe the alteration of several physiological functions resulting from oxidative-stress-mediated inhibition of gene transcription. We will then focus on the repressive oxidative modulation of various transcription factors elicited by ROS.
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Kato, S., H. Mano, T. Kumazawa, Y. Yoshizawa, R. Kojima, and S. Masushige. "Effect of retinoid status on α, β and γ retinoic acid receptor mRNA levels in various rat tissues." Biochemical Journal 286, no. 3 (September 15, 1992): 755–60. http://dx.doi.org/10.1042/bj2860755.
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We have investigated the effects of retinoids, vitamin D and thyroid hormone on the levels of retinoic acid receptor (RAR)alpha, RAR beta and RAR gamma mRNAs in intact animals. Although vitamin A deficiency caused no significant changes in the levels of RAR alpha and RAR gamma mRNAs, the level of RAR beta transcripts was greatly decreased in various tissues of vitamin A-deficient rats, but was restored rapidly to a normal level after administration of retinoic acid. Retinol also restored the RAR beta mRNA level, but the magnitude and kinetics of the induction differed from those by retinoic acid. The use of specific inhibitors demonstrated that this autoregulation of RAR beta gene expression in vivo occurred at the transcriptional level. In addition, from these results it was postulated that the maintenance of the normal RAR beta mRNA levels seemed to require a threshold serum retinol concentration (about 25 micrograms/dl). Moreover, we found that administration of retinol and retinoic acid to normal rats caused the overexpression of RAR beta transcripts (2-15-fold) when compared with the control levels of RAR beta mRNA, although the levels of RAR alpha and RAR gamma mRNAs were not affected. Vitamin D and thyroid hormone did not modulate the levels of RAR transcripts. These findings clearly indicate the specific ligand regulation of RAR beta gene expression in intact animals. The altered levels of RAR beta according to retinoid status may affect retinoid-inducible gene expression.
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Chen, Yu, Yanling Wu, Haiqiang Yao, Hui Luo, Bing Lin, Xiuping Zhang, Xue Liang, et al. "miRNA Expression Profile of Saliva in Subjects of Yang Deficiency Constitution and Yin Deficiency Constitution." Cellular Physiology and Biochemistry 49, no. 5 (2018): 2088–98. http://dx.doi.org/10.1159/000493769.
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Background/Aims: Based on the theory of constitution in Traditional Chinese Medicine (TCM), the Chinese Han population has been classified into nine constitutions. Of these, Yang deficiency constitution mainly exhibit cold intolerance while Yin deficiency constitution mainly exhibit heat intolerance. Some studies have been carried out to explore the modern genetic and biological basis of such constitution classification, but more remains to be done. MicroRNA (miRNA) serves as post-transcriptional regulators of gene expression and may play a role in the classification process. Here, we examined miRNA expression profile of saliva to further improve the comprehensiveness of constitution classification. Methods: Saliva was collected from Chinese Han individuals with Yang deficiency, Yin deficiency and Balanced constitutions (n=5 each), and miRNA expression profile was determined using the Human miRNA OneArray®v7. Based on 1.5 Fold change, means log2|Ratio|≥0.585 and P-value< 0.05, differentially expressed miRNA was screened. Target genes were predicted using DIANA-TarBasev7.0 and analysis of KEGG pathway was carried out using DIANA-mirPathv.3. Results: We found that 81 and 98 differentially expressed miRNAs were screened in Yang deficiency and Yin deficiency constitution, respectively. Among them, 16 miRNAs were identical and the others were unique. In addition, the target genes that are regulated by the unique miRNAs were significantly enriched in 27 and 20 signaling pathways in Yang deficiency and Yin deficiency constitution, respectively. Thyroid hormone signaling pathway is present in both constitutions. These unique miRNAs that regulated target genes of thyroid hormone signaling pathway may be associated with cold intolerance or heat intolerance. Conclusion: The results of our study show that Yang deficiency and Yin deficiency constitutions exhibit systematic differences in miRNA expression profile. Moreover, the distinct characteristics of TCM constitution may be explained, in part, by differentially expressed miRNAs.
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Kobayashi, Mime, Ruth T. Yu, Kunio Yasuda, and Kazuhiko Umesono. "Cell-Type-Specific Regulation of the Retinoic Acid Receptor Mediated by the Orphan Nuclear Receptor TLX." Molecular and Cellular Biology 20, no. 23 (December 1, 2000): 8731–39. http://dx.doi.org/10.1128/mcb.20.23.8731-8739.2000.
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ABSTRACT Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor β (RARβ). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARβ2 promoter. The region surrounding the transcription start site of the avian RARβ2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARβ2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARβ gene in the eye.
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Ding, Yan, Lanlan Shan, Wenqing Nai, Xiaojun Lin, Ling Zhou, Xiaoying Dong, Hongyuan Wu, et al. "DEPTOR Deficiency-Mediated mTORc1 Hyperactivation in Vascular Endothelial Cells Promotes Angiogenesis." Cellular Physiology and Biochemistry 46, no. 2 (2018): 520–31. http://dx.doi.org/10.1159/000488619.
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Background/Aims: The mechanistic target of rapamycin (mTOR) signaling pathway is essential for angiogenesis and embryonic development. DEP domain-containing mTOR-interacting protein (DEPTOR) is an mTOR binding protein that functions to inhibit the mTOR pathway In vitro experiments suggest that DEPTOR is crucial for vascular endothelial cell (EC) activation and angiogenic responses. However, knowledge of the effects of DEPTOR on angiogenesis in vivo is limited. This study aimed to determine the role of DEPTOR in tissue angiogenesis and to elucidate the molecular mechanisms. Methods: Cre/loxP conditional gene knockout strategy was used to delete the Deptor gene in mouse vascular ECs. The expression or distribution of cluster of differentiation 31 (CD31), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1 alpha (HIF-1α) were detected by immunohistochemical staining or western blot. Tube formation assay was used to measure angiogenesis in vitro. Results: Deptor knockdown led to increased expression of CD31, VEGF and HIF-1α in heart, liver, kidney and aorta. After treatment with rapamycin, their expression was significantly down regulated. In vitro, human umbilical vein endothelial cells (HUVECs) were transfected with DEPTOR-specific small interfering RNA (siRNA), which resulted in a significant increase in endothelial tube formation and migration rates. In contrast, DEPTOR overexpression markedly reduced the expression of CD31, VEGF and HIF-1α. Conclusions: Our findings demonstrated that deletion of the Deptor gene in vascular ECs resulted in upregulated expression of CD31 and HIF-1α, and further stimulated the expression of VEGF which promoted angiogenesis, indicating that disruption of normal angiogenic pathways may occur through hyperactivation of the mTORC1/HIF-1α/VEGF signaling pathway.
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Ginnard, Olivia Z. B., and Stephanie Sisley. "Expression of Vitamin D Receptor Pathway Genes in Subcutaneous Adipose Tissue of Obese Individuals." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A658. http://dx.doi.org/10.1210/jendso/bvab048.1342.
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Abstract Introduction: Vitamin D deficiency is a substantial comorbidity in 50% of pediatric patients and is linked with poorer health outcomes in children. Vitamin D levels are also shown to be inversely related to BMI. Therefore, there are many more children with low vitamin D levels due to the increasing prevalence of pediatric obesity. Pediatric patients with obesity and vitamin D deficiency also have a uniquely increased risk of metabolic syndrome, as compared to their lean peers. Measured levels of vitamin D correlate with other physiological markers of vitamin D effects in lean individuals but not obese individuals. It is possible that vitamin D levels reflect a storage form of vitamin D rather than a true reflection of vitamin D action in the body in this particular population. The aim of this study was to provide foundational knowledge to understand if expression of vitamin D receptor (VDR)-target genes may be used as a reference standard for vitamin D status in the body. Methods: We performed a secondary analysis of samples obtained from 33 obese adolescents that were consented under a past IRB-approved protocol. They were between the ages of 13 to 18 years that underwent bariatric surgery between 2004 and 2019. Data comprised of age, gender, race/ethnicity, and BMI. Samples collected included blood and subcutaneous adipose tissue. The tissue was analyzed via Real Time-PCR to obtain quantitative levels of VDR-target gene expression, which included PPARg, TLR4, THBD, CYP24A1, and VDR. Gene expression levels were normalized to the average of two housekeeping genes, GAPDH and RPLPO. Blood samples provided vitamin D levels (serum 25(OH)D). Results: VDR-target gene expression was significantly correlated between THBD, VDR, and TLR4 (p <0.05), and PPARg with THBD and TLR4 (p <0.05). There was no correlation observed between CYP24A1 gene expression and the other genes that were evaluated (p >0.05). PPARg, THBD, TLR4, CYP24A1, and VDR gene expression levels did not correlate with circulating serum 25(OH)D levels (p >0.05). Conclusion: These preliminary findings suggest that VDR-target gene expression correlates with each other but not with circulating serum 25(OH)D levels. This discrepancy supports that 25(OH)D levels do not indicate levels of vitamin D action and may not be an appropriate indicator of vitamin D deficiency in the obese population. Also, the observed CYP24A1 gene expression was limited in subcutaneous adipose tissue yet expression was seen in multiple other VDR-target genes. This emphasizes the tissue-specific nature of gene regulation of vitamin D. Further work should investigate VDR-target gene expression levels across multiple tissues of obese individuals to determine if markers of vitamin D action in one tissue are reflective of action across the body. This study may provide the first step in determining a new and more accurate biomarker for vitamin D deficiency and treatment in obesity.
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Pisanti, Simona, Marianna Citro, Mario Abate, Mariella Caputo, and Rosanna Martinelli. "Gene Expression Analysis of Mevalonate Kinase Deficiency Affected Children Identifies Molecular Signatures Related to Hematopoiesis." International Journal of Environmental Research and Public Health 18, no. 3 (January 28, 2021): 1170. http://dx.doi.org/10.3390/ijerph18031170.
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Mevalonate kinase deficiency (MKD) is a rare autoinflammatory genetic disorder characterized by recurrent fever attacks and systemic inflammation with potentially severe complications. Although it is recognized that the lack of protein prenylation consequent to mevalonate pathway blockade drives IL1β hypersecretion, and hence autoinflammation, MKD pathogenesis and the molecular mechanisms underlaying most of its clinical manifestations are still largely unknown. In this study, we performed a comprehensive bioinformatic analysis of a microarray dataset of MKD patients, using gene ontology and Ingenuity Pathway Analysis (IPA) tools, in order to identify the most significant differentially expressed genes and infer their predicted relationships into biological processes, pathways, and networks. We found that hematopoiesis linked biological functions and pathways are predominant in the gene ontology of differentially expressed genes in MKD, in line with the observed clinical feature of anemia. We also provided novel information about the molecular mechanisms at the basis of the hematological abnormalities observed, that are linked to the chronic inflammation and to defective prenylation. Considering the broad and unspecific spectrum of MKD clinical manifestations and the difficulty in its diagnosis, a better understanding of MKD molecular bases could be translated to the clinical level to facilitate diagnosis, and improve management and therapy.
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Khanna-Gupta, Arati, Stephanie Halene, Hong Sun, Richard Dahl, Laurence A. Boxer, and Nancy Berliner. "Identification of Common Molecular Pathways in Granulopoiesis Associated with C/EBP Epsilon and Gfi-1-Deficient Neutrophil Specific Granule Deficiency (SGD)." Blood 108, no. 11 (November 16, 2006): 1196. http://dx.doi.org/10.1182/blood.v108.11.1196.1196.
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Abstract Neutrophil specific granule deficiency (SGD) is a rare congenital disorder marked by recurrent bacterial infections of the skin and respiratory system. Neutrophils from SGD patients lack secondary and tertiary granules and their content proteins and exhibit defects in chemotaxis and bactericidal activity. A mouse model deficient for the transcription factor CCAAT/enhancer binding protein epsilon (C/EBPε) manifests a similar phenotype to SGD patients, and functional mutations in the C/EBPε gene have been identified in two patients with SGD. However, other patients with a similar disease phenotype do not have functional C/EBPε mutations, suggesting that other genetic abnormalities in myelopoiesis can lead to SGD. Studies in our laboratory on one such patient lacking a functional C/EBPε mutation demonstrated elevated protein levels of C/EBPε and significantly decreased levels of the transcription factor Gfi-1 (Growth factor independent-1) in peripheral blood neutrophils from this SGD patient. However, no mutation has been found thus far in the coding region of the Gfi-1 gene from the SGD patient. SGD can therefore be classified as C/EBPε negative or C/EBPε positive. We hypothesize that during granulopoiesis defects in a common molecular pathway occur in both C/EBPε- positive and -negative SGD resulting in the SGD phenotype. In order to gain insight into the molecular features of the two SGD phenotypes in the face of severe limitations on primary material from SGD patients, we have generated and characterized two cell line models. Using bone marrow from both C/EBPε−/− and Gfi-1+/− mice and their corresponding wildtype (WT) littermates, we generated EML (erythroid, myeloid, lymphoid) cell lines by transducing bone marrow with a retroviral vector expressing the dominant negative RARα and selecting for immortalized cells. Upon induction of the knock out and WT EML cell lines with all-trans retinoic acid (ATRA) to the neutrophil stage, we confirmed that both C/EBPε−/− and Gfi-1+/− cells share morphologic and functional abnormalities corresponding to their respective knockout mice, and hence to SGD. To further characterize the molecular defects in SGD, we have initiated microarray and proteomics analyses using RNA and protein prepared from both knockout cell lines. Using this approach, we may delineate defective pathways in both knock out cell types and correlate these observations to the specific SGD type. Our study should shed light on the relationship between Gfi-1 and C/EBPε during neutrophil development and should address the issue as to whether common or divergent molecular pathways are responsible for C/EBPε-negative and -positive SGD.
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Benedetti, L., F. Grignani, BM Scicchitano, AM Jetten, D. Diverio, F. Lo Coco, G. Avvisati, et al. "Retinoid-induced differentiation of acute promyelocytic leukemia involves PML-RARalpha-mediated increase of type II transglutaminase." Blood 87, no. 5 (March 1, 1996): 1939–50. http://dx.doi.org/10.1182/blood.v87.5.1939.1939.
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Abstract All-trans retinoic acid (t-RA) administration leads to complete remission in acute promyelocytic leukemia (APL) patients by inducing growth arrest and differentiation of the leukemic clone. In the present study, we show that t-RA treatment dramatically induced type II transglutaminase (type II TGase) expression in cells carrying the t(15;17) translocation and expressing the PML-RARalpha product such as the APL-derived NB4 cell line and fresh leukemic cells from APL patients. This induction correlated with t-RA-induced growth arrest, granulocytic differentiation, and upregulation of the leukocyte adherence receptor beta subunit (CD18) gene expression. The increase in type II TGase was not abolished by cycloheximide treatment, suggesting that synthesis of a protein intermediate was not required for the induction. t-RA did not significantly alter the rate of growth arrest and did not stimulate differentiation and type II TGase activity in NB4.306 cells, a t-RA-resistant subclone of the NB4 cell line, or in leukemic cells derived from two patients morphologically defined as APL but lacking the t(15;17). However, in NB4.306 cells, t-RA treatment was able to increase CD18 mRNA expression in a manner similar to NB4 cells. The molecular mechanisms involved in the induction of these genes were investigated. In NB4 cells, using novel receptor-selective ligands such as 9-cis-RA, TTNPB, AM580, and SR11217, we found that RAR- and RARalpha- selective retinoids were able to induce growth arrest, granulocytic differentiation, and type II TGase, whereas the RXR-selective retinoid SR11217 was inactive. Moreover, an RAR alpha-antagonist completely inhibited the expression of type II TGase and CD18 induced by these selective retinoids in NB4 cells. In NB4.306 cells, an RARalpha- dependent signaling pathway was found involved in the modulation of CD18 expression. In addition, expression of the PML-RARalpha gene in myeloid U937 precursor cells resulted in the ability of these cells to induce type II TGase in response to t-RA. On the basis of these results we hypothesize a specific involvement of a signaling pathway involving PML-RAR alpha for the induction of growth arrest, granulocytic differentiation, and type II TGase by retinoids in APL cells.
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Benedetti, L., F. Grignani, BM Scicchitano, AM Jetten, D. Diverio, F. Lo Coco, G. Avvisati, et al. "Retinoid-induced differentiation of acute promyelocytic leukemia involves PML-RARalpha-mediated increase of type II transglutaminase." Blood 87, no. 5 (March 1, 1996): 1939–50. http://dx.doi.org/10.1182/blood.v87.5.1939.bloodjournal8751939.
Full textAbstract:
All-trans retinoic acid (t-RA) administration leads to complete remission in acute promyelocytic leukemia (APL) patients by inducing growth arrest and differentiation of the leukemic clone. In the present study, we show that t-RA treatment dramatically induced type II transglutaminase (type II TGase) expression in cells carrying the t(15;17) translocation and expressing the PML-RARalpha product such as the APL-derived NB4 cell line and fresh leukemic cells from APL patients. This induction correlated with t-RA-induced growth arrest, granulocytic differentiation, and upregulation of the leukocyte adherence receptor beta subunit (CD18) gene expression. The increase in type II TGase was not abolished by cycloheximide treatment, suggesting that synthesis of a protein intermediate was not required for the induction. t-RA did not significantly alter the rate of growth arrest and did not stimulate differentiation and type II TGase activity in NB4.306 cells, a t-RA-resistant subclone of the NB4 cell line, or in leukemic cells derived from two patients morphologically defined as APL but lacking the t(15;17). However, in NB4.306 cells, t-RA treatment was able to increase CD18 mRNA expression in a manner similar to NB4 cells. The molecular mechanisms involved in the induction of these genes were investigated. In NB4 cells, using novel receptor-selective ligands such as 9-cis-RA, TTNPB, AM580, and SR11217, we found that RAR- and RARalpha- selective retinoids were able to induce growth arrest, granulocytic differentiation, and type II TGase, whereas the RXR-selective retinoid SR11217 was inactive. Moreover, an RAR alpha-antagonist completely inhibited the expression of type II TGase and CD18 induced by these selective retinoids in NB4 cells. In NB4.306 cells, an RARalpha- dependent signaling pathway was found involved in the modulation of CD18 expression. In addition, expression of the PML-RARalpha gene in myeloid U937 precursor cells resulted in the ability of these cells to induce type II TGase in response to t-RA. On the basis of these results we hypothesize a specific involvement of a signaling pathway involving PML-RAR alpha for the induction of growth arrest, granulocytic differentiation, and type II TGase by retinoids in APL cells.
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Lado-Abeal, J., A. Romero, I. Castro-Piedras, A. Rodriguez-Perez, and J. Alvarez-Escudero. "Thyroid hormone receptors are down-regulated in skeletal muscle of patients with non-thyroidal illness syndrome secondary to non-septic shock." European Journal of Endocrinology 163, no. 5 (November 2010): 765–73. http://dx.doi.org/10.1530/eje-10-0376.
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AimNon-thyroidal illness syndrome (NTIS) is related to changes in thyroid hormone (TH) physiology. Skeletal muscle (SM) plays a major role in metabolism, and TH regulates SM phenotype and metabolism. We aimed to characterize the SM of non-septic shock NTIS patients in terms of: i) expression of genes and proteins involved in TH metabolism and actions; and ii) NFKB's pathway activation, a responsible factor for some of the phenotypic changes in NTIS. We also investigated whether the patient's serum can induce in vitro the effects observed in vivo.MethodsSerum samples and SM biopsies from 14 patients with non-septic shock NTIS and 11 controls. Gene and protein expression and NFKB1 activation were analyzed by quantitative PCR and immunoblotting. Human SM cell (HSkMC) cultures to investigate the effects of patient's serum on TH action mediators.ResultsPatients with non-septic shock NTIS showed higher levels of pro-inflammatory cytokines than controls. Expression of TRβ (THRB), TRα1 (THRA), and retinoid X receptor γ (RXRG) was decreased in NTIS patients. RXRA gene expression was higher, but its protein was lower in NTIS than controls, suggesting the existence of a post-transcriptional mechanism that down-regulates protein levels. NFKB1 pathway activation was not different between NTIS and control patients. HSkMC incubated with patient's serum increased TH receptor and RXRG gene expression after 48 h.ConclusionsPatients with non-septic shock NTIS showed decreased expression of TH receptors and RXRs, which were not related to increased activation of the NFKB1 pathway. These findings could not be replicated in cultures of HSkMCs incubated in the patient's serum.
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Jiao, Xiaoyang, Rang Liu, Jiali Huang, Lichun Lu, Zibo Li, Liyan Xu, and Enmin Li. "Cellular Retinoic-Acid Binding Protein 2 in Solid Tumor." Current Protein & Peptide Science 21, no. 5 (June 2, 2020): 507–16. http://dx.doi.org/10.2174/1389203721666200203150721.
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The retinoic acid (RA) signaling pathway is crucial for many biological processes. The RA transporter, Cellular Retinoic-Acid Binding Protein 2 (CRABP2), is abnormally expressed in various tumor types. CRABP2 presents significant effects on tumorous behaviors and functions, including cell proliferation, apoptosis, invasion, migration, metastasis, and angiogenesis. The tumorigenesis mechanism of CRABP2, as both suppressor and promotor, is complicated, therefore, there remains the need for further investigation. Elucidating the regulating mechanisms in a specific stage of the tumor could facilitate CRABP2 to be a biomarker in cancer diagnosis and prognosis. Besides, clarifying the pathways of CRABP2 in cancer development will contribute to the gene-targeted therapy. In this review, we summarized the expression, distribution, and mechanism of CRABP2 in solid tumors. Illuminating the CRABP2 signaling pathway may benefit understanding the retinoid signaling pathway, providing a useful biomarker for future clinical trials.
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Fasseu, Magali, Peter D. Aplan, Martine Chopin, Nicolas Boissel, Jean-Christophe Bories, Jean Soulier, Harald von Boehmer, François Sigaux, and Armelle Regnault. "p16INK4A tumor suppressor gene expression and CD3ϵ deficiency but not pre-TCR deficiency inhibit TAL1-linked T-lineage leukemogenesis." Blood 110, no. 7 (October 1, 2007): 2610–19. http://dx.doi.org/10.1182/blood-2007-01-066209.
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Inactivation of the CDKN2 genes that encode the p16INK4A and p14ARF proteins occurs in the majority of human T-cell acute lymphoblastic leukemias (T-ALLs). Ectopic expression of TAL1 and LMO1 genes is linked to the development of T-ALL in humans. In TAL1xLMO1 mice, leukemia develops in 100% of mice at 5 months. To identify the molecular events crucial to leukemic transformation, we produced several mouse models. We report here that expression of P16INK4A in developing TAL1xLMO1 thymocytes blocks leukemogenesis in the majority of the mice, and the leukemias that eventually develop show P16INK4A loss of expression. Events related to the T-cell receptor β selection process are thought to be important for leukemic transformation. We show here that the absence of the pTα chain only slightly delays the appearance of TAL1xLMO1-induced T-ALL, which indicates a minor role of the pTα chain. We also show that the CD3ϵ-mediated signal transduction pathway is essential for this transformation process, since the TAL1xLMO1xCD3ϵ-deficient mice do not develop T-ALL for up to 1 year.
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Ross, R. S., S. Navankasattusas, R. P. Harvey, and K. R. Chien. "An HF-1a/HF-1b/MEF-2 combinatorial element confers cardiac ventricular specificity and established an anterior-posterior gradient of expression." Development 122, no. 6 (June 1, 1996): 1799–809. http://dx.doi.org/10.1242/dev.122.6.1799.
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The molecular determinants that direct gene expression to the ventricles of the heart are for the most part unknown. Additionally, little data is available on how the anterior/posterior axis of the heart tube is determined and whether the left and right atrial and ventricular chambers are assigned as part of this process. Utilizing myosin light chain-2 ventricular promoter/beta-galactosidase reporter transgenes, we have determined the minimal cis-acting sequences required for ventricular-specific gene expression. In multiple independent transgenic mouse lines, we found that both a 250 base pair myosin light chain-2 ventricular promoter fragment, as well as a dimerized 28 bp sub-element (HF-1) containing binding sites for HF1a and HF1b/MEF2 factors, directed ventricular-specific reporter expression from as early as the endogenous gene, at day 7.5-8.0 post coitum. While the endogenous gene is expressed uniformly throughout both ventricles, the transgenes were expressed in a right ventricular/conotruncal dominant fashion, suggesting that they contain only a subset of the elements which respond to positional information in the developing heart tube. Expression of the transgene was cell autonomous and its temporospatial characteristics not affected by mouse strain/methylation state of the genome. To determine whether ventricular-specific expression of the transgene was dependent upon regulatory genes required for correct ventricular differentiation, the 250 base pair transgene was bred into both retinoid X receptoralpha and Nkx2-5 null backgrounds. The transgene was expressed in both mutant backgrounds, despite the absence of endogenous myosin light chain-2 ventricular transcript in Nkx2-5 null embryos. Ventricular specification, as judged by transgene expression, appeared to occur normally in both mutants. Thus, the HF-1 element, directs chamber-specific transcription of a transgene reporter independently of retinoid X receptoralpha and Nkx2-5, and defines a minimal combinatorial pathway for ventricular chamber gene expression. The patterned expression of this transgene may provide a model system in which to investigate the cues that dictate anterior-posterior (right ventricle/left ventricle) gradients during mammalian heart development.
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Fan, Jinjiang, and Vassilios Papadopoulos. "Mitochondrial TSPO Deficiency Triggers Retrograde Signaling in MA-10 Mouse Tumor Leydig Cells." International Journal of Molecular Sciences 22, no. 1 (December 29, 2020): 252. http://dx.doi.org/10.3390/ijms22010252.
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The mitochondrial translocator protein (TSPO) has been shown to bind cholesterol with high affinity and is involved in mediating its availability for steroidogenesis. We recently reported that targeted Tspo gene deletion in MA-10 mouse tumor Leydig cells resulted in reduced cAMP-stimulated steroid formation and significant reduction in the mitochondrial membrane potential (ΔΨm) compared to control cells. We hypothesized that ΔΨm reduction in the absence of TSPO probably reflects the dysregulation and/or maintenance failure of some basic mitochondrial function(s). To explore the consequences of TSPO depletion via CRISPR-Cas9-mediated deletion (indel) mutation in MA-10 cells, we assessed the transcriptome changes in TSPO-mutant versus wild-type (Wt) cells using RNA-seq. Gene expression profiles were validated using real-time PCR. We report herein that there are significant changes in nuclear gene expression in Tspo mutant versus Wt cells. The identified transcriptome changes were mapped to several signaling pathways including the regulation of membrane potential, calcium signaling, extracellular matrix, and phagocytosis. This is a retrograde signaling pathway from the mitochondria to the nucleus and is probably the result of changes in expression of several transcription factors, including key members of the NF-κB pathway. In conclusion, TSPO regulates nuclear gene expression through intracellular signaling. This is the first evidence of a compensatory response to the loss of TSPO with transcriptome changes at the cellular level.
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Asson-Batres, Mary Ann, Sergey Ryzhov, Oleg Tikhomirov, Christine W. Duarte, Clare Bates Congdon, Craig R. Lessard, Samuel McFarland, et al. "Effects of vitamin A deficiency in the postnatal mouse heart: role of hepatic retinoid stores." American Journal of Physiology-Heart and Circulatory Physiology 310, no. 11 (June 1, 2016): H1773—H1789. http://dx.doi.org/10.1152/ajpheart.00887.2015.
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To determine whether hepatic depletion of vitamin A (VA) stores has an effect on the postnatal heart, studies were carried out with mice lacking liver retinyl ester stores fed either a VA-sufficient (LRVAS) or VA-deficient (LRVAD) diet (to deplete circulating retinol and extrahepatic stores of retinyl esters). There were no observable differences in the weights or gross morphology of hearts from LRVAS or LRVAD mice relative to sex-matched, age-matched, and genetically matched wild-type (WT) controls fed the VAS diet (WTVAS), but changes in the transcription of functionally relevant genes were consistent with a state of VAD in LRVAS and LRVAD ventricles. In silico analysis revealed that 58/67 differentially expressed transcripts identified in a microarray screen are products of genes that have DNA retinoic acid response elements. Flow cytometric analysis revealed a significant and cell-specific increase in the number of proliferating Sca-1 cardiac progenitor cells in LRVAS animals relative to WTVAS controls. Before myocardial infarction, LRVAS and WTVAS mice had similar cardiac systolic function and structure, as measured by echocardiography, but, unexpectedly, repeat echocardiography demonstrated that LRVAS mice had less adverse remodeling by 1 wk after myocardial infarction. Overall, the results demonstrate that the adult heart is responsive to retinoids, and, most notably, reducing hepatic VA stores (while maintaining circulating levels of VA) impacts ventricular gene expression profiles, progenitor cell numbers, and response to injury.
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Du, Yuna, Qianqian Dai, Huiqing Zhang, Qi Li, Kuangyu Song, Yingyuan Fu, Weiping Min, Zhenlong Liu, and Rong Li. "CD38 Deficiency Downregulates the Onset and Pathogenesis of Collagen-Induced Arthritis through the NF-κB Pathway." Journal of Immunology Research 2019 (March 5, 2019): 1–9. http://dx.doi.org/10.1155/2019/7026067.
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Aim. The RelB gene plays an important role in guiding the progression of arthritis. We have previously demonstrated that the expression of the RelB gene is decreased significantly in bone marrow DCs of CD38-/- mice. In this study, we demonstrate that the cluster of the differentiation (CD38) gene could be a potentially therapeutic target for autoimmune arthritis. Method. Collagen-induced arthritis (CIA) models were generated with both the wild-type (WT) C57BL/6 and CD38-/- mice. The expression of the RelB gene and maturation of bone marrow-derived dendritic cells (DCs) from the WT and CD38-/- mice were detected. Antigen-specific T cell responses, joint damage, and expression of proinflammatory cytokines were assessed. The effects of the Nuclear Factor Kappa B (NF-κB) transcription factor and its mechanisms were characterized. Results. We demonstrated that in CD38-/- mice, the expression of the RelB gene and major histocompatibility complex II (MHC II) was decreased, accompanied with the inhibited T cell reaction in a mixed lymphocyte reaction (MLR) in bone marrow-derived DCs. Compared to the serious degeneration of the cartilage and the enlarged gap of the cavum articular in WT CIA mice, joint pathological changes of the CD38-/- CIA mice revealed marked attenuation, while the joint structures were well preserved. The preserved effects were observed by the inhibition of proinflammatory cytokines and promotion of anti-inflammatory cytokines. Furthermore, decreased phosphorylation of NF-κB was also observed in CD38-/- CIA mice. Conclusion. We demonstrate that CD38 could regulate CIA through NF-κB and this regulatory molecule could be a novel target for the treatment of autoimmune inflammatory joint disease.
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Xue, J. C., E. J. Schwarz, A. Chawla, and M. A. Lazar. "Distinct stages in adipogenesis revealed by retinoid inhibition of differentiation after induction of PPARgamma." Molecular and Cellular Biology 16, no. 4 (April 1996): 1567–75. http://dx.doi.org/10.1128/mcb.16.4.1567.
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Retinoic acid (RA) inhibits adipocyte differentiation of 3T3-L1 preadipocytes but is effective only early in adipogenesis. RA prevented induction of the adipogenic factors PPARgamma and C/EBPalpha. Using receptor-specific ligands, we determined that the effects of RA were mediated by liganded RA receptors (RARs) rather than retinoid X receptors. Preadipocytes expressed primarily RARalpha and RARgamma; during adipocyte differentiation, RARalpha gene expression was nearly constant, whereas RARgamma1 mRNA and protein levels dramatically decreased. Ectopic expression of RARgamma1 extended the period of effectiveness of RA by 24 to 48h; RARalpha expression had a similar effect, suggesting functional redundancy of RAR subtypes. Remarkably, RA inhibited differentiation when added after PPARgamma1 and PPARgamma2 proteins had already been expressed and resulted in the loss of PPARgamma proteins from cells. By 72 to 96 h after the induction of differentiation, RA failed to prevent differentiation of even ectopic-RAR-expressing cells. Thus, the unresponsiveness of 3T3-L1 preadipocytes to RA after the induction of differentiation is initially due to the reduction in cellular RAR concentration rather than to the induction of PPARgamma. At later times cells continue along the differentiation pathway in a manner which is RA and RAR independent.
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MORA, Alfonso, Christopher LIPINA, François TRONCHE, Calum SUTHERLAND, and Dario R. ALESSI. "Deficiency of PDK1 in liver results in glucose intolerance, impairment of insulin-regulated gene expression and liver failure." Biochemical Journal 385, no. 3 (January 24, 2005): 639–48. http://dx.doi.org/10.1042/bj20041782.
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The liver plays an important role in insulin-regulated glucose homoeostasis. To study the function of the PDK1 (3-phosphoinositide-dependent protein kinase-1) signalling pathway in mediating insulin's actions in the liver, we employed CRE recombinase/loxP technology to generate L(liver)-PDK1−/− mice, which lack expression of PDK1 in hepatocytes and in which insulin failed to induce activation of PKB in liver. The L-PDK1−/− mice were not insulin-intolerant, possessed normal levels of blood glucose and insulin under normal feeding conditions, but were markedly glucose-intolerant when injected with glucose. The L-PDK1−/− mice also possessed 10-fold lower levels of hepatic glycogen compared with control littermates, and were unable to normalize their blood glucose levels within 2 h after injection of insulin. The glucose intolerance of the L-PDK1−/− mice may be due to an inability of glucose to suppress hepatic glucose output through the gluconeogenic pathway, since the mRNA encoding hepatic PEPCK (phosphoenolpyruvate carboxykinase), G6Pase (glucose-6-phosphatase) and SREBP1 (sterol-regulatory-element-binding protein 1), which regulate gluconeogenesis, are no longer controlled by feeding. Furthermore, three other insulin-controlled genes, namely IGFBP1 (insulin-like-growth-factor-binding protein-1), IRS2 (insulin receptor substrate 2) and glucokinase, were regulated abnormally by feeding in the liver of PDK1-deficient mice. Finally, the L-PDK1−/− mice died between 4–16 weeks of age due to liver failure. These results establish that the PDK1 signalling pathway plays an important role in regulating glucose homoeostasis and controlling expression of insulin-regulated genes. They suggest that a deficiency of the PDK1 pathway in the liver could contribute to development of diabetes, as well as to liver failure.
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Aydemir, Gamze, Marta Domínguez, Angel R. de Lera, Johanna Mihaly, Dániel Törőcsik, and Ralph Rühl. "Apo-14´-Carotenoic Acid Is a Novel Endogenous and Bioactive Apo-Carotenoid." Nutrients 11, no. 9 (September 4, 2019): 2084. http://dx.doi.org/10.3390/nu11092084.
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Carotenoids can be metabolized to various apo-carotenoids and retinoids. Apo-15´-carotenoic acid (retinoic acid, RA) is a potent activator of the retinoic acid receptor (RAR) in its all-trans- (ATRA) and 9-cis- (9CRA) forms. In this study we show firstly, that apo-14´-carotenoic acid (A14CA), besides retinoic acids, is present endogenously and with increased levels in the human organism after carrot juice supplementation rich in β-carotene. All-trans-A14C (ATA14CA) is just a moderate activator of RAR-transactivation in reporter cell lines but can potently activate retinoic acid response element (RARE)-mediated signalling in DR5/RARE-reporter mice and potently increase retinoid-reporter target gene expression in ATA14CA-supplemented mice and treated MM6 cells. Further metabolism to all-trans-13,14-dihydroretinoic acid (ATDHRA) may be the key for its potent effects on retinoid target gene activation in ATA14CA-treated MM6 cells and in liver of supplemented mice. We conclude that besides RAs, there are alternative ways to activate RAR-response pathways in the mammalian organism. ATA14CA alone and in combination with its metabolite ATDHRA may be an alternative pathway for potent RAR-mediated signalling.
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Song, Yingxia, Atsushi Kurose, Renshi Li, Tomoki Takeda, Yuko Onomura, Takayuki Koga, Junpei Mutoh, Takumi Ishida, Yoshitaka Tanaka, and Yuji Ishii. "Ablation of Selenbp1 Alters Lipid Metabolism via the Pparα Pathway in Mouse Kidney." International Journal of Molecular Sciences 22, no. 10 (May 19, 2021): 5334. http://dx.doi.org/10.3390/ijms22105334.
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Selenium-binding protein 1 (Selenbp1) is a 2,3,7,8-tetrechlorodibenzo-p-dioxin inducible protein whose function is yet to be comprehensively elucidated. As the highly homologous isoform, Selenbp2, is expressed at low levels in the kidney, it is worthwhile comparing wild-type C57BL mice and Selenbp1-deficient mice under dioxin-free conditions. Accordingly, we conducted a mouse metabolomics analysis under non-dioxin-treated conditions. DNA microarray analysis was performed based on observed changes in lipid metabolism-related factors. The results showed fluctuations in the expression of numerous genes. Real-time RT-PCR confirmed the decreased expression levels of the cytochrome P450 4a (Cyp4a) subfamily, known to be involved in fatty acid ω- and ω-1 hydroxylation. Furthermore, peroxisome proliferator-activated receptor-α (Pparα) and retinoid-X-receptor-α (Rxrα), which form a heterodimer with Pparα to promote gene expression, were simultaneously reduced. This indicated that reduced Cyp4a expression was mediated via decreased Pparα and Rxrα. In line with this finding, increased levels of leukotrienes and prostaglandins were detected. Conversely, decreased hydrogen peroxide levels and reduced superoxide dismutase (SOD) activity supported the suppression of the renal expression of Sod1 and Sod2 in Selenbp1-deficient mice. Therefore, we infer that ablation of Selenbp1 elicits oxidative stress caused by increased levels of superoxide anions, which alters lipid metabolism via the Pparα pathway.
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Hanley, Timothy M., Heather L. B. Kiefer, Aletta C. Schnitzler, Jennifer E. Marcello, and Gregory A. Viglianti. "Retinoid-Dependent Restriction of Human Immunodeficiency Virus Type 1 Replication in Monocytes/Macrophages." Journal of Virology 78, no. 6 (March 15, 2004): 2819–30. http://dx.doi.org/10.1128/jvi.78.6.2819-2830.2004.
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ABSTRACT Vitamin A deficiency has been correlated with increased severity of human immunodeficiency virus type 1 (HIV-1)-associated disease. Moreover, vitamin A supplementation can reduce AIDS-associated morbidity and mortality. Our group and others have shown that retinoids, the bioactive metabolites of vitamin A, repress HIV-1 replication in monocytic cell lines and primary macrophages by blocking long-terminal-repeat (LTR)-directed transcription. Based on these studies, we hypothesize that retinoids are natural repressors of HIV-1 in vivo. We show here that all-trans-retinoic acid (RA)-mediated repression of HIV-1 activation requires pretreatment for at least 12 h and is blocked by the protein synthesis inhibitors cycloheximide and puromycin. Studies of the kinetics of RA-mediated repression in U1 cells and primary monocyte-derived macrophages (MDMs) reveal that the repressive effects of RA on HIV-1 expression are long-lasting but reversible. We demonstrate that HIV-1 expression is activated when U1 cells or MDMs are cultured in retinoid-free synthetic medium and show that physiological concentrations of RA repress this activation. In addition, the synthetic pan-retinoic acid receptor antagonist BMS-204 493 activates HIV-1 replication in U1 cells in a dose-dependent manner, suggesting that RA-induced transactivation of cellular gene expression is required for HIV-1 repression. Together, these data support the hypothesis that retinoids present in tissue culture media in vitro and serum in vivo maintain HIV-1 in a transcriptionally repressed state in monocytes/macrophages.
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Anchan, R. M., D. P. Drake, C. F. Haines, E. A. Gerwe, and A. S. LaMantia. "Erratum: Disruption of local retinoid-mediated gene expression accompanies abnormal development in the mammalian olfactory pathway. J. Comp. Neurol.379:171-184." Journal of Comparative Neurology 384, no. 2 (July 28, 1997): 321. http://dx.doi.org/10.1002/(sici)1096-9861(19970728)384:2<321::aid-cne11>3.0.co;2-l.
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