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Sample records for nuclear receptor coactivator

  1. SRC-3 Has a Role in Cancer Other Than as a Nuclear Receptor Coactivator

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    Gang Ma, Yu Ren, Ke Wang, Jianjun He

    2011-01-01

    Full Text Available Steroid receptor coactivator-3 (SRC-3, also known as AIB1, is a member of the p160 steroid receptor coactivator family. Since SRC-3 was found to be amplified in breast cancer in 1997, the role of SRC-3 in cancer has been broadly investigated. SRC-3 initially was identified as a transcriptional coactivator for nuclear receptors such as the estrogen receptor (ER, involved in the proliferation of hormone-dependent cancers. However, increasing clinical evidence shows that dysregulation of SRC-3 expression in several human hormone-independent cancers is correlated with pathological factors and clinical prognosis. Recently, both in vivo and in vitro studies demonstrate that SRC-3 may influence a number of cancer cellular processes in several ways independent of nuclear receptor signaling. In addition, an SRC-3 transgenic mice model shows that SRC-3 induces tumors in several mouse tissues. These results indicate that the role of SRC-3 in cancer is not just as a nuclear receptor coactivator. The focus of this review is to examine possible SRC-3 roles in cancer, other than as a nuclear receptor coactivator.

  2. Diverse coactivator recruitment through differential PPARγ nuclear receptor agonism

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    Fernando Lizcano; Diana Vargas

    2013-01-01

    The PPARγ nuclear receptor regulates the expression of genes involved in lipid and carbohydrate metabolism, and it has protective effects in some patients with type 2 diabetes. Nevertheless, the therapeutic value of the PPARγ nuclear receptor protein is limited due to the secondary effects of some PPARγ ligands. Because the downstream effects of PPARγ are determined by the binding of specific cofactors that are mediated by ligand-induced conformational changes, we evaluate...

  3. CIA, a novel estrogen receptor coactivator with a bifunctional nuclear receptor interacting determinant.

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    Sauvé, F; McBroom, L D; Gallant, J; Moraitis, A N; Labrie, F; Giguère, V

    2001-01-01

    Coregulators for nuclear receptors (NR) are factors that either enhance or repress their transcriptional activity. Both coactivators and corepressors have been shown to use similar but functionally distinct NR interacting determinants containing the core motifs LxxLL and PhixxPhiPhi, respectively. These interactions occur through a hydrophobic cleft located on the surface of the ligand-binding domain (LBD) of the NR and are regulated by ligand-dependent activation function 2 (AF-2). In an effort to identify novel coregulators that function independently of AF-2, we used the LBD of the orphan receptor RVR (which lacks AF-2) as bait in a yeast two-hybrid screen. This strategy led to the cloning of a nuclear protein referred to as CIA (coactivator independent of AF-2 function) that possesses both repressor and activator functions. Strikingly, we observed that CIA not only interacts with RVR and Rev-ErbAalpha in a ligand-independent manner but can also form complexes with estrogen receptor alpha (ERalpha) and ERbeta in vitro and enhances ERalpha transcriptional activity in the presence of estradiol (E(2)). CIA-ERalpha interactions were found to be independent of AF-2 and enhanced by the antiestrogens EM-652 and ICI 182,780 but not by 4-hydroxytamoxifen and raloxifene. We further demonstrate that CIA-ERalpha interactions require the presence within CIA of a novel bifunctional NR recognition determinant containing overlapping LxxLL and PhixxPhiPhi motifs. The identification and functional characterization of CIA suggest that hormone binding can create a functional coactivator interaction interface in the absence of AF-2.

  4. Diverse coactivator recruitment through differential PPARγ nuclear receptor agonism

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    Fernando Lizcano

    2013-01-01

    Full Text Available The PPARγ nuclear receptor regulates the expression of genes involved in lipid and carbohydrate metabolism, and it has protective effects in some patients with type 2 diabetes. Nevertheless, the therapeutic value of the PPARγ nuclear receptor protein is limited due to the secondary effects of some PPARγ ligands. Because the downstream effects of PPARγ are determined by the binding of specific cofactors that are mediated by ligand-induced conformational changes, we evaluated the differential effects of various ligands on the binding of certain cofactors associated with PPARγ. The ligands used were rosiglitazone for treating type 2 diabetes and telmisartan for treating arterial hypertension. Functional, phenotypic, and molecular studies were conducted on pre-adipocyte 3T3-L1 and functional studies in U2OS cells. The moderating influence of various cofactor families was evaluated using transient transfection assays. Our findings confirm that telmisartan has a partial modulating effect on PPARγ activity compared to rosiglitazone. The cofactors SRC1 and GRIP1 mediate the activity of telmisartan and rosiglitazone and partially determine the difference in their effects. Studying the modulating activity of these cofactors can provide interesting insights for developing new therapeutic approaches for certain metabolic diseases.

  5. Multiple functions and essential roles of nuclear receptor coactivators of bHLH-PAS family.

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    Pecenova, L; Farkas, Robert

    2016-07-01

    Classical non-peptide hormones, such as steroids, retinoids, thyroid hormones, vitamin D3 and their derivatives including prostaglandins, benzoates, oxysterols, and bile acids, are collectively designated as small lipophilic ligands, acting via binding to the nuclear receptors (NRs). The NRs form a large superfamily of transcription factors that participate virtually in every key biological process. They control various aspects of animal development, fertility, gametogenesis, and numerous metabolic pathways, and can be misregulated in many types of cancers. Their enormous functional plasticity, as transcription factors, relates in part to NR-mediated interactions with plethora of coregulatory proteins upon ligand binding to their ligand binding domains (LBD), or following covalent modification. Here, we review some general views of a specific group of NR coregulators, so-called nuclear receptor coactivators (NRCs) or steroid receptor coactivators (SRCs) and highlight some of their unique functions/roles, which are less extensively mentioned and discussed in other reviews. We also try to pinpoint few neglected moments in the cooperative action of SRCs, which may also indicate their variable roles in the hormone-independent signaling pathways.

  6. Cloning, genomic organization, and expression analysis of zebrafish nuclear receptor coactivator, TIF2.

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    Tan, Jee-Hian; Quek, Sue-Ing; Chan, Woon-Khiong

    2005-01-01

    Thyroid hormone receptors (TRs) are involved in numerous diverse biological processes such as growth and differentiation, thermogenesis, neurulation, homeostasis, and metamorphosis. In zebrafish, TRbeta1 has been implicated to be involved in the obligatory embryonic-to-larval transitory phase. In order to understand if nuclear receptor coactivators could modulate the transcriptional activities of TRs during this transitory phase, the transcriptionary intermediary factor 2 (TIF2), a member of the p160 coactivator, was isolated from zebrafish. The zebrafish tif2 cDNA encodes a polypeptide of 1,505 amino acids. The tif2 gene is made up of 23 exons with the AUG and stop codon located in Exon IV and XXIII, respectively. The overall genomic organization of human and zebrafish tif2 genes are very similar. Four tif2 isoforms were identified by RT-PCR. The N-terminus mRNA variants are generated as a result of multiple initiation start sites located upstream of the noncoding Exon I and Exon II. The C-terminus isoforms, E20a and E20b, resulted from the alternative splicing of Exon XX. Although E20a and E20b isoforms were ubiquitously expressed, they were very highly expressed in reproductive tissues. The availability of TIF2 cDNA will allow the analysis of its functional roles in mediating the actions of TRs in various aspects of zebrafish developmental biology.

  7. Phenotypic alterations in breast cancer cells overexpressing the nuclear receptor co-activator AIB1

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    Azorsa David O

    2003-09-01

    Full Text Available Abstract Background Estrogen signaling plays a critical role in a number of normal physiological processes and has important implications in the treatment of breast cancer. The p160 nuclear receptor coactivator, AIB1 (amplified in breast cancer 1, is frequently amplified and overexpressed in human breast cancer and has been shown to enhance estrogen-dependent transactivation. Methods To better understand the molecular and physiological consequences of AIB1 overexpression in breast cancer cells, an AIB1 cDNA was transfected into the low AIB1 expressing, estrogen-receptor (ER negative breast cancer cell line, MDA-MB-436. The features of a derivative cell line, designated 436.1, which expresses high levels of AIB1, are described and compared with the parental cell line. Results A significant increase in the levels of CREB binding protein (CBP was observed in 436.1 cells and immunofluorescent staining revealed altered AIB1 and CBP staining patterns compared to the parental cells. Further, transient transfection assays demonstrated that the overall estrogen-dependent transactivation in 436.1 cells is approximately 20-fold higher than the parental cells and the estrogen dose-response curve is repositioned to the right. Finally, cDNA microarray analysis of approximately 7,100 cDNAs identified a number of differentially expressed genes in the 436.1 cells. Conclusion These observations lend insight into downstream signaling pathways that are influenced by AIB1.

  8. A novel nuclear role for the Vav3 nucleotide exchange factor in androgen receptor coactivation in prostate cancer.

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    Rao, S; Lyons, L S; Fahrenholtz, C D; Wu, F; Farooq, A; Balkan, W; Burnstein, K L

    2012-02-01

    Increased androgen receptor (AR) transcriptional activity mediated by coactivator proteins may drive castration-resistant prostate cancer (CRPC) growth. Vav3, a Rho GTPase guanine nucleotide exchange factor (GEF), is overexpressed in human prostate cancers, particularly in models of CRPC progression. Vav3 coactivates AR in a Vav3 pleckstrin homology (PH) domain-dependent but GEF-independent manner. Ectopic expression of Vav3 in androgen-dependent human prostate cancer cells conferred robust castration-resistant xenograft tumor growth. Vav3 but not a Vav3 PH mutant greatly stimulated interaction between the AR amino and carboxyl termini (N-C interaction), which is required for maximal receptor transcriptional activity. Vav3 was distributed between the cytoplasm and nucleus with nuclear localization-dependent on the Vav3 PH domain. Membrane targeting of Vav3 abolished Vav3 potentiation of AR activity, whereas nuclear targeting of a Vav3 PH mutant rescued AR coactivation, suggesting that nuclear localization is an important function of the Vav3 PH domain. A nuclear role for Vav3 was further demonstrated by sequential chromatin immunoprecipitation assays, which revealed that Vav3 and AR were recruited to the same transcriptional complexes of an AR target gene enhancer. These data demonstrate the importance of Vav3 in CRPC and define a novel nuclear function of Vav3 in regulating AR activity.

  9. A muscle-specific knockout implicates nuclear receptor coactivator MED1 in the regulation of glucose and energy metabolism.

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    Chen, Wei; Zhang, Xiaoting; Birsoy, Kivanc; Roeder, Robert G

    2010-06-01

    As conventional transcriptional factors that are activated in diverse signaling pathways, nuclear receptors play important roles in many physiological processes that include energy homeostasis. The MED1 subunit of the Mediator coactivator complex plays a broad role in nuclear receptor-mediated transcription by anchoring the Mediator complex to diverse promoter-bound nuclear receptors. Given the significant role of skeletal muscle, in part through the action of nuclear receptors, in glucose and fatty acid metabolism, we generated skeletal muscle-specific Med1 knockout mice. Importantly, these mice show enhanced insulin sensitivity and improved glucose tolerance as well as resistance to high-fat diet-induced obesity. Furthermore, the white muscle of these mice exhibits increased mitochondrial density and expression of genes specific to type I and type IIA fibers, indicating a fast-to-slow fiber switch, as well as markedly increased expression of the brown adipose tissue-specific UCP-1 and Cidea genes that are involved in respiratory uncoupling. These dramatic results implicate MED1 as a powerful suppressor in skeletal muscle of genetic programs implicated in energy expenditure and raise the significant possibility of therapeutical approaches for metabolic syndromes and muscle diseases through modulation of MED1-nuclear receptor interactions.

  10. Pregnane X receptor (PXR-mediated gene repression and cross-talk of PXR with other nuclear receptors via coactivator interactions

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    Petr Pavek

    2016-11-01

    Full Text Available Pregnane X receptor is a ligand-activated nuclear receptor that mainly controls inducible expression of xenobiotics handling genes including biotransformation enzymes and drug transporters. Nowadays it is clear that PXR is also involved in regulation of intermediate metabolism through trans-activation and trans-repression of genes controlling glucose, lipid, cholesterol, bile acid and bilirubin homeostasis. In these processes PXR cross-talks with other nuclear receptors. Accumulating evidence suggests that the cross-talk is often mediated by competing for common coactivators or by disruption of coactivation and activity of other transcription factors by the ligand-activated PXR. In this respect mainly PXR-CAR and PXR-HNF4α interference have been reported and several cytochrome P450 enzymes (such as CYP7A1 and CYP8B1, phase II enzymes (SULT1E1, Gsta2, Ugt1a1, drug and endobiotic transporters (OCT1, Mrp2, Mrp3, Oatp1a and Oatp4 as well as intermediate metabolism enzymes (PEPCK1 and G6Pase have been shown as down-regulated genes after PXR activation. In this review, I summarize our current knowledge of PXR-mediated repression and coactivation interference in PXR-controlled gene expression regulation.

  11. Pregnane X Receptor (PXR)-Mediated Gene Repression and Cross-Talk of PXR with Other Nuclear Receptors via Coactivator Interactions

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    Pavek, Petr

    2016-01-01

    Pregnane X receptor is a ligand-activated nuclear receptor (NR) that mainly controls inducible expression of xenobiotics handling genes including biotransformation enzymes and drug transporters. Nowadays it is clear that PXR is also involved in regulation of intermediate metabolism through trans-activation and trans-repression of genes controlling glucose, lipid, cholesterol, bile acid, and bilirubin homeostasis. In these processes PXR cross-talks with other NRs. Accumulating evidence suggests that the cross-talk is often mediated by competing for common coactivators or by disruption of coactivation and activity of other transcription factors by the ligand-activated PXR. In this respect mainly PXR-CAR and PXR-HNF4α interference have been reported and several cytochrome P450 enzymes (such as CYP7A1 and CYP8B1), phase II enzymes (SULT1E1, Gsta2, Ugt1a1), drug and endobiotic transporters (OCT1, Mrp2, Mrp3, Oatp1a, and Oatp4) as well as intermediate metabolism enzymes (PEPCK1 and G6Pase) have been shown as down-regulated genes after PXR activation. In this review, I summarize our current knowledge of PXR-mediated repression and coactivation interference in PXR-controlled gene expression regulation. PMID:27932985

  12. Orexin excites rat inferior vestibular nuclear neurons via co-activation of OX1 and OX 2 receptors.

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    Yu, Lei; Zhang, Xiao-Yang; Chen, Zhang-Peng; Zhuang, Qian-Xing; Zhu, Jing-Ning; Wang, Jian-Jun

    2015-06-01

    Orexin deficiency results in cataplexy, a motor deficit characterized by sudden loss of muscle tone, strongly indicating an active role of central orexinergic system in motor control. However, effects of orexin on neurons in central motor structures are still largely unknown. Our previous studies have revealed that orexin excites neurons in the cerebellar nuclei and lateral vestibular nucleus, two important subcortical motor centers for control of muscle tone. Here, we report that both orexin-A and orexin-B depolarizes and increases the firing rate of neurons in the inferior vestibular nucleus (IVN), the largest nucleus in the vestibular nuclear complex and holding an important position in integration of information signals in the control of body posture. TTX does not block orexin-induced excitation on IVN neurons, suggesting a direct postsynaptic action of the neuropeptide. Furthermore, bath application of orexin induces an inward current on IVN neurons in a concentration-dependent manner. SB334867 and TCS-OX2-29, specific OX1 and OX2 receptor antagonists, blocked the excitatory effect of orexin, and [Ala(11), D-Leu(15)]-orexin B, a selective OX2 receptor agonist, mimics the orexin-induced inward current on IVN neurons. qPCR and immunofluorescence results show that both OX1 and OX2 receptor mRNAs and proteins are expressed and localized in the rat IVN. These results demonstrate that orexin excites the IVN neurons by co-activation of both OX1 and OX2 receptors, suggesting that via the direct modulation on the IVN, the central orexinergic system may actively participate in the central vestibular-mediated postural and motor control.

  13. Nuclear receptor co-activators and HER-2/neu are upregulated in breast cancer patients during neo-adjuvant treatment with aromatase inhibitors

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    Flågeng, M Hauglid; Haugan Moi, L L; Dixon, J M; Geisler, J; Lien, E A; Miller, W R; Lønning, P E; Mellgren, G

    2009-01-01

    Background: Acquired resistance to endocrine therapy in breast cancer is poorly understood. Characterisation of the molecular response to aromatase inhibitors in breast cancer tissue may provide important information regarding development of oestrogen hypersensitivity. Methods: We examined the expression levels of nuclear receptor co-regulators, the orphan nuclear receptor liver receptor homologue-1 and HER-2/neu growth factor receptor using real-time RT-PCR before and after 13–16 weeks of primary medical treatment with the aromatase inhibitors anastrozole or letrozole. Results: mRNA expression of the steroid receptor co-activator 1 (SRC-1) and peroxisome-proliferator-activated receptor γ co-activator-1α (PGC-1α) was correlated (P=0.002), and both co-activators increased during treatment in the patient group as a whole (P=0.008 and P=0.032, respectively), as well as in the subgroup of patients achieving an objective treatment response (P=0.002 and P=0.006). Although we recorded no significant change in SRC-3/amplified in breast cancer 1 level, the expression correlated positively to the change of SRC-1 (P=0.002). Notably, we recorded an increase in HER-2/neu levels during therapy in the total patient group (18 out of 26; P=0.016), but in particular among responders (15 out of 21; P=0.008). Conclusion: Our results show an upregulation of co-activator mRNA and HER-2/neu during treatment with aromatase inhibitors. These mechanisms may represent an early adaption of the breast cancer cells to oestrogen deprivation in vivo. PMID:19755984

  14. Nuclear pyruvate kinase M2 complex serves as a transcriptional coactivator of arylhydrocarbon receptor.

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    Matsuda, Shun; Adachi, Jun; Ihara, Masaru; Tanuma, Nobuhiro; Shima, Hiroshi; Kakizuka, Akira; Ikura, Masae; Ikura, Tsuyoshi; Matsuda, Tomonari

    2016-01-29

    Pyruvate kinase M2 (PKM2) and pyruvate dehydrogenase complex (PDC) regulate production of acetyl-CoA, which functions as an acetyl donor in diverse enzymatic reactions, including histone acetylation. However, the mechanism by which the acetyl-CoA required for histone acetylation is ensured in a gene context-dependent manner is not clear. Here we show that PKM2, the E2 subunit of PDC and histone acetyltransferase p300 constitute a complex on chromatin with arylhydrocarbon receptor (AhR), a transcription factor associated with xenobiotic metabolism. All of these factors are recruited to the enhancer of AhR-target genes, in an AhR-dependent manner. PKM2 contributes to enhancement of transcription of cytochrome P450 1A1 (CYP1A1), an AhR-target gene, acetylation at lysine 9 of histone H3 at the CYP1A1 enhancer. Site-directed mutagenesis of PKM2 indicates that this enhancement of histone acetylation requires the pyruvate kinase activity of the enzyme. Furthermore, we reveal that PDC activity is present in nuclei. Based on these findings, we propose a local acetyl-CoA production system in which PKM2 and PDC locally supply acetyl-CoA to p300 from abundant PEP for histone acetylation at the gene enhancer, and our data suggest that PKM2 sensitizes AhR-mediated detoxification in actively proliferating cells such as cancer and fetal cells.

  15. The nuclear hormone receptor coactivator NRC is a pleiotropic modulator affecting growth, development, apoptosis, reproduction, and wound repair.

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    Mahajan, Muktar A; Das, Sharmistha; Zhu, Hong; Tomic-Canic, Marjana; Samuels, Herbert H

    2004-06-01

    Nuclear hormone receptor coregulator (NRC) is a 2,063-amino-acid coregulator of nuclear hormone receptors and other transcription factors (e.g., c-Fos, c-Jun, and NF-kappaB). We and others have generated C57BL/6-129S6 hybrid (C57/129) NRC(+/-) mice that appear outwardly normal and grow and reproduce. In contrast, homozygous deletion of the NRC gene is embryonic lethal. NRC(-/-) embryos are always smaller than NRC(+/+) embryos, and NRC(-/-) embryos die between 8.5 and 12.5 days postcoitus (dpc), suggesting that NRC has a pleotrophic effect on growth. To study this, we derived mouse embryonic fibroblasts (MEFs) from 12.5-dpc embryos, which revealed that NRC(-/-) MEFs exhibit a high rate of apoptosis. Furthermore, a small interfering RNA that targets mouse NRC leads to enhanced apoptosis of wild-type MEFs. The finding that C57/129 NRC(+/-) mice exhibit no apparent phenotype prompted us to develop 129S6 NRC(+/-) mice, since the phenotype(s) of certain gene deletions may be strain dependent. In contrast with C57/129 NRC(+/-) females, 20% of 129S6 NRC(+/-) females are infertile while 80% are hypofertile. The 129S6 NRC(+/-) males produce offspring when crossed with wild-type 129S6 females, although fertility is reduced. The 129S6 NRC(+/-) mice tend to be stunted in their growth compared with their wild-type littermates and exhibit increased postnatal mortality. Lastly, both C57/129 NRC(+/-) and 129S6 NRC(+/-) mice exhibit a spontaneous wound healing defect, indicating that NRC plays an important role in that process. Our findings reveal that NRC is a coregulator that controls many cellular and physiologic processes ranging from growth and development to reproduction and wound repair.

  16. Identification and function of coactivator of estrogen receptor: ERIAP

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    孟庆慧; 周立新; 曹建平; 高斌; 邵荣光; 李及友; 樊赛军

    2003-01-01

    Estrogen receptor (ER), one member of nuclear hormone receptor (NR) family, is an estrogen-dependent transcriptional factor that plays an important role in development, progression and treatment of breast cancer. Transcriptional co-factors (co-activators and co-repressors) are critical for ER to transduce hormone and metabolic signaling to target genes. A number of functional and structural studies have elucidated the precise mechanisms of co-activator interaction with the ligand-inducible activation domain in ER via one and several LXXLL motifs (where X is any amino acid) known as NR-Box. By the yeast two-hybrid system we have identified a novel ER-αinteracting protein ERIAP (Estrogen Receptor Interacting and Activating Protein) which contains two consensus LXXLL motifs. ERIAP associated with ER-α in a ligand-dependent manner, as demonstrated by in vivo immunoprecipitation and in vitro GST capture assays. The two NR boxes were essential for ERIAP interaction with ER-α. Furthermore, ERIAP specifically enhanced ligand-mediated ER-α transcriptional activity in a dose-dependent fasion and increased the expression of estrogen-responsive gene pS2. Thus, our present findings indicate that ERIAP funcions as a new coactivator for ER-α transcriptional activity, which may play an important role in development and progression of breast cancer.

  17. DTL, the Drosophila homolog of PIMT/Tgs1 nuclear receptor coactivator-interacting protein/RNA methyltransferase, has an essential role in development.

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    Komonyi, Orbán; Pápai, Gábor; Enunlu, Izzet; Muratoglu, Selen; Pankotai, Tibor; Kopitova, Darija; Maróy, Péter; Udvardy, Andor; Boros, Imre

    2005-04-01

    We describe a novel Drosophila gene, dtl (Drosophila Tat-like), which encodes a 60-kDa protein with RNA binding activity and a methyltransferase (MTase) domain. Dtl has an essential role in Drosophila development. The homologs of DTL recently described include PIMT (peroxisome proliferator-activated receptor-interacting protein with a methyltransferase domain), an RNA-binding protein that interacts with and enhances the nuclear receptor coactivator function, and TGS1, the methyltransferase involved in the formation of the 2,2,7-trimethylguanosine (m3G) cap of non-coding small RNAs. DTL is expressed throughout all of the developmental stages of Drosophila. The dtl mRNA has two ORFs (uORF and dORF). The product of dORF is the 60-kDa PIMT/TGS1 homolog protein that is translated from an internal AUG located 538 bp downstream from the 5' end of the message. This product of dtl is responsible for the formation of the m3G cap of small RNAs of Drosophila. Trimethylguanosine synthase activity is essential in Drosophila. The deletion in the dORF or point mutation in the putative MTase active site results in a reduced pool of m3G cap-containing RNAs and lethality in the early pupa stage. The 5' region of the dtl message also has the coding capacity (uORF) for a 178 amino acid protein. For complete rescue of the lethal phenotype of dtl mutants, the presence of the entire dtl transcription unit is required. Transgenes that carry mutations within the uORF restore the MTase activity but result in only partial rescue of the lethal phenotype. Interestingly, two transgenes bearing a mutation in uORF or dORF in trans can result in complete rescue.

  18. El coactivador de receptores nucleares RAC3 tiene un rol protector de la Apoptosis inducida por distintos estímulos RAC3 nuclear receptor co-activator has a protective role in the apoptosis induced by different stimuli

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    Georgina P. Coló

    2007-10-01

    Full Text Available RAC3 pertenece a la familia de coactivadores de receptores nucleares p160, y se encuentra sobreexpresado en varios tumores. Demostramos previamente que RAC3 es coactivador del factor de transcripción anti-apoptótico NF-kapa;B. En este trabajo investigamos su rol en la apoptosis inducida por H2O2 en una línea celular no tumoral derivada de riñón embrionario humano (HEK293, y por el ligando inductor de apoptosis relacionado a TNF (TRAIL en una línea de leucemia mieloide crónica humana (K562, naturalmente resistente a la muerte por este estímulo. Observamos que las células tumorales K562 poseen niveles altos de RAC3 comparados con las células no tumorales HEK293. La sobreexpresión normal de coactivador o por transfección, inhibe la apoptosis mediante una disminución de la activación de caspasas, translocación del factor inductor de apoptosis (AIF al núcleo, aumento de la actividad de NF-kapa;B y las quinasas AKT y p38 y disminución de la quinasa ERK. Lo opuesto fue observado por disminución de RAC3 mediante la técnica de ARN interferente (RNAi en K562, aumentando así la apoptosis inducida por TRAIL. Estas evidencias sugieren que una sobreexpresión de RAC3 contribuye al desarrollo de tumores, participando en las cascadas que controlan la muerte celular por mecanismos no estrictamente dependientes de hormonas esteroideas y/o de acetilación, constituyendo esto un posible blanco de ataque para el tratamiento de tumores.RAC3 belongs to the family of p160 nuclear receptors coactivators and it is over-expressed in several tumors. We have previously shown that RAC3 is a NF-kappa;B coactivator. In this paper, we investigated the role of RAC3 in cell-sensitivity to apoptosis, using H2O2 in the human embryonic kidney cell line (HEK293, and tumor necrosis factor-related apoptosis inducing ligand (TRAIL in a human chronic myeloid leukemia cell line (K562 naturally resistant to TRAIL. We observed that the tumoral K562 cells have high levels

  19. The Role of Steroid Receptor Coactivator-1 in Breast Cancer

    Science.gov (United States)

    2001-06-01

    Tsai, B.W. O’Malley, The Angelman syndrome -associated protein, E6-AP, is a coactivator for the nuclear hormone recep-the profusion of coactivators known...deletion of the SRC-1 gene in our labo- The hormone-dependent recruitment of co-activators by NRs ratory. The SRC-1 null phenotype is characterized by...coactivators, the phenotype of the SRC- SRC-I complex, Cell 97 (1999) 17-27. I mouse being the most obvious testament in this [11] V.V. Ogryzko, R.L

  20. Molecular cloning and properties of a full-length putative thyroid hormone receptor coactivator.

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    Takeshita, A; Yen, P M; Misiti, S; Cardona, G R; Liu, Y; Chin, W W

    1996-08-01

    Thyroid hormone receptors (TRs) are ligand-dependent transcription factors that regulate target gene transcription. The conserved carboxy-terminal region of the ligand-binding domain (AF-2) has been thought to play a critical role in mediating ligand-dependent transactivation by the interaction with coactivator(s). Using bacterially-expressed TR as a probe, far-Western-based expression cDNA library screening identified cDNAs that encode, in part, the recently reported partial steroid receptor coactivator-1 (SRC-1) sequence. Additional work, including 5' RACE, has characterized a full-length cDNA that encodes a approximately 160 kD protein as a putative thyroid hormone receptor coactivator (F-SRC-1). In vitro binding studies show that F-SRC-1 binds to a variety of nuclear hormone receptors in a ligand-dependent manner, along with TBP and TFIIB, suggesting that F-SRC-1 may play a role as a bridging molecule between nuclear hormone receptors and general transcription factors. Interestingly, AF-2 mutants also retain ligand-dependent interaction with F-SRC-1. Although F-SRC-1 recognizes the ligand-induced conformational changes of nuclear hormone receptors, our observations suggest that F-SRC-1 may bind directly with subregion(s) in nuclear hormone receptors other than the AF-2 region.

  1. Components of the CCR4-NOT complex function as nuclear hormone receptor coactivators via association with the NRC-interacting Factor NIF-1.

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    Garapaty, Shivani; Mahajan, Muktar A; Samuels, Herbert H

    2008-03-14

    CCR4-NOT is an evolutionarily conserved, multicomponent complex known to be involved in transcription as well as mRNA degradation. Various subunits (e.g. CNOT1 and CNOT7/CAF1) have been reported to be involved in influencing nuclear hormone receptor activities. Here, we show that CCR4/CNOT6 and RCD1/CNOT9, members of the CCR4-NOT complex, potentiate nuclear receptor activity. RCD1 interacts in vivo and in vitro with NIF-1 (NRC-interacting factor), a previously characterized nuclear receptor cotransducer that activates nuclear receptors via its interaction with NRC. As with NIF-1, RCD1 and CCR4 do not directly associate with nuclear receptors; however, they enhance ligand-dependent transcriptional activation by nuclear hormone receptors. CCR4 mediates its effect through the ligand binding domain of nuclear receptors and small interference RNA-mediated silencing of endogenous CCR4 results in a marked decrease in nuclear receptor activation. Furthermore, knockdown of CCR4 results in an attenuated stimulation of RARalpha target genes (e.g. Sox9 and HoxA1) as shown by quantitative PCR assays. The silencing of endogenous NIF-1 also resulted in a comparable decrease in the RAR-mediated induction of both Sox9 and HoxA1. Furthermore, CCR4 associates in vivo with NIF-1. In addition, the CCR4-enhanced transcriptional activation by nuclear receptors is dependent on NIF-1. The small interference RNA-mediated knockdown of NIF-1 blocks the ligand-dependent potentiating effect of CCR4. Our results suggest that CCR4 plays a role in the regulation of certain endogenous RARalpha target genes and that RCD1 and CCR4 might mediate their function through their interaction with NIF-1.

  2. Ligand-specific allosteric regulation of coactivator functions of androgen receptor in prostate cancer cells

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    Baek, Sung Hee; Ohgi, Kenneth A.; Nelson, Charles A.; Welsbie, Derek; Chen, Charlie; Sawyers, Charles L.; Rose, David W.; Rosenfeld, Michael G.

    2006-01-01

    The androgen receptor not only mediates prostate development but also serves as a key regulator of primary prostatic cancer growth. Although initially responsive to selective androgen receptor modulators (SARMs), which cause recruitment of the nuclear receptor–corepressor (N-CoR) complex, resistance invariably occurs, perhaps in response to inflammatory signals. Here we report that dismissal of nuclear receptor–corepressor complexes by specific signals or androgen receptor overexpression results in recruitment of many of the cohorts of coactivator complexes that permits SARMs and natural ligands to function as agonists. SARM-bound androgen receptors appear to exhibit failure to recruit specific components of the coactivators generally bound by liganded nuclear receptors, including cAMP response element-binding protein (CBP)/p300 or coactivator-associated arginine methyltransferase 1 (CARM1) to the SARM-bound androgen receptor, although still causing transcriptional activation of androgen receptor target genes. SARM-bound androgen receptors use distinct LXXLL (L, leucine; X, any amino acid) helices in the p160 nuclear receptor interaction domains that may impose selective allosteric effects, providing a component of the molecular basis of differential responses to different classes of ligands by androgen receptor. PMID:16492776

  3. Steroid receptor coactivator-3 regulates glucose metabolism in bladder cancer cells through coactivation of hypoxia inducible factor 1α.

    Science.gov (United States)

    Zhao, Wei; Chang, Cunjie; Cui, Yangyan; Zhao, Xiaozhi; Yang, Jun; Shen, Lan; Zhou, Ji; Hou, Zhibo; Zhang, Zhen; Ye, Changxiao; Hasenmayer, Donald; Perkins, Robert; Huang, Xiaojing; Yao, Xin; Yu, Like; Huang, Ruimin; Zhang, Dianzheng; Guo, Hongqian; Yan, Jun

    2014-04-18

    Cancer cell proliferation is a metabolically demanding process, requiring high glycolysis, which is known as "Warburg effect," to support anabolic growth. Steroid receptor coactivator-3 (SRC-3), a steroid receptor coactivator, is overexpressed and/or amplified in multiple cancer types, including non-steroid targeted cancers, such as urinary bladder cancer (UBC). However, whether SRC-3 regulates the metabolic reprogramming for cancer cell growth is unknown. Here, we reported that overexpression of SRC-3 accelerated UBC cell growth, accompanied by the increased expression of genes involved in glycolysis. Knockdown of SRC-3 reduced the UBC cell glycolytic rate under hypoxia, decreased tumor growth in nude mice, with reduction of proliferating cell nuclear antigen and lactate dehydrogenase expression levels. We further revealed that SRC-3 could interact with hypoxia inducible factor 1α (HIF1α), which is a key transcription factor required for glycolysis, and coactivate its transcriptional activity. SRC-3 was recruited to the promoters of HIF1α-target genes, such as glut1 and pgk1. The positive correlation of expression levels between SRC-3 and Glut1 proteins was demonstrated in human UBC patient samples. Inhibition of glycolysis through targeting HK2 or LDHA decelerated SRC-3 overexpression-induced cell growth. In summary, overexpression of SRC-3 promoted glycolysis in bladder cancer cells through HIF1α to facilitate tumorigenesis, which may be an intriguing drug target for bladder cancer therapy.

  4. Functional interaction of hepatic nuclear factor-4 and peroxisome proliferator-activated receptor-gamma coactivator 1alpha in CYP7A1 regulation is inhibited by a key lipogenic activator, sterol regulatory element-binding protein-1c.

    Science.gov (United States)

    Ponugoti, Bhaskar; Fang, Sungsoon; Kemper, Jongsook Kim

    2007-11-01

    Insulin inhibits transcription of cholesterol 7alpha-hydroxylase (Cyp7a1), a key gene in bile acid synthesis, and the hepatic nuclear factor-4 (HNF-4) site in the promoter was identified as a negative insulin response sequence. Using a fasting/feeding protocol in mice and insulin treatment in HepG2 cells, we explored the inhibition mechanisms. Expression of sterol regulatory element-binding protein-1c (SREBP-1c), an insulin-induced lipogenic factor, inversely correlated with Cyp7a1 expression in mouse liver. Interaction of HNF-4 with its coactivator, peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha), was observed in livers of fasted mice and was reduced after feeding. Conversely, HNF-4 interaction with SREBP-1c was increased after feeding. In vitro studies suggested that SREBP-1c competed with PGC-1alpha for direct interaction with the AF2 domain of HNF-4. Reporter assays showed that SREBP-1c, but not of a SREBP-1c mutant lacking the HNF-4 interacting domain, inhibited HNF-4/PGC-1alpha transactivation of Cyp7a1. SREBP-1c also inhibited PGC-1alpha-coactivation of estrogen receptor, constitutive androstane receptor, pregnane X receptor, and farnesoid X receptor, implying inhibition of HNF-4 by SREBP-1c could extend to other nuclear receptors. In chromatin immunoprecipitation studies, HNF-4 binding to the promoter was not altered, but PGC-1alpha was dissociated, SREBP-1c and histone deacetylase-2 (HDAC2) were recruited, and acetylation of histone H3 was decreased upon feeding. Adenovirus-mediated expression of a SREBP-1c dominant-negative mutant, which blocks the interaction of SREBP-1c and HNF-4, partially but significantly reversed the inhibition of Cyp7a1 after feeding. Our data show that SREBP-1c functions as a non-DNA-binding inhibitor and mediates, in part, suppression of Cyp7a1 by blocking functional interaction of HNF-4 and PGC-1alpha. This mechanism may be relevant to known repression of many other HNF-4 target genes upon

  5. Expression and function of androgen receptor coactivator p44/Mep50/WDR77 in ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Martin Ligr

    Full Text Available Hormones, including estrogen and progesterone, and their receptors play an important role in the development and progression of ovarian carcinoma. Androgen, its receptor and coactivators have also been implicated in these processes. p44/Mep50/WDR77 was identified as a subunit of the methylosome complex and lately characterized as a steroid receptor coactivator that enhances androgen receptor as well as estrogen receptor-mediated transcriptional activity in a ligand-dependent manner. We previously described distinct expression and function of p44 in prostate, testis, and breast cancers. In this report, we examined the expression and function of p44 in ovarian cancer. In contrast to findings in prostate and testicular cancer and similar to breast cancer, p44 shows strong cytoplasmic localization in morphologically normal ovarian surface and fallopian tube epithelia, while nuclear p44 is observed in invasive ovarian carcinoma. We observed that p44 can serve as a coactivator of both androgen receptor (AR and estrogen receptor (ER in ovarian cells. Further, overexpression of nuclear-localized p44 stimulates proliferation and invasion in ovarian cancer cells in the presence of estrogen or androgen. These findings strongly suggest that p44 plays a role in mediating the effects of hormones during ovarian tumorigenesis.

  6. Protein arginine methyltransferase 5 (PRMT5) is a novel coactivator of constitutive androstane receptor (CAR)

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, Yuichiro, E-mail: ykanno@phar.toho-u.ac.jp; Inajima, Jun; Kato, Sayaka; Matsumoto, Maika; Tokumoto, Chikako; Kure, Yuki; Inouye, Yoshio

    2015-03-27

    The constitutive androstane receptor (CAR) plays a key role in the expression of xenobiotic/steroid and drug metabolizing enzymes and their transporters. In this study, we demonstrated that protein arginine methyltransferase 5 (PRMT5) is a novel CAR-interacting protein. Furthermore, the PRMT-dependent induction of a CAR reporter gene, which was independent of methyltransferase activity, was enhanced in the presence of steroid receptor coactivator 1 (SRC1), peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) or DEAD box DNA/RNA helicase DP97. Using tetracycline inducible-hCAR system in HepG2 cells, we showed that knockdown of PRMT5 with small interfering RNA suppressed tetracycline -induced mRNA expression of CYP2B6 but not of CYP2C9 or CYP3A4. PRMT5 enhanced phenobarbital-mediated transactivation of a phenobarbital-responsive enhancer module (PBREM)-driven reporter gene in co-operation with PGC-1α in rat primary hepatocytes. Based on these findings, we suggest PRMT5 to be a gene (or promoter)-selective coactivator of CAR by mediating the formation of complexes between hCAR and appropriate coactivators. - Highlights: • Nuclear receptor CAR interact with PRMT5. • PRMT5 enhances transcriptional activity of CAR. • PRMT5 synergistically enhances transactivity of CAR by the co-expression of SRC-1, DP97 or PGC1α. • PRMT5 is a gene-selective co-activator for hCAR.

  7. The Function of Steroid Receptor Coactivator-1 in Normal Tissues and Cancer

    Directory of Open Access Journals (Sweden)

    Claire A. Walsh, Li Qin, Jean Ching-Yi Tien, Leonie S. Young, Jianming Xu

    2012-01-01

    Full Text Available In 1995, the steroid receptor coactivator-1 (SRC-1 was identified as the first authentic steroid receptor coactivator. Since then, the SRC proteins have remained at the epicenter of coregulator biology, molecular endocrinology and endocrine-related cancer. Cumulative works on SRC-1 have shown that it is primarily a nuclear receptor coregulator and functions to construct highly specific enzymatic protein complexes which can execute efficient and successful transcriptional activation of designated target genes. The versatile nature of SRC-1 enables it to respond to steroid dependent and steroid independent stimulation, allowing it to bind across many families of transcription factors to orchestrate and regulate complex physiological reactions. This review highlights the multiple functions of SRC-1 in the development and maintenance of normal tissue functions as well as its major role in mediating hormone receptor responsiveness. Insights from genetically manipulated mouse models and clinical data suggest SRC-1 is significantly overexpressed in many cancers, in particular, cancers of the reproductive tissues. SRC-1 has been associated with cellular proliferation and tumor growth but its major tumorigenic contributions are promotion and execution of breast cancer metastasis and mediation of resistance to endocrine therapies. The ability of SRC-1 to coordinate multiple signaling pathways makes it an important player in tumor cells' escape of targeted therapy.

  8. Identification of verrucarin a as a potent and selective steroid receptor coactivator-3 small molecule inhibitor.

    Directory of Open Access Journals (Sweden)

    Fei Yan

    Full Text Available Members of the steroid receptor coactivator (SRC family are overexpressed in numerous types of cancers. In particular, steroid receptor coactivator 3 (SRC-3 has been recognized as a critical coactivator associated with tumor initiation, progression, recurrence, metastasis, and chemoresistance where it interacts with multiple nuclear receptors and other transcription factors to enhance their transcriptional activities and facilitate cross-talk between pathways that stimulate cancer progression. Because of its central role as an integrator of growth signaling pathways, development of small molecule inhibitors (SMIs against SRCs have the potential to simultaneously disrupt multiple signal transduction networks and transcription factors involved in tumor progression. Here, high-throughput screening was performed to identify compounds able to inhibit the intrinsic transcriptional activities of the three members of the SRC family. Verrucarin A was identified as a SMI that can selectively promote the degradation of the SRC-3 protein, while affecting SRC-1 and SRC-2 to a lesser extent and having no impact on CARM-1 and p300 protein levels. Verrucarin A was cytotoxic toward multiple types of cancer cells at low nanomolar concentrations, but not toward normal liver cells. Moreover, verrucarin A was able to inhibit expression of the SRC-3 target genes MMP2 and MMP13 and attenuated cancer cell migration. We found that verrucarin A effectively sensitized cancer cells to treatment with other anti-cancer drugs. Binding studies revealed that verrucarin A does not bind directly to SRC-3, suggesting that it inhibits SRC-3 through its interaction with an upstream effector. In conclusion, unlike other SRC SMIs characterized by our laboratory that directly bind to SRCs, verrucarin A is a potent and selective SMI that blocks SRC-3 function through an indirect mechanism.

  9. Development of a novel molecular sensor for imaging estrogen receptor-coactivator protein-protein interactions.

    Directory of Open Access Journals (Sweden)

    Madryn C Lake

    Full Text Available Anti-estrogens, in particular tissue selective anti-estrogens, have been the bedrock of adjuvant therapy for patients with estrogen receptor alpha (ERα positive breast cancer. Though current therapies have greatly enhanced patient prognosis, there continues to be an impetus for the development of improved anti-estrogens. ERα is a nuclear receptor transcription factor which activates gene expression through the recruitment of transcriptional coactivator proteins. The SRC family of coactivators, which includes AIB1, has been shown to be of particular importance for ERα mediated transcription. ERα-AIB1 interactions are indicative of gene expression and are inhibited by anti-estrogen treatment. We have exploited the interaction between ERα and AIB1 as a novel method for imaging ERα activity using a split luciferase molecular sensor. By producing a range of ERα ligand binding domain (ER-LBD and AIB1 nuclear receptor interacting domain (AIB-RID N- and C-terminal firefly luciferase fragment fusion proteins, constructs which exhibited more than a 10-fold increase in luciferase activity with E2 stimulation were identified. The specificity of the E2-stimulated luciferase activity to ERα-AIB1 interaction was validated through Y537S and L539/540A ER-LBD fusion protein mutants. The primed nature of the split luciferase assay allowed changes in ERα activity, with respect to the protein-protein interactions preceding transcription, to be assessed soon after drug treatment. The novel assay split luciferase detailed in this report enabled modulation of ERα activity to be sensitively imaged in vitro and in living subjects and potentially holds much promise for imaging the efficacy of novel ERα specific therapies.

  10. The Role of Steroid Receptor Coactivator-1 in Breat Cancer

    Science.gov (United States)

    2000-06-01

    toxicity In eukaryotic cells. SRC-1 rapidly degrades after cell lysis, to such an extent that the full length cannot be routinely produced In...in breast cancer. The toxicity of the protein in tissue culture cells In which we attempted to overexpress the full- length and dominant -negative... Mifepristone (RU486): a review. Fertil Steril, 68, 967-976. McKenna, N.J., Lanz, R.B. and O’Malley, B.W. (1999) Nuclear receptor coregulators: cellular

  11. Characterization of ASC-2 as an antiatherogenic transcriptional coactivator of liver X receptors in macrophages.

    Science.gov (United States)

    Kim, Geun Hyang; Park, Keunhee; Yeom, Seon-Yong; Lee, Kyung Jin; Kim, Gukhan; Ko, Jesang; Rhee, Dong-Kwon; Kim, Young Hoon; Lee, Hye Kyung; Kim, Hae Won; Oh, Goo Taeg; Lee, Ki-Up; Lee, Jae W; Kim, Seung-Whan

    2009-07-01

    Activating signal cointegrator-2 (ASC-2) functions as a transcriptional coactivator of many nuclear receptors and also plays important roles in the physiology of the liver and pancreas by interacting with liver X receptors (LXRs), which antagonize the development of atherosclerosis. This study was undertaken to establish the specific function of ASC-2 in macrophages and atherogenesis. Intriguingly, ASC-2 was more highly expressed in macrophages than in the liver and pancreas. To inhibit LXR-specific activity of ASC-2, we used DN2, which contains the C-terminal LXXLL motif of ASC-2 and thereby acts as an LXR-specific, dominant-negative mutant of ASC-2. In DN2-overexpressing transgenic macrophages, cellular cholesterol content was higher and cholesterol efflux lower than in control macrophages. DN2 reduced LXR ligand-dependent increases in the levels of ABCA1, ABCG1, and apolipoprotein E (apoE) transcripts as well as the activity of luciferase reporters driven by the LXR response elements (LXREs) of ABCA1, ABCG1, and apoE genes. These inhibitory effects of DN2 were reversed by overexpression of ASC-2. Chromatin immunoprecipitation analysis demonstrated that ASC-2 was recruited to the LXREs of the ABCA1, ABCG1, and apoE genes in a ligand-dependent manner and that DN2 interfered with the recruitment of ASC-2 to these LXREs. Furthermore, low-density lipoprotein receptor (LDLR)-null mice receiving bone marrow transplantation from DN2-transgenic mice showed accelerated atherogenesis when administered a high-fat diet. Taken together, these results indicate that suppression of the LXR-specific activity of ASC-2 results in both defective cholesterol metabolism in macrophages and accelerated atherogenesis, suggesting that ASC-2 is an antiatherogenic coactivator of LXRs in macrophages.

  12. Examination of Ligand-Dependent Coactivator Recruitment by Peroxisome Proliferator-Activated Receptor-alpha (PPARalpha).

    Science.gov (United States)

    Tien, Eric S; Hannon, Daniel B; Thompson, Jerry T; Vanden Heuvel, John P

    2006-01-01

    The ligand-dependent recruitment of coactivators to peroxisome proliferator-activated receptor-alpha (PPARalpha) was examined. PPAR-binding protein (PBP), PPARgamma coactivator-1alpha (PGC-1alpha), steroid receptor coactivator-1 (SRC-1), and CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2) affected PPARalpha activity in the presence of Wy-14,643. The effects on PPARalpha activity in light of increased or decreased expression of these coactivators were qualitatively different depending on the ligand examined. Diminished expression of PGC-1alpha, SRC-1, or PBP by RNAi plasmids affected natural or synthetic agonist activity whereas only Wy-14,643 was affected by decreased PGC-1alpha. The interaction of PPARalpha with an LXXLL-containing peptide library showed ligand-specific patterns, indicative of differences in conformational change. The association of coactivators to PPARalpha occurs predominantly via the carboxyl-terminus and mutating (456)LHPLL to (456)LHPAA resulted in a dominant-negative construct. This research confirms that coactivator recruitment to PPARalpha is ligand-dependent and that selective receptor modulators (SRMs) of this important protein are likely.

  13. Examination of Ligand-Dependent Coactivator Recruitment by Peroxisome Proliferator-Activated Receptor-α (PPARα)

    Science.gov (United States)

    Tien, Eric S.; Hannon, Daniel B.; Thompson, Jerry T.; Vanden Heuvel, John P.

    2006-01-01

    The ligand-dependent recruitment of coactivators to peroxisome proliferator-activated receptor-α (PPARα) was examined. PPAR-binding protein (PBP), PPARγ coactivator-1α (PGC-1α), steroid receptor coactivator-1 (SRC-1), and CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2) affected PPARα activity in the presence of Wy-14,643. The effects on PPARα activity in light of increased or decreased expression of these coactivators were qualitatively different depending on the ligand examined. Diminished expression of PGC-1α, SRC-1, or PBP by RNAi plasmids affected natural or synthetic agonist activity whereas only Wy-14,643 was affected by decreased PGC-1α. The interaction of PPARα with an LXXLL-containing peptide library showed ligand-specific patterns, indicative of differences in conformational change. The association of coactivators to PPARα occurs predominantly via the carboxyl-terminus and mutating 456LHPLL to 456LHPAA resulted in a dominant-negative construct. This research confirms that coactivator recruitment to PPARα is ligand-dependent and that selective receptor modulators (SRMs) of this important protein are likely. PMID:17259669

  14. The transcriptional coactivator DRIP/mediator complex is involved in vitamin D receptor function and regulates keratinocyte proliferation and differentiation.

    Science.gov (United States)

    Oda, Yuko; Chalkley, Robert J; Burlingame, Alma L; Bikle, Daniel D

    2010-10-01

    Mediator is a multisubunit coactivator complex that facilitates transcription of nuclear receptors. We investigated the role of the mediator complex as a coactivator for vitamin D receptor (VDR) in keratinocytes. Using VDR affinity beads, the vitamin D receptor interacting protein (DRIP)/mediator complex was purified from primary keratinocytes, and its subunit composition was determined by mass spectrometry. The complex included core subunits, such as DRIP205/MED1 (MED1), that directly binds to VDR. Additional subunits were identified that are components of the RNA polymerase II complex. The functions of different mediator components were investigated by silencing its subunits. The core subunit MED1 facilitates VDR activity and regulating keratinocyte proliferation and differentiation. A newly described subunit MED21 also has a role in promoting keratinocyte proliferation and differentiation, whereas MED10 has an inhibitory role. Blocking MED1/MED21 expression caused hyperproliferation of keratinocytes, accompanied by increases in mRNA expression of the cell cycle regulator cyclin D1 and/or glioma-associated oncogene homolog. Blocking MED1 or MED21 expression also resulted in defects in calcium-induced keratinocyte differentiation, as indicated by decreased expression of differentiation markers and decreased translocation of E-cadherin to the membrane. These results show that keratinocytes use the transcriptional coactivator mediator to regulate VDR functions and control keratinocyte proliferation and differentiation.

  15. Mitochondrial fusion is increased by the nuclear coactivator PGC-1beta.

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    Marc Liesa

    Full Text Available BACKGROUND: There is no evidence to date on whether transcriptional regulators are able to shift the balance between mitochondrial fusion and fission events through selective control of gene expression. METHODOLOGY/PRINCIPAL FINDINGS: Here, we demonstrate that reduced mitochondrial size observed in knock-out mice for the transcriptional regulator PGC-1beta is associated with a selective reduction in Mitofusin 2 (Mfn2 expression, a mitochondrial fusion protein. This decrease in Mfn2 is specific since expression of the remaining components of mitochondrial fusion and fission machinery were not affected. Furthermore, PGC-1beta increases mitochondrial fusion and elongates mitochondrial tubules. This PGC-1beta-induced elongation specifically requires Mfn2 as this process is absent in Mfn2-ablated cells. Finally, we show that PGC-1beta increases Mfn2 promoter activity and transcription by coactivating the nuclear receptor Estrogen Related Receptor alpha (ERRalpha. CONCLUSIONS/SIGNIFICANCE: Taken together, our data reveal a novel mechanism by which mammalian cells control mitochondrial fusion. In addition, we describe a novel role of PGC-1beta in mitochondrial physiology, namely the control of mitochondrial fusion mainly through Mfn2.

  16. Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Teilum, Kaare; Poulsen, Flemming M

    2010-01-01

    Native molten globules are the most folded kind of intrinsically disordered proteins. Little is known about the mechanism by which native molten globules bind to their cognate ligands to form fully folded complexes. The nuclear coactivator binding domain (NCBD) of CREB binding protein is particul...

  17. Dynamic distribution of nuclear coactivator 4 during mitosis: association with mitotic apparatus and midbodies.

    Directory of Open Access Journals (Sweden)

    Alexandra Kollara

    Full Text Available The cytoplasmic localization of Nuclear Receptor Coactivator 4 (NcoA4, also referred to as androgen receptor associated protein 70 (ARA70, indicates it may possess activities in addition to its role within the nucleus as a transcriptional enhancer. Towards identifying novel functions of NcoA4, we performed an in silico analysis of its amino acid sequence to identify potential functional domains and related proteins, and examined its subcellular distribution throughout the cell cycle. NcoA4 has no known or predicted functional or structural domains with the exception of an LxxLL and FxxLF nuclear receptor interaction motif and an N-terminal putative coiled-coil domain. Phylogenetic analysis indicated that NcoA4 has no paralogs and that a region referred to as ARA70-I family domain, located within the N-terminus and overlapping with the coiled-coil domain, is evolutionarily conserved in metazoans ranging from cnidarians to mammals. An adjacent conserved region, designated ARA70-II family domain, with no significant sequence similarity to the ARA70-I domain, is restricted to vertebrates. We demonstrate NcoA4 co-localizes with microtubules and microtubule organizing centers during prophase. Strong NcoA4 accumulation at the centrosomes was detected during interphase and telophase, with decreased levels at metaphase and anaphase. NcoA4 co-localized with tubulin and acetylated tubulin to the mitotic spindles during metaphase and anaphase, and to midbodies during telophase. Consistent with these observations, we demonstrated an interaction between NcoA4 and α-tubulin. Co-localization was not observed with microfilaments. These findings indicate a dynamic distribution of NcoA4 with components of the mitotic apparatus that is consistent with a potential non-transcriptional regulatory function(s during cell division, which may be evolutionarily conserved.

  18. Steroid receptor coactivator 1 deficiency increases MMTV-neu mediated tumor latency and differentiation specific gene expression, decreases metastasis, and inhibits response to PPAR ligands

    Directory of Open Access Journals (Sweden)

    Crowe David L

    2010-11-01

    Full Text Available Abstract Background The peroxisome proliferator activated receptor (PPAR subgroup of the nuclear hormone receptor superfamily is activated by a variety of natural and synthetic ligands. PPARs can heterodimerize with retinoid X receptors, which have homology to other members of the nuclear receptor superfamily. Ligand binding to PPAR/RXRs results in recruitment of transcriptional coactivator proteins such as steroid receptor coactivator 1 (SRC-1 and CREB binding protein (CBP. Both SRC-1 and CBP are histone acetyltransferases, which by modifying nucleosomal histones, produce more open chromatin structure and increase transcriptional activity. Nuclear hormone receptors can recruit limiting amounts of coactivators from other transcription factor binding sites such as AP-1, thereby inhibiting the activity of AP-1 target genes. PPAR and RXR ligands have been used in experimental breast cancer therapy. The role of coactivator expression in mammary tumorigenesis and response to drug therapy has been the subject of recent studies. Methods We examined the effects of loss of SRC-1 on MMTV-neu mediated mammary tumorigenesis. Results SRC-1 null mutation in mammary tumor prone mice increased the tumor latency period, reduced tumor proliferation index and metastasis, inhibited response to PPAR and RXR ligands, and induced genes involved in mammary gland differentiation. We also examined human breast cancer cell lines overexpressing SRC-1 or CBP. Coactivator overexpression increased cellular proliferation with resistance to PPAR and RXR ligands and remodeled chromatin of the proximal epidermal growth factor receptor promoter. Conclusions These results indicate that histone acetyltransferases play key roles in mammary tumorigenesis and response to anti-proliferative therapies.

  19. Distinct expression profiles of transcriptional coactivators for thyroid hormone receptors during Xenopus laevis metamorphosis

    Institute of Scientific and Technical Information of China (English)

    BINDU D PAUL; YUN-BO SHI

    2003-01-01

    The biological effects of thyroid hormone(T3)are mediated by the thyroid hormone receptor(TR).Amphibian metamorphosis is one of the most dramatic processes that are dependent on T3.T3 regulates a series of orchestrated developmental changes,which ultimately result in the conversion of an aquatic herbivorous tadpole to a terrestrial carnivorous frog.T3 is presumed to bind to TRs,which in turn recruit coactivators,leading to gene activation.The best-studied coactivators belong to the p 160 or SRC family.Members of this family include SRC 1/NCoA- 1,SRC2/TIF2/GRIP 1,and SRC3/pCIP/ACTR/AIB- 1/RAC-3/TRAM- 1.These SRCs interact directly with liganded TR and function as adapter molecules to recruit other coactivators such as p300/CBP.Here,we studied the expression patterns of these coactivators during various stages of development.Amongst the coactivators cloned in Xenopus laevis,SRC3 was found to be dramatically upregulated during natural and T3-induced metamorphosis,and SRC2 and p300 are expressed throughout postembryonic development with little change in their expression levels.These results support the view that these coactivators participate in gene regulation by TR during metamorphosis.

  20. Chromatin remodeling regulated by steroid and nuclear receptors

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    Coactivators and corepressors regulate transcription by controlling interactions between sequence-specific transcription factors,the basal transcriptional machinery and the chromatin environment,This review consider the access of nuclear and steroid receptors to chromatin,their use of corepressors and coactivators to modify chromatin structure and the implications for transcriptional control.The assembly of specific nucleoprotein architectures and targeted histone modification emerge as central controlling elements for gene expression.

  1. Evidence of an association between genetic variation of the coactivator PGC-1beta and obesity

    DEFF Research Database (Denmark)

    Andersen, G; Wegner, L; Yanagisawa, K

    2005-01-01

    Peroxisome proliferator activated receptor-gamma coactivator-1beta (PGC-1beta) is a recently identified homologue of the tissue specific coactivator PGC-1alpha, a coactivator of transcription factors such as the peroxisome proliferators activated receptors and nuclear respiratory factors. PGC-1......alpha is involved in adipogenesis, mitochondrial biogenesis, fatty acid beta oxidation, and hepatic gluconeogenesis....

  2. Energy-sensing Factors Coactivator Peroxisome Proliferator-activated Receptor gamma Coactivator 1-alpha (PGC-1 alpha) and AMP-activated Protein Kinase Control Expression of Inflammatory Mediators in Liver INDUCTION OF INTERLEUKIN 1 RECEPTOR ANTAGONIST

    NARCIS (Netherlands)

    Buler, M.; Aatsinki, S.M.; Skoumal, R.; Komka, Z.; Toth, M.; Kerkela, R.; Georgiadi, A.; Kersten, A.H.; Hakkola, J.

    2012-01-01

    Obesity and insulin resistance are associated with chronic, low grade inflammation. Moreover, regulation of energy metabolism and immunity are highly integrated. We hypothesized that energy-sensitive coactivator peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) and A

  3. The Orphan Nuclear Receptor TR4 Is a Vitamin A-activated Nuclear Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X. Edward; Suino-Powell, Kelly M.; Xu, Yong; Chan, Cee-Wah; Tanabe, Osamu; Kruse, Schoen W.; Reynolds, Ross; Engel, James Douglas; Xu, H. Eric (Michigan-Med); (Van Andel)

    2015-11-30

    Testicular receptors 2 and 4 (TR2/4) constitute a subgroup of orphan nuclear receptors that play important roles in spermatogenesis, lipid and lipoprotein regulation, and the development of the central nervous system. Currently, little is known about the structural features and the ligand regulation of these receptors. Here we report the crystal structure of the ligand-free TR4 ligand binding domain, which reveals an autorepressed conformation. The ligand binding pocket of TR4 is filled by the C-terminal half of helix 10, and the cofactor binding site is occupied by the AF-2 helix, thus preventing ligand-independent activation of the receptor. However, TR4 exhibits constitutive transcriptional activity on multiple promoters, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, or ligand binding substantially reduce the transcriptional activity of this receptor. Importantly, both retinol and retinoic acid are able to promote TR4 to recruit coactivators and to activate a TR4-regulated reporter. These findings demonstrate that TR4 is a ligand-regulated nuclear receptor and suggest that retinoids might have a much wider regulatory role via activation of orphan receptors such as TR4.

  4. The orphan nuclear receptor TR4 is a vitamin A-activated nuclear receptor.

    Science.gov (United States)

    Zhou, X Edward; Suino-Powell, Kelly M; Xu, Yong; Chan, Cee-Wah; Tanabe, Osamu; Kruse, Schoen W; Reynolds, Ross; Engel, James Douglas; Xu, H Eric

    2011-01-28

    Testicular receptors 2 and 4 (TR2/4) constitute a subgroup of orphan nuclear receptors that play important roles in spermatogenesis, lipid and lipoprotein regulation, and the development of the central nervous system. Currently, little is known about the structural features and the ligand regulation of these receptors. Here we report the crystal structure of the ligand-free TR4 ligand binding domain, which reveals an autorepressed conformation. The ligand binding pocket of TR4 is filled by the C-terminal half of helix 10, and the cofactor binding site is occupied by the AF-2 helix, thus preventing ligand-independent activation of the receptor. However, TR4 exhibits constitutive transcriptional activity on multiple promoters, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, or ligand binding substantially reduce the transcriptional activity of this receptor. Importantly, both retinol and retinoic acid are able to promote TR4 to recruit coactivators and to activate a TR4-regulated reporter. These findings demonstrate that TR4 is a ligand-regulated nuclear receptor and suggest that retinoids might have a much wider regulatory role via activation of orphan receptors such as TR4.

  5. The p160/steroid receptor coactivator family: potent arbiters of uterine physiology and dysfunction.

    Science.gov (United States)

    Szwarc, Maria M; Kommagani, Ramakrishna; Lessey, Bruce A; Lydon, John P

    2014-11-01

    The p160/steroid receptor coactivator (SRC) family comprises three pleiotropic coregulators (SRC-1, SRC-2, and SRC-3; otherwise known as NCOA1, NCOA2, and NCOA3, respectively), which modulate a wide spectrum of physiological responses and clinicopathologies. Such pleiotropy is achieved through their inherent structural complexity, which allows this coregulator class to control both nuclear receptor and non-nuclear receptor signaling. As observed in other physiologic systems, members of the SRC family have recently been shown to play pivotal roles in uterine biology and pathobiology. In the murine uterus, SRC-1 is required to launch a full steroid hormone response, without which endometrial decidualization is markedly attenuated. From "dovetailing" clinical and mouse studies, an isoform of SRC-1 was recently identified which promotes endometriosis by reprogramming endometrial cells to evade apoptosis and to colonize as endometriotic lesions within the peritoneal cavity. The endometrium fails to decidualize without SRC-2, which accounts for the infertility phenotype exhibited by mice devoid of this coregulator. In related studies on human endometrial stromal cells, SRC-2 was shown to act as a molecular "pacemaker" of the glycolytic flux. This finding is significant because acceleration of the glycolytic flux provides the necessary bioenergy and biomolecules for endometrial stromal cells to switch from quiescence to a proliferative phenotype, a critical underpinning in the decidual progression program. Although studies on uterine SRC-3 function are in their early stages, clinical studies provide tantalizing support for the proposal that SRC-3 is causally linked to endometrial hyperplasia as well as with endometrial pathologies in patients diagnosed with polycystic ovary syndrome. This proposal is now driving the development and application of innovative technologies, particularly in the mouse, to further understand the functional role of this elusive uterine

  6. Photoperiodic regulation of androgen receptor and steroid receptor coactivator-1 in Siberian hamster brain.

    Science.gov (United States)

    Tetel, Marc J; Ungar, Todd C; Hassan, Brett; Bittman, Eric L

    2004-11-24

    Seasonal changes in the neuroendocrine actions of gonadal steroid hormones are triggered by fluctuations in daylength. The mechanisms responsible for photoperiodic influences upon the feedback and behavioral effects of testosterone in Siberian hamsters are poorly understood. We hypothesized that daylength regulates the expression of androgen receptor (AR) and/or steroid receptor coactivator-1 (SRC-1) in specific forebrain regions. Hamsters were castrated and implanted with either oil-filled capsules or low doses of testosterone; half of the animals remained in 16L/8D and the rest were kept in 10L/14D for the ensuing 70 days. The number of AR-immunoreactive (AR-ir) cells was regulated by testosterone in medial amygdala and caudal arcuate, and by photoperiod in the medial preoptic nucleus and the posterodorsal medial amygdala. A significant interaction between photoperiod and androgen treatment was found in medial preoptic nucleus and posterodorsal medial amygdala. The molecular weight and distribution of SRC-1 were similar to reports in other rodent species, and short days reduced the number of SRC-1-ir cells in posteromedial bed nucleus of the stria terminalis (BNST) and posterodorsal medial amygdala. A significant interaction between androgen treatment and daylength in regulation of SRC-1-ir was found in anterior medial amygdala. The present results indicate that daylength-induced fluctuations in SRC-1 and AR expression may contribute to seasonally changing effects of testosterone.

  7. Pax6 represses androgen receptor-mediated transactivation by inhibiting recruitment of the coactivator SPBP.

    Directory of Open Access Journals (Sweden)

    Julianne Elvenes

    Full Text Available The androgen receptor (AR has a central role in development and maintenance of the male reproductive system and in the etiology of prostate cancer. The transcription factor Pax6 has recently been reported to act as a repressor of AR and to be hypermethylated in prostate cancer cells. SPBP is a transcriptional regulator that previously has been shown to enhance the activity of Pax6. In this study we have identified SPBP to act as a transcriptional coactivator of AR. We also show that Pax6 inhibits SPBP-mediated enhancement of AR activity on the AR target gene probasin promoter, a repression that was partly reversed by increased expression of SPBP. Enhanced expression of Pax6 reduced the amount of SPBP associated with the probasin promoter when assayed by ChIP in HeLa cells. We mapped the interaction between both AR and SPBP, and AR and Pax6 to the DNA-binding domains of the involved proteins. Further binding studies revealed that Pax6 and SPBP compete for binding to AR. These results suggest that Pax6 represses AR activity by displacing and/or inhibiting recruitment of coactivators to AR target promoters. Understanding the mechanism for inhibition of AR coactivators can give rise to molecular targeted drugs for treatment of prostate cancer.

  8. Regulation of the transcriptional coactivator FHL2 licenses activation of the androgen receptor in castrate-resistant prostate cancer.

    Science.gov (United States)

    McGrath, Meagan J; Binge, Lauren C; Sriratana, Absorn; Wang, Hong; Robinson, Paul A; Pook, David; Fedele, Clare G; Brown, Susan; Dyson, Jennifer M; Cottle, Denny L; Cowling, Belinda S; Niranjan, Birunthi; Risbridger, Gail P; Mitchell, Christina A

    2013-08-15

    It is now clear that progression from localized prostate cancer to incurable castrate-resistant prostate cancer (CRPC) is driven by continued androgen receptor (AR), signaling independently of androgen. Thus, there remains a strong rationale to suppress AR activity as the single most important therapeutic goal in CRPC treatment. Although the expression of ligand-independent AR splice variants confers resistance to AR-targeted therapy and progression to lethal castrate-resistant cancer, the molecular regulators of AR activity in CRPC remain unclear, in particular those pathways that potentiate the function of mutant AR in CRPC. Here, we identify FHL2 as a novel coactivator of ligand-independent AR variants that are important in CRPC. We show that the nuclear localization of FHL2 and coactivation of the AR is driven by calpain cleavage of the cytoskeletal protein filamin, a pathway that shows differential activation in prostate epithelial versus prostate cancer cell lines. We further identify a novel FHL2-AR-filamin transcription complex, revealing how deregulation of this axis promotes the constitutive, ligand-independent activation of AR variants, which are present in CRPC. Critically, the calpain-cleaved filamin fragment and FHL2 are present in the nucleus only in CRPC and not benign prostate tissue or localized prostate cancer. Thus, our work provides mechanistic insight into the enhanced AR activation, most notably of the recently identified AR variants, including AR-V7 that drives CRPC progression. Furthermore, our results identify the first disease-specific mechanism for deregulation of FHL2 nuclear localization during cancer progression. These results offer general import beyond prostate cancer, given that nuclear FHL2 is characteristic of other human cancers where oncogenic transcription factors that drive disease are activated like the AR in prostate cancer.

  9. Involvement of Steroid Receptor Coactivators/Ubiquitin Pathway Enzymes in Mammary Gland Tumorigenesis

    Science.gov (United States)

    2005-06-01

    PRINCIPAL INVESTIGATOR: Xiuhua Gao, M.D., Ph.D. CONTRACTING ORGANIZATION: Baylor College of Medicine Houston, TX 77030 REPORT DATE: June 2005 TYPE OF REPORT...Summary 13 May 2002 - 12 May 2005 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Involvement of Steroid Receptor Coactivators/Ubiquitin Pathway 5b...Usell tc localization of MUcle ~s. Eý a, Eý Ca exaressiorn Crofile; E-p groffle; W1~’, API staining for nUcleUs. E6-AP DAMP -HI +E Figure 2: Effect of

  10. TBP binding-induced folding of the glucocorticoid receptor AF1 domain facilitates its interaction with steroid receptor coactivator-1.

    Directory of Open Access Journals (Sweden)

    Shagufta H Khan

    Full Text Available The precise mechanism by which glucocorticoid receptor (GR regulates the transcription of its target genes is largely unknown. This is, in part, due to the lack of structural and functional information about GR's N-terminal activation function domain, AF1. Like many steroid hormone receptors (SHRs, the GR AF1 exists in an intrinsically disordered (ID conformation or an ensemble of conformers that collectively appears to be unstructured. The GR AF1 is known to recruit several coregulatory proteins, including those from the basal transcriptional machinery, e.g., TATA box binding protein (TBP that forms the basis for the multiprotein transcription initiation complex. However, the precise mechanism of this process is unknown. We have earlier shown that conditional folding of the GR AF1 is the key for its interactions with critical coactivator proteins. We hypothesize that binding of TBP to AF1 results in the structural rearrangement of the ID AF1 domain such that its surfaces become easily accessible for interaction with other coactivators. To test this hypothesis, we determined whether TBP binding-induced structure formation in the GR AF1 facilitates its interaction with steroid receptor coactivator-1 (SRC-1, a critical coactivator that is important for GR-mediated transcriptional activity. Our data show that stoichiometric binding of TBP induces significantly higher helical content at the expense of random coil configuration in the GR AF1. Further, we found that this induced AF1 conformation facilitates its interaction with SRC-1, and subsequent AF1-mediated transcriptional activity. Our results may provide a potential mechanism through which GR and by large other SHRs may regulate the expression of the GR-target genes.

  11. Novel CARM1-Interacting Protein, DZIP3, Is a Transcriptional Coactivator of Estrogen Receptor-α.

    Science.gov (United States)

    Purcell, Daniel J; Chauhan, Swati; Jimenez-Stinson, Diane; Elliott, Kathleen R; Tsewang, Tenzin D; Lee, Young-Ho; Marples, Brian; Lee, David Y

    2015-12-01

    Coactivator-associated arginine methyltransferase 1 (CARM1) is known to promote estrogen receptor (ER)α-mediated transcription in breast cancer cells. To further characterize the regulation of ERα-mediated transcription by CARM1, we screened CARM1-interacting proteins by yeast two-hybrid. Here, we have identified an E3 ubiquitin ligase, DAZ (deleted in azoospermia)-interacting protein 3 (DZIP3), as a novel CARM1-binding protein. DZIP3-dependent ubiquitination of histone H2A has been associated with repression of transcription. However, ERα reporter gene assays demonstrated that DZIP3 enhanced ERα-mediated transcription and cooperated synergistically with CARM1. Interaction with CARM1 was observed with the E3 ligase RING domain of DZIP3. The methyltransferase activity of CARM1 partially contributed to the synergy with DZIP3 for transcription activation, but the E3 ubiquitin ligase activity of DZIP3 was dispensable. DZIP3 also interacted with the C-terminal activation domain 2 of glucocorticoid receptor-interacting protein 1 (GRIP1) and enhanced the interaction between GRIP1 and CARM1. Depletion of DZIP3 by small interfering RNA in MCF7 cells reduced estradiol-induced gene expression of ERα target genes, GREB1 and pS2, and DZIP3 was recruited to the estrogen response elements of the same ERα target genes. These results indicate that DZIP3 is a novel coactivator of ERα target gene expression.

  12. Ash2 acts as an ecdysone receptor coactivator by stabilizing the histone methyltransferase Trr.

    Science.gov (United States)

    Carbonell, Albert; Mazo, Alexander; Serras, Florenci; Corominas, Montserrat

    2013-02-01

    The molting hormone ecdysone triggers chromatin changes via histone modifications that are important for gene regulation. On hormone activation, the ecdysone receptor (EcR) binds to the SET domain-containing histone H3 methyltransferase trithorax-related protein (Trr). Methylation of histone H3 at lysine 4 (H3K4me), which is associated with transcriptional activation, requires several cofactors, including Ash2. We find that ash2 mutants have severe defects in pupariation and metamorphosis due to a lack of activation of ecdysone-responsive genes. This transcriptional defect is caused by the absence of the H3K4me3 marks set by Trr in these genes. We present evidence that Ash2 interacts with Trr and is required for its stabilization. Thus we propose that Ash2 functions together with Trr as an ecdysone receptor coactivator.

  13. Ligand-specific allosteric regulation of coactivator functions of androgen receptor in prostate cancer cells

    OpenAIRE

    Baek, Sung Hee; Ohgi, Kenneth A.; Nelson, Charles A.; Welsbie, Derek; Chen, Charlie; Charles L Sawyers; Rose, David W.; Rosenfeld, Michael G.

    2006-01-01

    The androgen receptor not only mediates prostate development but also serves as a key regulator of primary prostatic cancer growth. Although initially responsive to selective androgen receptor modulators (SARMs), which cause recruitment of the nuclear receptor–corepressor (N-CoR) complex, resistance invariably occurs, perhaps in response to inflammatory signals. Here we report that dismissal of nuclear receptor–corepressor complexes by specific signals or androgen receptor overexpression resu...

  14. Downstream signaling mechanism of the C-terminal activation domain of transcriptional coactivator CoCoA

    OpenAIRE

    Kim, Jeong Hoon; Yang, Catherine K.; Stallcup, Michael R

    2006-01-01

    The coiled-coil coactivator (CoCoA) is a transcriptional coactivator for nuclear receptors and enhances nuclear receptor function by the interaction with the bHLH-PAS domain (AD3) of p160 coactivators. The C-terminal activation domain (AD) of CoCoA possesses strong transactivation activity and is required for the coactivator function of CoCoA with nuclear receptors. To understand how CoCoA AD transmits its activating signal to the transcription machinery, we defined specific subregions, amino...

  15. Structural and Functional Impacts of ER Coactivator Sequential Recruitment.

    Science.gov (United States)

    Yi, Ping; Wang, Zhao; Feng, Qin; Chou, Chao-Kai; Pintilie, Grigore D; Shen, Hong; Foulds, Charles E; Fan, Guizhen; Serysheva, Irina; Ludtke, Steven J; Schmid, Michael F; Hung, Mien-Chie; Chiu, Wah; O'Malley, Bert W

    2017-09-07

    Nuclear receptors recruit multiple coactivators sequentially to activate transcription. This "ordered" recruitment allows different coactivator activities to engage the nuclear receptor complex at different steps of transcription. Estrogen receptor (ER) recruits steroid receptor coactivator-3 (SRC-3) primary coactivator and secondary coactivators, p300/CBP and CARM1. CARM1 recruitment lags behind the binding of SRC-3 and p300 to ER. Combining cryo-electron microscopy (cryo-EM) structure analysis and biochemical approaches, we demonstrate that there is a close crosstalk between early- and late-recruited coactivators. The sequential recruitment of CARM1 not only adds a protein arginine methyltransferase activity to the ER-coactivator complex, it also alters the structural organization of the pre-existing ERE/ERα/SRC-3/p300 complex. It induces a p300 conformational change and significantly increases p300 HAT activity on histone H3K18 residues, which, in turn, promotes CARM1 methylation activity on H3R17 residues to enhance transcriptional activity. This study reveals a structural role for a coactivator sequential recruitment and biochemical process in ER-mediated transcription. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Coactivators in PPAR-Regulated Gene Expression

    Directory of Open Access Journals (Sweden)

    Navin Viswakarma

    2010-01-01

    Full Text Available Peroxisome proliferator-activated receptor (PPARα, β (also known as δ, and γ function as sensors for fatty acids and fatty acid derivatives and control important metabolic pathways involved in the maintenance of energy balance. PPARs also regulate other diverse biological processes such as development, differentiation, inflammation, and neoplasia. In the nucleus, PPARs exist as heterodimers with retinoid X receptor-α bound to DNA with corepressor molecules. Upon ligand activation, PPARs undergo conformational changes that facilitate the dissociation of corepressor molecules and invoke a spatiotemporally orchestrated recruitment of transcription cofactors including coactivators and coactivator-associated proteins. While a given nuclear receptor regulates the expression of a prescribed set of target genes, coactivators are likely to influence the functioning of many regulators and thus affect the transcription of many genes. Evidence suggests that some of the coactivators such as PPAR-binding protein (PBP/PPARBP/thyroid hormone receptor-associated protein 220 (TRAP220/mediator complex subunit 1 (MED1 may exert a broader influence on the functions of several nuclear receptors and their target genes. Investigations into the role of coactivators in the function of PPARs should strengthen our understanding of the complexities of metabolic diseases associated with energy metabolism.

  17. Meeting report: nuclear receptors

    DEFF Research Database (Denmark)

    Tuckermann, Jan; Bourguet, William; Mandrup, Susanne

    2010-01-01

    The biannual European Molecular Biology Organization (EMBO) conference on nuclear receptors was organized by Beatrice Desvergne and Laszlo Nagy and took place in Cavtat near Dubrovnik on the Adriatic coast of Croatia September 25-29, 2009. The meeting brought together researchers from all over...

  18. The association between nuclear receptors and ocular diseases.

    Science.gov (United States)

    Liu, Ke; Zou, Chang; Qin, Bo

    2017-02-07

    Nuclear hormone receptors (NRs) are one of the most abundant transcription factors in the human cells. They regulate expression of genes via interactions with corresponding ligands, co-activators, and co-repressors. These molecular pathways play important roles in the development, cell differentiation, and physiologic and metabolic processes. Increasingly, targeting nuclear receptors is becoming a promising strategy for new drug development. The aim of this review is to discuss the association between nuclear receptors and eye development, and expand their role in various ocular diseases such as keratitis, cataract, glaucoma, uveitis, retinopathy, and ophthalmic tumors. Recent studies in this area are highlighted as well as future research directions and potential clinical applications. Finally, various strategies will be elucidated to inspire more targeted therapies for ocular diseases through the use of nuclear receptors.

  19. The Role of Nuclear Receptor Coactivators in Recurrent Prostate Cancer

    Science.gov (United States)

    2006-02-01

    10, 1527–1535 35. Newmark, J. R., Hardy, D. O., Tonb , D. C., Carter, B. S., Epstein, J. I., Isaacs, W. B., Brown, T. R., and Barrack, E. R. (1992...J.R., Hardy, D.O., Tonb , D.C., Carter, B.S., Epstein, J.I., 42293–42301. Isaacs, W.B., Brown, T.R., and Barrack, E.R. (1992). Androgen recep- tor gene...Mohler, J. L., French, F. S., and Wilson, E. M. (2001) Cancer Res. 61, 4315–4319 43. Newmark, J. R., Hardy, D. O., Tonb , D. C., Carter, B. S

  20. SIRT1 is a Direct Coactivator of Thyroid Hormone Receptor β1 with Gene-Specific Actions

    Science.gov (United States)

    Suh, Ji Ho; Sieglaff, Douglas H.; Zhang, Aijun; Xia, Xuefeng; Cvoro, Aleksandra; Winnier, Glenn E.; Webb, Paul

    2013-01-01

    Sirtuin 1 (SIRT1) NAD+-dependent deacetylase regulates energy metabolism by modulating expression of genes involved in gluconeogenesis and other liver fasting responses. While many effects of SIRT1 on gene expression are mediated by deacetylation and activation of peroxisome proliferator activated receptor coactivator α (PGC-1α), SIRT1 also binds directly to DNA bound transcription factors, including nuclear receptors (NRs), to modulate their activity. Since thyroid hormone receptor β1 (TRβ1) regulates several SIRT1 target genes in liver and interacts with PGC-1α, we hypothesized that SIRT1 may influence TRβ1. Here, we confirm that SIRT1 cooperates with PGC-1α to enhance response to triiodothyronine, T3. We also find, however, that SIRT1 stimulates TRβ1 activity in a manner that is independent of PGC-1α but requires SIRT1 deacetylase activity. SIRT1 interacts with TRβ1 in vitro, promotes TRβ1 deacetylation in the presence of T3 and enhances ubiquitin-dependent TRβ1 turnover; a common response of NRs to activating ligands. More surprisingly, SIRT1 knockdown only strongly inhibits T3 response of a subset of TRβ1 target genes, including glucose 6 phosphatase (G-6-Pc), and this is associated with blockade of TRβ1 binding to the G-6-Pc promoter. Drugs that target the SIRT1 pathway, resveratrol and nicotinamide, modulate T3 response at dual TRβ1/SIRT1 target genes. We propose that SIRT1 is a gene-specific TRβ1 co-regulator and TRβ1/SIRT1 interactions could play important roles in regulation of liver metabolic response. Our results open possibilities for modulation of subsets of TR target genes with drugs that influence the SIRT1 pathway. PMID:23922917

  1. Androgen Receptor Coactivator ARID4B Is Required for the Function of Sertoli Cells in Spermatogenesis.

    Science.gov (United States)

    Wu, Ray-Chang; Zeng, Yang; Pan, I-Wen; Wu, Mei-Yi

    2015-09-01

    Defects in spermatogenesis, a process that produces spermatozoa inside seminiferous tubules of the testis, result in male infertility. Spermatogenic progression is highly dependent on a microenvironment provided by Sertoli cells, the only somatic cells and epithelium of seminiferous tubules. However, genes that regulate such an important activity of Sertoli cells are poorly understood. Here, we found that AT-rich interactive domain 4B (ARID4B), is essential for the function of Sertoli cells to regulate spermatogenesis. Specifically, we generated Sertoli cell-specific Arid4b knockout (Arid4bSCKO) mice, and showed that the Arid4bSCKO male mice were completely infertile with impaired testis development and significantly reduced testis size. Importantly, severe structural defects accompanied by loss of germ cells and Sertoli cell-only phenotype were found in many seminiferous tubules of the Arid4bSCKO testes. In addition, maturation of Sertoli cells was significantly delayed in the Arid4bSCKO mice, associated with delayed onset of spermatogenesis. Spermatogenic progression was also defective, showing an arrest at the round spermatid stage in the Arid4bSCKO testes. Interestingly, we showed that ARID4B functions as a "coactivator" of androgen receptor and is required for optimal transcriptional activation of reproductive homeobox 5, an androgen receptor target gene specifically expressed in Sertoli cells and critical for spermatogenesis. Together, our study identified ARID4B to be a key regulator of Sertoli cell function important for male germ cell development.

  2. Nuclear receptor conformation, coregulators, and tamoxifen-resistant breast cancer.

    Science.gov (United States)

    Graham, J D; Bain, D L; Richer, J K; Jackson, T A; Tung, L; Horwitz, K B

    2000-01-01

    The development of tamoxifen resistance and consequent disease progression are common occurrences in breast cancers, often despite the continuing expression of estrogen receptors (ER). Tamoxifen is a mixed antagonist, having both agonist and antagonist properties. We have suggested that the development of tamoxifen resistance is associated with an increase in its agonist-like properties, resulting in loss of antagonist effects or even inappropriate tumor stimulation. Nuclear receptor function is influenced by a family of transcriptional coregulators, that either enhance or suppress transcriptional activity. Using a mixed antagonist-biased two-hybrid screening strategy, we identified two such proteins: the human homolog of the nuclear receptor corepressor, N-CoR, and a novel coactivator, L7/SPA (Switch Protein for Antagonists). In transcriptional studies, N-CoR suppressed the agonist properties of tamoxifen and RU486, and L7/SPA increased agonist effects. We speculated that the relative levels of these coactivators and corepressors may determine the balance of agonist and antagonist properties of mixed antagonists, such as tamoxifen. Using quantitative RT-PCR, we, therefore, measured the levels of transcripts encoding these coregulators, as well as the corepressor SMRT, and the coactivator SRC-1, in a small cohort of tamoxifen-resistant and sensitive breast tumors. The results suggest that tumor sensitivity to mixed antagonists may be governed by a complex set of transcription factors, which we are only now beginning to understand.

  3. FUS/TLS Is a Co-Activator of Androgen Receptor in Prostate Cancer Cells

    OpenAIRE

    Simon Haile; Aaron Lal; Jae-Kyung Myung; Sadar, Marianne D.

    2011-01-01

    Androgen receptor (AR) is a member of the nuclear receptor family of transcription factors. Upon binding to androgens, AR becomes transcriptionally active to regulate the expression of target genes that harbor androgen response elements (AREs) in their promoters and/or enhancers. AR is essential for the growth and survival of prostate cancer cells and is therefore a target for current and next-generation therapeutic modalities against prostate cancer. Pathophysiologically relevant protein-pro...

  4. A liver X receptor (LXR)-{beta} alternative splicing variant (LXRBSV) acts as an RNA co-activator of LXR-{beta}

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Koshi, E-mail: khashi@med.gunma-u.ac.jp [Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma 371-8511 (Japan); Ishida, Emi; Matsumoto, Shunichi; Shibusawa, Nobuyuki; Okada, Shuichi [Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma 371-8511 (Japan); Monden, Tsuyoshi [Department of Endocrinology and Metabolism, Dokkyo Medical College, Mibu, Tochigi (Japan); Satoh, Tetsurou; Yamada, Masanobu; Mori, Masatomo [Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma 371-8511 (Japan)

    2009-12-25

    We report the isolation and functional characterization of a novel transcriptional co-activator, termed LXRBSV. LXRBSV is an alternative splicing variant of liver X receptor (LXR)-{beta} LXRBSV has an intronic sequence between exons 2 and 3 in the mouse LXR-{beta} gene. The LXRBSV gene is expressed in various tissues including the liver and brain. We sub-cloned LXRBSV into pSG5, a mammalian expression vector, and LXRBSV in pSG5 augmented human Sterol Response Element Binding Protein (SREBP)-1c promoter activity in HepG2 cells in a ligand (TO901317) dependent manner. The transactivation mediated by LXRBSV is selective for LXR-{beta}. The LXRBSV protein was deduced to be 64 amino acids in length; however, a GAL4-LXRBSV fusion protein was not able to induce transactivation. Serial deletion constructs of LXRBSV demonstrated that the intronic sequence inserted in LXRBSV is required for its transactivation activity. An ATG mutant of LXRBSV was able to induce transactivation as wild type. Furthermore, LXRBSV functions in the presence of cycloheximide. Taken together, we have concluded that LXRBSV acts as an RNA transcript not as a protein. In the current study, we have demonstrated for the first time that an alternative splicing variant of a nuclear receptor acts as an RNA co-activator.

  5. Mechanism of Transcriptional Regulation by Androgen Receptor and its Coactivators in the Context of Chromatin

    Science.gov (United States)

    2002-07-01

    caso - reaction and the mixture was incubated for 20 min at roomteprtr.In co petition says, unlabeled ARE or TRE 󈧎 dex and flutamide. We are...activation and nuclear targeting sig- nals of the human androgen receptor. J Biol Chem 266: LNCaP cells were culture in Roswell Park Memorial Institute 510

  6. Nuclear localization of the transcriptional coactivator YAP is associated with invasive lobular breast cancer

    NARCIS (Netherlands)

    Vlug, E.J.; Ven, R.A. van de; Vermeulen, J.F.; Bult, P.; Diest, P.J. van; Derksen, P.W.B.

    2013-01-01

    BACKGROUND: Yes Associated Protein (YAP) has been implicated in the control of organ size by regulating cell proliferation and survival. YAP is a transcriptional coactivator that controls cellular responses through interaction with TEAD transcription factors in the nucleus, while its transcriptional

  7. Nuclear localization of the transcriptional coactivator YAP is associated with invasive lobular breast cancer

    NARCIS (Netherlands)

    Vlug, E.J.; Ven, R.A. van de; Vermeulen, J.F.; Bult, P.; Diest, P.J. van; Derksen, P.W.B.

    2013-01-01

    BACKGROUND: Yes Associated Protein (YAP) has been implicated in the control of organ size by regulating cell proliferation and survival. YAP is a transcriptional coactivator that controls cellular responses through interaction with TEAD transcription factors in the nucleus, while its transcriptional

  8. SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1.

    Science.gov (United States)

    Darvekar, Sagar Ramesh; Elvenes, Julianne; Brenne, Hanne Britt; Johansen, Terje; Sjøttem, Eva

    2014-01-01

    Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy.

  9. SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1.

    Directory of Open Access Journals (Sweden)

    Sagar Ramesh Darvekar

    Full Text Available Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy.

  10. SPBP Is a Sulforaphane Induced Transcriptional Coactivator of NRF2 Regulating Expression of the Autophagy Receptor p62/SQSTM1

    Science.gov (United States)

    Darvekar, Sagar Ramesh; Elvenes, Julianne; Brenne, Hanne Britt; Johansen, Terje; Sjøttem, Eva

    2014-01-01

    Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6–8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy. PMID:24416372

  11. Ligand-regulated association of ErbB-4 to the transcriptional co-activator YAP65 controls transcription at the nuclear level.

    Science.gov (United States)

    Omerovic, Jasminka; Puggioni, Eleonora M R; Napoletano, Silvia; Visco, Vincenzo; Fraioli, Rocco; Frati, Luigi; Gulino, Alberto; Alimandi, Maurizio

    2004-04-01

    It has been proposed that ligand-dependent Regulated Intramembrane Proteolysis (RIP) of ErbB-4 receptors generates 80 kDa Intra-Cellular Domains (E4.ICDs) that relocate to the nuclear compartments where they implement the signaling abilities of the ErbB-4 receptors. The E4.ICD may directly regulate gene transcription or, in an alternative scenario, the tyrosine kinase activity of E4.ICDs may target proteins involved in transcriptional regulation upon its relocation into the nucleus. We have identified the transcriptional coactivator YAP65, here referred as YAP (Yes Associated Protein), as binding partner of ErbB-4 in a two hybrid screening in yeast. Interaction between YAP and ErbB-4 occurs via the WW domain of YAP and the PPPPY at positions 1297-1301 and the PPPAY at positions 1052-1056 of the amino acid sequence of the Cyt-1 isoform of ErbB-4. Stechiometry of binding is regulated by the ligand-dependent phosphorylation of Tyr 1056 in the PPPAYTPM module that function as "biochemical switch" to decrease the association of YAP to ErbB-4. In principle, this novel interaction highlights new mechanisms of signaling propagation from the ErbB-4 receptors, offering supporting evidences that the E4.ICDs forms released following ligand-receptor engagement may recruit YAP and relocate to the nucleus to implement or regulate transcription.

  12. Steroid receptor coactivators 1 and 2 mediate fetal-to-maternal signaling that initiates parturition

    Science.gov (United States)

    Gao, Lu; Rabbitt, Elizabeth H.; Condon, Jennifer C.; Renthal, Nora E.; Johnston, John M.; Mitsche, Matthew A.; Chambon, Pierre; Xu, Jianming; O’Malley, Bert W.; Mendelson, Carole R.

    2015-01-01

    The precise mechanisms that lead to parturition are incompletely defined. Surfactant protein-A (SP-A), which is secreted by fetal lungs into amniotic fluid (AF) near term, likely provides a signal for parturition; however, SP-A–deficient mice have only a relatively modest delay (~12 hours) in parturition, suggesting additional factors. Here, we evaluated the contribution of steroid receptor coactivators 1 and 2 (SRC-1 and SRC-2), which upregulate SP-A transcription, to the parturition process. As mice lacking both SRC-1 and SRC-2 die at birth due to respiratory distress, we crossed double-heterozygous males and females. Parturition was severely delayed (~38 hours) in heterozygous dams harboring SRC-1/-2–deficient embryos. These mothers exhibited decreased myometrial NF-κB activation, PGF2α, and expression of contraction-associated genes; impaired luteolysis; and elevated circulating progesterone. These manifestations also occurred in WT females bearing SRC-1/-2 double-deficient embryos, indicating that a fetal-specific defect delayed labor. SP-A, as well as the enzyme lysophosphatidylcholine acyltransferase-1 (LPCAT1), required for synthesis of surfactant dipalmitoylphosphatidylcholine, and the proinflammatory glycerophospholipid platelet-activating factor (PAF) were markedly reduced in SRC-1/-2–deficient fetal lungs near term. Injection of PAF or SP-A into AF at 17.5 days post coitum enhanced uterine NF-κB activation and contractile gene expression, promoted luteolysis, and rescued delayed parturition in SRC-1/-2–deficient embryo-bearing dams. These findings reveal that fetal lungs produce signals to initiate labor when mature and that SRC-1/-2–dependent production of SP-A and PAF is crucial for this process. PMID:26098214

  13. Steroid receptor coactivators 1 and 2 mediate fetal-to-maternal signaling that initiates parturition.

    Science.gov (United States)

    Gao, Lu; Rabbitt, Elizabeth H; Condon, Jennifer C; Renthal, Nora E; Johnston, John M; Mitsche, Matthew A; Chambon, Pierre; Xu, Jianming; O'Malley, Bert W; Mendelson, Carole R

    2015-07-01

    The precise mechanisms that lead to parturition are incompletely defined. Surfactant protein-A (SP-A), which is secreted by fetal lungs into amniotic fluid (AF) near term, likely provides a signal for parturition; however, SP-A-deficient mice have only a relatively modest delay (~12 hours) in parturition, suggesting additional factors. Here, we evaluated the contribution of steroid receptor coactivators 1 and 2 (SRC-1 and SRC-2), which upregulate SP-A transcription, to the parturition process. As mice lacking both SRC-1 and SRC-2 die at birth due to respiratory distress, we crossed double-heterozygous males and females. Parturition was severely delayed (~38 hours) in heterozygous dams harboring SRC-1/-2-deficient embryos. These mothers exhibited decreased myometrial NF-κB activation, PGF2α, and expression of contraction-associated genes; impaired luteolysis; and elevated circulating progesterone. These manifestations also occurred in WT females bearing SRC-1/-2 double-deficient embryos, indicating that a fetal-specific defect delayed labor. SP-A, as well as the enzyme lysophosphatidylcholine acyltransferase-1 (LPCAT1), required for synthesis of surfactant dipalmitoylphosphatidylcholine, and the proinflammatory glycerophospholipid platelet-activating factor (PAF) were markedly reduced in SRC-1/-2-deficient fetal lungs near term. Injection of PAF or SP-A into AF at 17.5 days post coitum enhanced uterine NF-κB activation and contractile gene expression, promoted luteolysis, and rescued delayed parturition in SRC-1/-2-deficient embryo-bearing dams. These findings reveal that fetal lungs produce signals to initiate labor when mature and that SRC-1/-2-dependent production of SP-A and PAF is crucial for this process.

  14. Structure-activity relationship of benzodiazepine derivatives as LXXLL peptide mimetics that inhibit the interaction of vitamin D receptor with coactivators.

    Science.gov (United States)

    Mita, Yusuke; Dodo, Kosuke; Noguchi-Yachide, Tomomi; Hashimoto, Yuichi; Ishikawa, Minoru

    2013-02-15

    Suppression of vitamin D receptor (VDR)-mediated transcription is expected to be of therapeutic value in Paget's disease of bone. It is known that interaction between VDR and coactivators is necessary for VDR transactivation, and the interaction occurs when VDR recognizes an LXXLL peptide motif of coactivators. We previously reported that benzodiazepine derivatives designed as LXXLL peptide mimetics inhibited the interaction of VDR and coactivators, and reduced VDR transcription. Here, we investigated the structure-activity relationship of 7- and 8-substituted benzodiazepine derivatives, and established that the amino group at the 8-position is critical for the inhibitory activity.

  15. Troglitazone induces cytotoxicity in part by promoting the degradation of peroxisome proliferator-activated receptor γ co-activator-1α protein.

    Science.gov (United States)

    Liao, Xuemei; Wang, Yanfei; Wong, Chi-Wai

    2010-10-01

    Troglitazone (Tro), rosiglitazone (Rosi) and pioglitazone (Pio) are anti-diabetic thiazolidinediones that function as ligands for peroxisome proliferator-activated receptor γ (PPARγ); however, Tro has been withdrawn from the market due to liver toxicity issues. Mitochondrial dysfunction induced by Tro has been suggested to be an important mechanism behind its cytotoxicity. Constitutively active nuclear hormone receptors, oestrogen-related receptor α and γ are thought to regulate mitochondrial mass and oxidative phosphorylation together with their co-activators PPARγ co-activator-1α and -1β (PGC-1α and PGC-1β). Hence, in this study, we investigated whether Tro affects the expression and activity levels of these regulators. Cellular viability was measured by an ATP-based assay. Mitochondrial mass and reactive oxygen species (ROS) were quantified by two different fluorogenic probes. Apoptosis was measured by an Annexin-V-based kit. Gene expression at the levels of mRNA and protein was measured by quantitative RT-PCR and Western analysis. Over-expression of PGC-1α was mediated by an adenovirus. Tro, but not Rosi or Pio, selectively stimulated PGC-1α protein degradation. As a result, Tro reduced mitochondrial mass, and superoxide dismutases 1 and 2 expressions, but induced ROS to initiate apoptosis. Using a ubiquitin-proteasome inhibitor MG132, it was established that blocking PGC-1α degradation partially suppressed the reduction of mitochondrial mass. Importantly, over-expressing PGC-1α partially restored the Tro-suppressed mitochondrial mass and attenuated the cytotoxic effects of Tro. Collectively, these results suggest that PGC-1α degradation is an important mechanism behind the cytotoxic effects of Tro in the liver. © 2010 The Authors. British Journal of Pharmacology © 2010 The British Pharmacological Society.

  16. The ERα coactivator, HER4/4ICD, regulates progesterone receptor expression in normal and malignant breast epithelium

    Directory of Open Access Journals (Sweden)

    Howard Beatrice A

    2010-06-01

    Full Text Available Abstract The HER4 intracellular domain (4ICD is a potent estrogen receptor (ERα coactivator with activities in breast cancer and the developing mammary gland that appear to overlap with progesterone receptor (PgR. In fact, 4ICD has recently emerged as an important regulator and predictor of tamoxifen response, a role previously thought to be fulfilled by PgR. Here we investigated the possibility that the 4ICD coactivator regulates PgR expression thereby providing a mechanistic explanation for their partially overlapping activities in breast cancer. We show that 4ICD is both sufficient and necessary to potentiate estrogen stimulation of gene expression. Suppression of HER4/4ICD expression in the MCF-7 breast tumor cell line completely eliminated estrogen stimulated expression of PgR. In addition, the HER4/4ICD negative MCF-7 variant, TamR, failed to express PgR in response to estrogen. Reintroduction of wild-type HER4 but not the γ-secretase processing mutant HER4V673I into the TamR cell line restored PgR expression indicating that 4ICD is an essential PgR coactivator in breast tumor cells. These results were substantiated in vivo using two different physiologically relevant experimental systems. In the mouse mammary gland estrogen regulates expression of PgR-A whereas expression of PgR-B is estrogen independent. Consistent with a role for 4ICD in estrogen regulated PgR expression in vivo, PgR-A, but not PgR-B, expression was abolished in HER4-null mouse mammary glands during pregnancy. Coexpression of PgR and 4ICD is also commonly observed in ERα positive breast carcinomas. Using quantitative AQUA IHC technology we found that 4ICD potentiated PgR expression in primary breast tumors and the highest levels of PgR expression required coexpression of ERα and the 4ICD coactivator. In summary, our results provide compelling evidence that 4ICD is a physiologically important ERα coactivator and 4ICD cooperates with ERα to potentiate PgR expression

  17. Nuclear hormone receptors in podocytes

    Directory of Open Access Journals (Sweden)

    Khurana Simran

    2012-09-01

    Full Text Available Abstract Nuclear receptors are a family of ligand-activated, DNA sequence-specific transcription factors that regulate various aspects of animal development, cell proliferation, differentiation, and homeostasis. The physiological roles of nuclear receptors and their ligands have been intensively studied in cancer and metabolic syndrome. However, their role in kidney diseases is still evolving, despite their ligands being used clinically to treat renal diseases for decades. This review will discuss the progress of our understanding of the role of nuclear receptors and their ligands in kidney physiology with emphasis on their roles in treating glomerular disorders and podocyte injury repair responses.

  18. Nuclear Receptor Signaling Atlas (NURSA)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Nuclear Receptor Signaling Atlas (NURSA) is designed to foster the development of a comprehensive understanding of the structure, function, and role in disease...

  19. Downregulation of steroid receptor coactivator-2 modulates estrogen-responsive genes and stimulates proliferation of mcf-7 breast cancer cells.

    Science.gov (United States)

    Fenne, Ingvild S; Helland, Thomas; Flågeng, Marianne H; Dankel, Simon N; Mellgren, Gunnar; Sagen, Jørn V

    2013-01-01

    The p160/Steroid Receptor Coactivators SRC-1, SRC-2/GRIP1, and SRC-3/AIB1 are important regulators of Estrogen Receptor alpha (ERα) activity. However, whereas the functions of SRC-1 and SRC-3 in breast tumourigenesis have been extensively studied, little is known about the role of SRC-2. Previously, we reported that activation of the cAMP-dependent protein kinase, PKA, facilitates ubiquitination and proteasomal degradation of SRC-2 which in turn leads to inhibition of SRC-2-coactivation of ERα and changed expression of the ERα target gene, pS2. Here we have characterized the global program of transcription in SRC-2-depleted MCF-7 breast cancer cells using short-hairpin RNA technology, and in MCF-7 cells exposed to PKA activating agents. In order to identify genes that may be regulated through PKA-induced downregulation of SRC-2, overlapping transcriptional targets in response to the respective treatments were characterized. Interestingly, we observed decreased expression of several breast cancer tumour suppressor genes (e.g., TAGLN, EGR1, BCL11b, CAV1) in response to both SRC-2 knockdown and PKA activation, whereas the expression of a number of other genes implicated in cancer progression (e.g., RET, BCAS1, TFF3, CXCR4, ADM) was increased. In line with this, knockdown of SRC-2 also stimulated proliferation of MCF-7 cells. Together, these results suggest that SRC-2 may have an antiproliferative function in breast cancer cells.

  20. The Use of the LanthaScreen TR-FRET CAR Coactivator Assay in the Characterization of Constitutive Androstane Receptor (CAR) Inverse Agonists

    Science.gov (United States)

    Carazo, Alejandro; Pávek, Petr

    2015-01-01

    The constitutive androstane receptor (CAR) is a critical nuclear receptor in the gene regulation of xenobiotic and endobiotic metabolism. The LanthaScreenTM TR-FRET CAR coactivator assay provides a simple and reliable method to analyze the affinity of a ligand to the human CAR ligand-binding domain (LBD) with no need to use cellular models. This in silico assay thus enables the study of direct CAR ligands and the ability to distinguish them from the indirect CAR activators that affect the receptor via the cell signaling-dependent phosphorylation of CAR in cells. For the current paper we characterized the pharmacodynamic interactions of three known CAR inverse agonists/antagonists—PK11195, clotrimazole and androstenol—with the prototype agonist CITCO (6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde-O-(3,4-dichlorobenzyl)oxime) using the TR-FRET LanthaScreenTM assay. We have confirmed that all three compounds are inverse agonists of human CAR, with IC50 0.51, 0.005, and 0.35 μM, respectively. All the compounds also antagonize the CITCO-mediated activation of CAR, but only clotrimazole was capable to completely reverse the effect of CITCO in the tested concentrations. Thus this method allows identifying not only agonists, but also antagonists and inverse agonists for human CAR as well as to investigate the nature of the pharmacodynamic interactions of CAR ligands. PMID:25905697

  1. Peroxisome Proliferator-Activated Receptor γCoactivator 1 α and Insulin Resistance%PGC-1α与胰岛素抵抗

    Institute of Scientific and Technical Information of China (English)

    马慧娟

    2011-01-01

    Peroxisome proliferator-activated receptor "y coactivator la ( PGC-la) is a nuclear transcription co-activator factor. PGC-la can play different functions when combined with different transcription factors. Additionally, genetic and environmental factors can affect the expression of PGC-la. The expression of PGC-la noticeably decreased in patients with insulin resistance and type 2 diabetes. The expression of PGC-la and insulin sensitivity decreased with high lipid intervention. However, physical exercise can increase the expression and improve insulin resistance. The gene polymorphism of PGC-la is closely related to insulin resistance and type 2 diabetes.%过氧化物酶体增生物激活受体y共激活因子1α(PGC-1α),是一种核转录共激活因子,它与不同的转录因子结合发挥不同的功能.PGC-1α在胰岛素抵抗和2型糖尿病人群的表达下降.环境和遗传因素均可影响PGC-1α的表达,高脂使PGC-1α表达下降,降低胰岛素敏感性,而运动可增加PGC-1α表达,改善胰岛素抵抗.PGC-1α的基因多态性与胰岛素抵抗、2型糖尿病密切相关.

  2. Ligand-controlled interaction of histone acetyltransferase binding to ORC-1 (HBO1) with the N-terminal transactivating domain of progesterone receptor induces steroid receptor coactivator 1-dependent coactivation of transcription

    NARCIS (Netherlands)

    M. Georgiakaki (Maria); L.J. Blok (Leen); R. Milgrom (Roni); M. Lombès (Marc); A. Guiochon-Mantel (Anne); H. Loosfelt (Hugues); N. Chabbert-Buffet (Nathalie); B. Dasen (Boris); G. Meduri (Geri); S. Wenk (Sandra); L. Rajhi (Leila); L. Amazit (Larbi); A. Chauchereau (Anne); C.W. Burger (Curt)

    2006-01-01

    textabstractModulators of cofactor recruitment by nuclear receptors are expected to play an important role in the coordination of hormone-induced transactivation processes. To identify such factors interacting with the N-terminal domain (NTD) of the progesterone receptor (PR), we used this domain as

  3. Ligand-controlled interaction of histone acetyltransferase binding to ORC-1 (HBO1) with the N-terminal transactivating domain of progesterone receptor induces steroid receptor coactivator 1-dependent coactivation of transcription

    NARCIS (Netherlands)

    M. Georgiakaki (Maria); L.J. Blok (Leen); R. Milgrom (Roni); M. Lombès (Marc); A. Guiochon-Mantel (Anne); H. Loosfelt (Hugues); N. Chabbert-Buffet (Nathalie); B. Dasen (Boris); G. Meduri (Geri); S. Wenk (Sandra); L. Rajhi (Leila); L. Amazit (Larbi); A. Chauchereau (Anne); C.W. Burger (Curt)

    2006-01-01

    textabstractModulators of cofactor recruitment by nuclear receptors are expected to play an important role in the coordination of hormone-induced transactivation processes. To identify such factors interacting with the N-terminal domain (NTD) of the progesterone receptor (PR), we used this domain as

  4. Role of the N-terminal activation domain of coactivator CoCoA in mediating transcriptional activation by β-catenin*

    OpenAIRE

    Yang, Catherine K.; Kim, Jeong Hoon; Stallcup, Michael R

    2006-01-01

    The coiled-coil coactivator (CoCoA) is involved in transcriptional activation of target genes by nuclear receptors and the xenobiotic aryl hydrocarbon receptor, as well as target genes of the Wnt signaling pathway, which is mediated by the lymphocyte enhancer factor (LEF)/T cell factor transcription factors and the coactivator β-catenin. The recruitment of CoCoA by nuclear receptors is accomplished by the interaction of the central coiled-coiled domain of CoCoA with p160 coactivators; the C-t...

  5. Steroid receptor coactivators, HER-2 and HER-3 expression is stimulated by tamoxifen treatment in DMBA-induced breast cancer

    Directory of Open Access Journals (Sweden)

    Moi Line L

    2012-06-01

    Full Text Available Abstract Background Steroid receptor coactivators (SRCs may modulate estrogen receptor (ER activity and the response to endocrine treatment in breast cancer, in part through interaction with growth factor receptor signaling pathways. In the present study the effects of tamoxifen treatment on the expression of SRCs and human epidermal growth factor receptors (HERs were examined in an animal model of ER positive breast cancer. Methods Sprague-Dawley rats with DMBA-induced breast cancer were randomized to 14 days of oral tamoxifen 40 mg/kg bodyweight/day or vehicle only (controls. Tumors were measured throughout the study period. Blood samples and tumor tissue were collected at sacrifice and tamoxifen and its main metabolites were quantified using LC-MS/MS. The gene expression in tumor of SRC-1, SRC-2/transcription intermediary factor-2 (TIF-2, SRC-3/amplified in breast cancer 1 (AIB1, ER, HER-1, -2, -3 and HER-4, as well as the transcription factor Ets-2, was measured by real-time RT-PCR. Protein levels were further assessed by Western blotting. Results Tamoxifen and its main metabolites were detected at high concentrations in serum and accumulated in tumor tissue in up to tenfolds the concentration in serum. Mean tumor volume/rat decreased in the tamoxifen treated group, but continued to increase in controls. The mRNA expression levels of SRC-1 (P = 0.035, SRC-2/TIF-2 (P = 0.002, HER-2 (P = 0.035 and HER-3 (P = 0.006 were significantly higher in tamoxifen treated tumors compared to controls, and the results were confirmed at the protein level using Western blotting. SRC-3/AIB1 protein was also higher in tamoxifen treated tumors. SRC-1 and SRC-2/TIF-2 mRNA levels were positively correlated with each other and with HER-2 (P ≤ 0.001, and the HER-2 mRNA expression correlated with the levels of the other three HER family members (P P  Conclusions The expression of SRCs and HER-2 and -3 is stimulated by tamoxifen treatment

  6. Studies of the Gly482Ser polymorphism of the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) gene in Danish subjects with the metabolic syndrome

    DEFF Research Database (Denmark)

    Ambye, Louise; Rasmussen, Susanne; Fenger, Mogens;

    2005-01-01

    The peroxisome proliferator-activated receptor gamma co-activator 1alpha (PGC-1alpha) is a novel transcriptional co-activator that holds an important role in lipid and glucose metabolism. PGC-1alpha is a candidate gene for the metabolic syndrome (MS) as well as type 2 diabetes. Recent studies...

  7. WW domain binding protein-2, an E6-associated protein interacting protein, acts as a coactivator of estrogen and progesterone receptors.

    Science.gov (United States)

    Dhananjayan, Sarath C; Ramamoorthy, Sivapriya; Khan, Obaid Y; Ismail, Ayesha; Sun, Jun; Slingerland, Joyce; O'Malley, Bert W; Nawaz, Zafar

    2006-10-01

    WW domain binding protein-2 (WBP-2) was cloned as an E6-associated protein interacting protein, and its role in steroid hormone receptors functions was investigated. We show that WBP-2 specifically enhanced the transactivation functions of progesterone receptor (PR) and estrogen receptor (ER), whereas it did not have any significant effect on the androgen receptor, glucocorticoid receptor, or the activation functions of p53 and VP-16. Depletion of endogenous WBP-2 with small interfering RNAs indicated that WBP-2 was required for the proper functioning of PR and ER. We also demonstrated that WBP-2 contains an intrinsic activation domain. Moreover, chromatin immunoprecipitation assays demonstrate the hormone-dependent recruitment of WBP-2 onto an estrogen-responsive promoter. Mutational analysis suggests that one of three polyproline (PY) motifs of WBP-2 is essential for its coactivation and intrinsic activation functions. We show that WBP-2 and E6-associated protein each enhance PR function, and their effect on PR action are additive when coexpressed, suggesting a common signaling pathway. In this study, we also demonstrate that the WBP-2 binding protein, Yes kinase-associated protein (YAP) enhances PR transactivation, but YAP's coactivation function is absolutely dependent on WBP-2. Taken together, our data establish the role of WBP-2 and YAP as coactivators for ER and PR transactivation pathways.

  8. Isoform switching of steroid receptor co-activator-1 attenuates glucocorticoid-induced anxiogenic amygdala CRH expression.

    Science.gov (United States)

    Zalachoras, I; Verhoeve, S L; Toonen, L J; van Weert, L T C M; van Vlodrop, A M; Mol, I M; Meelis, W; de Kloet, E R; Meijer, O C

    2016-12-01

    Maladaptive glucocorticoid effects contribute to stress-related psychopathology. The glucocorticoid receptor (GR) that mediates many of these effects uses multiple signaling pathways. We have tested the hypothesis that manipulation of downstream factors ('coregulators') can abrogate potentially maladaptive GR-mediated effects on fear-motivated behavior that are linked to corticotropin releasing hormone (CRH). For this purpose the expression ratio of two splice variants of steroid receptor coactivator-1 (SRC-1) was altered via antisense-mediated 'exon-skipping' in the central amygdala of the mouse brain. We observed that a change in splicing towards the repressive isoform SRC-1a strongly reduced glucocorticoid-induced responsiveness of Crh mRNA expression and increased methylation of the Crh promoter. The transcriptional GR target gene Fkbp5 remained responsive to glucocorticoids, indicating gene specificity of the effect. The shift of the SRC-1 splice variants altered glucocorticoid-dependent exploratory behavior and attenuated consolidation of contextual fear memory. In conclusion, our findings demonstrate that manipulation of GR signaling pathways related to the Crh gene can selectively diminish potentially maladaptive effects of glucocorticoids.

  9. Targeting Nuclear Receptors with Marine Natural Products

    Directory of Open Access Journals (Sweden)

    Chunyan Yang

    2014-01-01

    Full Text Available Nuclear receptors (NRs are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators.

  10. A polymorphic autoregulatory hormone response element in the human estrogen-related receptor alpha (ERRalpha) promoter dictates peroxisome proliferator-activated receptor gamma coactivator-1alpha control of ERRalpha expression.

    Science.gov (United States)

    Laganière, Josée; Tremblay, Gilles B; Dufour, Catherine R; Giroux, Sylvie; Rousseau, François; Giguère, Vincent

    2004-04-30

    The orphan nuclear estrogen-related receptor alpha (ERRalpha) and transcriptional cofactor peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) are involved in the regulation of energy metabolism. Recently, extensive cross-talk between PGC-1alpha and ERRalpha has been demonstrated. The presence of PGC-1alpha is associated with an elevated expression of ERRalpha, and the two proteins can influence the transcriptional activities of one another. Using a candidate gene approach to detect regulatory variants within genes encoding nuclear receptors, we have identified a 23-bp sequence (ESRRA23) containing two nuclear receptor recognition half-site motifs that is present in 1-4 copies within the promoter of the human ESRRA gene encoding ERRalpha. The ESRRA23 sequence contains a functional ERR response element that is specifically bound by ERRalpha, and chromatin immunoprecipitation shows that endogenous ERRalpha occupies its own promoter in vivo. Strikingly, introduction of PGC-1alpha in HeLa cells by transient transfection induces the activity of the ESRRA promoter in a manner that is dependent on the presence of the ESRRA23 element and on its dosage. Coexpression of ERRalpha and PGC-1alpha results in a synergistic activation of the ESRRA promoter. In experiments using ERRalpha null fibroblasts, the ability of PGC-1alpha to stimulate the ESRRA promoter is considerably reduced but can be restored by addition of ERRalpha. Taken together, these results demonstrate that an interdependent ERRalpha/PGC-1alpha-based transcriptional pathway targets the ESRRA23 element to dictate the level of ERRalpha expression. This study further suggests that this regulatory polymorphism may provide differential responses to ERRalpha/PGC-1alpha-mediated metabolic cues in the human population.

  11. PPARs: Nuclear Receptors Controlled by, and Controlling, Nutrient Handling through Nuclear and Cytosolic Signaling

    Directory of Open Access Journals (Sweden)

    Maria Moreno

    2010-01-01

    Full Text Available Peroxisome proliferator-activated receptors (PPARs, which are known to regulate lipid homeostasis, are tightly controlled by nutrient availability, and they control nutrient handling. In this paper, we focus on how nutrients control the expression and action of PPARs and how cellular signaling events regulate the action of PPARs in metabolically active tissues (e.g., liver, skeletal muscle, heart, and white adipose tissue. We address the structure and function of the PPARs, and their interaction with other nuclear receptors, including PPAR cross-talk. We further discuss the roles played by different kinase pathways, including the extracellular signal-regulated kinases/mitogen-activated protein kinase (ERK MAPK, AMP-activated protein kinase (AMPK, Akt/protein kinase B (Akt/PKB, and the NAD+-regulated protein deacetylase SIRT1, serving to control the activity of the PPARs themselves as well as that of a key nutrient-related PPAR coactivator, PPARγ coactivator-1α (PGC-1α. We also highlight how currently applied nutrigenomic strategies will increase our understanding on how nutrients regulate metabolic homeostasis through PPAR signaling.

  12. Nuclear Receptors, RXR, and the Big Bang.

    Science.gov (United States)

    Evans, Ronald M; Mangelsdorf, David J

    2014-03-27

    Isolation of genes encoding the receptors for steroids, retinoids, vitamin D, and thyroid hormone and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors and, in particular, of the retinoid X receptor (RXR) positioned nuclear receptors at the epicenter of the "Big Bang" of molecular endocrinology. This Review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multicellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism.

  13. Argan oil prevents down-regulation induced by endotoxin on liver fatty acid oxidation and gluconeogenesis and on peroxisome proliferator-activated receptor gamma coactivator-1α, (PGC-1α, peroxisome proliferator-activated receptor α (PPARα and estrogen related receptor α (ERRα

    Directory of Open Access Journals (Sweden)

    Riad El Kebbaj

    2015-01-01

    Full Text Available In patients with sepsis, liver metabolism and its capacity to provide other organs with energetic substrates are impaired. This and many other pathophysiological changes seen in human patients are reproduced in mice injected with purified endotoxin (lipopolysaccharide, LPS. In the present study, down-regulation of genes involved in hepatic fatty acid oxidation (FAOx and gluconeogenesis in mice exposed to LPS was challenged by nutritional intervention with Argan oil. Mice given a standard chow supplemented or not with either 6% (w/w Argan oil (AO or 6% (w/w olive oil (OO prior to exposure to LPS were explored for liver gene expressions assessed by mRNA transcript levels and/or enzyme activities. AO (or OO food supplementation reveals that, in LPS-treated mice, hepatic expression of genes involved in FAOx and gluconeogenesis was preserved. This preventive protection might be related to the recovery of the gene expressions of nuclear receptors peroxisome proliferator-activated receptor α (PPARα and estrogen related receptor α (ERRα and their coactivator peroxisome proliferator-activated receptor gamma coactivator-1α, (PGC-1α. These preventive mechanisms conveyed by AO against LPS-induced metabolic dysregulation might add new therapeutic potentialities in the management of human sepsis.

  14. A toll-like receptor 2 pathway regulates the Ppargc1a/b metabolic co-activators in mice with Staphylococcal aureus sepsis.

    Directory of Open Access Journals (Sweden)

    Timothy E Sweeney

    Full Text Available Activation of the host antibacterial defenses by the toll-like receptors (TLR also selectively activates energy-sensing and metabolic pathways, but the mechanisms are poorly understood. This includes the metabolic and mitochondrial biogenesis master co-activators, Ppargc1a (PGC-1α and Ppargc1b (PGC-1β in Staphylococcus aureus (S. aureus sepsis. The expression of these genes in the liver is markedly attenuated inTLR2(-/- mice and markedly accentuated in TLR4(-/- mice compared with wild type (WT mice. We sought to explain this difference by using specific TLR-pathway knockout mice to test the hypothesis that these co-activator genes are directly regulated through TLR2 signaling. By comparing their responses to S. aureus with WT mice, we found that MyD88-deficient and MAL-deficient mice expressed hepatic Ppargc1a and Ppargc1b normally, but that neither gene was activated in TRAM-deficient mice. Ppargc1a/b activation did not require NF-kβ, but did require an interferon response factor (IRF, because neither gene was activated in IRF-3/7 double-knockout mice in sepsis, but both were activated normally in Unc93b1-deficient (3d mice. Nuclear IRF-7 levels in TLR2(-/- and TLR4(-/- mice decreased and increased respectively post-inoculation and IRF-7 DNA-binding at the Ppargc1a promoter was demonstrated by chromatin immunoprecipitation. Also, a TLR2-TLR4-TRAM native hepatic protein complex was detected by immunoprecipitation within 6 h of S. aureus inoculation that could support MyD88-independent signaling to Ppargc1a/b. Overall, these findings disclose a novel MyD88-independent pathway in S. aureus sepsis that links TLR2 and TLR4 signaling in innate immunity to Ppargc1a/b gene regulation in a critical metabolic organ, the liver, by means of TRAM, TRIF, and IRF-7.

  15. Computational Characterization and Prediction of Estrogen Receptor Coactivator Binding Site Inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, B J; Kulp, K S; Cosman, M; Lightstone, F C

    2005-08-26

    Many carcinogens have been shown to cause tissue specific tumors in animal models. The mechanism for this specificity has not been fully elucidated and is usually attributed to differences in organ metabolism. For heterocyclic amines, potent carcinogens that are formed in well-done meat, the ability to either bind to the estrogen receptor and activate or inhibit an estrogenic response will have a major impact on carcinogenicity. Here we describe our work with the human estrogen receptor alpha (hERa) and the mutagenic/carcinogenic heterocyclic amines PhIP, MeIQx, IFP, and the hydroxylated metabolite of PhIP, N2-hydroxy-PhIP. We found that PhIP, in contrast to the other heterocyclic amines, increased cell-proliferation in MCF-7 human breast cancer cells and activated the hERa receptor. We show mechanistic data supporting this activation both computationally by homology modeling and docking, and by NMR confirmation that PhIP binds with the ligand binding domain (LBD). This binding competes with estradiol (E2) in the native E2 binding cavity of the receptor. We also find that other heterocyclic amines and N2-hydroxy-PhIP inhibit ER activation presumably by binding into another cavity on the LBD. Moreover, molecular dynamics simulations of inhibitory heterocyclic amines reveal a disruption of the surface of the receptor protein involved with protein-protein signaling. We therefore propose that the mechanism for the tissue specific carcinogenicity seen in the rat breast tumors and the presumptive human breast cancer associated with the consumption of well-done meat maybe mediated by this receptor activation.

  16. Peroxisome Proliferator-activated ReceptorCoactivator 1-α (PGC1α) Protects against Experimental Murine Colitis*

    Science.gov (United States)

    Cunningham, Kellie E.; Vincent, Garret; Sodhi, Chhinder P.; Novak, Elizabeth A.; Ranganathan, Sarangarajan; Egan, Charlotte E.; Stolz, Donna Beer; Rogers, Matthew B.; Firek, Brian; Morowitz, Michael J.; Gittes, George K.; Zuckerbraun, Brian S.; Hackam, David J.; Mollen, Kevin P.

    2016-01-01

    Peroxisome proliferator-activated receptorcoactivator 1-α (PGC1α) is the primary regulator of mitochondrial biogenesis and was recently found to be highly expressed within the intestinal epithelium. PGC1α is decreased in the intestinal epithelium of patients with inflammatory bowel disease, but its role in pathogenesis is uncertain. We now hypothesize that PGC1α protects against the development of colitis and helps to maintain the integrity of the intestinal barrier. We selectively deleted PGC1α from the intestinal epithelium of mice by breeding a PGC1αloxP/loxP mouse with a villin-cre mouse. Their progeny (PGC1αΔIEC mice) were subjected to 2% dextran sodium sulfate (DSS) colitis for 7 days. The SIRT1 agonist SRT1720 was used to enhance PGC1α activation in wild-type mice during DSS exposure. Mice lacking PGC1α within the intestinal epithelium were more susceptible to DSS colitis than their wild-type littermates. Pharmacologic activation of PGC1α successfully ameliorated disease and restored mitochondrial integrity. These findings suggest that a depletion of PGC1α in the intestinal epithelium contributes to inflammatory changes through a failure of mitochondrial structure and function as well as a breakdown of the intestinal barrier, which leads to increased bacterial translocation. PGC1α induction helps to maintain mitochondrial integrity, enhance intestinal barrier function, and decrease inflammation. PMID:26969166

  17. TIP30 interacts with an estrogen receptor alpha-interacting coactivator CIA and regulates c-myc transcription.

    Science.gov (United States)

    Jiang, Chao; Ito, Mitsuhiro; Piening, Valerie; Bruck, Kristy; Roeder, Robert G; Xiao, Hua

    2004-06-25

    Deregulation of c-myc expression is implicated in the pathogenesis of many neoplasias. Estrogen receptor alpha (ERalpha) can increase the rate of c-myc transcription through the recruitment of a variety of cofactors to the promoter, yet the precise roles of these cofactors in transcription and tumorigenesis are largely unknown. We show here that a putative tumor suppressor TIP30, also called CC3 or Htatip2, interacts with an ERalpha-interacting coactivator CIA. Using chromatin immunoprecipitation assays, we demonstrate that TIP30 and CIA are distinct cofactors that are dynamically associated with the promoter and downstream regions of the c-myc gene in response to estrogen. Both TIP30 and CIA are recruited to the c-myc gene promoter by liganded ERalpha in the second transcription cycle. TIP30 overexpression represses ERalpha-mediated c-myc transcription, whereas TIP30 deficiency enhances c-myc transcription in both the absence and presence of estrogen. Ectopic CIA cooperates with TIP30 to repress ERalpha-mediated c-myc transcription. Moreover, virgin TIP30 knockout mice exhibit increased c-myc expression in mammary glands. Together, these results reveal an important role for TIP30 in the regulation of ERalpha-mediated c-myc transcription and suggest a mechanism for tumorigenesis promoted by TIP30 deficiency.

  18. Nuclear receptors and nonalcoholic fatty liver disease.

    Science.gov (United States)

    Cave, Matthew C; Clair, Heather B; Hardesty, Josiah E; Falkner, K Cameron; Feng, Wenke; Clark, Barbara J; Sidey, Jennifer; Shi, Hongxue; Aqel, Bashar A; McClain, Craig J; Prough, Russell A

    2016-09-01

    Nuclear receptors are transcription factors which sense changing environmental or hormonal signals and effect transcriptional changes to regulate core life functions including growth, development, and reproduction. To support this function, following ligand-activation by xenobiotics, members of subfamily 1 nuclear receptors (NR1s) may heterodimerize with the retinoid X receptor (RXR) to regulate transcription of genes involved in energy and xenobiotic metabolism and inflammation. Several of these receptors including the peroxisome proliferator-activated receptors (PPARs), the pregnane and xenobiotic receptor (PXR), the constitutive androstane receptor (CAR), the liver X receptor (LXR) and the farnesoid X receptor (FXR) are key regulators of the gut:liver:adipose axis and serve to coordinate metabolic responses across organ systems between the fed and fasting states. Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and may progress to cirrhosis and even hepatocellular carcinoma. NAFLD is associated with inappropriate nuclear receptor function and perturbations along the gut:liver:adipose axis including obesity, increased intestinal permeability with systemic inflammation, abnormal hepatic lipid metabolism, and insulin resistance. Environmental chemicals may compound the problem by directly interacting with nuclear receptors leading to metabolic confusion and the inability to differentiate fed from fasting conditions. This review focuses on the impact of nuclear receptors in the pathogenesis and treatment of NAFLD. Clinical trials including PIVENS and FLINT demonstrate that nuclear receptor targeted therapies may lead to the paradoxical dissociation of steatosis, inflammation, fibrosis, insulin resistance, dyslipidemia and obesity. Novel strategies currently under development (including tissue-specific ligands and dual receptor agonists) may be required to separate the beneficial effects of nuclear receptor activation from unwanted metabolic

  19. Identification and Biological Evaluation of Coactivator Binding Inhibitors for the Estrogen Receptor

    Science.gov (United States)

    Gunther, Jillian Rebecca

    2009-01-01

    The physiologic effects of estrogen action through the estrogen receptor (ER) are widespread, as this hormone exerts actions in both reproductive (e.g., uterus) and non-reproductive (e.g., bone, brain) tissues in both men and women. As such, the regulation of the activity of this ligand-activated transcription factor is highly relevant to the…

  20. Overexpression of steroid receptor coactivator-3 in bone cancers: an in vivo immunohistochemical study with tissue microarray.

    Science.gov (United States)

    Luo, Fei; Li, Wei; Zhang, Jiqiang; Huang, Ke; Fu, Jingshu; Xie, Zhao

    2013-12-01

    Bone tissue is steroid-responsive and profoundly regulated by steroids and/or their receptors. Bone cancers (either primary or metastatic) belong to the most dangerous tumors. Previous studies have demonstrated overexpression of steroid receptor coactivator-3 (SRC-3) in many cancers, such as breast cancer, prostate cancer, thyroid cancer, functioning in the regulation of cancer cell proliferation, invasion, and metastasis. However, so far, the expression and function of SRC-3 in bone cancers have not yet been clarified. In this study, nickel-intensified immunohistochemistry was conducted using a commercial tissue microarray (with 94 cases of bone cancer tissue and 10 normal bone tissues), and the 4-scoring system was employed to evaluate the expression levels of SRC-3 immunoreactivity. The results showed that in normal bone tissue, levels of SRC-3 are almost negative (score=0), the total positivity (score=1-3) of SRC-3 immunoreactivities in bone cancers was 74.47%. There were no significant differences in gender, status (malignant or benign) or (mean) age (p>0.05). The percentage of positivity was 77.78% in osteogenic tumors, 58.82% in cartilage tumors, 70% in giant cell tumors, 100% in hematopoietic tumors, 77.78% in miscellaneous lesions, and 75% in miscellaneous tumors. Age related differences of SRC-3 immunoreactivities were detected in cartilage tumors and giant cell tumors (p<0.05). The above results clearly demonstrated a high frequency of overexpression of SRC-3 immunoreactivities in different bone cancers, indicating its potential roles in the prognosis and treatment of these cancers. Copyright © 2013 Elsevier GmbH. All rights reserved.

  1. Sustained expression of steroid receptor coactivator SRC-2/TIF-2 is associated with better prognosis in malignant pleural mesothelioma.

    LENUS (Irish Health Repository)

    Jennings, Cormac J

    2012-02-01

    INTRODUCTION: Estrogen receptor beta (ERbeta) overexpression by malignant pleural mesothelioma (MPM) tumor cells correlates with enhanced patient survival. ER-regulated transcription is mediated by the p160 family of steroid receptor coactivators (SRCs), and SRC isoform overexpression is associated with worse prognosis in many steroid-related malignancies. The aim of this study was to establish whether SRC isoform expression varied between individual MPM tumors with positive or negative prognostic significance. METHODS: Immunohistochemical analysis of tumor biopsies from 89 subjects with confirmed histological diagnosis of MPM and biopsies from 3 normal control subjects was performed to detect the expression of SRC-1, SRC-2 (TIF-2), SRC-3 (AIB-1), and ERbeta. Allred scores for expression of ERbeta and each of the SRCs were determined, and Kaplan-Meier survival curves were calculated to correlate biomarker expression, gender, and histology type with postdiagnosis survival. RESULTS: ERbeta and all the SRCs were expressed at high levels in normal pleural mesothelium, and expression of each biomarker was reduced or lost in a subset of the MPM subjects; however, postdiagnosis survival only significantly correlated with TIF-2 expression. Low or intermediate expression of TIF-2 correlated with reduced median postdiagnosis survival (9 months) compared with those subjects whose tumors highly expressed TIF-2 (20 months) (p = 0.036, log-rank test). CONCLUSIONS: Maintained high expression of TIF-2 in tumor cells is a positive prognostic indicator for postdiagnosis survival in patients with confirmed MPM. This is the first clinical study to correlate high TIF-2 expression with improved patient prognosis in any malignancy.

  2. PRIC320, a transcription coactivator, isolated from peroxisome proliferator-binding protein complex.

    Science.gov (United States)

    Surapureddi, Sailesh; Viswakarma, Navin; Yu, Songtao; Guo, Dongsheng; Rao, M Sambasiva; Reddy, Janardan K

    2006-05-05

    Ciprofibrate, a potent peroxisome proliferator, induces pleiotropic responses in liver by activating peroxisome proliferator-activated receptor alpha (PPARalpha), a nuclear receptor. Transcriptional regulation by liganded nuclear receptors involves the participation of coregulators that form multiprotein complexes possibly to achieve cell and gene specific transcription. SDS-PAGE and matrix-assisted laser desorption/ionization reflection time-of-flight mass spectrometric analyses of ciprofibrate-binding proteins from liver nuclear extracts obtained using ciprofibrate-Sepharose affinity matrix resulted in the identification of a new high molecular weight nuclear receptor coactivator, which we designated PRIC320. The full-length human cDNA encoding this protein has an open-reading frame that codes for a 320kDa protein containing 2882 amino acids. PRIC320 contains five LXXLL signature motifs that mediate interaction with nuclear receptors. PRIC320 binds avidly to nuclear receptors PPARalpha, CAR, ERalpha, and RXR, but only minimally with PPARgamma. PRIC320 also interacts with transcription cofactors CBP, PRIP, and PBP. Immunoprecipitation-immunoblotting as well as cellular localization studies confirmed the interaction between PPARalpha and PRIC320. PRIC320 acts as a transcription coactivator by stimulating PPARalpha-mediated transcription. We conclude that ciprofibrate, a PPARalpha ligand, binds a multiprotein complex and PRIC320 cloned from this complex functions as a nuclear receptor coactivator.

  3. Application of Circular Dichroism Spectroscopy to the Analysis of the Interaction Between the Estrogen Receptor Alpha and Coactivators: The Case of Calmodulin.

    Science.gov (United States)

    Miclet, Emeric; Bourgoin-Voillard, Sandrine; Byrne, Cillian; Jacquot, Yves

    2016-01-01

    The estrogen receptor α ligand-binding domain (ERα-LBD) binds the natural hormone 17β-estradiol (E2) to induce transcription and cell proliferation. This process occurs with the contribution of protein and peptide partners (also called coactivators) that can modulate the structure of ERα, and therefore its specificity of action. As with most transcription factors, ERα exhibits a high content of α helix, making it difficult to routinely run spectroscopic studies capable of deciphering the secondary structure of the different partners under binding conditions. Ca(2+)-calmodulin, a protein also highly structured in α-helix, is a key coactivator for ERα activity. Here, we show how circular dichroism can be used to study the interaction of ERα with Ca(2+)-calmodulin. Our approach allows the determination not only of the conformational changes induced upon complex formation but also the dissociation constant (K d) of this interaction.

  4. Stapled Peptides with γ-Methylated Hydrocarbon Chains for the Estrogen Receptor/Coactivator Interaction.

    Science.gov (United States)

    Speltz, Thomas E; Fanning, Sean W; Mayne, Christopher G; Fowler, Colin; Tajkhorshid, Emad; Greene, Geoffrey L; Moore, Terry W

    2016-03-18

    "Stapled" peptides are typically designed to replace two non-interacting residues with a constraining, olefinic staple. To mimic interacting leucine and isoleucine residues, we have created new amino acids that incorporate a methyl group in the γ-position of the stapling amino acid S5. We have incorporated them into a sequence derived from steroid receptor coactivator 2, which interacts with estrogen receptor α. The best peptide (IC50 =89 nm) replaces isoleucine 689 with an S-γ-methyl stapled amino acid, and has significantly higher affinity than unsubstituted peptides (390 and 760 nm). Through X-ray crystallography and molecular dynamics studies, we show that the conformation taken up by the S-γ-methyl peptide minimizes the syn-pentane interactions between the α- and γ-methyl groups.

  5. Peroxisome proliferator-activated receptor-gamma abrogates Smad-dependent collagen stimulation by targeting the p300 transcriptional coactivator.

    Science.gov (United States)

    Ghosh, Asish K; Bhattacharyya, Swati; Wei, Jun; Kim, Suyeon; Barak, Yaacov; Mori, Yasuji; Varga, John

    2009-09-01

    Ligands of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) abrogate the stimulation of collagen gene transcription induced by transforming growth factor-beta (TGF-beta). Here, we delineate the mechanisms underlying this important novel physiological function for PPAR-gamma in connective tissue homeostasis. First, we demonstrated that antagonistic regulation of TGF-beta activity by PPAR-gamma ligands involves cellular PPAR-gamma, since 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)) failed to block TGF-beta-induced responses in either primary cultures of PPAR-gamma-null murine embryonic fibroblasts, or in normal human skin fibroblasts with RNAi-mediated knockdown of PPAR-gamma. Next, we examined the molecular basis underlying the abrogation of TGF-beta signaling by PPAR-gamma in normal human fibroblasts in culture. The results demonstrated that Smad-dependent transcriptional responses were blocked by PPAR-gamma without preventing Smad2/3 activation. In contrast, the interaction between activated Smad2/3 and the transcriptional coactivator and histone acetyltransferase p300 induced by TGF-beta, and the accumulation of p300 on consensus Smad-binding DNA sequences and histone H4 hyperacetylation at the COL1A2 locus, were all prevented by PPAR-gamma. Wild-type p300, but not a mutant form of p300 lacking functional histone acetyltransferase, was able to restore TGF-beta-induced stimulation of COL1A2 in the presence of PPAR-gamma ligands. Collectively, these results indicate that PPAR-gamma blocked Smad-mediated transcriptional responses by preventing p300 recruitment and histone H4 hyperacetylation, resulting in the inhibition of TGF-beta-induced collagen gene expression. Pharmacological activation of PPAR-gamma thus may represent a novel therapeutic approach to target p300-dependent TGF-beta profibrotic responses such as stimulation of collagen gene expression.

  6. Truncated peroxisome proliferator-activated receptorcoactivator 1α splice variant is severely altered in Huntington's disease.

    Science.gov (United States)

    Johri, Ashu; Starkov, Anatoly A; Chandra, Abhishek; Hennessey, Thomas; Sharma, Abhijeet; Orobello, Sara; Squitieri, Ferdinando; Yang, Lichuan; Beal, M Flint

    2011-01-01

    Reduced peroxisome proliferator-activated receptorcoactivator 1α (PGC1α) gene expression has been observed in striatal cell lines, transgenic mouse models of Huntington's disease (HD), and brain tissue from HD patients. As this protein is a key transcription regulator of the expression of many mitochondrial proteins, these observations strongly support the role of aberrant mitochondrial function in the pathogenesis of HD. The PGC1α protein undergoes posttranslational modifications that affect its transcriptional activity. The N-truncated splice variant of PGC1α (NT-PGC1α) is produced in tissues, but the role of truncated splice variants of PGC1α in HD and in the regulation of mitochondrial gene expression has not been elucidated. To examine the expression and modulation of expression of NT-PGC1α levels in HD. We found that the NT-PGC1α protein, a splice variant of ∼38 kDa, but not full-length PGC1α is severely and consistently altered in human HD brain, human HD myoblasts, mouse HD models, and HD striatal cells. NT-PGC1α levels were significantly upregulated in HD cells and mouse brown fat by physiologically relevant stimuli that are known to upregulate PGC1α gene expression. This resulted in an increase in mitochondrial gene expression and cytochrome c content. Our data suggest that NT-PGC1α is an important component of the PGC1α transcriptional network, which plays a significant role in the pathogenesis of HD. Copyright © 2011 S. Karger AG, Basel.

  7. Analyzing phosphorylation-dependent regulation of subcellular localization and transcriptional activity of transcriptional coactivator NT-PGC-1α.

    Science.gov (United States)

    Chang, Ji Suk; Gettys, Thomas W

    2013-01-01

    Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a nuclear transcriptional coactivator that regulates the genes involved in energy metabolism. Recent evidence has been provided that alternative splicing of PPARGC1A gene produces a functional but predominantly cytosolic isoform of PGC-1α (NT-PGC-1α). We have demonstrated that transcriptional coactivation capacity of NT-PGC-1α is directly correlated with its nuclear localization in a PKA phosphorylation-dependent manner. In this chapter, we describe quantitative imaging analysis methods that are developed to measure the relative fluorescence intensity of the protein of interest in the nucleus and cytoplasm in a single cell and the frequency distribution of nuclear/cytoplasmic intensity ratios in the population of cells, respectively. This chapter also describes transient cotransfection and dual-luciferase reporter gene assay that examine the ability of coactivators to activate the transcriptional activity of transcription factors.

  8. Chemical Approaches to Nuclear Receptors in Metabolism

    Science.gov (United States)

    Margolis, Ronald N.; Moore, David D.; Willson, Timothy M.; Guy, R. Kip

    2017-01-01

    The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) sponsored a workshop, “Chemical Approaches to Nuclear Receptors and Metabolism,” in April 2009 to explore how chemical and molecular biology and physiology can be exploited to further our understanding of nuclear receptor structure, function, and role in disease. Signaling cascades involving nuclear receptors are more complex and interrelated than once thought. Nuclear receptors continue to be attractive targets for drug discovery. The overall goal of this workshop was to identify gaps in our understanding of the complexity of ligand activities and begin to address them by (i) increasing the collaboration of investigators from different disciplines, (ii) developing a better understanding of chemical modulation of nuclear receptor action, and (iii) identifying opportunities and roadblocks in the path of translating basic research to discovery of new therapeutics. PMID:19654413

  9. Hepatic drug transporters and nuclear receptors: Regulation by therapeutic agents

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The canalicular membrane represents the excretory pole of hepatocytes. Bile is an important route of elimina-tion of potentially toxic endo- and xenobiotics (including drugs and toxins), mediated by the major canalicular transporters: multidrug resistance protein 1 (MDR1, ABCB1), also known as P-glycoprotein, multidrug re-sistance-associated protein 2 (MRP2, ABCC2), and the breast cancer resistance protein (BCRP, ABCG2). Their activities depend on regulation of expression and proper localization at the canalicular membrane, as regulated by transcriptional and post-transcriptional events, re-spectively. At transcriptional level, specific nuclear re-ceptors (NR)s modulated by ligands, co-activators and co-repressors, mediate the physiological requirements of these transporters. This complex system is also re-sponsible for alterations occurring in specific liver pa-thologies. We briefly describe the major Class Ⅱ NRs, pregnane X receptor (PXR) and constitutive androstane receptor (CAR), and their role in regulating expression of multidrug resistance proteins. Several therapeutic agents regulate the expression of relevant drug trans-porters through activation/inactivation of these NRs. We provide some representative examples of the action of therapeutic agents modulating liver drug transporters, which in addition, involve CAR or PXR as mediators.

  10. Metabolomic and Lipidomic Analysis of the Heart of Peroxisome Proliferator-Activated ReceptorCoactivator 1-β Knock Out Mice on a High Fat Diet

    Directory of Open Access Journals (Sweden)

    Gregor McCombie

    2012-06-01

    Full Text Available The peroxisome proliferator-activated receptorcoactivators (PGC-1 are transcriptional coactivators with an important role in mitochondrial biogenesis and regulation of genes involved in the electron transport chain and oxidative phosphorylation in oxidative tissues including cardiac tissue. These coactivators are thought to play a key role in the development of obesity, type 2 diabetes and the metabolic syndrome. In this study we have used a combined metabolomic and lipidomic analysis of cardiac tissue from the PGC-1β null mouse to examine the effects of a high fat diet on this organ. Multivariate statistics readily separated tissue from PGC-1β null mice from their wild type controls either in gender specific models or in combined datasets. This was associated with an increase in creatine and a decrease in taurine in the null mouse, and an increase in myristic acid and a reduction in long chain polyunsaturated fatty acids for both genders. The most profound changes were detected by liquid chromatography mass spectrometry analysis of intact lipids with the tissue from the null mouse having a profound increase in a number of triglycerides. The metabolomic and lipodomic changes indicate PGC-1β has a profound influence on cardiac metabolism.

  11. The Skeletal Response to Estrogen is Impaired in Female but not in Male Steroid Receptor Coactivator (SRC)-1 Knock Out Mice

    OpenAIRE

    Mödder, U. I.; Sanyal, A.; Xu, J; O’Malley, B.W.; Spelsberg, T C; Khosla, S.

    2007-01-01

    Estrogen (E) is critical for the maintenance of bone mass in both female and male mice and steroid receptor coactivator (SRC)-1 has been shown to be important for mediating E effects on bone, at least in female mice. In the present study, we defined the skeletal phenotype of male SRC-1 knock out (KO) mice and compared it with their female littermates. Further, to determine the role of SRC-1 in mediating effects of E on bone in male mice, we examined the skeletal effects of gonadectomy (gnx) w...

  12. Semenogelin I promotes prostate cancer cell growth via functioning as an androgen receptor coactivator and protecting against zinc cytotoxicity.

    Science.gov (United States)

    Ishiguro, Hitoshi; Izumi, Koji; Kashiwagi, Eiji; Zheng, Yichun; Li, Yi; Kawahara, Takashi; Miyamoto, Hiroshi

    2015-01-01

    A seminal plasma protein, semenogelin I (SgI), contributes to sperm clotting, upon binding to Zn(2+), and can be proteolyzed by prostate-specific antigen (PSA), resulting in release of the trapped spermatozoa after ejaculation. In contrast, the role of SgI in the development and progression of any types of malignancies remains largely unknown. We previously demonstrated that SgI was overexpressed in prostate cancer tissues and its expression was enhanced by zinc treatment in LNCaP cells. In the current study, using cell lines stably expressing SgI, we investigated its biological functions, in conjunction with zinc, androgen, and androgen receptor (AR), in prostate cancer. Zinc, without SgI, inhibited cell growth of both AR-positive and AR-negative lines. Co-expression of SgI prevented zinc inhibiting dihydrotestosterone-mediated proliferation of AR-positive cells, whereas SgI and/or dihydrotestosterone showed marginal effects in AR-negative cells. Similar effects of SgI overexpression in LNCaP on dihydrotestosterone-induced cell invasion, such as its significant enhancement with zinc, were seen. Overexpression of SgI in LNCaP and CWR22Rv1 cells also augmented dihydrotestosterone-mediated PSA expression (mRNA, protein) in the presence of zinc. However, culture in the conditioned medium containing secreted forms of SgI failed to significantly increase cell viability with or without zinc. In luciferase reporter gene assays, SgI showed even slight inhibitory effects (8% and 15% decreases in PC3 and CWR22Rv1, respectively) at 0 μM zinc and significant stimulatory effects (2.1- and 3.2-fold) at 100 μM zinc on dihydrotestosterone-enhanced AR transactivation. Co-immunoprecipitation then demonstrated dihydrotestosterone-induced physical interactions between AR and SgI. These results suggest that intracellular SgI, together with zinc, functions as an AR coactivator and thereby promotes androgen-mediated prostate cancer progression.

  13. Coactivator Recruitment of AhR/ARNT1

    Directory of Open Access Journals (Sweden)

    Alexander Endler

    2014-06-01

    Full Text Available A common feature of nuclear receptors (NRs is the transformation of external cell signals into specific transcriptions of the signal molecule. Signal molecules function as ligands for NRs and, after their uptake, activated NRs form homo- or heterodimers at promoter recognition sequences of the specific genes in the nucleus. Another common feature of NRs is their dependence on coactivators, which bridge the basic transcriptional machinery and other cofactors to the target genes, in order to initiate transcription and to unwind histone-bound DNA for exposing additional promoter recognition sites via their histone acetyltransferase (HAT function. In this review, we focus on our recent findings related to the recruitment of steroid receptor coactivator 1 (SRC1/NCoA1 by the estrogen receptor-α (ERα and by the arylhydrocarbon receptor/arylhydrocarbon receptor nuclear translocator 1 (AhR/ARNT1 complex. We also describe the extension of our previously published findings regarding the binding between ARNT1.1 exon16 and SRC1e exon 21, via in silico analyses of androgen receptor (AR NH2-carboxyl-terminal interactions, the results of which were verified by in vitro experiments. Based on these data, we suggest a newly derived tentative binding site of nuclear coactivator 2/glucocorticoid receptor interacting protein-1/transcriptional intermediary factor 2 (NCOA-2/ GRIP-1/TIF-2 for ARNT1.1 exon 16. Furthermore, results obtained by immunoprecipitation have revealed a second leucine-rich binding site for hARNT1.1 exon 16 in SRC1e exon 21 (LSSTDLL. Finally, we discuss the role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD as an endocrine disruptor for estrogen related transcription.

  14. Brain nuclear receptors and body weight regulation

    Science.gov (United States)

    Neural pathways, especially those in the hypothalamus, integrate multiple nutritional, hormonal, and neural signals, resulting in the coordinated control of body weight balance and glucose homeostasis. Nuclear receptors (NRs) sense changing levels of nutrients and hormones, and therefore play essent...

  15. Nuclear progesterone receptor isoforms and their functions in the female reproductive tract.

    Science.gov (United States)

    Rekawiecki, R; Kowalik, M K; Kotwica, J

    2011-01-01

    Progesterone (P4), which is produced by the corpus luteum (CL), creates proper conditions for the embryo implantation, its development, and ensures proper conditions for the duration of pregnancy. Besides the non-genomic activity of P4 on target cells, its main physiological effect is caused through genomic action by the progesterone nuclear receptor (PGR). This nuclear progesterone receptor occurs in two specific isoforms, PGRA and PGRB. PGRA isoform acts as an inhibitor of transcriptional action of PGRB. The inactive receptor is connected with chaperone proteins and attachment of P4 causes disconnection of chaperones and unveiling of DNA binding domain (DBD). After receptor dimerization in the cells' nucleus and interaction with hormone response element (HRE), the receptor coactivators are connected and transcription is initiated. The ratio of these isoforms changes during the estrous cycle and reflects the different levels of P4 effect on the reproductive system. Both isoforms, PGRA and PGRB, also show a different response to the P4 receptor antagonist activity. Connection of the antagonist to PGRA can block PGRB, but acting through the PGRB isoform, P4 receptor antagonist may undergo conversion to a strongly receptor agonist. A third isoform, PGRC, has also been revealed. This isoform is the shortest and does not have transcriptional activity. Alternative splicing and insertion of additional exons may lead to the formation of different PGR isoforms. This paper summarizes the available data on the progesterone receptor isoforms and its regulatory action within the female reproductive system.

  16. Crystallographic Identification and Functional Characterization of Phospholipids as Ligands for the Orphan Nuclear Receptor Steroidogenic Factor-1

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong; Choi, Mihwa; Cavey, Greg; Daugherty, Jennifer; Suino, Kelly; Kovach, Amanda; Bingham, Nathan C.; Kliewer, Steven A.; Xu, H.Eric (Van Andel); (U. of Texas-SMED)

    2010-11-10

    The orphan nuclear receptor steroidogenic factor 1 (SF-1) regulates the differentiation and function of endocrine glands. Although SF-1 is constitutively active in cell-based assays, it is not known whether this transcriptional activity is modulated by ligands. Here, we describe the 1.5 {angstrom} crystal structure of the SF-1 ligand binding domain in complex with an LXXLL motif from a coregulator protein. The structure reveals the presence of a phospholipid ligand in a surprisingly large pocket ({approx}1600 {angstrom}{sup 3}), with the receptor adopting the canonical active conformation. The bound phospholipid is readily exchanged and modulates SF-1 interactions with coactivators. Mutations designed to reduce the size of the SF-1 pocket or to disrupt hydrogen bonds with the phospholipid abolish SF-1/coactivator interactions and significantly reduce SF-1 transcriptional activity. These findings provide evidence that SF-1 is regulated by endogenous ligands and suggest an unexpected relationship between phospholipids and endocrine development and function.

  17. Peroxisome proliferator-activated receptor-gamma coactivator-1alpha activation of CYP7A1 during food restriction and diabetes is still inhibited by small heterodimer partner.

    Science.gov (United States)

    Shin, Dong-Ju; Osborne, Timothy F

    2008-05-30

    Cholesterol 7alpha-hydroxylase (CYP7A1) catalyzes the rate-limiting step in the classic pathway of hepatic bile acid biosynthesis from cholesterol. During fasting and in type I diabetes, elevated levels of peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1alpha) induce expression of the Cyp7A1 gene and overexpression of PGC-1alpha in hepatoma cells stimulates bile acid synthesis. Using Ad-PGC-1alpha-RNA interference to induce acute disruption of PGC-1alpha in mice, here we show that PGC-1alpha is necessary for fasting-mediated induction of CYP7A1. Co-immunoprecipitation and promoter activation studies reveal that the induction of CYP7A1 is mediated by direct interaction between PGC-1alpha and the AF2 domain of liver receptor homolog-1 (LRH-1). In contrast, the very similar PGC-1beta could not substitute for PGC-1alpha. We also show that transactivation of PGC-1alpha and LRH-1 is repressed by the small heterodimer partner (SHP). Treatment of mice with GW4064, a synthetic agonist for farnesoid X receptor, induced SHP expression and decreased both the recruitment of PGC-1alpha to the Cyp7A1 promoter and the fasting-induced expression of CYP7A1 mRNA. These data suggest that PGC-1alpha is an important co-activator for LRH-1 and that SHP targets the interaction between LRH-1 and PGC-1alpha to inhibit CYP7A1 expression. Overall, these studies provide further evidence for the important role of PGC-1alpha in bile acid homeostasis and suggest that pharmacological targeting of farnesoid X receptor in vivo can be used to reverse the increase in CYP7A1 associated with adverse metabolic conditions.

  18. Neuromodulatory effect of Gαs- or Gαq-coupled G-protein-coupled receptor on NMDA receptor selectively activates the NMDA receptor/Ca2+/calcineurin/cAMP response element-binding protein-regulated transcriptional coactivator 1 pathway to effectively induce brain-derived neurotrophic factor expression in neurons.

    Science.gov (United States)

    Fukuchi, Mamoru; Tabuchi, Akiko; Kuwana, Yuki; Watanabe, Shinjiro; Inoue, Minami; Takasaki, Ichiro; Izumi, Hironori; Tanaka, Ayumi; Inoue, Ran; Mori, Hisashi; Komatsu, Hidetoshi; Takemori, Hiroshi; Okuno, Hiroyuki; Bito, Haruhiko; Tsuda, Masaaki

    2015-04-01

    Although coordinated molecular signaling through excitatory and modulatory neurotransmissions is critical for the induction of immediate early genes (IEGs), which lead to effective changes in synaptic plasticity, the intracellular mechanisms responsible remain obscure. Here we measured the expression of IEGs and used bioluminescence imaging to visualize the expression of Bdnf when GPCRs, major neuromodulator receptors, were stimulated. Stimulation of pituitary adenylate cyclase-activating polypeptide (PACAP)-specific receptor (PAC1), a Gαs/q-protein-coupled GPCR, with PACAP selectively activated the calcineurin (CN) pathway that is controlled by calcium signals evoked via NMDAR. This signaling pathway then induced the expression of Bdnf and CN-dependent IEGs through the nuclear translocation of CREB-regulated transcriptional coactivator 1 (CRTC1). Intracerebroventricular injection of PACAP and intraperitoneal administration of MK801 in mice demonstrated that functional interactions between PAC1 and NMDAR induced the expression of Bdnf in the brain. Coactivation of NMDAR and PAC1 synergistically induced the expression of Bdnf attributable to selective activation of the CN pathway. This CN pathway-controlled expression of Bdnf was also induced by stimulating other Gαs- or Gαq-coupled GPCRs, such as dopamine D1, adrenaline β, CRF, and neurotensin receptors, either with their cognate agonists or by direct stimulation of the protein kinase A (PKA)/PKC pathway with chemical activators. Thus, the GPCR-induced expression of IEGs in coordination with NMDAR might occur via the selective activation of the CN/CRTC1/CREB pathway under simultaneous excitatory and modulatory synaptic transmissions in neurons if either the Gαs/adenylate cyclase/PKA or Gαq/PLC/PKC-mediated pathway is activated.

  19. Knockdown of peroxisome proliferator-activated receptor gamma coactivator-1 alpha increased apoptosis of human endometrial cancer HEC-1A cells

    Directory of Open Access Journals (Sweden)

    Yang H

    2016-08-01

    Full Text Available Hui Yang, Rui Yang, Hao Liu, Zhongqian Ren, Cuicui Wang, Da Li, Xiaoxin Ma Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, People’s Republic of China Background: Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α coactivates multiple transcription factors and regulates several metabolic processes. In this study, we focused on the roles of PGC-1α in the apoptosis of endometrial cancer HEC-1A cells. Materials and methods: PGC-1α expression in the HEC-1A cells was detected with real-time polymerase chain reaction and Western blot. Small interfering RNA directed against PGC-1α was designed and synthesized, and RNA interference technology was used to knock down PGC-1α mRNA and protein expression. Cell apoptosis, cell cycle, and mitochondrial membrane potential were then analyzed using flow cytometry. The expression of apoptotic proteins, Bcl-2 and Bax, was detected with Western blot. Results: The specific downregulation of PGC-1α expression in the HEC-1A cells increased their apoptosis through the mitochondrial apoptotic pathway by reducing the expression of Bcl-2 and increasing the expression of Bax. Conclusion: These results suggest that PGC-1α influences the apoptosis of HEC-1A cells and also provides a molecular basis for further investigation of the apoptotic mechanism in human endometrial cancer. Keywords: endometrial cancer, PGC-1α, apoptosis, Bcl-2, Bax

  20. Activation of peroxisome proliferator-activated receptorcoactivator 1α ameliorates mitochondrial dysfunction and protects podocytes from aldosterone-induced injury.

    Science.gov (United States)

    Yuan, Yanggang; Huang, Songming; Wang, Wenyan; Wang, Yingying; Zhang, Ping; Zhu, Chunhua; Ding, Guixia; Liu, Bicheng; Yang, Tianxin; Zhang, Aihua

    2012-10-01

    Glomerular podocytes are highly specialized epithelial cells whose injury in glomerular diseases causes proteinuria. Since mitochondrial dysfunction is an early event in podocyte injury, we tested whether a major regulator of oxidative metabolism and mitochondrial function, the transcriptional coactivator peroxisome proliferator-activated receptorcoactivator 1α (PGC-1α), affects podocyte damage. Aldosterone-induced injury decreased PGC-1α expression, and induced mitochondrial and podocyte damage in dose- and time-dependent manners. The suppression of endogenous PGC-1α by RNAi caused podocyte mitochondrial damage and apoptosis while its increase by infection with an adenoviral vector prevented aldosterone-induced mitochondrial malfunction and inhibited injury. Overexpression of the silent mating type information regulation 2 homolog 1, a gene upstream of PGC-1α, prevented aldosterone-induced mitochondrial damage and podocyte injury by upregulating PGC-1α at both the transcriptional and post-translational levels. Resveratrol, a SIRT1 activator, attenuated aldosterone-induced mitochondrial malfunction and podocyte injury in vitro and in aldosterone-infused mice in vivo. Hence, endogenous PGC-1α may be important for maintenance of mitochondrial function in podocytes under normal conditions. Activators of SIRT1, such as resveratol, may be therapeutically useful in glomerular diseases to promote and maintain PGC-1α expression and, consequently, podocyte integrity.

  1. Estrogen-Related Receptor alpha (ERR (alpha))-Coactivator Interactions as Targets for Discovery of New Anti-Breast Cancer Therapeutics

    Science.gov (United States)

    2007-03-01

    Lu c. A ct . ( re l. to T AT A- lu c) A. pTATA-Luc pERE(5x)-Luc pERRE (5x)-Luc - - - Figure 3. GRIP1 is a specific coactivator of “activated” ERRα...AGGTCACAGTGACCT-3’) upstream of the firefly luciferase reporter gene. pERRE (5x)-Luc contains five copies of the consensus estrogen-related receptor response...7 7- 42 3 ER R α 1 ER R α 1 7 7- 42 3 pTATA-Luc pERE(5x)-Luc pERRE (5x)-Luc Expression plasmid: Reporter: ER R α 1 ER R α 1 7 7- 42 3- - - B. 12

  2. The roles of nuclear receptors CAR and PXR in hepatic energy metabolism.

    Science.gov (United States)

    Konno, Yoshihiro; Negishi, Masahiko; Kodama, Susumu

    2008-01-01

    Nuclear receptors constitutive active/androstane receptor (CAR) and pregnane X receptor (PXR) were originally characterized as transcription factors regulating the hepatic genes that encode drug metabolizing enzymes. Recent works have now revealed that these nuclear receptors also play the critical roles in modulating hepatic energy metabolism. While CAR and PXR directly bind to their response sequences phenobarbital-responsive enhancer module (PBREM) and xenobiotic responsive enhancer module (XREM) in the promoter of target genes to increase drug metabolism, the receptors also cross talk with various hormone responsive transcription factors such as forkhead box O1 (FoxO1), forkhead box A2 (FoxA2), cAMP-response element binding protein, and peroxisome proliferator activated receptor gamma coactivator 1alpha (PGC 1alpha) to decrease energy metabolism through down-regulating gluconeogenesis, fatty acid oxidation and ketogenesis and up-regulating lipogenesis. In addition, CAR modulates thyroid hormone activity by regulating type 1 deiodinase in the regenerating liver. Thus, CAR and PXR are now placed at the crossroad where both xenobiotics and endogenous stimuli co-regulate liver function.

  3. Phenobarbital Meets Phosphorylation of Nuclear Receptors.

    Science.gov (United States)

    Negishi, Masahiko

    2017-05-01

    Phenobarbital was the first therapeutic drug to be characterized for its induction of hepatic drug metabolism. Essentially at the same time, cytochrome P450, an enzyme that metabolizes drugs, was discovered. After nearly 50 years of investigation, the molecular target of phenobarbital induction has now been delineated to phosphorylation at threonine 38 of the constitutive androstane receptor (NR1I3), a member of the nuclear receptor superfamily. Determining this mechanism has provided us with the molecular basis to understand drug induction of drug metabolism and disposition. Threonine 38 is conserved as a phosphorylation motif in the majority of both mouse and human nuclear receptors, providing us with an opportunity to integrate diverse functions of nuclear receptors. Here, I review the works and accomplishments of my laboratory at the National Institutes of Health National Institute of Environmental Health Sciences and the future research directions of where our study of the constitutive androstane receptor might take us. U.S. Government work not protected by U.S. copyright.

  4. Rosiglitazone-induced mitochondrial biogenesis in white adipose tissue is independent of peroxisome proliferator-activated receptor γ coactivator-1α.

    Directory of Open Access Journals (Sweden)

    Rosario Pardo

    Full Text Available BACKGROUND: Thiazolidinediones, a family of insulin-sensitizing drugs commonly used to treat type 2 diabetes, are thought to exert their effects in part by promoting mitochondrial biogenesis in white adipose tissue through the transcriptional coactivator PGC-1α (Peroxisome Proliferator-Activated Receptor γ Coactivator-1α. METHODOLOGY/PRINCIPAL FINDINGS: To assess the role of PGC-1α in the control of rosiglitazone-induced mitochondrial biogenesis, we have generated a mouse model that lacks expression of PGC-1α specifically in adipose tissues (PGC-1α-FAT-KO mice. We found that expression of genes encoding for mitochondrial proteins involved in oxidative phosphorylation, tricarboxylic acid cycle or fatty acid oxidation, was similar in white adipose tissue of wild type and PGC-1α-FAT-KO mice. Furthermore, the absence of PGC-1α did not prevent the positive effect of rosiglitazone on mitochondrial gene expression or biogenesis, but it precluded the induction by rosiglitazone of UCP1 and other brown fat-specific genes in white adipose tissue. Consistent with the in vivo findings, basal and rosiglitazone-induced mitochondrial gene expression in 3T3-L1 adipocytes was unaffected by the knockdown of PGC-1α but it was impaired when PGC-1β expression was knockdown by the use of specific siRNA. CONCLUSIONS/SIGNIFICANCE: These results indicate that in white adipose tissue PGC-1α is dispensable for basal and rosiglitazone-induced mitochondrial biogenesis but required for the rosiglitazone-induced expression of UCP1 and other brown adipocyte-specific markers. Our study suggests that PGC-1α is important for the appearance of brown adipocytes in white adipose tissue. Our findings also provide evidence that PGC-1β and not PGC-1α regulates basal and rosiglitazone-induced mitochondrial gene expression in white adipocytes.

  5. Requirement for the endocannabinoid system in social interaction impairment induced by coactivation of dopamine D1 and D2 receptors in the piriform cortex.

    Science.gov (United States)

    Zenko, Michelle; Zhu, Yongyong; Dremencov, Eliyahu; Ren, Wei; Xu, Lin; Zhang, Xia

    2011-08-01

    The dopamine receptor family consists of D1-D5 receptors (D1R-D5R), and we explored the contributions of each dopamine receptor subtype in the piriform cortex (PirC) to social interaction impairment (SII). Rats received behavioral tests or electrophysiological recording of PirC neuronal activity after injection of the D1R/D5R agonist SKF38393, the D2R/D3R/D4R agonist quinpirole, or both, with or without pretreatment with dopamine receptor antagonists, D1R or D5R antisense oligonucleotides, the cannabinoid CB1 receptor antagonist AM281, or the endocannabinoid transporter inhibitor VDM11. Systemic injection of SKF38393 and quinpirole together, but not each one alone, induced SII and increased PirC firing rate, which were blocked by D1R or D2R antagonist. Intra-PirC microinfusion of SKF38393 and quinpirole together, but not each one alone, also induced SII, which was blocked by D1R antisense oligonucleotides or D2R antagonist but not by D3R or D4R antagonist or D5R antisense oligonucleotides. SII induced by intra-PirC SKF38393/quinpirole was blocked by AM281 and enhanced by VDM11, whereas neither AM281 nor VDM11 alone affected social interaction behavior. Coadministration of SKF38393 and quinpirole produced anxiolytic effects without significant effects on locomotor activity, olfaction, and acquisition of olfactory short-term memory. These findings suggest that SII induced by coactivation of PirC D1R and D2R requires the endocannabinoid system.

  6. Differential gene regulation by the SRC family of coactivators

    Institute of Scientific and Technical Information of China (English)

    HuaZhang; XiaYi; Xiaojingsun; NaYin; BinShi; HuijianWu; DanWang; GeWu; YongfengShang

    2005-01-01

    SRCs (steroid receptor coactivatorsl are required for nuclear receptor-mediated transcription and are also implicated in the transcription initiation by other transcription factors, such as STATs and NFKB. Despite phenotypic manifestations in gene knockout mice for SRC-1, GRIP1, and AIB1 of the SRC (Steroid Receptor Coactivator) family indicating their differential roles in animal physiology, there is no clear evidence, at the molecular level, to support a functional specificity for these proteins. We demonstrated in this report that two species of SRC coactivators, either as AIBI:GRIP1 or as AIBI:SRC-1 are recruited, possibly through heterodimerization, on the promoter of genes that contain a classical hormone responsive element (HRE). In contrast, on non-HRE-containing gene promoters, on which steroid receptors bind indirectly, either GRIP1 orSRC-1 is recruited as a monomer, depending on the cellular abundance of the protein. Typically, non-HRE-containing genes are early genes activated by steroid receptors, whereas HRE-containing genes are activated later. Our results also showed that SRC proteins contribute to the temporal regulation of gene transcription. In addition, our experiments revealed a positive correlation between AIB1/c-myc overexpression in ER+ breast carcinoma samples, suggesting a possible mechanism for AIB1/n breast cancer carcinogenesis.

  7. Aqueous Extract of Paris polyphylla (AEPP Inhibits Ovarian Cancer via Suppression of Peroxisome Proliferator-Activated Receptor-Gamma Coactivator (PGC-1alpha

    Directory of Open Access Journals (Sweden)

    Chia-Woei Wang

    2016-06-01

    Full Text Available Chemotherapy, a major approach was used in carcinoma treatment, always involves the development of drug resistance as well as side-effects that affect the quality of patients’ lives. An association between epithelial-mesenchymal transition (EMT and chemotherapy resistance was established recently. We demonstrate in this paper that the aqueous extract of Paris polyphylla (AEPP—a traditional Chinese medicine—can be used in various cancer types for suppression of carcinogenesis. We evaluated the suppressions of EMT and mitochondrial activity by AEPP treatment in a high-glucose (HG induced-human ovarian carcinoma cell line (OVCAR-3 cells. The mitochondrial morphology was investigated using MitoTracker Deep Red FM staining. Our results indicated that AEPP reduced the viability of OVCAR-3 cells considerably through induction of apoptosis. However, this inhibitory potential of AEPP was attenuated by HG induction in OVCAR-3 cells. The levels of estrogen-related receptor (ERR-alpha activator and peroxisome proliferator-activated receptor-gamma coactivator (PGC-1alpha were elevated by HG induction, but were suppressed by AEPP treatment. Down-regulations of cell survival and EMT were oberved in OVCAR-3 cells through suppression of PGC-1alpha by AEPP treatment. These results were confirmed through PGC-1alpha knockdown and overexpression in OVCAR-3 cells. Thus, AEPP can be beneficial for treating ovarian cancer and has potential for development of an integrative cancer therapy against ovarian cancer proliferation, metastasis, and migration.

  8. Med1 subunit of the mediator complex in nuclear receptor-regulated energy metabolism, liver regeneration, and hepatocarcinogenesis.

    Science.gov (United States)

    Jia, Yuzhi; Viswakarma, Navin; Reddy, Janardan K

    2014-01-01

    Several nuclear receptors regulate diverse metabolic functions that impact on critical biological processes, such as development, differentiation, cellular regeneration, and neoplastic conversion. In the liver, some members of the nuclear receptor family, such as peroxisome proliferator-activated receptors (PPARs), constitutive androstane receptor (CAR), farnesoid X receptor (FXR), liver X receptor (LXR), pregnane X receptor (PXR), glucocorticoid receptor (GR), and others, regulate energy homeostasis, the formation and excretion of bile acids, and detoxification of xenobiotics. Excess energy burning resulting from increases in fatty acid oxidation systems in liver generates reactive oxygen species, and the resulting oxidative damage influences liver regeneration and liver tumor development. These nuclear receptors are important sensors of exogenous activators as well as receptor-specific endogenous ligands. In this regard, gene knockout mouse models revealed that some lipid-metabolizing enzymes generate PPARα-activating ligands, while others such as ACOX1 (fatty acyl-CoA oxidase1) inactivate these endogenous PPARα activators. In the absence of ACOX1, the unmetabolized ACOX1 substrates cause sustained activation of PPARα, and the resulting increase in energy burning leads to hepatocarcinogenesis. Ligand-activated nuclear receptors recruit the multisubunit Mediator complex for RNA polymerase II-dependent gene transcription. Evidence indicates that the Med1 subunit of the Mediator is essential for PPARα, PPARγ, CAR, and GR signaling in liver. Med1 null hepatocytes fail to respond to PPARα activators in that these cells do not show induction of peroxisome proliferation and increases in fatty acid oxidation enzymes. Med1-deficient hepatocytes show no increase in cell proliferation and do not give rise to liver tumors. Identification of nuclear receptor-specific coactivators and Mediator subunits should further our understanding of the complexities of metabolic

  9. Nuclear receptor 5A (NR5A) family regulates 5-aminolevulinic acid synthase 1 (ALAS1) gene expression in steroidogenic cells.

    Science.gov (United States)

    Ju, Yunfeng; Mizutani, Tetsuya; Imamichi, Yoshitaka; Yazawa, Takashi; Matsumura, Takehiro; Kawabe, Shinya; Kanno, Masafumi; Umezawa, Akihiro; Kangawa, Kenji; Miyamoto, Kaoru

    2012-11-01

    5-Aminolevulinic acid synthase 1 (ALAS1) is a rate-limiting enzyme for heme biosynthesis in mammals. Heme is essential for the catalytic activities of P450 enzymes including steroid metabolic enzymes. Nuclear receptor 5A (NR5A) family proteins, steroidogenic factor-1 (SF-1), and liver receptor homolog-1 (LRH-1) play pivotal roles in regulation of steroidogenic enzymes. Recently, we showed that expression of SF-1/LRH-1 induces differentiation of mesenchymal stem cells into steroidogenic cells. In this study, genome-wide analysis revealed that ALAS1 was a novel SF-1-target gene in differentiated mesenchymal stem cells. Chromatin immunoprecipitation and reporter assays revealed that SF-1/LRH-1 up-regulated ALAS1 gene transcription in steroidogenic cells via binding to a 3.5-kb upstream region of ALAS1. The ALAS1 gene was up-regulated by overexpression of SF-1/LRH-1 in steroidogenic cells and down-regulated by knockdown of SF-1 in these cells. Peroxisome proliferator-activated receptorcoactivator-1α, a coactivator of nuclear receptors, also strongly coactivated expression of NR5A-target genes. Reporter analysis revealed that peroxisome proliferator-activated receptorcoactivator-1α strongly augmented ALAS1 gene transcription caused by SF-1 binding to the 3.5-kb upstream region. Finally knockdown of ALAS1 resulted in reduced progesterone production by steroidogenic cells. These results indicate that ALAS1 is a novel NR5A-target gene and participates in steroid hormone production.

  10. The LIM domain protein FHL2 interacts with the NR5A family of nuclear receptors and CREB to activate the inhibin-α subunit gene in ovarian granulosa cells.

    Science.gov (United States)

    Matulis, Christina K; Mayo, Kelly E

    2012-08-01

    Nuclear receptor transcriptional activity is enhanced by interaction with coactivators. The highly related nuclear receptor 5A (NR5A) subfamily members liver receptor homolog 1 and steroidogenic factor 1 bind to and activate several of the same genes, many of which are important for reproductive function. To better understand transcriptional activation by these nuclear receptors, we sought to identify interacting proteins that might function as coactivators. The LIM domain protein four and a half LIM domain 2 (FHL2) was identified as interacting with the NR5A receptors in a yeast two-hybrid screen of a human ovary cDNA library. FHL2, and the closely related FHL1, are both expressed in the rodent ovary and in granulosa cells. Small interfering RNA-mediated knockdown of FHL1 and FHL2 in primary mouse granulosa cells reduced expression of the NR5A target genes encoding inhibin-α and P450scc. In vitro assays confirmed the interaction between the FHL and NR5A proteins and revealed that a single LIM domain of FHL2 is sufficient for this interaction, whereas determinants in both the ligand binding domain and DNA binding domain of NR5A proteins are important. FHL2 enhances the ability of both liver receptor homolog 1 and steroidogenic factor 1 to activate the inhibin-α subunit gene promoter in granulosa cells and thus functions as a transcriptional coactivator. FHL2 also interacts with cAMP response element-binding protein and substantially augments activation of inhibin gene expression by the combination of NR5A receptors and forskolin, suggesting that FHL2 may facilitate integration of these two signals. Collectively these results identify FHL2 as a novel coactivator of NR5A nuclear receptors in ovarian granulosa cells and suggest its involvement in regulating target genes important for mammalian reproduction.

  11. The asymmetric binding of PGC-1α to the ERRα and ERRγ nuclear receptor homodimers involves a similar recognition mechanism.

    Directory of Open Access Journals (Sweden)

    Maria Takacs

    Full Text Available BACKGROUND: PGC-1α is a crucial regulator of cellular metabolism and energy homeostasis that functionally acts together with the estrogen-related receptors (ERRα and ERRγ in the regulation of mitochondrial and metabolic gene networks. Dimerization of the ERRs is a pre-requisite for interactions with PGC-1α and other coactivators, eventually leading to transactivation. It was suggested recently (Devarakonda et al that PGC-1α binds in a strikingly different manner to ERRγ ligand-binding domains (LBDs compared to its mode of binding to ERRα and other nuclear receptors (NRs, where it interacts directly with the two ERRγ homodimer subunits. METHODS/PRINCIPAL FINDINGS: Here, we show that PGC-1α receptor interacting domain (RID binds in an almost identical manner to ERRα and ERRγ homodimers. Microscale thermophoresis demonstrated that the interactions between PGC-1α RID and ERR LBDs involve a single receptor subunit through high-affinity, ERR-specific L3 and low-affinity L2 interactions. NMR studies further defined the limits of PGC-1α RID that interacts with ERRs. Consistent with these findings, the solution structures of PGC-1α/ERRα LBDs and PGC-1α/ERRγ LBDs complexes share an identical architecture with an asymmetric binding of PGC-1α to homodimeric ERR. CONCLUSIONS/SIGNIFICANCE: These studies provide the molecular determinants for the specificity of interactions between PGC-1α and the ERRs, whereby negative cooperativity prevails in the binding of the coactivators to these receptors. Our work indicates that allosteric regulation may be a general mechanism controlling the binding of the coactivators to homodimers.

  12. A Gly482Ser missense mutation in the peroxisome proliferator-activated receptor gamma coactivator-1 is associated with altered lipid oxidation and early insulin secretion in Pima Indians

    DEFF Research Database (Denmark)

    Muller, Yunhua Li; Bogardus, Clifton; Pedersen, Oluf

    2003-01-01

    Peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) is a transcriptional coactivator of peroxisome proliferator-activated receptor gamma and alpha, which play important roles in adipogenesis and lipid metabolism. A single nucleotide polymorphism within the coding region...... Indians. There was no association of the Gly482Ser polymorphism with either type 2 diabetes or BMI (n = 984). However, among nondiabetic Pima Indians (n = 183-201), those with the Gly/Gly genotype had a lower mean insulin secretory response to intravenous and oral glucose and a lower mean rate of lipid...... oxidation (over 24 h in a respiratory chamber) despite a larger mean subcutaneous abdominal adipocyte size and a higher mean plasma free fatty acid concentration. These data indicate that the Gly482Ser missense polymorphism in PGC-1 has metabolic consequences on lipid metabolism that could influence insulin...

  13. 过氧化物酶体增生激活受体γ协同刺激因子-1α的研究进展%Advance in the study of peroxisome proliferator-activated receptorcoactivator

    Institute of Scientific and Technical Information of China (English)

    于波海; 滕旭

    2014-01-01

    The peroxisome proliferator-activated receptor (PPAR) γ coactivator 1-α (PGC-1α) is a transcriptional coactivator that regulates many aspects of oxidative metabolism involving in mitochondrial biogenesis and the maintaince of the integrity of mitochondrial structure through the coactivation of many nuclear receptors and transcriptional factors.PGC-1 α may play a role in the regulation of gene expression for energetic metabolism and the homeostasis of energy and nutrition.Recent studies on abnormal expression of PGC-1α have revealed significant association between this molecular and the clinical disorders,such as metabolic diseases,tumors,viral infection and inflammation.The biological activities of PGC-1 α and the association with the potential diseases has become the new research focus and this strategy could be a novel target for drug development.%过氧化物酶体增生激活受体γ(PPARγ)协同刺激因子-1α(PGC-1α)是近年来发现的一种核转录辅激活因子,能通过与核受体和转录因子相互作用调节线粒体氧化代谢过程,调控线粒体生物合成,维持线粒体结构与功能的完整性;调节能量代谢过程中的基因表达、调控能量与营养平衡.近期研究显示它与代谢疾病、病毒感染、炎症反应、肿瘤的发生、发展密切相关.通过调节PGC-1α生理功能来治疗疾病和研发药物已成为研究热点.

  14. Nuclear Receptor Signaling: a home for nuclear receptor and coregulator signaling research.

    Science.gov (United States)

    McKenna, Neil J; Evans, Ronald M; O'Malley, Bert W

    2014-01-01

    The field of nuclear receptor and coregulator signaling has grown into one of the most active and interdisciplinary in eukaryotic biology. Papers in this field are spread widely across a vast number of journals, which complicates the task of investigators in keeping current with the literature in the field. In 2003, we launched Nuclear Receptor Signaling as an Open Access reviews, perspectives and methods journal for the nuclear receptor signaling field. Building on its success and impact on the community, we have added primary research and dataset articles to this list of article categories, and we now announce the re-launch of the journal this month. Here we will summarize the rationale that informed the creation and expansion of the journal, and discuss the possibilities for its future development.

  15. Increased hepatic peroxisome proliferator-activated receptor coactivator-1α expression precedes the development of insulin resistance in offspring of rats from severe hyperglycemic mothers

    Institute of Scientific and Technical Information of China (English)

    MA Jing-mei; ZENG Chan-juan; ZHANG Li; SHOU Chong; YANG Hui-xia

    2012-01-01

    Background Prenatal hyperglycaemia may increase metabolic syndrome susceptibility of the offspring.An underlying component of the development of these morbidities is hepatic gluconeogenic molecular dysfunction.We hypothesized that maternal hyperglycaemia will influence her offsprings hepatic peroxisome proliferator-activated receptor coactivator-1α (PGC-1α) expression,a key regulator of glucose production in hepatocytes.@@Method We established maternal hyperglycaemia by streptozotocin injection to induce the maternal hyperglycaemic Wistar rat model.Offspring from the severe hyperglycemia group (SDO) and control group (CO) were monitored until 180 days after birth.Blood pressure,lipid metabolism indicators and insulin resistance (IR) were measured.Hepatic PGC-1α expression was analyzed by reverse transcription polymerase chain reaction and Western blotting.mRNA expression of two key enzymes in gluconeogenesis,glucose-6-phospha-tase (G-6-Pase) and phosphoenolpyruvate carboxykinase (PEPCK),were analyzed and compared.@@Results In the SDO group,PGC-1α expression at protein and mRNA levels were increased,so were expression of G-6-Pase and PEPCK (P<0.05).The above effects were seen prior to the onset of IR.@@Conclusion The hepatic gluconeogenic molecular dysfunction may contribute to the metabolic morbidities experienced by this population.

  16. Skeletal muscle Heat shock protein 60 increases after endurance training and induces peroxisome proliferator-activated receptor gamma coactivator 1 α1 expression.

    Science.gov (United States)

    Barone, Rosario; Macaluso, Filippo; Sangiorgi, Claudia; Campanella, Claudia; Marino Gammazza, Antonella; Moresi, Viviana; Coletti, Dario; Conway de Macario, Everly; Macario, Alberto Jl; Cappello, Francesco; Adamo, Sergio; Farina, Felicia; Zummo, Giovanni; Di Felice, Valentina

    2016-01-27

    Heat shock protein 60 (Hsp60) is a chaperone localizing in skeletal muscle mitochondria, whose role is poorly understood. In the present study, the levels of Hsp60 in fibres of the entire posterior group of hindlimb muscles (gastrocnemius, soleus, and plantaris) were evaluated in mice after completing a 6-week endurance training program. The correlation between Hsp60 levels and the expression of four isoforms of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) were investigated only in soleus. Short-term overexpression of hsp60, achieved by in vitro plasmid transfection, was then performed to determine whether this chaperone could have a role in the activation of the expression levels of PGC1α isoforms. The levels of Hsp60 protein were fibre-type specific in the posterior muscles and endurance training increased its content in type I muscle fibers. Concomitantly with the increased levels of Hsp60 released in the blood stream of trained mice, mitochondrial copy number and the expression of three isoforms of PGC1α increased. Overexpressing hsp60 in cultured myoblasts induced only the expression of PGC1 1α, suggesting a correlation between Hsp60 overexpression and PGC1 1 α activation.

  17. Peroxisome proliferator activator receptor gamma coactivator-1alpha (PGC-1α improves motor performance and survival in a mouse model of amyotrophic lateral sclerosis

    Directory of Open Access Journals (Sweden)

    Cheng Alice

    2011-07-01

    Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS is a devastating neurodegenerative disease that affects spinal cord and cortical motor neurons. An increasing amount of evidence suggests that mitochondrial dysfunction contributes to motor neuron death in ALS. Peroxisome proliferator-activated receptor gamma co-activator-1α (PGC-1α is a principal regulator of mitochondrial biogenesis and oxidative metabolism. Results In this study, we examined whether PGC-1α plays a protective role in ALS by using a double transgenic mouse model where PGC-1α is over-expressed in an SOD1 transgenic mouse (TgSOD1-G93A/PGC-1α. Our results indicate that PGC-1α significantly improves motor function and survival of SOD1-G93A mice. The behavioral improvements were accompanied by reduced blood glucose level and by protection of motor neuron loss, restoration of mitochondrial electron transport chain activities and inhibition of stress signaling in the spinal cord. Conclusion Our results demonstrate that PGC-1α plays a beneficial role in a mouse model of ALS, suggesting that PGC-1α may be a potential therapeutic target for ALS therapy.

  18. LINE-1 ORF-1p functions as a novel androgen receptor co-activator and promotes the growth of human prostatic carcinoma cells.

    Science.gov (United States)

    Lu, Yinying; Feng, Fan; Yang, Yutao; Gao, Xudong; Cui, Jiajun; Zhang, Chuanfu; Zhang, Fan; Xu, Zhongxian; Qv, Jianhui; Wang, Chunping; Zeng, Zhen; Zhu, Yunfeng; Yang, Yongping

    2013-02-01

    Widespread interest in the mechanism of transcriptional regulation by the androgen receptor (AR) has been stimulated by the finding that AR signaling is critically important in the progression of human prostate cancers. Co-factors, the co-repressors, or the co-activators are responsible for the regulation of AR activation. The pro-oncogene human Long Interspersed Nucleotide acid Element-1 (LINE-1) encodes LINE-1 ORF-1p and plays important roles in the development and progression of several human carcinomas. In this study, the results showed that LINE-1 ORF-1p increased the AR transcriptional activity and in turn enhanced the expression of prostate specific antigen (PSA) in the presence of R1881. A physical protein-protein interaction between the AR signaling and the LINE-1 ORF-1p was identified by the immunoprecipitation assays and GST pull-down assays. Furthermore, LINE-1 ORF-1p would function as a novel AR positive co-regulator through modulating its cytoplasm/nucleus translocation and the recruitment to the androgen response element in the PSA gene promoter. Our date also showed that the LINE-1 ORF-1p promoted the proliferation and anchor-independent growth of LNCaP (ligand dependent) and PC-3 (ligand independent) human prostatic carcinoma cells. By investigating a novel role of the LINE-1 ORF-1p in the androgen/androgen receptor signaling pathway regulation, our study identifies that LINE-1 ORF-1p may be a novel AR co-regulator and molecular target for human prostate carcinoma therapy.

  19. Post-traumatic stress avoidance is attenuated by corticosterone and associated with brain levels of steroid receptor co-activator-1 in rats.

    Science.gov (United States)

    Whitaker, Annie M; Farooq, Muhammad A; Edwards, Scott; Gilpin, Nicholas W

    2016-01-01

    Individuals with post-traumatic stress disorder (PTSD) avoid trauma-related stimuli and exhibit blunted hypothalamic-pituitary-adrenal (HPA) axis activation at the time of stress. Our rodent model of stress mimics the avoidance symptom cluster of PTSD. Rats are classified as "Avoiders" or "Non-Avoiders" post-stress based on the avoidance of a predator-odor paired context. Previously, we found Avoiders exhibit an attenuated HPA stress response to predator odor. We hypothesized that corticosterone administration before stress would reduce the magnitude and incidence of stress-paired context avoidance. Furthermore, we also predicted that Avoiders would exhibit altered expression of glucocorticoid receptor (GR) signaling machinery elements, including steroid receptor co-activator (SRC)-1. Male Wistar rats (n = 16) were pretreated with corticosterone (25 mg/kg) or saline and exposed to predator-odor stress paired with a context and tested for avoidance 24 h later. A second group of corticosterone-naïve rats (n = 24) were stressed (or not), indexed for avoidance 24 h later, and killed 48 h post-odor exposure to measure phosphorylated GR, FKBP51 and SRC-1 levels in the paraventricular nucleus (PVN), central amygdala (CeA) and ventral hippocampus (VH), all brain sites that highly express GRs and regulate HPA function. Corticosterone pretreatment reduced the magnitude and incidence of avoidance. In Avoiders, predator-odor exposure led to lower SRC-1 expression in the PVN and CeA, and higher SRC-1 expression in the VH. SRC-1 expression in PVN, CeA and VH was predicted by prior avoidance behavior. Hence, a blunted HPA stress response may contribute to stress-induced neuroadaptations in central SRC-1 levels and behavioral dysfunction in Avoider rats.

  20. Identification of VDR Antagonists among Nuclear Receptor Ligands Using Virtual Screening

    Directory of Open Access Journals (Sweden)

    Kelly Teske

    2014-04-01

    Full Text Available Herein, we described the development of two virtual screens to identify new vitamin D receptor (VDR antagonists among nuclear receptor (NR ligands. Therefore, a database of 14330 nuclear receptor ligands and their NR affinities was assembled using the online available “Binding Database.” Two different virtual screens were carried out in conjunction with a reported VDR crystal structure applying a stringent and less stringent pharmacophore model to filter docked NR ligand conformations. The pharmacophore models were based on the spatial orientation of the hydroxyl functionalities of VDR's natural ligands 1,25(OH2D3 and 25(OH2D3. The first virtual screen identified 32 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. All but nordihydroguaiaretic acid (NDGA are VDR ligands, which inhibited the interaction between VDR and coactivator peptide SRC2-3 with an IC50 value of 15.8 μM. The second screen identified 162 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. More than half of these ligands were developed to bind VDR followed by ERα/β ligands (26%, TRα/β ligands (7%, and LxRα/β ligands (7%. The binding between VDR and ERα ligand H6036 as well as TRα/β ligand triiodothyronine and a homoserine analog thereof was confirmed by fluorescence polarization.

  1. Non-canonical modulators of nuclear receptors.

    Science.gov (United States)

    Tice, Colin M; Zheng, Ya-Jun

    2016-09-01

    Like G protein-coupled receptors (GPCRs) and protein kinases, nuclear receptors (NRs) are a rich source of pharmaceutical targets. Over 80 NR-targeting drugs have been approved for 18 NRs. The focus of drug discovery in NRs has hitherto been on identifying ligands that bind to the canonical ligand binding pockets of the C-terminal ligand binding domains (LBDs). Due to the development of drug resistance and selectivity concerns, there has been considerable interest in exploring other, non-canonical ligand binding sites. Unfortunately, the potencies of compounds binding at other sites have generally not been sufficient for clinical development. However, the situation has changed dramatically over the last 3years, as compounds with sufficient potency have been reported for several NR targets. Here we review recent developments in this area from a medicinal chemistry point of view in the hope of stimulating further interest in this area of research.

  2. Co-active receptor tyrosine kinases mitigate the effect of FGFR inhibitors in FGFR1-amplified lung cancers with low FGFR1 protein expression.

    Science.gov (United States)

    Kotani, H; Ebi, H; Kitai, H; Nanjo, S; Kita, K; Huynh, T G; Ooi, A; Faber, A C; Mino-Kenudson, M; Yano, S

    2016-07-07

    Targeted therapies are effective in subsets of lung cancers with EGFR mutations and anaplastic lymphoma kinase (ALK) translocations. Large-scale genomics have recently expanded the lung cancer landscape with FGFR1 amplification found in 10-20% of squamous cell carcinomas (SCCs). However, the response rates have been low for biomarker-directed fibroblast growth factor receptor (FGFR) inhibitor therapy in SCC, which contrasts to the relatively high rates of response seen in EGFR mutant and ALK-translocated lung cancers treated with epidermal growth factor receptor (EGFR) inhibitors and ALK inhibitors, respectively. In order to better understand the low response rates of FGFR1-amplified lung cancers to FGFR inhibitors, relationships between gene copy number, mRNA expression and protein expression of FGFR1 were assessed in cell lines, tumor specimens and data from The Cancer Genome Atlas. The importance of these factors for the sensitivity to FGFR inhibitors was determined by analyzing drug screen data and conducting in vitro and in vivo experiments. We report that there was a discrepancy between FGFR1 amplification level and FGFR1 protein expression in a number of these cell lines, and the cancers with unexpectedly low FGFR1 expression were uniformly resistant to the different FGFR inhibitors. Further interrogation of the receptor tyrosine kinase activity in these discordant cell lines revealed co-activation of HER2 and platelet-derived growth factor receptor-α (PDGFRα) caused by gene amplification or ligand overexpression maintained phosphoinositide 3-kinase (PI3K) and MEK/ERK signaling even in the presence of FGFR inhibitor. Accordingly, co-inhibition of FGFR1 and HER2 or PDGFRα led to enhanced drug responses. In contrast, FGFR1-amplified high FGFR1 protein-expressing lung cancers are sensitive to FGFR inhibitor monotherapy by downregulating ERK signaling. Addition of a PI3K inhibitor to these high FGFR1 protein-expressing cancers further sensitized them to FGFR

  3. Nuclear hormone receptors put immunity on sterols.

    Science.gov (United States)

    Santori, Fabio R

    2015-10-01

    Nuclear hormone receptors (NHRs) are transcription factors regulated by small molecules. The functions of NHRs range from development of primary and secondary lymphoid organs, to regulation of differentiation and function of DCs, macrophages and T cells. The human genome has 48 classic (hormone and vitamin receptors) and nonclassic (all others) NHRs; 17 nonclassic receptors are orphans, meaning that the endogenous ligand is unknown. Understanding the function of orphan NHRs requires the identification of their natural ligands. The mevalonate pathway, including its sterol and nonsterol intermediates and derivatives, is a source of ligands for many classic and nonclassic NHRs. For example, cholesterol biosynthetic intermediates (CBIs) are natural ligands for RORγ/γt. CBIs are universal endogenous metabolites in mammalian cells, and to study NHRs that bind CBIs requires ligand-free reporters system in sterol auxotroph cells. Furthermore, RORγ/γt shows broad specificity to sterol lipids, suggesting that RORγ/γt is either a general sterol sensor or specificity is defined by an abundant endogenous ligand. Unlike other NHRs, which regulate specific metabolic pathways, there is no connection between the genetic programs induced by RORγ/γt and ligand biosynthesis. In this review, we summarize the roles of nonclassic NHRs and their potential ligands in the immune system.

  4. Minireview: nuclear receptor coregulators of the p160 family: insights into inflammation and metabolism.

    Science.gov (United States)

    Rollins, David A; Coppo, Maddalena; Rogatsky, Inez

    2015-04-01

    Nuclear receptor coactivators (NCOAs) are multifunctional transcriptional coregulators for a growing number of signal-activated transcription factors. The members of the p160 family (NCOA1/2/3) are increasingly recognized as essential and nonredundant players in a number of physiological processes. In particular, accumulating evidence points to the pivotal roles that these coregulators play in inflammatory and metabolic pathways, both under homeostasis and in disease. Given that chronic inflammation of metabolic tissues ("metainflammation") is a driving force for the widespread epidemic of obesity, insulin resistance, cardiovascular disease, and associated comorbidities, deciphering the role of NCOAs in "normal" vs "pathological" inflammation and in metabolic processes is indeed a subject of extreme biomedical importance. Here, we review the evolving and, at times, contradictory, literature on the pleiotropic functions of NCOA1/2/3 in inflammation and metabolism as related to nuclear receptor actions and beyond. We then briefly discuss the potential utility of NCOAs as predictive markers for disease and/or possible therapeutic targets once a better understanding of their molecular and physiological actions is achieved.

  5. A nuclear receptor-like pathway regulating multidrug resistance in fungi.

    Science.gov (United States)

    Thakur, Jitendra K; Arthanari, Haribabu; Yang, Fajun; Pan, Shih-Jung; Fan, Xiaochun; Breger, Julia; Frueh, Dominique P; Gulshan, Kailash; Li, Darrick K; Mylonakis, Eleftherios; Struhl, Kevin; Moye-Rowley, W Scott; Cormack, Brendan P; Wagner, Gerhard; Näär, Anders M

    2008-04-03

    Multidrug resistance (MDR) is a serious complication during treatment of opportunistic fungal infections that frequently afflict immunocompromised individuals, such as transplant recipients and cancer patients undergoing cytotoxic chemotherapy. Improved knowledge of the molecular pathways controlling MDR in pathogenic fungi should facilitate the development of novel therapies to combat these intransigent infections. MDR is often caused by upregulation of drug efflux pumps by members of the fungal zinc-cluster transcription-factor family (for example Pdr1p orthologues). However, the molecular mechanisms are poorly understood. Here we show that Pdr1p family members in Saccharomyces cerevisiae and the human pathogen Candida glabrata directly bind to structurally diverse drugs and xenobiotics, resulting in stimulated expression of drug efflux pumps and induction of MDR. Notably, this is mechanistically similar to regulation of MDR in vertebrates by the PXR nuclear receptor, revealing an unexpected functional analogy of fungal and metazoan regulators of MDR. We have also uncovered a critical and specific role of the Gal11p/MED15 subunit of the Mediator co-activator and its activator-targeted KIX domain in antifungal/xenobiotic-dependent regulation of MDR. This detailed mechanistic understanding of a fungal nuclear receptor-like gene regulatory pathway provides novel therapeutic targets for the treatment of multidrug-resistant fungal infections.

  6. CREB controls hepatic lipid metabolism through nuclear hormone receptor PPAR-gamma.

    Science.gov (United States)

    Herzig, Stephan; Hedrick, Susan; Morantte, Ianessa; Koo, Seung-Hoi; Galimi, Francesco; Montminy, Marc

    2003-11-13

    Fasting triggers a series of hormonal cues that promote energy balance by inducing glucose output and lipid breakdown in the liver. In response to pancreatic glucagon and adrenal cortisol, the cAMP-responsive transcription factor CREB activates gluconeogenic and fatty acid oxidation programmes by stimulating expression of the nuclear hormone receptor coactivator PGC-1 (refs 2-5). In parallel, fasting also suppresses lipid storage and synthesis (lipogenic) pathways, but the underlying mechanism is unknown. Here we show that mice deficient in CREB activity have a fatty liver phenotype and display elevated expression of the nuclear hormone receptor PPAR-gamma, a key regulator of lipogenic genes. CREB inhibits hepatic PPAR-gamma expression in the fasted state by stimulating the expression of the Hairy Enhancer of Split (HES-1) gene, a transcriptional repressor that is shown here to be a mediator of fasting lipid metabolism in vivo. The coordinate induction of PGC-1 and repression of PPAR-gamma by CREB during fasting provides a molecular rationale for the antagonism between insulin and counter-regulatory hormones, and indicates a potential role for CREB antagonists as therapeutic agents in enhancing insulin sensitivity in the liver.

  7. Research Resources for Nuclear Receptor Signaling Pathways.

    Science.gov (United States)

    McKenna, Neil J

    2016-08-01

    Nuclear receptor (NR) signaling pathways impact cellular function in a broad variety of tissues in both normal physiology and disease states. The complex tissue-specific biology of these pathways is an enduring impediment to the development of clinical NR small-molecule modulators that combine therapeutically desirable effects in specific target tissues with suppression of off-target effects in other tissues. Supporting the important primary research in this area is a variety of web-based resources that assist researchers in gaining an appreciation of the molecular determinants of the pharmacology of a NR pathway in a given tissue. In this study, selected representative examples of these tools are reviewed, along with discussions on how current and future generations of tools might optimally adapt to the future of NR signaling research. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  8. Role of nuclear receptor Nur77 during inflammation

    NARCIS (Netherlands)

    Hamers, A.A.J.

    2015-01-01

    Nuclear Receptors play key roles in cell differentiation and development, homeostasis and in many diseases such as diabetes, cancer, cardiovascular disease, reproductive abnormalities and obesity; and are therefore major targets for drug discovery. Nur77 is, like most nuclear receptors, a transcript

  9. Nuclear receptors as drug targets for metabolic disease

    NARCIS (Netherlands)

    Schulman, Ira G.

    2010-01-01

    Nuclear hormone receptors comprise a superfamily of ligand-activated transcription factors that control development, differentiation, and homeostasis. Over the last 15 years a growing number of nuclear receptors have been identified that coordinate genetic networks regulating lipid metabolism and en

  10. Nuclear receptors as drug targets for metabolic disease

    NARCIS (Netherlands)

    Schulman, Ira G.

    2010-01-01

    Nuclear hormone receptors comprise a superfamily of ligand-activated transcription factors that control development, differentiation, and homeostasis. Over the last 15 years a growing number of nuclear receptors have been identified that coordinate genetic networks regulating lipid metabolism and en

  11. A Nonnatural Transcriptional Coactivator

    Science.gov (United States)

    Nyanguile, Origene; Uesugi, Motonari; Austin, David J.; Verdine, Gregory L.

    1997-12-01

    In eukaryotes, sequence-specific DNA-binding proteins activate gene expression by recruiting the transcriptional apparatus and chromatin remodeling proteins to the promoter through protein-protein contacts. In many instances, the connection between DNA-binding proteins and the transcriptional apparatus is established through the intermediacy of adapter proteins known as coactivators. Here we describe synthetic molecules with low molecular weight that act as transcriptional coactivators. We demonstrate that a completely nonnatural activation domain in one such molecule is capable of stimulating transcription in vitro and in vivo. The present strategy provides a means of gaining external control over gene activation through intervention using small molecules.

  12. TAZ: a novel transcriptional co-activator regulated by interactions with 14-3-3 and PDZ domain proteins.

    Science.gov (United States)

    Kanai, F; Marignani, P A; Sarbassova, D; Yagi, R; Hall, R A; Donowitz, M; Hisaminato, A; Fujiwara, T; Ito, Y; Cantley, L C; Yaffe, M B

    2000-12-15

    The highly conserved and ubiquitously expressed 14-3-3 proteins regulate differentiation, cell cycle progression and apoptosis by binding intracellular phosphoproteins involved in signal transduction. By screening in vitro translated cDNA pools for the ability to bind 14-3-3, we identified a novel transcriptional co-activator, TAZ (transcriptional co-activator with PDZ-binding motif) as a 14-3-3-binding molecule. TAZ shares homology with Yes-associated protein (YAP), contains a WW domain and functions as a transcriptional co-activator by binding to the PPXY motif present on transcription factors. 14-3-3 binding requires TAZ phosphorylation on a single serine residue, resulting in the inhibition of TAZ transcriptional co-activation through 14-3-3-mediated nuclear export. The C-terminus of TAZ contains a highly conserved PDZ-binding motif that localizes TAZ into discrete nuclear foci and is essential for TAZ-stimulated gene transcription. TAZ uses this same motif to bind the PDZ domain-containing protein NHERF-2, a molecule that tethers plasma membrane ion channels and receptors to cytoskeletal actin. TAZ may link events at the plasma membrane and cytoskeleton to nuclear transcription in a manner that can be regulated by 14-3-3.

  13. Mapping C-terminal transactivation domains of the nuclear HER family receptor tyrosine kinase HER3.

    Science.gov (United States)

    Brand, Toni M; Iida, Mari; Luthar, Neha; Wleklinski, Matthew J; Starr, Megan M; Wheeler, Deric L

    2013-01-01

    Nuclear localized HER family receptor tyrosine kinases (RTKs) have been observed in primary tumor specimens and cancer cell lines for nearly two decades. Inside the nucleus, HER family members (EGFR, HER2, and HER3) have been shown to function as co-transcriptional activators for various cancer-promoting genes. However, the regions of each receptor that confer transcriptional potential remain poorly defined. The current study aimed to map the putative transactivation domains (TADs) of the HER3 receptor. To accomplish this goal, various intracellular regions of HER3 were fused to the DNA binding domain of the yeast transcription factor Gal4 (Gal4DBD) and tested for their ability to transactivate Gal4 UAS-luciferase. Results from these analyses demonstrated that the C-terminal domain of HER3 (CTD, amino acids distal to the tyrosine kinase domain) contained potent transactivation potential. Next, nine HER3-CTD truncation mutants were constructed to map minimal regions of transactivation potential using the Gal4 UAS-luciferase based system. These analyses identified a bipartite region of 34 (B₁) and 27 (B₂) amino acids in length that conferred the majority of HER3's transactivation potential. Next, we identified full-length nuclear HER3 association and regulation of a 122 bp region of the cyclin D1 promoter. To understand how the B₁ and B₂ regions influenced the transcriptional functions of nuclear HER3, we performed cyclin D1 promoter-luciferase assays in which HER3 deleted of the B₁ and B₂ regions was severely hindered in regulating this promoter. Further, the overexpression of HER3 enhanced cyclin D1 mRNA expression, while HER3 deleted of its identified TADs was hindered at doing so. Thus, the ability for HER3 to function as a transcriptional co-activator may be dependent on specific C-terminal TADs.

  14. TReP-132 Is a Novel Progesterone Receptor Coactivator Required for the Inhibition of Breast Cancer Cell Growth and Enhancement of Differentiation by Progesterone

    Science.gov (United States)

    Gizard, Florence; Robillard, Romain; Gross, Barbara; Barbier, Olivier; Révillion, Françoise; Peyrat, Jean-Philippe; Torpier, Gérard; Hum, Dean W.; Staels, Bart

    2006-01-01

    The sex steroid progesterone is essential for the proliferation and differentiation of the mammary gland epithelium during pregnancy. In relation to this, in vitro studies using breast carcinoma T47D cells have demonstrated a biphasic progesterone response, consisting of an initial proliferative burst followed by a sustained growth arrest. However, the transcriptional factors acting with the progesterone receptor (PR) to mediate the progesterone effects on mammary cell growth and differentiation remain to be determined. Recently, it has been demonstrated that the transcriptional regulating protein of 132 kDa (TReP-132), initially identified as a regulator of steroidogenesis, is also a cell growth suppressor. Similar to progesterone-bound PR, TReP-132 acts by inducing the gene expression of the G1 cyclin-dependent kinase inhibitors p21WAF1/Cip1 (p21) and p27Kip1 (p27). The putative interaction between TReP-132 and progesterone pathways in mammary cells was therefore analyzed in the present study. Our results show that TReP-132 interacts in vitro and in T47D cells with progesterone-activated PR. TReP-132 synergizes with progesterone-bound PR to trans activate the p21 and p27 gene promoters at proximal Sp1-binding sites. Moreover, TReP-132 overexpression and knockdown, respectively, increased or prevented the induction of p21 and p27 gene expression by progesterone. As a consequence, TReP-132 knockdown also resulted in the loss of the inhibitory effects of progesterone on pRB phosphorylation, G1/S cell cycle progression, and cell proliferation. Furthermore, the knockdown of TReP-132 expression also prevented the induction of both early and terminal markers of breast cell differentiation which had been previously identified as progesterone target genes. As well, the progesterone-induced accumulation of lipid vacuoles was inhibited in the TReP-132-depleted cells. Finally, TReP-132 gene expression levels increased following progesterone treatment, indicating the

  15. Effect of insulin and metformin on methylation and glycolipid metabolism of peroxisome proliferator-activated receptor γcoactivator-1A of rat offspring with gestational diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    Ai-Qin Song; Li-Rong Sun; Yan-Xia Zhao; Yan-Hua Gao; Lei Chen

    2016-01-01

    Objective: To discuss the effect of insulin and metformin on amethylation and glycolipid metabolism of peroxisome proliferator-activated receptor γ coactivator-1A (PPARGC1A) ofrat offspring with gestational diabetes mellitus (GDM). Methods: A total of 45 pregnant rats received the intraperitoneal injection of streptozotocin to establish the pregnant rat model of GDM. A total of 21 pregnant rats with GDM were randomly divided into three groups, with 7 rats in each group, namely the insulin group, metformin group and control group. Rats in the insulin group received the abdominal subcutaneous injection of 1 mL/kg recombinant insulin glargine at 18: 00 every day. Rats in the metformin group received the intragastric infusion of metformin hydrochloride at 18: 00 every day, with the first dose of 300 mg/kg. The doses of two groups were adjusted every 3 d to maintain the blood glucose level at 2.65-7.62 mmol/L. Rats in the control group received the intragastric infusion of 1 mL normal saline at 18:00 every day. After the natural delivery of pregnant rats, 10 offspring rats were randomly selected from each group. At birth, 4 wk and 8 wk after the birth of offspring rats, the weight of offspring rats was measured. The blood glucose level of offspring rats was measured at 4 wk and 8 wk, while the level of serum insulin, triglyceride and leptin was measured at 8 wk.Results: The weight of offspring rats at birth in the insulin group and metformin group was significantly lower than the one in the control group (P0.05). The fasting blood glucose and random blood glucose in the insulin group and metformin group at 4 wk and 8 wk were all significantly lower than ones in the control group (P0.05). The expression of PPARGC1A mRNA in the insulin group and metformin group was significantly higher and the methylation level of PPARGC1A was significantly lower than the one in the control group (P0.05). Insulin and leptin at 8 wk in the insulin group and metformin group were

  16. A model for aryl hydrocarbon receptor-activated gene expression shows potency and efficacy changes and predicts squelching due to competition for transcription co-activators.

    Directory of Open Access Journals (Sweden)

    Ted W Simon

    Full Text Available A stochastic model of nuclear receptor-mediated transcription was developed based on activation of the aryl hydrocarbon receptor (AHR by 2,3,7,8-tetrachlorodibenzodioxin (TCDD and subsequent binding the activated AHR to xenobiotic response elements (XREs on DNA. The model was based on effects observed in cells lines commonly used as in vitro experimental systems. Following ligand binding, the AHR moves into the cell nucleus and forms a heterodimer with the aryl hydrocarbon nuclear translocator (ARNT. In the model, a requirement for binding to DNA is that a generic coregulatory protein is subsequently bound to the AHR-ARNT dimer. Varying the amount of coregulator available within the nucleus altered both the potency and efficacy of TCDD for inducing for transcription of CYP1A1 mRNA, a commonly used marker for activation of the AHR. Lowering the amount of available cofactor slightly increased the EC50 for the transcriptional response without changing the efficacy or maximal response. Further reduction in the amount of cofactor reduced the efficacy and produced non-monotonic dose-response curves (NMDRCs at higher ligand concentrations. The shapes of these NMDRCs were reminiscent of the phenomenon of squelching. Resource limitations for transcriptional machinery are becoming apparent in eukaryotic cells. Within single cells, nuclear receptor-mediated gene expression appears to be a stochastic process; however, intercellular communication and other aspects of tissue coordination may represent a compensatory process to maintain an organism's ability to respond on a phenotypic level to various stimuli within an inconstant environment.

  17. Mediator subunit MED1 is a T3-dependent and T3-independent coactivator on the thyrotropin β gene promoter

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Keiji; Oda, Kasumi; Mizuta, Shumpei; Ishino, Ruri; Urahama, Norinaga; Hasegawa, Natsumi [Laboratory of Hematology, Division of Medical Biophysics, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142 (Japan); Roeder, Robert G. [Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States); Ito, Mitsuhiro, E-mail: itomi@med.kobe-u.ac.jp [Laboratory of Hematology, Division of Medical Biophysics, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142 (Japan); Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States); Department of Family and Community Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 654-0142 (Japan); Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 159-8555 (Japan)

    2013-10-11

    Highlights: •MED1 is a bona fide T3-dependent coactivator on TSHB promoter. •Mice with LxxLL-mutant MED1 have attenuated TSHβ mRNA and thyroid hormone levels. •MED1 activates TSHB promoter T3-dependently in cultured cells. •T3-dependent MED1 action is enhanced when SRC1/SRC2 or HDAC2 is downregulated. •MED1 is also a T3-independent GATA2/Pit1 coactivator on TSHB promoter. -- Abstract: The MED1 subunit of the Mediator transcriptional coregulator complex is a nuclear receptor-specific coactivator. A negative feedback mechanism of thyroid-stimulating hormone (TSH, or thyrotropin) expression in the thyrotroph in the presence of triiodothyronine (T3) is employed by liganded thyroid hormone receptor β (TRβ) on the TSHβ gene promoter, where conventional histone-modifying coactivators act as corepressors. We now provide evidence that MED1 is a ligand-dependent positive cofactor on this promoter. TSHβ gene transcription was attenuated in MED1 mutant mice in which the nuclear receptor-binding ability of MED1 was specifically disrupted. MED1 stimulated GATA2- and Pit1-mediated TSHβ gene promoter activity in a ligand-independent manner in cultured cells. MED1 also stimulated transcription from the TSHβ gene promoter in a T3-dependent manner. The transcription was further enhanced when the T3-dependent corepressors SRC1, SRC2, and HDAC2 were downregulated. Hence, MED1 is a T3-dependent and -independent coactivator on the TSHβ gene promoter.

  18. Nuclear receptor complement of the cnidarian Nematostella vectensis: phylogenetic relationships and developmental expression patterns

    Directory of Open Access Journals (Sweden)

    Tarrant Ann M

    2009-09-01

    Full Text Available Abstract Background Nuclear receptors are a superfamily of metazoan transcription factors that regulate diverse developmental and physiological processes. Sequenced genomes from an increasing number of bilaterians have provided a more complete picture of duplication and loss of nuclear receptors in protostomes and deuterostomes but have left open the question of which nuclear receptors were present in the cnidarian-bilaterian ancestor. In addition, nuclear receptor expression and function are largely uncharacterized within cnidarians, preventing determination of conserved and novel nuclear receptor functions in the context of animal evolution. Results Here we report the first complete set of nuclear receptors from a cnidarian, the starlet sea anemone Nematostella vectensis. Genomic searches using conserved DNA- and ligand-binding domains revealed seventeen nuclear receptors in N. vectensis. Phylogenetic analyses support N. vectensis orthologs of bilaterian nuclear receptors in four nuclear receptor subfamilies within nuclear receptor family 2 (COUP-TF, TLL, HNF4, TR2/4 and one putative ortholog of GCNF (nuclear receptor family 6. Other N. vectensis genes grouped well with nuclear receptor family 2 but represented lineage-specific duplications somewhere within the cnidarian lineage and were not clear orthologs of bilaterian genes. Three nuclear receptors were not well-supported within any particular nuclear receptor family. The seventeen nuclear receptors exhibited distinct developmental expression patterns, with expression of several nuclear receptors limited to a subset of developmental stages. Conclusion N. vectensis contains a diverse complement of nuclear receptors including orthologs of several bilaterian nuclear receptors. Novel nuclear receptors in N. vectensis may be ancient genes lost from triploblastic lineages or may represent cnidarian-specific radiations. Nuclear receptors exhibited distinct developmental expression patterns, which

  19. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

    Directory of Open Access Journals (Sweden)

    Lauren B Becnel

    Full Text Available Signaling pathways involving nuclear receptors (NRs, their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA is a Consortium focused around a Hub website (www.nursa.org that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs. These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field.

  20. Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

    Science.gov (United States)

    Becnel, Lauren B; Darlington, Yolanda F; Ochsner, Scott A; Easton-Marks, Jeremy R; Watkins, Christopher M; McOwiti, Apollo; Kankanamge, Wasula H; Wise, Michael W; DeHart, Michael; Margolis, Ronald N; McKenna, Neil J

    2015-01-01

    Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field.

  1. NCOA4 transcriptional coactivator inhibits activation of DNA replication origins.

    Science.gov (United States)

    Bellelli, Roberto; Castellone, Maria Domenica; Guida, Teresa; Limongello, Roberto; Dathan, Nina Alayne; Merolla, Francesco; Cirafici, Anna Maria; Affuso, Andrea; Masai, Hisao; Costanzo, Vincenzo; Grieco, Domenico; Fusco, Alfredo; Santoro, Massimo; Carlomagno, Francesca

    2014-07-01

    NCOA4 is a transcriptional coactivator of nuclear hormone receptors that undergoes gene rearrangement in human cancer. By combining studies in Xenopus laevis egg extracts and mouse embryonic fibroblasts (MEFs), we show here that NCOA4 is a minichromosome maintenance 7 (MCM7)-interacting protein that is able to control DNA replication. Depletion-reconstitution experiments in Xenopus laevis egg extracts indicate that NCOA4 acts as an inhibitor of DNA replication origin activation by regulating CMG (CDC45/MCM2-7/GINS) helicase. NCOA4(-/-) MEFs display unscheduled origin activation and reduced interorigin distance; this results in replication stress, as shown by the presence of fork stalling, reduction of fork speed, and premature senescence. Together, our findings indicate that NCOA4 acts as a regulator of DNA replication origins that helps prevent inappropriate DNA synthesis and replication stress.

  2. Studying Nuclear Receptor Complexes in the Cellular Environment.

    Science.gov (United States)

    Schaufele, Fred

    2016-01-01

    The ligand-regulated structure and biochemistry of nuclear receptor complexes are commonly determined by in vitro studies of isolated receptors, cofactors, and their fragments. However, in the living cell, the complexes that form are governed not just by the relative affinities of isolated cofactors for the receptor but also by the cell-specific sequestration or concentration of subsets of competing or cooperating cofactors, receptors, and other effectors into distinct subcellular domains and/or their temporary diversion into other cellular activities. Most methods developed to understand nuclear receptor function in the cellular environment involve the direct tagging of the nuclear receptor or its cofactors with fluorescent proteins (FPs) and the tracking of those FP-tagged factors by fluorescence microscopy. One of those approaches, Förster resonance energy transfer (FRET) microscopy, quantifies the transfer of energy from a higher energy "donor" FP to a lower energy "acceptor" FP attached to a single protein or to interacting proteins. The amount of FRET is influenced by the ligand-induced changes in the proximities and orientations of the FPs within the tagged nuclear receptor complexes, which is an indicator of the structure of the complexes, and by the kinetics of the interaction between FP-tagged factors. Here, we provide a guide for parsing information about the structure and biochemistry of nuclear receptor complexes from FRET measurements in living cells.

  3. Identification of Gene Markers for Activation of the Nuclear Receptor Pregnane X Receptor

    Science.gov (United States)

    Many environmentally-relevant chemicals and drugs activate the nuclear receptor pregnane X receptor (PXR). Activation of PXR in the mouse liver can lead to increases in liver weight in part through increased hepatocyte replication similar to chemicals that activate other nuclear ...

  4. Identification of Gene Markers for Activation of the Nuclear Receptor Pregnane X Receptor

    Science.gov (United States)

    Many environmentally-relevant chemicals and drugs activate the nuclear receptor pregnane X receptor (PXR). Activation of PXR in the mouse liver can lead to increases in liver weight in part through increased hepatocyte replication similar to chemicals that activate other nuclear ...

  5. Carob pod insoluble fiber exerts anti-atherosclerotic effects in rabbits through sirtuin-1 and peroxisome proliferator-activated receptorcoactivator-1α.

    Science.gov (United States)

    Valero-Muñoz, María; Martín-Fernández, Beatriz; Ballesteros, Sandra; Lahera, Vicente; de las Heras, Natalia

    2014-09-01

    The aim of this study was to evaluate the potential effects of an insoluble dietary fiber from carob pod (IFC) (1 g ⋅ kg(-1) ⋅ d(-1) in the diet) on alterations associated with atherosclerosis in rabbits with dyslipidemia. Male New Zealand rabbits (n = 30) were fed the following diets for 8 wk: 1) a control diet (SF412; Panlab) as a control group representing normal conditions; 2) a control supplemented with 0.5% cholesterol + 14% coconut oil (DL) (SF302; Panlab) for 8 wk as a dyslipidemic group; and 3) a control containing 0.5% cholesterol + 14% coconut oil plus IFC (1 g ⋅ kg(-1) ⋅ d(-1)) (DL+IFC) for 8 wk. IFC was administered in a pellet mixed with the DL diet. The DL-fed group developed mixed dyslipidemia and atherosclerotic lesions, which were associated with endothelial dysfunction, inflammation, and fibrosis. Furthermore, sirtuin-1 (SIRT1) and peroxisome proliferator-activated receptorcoactivator-1α (PGC-1α) protein expression in the aorta were reduced to 77% and 63% of the control group, respectively (P < 0.05), in these rabbits. Administration of IFC to DL-fed rabbits reduced the size of the aortic lesion significantly (DL, 15.2% and DL+IFC, 2.6%) and normalized acetylcholine-induced relaxation (maximal response: control, 89.3%; DL, 61.6%; DL+IFC, 87.1%; P < 0.05) and endothelial nitric oxide synthase expression (DL, 52% and DL+IFC, 104% of the control group). IFC administration to DL-fed rabbits also reduced cluster of differentiation 36 (DL, 148% and DL+IFC, 104% of the control group; P < 0.05), plasminogen activator inhibitor-1 (DL, 141% and DL+IFC, 107% of the control group), tumor necrosis factor-α (DL, 166% and DL+IFC, 120% of the control group), vascular cell adhesion molecule-1 (DL, 153% and DL+IFC, 110% of the control group), transforming growth factor-β (DL, 173% and DL+IFC, 99% of the control group), and collagen I (DL, 157% and DL+IFC, 112% of the control group) in the aorta. These effects were accompanied by an enhancement of

  6. Molecular basis for gene-specific transactivation by nuclear receptors

    DEFF Research Database (Denmark)

    Jørgensen, Mads Aagaard; Siersbæk, Rasmus; Mandrup, Susanne

    2010-01-01

    most likely be accounted for by mechanisms involving receptor-specific interactions with DNA as well as receptor-specific interactions with protein complexes binding to adjacent and distant DNA sequences. Here, we review key molecular aspects of transactivation by NRs with special emphasis......Nuclear receptors (NRs) are key transcriptional regulators of metazoan physiology and metabolism. Different NRs bind to similar or even identical core response elements; however, they regulate transcription in a highly receptor- and gene-specific manner. These differences in gene activation can...... on the recent advances in the molecular mechanisms responsible for receptor- and gene-specific transcriptional activation. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease....

  7. NucleaRDB: information system for nuclear receptors.

    Science.gov (United States)

    Vroling, Bas; Thorne, David; McDermott, Philip; Joosten, Henk-Jan; Attwood, Teresa K; Pettifer, Steve; Vriend, Gert

    2012-01-01

    The NucleaRDB is a Molecular Class-Specific Information System that collects, combines, validates and disseminates large amounts of heterogeneous data on nuclear hormone receptors. It contains both experimental and computationally derived data. The data and knowledge present in the NucleaRDB can be accessed using a number of different interactive and programmatic methods and query systems. A nuclear hormone receptor-specific PDF reader interface is available that can integrate the contents of the NucleaRDB with full-text scientific articles. The NucleaRDB is freely available at http://www.receptors.org/nucleardb.

  8. [Mechanism for subcellular localization of nuclear receptor CAR].

    Science.gov (United States)

    Kanno, Yuichiro; Inouye, Yoshio

    2011-03-01

    Animals including human beings have defense mechanisms against the toxicity of xenobiotics such as medicinal compounds and environmental pollutants. Receptor-type transcriptional factors, such as aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR) and pregnane X receptor (PXR), play important roles in the defense against xenobiotic toxicities. In the absence of stimuli, these receptors are distributed predominantly in the cytoplasmic compartment. Following xenobiotic stimuli, receptors translocate into the nucleus and transactivate its target genes. However, the exogenously expressed CAR translocates spontaneously into the nucleus in immortal cells. Previously, we identified subcellular localization signals in rat CAR: nuclear localization signal (NLS), nuclear export signal (NES) and cytoplasmic retention region (CRR). Lack of CRR function might be responsible for the spontaneous nuclear accumulation of CAR in immortal cells. Further, the nuclear import of CAR is regulated by the importin-Ran system, which is required for maintaining an intact microtubule network. Clarifying the mechanisms underlying the nuclear translocation of CAR would be useful for the establishment of novel assay systems for the screening of ligands and activators of CAR using immortal cells without sacrificing animals.

  9. Biochemical characterization of nuclear receptors for vitamin D{sub 3} and glucocorticoids in prostate stroma cell microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, Alejandro A. [Laboratory of Molecular Endocrinology, Department of Physiopathology, University of Concepcion, Concepcion (Chile); Department of Molecular Pharmacology and Therapeutics, NY (United States); Montecinos, Viviana P.; Paredes, Roberto; Godoy, Alejandro S.; McNerney, Eileen M.; Tovar, Heribelt; Pantoja, Diego [Laboratory of Molecular Endocrinology, Department of Physiopathology, University of Concepcion, Concepcion (Chile); Johnson, Candace [Department of Molecular Pharmacology and Therapeutics, NY (United States); Trump, Donald [Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY (United States); Onate, Sergio A., E-mail: sergio.onate@udec.cl [Laboratory of Molecular Endocrinology, Department of Physiopathology, University of Concepcion, Concepcion (Chile); Department of Urology, State University of New York at Buffalo, NY (United States)

    2011-08-19

    Highlights: {yields} Fibroblasts from benign and carcinoma-associated stroma were biochemically characterized for VDR and GR function as transcription factors in prostate stroma cell microenvironment. {yields} Decreased SRC-1/CBP coactivators recruitment to VDR and GR may result in hormone resistance to 1,25D{sub 3} in stromal cell microenvironment prostate cancer. {yields} 1a,25-Dyhidroxyvitamin D{sub 3} (1,25D{sub 3}) and glucocorticoids, either alone or in combination, may not be an alternative for 'some' advanced prostate cancers that fails androgen therapies. -- Abstract: The disruption of stromal cell signals in prostate tissue microenvironment influences the development of prostate cancer to androgen independence. 1{alpha},25-Dihydroxyvitamin D{sub 3} (1,25D{sub 3}) and glucocorticoids, either alone or in combination, have been investigated as alternatives for the treatment of advanced prostate cancers that fails androgen therapies. The effects of glucocorticoids are mediated by the intracellular glucocorticoid receptor (GR). Similarly, the effect of 1,25D{sub 3} is mediated by the 1,25D{sub 3} nuclear receptor (VDR). In this study, fibroblasts from benign- (BAS) and carcinoma-associated stroma (CAS) were isolated from human prostates to characterize VDR and GR function as transcription factors in prostate stroma. The VDR-mediated transcriptional activity assessed using the CYP24-luciferase reporter was limited to 3-fold induction by 1,25D{sub 3} in 9 out of 13 CAS (70%), as compared to >10-fold induction in the BAS clinical sample pair. Expression of His-tagged VDR (Ad-his-VDR) failed to recover the low transcriptional activity of the luciferase reporter in 7 out of 9 CAS. Interestingly, expression of Ad-his-VDR successfully recovered receptor-mediated induction in 2 out of the 9 CAS analyzed, suggesting that changes in the receptor protein itself was responsible for decreased response and resistance to 1,25D{sub 3} action. Conversely, VDR

  10. Distinct recognition modes of FXXLF and LXXLL motifs by the androgen receptor.

    NARCIS (Netherlands)

    H.J. Dubbink (Erik Jan); R. Hersmus (Remko); C.S. Verma (Chandra); H.A.G.M. van der Korput (Hetty); C.A. Berrevoets (Cor); J. van Tol (Judith); A.C.J. Ziel-van der Made (Angelique); A.O. Brinkmann (Albert); A.C. Pike (Ashley); J. Trapman (Jan)

    2004-01-01

    textabstractAmong nuclear receptors, the androgen receptor (AR) is unique in that its ligand-binding domain (LBD) interacts with the FXXLF motif in the N-terminal domain, resembling coactivator LXXLL motifs. We compared AR- and estrogen receptor alpha-LBD interactions of the wild-t

  11. The HIV matrix protein p17 induces hepatic lipid accumulation via modulation of nuclear receptor transcriptoma.

    Science.gov (United States)

    Renga, Barbara; Francisci, Daniela; Carino, Adriana; Marchianò, Silvia; Cipriani, Sabrina; Chiara Monti, Maria; Del Sordo, Rachele; Schiaroli, Elisabetta; Distrutti, Eleonora; Baldelli, Franco; Fiorucci, Stefano

    2015-10-15

    Liver disease is the second most common cause of mortality in HIV-infected persons. Exactly how HIV infection per se affects liver disease progression is unknown. Here we have investigated mRNA expression of 49 nuclear hormone receptors (NRs) and 35 transcriptional coregulators in HepG2 cells upon stimulation with the HIV matrix protein p17. This viral protein regulated mRNA expression of some NRs among which LXRα and its transcriptional co-activator MED1 were highly induced at mRNA level. Dissection of p17 downstream intracellular pathway demonstrated that p17 mediated activation of Jak/STAT signaling is responsible for the promoter dependent activation of LXR. The treatment of both HepG2 as well as primary hepatocytes with HIV p17 results in the transcriptional activation of LXR target genes (SREBP1c and FAS) and lipid accumulation. These effects are lost in HepG2 cells pre-incubated with a serum from HIV positive person who underwent a vaccination with a p17 peptide as well as in HepG2 cells pre-incubated with the natural LXR antagonist gymnestrogenin. These results suggest that HIV p17 affects NRs and their related signal transduction thus contributing to the progression of liver disease in HIV infected patients.

  12. Pan-cancer analyses of the nuclear receptor superfamily

    Science.gov (United States)

    Long, Mark D.; Campbell, Moray J.

    2016-01-01

    Nuclear receptors (NR) act as an integrated conduit for environmental and hormonal signals to govern genomic responses, which relate to cell fate decisions. We review how their integrated actions with each other, shared co-factors and other transcription factors are disrupted in cancer. Steroid hormone nuclear receptors are oncogenic drivers in breast and prostate cancer and blockade of signaling is a major therapeutic goal. By contrast to blockade of receptors, in other cancers enhanced receptor function is attractive, as illustrated initially with targeting of retinoic acid receptors in leukemia. In the post-genomic era large consortia, such as The Cancer Genome Atlas, have developed a remarkable volume of genomic data with which to examine multiple aspects of nuclear receptor status in a pan-cancer manner. Therefore to extend the review of NR function we have also undertaken bioinformatics analyses of NR expression in over 3000 tumors, spread across six different tumor types (bladder, breast, colon, head and neck, liver and prostate). Specifically, to ask how the NR expression was distorted (altered expression, mutation and CNV) we have applied bootstrapping approaches to simulate data for comparison, and also compared these NR findings to 12 other transcription factor families. Nuclear receptors were uniquely and uniformly downregulated across all six tumor types, more than predicted by chance. These approaches also revealed that each tumor type had a specific NR expression profile but these were most similar between breast and prostate cancer. Some NRs were down-regulated in at least five tumor types (e.g. NR3C2/MR and NR5A2/LRH-1)) whereas others were uniquely down-regulated in one tumor (e.g. NR1B3/RARG). The downregulation was not driven by copy number variation or mutation and epigenetic mechanisms maybe responsible for the altered nuclear receptor expression. PMID:27200367

  13. Pan-Cancer Analyses of the Nuclear Receptor Superfamily

    Directory of Open Access Journals (Sweden)

    Mark D. Long

    2015-12-01

    Full Text Available Nuclear receptors (NR act as an integrated conduit for environmental and hormonal signals to govern genomic responses, which relate to cell fate decisions. We review how their integrated actions with each other, shared co-factors and other transcription factors are disrupted in cancer. Steroid hormone nuclear receptors are oncogenic drivers in breast and prostate cancer and blockade of signaling is a major therapeutic goal. By contrast to blockade of receptors, in other cancers enhanced receptor function is attractive, as illustrated initially with targeting of retinoic acid receptors in leukemia. In the post-genomic era large consortia, such as The Cancer Genome Atlas, have developed a remarkable volume of genomic data with which to examine multiple aspects of nuclear receptor status in a pan-cancer manner. Therefore to extend the review of NR function we have also undertaken bioinformatics analyses of NR expression in over 3000 tumors, spread across six different tumor types (bladder, breast, colon, head and neck, liver and prostate. Specifically, to ask how the NR expression was distorted (altered expression, mutation and CNV we have applied bootstrapping approaches to simulate data for comparison, and also compared these NR findings to 12 other transcription factor families. Nuclear receptors were uniquely and uniformly downregulated across all six tumor types, more than predicted by chance. These approaches also revealed that each tumor type had a specific NR expression profile but these were most similar between breast and prostate cancer. Some NRs were down-regulated in at least five tumor types (e.g., NR3C2/MR and NR5A2/LRH-1 whereas others were uniquely down-regulated in one tumor (e.g., NR1B3/RARG. The downregulation was not driven by copy number variation or mutation and epigenetic mechanisms maybe responsible for the altered nuclear receptor expression.

  14. Identification and characterization of nucleolin as a COUP-TFII coactivator of retinoic acid receptor β transcription in breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Lacey M Litchfield

    Full Text Available INTRODUCTION: The orphan nuclear receptor COUP-TFII plays an undefined role in breast cancer. Previously we reported lower COUP-TFII expression in tamoxifen/endocrine-resistant versus sensitive breast cancer cell lines. The identification of COUP-TFII-interacting proteins will help to elucidate its mechanism of action as a transcriptional regulator in breast cancer. RESULTS: FLAG-affinity purification and multidimensional protein identification technology (MudPIT identified nucleolin among the proteins interacting with COUP-TFII in MCF-7 tamoxifen-sensitive breast cancer cells. Interaction of COUP-TFII and nucleolin was confirmed by coimmunoprecipitation of endogenous proteins in MCF-7 and T47D breast cancer cells. In vitro studies revealed that COUP-TFII interacts with the C-terminal arginine-glycine repeat (RGG domain of nucleolin. Functional interaction between COUP-TFII and nucleolin was indicated by studies showing that siRNA knockdown of nucleolin and an oligonucleotide aptamer that targets nucleolin, AS1411, inhibited endogenous COUP-TFII-stimulated RARB2 expression in MCF-7 and T47D cells. Chromatin immunoprecipitation revealed COUP-TFII occupancy of the RARB2 promoter was increased by all-trans retinoic acid (atRA. RARβ2 regulated gene RRIG1 was increased by atRA and COUP-TFII transfection and inhibited by siCOUP-TFII. Immunohistochemical staining of breast tumor microarrays showed nuclear COUP-TFII and nucleolin staining was correlated in invasive ductal carcinomas. COUP-TFII staining correlated with ERα, SRC-1, AIB1, Pea3, MMP2, and phospho-Src and was reduced with increased tumor grade. CONCLUSIONS: Our data indicate that nucleolin plays a coregulatory role in transcriptional regulation of the tumor suppressor RARB2 by COUP-TFII.

  15. Tyrosine phosphorylation of transcriptional coactivator WW-domain binding protein 2 regulates estrogen receptor α function in breast cancer via the Wnt pathway.

    Science.gov (United States)

    Lim, Shen Kiat; Orhant-Prioux, Magali; Toy, Weiyi; Tan, Kah Yap; Lim, Yoon Pin

    2011-09-01

    WW-binding protein 2 (WBP2) has been demonstrated in different studies to be a tyrosine kinase substrate, to activate estrogen receptor α (ERα)/progesterone receptor (PR) transcription, and to play a role in breast cancer. However, the role of WBP2 tyrosine phosphorylation in regulating ERα function and breast cancer biology is unknown. Here, we established WBP2 as a tyrosine phosphorylation target of estrogen signaling via EGFR crosstalk. Using dominant-negative, constitutively active mutants, RNAi, and pharmacological studies, we demonstrated that phosphorylation of WBP2 at Tyr192 and Tyr231 could be regulated by c-Src and c-Yes kinases. We further showed that abrogating WBP2 phosphorylation impaired >60% of ERα reporter activity, putatively by blocking nuclear entry of WBP2 and its interaction with ERα. Compared to vector control, overexpression of WBP2 and its phospho-mimic mutant in MCF7 cells resulted in larger tumors in mice, induced loss of cell-cell adhesion, and enhanced cell proliferation, anchorage-independent growth, migration, and invasion in both estrogen-dependent and -independent manners, events of which could be substantially abolished by overexpression of the phosphorylation-defective mutant. Hormone independence of cells expressing WBP2 phospho-mimic mutant was associated with heightened ERα and Wnt reporter activities. Wnt/β-catenin inhibitor FH535 blocked phospho-WBP2-mediated cancer cell growth more pronouncedly than tamoxifen and fulvestrant, in part by reducing the expression of ERα. Wnt pathway is likely to be a critical component in WBP2-mediated breast cancer biology.

  16. Genetic variation in the peroxisome proliferator-activated receptor (PPAR) and peroxisome proliferator-activated receptor gamma co-activator 1 (PGC1) gene families and type 2 diabetes.

    Science.gov (United States)

    Villegas, Raquel; Williams, Scott M; Gao, Yu-Tang; Long, Jirong; Shi, Jiajun; Cai, Hui; Li, Honglan; Chen, Ching-Chu; Tai, E Shyong; Hu, Frank; Cai, Qiuyin; Zheng, Wei; Shu, Xiao-Ou

    2014-01-01

    We used a two-stage study design to evaluate whether variations in the peroxisome proliferator-activated receptors (PPAR) and the PPAR gamma co-activator 1 (PGC1) gene families (PPARA, PPARG, PPARD, PPARGC1A, and PPARGC1B) are associated with type 2 diabetes (T2D) risk. Stage I used data from a genome-wide association study (GWAS) from Shanghai, China (1019 T2D cases and 1709 controls) and from a meta-analysis of data from the Asian Genetic Epidemiology Network for T2D (AGEN-T2D). Criteria for selection of single nucleotide polymorphisms (SNPs) for stage II were: (1) P < 0.05 in single marker analysis in Shanghai GWAS and P < 0.05 in the meta-analysis or (2) P < 10(-3) in the meta-analysis alone and (3) minor allele frequency ≥ 0.10. Nine SNPs from the PGC1 family were assessed in stage II (an independent set of middle-aged men and women from Shanghai with 1700 T2D cases and 1647 controls). One SNP in PPARGC1B, rs251464, was replicated in stage II (OR = 0.87; 95% CI: 0.77-0.99). Gene-body mass index (BMI) and gene-exercise interactions and T2D risk were evaluated in a combined dataset (Shanghai GWAS and stage II data: 2719 cases and 3356 controls). One SNP in PPARGC1A, rs12640088, had a significant interaction with BMI. No interactions between the PPARGC1B gene and BMI or exercise were observed. © 2013 John Wiley & Sons Ltd/University College London.

  17. Common polymorphisms of the peroxisome proliferator-activated receptor-gamma (Pro12Ala) and peroxisome proliferator-activated receptor-gamma coactivator-1 (Gly482Ser) and the response to pioglitazone in Chinese patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Hsieh, Ming-Chia; Lin, Kun-Der; Tien, Kai-Jen; Tu, Shih-Te; Hsiao, Jeng-Yueh; Chang, Shun-Jen; Lin, Shiu-Ru; Shing, Shih-Jang; Chen, Hung-Chun

    2010-08-01

    We investigated the effects of the common polymorphisms in the peroxisome proliferator-activated receptor-gamma (PPAR-gamma; Pro12Ala) and in PPAR-gamma coactivator-1(PGC-1; Gly482Ser) genes on the response to pioglitazone in Chinese with type 2 diabetes mellitus. A total of 250 patients with type 2 diabetes mellitus were treated with pioglitazone (30 mg/d) for 24 weeks without a change in previous medications. All patients were genotyped for the PPAR-gamma Pro12Ala and PGC-1 Gly482Ser polymorphisms. The Ala12Ala and Pro12Ala genotypes (26.0% vs 13.5%, P = .025) and Ala allele (15.6% vs 7.3%, P = .008) were significantly more frequent in pioglitazone responders than in nonresponders. The distribution of PGC-1 genotypes and alleles was not significantly different between responders and nonresponders. The decrease in fasting glucose (50.4 +/- 52.2 vs 43.3 +/- 51.7 mg/dL, P Pro12Ala and Ala12Ala) than in those without the allele (Pro12Pro). Baseline fasting glucose and triglyceride levels were related to the response of pioglitazone. Only the PPAR-gamma Pro12Ala polymorphism was found to be associated with the response of pioglitazone by multiple logistic regression analysis. The PPAR-gamma Pro12Ala gene polymorphism is associated with the response to pioglitazone in Chinese patients with type 2 diabetes mellitus. These findings may be helpful for targeted treatment of diabetes by identifying patients who are likely to respond to pioglitazone. Copyright 2010 Elsevier Inc. All rights reserved.

  18. Coregulator control of androgen receptor action by a novel nuclear receptor-binding motif.

    Science.gov (United States)

    Jehle, Katja; Cato, Laura; Neeb, Antje; Muhle-Goll, Claudia; Jung, Nicole; Smith, Emmanuel W; Buzon, Victor; Carbó, Laia R; Estébanez-Perpiñá, Eva; Schmitz, Katja; Fruk, Ljiljana; Luy, Burkhard; Chen, Yu; Cox, Marc B; Bräse, Stefan; Brown, Myles; Cato, Andrew C B

    2014-03-28

    The androgen receptor (AR) is a ligand-activated transcription factor that is essential for prostate cancer development. It is activated by androgens through its ligand-binding domain (LBD), which consists predominantly of 11 α-helices. Upon ligand binding, the last helix is reorganized to an agonist conformation termed activator function-2 (AF-2) for coactivator binding. Several coactivators bind to the AF-2 pocket through conserved LXXLL or FXXLF sequences to enhance the activity of the receptor. Recently, a small compound-binding surface adjacent to AF-2 has been identified as an allosteric modulator of the AF-2 activity and is termed binding function-3 (BF-3). However, the role of BF-3 in vivo is currently unknown, and little is understood about what proteins can bind to it. Here we demonstrate that a duplicated GARRPR motif at the N terminus of the cochaperone Bag-1L functions through the BF-3 pocket. These findings are supported by the fact that a selective BF-3 inhibitor or mutations within the BF-3 pocket abolish the interaction between the GARRPR motif(s) and the BF-3. Conversely, amino acid exchanges in the two GARRPR motifs of Bag-1L can impair the interaction between Bag-1L and AR without altering the ability of Bag-1L to bind to chromatin. Furthermore, the mutant Bag-1L increases androgen-dependent activation of a subset of AR targets in a genome-wide transcriptome analysis, demonstrating a repressive function of the GARRPR/BF-3 interaction. We have therefore identified GARRPR as a novel BF-3 regulatory sequence important for fine-tuning the activity of the AR.

  19. Cardiac nuclear receptors: architects of mitochondrial structure and function.

    Science.gov (United States)

    Vega, Rick B; Kelly, Daniel P

    2017-04-03

    The adult heart is uniquely designed and equipped to provide a continuous supply of energy in the form of ATP to support persistent contractile function. This high-capacity energy transduction system is the result of a remarkable surge in mitochondrial biogenesis and maturation during the fetal-to-adult transition in cardiac development. Substantial evidence indicates that nuclear receptor signaling is integral to dynamic changes in the cardiac mitochondrial phenotype in response to developmental cues, in response to diverse postnatal physiologic conditions, and in disease states such as heart failure. A subset of cardiac-enriched nuclear receptors serve to match mitochondrial fuel preferences and capacity for ATP production with changing energy demands of the heart. In this Review, we describe the role of specific nuclear receptors and their coregulators in the dynamic control of mitochondrial biogenesis and energy metabolism in the normal and diseased heart.

  20. Research progress in peroxisome proliferator-activated receptor γ coactivator-1α%过氧化物酶体增殖物激活受体γ辅激活因子1α的研究进展

    Institute of Scientific and Technical Information of China (English)

    王喜

    2012-01-01

    In eukaryotes,cellular and systemic metabolism is primarily controlled by mitochondrial activity. The peroxisome proliferator-activated receptor γ coactivator la (PGC-lα) is an important regulator of mitochondrial biogenesis and function. There is currently much interest in PGC-la, focusing on two important characteristics: tissue-specific expression and induction of a specific signal. PGC-la is expressed at high levels in tissues where mitochondria are abundant and oxidative metabolism is active. The signal induction activity of PGC-la is clearly related to the cell's energy metabolism state. For example, cold, fasting and exercise all contribute to a increase in PGC-la expression.%在真核生物中,细胞和组织的能量代谢主要是由线粒体控制,而过氧化物酶体增殖物激活受体γ辅激活因子1α(peroxisome proliferator-activated receptorγ coactivator-1α,PGC-1α)在线粒体的生物合成和功能中起着重要的调控作用.PGC-1α有两个重要特征,即组织表达特异性和信号诱导特异性.组织特异性主要表现在高表达于线粒体丰富和氧化代谢活跃的组织中,而其信号诱导特异性表现在PGC-1α的表达主要受能量代谢需要的影响,如寒冷、禁食及运动均促进PGC-1α的表达.

  1. Nuclear transportation of exogenous epidermal growth factor receptor and androgen receptor via extracellular vesicles.

    Science.gov (United States)

    Read, Jolene; Ingram, Alistair; Al Saleh, Hassan A; Platko, Khrystyna; Gabriel, Kathleen; Kapoor, Anil; Pinthus, Jehonathan; Majeed, Fadwa; Qureshi, Talha; Al-Nedawi, Khalid

    2017-01-01

    Epidermal growth factor receptor (EGFR) plays a central role in the progression of several human malignancies. Although EGFR is a membrane receptor, it undergoes nuclear translocation, where it has a distinct signalling pathway. Herein, we report a novel mechanism by which cancer cells can directly transport EGFR to the nucleus of other cells via extracellular vesicles (EVs). The transported receptor is active and stimulates the nuclear EGFR pathways. Interestingly, the translocation of EGFR via EVs occurs independently of the nuclear localisation sequence that is required for nuclear translocation of endogenous EGFR. Also, we found that the mutant receptor EGFRvIII could be transported to the nucleus of other cells via EVs. To assess the role of EVs in the regulation of an actual nuclear receptor, we studied the regulation of androgen receptor (AR). We found that full-length AR and mutant variant ARv7 are secreted in EVs derived from prostate cancer cell lines and could be transported to the nucleus of AR-null cells. The EV-derived AR was able to bind the androgen-responsive promoter region of prostate specific antigen, and recruit RNA Pol II, an indication of active transcription. The nuclear-translocated AR via EVs enhanced the proliferation of acceptor cells in the absence of androgen. Finally, we provide evidence that nuclear localisation of AR could occur in vivo via orthotopically-injected EVs in male SCID mice prostate glands. To our knowledge, this is the first study showing the nuclear translocation of nuclear receptors via EVs, which significantly extends the role of EVs as paracrine transcriptional regulators.

  2. TBLR1 as an AR coactivator selectively activates AR target genes to inhibit prostate cancer growth

    Science.gov (United States)

    Daniels, Garrett; Li, Yirong; Gellert, Lan Lin; Zhou, Albert; Melamed, Jonathan; Wu, Xinyu; Zhang, Xinming; Zhang, David; Meruelo, Daniel; Logan, Susan K.; Basch, Ross; Lee, Peng

    2014-01-01

    Androgen Receptor (AR), a steroid hormone receptor, is critical for prostate cancer growth. However, activation of AR by androgens can also lead to growth suppression and differentiation. Transcriptional cofactors play an important role in this switch between proliferative and anti-proliferative AR target gene programs. TBLR1, a core component of the nuclear receptor corepressor (NCoR) complex, shows both co-repressor and co-activator activities on nuclear receptors, but little is known about its effects on AR and prostate cancer. We characterized TBLR1 as a coactivator of AR in prostate cancer cells and the activation is both phosphorylation and 19S proteosome dependent. We showed that TBLR1 physically interacts with AR and directly occupies the androgen response elements of affected AR target genes in an androgen-dependent manner. TBLR1 is primarily localized in the nucleus in benign prostate cells and nuclear expression is significantly reduced in prostate cancer cells in culture. Similarly, in human tumor samples, the expression of TBLR1 in the nucleus is significantly reduced in the malignant glands compared to the surrounding benign prostatic glands (p<0.005). Stable ectopic expression of nuclear TBLR1 leads to androgen-dependent growth suppression of prostate cancer cells in vitro and in vivo by selective activation of androgen regulated genes associated with differentiation (e.g. KRT18) and growth suppression (e.g. NKX3.1), but not cell proliferation of the prostate. Understanding the molecular switches involved in the transition from AR dependent growth promotion to AR dependent growth suppression will lead to more successful prostate cancer treatments. PMID:24243687

  3. Elevated copper impairs hepatic nuclear receptor function in Wilson's disease.

    Science.gov (United States)

    Wooton-Kee, Clavia Ruth; Jain, Ajay K; Wagner, Martin; Grusak, Michael A; Finegold, Milton J; Lutsenko, Svetlana; Moore, David D

    2015-09-01

    Wilson's disease (WD) is an autosomal recessive disorder that results in accumulation of copper in the liver as a consequence of mutations in the gene encoding the copper-transporting P-type ATPase (ATP7B). WD is a chronic liver disorder, and individuals with the disease present with a variety of complications, including steatosis, cholestasis, cirrhosis, and liver failure. Similar to patients with WD, Atp7b⁻/⁻ mice have markedly elevated levels of hepatic copper and liver pathology. Previous studies have demonstrated that replacement of zinc in the DNA-binding domain of the estrogen receptor (ER) with copper disrupts specific binding to DNA response elements. Here, we found decreased binding of the nuclear receptors FXR, RXR, HNF4α, and LRH-1 to promoter response elements and decreased mRNA expression of nuclear receptor target genes in Atp7b⁻/⁻ mice, as well as in adult and pediatric WD patients. Excessive hepatic copper has been described in progressive familial cholestasis (PFIC), and we found that similar to individuals with WD, patients with PFIC2 or PFIC3 who have clinically elevated hepatic copper levels exhibit impaired nuclear receptor activity. Together, these data demonstrate that copper-mediated nuclear receptor dysfunction disrupts liver function in WD and potentially in other disorders associated with increased hepatic copper levels.

  4. Nuclear tristetraprolin acts as a corepressor of multiple steroid nuclear receptors in breast cancer cells

    Directory of Open Access Journals (Sweden)

    Tonatiuh Barrios-García

    2016-06-01

    Full Text Available Tristetraprolin (TTP is a 34-kDa, zinc finger-containing factor that in mammalian cells acts as a tumor suppressor protein through two different mechanisms. In the cytoplasm TTP promotes the decay of hundreds of mRNAs encoding cell factors involved in inflammation, tissue invasion, and metastasis. In the cell nucleus TTP has been identified as a transcriptional corepressor of the estrogen receptor alpha (ERα, which has been associated to the development and progression of the majority of breast cancer tumors. In this work we report that nuclear TTP modulates the transactivation activity of progesterone receptor (PR, glucocorticoid receptor (GR and androgen receptor (AR. In recent years these steroid nuclear receptors have been shown to be of clinical and therapeutical relevance in breast cancer. The functional association between TTP and steroid nuclear receptors is supported by the finding that TTP physically interacts with ERα, PR, GR and AR in vivo. We also show that TTP overexpression attenuates the transactivation of all the steroid nuclear receptors tested. In contrast, siRNA-mediated reduction of endogenous TTP expression in MCF-7 cells produced an increase in the transcriptional activities of ERα, PR, GR and AR. Taken together, these results suggest that the function of nuclear TTP in breast cancer cells is to act as a corepressor of ERα, PR, GR and AR. We propose that the reduction of TTP expression observed in different types of breast cancer tumors may contribute to the development of this disease by producing a dysregulation of the transactivation activity of multiple steroid nuclear receptors.

  5. Review: Receptor Targeted Nuclear Imaging of Breast Cancer.

    Science.gov (United States)

    Dalm, Simone U; Verzijlbergen, John Fred; De Jong, Marion

    2017-01-26

    Receptor targeted nuclear imaging directed against molecular markers overexpressed on breast cancer (BC) cells offers a sensitive and specific method for BC imaging. Currently, a few targets such as estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), somatostatin receptor (SSTR), and the gastrin releasing peptide receptor (GRPR) are being investigated for this purpose. Expression of these targets is BC subtype dependent and information that can be gained from lesion visualization is dependent on the target; ER-targeting radiotracers, e.g., can be used to monitor response to anti-estrogen treatment. Here we give an overview of the studies currently under investigation for receptor targeted nuclear imaging of BC. Main findings of imaging studies are summarized and (potential) purposes of lesion visualization by targeting these molecular markers are discussed. Since BC is a very heterogeneous disease and molecular target expression can vary per subtype, but also during disease progression or under influence of treatment, radiotracers for selected imaging purposes should be chosen carefully.

  6. Review: Receptor Targeted Nuclear Imaging of Breast Cancer

    Science.gov (United States)

    Dalm, Simone U.; Verzijlbergen, John Fred; De Jong, Marion

    2017-01-01

    Receptor targeted nuclear imaging directed against molecular markers overexpressed on breast cancer (BC) cells offers a sensitive and specific method for BC imaging. Currently, a few targets such as estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), somatostatin receptor (SSTR), and the gastrin releasing peptide receptor (GRPR) are being investigated for this purpose. Expression of these targets is BC subtype dependent and information that can be gained from lesion visualization is dependent on the target; ER-targeting radiotracers, e.g., can be used to monitor response to anti-estrogen treatment. Here we give an overview of the studies currently under investigation for receptor targeted nuclear imaging of BC. Main findings of imaging studies are summarized and (potential) purposes of lesion visualization by targeting these molecular markers are discussed. Since BC is a very heterogeneous disease and molecular target expression can vary per subtype, but also during disease progression or under influence of treatment, radiotracers for selected imaging purposes should be chosen carefully. PMID:28134770

  7. Nuclear receptor corepressor-dependent repression of peroxisome-proliferator-activated receptor delta-mediated transactivation

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Nielsen, Curt A F; Neve, Søren

    2002-01-01

    delta-RXR alpha heterodimer bound to an acyl-CoA oxidase (ACO)-type peroxisome-proliferator response element recruited a glutathione S-transferase-NCoR fusion protein in a ligand-independent manner. Contrasting with most other nuclear receptors, PPAR delta was found to interact equally well......The nuclear receptor corepressor (NCoR) was isolated as a peroxisome-proliferator-activated receptor (PPAR) delta interacting protein using the yeast two-hybrid system. NCoR interacted strongly with the ligand-binding domain of PPAR delta, whereas interactions with the ligand-binding domains...

  8. Nuclear receptor corepressor-dependent repression of peroxisome-proliferator-activated receptor delta-mediated transactivation

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Nielsen, Curt A F; Neve, Søren

    2002-01-01

    delta-RXR alpha heterodimer bound to an acyl-CoA oxidase (ACO)-type peroxisome-proliferator response element recruited a glutathione S-transferase-NCoR fusion protein in a ligand-independent manner. Contrasting with most other nuclear receptors, PPAR delta was found to interact equally well......The nuclear receptor corepressor (NCoR) was isolated as a peroxisome-proliferator-activated receptor (PPAR) delta interacting protein using the yeast two-hybrid system. NCoR interacted strongly with the ligand-binding domain of PPAR delta, whereas interactions with the ligand-binding domains...

  9. Nuclear receptors : mediators and modifiers of inflammation-induced cholestasis

    NARCIS (Netherlands)

    Mulder, Jaap; Karpen, Saul J.; Tietge, Uwe J. F.; Kuipers, Folkert

    2009-01-01

    Inflammation-induced cholestasis (IIC) is a frequently occurring phenomenon. A central role in its pathogenesis is played by nuclear receptors (NRs). These ligand-activated transcription factors not only regulate basal expression of hepatobiliary transport systems, but also mediate adaptive response

  10. NucleaRDB: information system for nuclear receptors.

    NARCIS (Netherlands)

    Vroling, B.; Thorne, D.; McDermott, P.; Joosten, H.J.; Attwood, T.K.; Pettifer, S.; Vriend, G.

    2012-01-01

    The NucleaRDB is a Molecular Class-Specific Information System that collects, combines, validates and disseminates large amounts of heterogeneous data on nuclear hormone receptors. It contains both experimental and computationally derived data. The data and knowledge present in the NucleaRDB can be

  11. NucleaRDB: information system for nuclear receptors.

    NARCIS (Netherlands)

    Vroling, B.; Thorne, D.; McDermott, P.; Joosten, H.J.; Attwood, T.K.; Pettifer, S.; Vriend, G.

    2012-01-01

    The NucleaRDB is a Molecular Class-Specific Information System that collects, combines, validates and disseminates large amounts of heterogeneous data on nuclear hormone receptors. It contains both experimental and computationally derived data. The data and knowledge present in the NucleaRDB can be

  12. The Gly482Ser Missense Mutation of the Peroxisome Proliferator-Activated Receptor γ Coactivator-1α (PGC-1α Gene Associates with Reduced Insulin Sensitivity in Normal and Glucose-Intolerant Obese Subjects

    Directory of Open Access Journals (Sweden)

    Marzia Fanelli

    2005-01-01

    Full Text Available Among the putative candidate genes for insulin resistance, the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α is a transcriptional coactivator of PPARγ and α, regulating a wide range of processes involved in energy production and utilization, such as thermogenesis, liver gluconeogenesis, glucose uptake in muscle. In population studies a Gly482Ser substitution in PGC-1α has been reported to be associated with increased risk of type diabetes 2 and insulin resistance. In the present study we have analysed the association between the Gly482Ser missense mutation of the PGC-1α gene and insulin sensitivity and glucose tolerance in a population of obese non-diabetic subjects. The Gly482Ser SNPs was detected by PCR-RFLP in a cohort of 358 Caucasian obese subjects (223 with normal glucose tolerance (NGT and 125 with impaired glucose tolerance (IGT. We observed a significant association (p < 0.007 between carriers of the Gly482Ser variant of the PGC-1α gene and insulin resistance measured by HOMAIR. Multivariate analysis confirmed that the Gly482Ser SNP was a significant (p < 0.02 determinant of decreased insulin sensitivity, independently from other well-known modulators of insulin action. In conclusion, we have found significant association between the Gly482Ser variant of the PGC-1α gene and reduced insulin sensitivity in obese subjects. This association resulted independent from all other known modulators of insulin resistance, and suggests a primary role for the PGC-1α gene on the genetic susceptibility to insulin resistance in obesity.

  13. Coexpression of nuclear receptors and histone methylation modifying genes in the testis: implications for endocrine disruptor modes of action.

    Directory of Open Access Journals (Sweden)

    Alison M Anderson

    Full Text Available BACKGROUND: Endocrine disruptor chemicals elicit adverse health effects by perturbing nuclear receptor signalling systems. It has been speculated that these compounds may also perturb epigenetic mechanisms and thus contribute to the early origin of adult onset disease. We hypothesised that histone methylation may be a component of the epigenome that is susceptible to perturbation. We used coexpression analysis of publicly available data to investigate the combinatorial actions of nuclear receptors and genes involved in histone methylation in normal testis and when faced with endocrine disruptor compounds. METHODOLOGY/PRINCIPAL FINDINGS: The expression patterns of a set of genes were profiled across testis tissue in human, rat and mouse, plus control and exposed samples from four toxicity experiments in the rat. Our results indicate that histone methylation events are a more general component of nuclear receptor mediated transcriptional regulation in the testis than previously appreciated. Coexpression patterns support the role of a gatekeeper mechanism involving the histone methylation modifiers Kdm1, Prdm2, and Ehmt1 and indicate that this mechanism is a common determinant of transcriptional integrity for genes critical to diverse physiological endpoints relevant to endocrine disruption. Coexpression patterns following exposure to vinclozolin and dibutyl phthalate suggest that coactivity of the demethylase Kdm1 in particular warrants further investigation in relation to endocrine disruptor mode of action. CONCLUSIONS/SIGNIFICANCE: This study provides proof of concept that a bioinformatics approach that profiles genes related to a specific hypothesis across multiple biological settings can provide powerful insight into coregulatory activity that would be difficult to discern at an individual experiment level or by traditional differential expression analysis methods.

  14. The role of mitogen-activated protein kinases and sterol receptor coactivator-1 in TGF-β-regulated expression of genes implicated in macrophage cholesterol uptake

    Science.gov (United States)

    Salter, Rebecca C.; Foka, Pelagia; Davies, Thomas S.; Gallagher, Hayley; Michael, Daryn R.; Ashlin, Tim G.; Ramji, Dipak P.

    2016-01-01

    The anti-atherogenic cytokine TGF-β inhibits macrophage foam cell formation by suppressing the expression of key genes implicated in the uptake of modified lipoproteins. We have previously shown a critical role for p38 MAPK and JNK in the TGF-β-mediated regulation of apolipoprotein E expression in human monocytes. However, the roles of these two MAPK pathways in the control of expression of key genes involved in the uptake of modified lipoproteins in human macrophages is poorly understood and formed the focus of this study. TGF-β activated both p38 MAPK and JNK, and knockdown of p38 MAPK or c-Jun, a key downstream target of JNK action, demonstrated their requirement in the TGF-β-inhibited expression of several key genes implicated in macrophage lipoprotein uptake. The potential role of c-Jun and specific co-activators in the action of TGF-β was investigated further by studies on the lipoprotein lipase gene. c-Jun did not directly interact with the minimal promoter region containing the TGF-β response elements and a combination of transient transfection and knock down assays revealed an important role for SRC-1. These studies provide novel insights into the mechanisms underlying the TGF-β-mediated inhibition of macrophage gene expression associated with the control of cholesterol homeostasis. PMID:27687241

  15. The role of mitogen-activated protein kinases and sterol receptor coactivator-1 in TGF-β-regulated expression of genes implicated in macrophage cholesterol uptake.

    Science.gov (United States)

    Salter, Rebecca C; Foka, Pelagia; Davies, Thomas S; Gallagher, Hayley; Michael, Daryn R; Ashlin, Tim G; Ramji, Dipak P

    2016-09-30

    The anti-atherogenic cytokine TGF-β inhibits macrophage foam cell formation by suppressing the expression of key genes implicated in the uptake of modified lipoproteins. We have previously shown a critical role for p38 MAPK and JNK in the TGF-β-mediated regulation of apolipoprotein E expression in human monocytes. However, the roles of these two MAPK pathways in the control of expression of key genes involved in the uptake of modified lipoproteins in human macrophages is poorly understood and formed the focus of this study. TGF-β activated both p38 MAPK and JNK, and knockdown of p38 MAPK or c-Jun, a key downstream target of JNK action, demonstrated their requirement in the TGF-β-inhibited expression of several key genes implicated in macrophage lipoprotein uptake. The potential role of c-Jun and specific co-activators in the action of TGF-β was investigated further by studies on the lipoprotein lipase gene. c-Jun did not directly interact with the minimal promoter region containing the TGF-β response elements and a combination of transient transfection and knock down assays revealed an important role for SRC-1. These studies provide novel insights into the mechanisms underlying the TGF-β-mediated inhibition of macrophage gene expression associated with the control of cholesterol homeostasis.

  16. Screening and association testing of common coding variation in steroid hormone receptor co-activator and co-repressor genes in relation to breast cancer risk: the Multiethnic Cohort

    Directory of Open Access Journals (Sweden)

    Stallcup Michael R

    2009-01-01

    Full Text Available Abstract Background Only a limited number of studies have performed comprehensive investigations of coding variation in relation to breast cancer risk. Given the established role of estrogens in breast cancer, we hypothesized that coding variation in steroid receptor coactivator and corepressor genes may alter inter-individual response to estrogen and serve as markers of breast cancer risk. Methods We sequenced the coding exons of 17 genes (EP300, CCND1, NME1, NCOA1, NCOA2, NCOA3, SMARCA4, SMARCA2, CARM1, FOXA1, MPG, NCOR1, NCOR2, CALCOCO1, PRMT1, PPARBP and CREBBP suggested to influence transcriptional activation by steroid hormone receptors in a multiethnic panel of women with advanced breast cancer (n = 95: African Americans, Latinos, Japanese, Native Hawaiians and European Americans. Association testing of validated coding variants was conducted in a breast cancer case-control study (1,612 invasive cases and 1,961 controls nested in the Multiethnic Cohort. We used logistic regression to estimate odds ratios for allelic effects in ethnic-pooled analyses as well as in subgroups defined by disease stage and steroid hormone receptor status. We also investigated effect modification by established breast cancer risk factors that are associated with steroid hormone exposure. Results We identified 45 coding variants with frequencies ≥ 1% in any one ethnic group (43 non-synonymous variants. We observed nominally significant positive associations with two coding variants in ethnic-pooled analyses (NCOR2: His52Arg, OR = 1.79; 95% CI, 1.05–3.05; CALCOCO1: Arg12His, OR = 2.29; 95% CI, 1.00–5.26. A small number of variants were associated with risk in disease subgroup analyses and we observed no strong evidence of effect modification by breast cancer risk factors. Based on the large number of statistical tests conducted in this study, the nominally significant associations that we observed may be due to chance, and will need to be confirmed in other

  17. DMPD: Nuclear receptor signaling in macrophages. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14698033 Nuclear receptor signaling in macrophages. Valledor AF, Ricote M. Biochem ...Pharmacol. 2004 Jan 15;67(2):201-12. (.png) (.svg) (.html) (.csml) Show Nuclear receptor signaling in macrop...hages. PubmedID 14698033 Title Nuclear receptor signaling in macrophages. Authors Valledor AF, Ricote M. Pub

  18. Validation of a new yeast-based reporter assay consisting of human estrogen receptors alpha/beta and coactivator SRC-1: application for detection of estrogenic activity in environmental samples.

    Science.gov (United States)

    Chu, Wai-Ling; Shiizaki, Kazuhiro; Kawanishi, Masanobu; Kondo, Mami; Yagi, Takashi

    2009-10-01

    Endocrine disruptors are exogenous substances that act like hormones in the endocrine system and disrupt the physiologic function of endogenous hormones. In the present study, we established reporter yeast strains (Saccharomyces cerevisiae) expressing human estrogen receptors, ERalpha or ERbeta. These strains contain a reporter plasmid carrying an estrogen responsive element (ERE) upstream of the beta-galactosidase gene, and a plasmid expressing a steroid receptor coactivator, SRC-1e. Using these reporter strains, we demonstrated dose-dependent estrogenic activities of different categories of ligands, a natural hormone, 17beta-estradiol (E2); a synthetic drug, diethylstilbestrol (DES); phytoestrogens, genistein, daizein and emodin; and an environmental endocrine disrupter, bisphenol A. EC(50) values of E2 for ERalpha and ERbeta are 5.31 x 10(-10) and 5.85 x 10(-10) M, respectively. We also demonstrated that these yeasts were applicable for measuring estrogenic activities of environmental water samples. Most downstream sites of a river showed similar activity in both ERalpha and ERbeta assays. These yeast strains are useful and convenient for detecting and comparing the estrogenic ligand activities of environmental samples in response to ERalpha and ERbeta.

  19. Endothelial nuclear lamina is not required for glucocorticoid receptor nuclear import but does affect receptor-mediated transcription activation.

    Science.gov (United States)

    Nayebosadri, Arman; Ji, Julie Y

    2013-08-01

    The lamina serves to maintain the nuclear structure and stiffness while acting as a scaffold for heterochromatin and many transcriptional proteins. Its role in endothelial mechanotransduction, specifically how nuclear mechanics impact gene regulation under shear stress, is not fully understood. In this study, we successfully silenced lamin A/C in bovine aortic endothelial cells to determine its role in both glucocorticoid receptor (GR) nuclear translocation and glucocorticoid response element (GRE) transcriptional activation in response to dexamethasone and shear stress. Nuclear translocation of GR, an anti-inflammatory nuclear receptor, in response to dexamethasone or shear stress (5, 10, and 25 dyn/cm(2)) was observed via time-lapse cell imaging and quantified using a Bayesian image analysis algorithm. Transcriptional activity of the GRE promoter was assessed using a dual-luciferase reporter plasmid. We found no dependence on nuclear lamina for GR translocation from the cytoplasm into the nucleus. However, the absence of lamin A/C led to significantly increased expression of luciferase under dexamethasone and shear stress induction as well as changes in histone protein function. PCR results for NF-κB inhibitor alpha (NF-κBIA) and dual specificity phosphatase 1 (DUSP1) genes further supported our luciferase data with increased expression in the absence of lamin. Our results suggest that absence of lamin A/C does not hinder passage of GR into the nucleus, but nuclear lamina is important to properly regulate GRE transcription. Nuclear lamina, rather than histone deacetylase (HDAC), is a more significant mediator of shear stress-induced transcriptional activity, while dexamethasone-initiated transcription is more HDAC dependent. Our findings provide more insights into the molecular pathways involved in nuclear mechanotransduction.

  20. Identification of a putative nuclear localization sequence within ANG II AT(1A) receptor associated with nuclear activation.

    Science.gov (United States)

    Morinelli, Thomas A; Raymond, John R; Baldys, Aleksander; Yang, Qing; Lee, Mi-Hye; Luttrell, Louis; Ullian, Michael E

    2007-04-01

    Angiotensin II (ANG II) type 1 (AT(1)) receptors, similar to other G protein-coupled receptors, undergo desensitization and internalization, and potentially nuclear localization, subsequent to agonist interaction. Evidence suggests that the carboxy-terminal tail may be involved in receptor nuclear localization. In the present study, we examined the carboxy-terminal tail of the receptor for specific regions responsible for the nuclear translocation phenomenon and resultant nuclear activation. Human embryonic kidney cells stably expressing either a wild-type AT(1A) receptor-green fluorescent protein (AT(1A)R/GFP) construct or a site-directed mutation of a putative nuclear localization sequence (NLS) [K307Q]AT(1A)R/GFP (KQ/AT(1A)R/GFP), were examined for differences in receptor nuclear trafficking and nuclear activation. Receptor expression, intracellular signaling, and ANG II-induced internalization of the wild-type/GFP construct and of the KQ/AT(1A)R/GFP mutant was similar. Laser scanning confocal microscopy showed that in cells expressing the AT(1A)R/GFP, trafficking of the receptor to the nuclear area and colocalization with lamin B occurred within 30 min of ANG II (100 nM) stimulation, whereas the KQ/AT(1A)R/GFP mutant failed to demonstrate nuclear localization. Immunoblotting of nuclear lysates with an anti-GFP antibody confirmed these observations. Nuclear localization of the wild-type receptor correlated with increase transcription for both EGR-1 and PTGS-2 genes while the nuclear-deficient KQ/AT(1A)R/GFP mutant demonstrated increases for only the EGR-1 gene. These results suggest that a NLS (KKFKKY; aa307-312) is located within the cytoplasmic tail of the AT(1A) receptor and that nuclear localization of the receptor corresponds with specific activation of transcription for the COX-2 gene PTGS-2.

  1. Coordinate regulation of lipid metabolism by novel nuclear receptor partnerships.

    Directory of Open Access Journals (Sweden)

    Pranali P Pathare

    Full Text Available Mammalian nuclear receptors broadly influence metabolic fitness and serve as popular targets for developing drugs to treat cardiovascular disease, obesity, and diabetes. However, the molecular mechanisms and regulatory pathways that govern lipid metabolism remain poorly understood. We previously found that the Caenorhabditis elegans nuclear hormone receptor NHR-49 regulates multiple genes in the fatty acid beta-oxidation and desaturation pathways. Here, we identify additional NHR-49 targets that include sphingolipid processing and lipid remodeling genes. We show that NHR-49 regulates distinct subsets of its target genes by partnering with at least two other distinct nuclear receptors. Gene expression profiles suggest that NHR-49 partners with NHR-66 to regulate sphingolipid and lipid remodeling genes and with NHR-80 to regulate genes involved in fatty acid desaturation. In addition, although we did not detect a direct physical interaction between NHR-49 and NHR-13, we demonstrate that NHR-13 also regulates genes involved in the desaturase pathway. Consistent with this, gene knockouts of these receptors display a host of phenotypes that reflect their gene expression profile. Our data suggest that NHR-80 and NHR-13's modulation of NHR-49 regulated fatty acid desaturase genes contribute to the shortened lifespan phenotype of nhr-49 deletion mutant animals. In addition, we observed that nhr-49 animals had significantly altered mitochondrial morphology and function, and that distinct aspects of this phenotype can be ascribed to defects in NHR-66- and NHR-80-mediated activities. Identification of NHR-49's binding partners facilitates a fine-scale dissection of its myriad regulatory roles in C. elegans. Our findings also provide further insights into the functions of the mammalian lipid-sensing nuclear receptors HNF4α and PPARα.

  2. Transmembrane helices in "classical" nuclear reproductive steroid receptors: a perspective.

    Science.gov (United States)

    Morrill, Gene A; Kostellow, Adele B; Gupta, Raj K

    2015-01-01

    Steroid receptors of the nuclear receptor superfamily are proposed to be either: 1) located in the cytosol and moved to the cell nucleus upon activation, 2) tethered to the inside of the plasma membrane, or 3) retained in the nucleus until free steroid hormone enters and activates specific receptors. Using computational methods to analyze peptide receptor topology, we find that the "classical" nuclear receptors for progesterone (PRB/PGR), androgen (ARB/AR) and estrogen (ER1/ESR1) contain two transmembrane helices (TMH) within their ligand-binding domains (LBD).The MEMSAT-SVM algorithm indicates that ARB and ER2 (but not PRB or ER1) contain a pore-lining (channel-forming) region which may merge with other pore-lining regions to form a membrane channel. ER2 lacks a TMH, but contains a single pore-lining region. The MemBrain algorithm predicts that PRB, ARB and ER1 each contain one TMH plus a half TMH separated by 51 amino acids.ER2 contains two half helices. The TM-2 helices of ARB, ER1 and ER2 each contain 9-13 amino acid motifs reported to translocate the receptor to the plasma membrane, as well as cysteine palmitoylation sites. PoreWalker analysis of X-ray crystallographic data identifies a pore or channel within the LBDs of ARB and ER1 and predicts that 70 and 72 residues are pore-lining residues, respectively. The data suggest that (except for ER2), cytosolic receptors become anchored to the plasma membrane following synthesis. Half-helices and pore-lining regions in turn form functional ion channels and/or facilitate passive steroid uptake into the cell. In perspective, steroid-dependent insertion of "classical" receptors containing pore-lining regions into the plasma membrane may regulate permeability to ions such as Ca(2+), Na(+) or K(+), as well as facilitate steroid translocation into the nucleus.

  3. Nuclear hormone receptor co-repressors: Structure and function

    OpenAIRE

    2012-01-01

    Co-repressor proteins, such as SMRT and NCoR, mediate the repressive activity of unliganded nuclear receptors and other transcription factors. They appear to act as intrinsically disordered “hub proteins” that integrate the activities of a range of transcription factors with a number of histone modifying enzymes. Although these co-repressor proteins are challenging targets for structural studies due to their largely unstructured character, a number of structures have recently been determined ...

  4. Atypical nuclear localization of VIP receptors in glioma cell lines and patients

    Energy Technology Data Exchange (ETDEWEB)

    Barbarin, Alice; Séité, Paule [Equipe Récepteurs, Régulations et Cellules Tumorales, Université de Poitiers, PBS bât 36, 1 rue Georges Bonnet, TSA 51106, 86073 Poitiers Cedex 9 (France); Godet, Julie [Laboratoire d’anatomie et de cytologie pathologiques, CHU de Poitiers, 2 rue de la Milétrie, 86000 Poitiers (France); Bensalma, Souheyla; Muller, Jean-Marc [Equipe Récepteurs, Régulations et Cellules Tumorales, Université de Poitiers, PBS bât 36, 1 rue Georges Bonnet, TSA 51106, 86073 Poitiers Cedex 9 (France); Chadéneau, Corinne, E-mail: corinne.chadeneau@univ-poitiers.fr [Equipe Récepteurs, Régulations et Cellules Tumorales, Université de Poitiers, PBS bât 36, 1 rue Georges Bonnet, TSA 51106, 86073 Poitiers Cedex 9 (France)

    2014-11-28

    Highlights: • The VIP receptor VPAC1 contains a putative NLS signal. • VPAC1 is predominantly nuclear in GBM cell lines but not VPAC2. • Non-nuclear VPAC1/2 protein expression is correlated with glioma grade. • Nuclear VPAC1 is observed in 50% of stage IV glioma (GBM). - Abstract: An increasing number of G protein-coupled receptors, like receptors for vasoactive intestinal peptide (VIP), are found in cell nucleus. As VIP receptors are involved in the regulation of glioma cell proliferation and migration, we investigated the expression and the nuclear localization of the VIP receptors VPAC1 and VPAC2 in this cancer. First, by applying Western blot and immunofluorescence detection in three human glioblastoma (GBM) cell lines, we observed a strong nuclear staining for the VPAC1 receptor and a weak nuclear VPAC2 receptor staining. Second, immunohistochemical staining of VPAC1 and VPAC2 on tissue microarrays (TMA) showed that the two receptors were expressed in normal brain and glioma tissues. Expression in the non-nuclear compartment of the two receptors significantly increased with the grade of the tumors. Analysis of nuclear staining revealed a significant increase of VPAC1 staining with glioma grade, with up to 50% of GBM displaying strong VPAC1 nuclear staining, whereas nuclear VPAC2 staining remained marginal. The increase in VPAC receptor expression with glioma grades and the enhanced nuclear localization of the VPAC1 receptors in GBM might be of importance for glioma progression.

  5. A Comprehensive Nuclear Receptor Network for Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ralf Kittler

    2013-02-01

    Full Text Available In breast cancer, nuclear receptors (NRs play a prominent role in governing gene expression, have prognostic utility, and are therapeutic targets. We built a regulatory map for 24 NRs, six chromatin state markers, and 14 breast-cancer-associated transcription factors (TFs that are expressed in the breast cancer cell line MCF-7. The resulting network reveals a highly interconnected regulatory matrix where extensive crosstalk occurs among NRs and other breast -cancer-associated TFs. We show that large numbers of factors are coordinately bound to highly occupied target regions throughout the genome, and these regions are associated with active chromatin state and hormone-responsive gene expression. This network also provides a framework for stratifying and predicting patient outcomes, and we use it to show that the peroxisome proliferator-activated receptor delta binds to a set of genes also regulated by the retinoic acid receptors and whose expression is associated with poor prognosis in breast cancer.

  6. The peroxisome proliferator-activated receptor: A family of nuclear receptors role in various diseases

    Directory of Open Access Journals (Sweden)

    Sandeep Tyagi

    2011-01-01

    Full Text Available Peroxisome proliferator-activated receptors (PPARs are ligand-activated transcription factors of nuclear hormone receptor superfamily comprising of the following three subtypes: PPARα, PPARγ, and PPARβ/δ. Activation of PPAR-α reduces triglyceride level and is involved in regulation of energy homeostasis. Activation of PPAR-γ causes insulin sensitization and enhances glucose metabolism, whereas activation of PPAR- β/δ enhances fatty acids metabolism. Thus, PPAR family of nuclear receptors plays a major regulatory role in energy homeostasis and metabolic function. The present review critically analyzes the protective and detrimental effect of PPAR agonists in dyslipidemia, diabetes, adipocyte differentiation, inflammation, cancer, lung diseases, neurodegenerative disorders, fertility or reproduction, pain, and obesity.

  7. Nuclear receptor TLX inhibits TGF-β signaling in glioblastoma.

    Science.gov (United States)

    Johansson, Erik; Zhai, Qiwei; Zeng, Zhao-Jun; Yoshida, Takeshi; Funa, Keiko

    2016-05-01

    TLX (also called NR2E1) is an orphan nuclear receptor that maintains stemness of neuronal stem cells. TLX is highly expressed in the most malignant form of glioma, glioblastoma multiforme (GBM), and is important for the proliferation and maintenance of the stem/progenitor cells of the tumor. Transforming Growth Factor-β (TGF-β) is a cytokine regulating many different cellular processes such as differentiation, migration, adhesion, cell death and proliferation. TGF-β has an important function in cancer where it can work as either a tumor suppressor or oncogene, depending on the cancer type and stage of tumor development. Since glioblastoma often have dysfunctional TGF-β signaling we wanted to find out if there is any interaction between TLX and TGF-β in glioblastoma cells. We demonstrate that knockdown of TLX enhances the canonical TGF-β signaling response in glioblastoma cell lines. TLX physically interacts with and stabilizes Smurf1, which can ubiquitinate and target TGF-β receptor II for degradation, whereas knockdown of TLX leads to stabilization of TGF-β receptor II, increased nuclear translocation of Smad2/3 and enhanced expression of TGF-β target genes. The interaction between TLX and TGF-β may play an important role in the regulation of proliferation and tumor-initiating properties of glioblastoma cells.

  8. Regulation of hepatic energy metabolism by the nuclear receptor PXR.

    Science.gov (United States)

    Hakkola, Jukka; Rysä, Jaana; Hukkanen, Janne

    2016-09-01

    The pregnane X receptor (PXR) is a nuclear receptor that is traditionally thought to be specialized for sensing xenobiotic exposure. In concurrence with this feature PXR was originally identified to regulate drug-metabolizing enzymes and transporters. During the last ten years it has become clear that PXR harbors broader functions. Evidence obtained both in experimental animals and humans indicate that ligand-activated PXR regulates hepatic glucose and lipid metabolism and affects whole body metabolic homeostasis. Currently, the consequences of PXR activation on overall metabolic health are not yet fully understood and varying results on the effect of PXR activation or knockout on metabolic disorders and weight gain have been published in mouse models. Rifampicin and St. John's wort, the prototypical human PXR agonists, impair glucose tolerance in healthy volunteers. Chronic exposure to PXR agonists could potentially represent a risk factor for diabetes and metabolic syndrome. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.

  9. DMPD: Nuclear receptors in macrophages: a link between metabolism and inflammation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18022390 Nuclear receptors in macrophages: a link between metabolism and inflammati...on. Szanto A, Roszer T. FEBS Lett. 2008 Jan 9;582(1):106-16. Epub 2007 Nov 20. (.png) (.svg) (.html) (.csml) Show Nuclear... receptors in macrophages: a link between metabolism and inflammation. PubmedID 18022390 Title Nuclear

  10. Gain-of-Function Alleles in Caenorhabditis elegans Nuclear Hormone Receptor nhr-49 Are Functionally Distinct

    Science.gov (United States)

    Lee, Kayoung; Goh, Grace Ying Shyen; Wong, Marcus Andrew; Klassen, Tara Leah

    2016-01-01

    Nuclear hormone receptors (NHRs) are transcription factors that regulate numerous physiological and developmental processes and represent important drug targets. NHR-49, an ortholog of Hepatocyte Nuclear Factor 4 (HNF4), has emerged as a key regulator of lipid metabolism and life span in the nematode worm Caenorhabditis elegans. However, many aspects of NHR-49 function remain poorly understood, including whether and how it regulates individual sets of target genes and whether its activity is modulated by a ligand. A recent study identified three gain-of-function (gof) missense mutations in nhr-49 (nhr-49(et7), nhr-49(et8), and nhr-49(et13), respectively). These substitutions all affect the ligand-binding domain (LBD), which is critical for ligand binding and protein interactions. Thus, these alleles provide an opportunity to test how three specific residues contribute to NHR-49 dependent gene regulation. We used computational and molecular methods to delineate how these mutations alter NHR-49 activity. We find that despite originating from a screen favoring the activation of specific NHR-49 targets, all three gof alleles cause broad upregulation of NHR-49 regulated genes. Interestingly, nhr-49(et7) and nhr-49(et8) exclusively affect nhr-49 dependent activation, whereas the nhr-49(et13) surprisingly affects both nhr-49 mediated activation and repression, implicating the affected residue as dually important. We also observed phenotypic non-equivalence of these alleles, as they unexpectedly caused a long, short, and normal life span, respectively. Mechanistically, the gof substitutions altered neither protein interactions with the repressive partner NHR-66 and the coactivator MDT-15 nor the subcellular localization or expression of NHR-49. However, in silico structural modeling revealed that NHR-49 likely interacts with small molecule ligands and that the missense mutations might alter ligand binding, providing a possible explanation for increased NHR-49 activity. In

  11. Bile acid nuclear receptor FXR and digestive system diseases

    Directory of Open Access Journals (Sweden)

    Lili Ding

    2015-03-01

    Full Text Available Bile acids (BAs are not only digestive surfactants but also important cell signaling molecules, which stimulate several signaling pathways to regulate some important biological processes. The bile-acid-activated nuclear receptor, farnesoid X receptor (FXR, plays a pivotal role in regulating bile acid, lipid and glucose homeostasis as well as in regulating the inflammatory responses, barrier function and prevention of bacterial translocation in the intestinal tract. As expected, FXR is involved in the pathophysiology of a wide range of diseases of gastrointestinal tract, including inflammatory bowel disease, colorectal cancer and type 2 diabetes. In this review, we discuss current knowledge of the roles of FXR in physiology of the digestive system and the related diseases. Better understanding of the roles of FXR in digestive system will accelerate the development of FXR ligands/modulators for the treatment of digestive system diseases.

  12. Mycotoxins and Nuclear Receptors: A Still Underexplored Issue

    Directory of Open Access Journals (Sweden)

    C. Dall'Asta

    2016-12-01

    Full Text Available Mycotoxins are fungal secondary metabolites that can be found in food commodities worldwide. They exert a wide range of adverse effects towards humans and animals. Although toxicological studies have addressed these food contaminants over decades, their mode of actions as well as their synergistic effects are still to be deeply clarified. Among the toxicological targets, nuclear receptors have been identified by several studies. Besides the estrogenic effect, a wider range of endocrine and neuroendocrine disrupting effects have been reported so far. This review is aimed at addressing the recent advances in toxicology, and at highlighting possible gaps of knowledge.

  13. 过氧化物酶体增殖物激活受体γ辅助活化因子-1α在脑缺血中的神经保护作用%Neuroprotective effect of peroxisome proliferator-activated receptor γ coactivator-1α in cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    韩勇; 沙杜鹃; 张均

    2012-01-01

    Peroxisome proliferative-activated receptor (PPAR) γ coactivator-1α (PGC-1α) is a transcriptional coactivator of PPARγ.PGC-1α can bind with many different transcription factors.It plays a number of functions in the different tissues and the process of biological reaction.Recent studies have shown that PGC-1α signaling pathway has a neuroprotective effect.This article reviews the neuroprotective effect of PGC-1α in cerebral ischernia and its possible mechanisms.%过氧化物酶体增殖激活受体(peroxisome proliferator-activated receptor,PPAR)γ辅助活化因子-1α(PPARγ coactivator-1α,PGC-1α)是PPARγ的转录辅助活化因子.PGC-1α能与许多不同转录因子结合,在不同组织和生物反应过程中发挥众多功能.最近的研究显示,PGC-1α信号转导通路具有神经保护作用.文章就PGC-1α在脑缺血中的神经保护作用及其可能机制进行了综述.

  14. Effect of Antisense Mediated BCL-2 Suppression on the Expression of the Androgen Receptor and Coactivating p300 and CREB Binding Proteins

    Directory of Open Access Journals (Sweden)

    Marvin Rubenstein

    2013-12-01

    Full Text Available Antisense oligonucleotides (oligos have been employed against in vivo and in vitro prostate cancer models. While most oligos target growth factors or their receptors, others are directed against inhibitors of apoptosis or mediators of androgen activity. In previous experiments, mono- and bispecific oligos directed against bcl-2 suppressed both the targeted bcl-2 protein (an inhibitor of apoptosis and non-targeted caspase-3 (a promoter of apoptosis, potentially negating the effect of therapeutic bcl-2 inhibition. Subsequently we reported that AR and p300 expression were significantly enhanced by these oligos. In a continuation of this study, we now report that the expression of another androgen receptor co-stimulatory protein, CREB binding protein (CREBBP, is not similarly increased. These data suggest that oligo treatment directed against bcl-2 can be evaded through compensatory increases in AR and p300 expression. Increased AR and p300 expression may transition the tumor to a more dedifferentiated and aggressive phenotype. However, not all co-stimulating proteins (CREBBP are involved, and this may be important when controlling unanticipated (compensatory effects of gene therapy.

  15. A Pleiotropic Role for the Orphan Nuclear Receptor Small Heterodimer Partner in Lipid Homeostasis and Metabolic Pathways

    Directory of Open Access Journals (Sweden)

    Gabriella Garruti

    2012-01-01

    Full Text Available Nuclear receptors (NRs comprise one of the most abundant classes of transcriptional regulators of metabolic diseases and have emerged as promising pharmaceutical targets. Small heterodimer partner (SHP; NR0B2 is a unique orphan NR lacking a DNA-binding domain but contains a putative ligand-binding domain. SHP is a transcriptional regulator affecting multiple key biological functions and metabolic processes including cholesterol, bile acid, and fatty acid metabolism, as well as reproductive biology and glucose-energy homeostasis. About half of all mammalian NRs and several transcriptional coregulators can interact with SHP. The SHP-mediated repression of target transcription factors includes at least three mechanisms including direct interference with the C-terminal activation function 2 (AF2 coactivator domains of NRs, recruitment of corepressors, or direct interaction with the surface of NR/transcription factors. Future research must focus on synthetic ligands acting on SHP as a potential therapeutic target in a series of metabolic abnormalities. Current understanding about the pleiotropic role of SHP is examined in this paper, and principal metabolic aspects connected with SHP function will be also discussed.

  16. Regulation of adipogenesis by nuclear receptor PPARγ is modulated by the histone demethylase JMJD2C

    National Research Council Canada - National Science Library

    Lizcano, Fernando; Romero, Carolina; Vargas, Diana

    2011-01-01

    .... The nuclear receptor Peroxisome Proliferator-activated receptor gamma (PPARγ) is the master regulator of adipose cell differentiation and its functional activation is currently used as a therapeutic approach for Diabetes Mellitus type 2...

  17. High-fat diet-induced reduction of peroxisome proliferator-activated receptorcoactivator-1α messenger RNA levels and oxidative capacity in the soleus muscle of rats with metabolic syndrome.

    Science.gov (United States)

    Nagatomo, Fumiko; Fujino, Hidemi; Kondo, Hiroyo; Takeda, Isao; Tsuda, Kinsuke; Ishihara, Akihiko

    2012-02-01

    Animal models of type 2 diabetes exhibit reduced peroxisome proliferator-activated receptorcoactivator-1α (PGC-1α) messenger RNA (mRNA) levels, which are associated with decreased oxidative capacity, in skeletal muscles. In contrast, animal models with metabolic syndrome show normal PGC-1α mRNA levels. We hypothesized that a high-fat diet decreases PGC-1α mRNA levels in skeletal muscles of rats with metabolic syndrome, reducing muscle oxidative capacity and accelerating metabolic syndrome or inducing type 2 diabetes. We examined mRNA levels and fiber profiles in the soleus muscles of rats with metabolic syndrome (SHR/NDmcr-cp [cp/cp]; CP) fed a high-fat diet. Five-week-old CP rats were assigned to a sedentary group (CP-N) that was fed a standard diet (15.1 kJ/g, 23.6% protein, 5.3% fat, and 54.4% carbohydrates) or a sedentary group (CP-H) that was fed a high-fat diet (21.6 kJ/g, 23.6% protein, 34.9% fat, and 25.9% carbohydrates) and were housed for 10 weeks. Body weight, energy intake, and systolic blood pressure were higher in the CP-H group than in the CP-N group. Nonfasting glucose, triglyceride, total cholesterol, and leptin levels were higher in the CP-H group than in the CP-N group. There was no difference in insulin levels between the CP-N and CP-H groups. Muscle PGC-1α mRNA levels and succinate dehydrogenase activity were lower in the CP-H group than in the CP-N group. We concluded that a high-fat diet reduces PGC-1α mRNA levels and oxidative capacity in skeletal muscles and accelerates metabolic syndrome.

  18. Role of nuclear receptors in breast cancer stem cells

    Institute of Scientific and Technical Information of China (English)

    Alessio; Papi; Marina; Orlandi

    2016-01-01

    The recapitulation of primary tumour heterogenity and the existence of a minor sub-population of cancer cells,capable of initiating tumour growth in xenografts on serial passages, led to the hypothesis that cancer stem cells(CSCs) exist. CSCs are present in many tumours, among which is breast cancer. Breast CSCs(BCSCs) are likely to sustain the growth of the primary tumour mass, as wellas to be responsible for disease relapse and metastatic spreading. Consequently, BCSCs represent the most significant target for new drugs in breast cancer therapy. Both the hypoxic condition in BCSCs biology and proinflammatory cytokine network has gained increasing importance in the recent past. Breast stromal cells are crucial components of the tumours milieu and are a major source of inflammatory mediators. Recently, the antiinflammatory role of some nuclear receptors ligands has emerged in several diseases, including breast cancer. Therefore, the use of nuclear receptors ligands may be a valid strategy to inhibit BCSCs viability and consequently breast cancer growth and disease relapse.

  19. Nuclear Receptor Regulation of Aquaporin-2 in the Kidney

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Zhang

    2016-07-01

    Full Text Available Aquaporin-2 (AQP2 is a vasopressin-regulated water channel responsible for regulating water reabsorption through the apical plasma membrane of the principal cells of renal collecting ducts. It has been found that dysregulation and dysfunction of AQP2 cause many disorders related to water balance in people and animals, including polyuria and dilutional hyponatremia. Classically, AQP2 mRNA and protein expression and its membrane translocation are regulated by systemic vasopressin involving short-term regulation of AQP2 trafficking to and from the apical plasma membrane and long-term regulation of the total amount of the AQP2 protein in the cell. Recently, increasing evidence has demonstrated that collecting duct AQP2 expression and membrane translocation are also under the control of many other local factors, especially nuclear receptors. Here, we briefly review the progress of studies in this area and discuss the role of nuclear receptors in the regulation of water reabsorption via affecting AQP2 expression and function.

  20. Atypical nuclear localization of VIP receptors in glioma cell lines and patients.

    Science.gov (United States)

    Barbarin, Alice; Séité, Paule; Godet, Julie; Bensalma, Souheyla; Muller, Jean-Marc; Chadéneau, Corinne

    2014-11-28

    An increasing number of G protein-coupled receptors, like receptors for vasoactive intestinal peptide (VIP), are found in cell nucleus. As VIP receptors are involved in the regulation of glioma cell proliferation and migration, we investigated the expression and the nuclear localization of the VIP receptors VPAC1 and VPAC2 in this cancer. First, by applying Western blot and immunofluorescence detection in three human glioblastoma (GBM) cell lines, we observed a strong nuclear staining for the VPAC1 receptor and a weak nuclear VPAC2 receptor staining. Second, immunohistochemical staining of VPAC1 and VPAC2 on tissue microarrays (TMA) showed that the two receptors were expressed in normal brain and glioma tissues. Expression in the non-nuclear compartment of the two receptors significantly increased with the grade of the tumors. Analysis of nuclear staining revealed a significant increase of VPAC1 staining with glioma grade, with up to 50% of GBM displaying strong VPAC1 nuclear staining, whereas nuclear VPAC2 staining remained marginal. The increase in VPAC receptor expression with glioma grades and the enhanced nuclear localization of the VPAC1 receptors in GBM might be of importance for glioma progression.

  1. The transcriptional coactivator PGC-1alpha mediates exercise-induced angiogenesis in skeletal muscle.

    Science.gov (United States)

    Chinsomboon, Jessica; Ruas, Jorge; Gupta, Rana K; Thom, Robyn; Shoag, Jonathan; Rowe, Glenn C; Sawada, Naoki; Raghuram, Srilatha; Arany, Zoltan

    2009-12-15

    Peripheral arterial disease (PAD) affects 5 million people in the US and is the primary cause of limb amputations. Exercise remains the single best intervention for PAD, in part thought to be mediated by increases in capillary density. How exercise triggers angiogenesis is not known. PPARgamma coactivator (PGC)-1alpha is a potent transcriptional co-activator that regulates oxidative metabolism in a variety of tissues. We show here that PGC-1alpha mediates exercise-induced angiogenesis. Voluntary exercise induced robust angiogenesis in mouse skeletal muscle. Mice lacking PGC-1alpha in skeletal muscle failed to increase capillary density in response to exercise. Exercise strongly induced expression of PGC-1alpha from an alternate promoter. The induction of PGC-1alpha depended on beta-adrenergic signaling. beta-adrenergic stimulation also induced a broad program of angiogenic factors, including vascular endothelial growth factor (VEGF). This induction required PGC-1alpha. The orphan nuclear receptor ERRalpha mediated the induction of VEGF by PGC-1alpha, and mice lacking ERRalpha also failed to increase vascular density after exercise. These data demonstrate that beta-adrenergic stimulation of a PGC-1alpha/ERRalpha/VEGF axis mediates exercise-induced angiogenesis in skeletal muscle.

  2. Analysis of the heat shock response in mouse liver reveals transcriptional dependence on the nuclear receptor peroxisome proliferator-activated receptor α (PPARα

    Directory of Open Access Journals (Sweden)

    Jonnalagadda Sudhakar

    2010-01-01

    Full Text Available Abstract Background The nuclear receptor peroxisome proliferator-activated receptor alpha (PPARα regulates responses to chemical or physical stress in part by altering expression of genes involved in proteome maintenance. Many of these genes are also transcriptionally regulated by heat shock (HS through activation by HS factor-1 (HSF1. We hypothesized that there are interactions on a genetic level between PPARα and the HS response mediated by HSF1. Results Wild-type and PPARα-null mice were exposed to HS, the PPARα agonist WY-14,643 (WY, or both; gene and protein expression was examined in the livers of the mice 4 or 24 hrs after HS. Gene expression profiling identified a number of Hsp family members that were altered similarly in both mouse strains. However, most of the targets of HS did not overlap between strains. A subset of genes was shown by microarray and RT-PCR to be regulated by HS in a PPARα-dependent manner. HS also down-regulated a large set of mitochondrial genes specifically in PPARα-null mice that are known targets of PPARγ co-activator-1 (PGC-1 family members. Pretreatment of PPARα-null mice with WY increased expression of PGC-1β and target genes and prevented the down-regulation of the mitochondrial genes by HS. A comparison of HS genes regulated in our dataset with those identified in wild-type and HSF1-null mouse embryonic fibroblasts indicated that although many HS genes are regulated independently of both PPARα and HSF1, a number require both factors for HS responsiveness. Conclusions These findings demonstrate that the PPARα genotype has a dramatic effect on the transcriptional targets of HS and support an expanded role for PPARα in the regulation of proteome maintenance genes after exposure to diverse forms of environmental stress including HS.

  3. Nanostructured sensors containing immobilized nuclear receptors for thyroid hormone detection.

    Science.gov (United States)

    Bendo, Luana; Casanova, Monise; Figueira, Ana Carolina M; Polikarpov, Igor; Zucolotto, Valtencir

    2014-05-01

    Thyroid hormone receptors (TRs) are members of the nuclear receptors (NRs) superfamily, being encoded by two genes: TRa and TRbeta. In this paper, the ligand-binding domain (LBD) of the TRbeta1 isoform was immobilized on the surface of nanostructured electrodes for TR detection. The platforms containing TRbeta1-LBD were applied to the detection of specific ligand agonists, including the natural hormones T3 (triiodothyronine) and T4 (thyroxine), and the synthetic agonists TRIAC (3,5,3'-triiodothyroacetic acid) and GC-1 [3,5-dimethyl-4-(4'-hydroxy-3'-isopropylbenzyl phenoxy) acetic acid]. Detection was performed via impedance spectroscopy. The biosensors were capable of distinguishing between the thyroid hormones T3 and T4, and/or the analogues TRIAC and GC-1 at concentrations as low as 50 nM. The detection and separation of thyroid hormones and analogue ligands by impedance techniques represents an innovative tool in the field of nanomedicine because it allows the design of inexpensive devices for the rapid and real-time detection of distinct ligand/receptor systems.

  4. CRTC2 Is a Coactivator of GR and Couples GR and CREB in the Regulation of Hepatic Gluconeogenesis.

    Science.gov (United States)

    Hill, Micah J; Suzuki, Shigeru; Segars, James H; Kino, Tomoshige

    2016-01-01

    Glucocorticoid hormones play essential roles in the regulation of gluconeogenesis in the liver, an adaptive response that is required for the maintenance of circulating glucose levels during fasting. Glucocorticoids do this by cooperating with glucagon, which is secreted from pancreatic islets to activate the cAMP-signaling pathway in hepatocytes. The cAMP-response element-binding protein (CREB)-regulated transcription coactivator 2 (CRTC2) is a coactivator known to be specific to CREB and plays a central role in the glucagon-mediated activation of gluconeogenesis in the early phase of fasting. We show here that CRTC2 also functions as a coactivator for the glucocorticoid receptor (GR). CRTC2 strongly enhances GR-induced transcriptional activity of glucocorticoid-responsive genes. CRTC2 physically interacts with the ligand-binding domain of the GR through a region spanning amino acids 561-693. Further, CRTC2 is required for the glucocorticoid-associated cooperative mRNA expression of the glucose-6-phosphatase, a rate-limiting enzyme for hepatic gluconeogenesis, by facilitating the attraction of GR and itself to its promoter region already occupied by CREB. CRTC2 is required for the maintenance of blood glucose levels during fasting in mice by enhancing the GR transcriptional activity on both the G6p and phosphoenolpyruvate carboxykinase (Pepck) genes. Finally, CRTC2 modulates the transcriptional activity of the progesterone receptor, indicating that it may influence the transcriptional activity of other steroid/nuclear receptors. Taken together, these results reveal that CRTC2 plays an essential role in the regulation of hepatic gluconeogenesis through coordinated regulation of the glucocorticoid/GR- and glucagon/CREB-signaling pathways on the key genes G6P and PEPCK.

  5. Controlling Androgen receptor nuclear localization by dendrimer conjugates

    Science.gov (United States)

    Wang, Haoyu

    Androgen Receptor (AR) antagonists, such as bicalutamide and flutamide have been used widely in the treatment of prostate cancer. Although initial treatment is effective, prostate cancer cells often acquire antiandrogen resistance with prolonged treatment. AR over-expression and AR mutations contribute to the development of antiandrogen resistant cancer. Second generation antiandrogens such as enzalutamide are more effective and show reduced AR nuclear localization. In this study, derivatives of PAN52, a small molecule antiandrogen previously developed in our lab, were conjugated to the surface of generation 4 and generation 6 PAMAM dendrimers to obtain antiandrogen PAMAM dendrimer conjugates (APDC). APDCs readily enter cells and associate with AR in the cytoplasm. Due to their large size and positive charge, they can not enter the nucleus, thus retaining AR in the cytoplasm. In addition, APDCs are effective in decreasing AR mediated transcription and cell proliferation. APDC is the first AR antagonists that inhibit DHT-induced nuclear localization of AR. By inhibiting AR nuclear localization, APDC represents a new class of antiandrogens that offer an alternative approach to addressing antiandrogen-resistant prostate cancer. Lysine post-translational modification of AR Nuclear Localization Sequence (NLS) has great impact on AR cellular localization. It is of interest to understand which modifications modulate AR translocation into the nucleus. In this study, we prepared dendrimer-based acetyltransferase mimetic (DATM), DATM is able to catalytically acetylate AR in CWR22Rv1 cells, which will be a useful tool for studying AR modification effect on AR cellular localization. Derivatives of DATM, which transfer other chemical groups to AR, can be prepared similarly, and with more dendrimer based AR modification tools prepared in future, we will be able to understand and control AR cellular localization through AR modification.

  6. Nuclear receptor atlas of female mouse liver parenchymal, endothelial, and Kupffer cells.

    Science.gov (United States)

    Li, Zhaosha; Kruijt, J Kar; van der Sluis, Ronald J; Van Berkel, Theo J C; Hoekstra, Menno

    2013-04-01

    The liver consists of different cell types that together synchronize crucial roles in liver homeostasis. Since nuclear receptors constitute an important class of drug targets that are involved in a wide variety of physiological processes, we have composed the hepatic cell type-specific expression profile of nuclear receptors to uncover the pharmacological potential of liver-enriched nuclear receptors. Parenchymal liver cells (hepatocytes) and liver endothelial and Kupffer cells were isolated from virgin female C57BL/6 wild-type mice using collagenase perfusion and counterflow centrifugal elutriation. The hepatic expression pattern of 49 nuclear receptors was generated by real-time quantitative PCR using the NUclear Receptor Signaling Atlas (NURSA) program resources. Thirty-six nuclear receptors were expressed in total liver. FXR-α, EAR2, LXR-α, HNF4-α, and CAR were the most abundantly expressed nuclear receptors in liver parenchymal cells. In contrast, NUR77, COUP-TFII, LXR-α/β, FXR-α, and EAR2 were the most highly expressed nuclear receptors in endothelial and Kupffer cells. Interestingly, members of orphan receptor COUP-TF family showed a distinct expression pattern. EAR2 was highly and exclusively expressed in parenchymal cells, while COUP-TFII was moderately and exclusively expressed in endothelial and Kupffer cells. Of interest, the orphan receptor TR4 showed a similar expression pattern as the established lipid sensor PPAR-γ. In conclusion, our study provides the most complete quantitative assessment of the nuclear receptor distribution in liver reported to date. Our gene expression catalog suggests that orphan nuclear receptors such as COUP-TFII, EAR2, and TR4 may be of significant importance as novel targets for pharmaceutical interventions in liver.

  7. Dual activities of odorants on olfactory and nuclear hormone receptors.

    Science.gov (United States)

    Pick, Horst; Etter, Sylvain; Baud, Olivia; Schmauder, Ralf; Bordoli, Lorenza; Schwede, Torsten; Vogel, Horst

    2009-10-30

    We have screened an odorant compound library and discovered molecules acting as chemical signals that specifically activate both G-protein-coupled olfactory receptors (ORs) on the cell surface of olfactory sensory neurons and the human nuclear estrogen receptor alpha (ER) involved in transcriptional regulation of cellular differentiation and proliferation in a wide variety of tissues. Hence, these apparent dual active odorants induce distinct signal transduction pathways at different subcellular localizations, which affect both neuronal signaling, resulting in odor perception, and the ER-dependent transcriptional control of specific genes. We demonstrate these effects using fluorescence-based in vitro and cellular assays. Among these odorants, we have identified synthetic sandalwood compounds, an important class of molecules used in the fragrance industry. For one estrogenic odorant we have also identified the cognate OR. This prompted us to compare basic molecular recognition principles of odorants on the two structurally and apparent functionally non-related receptors using computational modeling in combination with functional assays. Faced with the increasing evidence that ORs may perform chemosensory functions in a number of tissues outside of the nasal olfactory epithelium, the unraveling of these molecular ligand-receptor interaction principles is of critical importance. In addition the evidence that certain olfactory sensory neurons naturally co-express ORs and ERs may provide a direct functional link between the olfactory and hormonal systems in humans. Our results are therefore useful for defining the structural and functional characteristics of ER-specific odorants and the role of odorant molecules in cellular processes other than olfaction.

  8. Nuclear Receptor 4A1 (NR4A1 as a Drug Target for Renal Cell Adenocarcinoma.

    Directory of Open Access Journals (Sweden)

    Erik Hedrick

    Full Text Available The orphan nuclear receptor NR4A1 exhibits pro-oncogenic activity in cancer cell lines. NR4A1 activates mTOR signaling, regulates genes such as thioredoxin domain containing 5 and isocitrate dehydrogenase 1 that maintain low oxidative stress, and coactivates specificity protein 1 (Sp1-regulated pro-survival and growth promoting genes. Transfection of renal cell carcinoma (RCC ACHN and 786-O cells with oligonucleotides that target NR4A1 results in a 40-60% decrease in cell proliferation and induction of apoptosis. Moreover, knockdown of NR4A1 in RCC cells decreased bcl-2, survivin and epidermal growth factor receptor expression, inhibited of mTOR signaling, induced oxidative and endoplasmic reticulum stress, and decreased TXNDC5 and IDH1. We have recently demonstrated that selected 1,1-bis(3'-indolyl-1-(p-substituted phenylmethane (C-DIM compounds including the p-hydroxyphenyl (DIM-C-pPhOH and p-carboxymethyl (DIM-C-pPhCO2Me analogs bind NR4A1 and act as antagonists. Both DIM-C-pPhOH and DIM-C-pPhCO2Me inhibited growth and induced apoptosis in ACHN and 786-O cells, and the functional and genomic effects of the NR4A1 antagonists were comparable to those observed after NR4A1 knockdown. These results indicate that NR4A1 antagonists target multiple growth promoting and pro-survival pathways in RCC cells and in tumors (xenograft and represent a novel chemotherapy for treating RCC.

  9. Receptors and ionic transporters in nuclear membranes: new targets for therapeutical pharmacological interventions.

    Science.gov (United States)

    Bkaily, Ghassan; Avedanian, Levon; Al-Khoury, Johny; Ahmarani, Lena; Perreault, Claudine; Jacques, Danielle

    2012-08-01

    Work from our group and other laboratories showed that the nucleus could be considered as a cell within a cell. This is based on growing evidence of the presence and role of nuclear membrane G-protein coupled receptors and ionic transporters in the nuclear membranes of many cell types, including vascular endothelial cells, endocardial endothelial cells, vascular smooth muscle cells, cardiomyocytes, and hepatocytes. The nuclear membrane receptors were found to modulate the functioning of ionic transporters at the nuclear level, and thus contribute to regulation of nuclear ionic homeostasis. Nuclear membranes of the mentioned types of cells possess the same ionic transporters; however, the type of receptors is cell-type dependent. Regulation of cytosolic and nuclear ionic homeostasis was found to be dependent upon a tight crosstalk between receptors and ionic transporters of the plasma membranes and those of the nuclear membrane. This crosstalk seems to be the basis for excitation-contraction coupling, excitation-secretion coupling, and excitation - gene expression coupling. Further advancement in this field will certainly shed light on the role of nuclear membrane receptors and transporters in health and disease. This will in turn enable the successful design of a new class of drugs that specifically target such highly vital nuclear receptors and ionic transporters.

  10. Phenobarbital and Insulin Reciprocate Activation of the Nuclear Receptor Constitutive Androstane Receptor through the Insulin Receptor.

    Science.gov (United States)

    Yasujima, Tomoya; Saito, Kosuke; Moore, Rick; Negishi, Masahiko

    2016-05-01

    Phenobarbital (PB) antagonized insulin to inactivate the insulin receptor and attenuated the insulin receptor downstream protein kinase B (AKT)-forkhead box protein O1 and extracellular signal-regulated kinase 1/2 signals in mouse primary hepatocytes and HepG2 cells. Hepatic AKT began dephosphorylation in an early stage of PB treatment, and blood glucose levels transiently increased in both wild-type and constitutive androstane receptor (CAR) knockout (KO) mice. On the other hand, blood glucose levels increased in wild-type mice, but not KO mice, in later stages of PB treatment. As a result, PB, acting as an insulin receptor antagonist, elicited CAR-independent increases and CAR-dependent decreases of blood glucose levels at these different stages of treatment, respectively. Reciprocally, insulin activation of the insulin receptor repressed CAR activation and induction of its target CYP2B6 gene in HepG2 cells. Thus, PB and insulin cross-talk through the insulin receptor to regulate glucose and drug metabolism reciprocally.

  11. Loss of the nuclear receptor corepressor SLIRP compromises male fertility.

    Directory of Open Access Journals (Sweden)

    Shane M Colley

    Full Text Available Nuclear receptors (NRs and their coregulators play fundamental roles in initiating and directing gene expression influencing mammalian reproduction, development and metabolism. SRA stem Loop Interacting RNA-binding Protein (SLIRP is a Steroid receptor RNA Activator (SRA RNA-binding protein that is a potent repressor of NR activity. SLIRP is present in complexes associated with NR target genes in the nucleus; however, it is also abundant in mitochondria where it affects mitochondrial mRNA transcription and energy turnover. In further characterisation studies, we observed SLIRP protein in the testis where its localization pattern changes from mitochondrial in diploid cells to peri-acrosomal and the tail in mature sperm. To investigate the in vivo effects of SLIRP, we generated a SLIRP knockout (KO mouse. This animal is viable, but sub-fertile. Specifically, when homozygous KO males are crossed with wild type (WT females the resultant average litter size is reduced by approximately one third compared with those produced by WT males and females. Further, SLIRP KO mice produced significantly fewer progressively motile sperm than WT animals. Electron microscopy identified disruption of the mid-piece/annulus junction in homozygous KO sperm and altered mitochondrial morphology. In sum, our data implicates SLIRP in regulating male fertility, wherein its loss results in asthenozoospermia associated with compromised sperm structure and mitochondrial morphology.

  12. Nuclear receptors in inflammation control: repression by GR and beyond.

    Science.gov (United States)

    Chinenov, Yurii; Gupte, Rebecca; Rogatsky, Inez

    2013-11-05

    Inflammation is a protective response of organisms to pathogens, irritation or injury. Primary inflammatory sensors activate an array of signaling pathways that ultimately converge upon a few transcription factors such as AP1, NFκB and STATs that in turn stimulate expression of inflammatory genes to ultimately eradicate infection and repair the damage. A disturbed balance between activation and inhibition of inflammatory pathways can set the stage for chronic inflammation which is increasingly recognized as a key pathogenic component of autoimmune, metabolic, cardiovascular and neurodegenerative disorders. Nuclear receptors (NRs) are a large family of transcription factors many of which are known for their potent anti-inflammatory actions. Activated by small lipophilic ligands, NRs interact with a wide range of transcription factors, cofactors and chromatin-modifying enzymes, assembling numerous cell- and tissue-specific DNA-protein transcriptional regulatory complexes with diverse activities. Here we discuss established and emerging roles and mechanisms by which NRs and, in particular, the glucocorticoid receptor (GR) repress genes encoding cytokines, chemokines and other pro-inflammatory mediators.

  13. Multiple Novel Signals Mediate Thyroid Hormone Receptor Nuclear Import and Export*

    OpenAIRE

    Mavinakere, Manohara S.; Powers, Jeremy M.; Subramanian, Kelly S.; Roggero, Vincent R.; Allison, Lizabeth A.

    2012-01-01

    Thyroid hormone receptor (TR) is a member of the nuclear receptor superfamily that shuttles between the cytosol and nucleus. The fine balance between nuclear import and export of TR has emerged as a critical control point for modulating thyroid hormone-responsive gene expression; however, sequence motifs of TR that mediate shuttling are not fully defined. Here, we characterized multiple signals that direct TR shuttling. Along with the known nuclear localization signal in the hinge domain, we ...

  14. Characterization of nuclear localization signals and cytoplasmic retention region in the nuclear receptor CAR.

    Science.gov (United States)

    Kanno, Yuichiro; Suzuki, Motoyoshi; Nakahama, Takayuki; Inouye, Yoshio

    2005-09-10

    The constitutive androstane receptor (CAR) is a ligand/activator-dependent transactivation factor that resides in the cytoplasm and forms part of an as yet unidentified protein complex. Upon stimulation, CAR translocates into the nucleus where it modulates the transactivation of target genes. However, CAR exogenously expressed in rat liver RL-34 cells is located in the nucleus even in the absence of activators. By transiently transfecting RL-34 cells with various mutated rat CAR segments, we identified two nuclear localization signals: a basic amino acid-rich sequence (RRARQARRR) between amino acids 100 and 108; and an assembly of noncontiguous residues widely spread over amino acid residues 111 to 320 within the ligand binding domain. A C-terminal leucine-rich segment corresponding to a previously reported murine xenochemical response signal was not found to exhibit nuclear import activity in cultured cells. Using rat primary hepatocytes transfected with various CAR segments, we identified the region required for the cytoplasmic retention of CAR. Based on these results, the intracellular localization of CAR would be determined by the combined effects of nuclear localization signals, the xenochemical response signal, and the cytoplasmic retention region.

  15. Association between peroxisome proliferator-activated receptor-γcoactivator-1α gene polymorphisms and type 2 diabetes in southern Chinese population: role of altered interaction with myocyte enhancer factor 2C

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-ling; LU Wen-sheng; YAN Li; WU Mu-chao; XU Ming-tong; CHEN Li-hong; CHENG Hua

    2007-01-01

    Background Some single nucleotide polymorphisms (SNPs) in the peroxisome proliferator-activated receptor-Y coactivator (PGC)-1α gene have been reported to be associated with type 2 diabetes in different populations, and studies on Chinese patients yielded controversial results. The objective of this case-control study was to explore the relationship between SNPs of PGC-1a and type 2 diabetes in the southern Chinese population and to determine whether the common variants: Gly482Ser and Thr394Thr, in the PGC-1α gene have any impacts on interaction with myocyte enhancer factor (MEF) 2C.Methods The SNPs in all exons of the PGC-1α gene was investigated in 50 type 2 diabetic patients using polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and direct sequencing. Thereafter, 263 type 2diabetic patients and 282 healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). A bacterial two-hybrid system and site-directed mutagenesis were used to investigate whether Gly482Ser and Thr394Thr variants in the PGC-1α gene alter the interaction with MEF2C.Results Three frequent SNPs (Thr394Thr, Gly482Ser and Thr528Thr) were found in exons of the PGC-1α gene. Only the Gly482Ser variant had a different distribution between diabetic patients and healthy subjects, with the 482Ser allele more frequent in patients than in controls (40.1% vs 29.3%, P<0.01). Even in controls, the 482Ser(A) carriers were more likely to have higher levels of total cholesterol and low-density lipoprotein cholesterol than the 482Gly(G) carriers. The 394A-482G-528A haplotype was associated with protection from diabetes, while the 394A-482A-528A was associated with the susceptibility to diabetes. The bacterial two-hybrid system and site-directed mutagenesis revealed that the 482Ser variant was less efficient than the 482Gly variant to interact with MEF2C, whereas the 394Thr (A) had a synergic effect on the interaction between

  16. Nicotinamide riboside restores cognition through an upregulation of proliferator-activated receptorcoactivator 1α regulated β-secretase 1 degradation and mitochondrial gene expression in Alzheimer's mouse models.

    Science.gov (United States)

    Gong, Bing; Pan, Yong; Vempati, Prashant; Zhao, Wei; Knable, Lindsay; Ho, Lap; Wang, Jun; Sastre, Magdalena; Ono, Kenjiro; Sauve, Anthony A; Pasinetti, Giulio M

    2013-06-01

    Nicotinamide adenine dinucleotide (NAD)(+), a coenzyme involved in redox activities in the mitochondrial electron transport chain, has been identified as a key regulator of the lifespan-extending effects, and the activation of NAD(+) expression has been linked with a decrease in beta-amyloid (Aβ) toxicity in Alzheimer's disease (AD). Nicotinamide riboside (NR) is a NAD(+) precursor, it promotes peroxisome proliferator-activated receptorcoactivator 1 (PGC)-1α expression in the brain. Evidence has shown that PGC-1α is a crucial regulator of Aβ generation because it affects β-secretase (BACE1) degradation. In this study we tested the hypothesis that NR treatment in an AD mouse model could attenuate Aβ toxicity through the activation of PGC-1α-mediated BACE1 degradation. Using the Tg2576 AD mouse model, using in vivo behavioral analyses, biochemistry assays, small hairpin RNA (shRNA) gene silencing and electrophysiological recording, we found (1) dietary treatment of Tg2576 mice with 250 mg/kg/day of NR for 3 months significantly attenuates cognitive deterioration in Tg2576 mice and coincides with an increase in the steady-state levels of NAD(+) in the cerebral cortex; (2) application of NR to hippocampal slices (10 μM) for 4 hours abolishes the deficits in long-term potentiation recorded in the CA1 region of Tg2576 mice; (3) NR treatment promotes PGC-1α expression in the brain coinciding with enhanced degradation of BACE1 and the reduction of Aβ production in Tg2576 mice. Further in vitro studies confirmed that BACE1 protein content is decreased by NR treatment in primary neuronal cultures derived from Tg2576 embryos, in which BACE1 degradation was prevented by PGC-1α-shRNA gene silencing; and (4) NR treatment and PGC-1α overexpression enhance BACE1 ubiquitination and proteasomal degradation. Our studies suggest that dietary treatment with NR might benefit AD cognitive function and synaptic plasticity, in part by promoting PGC-1α-mediated BACE1

  17. Mode of Action and Human Relevance Analysis for Nuclear Receptor-Mediated Liver Toxicity: A Case Study with Phenobarbital as a Model Constitutive Androstane Receptor (CAR) Activator

    Science.gov (United States)

    The constitutive androstane receptor (CAR) and pregnane X receptor (PXR) are key nuclear receptors involved in the regulation of cellular responses. to exposure to many xenobiotics and various physiological processes. Phenobarbital (PB) is a non­ genotoxic i...

  18. A Structural Investigation into Oct4 Regulation by Orphan Nuclear Receptors, Germ Cell Nuclear Factor (GCNF) and Liver Receptor Homolog-1 (LRH-1).

    Science.gov (United States)

    Weikum, Emily R; Tuntland, Micheal L; Murphy, Michael N; Ortlund, Eric A

    2016-10-27

    Oct4 is a transcription factor required for maintaining pluripotency and self-renewal in stem cells. Prior to differentiation, Oct4 must be silenced to allow for the development of the three germ layers in the developing embryo. This fine-tuning is controlled by the nuclear receptors, liver receptor homolog-1 and germ cell nuclear factor. Liver receptor homolog-1 is responsible for driving the expression of Oct4 where germ cell nuclear factor represses its expression upon differentiation. Both receptors bind to a DR0 motif located within the Oct4 promoter. Here, we present the first structure of mouse germ cell nuclear factor DNA binding domain in complex with the Oct4 DR0. The overall structure revealed two molecules bound in a head-to-tail fashion on opposite sides of the DNA. Additionally, we solved the structure of the human liver receptor homolog-1 DNA binding domain bound to the same element. We explore the structural elements that govern Oct4 recognition by these two nuclear receptors.

  19. Nuclear Receptors in Drug Metabolism, Drug Response and Drug Interactions

    Directory of Open Access Journals (Sweden)

    Chandra Prakash

    2015-12-01

    Full Text Available Orally delivered small-molecule therapeutics are metabolized in the liver and intestine by phase I and phase II drug-metabolizing enzymes (DMEs, and transport proteins coordinate drug influx (phase 0 and drug/drug-metabolite efflux (phase III. Genes involved in drug metabolism and disposition are induced by xenobiotic-activated nuclear receptors (NRs, i.e. PXR (pregnane X receptor and CAR (constitutive androstane receptor, and by the 1α, 25-dihydroxy vitamin D3-activated vitamin D receptor (VDR, due to transactivation of xenobiotic-response elements (XREs present in phase 0-III genes. Additional NRs, like HNF4-α, FXR, LXR-α play important roles in drug metabolism in certain settings, such as in relation to cholesterol and bile acid metabolism. The phase I enzymes CYP3A4/A5, CYP2D6, CYP2B6, CYP2C9, CYP2C19, CYP1A2, CYP2C8, CYP2A6, CYP2J2, and CYP2E1 metabolize >90% of all prescription drugs, and phase II conjugation of hydrophilic functional groups (with/without phase I modification facilitates drug clearance. The conjugation step is mediated by broad-specificity transferases like UGTs, SULTs, GSTs. This review delves into our current understanding of PXR/CAR/VDR-mediated regulation of DME and transporter expression, as well as effects of single nucleotide polymorphism (SNP and epigenome (specified by promoter methylation, histone modification, microRNAs, long non coding RNAs on the expression of PXR/CAR/VDR and phase 0-III mediators, and their impacts on variable drug response. Therapeutic agents that target epigenetic regulation and the molecular basis and consequences (overdosing, underdosing, or beneficial outcome of drug-drug/drug-food/drug-herb interactions are also discussed. Precision medicine requires understanding of a drug's impact on DME and transporter activity and their NR-regulated expression in order to achieve optimal drug efficacy without adverse drug reactions. In future drug screening, new tools such as humanized mouse

  20. Differential modulation of androgen receptor transcriptional activity by the nuclear receptor co-repressor (N-CoR).

    NARCIS (Netherlands)

    C.A. Berrevoets (Cor); A. Umar (Arzu); A.O. Brinkmann (Albert); J. Trapman (Jan)

    2004-01-01

    textabstractAntiandrogens are widely used agents in the treatment of prostate cancer, as inhibitors of AR (androgen receptor) action. Although the precise mechanism of antiandrogen action is not yet elucidated, recent studies indicate the involvement of nuclear receptor co-represso

  1. The nuclear receptor gene family in the Pacific oyster, Crassostrea gigas, contains a novel subfamily group.

    Science.gov (United States)

    Vogeler, Susanne; Galloway, Tamara S; Lyons, Brett P; Bean, Tim P

    2014-05-15

    Nuclear receptors are a superfamily of transcription factors important in key biological, developmental and reproductive processes. Several of these receptors are ligand- activated and through their ability to bind endogenous and exogenous ligands, are potentially vulnerable to xenobiotics. Molluscs are key ecological species in defining aquatic and terrestrial habitats and are sensitive to xenobiotic compounds in the environment. However, the understanding of nuclear receptor presence, function and xenobiotic disruption in the phylum Mollusca is limited. Here, forty-three nuclear receptor sequences were mined from the genome of the Pacific oyster, Crassostrea gigas. They include members of NR0-NR5 subfamilies, notably lacking any NR6 members. Phylogenetic analyses of the oyster nuclear receptors have been conducted showing the presence of a large novel subfamily group not previously reported, which is named NR1P. Homologues to all previous identified nuclear receptors in other mollusc species have also been determined including the putative heterodimer partner retinoid X receptor, estrogen receptor and estrogen related receptor. C. gigas contains a highly diverse set of nuclear receptors including a novel NR1 group, which provides important information on presence and evolution of this transcription factor superfamily in invertebrates. The Pacific oyster possesses two members of NR3, the sex steroid hormone receptor analogues, of which there are 9 in humans. This provides increasing evidence that steroid ligand specific expansion of this family is deuterostome specific. This new knowledge on divergence and emergence of nuclear receptors in C. gigas provides essential information for studying regulation of molluscan gene expression and the potential effects of xenobiotics.

  2. Regulation of Liver Energy Balance by the Nuclear Receptors Farnesoid X Receptor and Peroxisome Proliferator Activated Receptor α.

    Science.gov (United States)

    Kim, Kang Ho; Moore, David D

    2017-01-01

    The liver undergoes major changes in substrate utilization and metabolic output over the daily feeding and fasting cycle. These changes occur acutely in response to hormones such as insulin and glucagon, with rapid changes in signaling pathways mediated by protein phosphorylation and other post-translational modifications. They are also reflected in chronic alterations in gene expression in response to nutrient-sensitive transcription factors. Among these, the nuclear receptors farnesoid X receptor (FXR) and peroxisome proliferator activated receptor α (PPARα) provide an intriguing, coordinated response to maintain energy balance in the liver. FXR is activated in the fed state by bile acids returning to the liver, while PPARα is activated in the fasted state in response to the free fatty acids produced by adipocyte lipolysis or possibly other signals. Key Messages: Previous studies indicate that FXR and PPARα have opposing effects on each other's primary targets in key metabolic pathways including gluconeogenesis. Our more recent work shows that these 2 nuclear receptors coordinately regulate autophagy: FXR suppresses this pathway of nutrient and energy recovery, while PPARα activates it. Another recent study indicates that FXR activates the complement and coagulation pathway, while earlier studies identify this as a negative target of PPARα. Since secretion is a very energy- and nutrient-intensive process for hepatocytes, it is possible that FXR licenses it in the nutrient-rich fed state, while PPARα represses it to spare resources in the fasted state. Energy balance is a potential connection linking FXR and PPARα regulation of autophagy and secretion, 2 seemingly unrelated aspects of hepatocyte function. FXR and PPARα act coordinately to promote energy balance and homeostasis in the liver by regulating autophagy and potentially protein secretion. It is quite likely that their impact extends to additional pathways relevant to hepatic energy balance, and

  3. Nuclear exportin receptor CAS regulates the NPI-1-mediated nuclear import of HIV-1 Vpr.

    Directory of Open Access Journals (Sweden)

    Eri Takeda

    Full Text Available Vpr, an accessory protein of human immunodeficiency virus type 1, is a multifunctional protein that plays an important role in viral replication. We have previously shown that the region between residues 17 and 74 of Vpr (Vpr(N17C74 contained a bona fide nuclear localization signal and it is targeted Vpr(N17C74 to the nuclear envelope and then imported into the nucleus by importin α (Impα alone. The interaction between Impα and Vpr is important not only for the nuclear import of Vpr but also for HIV-1 replication in macrophages; however, it was unclear whether full-length Vpr enters the nucleus in a manner similar to Vpr(N17C74. This study investigated the nuclear import of full-length Vpr using the three typical Impα isoforms, Rch1, Qip1 and NPI-1, and revealed that full-length Vpr is selectively imported by NPI-1, but not Rch1 and Qip1, after it makes contact with the perinuclear region in digitonin-permeabilized cells. A binding assay using the three Impα isoforms showed that Vpr bound preferentially to the ninth armadillo repeat (ARM region (which is also essential for the binding of CAS, the export receptor for Impα in all three isoforms. Comparison of biochemical binding affinities between Vpr and the Impα isoforms using surface plasmon resonance analysis demonstrated almost identical values for the binding of Vpr to the full-length isoforms and to their C-terminal domains. By contrast, the data showed that, in the presence of CAS, Vpr was released from the Vpr/NPI-1 complex but was not released from Rch1 or Qip1. Finally, the NPI-1-mediated nuclear import of Vpr was greatly reduced in semi-intact CAS knocked-down cells and was recovered by the addition of exogenous CAS. This report is the first to show the requirement for and the regulation of CAS in the functioning of the Vpr-Impα complex.

  4. Computational characterization of modes of transcriptional regulation of nuclear receptor genes.

    Directory of Open Access Journals (Sweden)

    Yogita Sharma

    Full Text Available BACKGROUND: Nuclear receptors are a large structural class of transcription factors that act with their co-regulators and repressors to maintain a variety of biological and physiological processes such as metabolism, development and reproduction. They are activated through the binding of small ligands, which can be replaced by drug molecules, making nuclear receptors promising drug targets. Transcriptional regulation of the genes that encode them is central to gaining a deeper understanding of the diversity of their biochemical and biophysical roles and their role in disease and therapy. Even though they share evolutionary history, nuclear receptor genes have fundamentally different expression patterns, ranging from ubiquitously expressed to tissue-specific and spatiotemporally complex. However, current understanding of regulation in nuclear receptor gene family is still nascent. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigate the relationship between long-range regulation of nuclear receptor family and their known functionality. Towards this goal, we identify the nuclear receptor genes that are potential targets based on counts of highly conserved non-coding elements. We validate our results using publicly available expression (RNA-seq and histone modification (ChIP-seq data from the ENCODE project. We find that nuclear receptor genes involved in developmental roles show strong evidence of long-range mechanism of transcription regulation with distinct cis-regulatory content they feature clusters of highly conserved non-coding elements distributed in regions spanning several Megabases, long and multiple CpG islands, bivalent promoter marks and statistically significant higher enrichment of enhancer mark around their gene loci. On the other hand nuclear receptor genes that are involved in tissue-specific roles lack these features, having simple transcriptional controls and a greater variety of mechanisms for producing paralogs. We

  5. Nuclear and extra-nuclear effects of retinoid acid receptors: how they are interconnected.

    Science.gov (United States)

    Piskunov, Aleksandr; Al Tanoury, Ziad; Rochette-Egly, Cécile

    2014-01-01

    The nuclear retinoic acid receptors (RAR α, β and γ) and their isoforms are ligand-dependent regulators of transcription Transcription , which mediate the effects of all-trans retinoic acid (RA), the active endogenous metabolite of Vitamin A. They heterodimerize with Retinoid X Receptors (RXRs α, β and γ), and regulate the expression of a battery of target genes Target genes involved in cell growth and differentiation Differentiation . During the two last decades, the description of the crystallographic structures of RARs, the characterization of the polymorphic response elements of their target genes Target genes , and the identification of the multiprotein complexes involved in their transcriptional activity have provided a wealth of information on their pleiotropic effects. However, the regulatory scenario became even more complicated once it was discovered that RARs are phosphoproteins and that RA can activate kinase signaling cascades via a pool of RARs present in membrane lipid rafts. Now it is known that these RA-activated kinases Kinases translocate to the nucleus where they phosphorylate RARs and other retinoid signaling factors. The phosphorylation Phosphorylation state of the RARs dictates whether the transcriptional programs which are known to be induced by RA are facilitated and/or switched on. Thus, kinase signaling pathways appear to be crucial for fine-tuning the appropriate physiological activity of RARs.

  6. The transcriptional coactivators p/CIP and SRC-1 control insulin resistance through IRS1 in obesity models.

    Directory of Open Access Journals (Sweden)

    Zhiyong Wang

    Full Text Available Three p160 family members, p/CIP, SRC1, and TIF2, have been identified as transcriptional coactivators for nuclear hormone receptors and other transcription factors in vitro. In a previous study, we reported initial characterization of the obesity-resistant phenotypes of p/CIP and SRC-1 double knockout (DKO mice, which exhibit increased energy expenditure, and suggested that nuclear hormone receptor target genes were involved in these phenotypes. In this study, we demonstrate that p/CIP and SRC1 control insulin signaling in a cell-autonomous manner both in vitro and in vivo. Genetic deletion of p/CIP and SRC-1 increases glucose uptake and enhances insulin sensitivity in both regular chow- and high fat diet-fed DKO mice despite increased food intake. Interestingly, we discover that loss of p/CIP and SRC-1 results in resistance to age-related obesity and glucose intolerance. We show that expression levels of a key insulin signaling component, insulin receptor substrate 1 (IRS1, are significantly increased in two cell lines representing fat and muscle lineages with p/CIP and SRC-1 deletions and in white adipose tissue and skeletal muscle of DKO mice; this may account for increased glucose metabolism and insulin sensitivity. This is the first evidence that the p160 coactivators control insulin signaling and glucose metabolism through IRS1. Therefore, our studies indicate that p/CIP and SRC-1 are potential therapeutic targets not only for obesity but also for diabetes.

  7. Transcriptional integration of metabolism by the nuclear sterol-activated receptors LXR and FXR.

    Science.gov (United States)

    Calkin, Anna C; Tontonoz, Peter

    2012-03-14

    Nuclear receptors are integrators of hormonal and nutritional signals, mediating changes to metabolic pathways within the body. Given that modulation of lipid and glucose metabolism has been linked to diseases including type 2 diabetes, obesity and atherosclerosis, a greater understanding of pathways that regulate metabolism in physiology and disease is crucial. The liver X receptors (LXRs) and the farnesoid X receptors (FXRs) are activated by oxysterols and bile acids, respectively. Mounting evidence indicates that these nuclear receptors have essential roles, not only in the regulation of cholesterol and bile acid metabolism but also in the integration of sterol, fatty acid and glucose metabolism.

  8. Research resource: Comparative nuclear receptor atlas: basal and activated peritoneal B-1 and B-2 cells.

    Science.gov (United States)

    Diehl, Cody J; Barish, Grant D; Downes, Michael; Chou, Meng-Yun; Heinz, Sven; Glass, Christopher K; Evans, Ronald M; Witztum, Joseph L

    2011-03-01

    Naïve murine B cells are typically divided into three subsets based on functional and phenotypic characteristics: innate-like B-1 and marginal zone B cells vs. adaptive B-2 cells, also known as follicular or conventional B cells. B-1 cells, the innate-immune-like component of the B cell lineage are the primary source of natural antibodies and have been shown to modulate autoimmune diseases, human B-cell leukemias, and inflammatory disorders such as atherosclerosis. On the other hand, B-2 cells are the principal mediators of the adaptive humoral immune response and represent an important pharmacological target for various conditions including rheumatoid arthritis, lupus erythematosus, and lymphomas. Using the resources of the Nuclear Receptor Signaling Atlas program, we used quantitative real-time PCR to assess the complement of the 49 murine nuclear receptor superfamily expressed in quiescent and toll-like receptor (TLR)-stimulated peritoneal B-1 and B-2 cells. We report the expression of 24 nuclear receptors in basal B-1 cells and 25 nuclear receptors in basal B-2 cells, with, in some cases, dramatic changes in response to TLR 4 or TLR 2/1 stimulation. Comparative nuclear receptor profiling between B-1 and peritoneal B-2 cells reveals a highly concordant expression pattern, albeit at quantitatively dissimilar levels. We also found that splenic B cells express 23 nuclear receptors. This catalog of nuclear receptor expression in B-1 and B-2 cells provides data to be used to better understand the specific roles of nuclear receptors in B cell function, chronic inflammation, and autoimmune disease.

  9. Molecular pathways: the role of NR4A orphan nuclear receptors in cancer.

    LENUS (Irish Health Repository)

    Mohan, Helen M

    2012-06-15

    Nuclear receptors are of integral importance in carcinogenesis. Manipulation of classic ligand-activated nuclear receptors, such as estrogen receptor blockade in breast cancer, is an important established cancer therapy. Orphan nuclear receptors, such as nuclear family 4 subgroup A (NR4A) receptors, have no known natural ligand(s). These elusive receptors are increasingly recognized as molecular switches in cell survival and a molecular link between inflammation and cancer. NR4A receptors act as transcription factors, altering expression of downstream genes in apoptosis (Fas-ligand, TRAIL), proliferation, DNA repair, metabolism, cell migration, inflammation (interleukin-8), and angiogenesis (VEGF). NR4A receptors are modulated by multiple cell-signaling pathways, including protein kinase A\\/CREB, NF-κB, phosphoinositide 3-kinase\\/AKT, c-jun-NH(2)-kinase, Wnt, and mitogen-activated protein kinase pathways. NR4A receptor effects are context and tissue specific, influenced by their levels of expression, posttranslational modification, and interaction with other transcription factors (RXR, PPAR-Υ). The subcellular location of NR4A "nuclear receptors" is also important functionally; novel roles have been described in the cytoplasm where NR4A proteins act both indirectly and directly on the mitochondria to promote apoptosis via Bcl-2. NR4A receptors are implicated in a wide variety of malignancies, including breast, lung, colon, bladder, and prostate cancer; glioblastoma multiforme; sarcoma; and acute and\\/or chronic myeloid leukemia. NR4A receptors modulate response to conventional chemotherapy and represent an exciting frontier for chemotherapeutic intervention, as novel agents targeting NR4A receptors have now been developed. This review provides a concise clinical overview of current knowledge of NR4A signaling in cancer and the potential for therapeutic manipulation.

  10. PGC-1 coactivators in the control of energy metabolism

    Institute of Scientific and Technical Information of China (English)

    Chang Liu; Jiandie D.Lin

    2011-01-01

    Chronic disruption of energy balance, where energy intake exceeds expenditure, is a major risk factor for the development of metabolic syndrome. The latter is characterized by a constellation of symptoms including obesity, dyslipidemia, insulin resistance, hypertension, and nonalcoholic fatty liver disease. Altered expression of genes involved in glucose and lipid metabolism as well as mitochondrial oxidative phosphorylation has been implicated in the pathogenesis of these disorders. The peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) family of transcriptional coactivators is emerging as a hub linking nutritional and hormonal signals and energy metabolism. PGC-1а and PGC-1β are highly responsive to environmental cues and coordinate metabolic gene pro- grams through interaction with transcription factors and chromatin-remodeling proteins. PGC-1а has been implicated in the pathogenic conditions including obesity, type 2 diabetes, neurodegeneration, and cardiomyopathy, whereas PGC-1β plays an important role in plasma iipoprotein homeostasis and serves as a hepatic target for niacin, a potent hypotriglyceridemic drug. Here, we review recent advances in the identification of physiological and pathophysiological contexts involving PGC-1 coactivators, and also discuss their implications for therapeutic development.

  11. Orphan nuclear receptor Errγ induces C-reactive protein gene expression through induction of ER-bound Bzip transmembrane transcription factor CREBH.

    Directory of Open Access Journals (Sweden)

    Jagannath Misra

    Full Text Available The orphan nuclear receptor estrogen-related receptor-γ (ERRγ is a constitutively active transcription factor regulating genes involved in several important cellular processes, including hepatic glucose metabolism, alcohol metabolism, and the endoplasmic reticulum (ER stress response. cAMP responsive element-binding protein H (CREBH is an ER-bound bZIP family transcription factor that is activated upon ER stress and regulates genes encoding acute-phase proteins whose expression is increased in response to inflammation. Here, we report that ERRγ directly regulates CREBH gene expression in response to ER stress. ERRγ bound to the ERRγ response element (ERRE in the CREBH promoter. Overexpression of ERRγ by adenovirus significantly increased expression of CREBH as well as C-reactive protein (CRP, whereas either knockdown of ERRγ or inhibition of ERRγ by ERRγ specific inverse agonist, GSK5182, substantially inhibited ER stress-mediated induction of CREBH and CRP. The transcriptional coactivator PGC1α was required for ERRγ mediated induction of the CREBH gene as demonstrated by the chromatin immunoprecipitation (ChIP assay showing binding of both ERRγ and PGC1α on the CREBH promoter. The ChIP assay also revealed that histone H3 and H4 acetylation occurred at the ERRγ and PGC1α binding site. Moreover, chronic alcoholic hepatosteatosis, as well as the diabetic obese condition significantly increased CRP gene expression, and this increase was significantly attenuated by GSK5182 treatment. We suggest that orphan nuclear receptor ERRγ directly regulates the ER-bound transcription factor CREBH in response to ER stress and other metabolic conditions.

  12. Gold Nanoparticles Functionalized with Peptides for Specific Affinity Aggregation Assays of Estrogen Receptors and Their Agonists

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Takatsuji

    2012-04-01

    Full Text Available Nuclear receptors regulate the transcription of genes and various functions such as development, differentiation, homeostasis, and behavior by formation of complexes with ligand and co-activator. Recent findings have shown that agonists of a ligand may have a toxic effect on cellular/tissular function through improper activation of nuclear receptors. In this study, a simple assay system of hetero-complexes of three different molecules (estrogen receptor, ligand, and co-activator peptide has been developed. This assay system employs functionalized gold nanoparticles (GNPs: 15 nm in diameter. The surfaces of the GNPs were modified by a 12- or 20-amino-acid peptide that contains the sequence of co-activator for activating nuclear receptor by an agonist ligand. Owing to the affinity of the peptide, the functionalized GNPs aggregate faster when the nuclear receptor and the agonist ligand are also present. The aggregation of GNPs can be identified by shifts in adsorption spectrum, which give information about the specificity of agonist ligands. Similarly, this spectrum shift can measure concentration of known agonist ligand. This simple agonist screening will be employed as high through-put analysis (HTA in the discovery of drugs that act through nuclear receptors.

  13. A Boolean Network Model of Nuclear Receptor Mediated Cell Cycle Progression (S)

    Science.gov (United States)

    Nuclear receptors (NRs) are ligand-activated transcription factors that regulate a broad range of cellular processes. Hormones, lipids and xenobiotics have been shown to activate NRs with a range of consequences on development, metabolism, oxidative stress, apoptosis, and prolif...

  14. A Boolean Network Model of Nuclear Receptor Mediated Cell Cycle Progression

    Science.gov (United States)

    Nuclear receptors (NRs) are ligand-activated transcription factors that regulate a broad range of cellular processes. Hormones, lipids and xenobiotics have been shown to activate NRs with a range of consequences on development, metabolism, oxidative stress, apoptosis, and prolif...

  15. Transcriptional Crosstalk between Nuclear Receptors and Cytokine Signal Transduction Pathways in Immunity

    Institute of Scientific and Technical Information of China (English)

    Lihua Wang; Xiaohu Zhang; William L. Farrar; Xiaoyi Yang

    2004-01-01

    The nuclear receptor superfamily and the transcriptional factors associated with cytokines are inherently different families of signaling molecules and activate gene transcription by binding to their respective responsive element. However, it has become increasingly clear from our works and others that nuclear receptors are important regulators of cytokine production and function through complex and varied interactions between these distinct transcriptional factors. This review provides a general overview of the mechanism of action of nuclear receptors and their transcriptional crosstalk with transcriptional factors associated with cytokine transduction pathways. One of the most important mechanistic aspects is protein to protein interaction through a direct or co-regulator-mediated indirect manner. Such crosstalk is crucially involved in physiological and therapeutic roles of nuclear receptors and their ligands in immunity,inflammation and cytokine-related tumors. Cellular & Molecular Immunology. 2004;1(6):416-424.

  16. Evidence for triclosan-induced activation of human and rodent xenobiotic nuclear receptors

    Science.gov (United States)

    The bacteriostat triclosan (2,4,40-trichloro-20-hydroxydiphenylether) (TCS) decreases rat serum thyroxine via putative nuclear receptor (NR) interaction(s) and subsequent transcriptional up-regulation of hepatic catabolism and clearance. However, due to the evolutionary divergenc...

  17. LASSO-ing Potential Nuclear Receptor Agonists and Antagonists: A New Computational Method for Database Screening

    Science.gov (United States)

    Nuclear receptors (NRs) are important biological macromolecular transcription factors that are implicated in multiple biological pathways and may interact with other xenobiotics that are endocrine disruptors present in the environment. Examples of important NRs include the androg...

  18. Nuclear receptors and endocrine disruptors in fetal and neonatal testes: a gapped landscape.

    Directory of Open Access Journals (Sweden)

    Virginie eRouiller-Fabre

    2015-05-01

    Full Text Available During the last decades, many studies reported that male reproductive disorders are increasing among humans. It is currently acknowledged that these abnormalities can result from fetal exposure to environmental chemicals that are progressively becoming more concentrated and widespread in our environment. Among the chemicals present in the environment (air, water, food and many consumer products, several can act as endocrine disrupting compounds (EDCs, thus interfering with the endocrine system. Phthalates, bisphenol A (BPA and diethylstilbestrol (DES have been largely incriminated, particularly during the fetal and neonatal period, due to their estrogenic and/or anti-androgenic properties. Indeed, many epidemiological and experimental studies have highlighted their deleterious impact on fetal and neonatal testis development. As EDCs can affect many different genomic and non-genomic pathways, the mechanisms underlying the adverse effects of EDC exposure are difficult to elucidate. Using literature data and results from our laboratory, in the present review we discuss the role of classical nuclear receptors (genomic pathway in the fetal and neonatal testis response to EDC exposure, particularly to phthalates, BPA and DES. Among the nuclear receptors we focused on some of the most likely candidates, such as peroxisome-proliferator activated receptor (PPAR, androgen receptor (AR, estrogen receptors (ERα and β, liver X receptors (LXR and small heterodimer partner (SHP. First, we describe the expression and potential functions (based on data from studies using receptor agonists and mouse knockout models of these nuclear receptors in the developing testis. Then, for each EDC studied, we summarize the main evidences indicating that the reprotoxic effect of each EDC under study is mediated through a specific nuclear receptor(s. We also point-out the involvement of other receptors and nuclear receptor-independent pathways.

  19. Nuclear receptors and endocrine disruptors in fetal and neonatal testes: a gapped landscape.

    Science.gov (United States)

    Rouiller-Fabre, Virginie; Guerquin, Marie Justine; N'Tumba-Byn, Thierry; Muczynski, Vincent; Moison, Delphine; Tourpin, Sophie; Messiaen, Sébastien; Habert, René; Livera, Gabriel

    2015-01-01

    During the last decades, many studies reported that male reproductive disorders are increasing among humans. It is currently acknowledged that these abnormalities can result from fetal exposure to environmental chemicals that are progressively becoming more concentrated and widespread in our environment. Among the chemicals present in the environment (air, water, food, and many consumer products), several can act as endocrine disrupting compounds (EDCs), thus interfering with the endocrine system. Phthalates, bisphenol A (BPA), and diethylstilbestrol (DES) have been largely incriminated, particularly during the fetal and neonatal period, due to their estrogenic and/or anti-androgenic properties. Indeed, many epidemiological and experimental studies have highlighted their deleterious impact on fetal and neonatal testis development. As EDCs can affect many different genomic and non-genomic pathways, the mechanisms underlying the adverse effects of EDC exposure are difficult to elucidate. Using literature data and results from our laboratory, in the present review, we discuss the role of classical nuclear receptors (genomic pathway) in the fetal and neonatal testis response to EDC exposure, particularly to phthalates, BPA, and DES. Among the nuclear receptors, we focused on some of the most likely candidates, such as peroxisome-proliferator activated receptor (PPAR), androgen receptor (AR), estrogen receptors (ERα and β), liver X receptors (LXR), and small heterodimer partner (SHP). First, we describe the expression and potential functions (based on data from studies using receptor agonists and mouse knockout models) of these nuclear receptors in the developing testis. Then, for each EDC studied, we summarize the main evidences indicating that the reprotoxic effect of each EDC under study is mediated through a specific nuclear receptor(s). We also point-out the involvement of other receptors and nuclear receptor-independent pathways.

  20. Breast cancer prognosis predicted by nuclear receptor-coregulator networks.

    Science.gov (United States)

    Doan, Tram B; Eriksson, Natalie A; Graham, Dinny; Funder, John W; Simpson, Evan R; Kuczek, Elizabeth S; Clyne, Colin; Leedman, Peter J; Tilley, Wayne D; Fuller, Peter J; Muscat, George E O; Clarke, Christine L

    2014-07-01

    Although molecular signatures based on transcript expression in breast cancer samples have provided new insights into breast cancer classification and prognosis, there are acknowledged limitations in current signatures. To provide rational, pathway-based signatures of disrupted physiology in cancer tissues that may be relevant to prognosis, this study has directly quantitated changed gene expression, between normal breast and cancer tissue, as a basis for signature development. The nuclear receptor (NR) family of transcription factors, and their coregulators, are fundamental regulators of every aspect of metazoan life, and were rigorously quantified in normal breast tissues and ERα positive and ERα negative breast cancers. Coregulator expression was highly correlated with that of selected NR in normal breast, particularly from postmenopausal women. These associations were markedly decreased in breast cancer, and the expression of the majority of coregulators was down-regulated in cancer tissues compared with normal. While in cancer the loss of NR-coregulator associations observed in normal breast was common, a small number of NR (Rev-ERBβ, GR, NOR1, LRH-1 and PGR) acquired new associations with coregulators in cancer tissues. Elevated expression of these NR in cancers was associated with poorer outcome in large clinical cohorts, as well as suggesting the activation of ERα -related, but ERα-independent, pathways in ERα negative cancers. In addition, the combined expression of small numbers of NR and coregulators in breast cancer was identified as a signature predicting outcome in ERα negative breast cancer patients, not linked to proliferation and with predictive power superior to existing signatures containing many more genes. These findings highlight the power of predictive signatures derived from the quantitative determination of altered gene expression between normal breast and breast cancers. Taken together, the findings of this study identify networks

  1. Transcriptomine, a web resource for nuclear receptor signaling transcriptomes.

    Science.gov (United States)

    Ochsner, Scott A; Watkins, Christopher M; McOwiti, Apollo; Xu, Xueping; Darlington, Yolanda F; Dehart, Michael D; Cooney, Austin J; Steffen, David L; Becnel, Lauren B; McKenna, Neil J

    2012-09-01

    The nuclear receptor (NR) superfamily of ligand-regulated transcription factors directs ligand- and tissue-specific transcriptomes in myriad developmental, metabolic, immunological, and reproductive processes. The NR signaling field has generated a wealth of genome-wide expression data points, but due to deficits in their accessibility, annotation, and integration, the full potential of these studies has not yet been realized. We searched public gene expression databases and MEDLINE for global transcriptomic datasets relevant to NRs, their ligands, and coregulators. We carried out extensive, deep reannotation of the datasets using controlled vocabularies for RNA Source and regulating molecule and resolved disparate gene identifiers to official gene symbols to facilitate comparison of fold changes and their significance across multiple datasets. We assembled these data points into a database, Transcriptomine (http://www.nursa.org/transcriptomine), that allows for multiple, menu-driven querying strategies of this transcriptomic "superdataset," including single and multiple genes, Gene Ontology terms, disease terms, and uploaded custom gene lists. Experimental variables such as regulating molecule, RNA Source, as well as fold-change and P value cutoff values can be modified, and full data records can be either browsed or downloaded for downstream analysis. We demonstrate the utility of Transcriptomine as a hypothesis generation and validation tool using in silico and experimental use cases. Our resource empowers users to instantly and routinely mine the collective biology of millions of previously disparate transcriptomic data points. By incorporating future transcriptome-wide datasets in the NR signaling field, we anticipate Transcriptomine developing into a powerful resource for the NR- and other signal transduction research communities.

  2. Natural compounds regulate energy metabolism by the modulating the activity of lipid-sensing nuclear receptors.

    Science.gov (United States)

    Goto, Tsuyoshi; Kim, Young-Il; Takahashi, Nobuyuki; Kawada, Teruo

    2013-01-01

    Obesity causes excess fat accumulation in various tissues, most notoriously in the adipose tissue, along with other insulin-responsive organs such as skeletal muscle and the liver, which predisposes an individual to the development of metabolic abnormalities. The molecular mechanisms underlying obesity-induced metabolic abnormalities have not been completely elucidated; however, in recent years, the search for therapies to prevent the development of obesity and obesity-associated metabolic disorders has increased. It is known that several nuclear receptors, when activated by specific ligands, regulate carbohydrate and lipid metabolism at the transcriptional level. The expression of lipid metabolism-related enzymes is directly regulated by the activity of various nuclear receptors via their interaction with specific response elements in promoters of those genes. Many natural compounds act as ligands of nuclear receptors and regulate carbohydrate and lipid metabolism by regulating the activities of these nuclear receptors. In this review, we describe our current knowledge of obesity, the role of lipid-sensing nuclear receptors in energy metabolism, and several examples of food factors that act as agonists or antagonists of nuclear receptors, which may be useful for the management of obesity and the accompanying energy metabolism abnormalities. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Bile Acid Nuclear Receptor Farnesoid X Receptor: Therapeutic Target for Nonalcoholic Fatty Liver Disease

    Science.gov (United States)

    Kim, Sun-Gi; Kim, Byung-Kwon; Kim, Kyumin

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) is one of the causes of fatty liver, occurring when fat is accumulated in the liver without alcohol consumption. NAFLD is the most common liver disorder in advanced countries. NAFLD is a spectrum of pathology involving hepatic steatosis with/without inflammation and nonalcoholic steatohepatitis with accumulation of hepatocyte damage and hepatic fibrosis. Recent studies have revealed that NAFLD results in the progression of cryptogenic cirrhosis that leads to hepatocarcinoma and cardiovascular diseases such as heart failure. The main causes of NAFLD have not been revealed yet, metabolic syndromes including obesity and insulin resistance are widely accepted for the critical risk factors for the pathogenesis of NAFLD. Nuclear receptors (NRs) are transcriptional factors that sense environmental or hormonal signals and regulate expression of genes, involved in cellular growth, development, and metabolism. Several NRs have been reported to regulate genes involved in energy and xenobiotic metabolism and inflammation. Among various NRs, farnesoid X receptor (FXR) is abundantly expressed in the liver and a key regulator to control various metabolic processes in the liver. Recent studies have shown that NAFLD is associated with inappropriate function of FXR. The impact of FXR transcriptional activity in NAFLD is likely to be potential therapeutic strategy, but still requires to elucidate underlying potent therapeutic mechanisms of FXR for the treatment of NAFLD. This article will focus the physiological roles of FXR and establish the correlation between FXR transcriptional activity and the pathogenesis of NAFLD. PMID:28029021

  4. Bile Acid Nuclear Receptor Farnesoid X Receptor: Therapeutic Target for Nonalcoholic Fatty Liver Disease

    Directory of Open Access Journals (Sweden)

    Sun-Gi Kim

    2016-12-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD is one of the causes of fatty liver, occurring when fat is accumulated in the liver without alcohol consumption. NAFLD is the most common liver disorder in advanced countries. NAFLD is a spectrum of pathology involving hepatic steatosis with/without inflammation and nonalcoholic steatohepatitis with accumulation of hepatocyte damage and hepatic fibrosis. Recent studies have revealed that NAFLD results in the progression of cryptogenic cirrhosis that leads to hepatocarcinoma and cardiovascular diseases such as heart failure. The main causes of NAFLD have not been revealed yet, metabolic syndromes including obesity and insulin resistance are widely accepted for the critical risk factors for the pathogenesis of NAFLD. Nuclear receptors (NRs are transcriptional factors that sense environmental or hormonal signals and regulate expression of genes, involved in cellular growth, development, and metabolism. Several NRs have been reported to regulate genes involved in energy and xenobiotic metabolism and inflammation. Among various NRs, farnesoid X receptor (FXR is abundantly expressed in the liver and a key regulator to control various metabolic processes in the liver. Recent studies have shown that NAFLD is associated with inappropriate function of FXR. The impact of FXR transcriptional activity in NAFLD is likely to be potential therapeutic strategy, but still requires to elucidate underlying potent therapeutic mechanisms of FXR for the treatment of NAFLD. This article will focus the physiological roles of FXR and establish the correlation between FXR transcriptional activity and the pathogenesis of NAFLD.

  5. Farnesoid X receptor, the bile acid sensing nuclear receptor, in liver regeneration

    Directory of Open Access Journals (Sweden)

    Guodong Li

    2015-03-01

    Full Text Available The liver is unique in regenerative potential, which could recover the lost mass and function after injury from ischemia and resection. The underlying molecular mechanisms of liver regeneration have been extensively studied in the past using the partial hepatectomy (PH model in rodents, where 2/3 PH is carried out by removing two lobes. The whole process of liver regeneration is complicated, orchestrated event involving a network of connected interactions, which still remain fully elusive. Bile acids (BAs are ligands of farnesoid X receptor (FXR, a nuclear receptor of ligand-activated transcription factor. FXR has been shown to be highly involved in liver regeneration. BAs and FXR not only interact with each other but also regulate various downstream targets independently during liver regeneration. Moreover, recent findings suggest that tissue-specific FXR also contributes to liver regeneration significantly. These novel findings suggest that FXR has much broader role than regulating BA, cholesterol, lipid and glucose metabolism. Therefore, these researches highlight FXR as an important pharmaceutical target for potential use of FXR ligands to regulate liver regeneration in clinic. This review focuses on the roles of BAs and FXR in liver regeneration and the current underlying molecular mechanisms which contribute to liver regeneration.

  6. Crystal Structures of the Nuclear Receptor, Liver Receptor Homolog 1, Bound to Synthetic Agonists.

    Science.gov (United States)

    Mays, Suzanne G; Okafor, C Denise; Whitby, Richard J; Goswami, Devrishi; Stec, Józef; Flynn, Autumn R; Dugan, Michael C; Jui, Nathan T; Griffin, Patrick R; Ortlund, Eric A

    2016-12-02

    Liver receptor homolog 1 (NR5A2, LRH-1) is an orphan nuclear hormone receptor that regulates diverse biological processes, including metabolism, proliferation, and the resolution of endoplasmic reticulum stress. Although preclinical and cellular studies demonstrate that LRH-1 has great potential as a therapeutic target for metabolic diseases and cancer, development of LRH-1 modulators has been difficult. Recently, systematic modifications to one of the few known chemical scaffolds capable of activating LRH-1 failed to improve efficacy substantially. Moreover, mechanisms through which LRH-1 is activated by synthetic ligands are entirely unknown. Here, we use x-ray crystallography and other structural methods to explore conformational changes and receptor-ligand interactions associated with LRH-1 activation by a set of related agonists. Unlike phospholipid LRH-1 ligands, these agonists bind deep in the pocket and do not interact with residues near the mouth nor do they expand the pocket like phospholipids. Unexpectedly, two closely related agonists with similar efficacies (GSK8470 and RJW100) exhibit completely different binding modes. The dramatic repositioning is influenced by a differential ability to establish stable face-to-face π-π-stacking with the LRH-1 residue His-390, as well as by a novel polar interaction mediated by the RJW100 hydroxyl group. The differing binding modes result in distinct mechanisms of action for the two agonists. Finally, we identify a network of conserved water molecules near the ligand-binding site that are important for activation by both agonists. This work reveals a previously unappreciated complexity associated with LRH-1 agonist development and offers insights into rational design strategies.

  7. Co-activation of NR2A and NR2B subunits induces resistance to fear extinction.

    Science.gov (United States)

    Leaderbrand, Katherine; Corcoran, Kevin A; Radulovic, Jelena

    2014-09-01

    Unpredictable stress is known to profoundly enhance susceptibility to fear and anxiety while reducing the ability to extinguish fear when threat is no longer present. Accordingly, partial aversive reinforcement, via random exposure to footshocks, induces fear that is resistant to extinction. Here we sought to determine the hippocampal mechanisms underlying susceptibility versus resistance to context fear extinction as a result of continuous (CR) and partial (PR) reinforcement, respectively. We focused on N-methyl-D-aspartate receptor (NMDAR) subunits 2A and B (NR2A and NR2B) as well as their downstream signaling effector, extracellular signal-regulated kinase (ERK), based on their critical role in the acquisition and extinction of fear. Pharmacological inactivation of NR2A, but not NR2B, blocked extinction after CR, whereas inactivation of NR2A, NR2B, or both subunits facilitated extinction after PR. The latter finding suggests that co-activation of NR2A and NR2B contributes to persistent fear following PR. In contrast to CR, PR increased membrane levels of ERK and NR2 subunits after the conditioning and extinction sessions, respectively. In parallel, nuclear activation of ERK was significantly reduced after the extinction session. Thus, co-activation and increased surface expression of NR2A and NR2B, possibly mediated by ERK, may cause persistent fear. These findings suggest that patients with post-traumatic stress disorder (PTSD) may benefit from antagonism of specific NR2 subunits.

  8. The PGC-1 coactivators promote an anti-inflammatory environment in skeletal muscle in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Eisele, Petra Sabine [Biozentrum, Division of Pharmacology/Neurobiology, University of Basel, CH-4056 Basel (Switzerland); Zurich Center for Integrative Human Physiology, University of Zurich, CH-8057 Zurich (Switzerland); Furrer, Regula; Beer, Markus [Biozentrum, Division of Pharmacology/Neurobiology, University of Basel, CH-4056 Basel (Switzerland); Handschin, Christoph, E-mail: christoph.handschin@unibas.ch [Biozentrum, Division of Pharmacology/Neurobiology, University of Basel, CH-4056 Basel (Switzerland); Zurich Center for Integrative Human Physiology, University of Zurich, CH-8057 Zurich (Switzerland)

    2015-08-28

    The peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is abundantly expressed in trained muscles and regulates muscle adaptation to endurance exercise. Inversely, mice lacking a functional PGC-1α allele in muscle exhibit reduced muscle functionality and increased inflammation. In isolated muscle cells, PGC-1α and the related PGC-1β counteract the induction of inflammation by reducing the activity of the nuclear factor κB (NFκB). We now tested the effects of these metabolic regulators on inflammatory reactions in muscle tissue of control and muscle-specific PGC-1α/-1β transgenic mice in vivo in the basal state as well as after an acute inflammatory insult. Surprisingly, we observed a PGC-1-dependent alteration of the cytokine profile characterized by an increase in anti-inflammatory factors and a strong suppression of the pro-inflammatory interleukin 12 (IL-12). In conclusion, the anti-inflammatory environment in muscle that is promoted by the PGC-1s might contribute to the beneficial effects of these coactivators on muscle function and provides a molecular link underlying the tight mutual regulation of metabolism and inflammation. - Highlights: • Muscle PGC-1s are insufficient to prevent acute systemic inflammation. • The muscle PGC-1s however promote a local anti-inflammatory environment. • This anti-inflammatory environment could contribute to the therapeutic effect of the PGC-1s.

  9. SRC-3/AIB1:transcriptional coactivator in oncogenesis

    Institute of Scientific and Technical Information of China (English)

    Jun YAN; Sophia Y TSAI; Ming-jer TSAI

    2006-01-01

    Steroid receptor coactivator-3 (SRC-3,also known as NCoA3,AIB1,p/CIP,RAC3,ACTR,and TRAM1) ,localized on a frequently amplified region,20q12,has been associated with multiple cancers,including breast,gastric and prostate cancers.Although SRC-3 has been implicated as an oncogene,compelling evidence has only recently emerged implicating it as a causal factor in the genesis of human cancers.Here,we summarize recent evidence that indicates aberrant SRC-3 expression is important in hormone-sensitive and -insensitive human cancers.

  10. Nuclear receptor 4a3 (nr4a3 regulates murine mast cell responses and granule content.

    Directory of Open Access Journals (Sweden)

    Gianni Garcia-Faroldi

    Full Text Available Nuclear receptor 4a3 (Nr4a3 is a transcription factor implicated in various settings such as vascular biology and inflammation. We have recently shown that mast cells dramatically upregulate Nuclear receptor 4a3 upon activation, and here we investigated the functional impact of Nuclear receptor 4a3 on mast cell responses. We show that Nuclear receptor 4a3 is involved in the regulation of cytokine/chemokine secretion in mast cells following activation via the high affinity IgE receptor. Moreover, Nuclear receptor 4a3 negatively affects the transcript and protein levels of mast cell tryptase as well as the mast cell's responsiveness to allergen. Together, these findings identify Nuclear receptor 4a3 as a novel regulator of mast cell function.

  11. The Roles of Orphan Nuclear Receptors in the Development and Function of the Immune System

    Institute of Scientific and Technical Information of China (English)

    Ivan Dzhagalov; Nu Zhang; You-Wen He

    2004-01-01

    Hormones and their receptors regulate cell growth, differentiation and apoptosis and also play important roles in immune function. Recent studies on the subfamily of the orphan nuclear receptors known as retinoid-acid related orphan receptors (ROR) have shed important insights on the roles of this group of nuclear proteins in the development and function of the immune system. RORα regulates inflammatory cytokine production in both innate and adaptive immune system while RORγ regulates the normal development of T lymphocyte repertoire and secondary lymphoid organs. Cellular & Molecular Immunology. 2004;1(6):401-407.

  12. The Roles of Orphan Nuclear Receptors in the Development and Function of the Immune System

    Institute of Scientific and Technical Information of China (English)

    IvanDzhagalov; NuZhang; You-WenHe

    2004-01-01

    Hormones and their receptors regulate cell growth, differentiation and apoptosis and also play important roles in immune function. Recent studies on the subfamily of the orphan nuclear receptors known as retinoid-acid related orphan receptors (ROR) have shed important insights on the roles of this group of nuclear proteins in the development and function of the immune system. RORα regulates inflammatory cytokine production in both innate and adaptive immune system while RORγ, regulates the normal development of T lymphocyte repertoire and secondary lymphoid organs. Cellular & Molecular Immunology. 2004;1(6):401-407.

  13. Identification of Modulators of the Nuclear Receptor Peroxisome Proliferator-Activated Receptor α (PPARα) in a Mouse Liver Gene Expression Compendium

    Science.gov (United States)

    The nuclear receptor family member peroxisome proliferator-activated receptor α (PPARα) is activated by therapeutic hypolipidemic drugs and environmentally-relevant chemicals to regulate genes involved in lipid transport and catabolism. Chronic activation of PPARα in rodents inc...

  14. Overexpression of transcriptional coactivator AIB1 promotes hepatocellular carcinoma progression by enhancing cell proliferation and invasiveness.

    Science.gov (United States)

    Xu, Y; Chen, Q; Li, W; Su, X; Chen, T; Liu, Y; Zhao, Y; Yu, C

    2010-06-10

    Amplified in breast cancer 1 (AIB1) is a transcriptional coactivator for nuclear receptors and other transcription factors. AIB1 has an important role in malignancy of several cancers such as breast and prostate cancers. However, its involvement in human hepatocellular carcinoma (HCC) progression remains unclear. Here, we found that AIB1 protein was overexpressed in 23 of 34 human HCC specimens (68%). Down-regulation of AIB1 reduced HCC cell proliferation, migration, invasion, colony formation ability and tumorigenic potential in nude mice. These phenotypic changes caused by AIB1 knockdown correlated with increased expression of the cell cycle inhibitor p21(Cip1/Waf1) and decreased Akt activation and the expression of proliferating cell nuclear antigen (PCNA) and matrix metallopeptidase MMP-9. In agreement with these findings, clinical AIB1-positive HCC expressed higher levels of PCNA than AIB1-negative HCC. A positive correlation was established between the levels of AIB1 protein and PCNA protein in HCC, suggesting that AIB1 may contribute to HCC cell proliferation. In addition, MMP-9 expression in AIB1-postive HCC was significantly higher than that in AIB1-negative HCC, suggesting that AIB1-postive HCC may be more invasive. Collectively, our results show that overexpression of AIB1 promotes human HCC progression by enhancing cell proliferation and invasiveness. Therefore, AIB1 is a master regulator of human HCC growth and might be a useful molecular target for HCC prognosis and treatment.

  15. 核受体转录辅激活蛋白:结构与功能%Nuclear Receptor Transcription Coactivators: Structure and Function

    Institute of Scientific and Technical Information of China (English)

    陈彬; 周度金

    2001-01-01

    @@核受体超家族大体可分为3个亚类:(1)由雌激素(estrogen,ER)、孕激素(proges-tin,PR)和糖皮质激素(glueocorticoid,GR)等类固醇激素受体构成的I类受体;(2)由甲状腺素(thyroid hormone,TR)、维生素D(vita-min D,VDR)、9-顺/反式视黄酸(9-cis/trans-retinoic acid,RXR,RAR)等构成的II类受体;(3)天然配体未知或不需要的孤儿受体。三类核受体的作用方式虽然不同,但在结构上却有共同的特点,它们的典型结构分为6个部分,即A、B、C、D、E和F区。其中,位于A/B区的AF-1和位于D区的AF-2结构域,与核受体转录活化密切相关。最近的研究表明核受体除直接参与基础转录机制外,还与一系列有效转录所必需的辅激活蛋白(coac-tivator)相互作用。

  16. PGC-1-一种新的核受体辅助活化因子%A New Transcriptional Coactivator of Nuclear Receptor, PGC-1

    Institute of Scientific and Technical Information of China (English)

    张春妮; 王沪旭

    2003-01-01

    PGC-1是一种新发现的核受体转录辅助活化因子.它具有多功能性,诱导线粒体增殖、呼吸、能量代谢及适应性产热,并与糖尿病、肥胖等密切相关.PGC-1具有调节多种核受体和转录因子活性的能力.此外,PGC-1不仅通过与核受体转录因子相互作用调节基因转录,也通过参与RNA后加工过程调节基因表达.

  17. Molecular Mechanisms Underlying the Link between Nuclear Receptor Function and Cholesterol Gallstone Formation

    Directory of Open Access Journals (Sweden)

    Mary Carmen Vázquez

    2012-01-01

    Full Text Available Cholesterol gallstone disease is highly prevalent in western countries, particularly in women and some specific ethnic groups. The formation of water-insoluble cholesterol crystals is due to a misbalance between the three major lipids present in the bile: cholesterol, bile salts, and phospholipids. Many proteins implicated in biliary lipid secretion in the liver are regulated by several transcription factors, including nuclear receptors LXR and FXR. Human and murine genetic, physiological, pathophysiological, and pharmacological evidence is consistent with the relevance of these nuclear receptors in gallstone formation. In addition, there is emerging data that also suggests a role for estrogen receptor ESR1 in abnormal cholesterol metabolism leading to gallstone disease. A better comprehension of the role of nuclear receptor function in gallstone formation may help to design new and more effective therapeutic strategies for this highly prevalent disease condition.

  18. Application of computational approaches to study signalling networks of nuclear and Tyrosine kinase receptors

    Directory of Open Access Journals (Sweden)

    Rebaï Ahmed

    2010-10-01

    Full Text Available Abstract Background Nuclear receptors (NRs and Receptor tyrosine kinases (RTKs are essential proteins in many cellular processes and sequence variations in their genes have been reported to be involved in many diseases including cancer. Although crosstalk between RTK and NR signalling and their contribution to the development of endocrine regulated cancers have been areas of intense investigation, the direct coupling of their signalling pathways remains elusive. In our understanding of the role and function of nuclear receptors on the cell membrane the interactions between nuclear receptors and tyrosine kinase receptors deserve further attention. Results We constructed a human signalling network containing nuclear receptors and tyrosine kinase receptors that identified a network topology involving eleven highly connected hubs. We further developed an integrated knowledge database, denominated NR-RTK database dedicated to human RTKs and NRs and their vertebrate orthologs and their interactions. These interactions were inferred using computational tools and those supported by literature evidence are indicated. NR-RTK database contains links to other relevant resources and includes data on receptor ligands. It aims to provide a comprehensive interaction map that identifies complex dynamics and potential crosstalk involved. Availability: NR-RTK database is accessible at http://www.bioinfo-cbs.org/NR-RTK/ Conclusions We infer that the NR-RTK interaction network is scale-free topology. We also uncovered the key receptors mediating the signal transduction between these two types of receptors. Furthermore, NR-RTK database is expected to be useful for researchers working on various aspects of the molecular basis of signal transduction by RTKs and NRs. Reviewers This article was reviewed by Professor Paul Harrison (nominated by Dr. Mark Gerstein, Dr. Arcady Mushegian and Dr. Anthony Almudevar.

  19. The nuclear import of the constitutive androstane receptor by importin/Ran-GTP systems.

    Science.gov (United States)

    Kanno, Yuichiro; Miyazaki, Yukari; Inouye, Yoshio

    2010-08-01

    The constitutive androstane receptor (CAR) is a member of the nuclear receptor superfamily. The CAR is normally located in the cytoplasmic compartment of untreated liver cells and translocates to the nucleus after exposure to phenobarbital (PB) or PB-like chemicals. Previously, we identified two nuclear localization signals (NLS) in the rat constitutive androstane/active receptor (CAR), NLS1, which is located in the hinge region, and NLS2, which overlaps with the ligand-binding domain. However, the nuclear import mechanism of CAR is unclear. In this study, we show that nuclear import of CAR is regulated by importin/Ran-GTP systems. The regulation of CAR nuclear import by a Ran-GTP concentration gradient was confirmed using the dominant negative, GTPase-deficient form of Ran (RanQ69L), suggesting the involvement of transport receptors of the importinbeta family. IPO13 was shown to be involved in the PB-mediated nuclear translocation of CAR, which was found to be susceptible to inhibition by a dominant negative mutant of IPO13 in primary hepatocytes. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  20. The estrogen receptor alpha nuclear localization sequence is critical for fulvestrant-induced degradation of the receptor.

    Science.gov (United States)

    Casa, Angelo J; Hochbaum, Daniel; Sreekumar, Sreeja; Oesterreich, Steffi; Lee, Adrian V

    2015-11-01

    Fulvestrant, a selective estrogen receptor down-regulator (SERD) is a pure competitive antagonist of estrogen receptor alpha (ERα). Fulvestrant binds ERα and reduces the receptor's half-life by increasing protein turnover, however, its mechanism of action is not fully understood. In this study, we show that removal of the ERα nuclear localization sequence (ERΔNLS) resulted in a predominantly cytoplasmic ERα that was degraded in response to 17-β-estradiol (E2) but was resistant to degradation by fulvestrant. ERΔNLS bound the ligands and exhibited receptor interaction similar to ERα, indicating that the lack of degradation was not due to disruption of these processes. Forcing ERΔNLS into the nucleus with a heterologous SV40-NLS did not restore degradation, suggesting that the NLS domain itself, and not merely receptor localization, is critical for fulvestrant-induced ERα degradation. Indeed, cloning of the endogenous ERα NLS onto the N-terminus of ERΔNLS significantly restored both its nuclear localization and turnover in response to fulvestrant. Moreover, mutation of the sumoylation targets K266 and K268 within the NLS impaired fulvestrant-induced ERα degradation. In conclusion, our study provides evidence for the unique role of the ERα NLS in fulvestrant-induced degradation of the receptor.

  1. PPP1R16A, the membrane subunit of protein phosphatase 1beta, signals nuclear translocation of the nuclear receptor constitutive active/androstane receptor.

    Science.gov (United States)

    Sueyoshi, Tatsuya; Moore, Rick; Sugatani, Junko; Matsumura, Yonehiro; Negishi, Masahiko

    2008-04-01

    Constitutive active/androstane receptor (CAR), a member of the nuclear steroid/thyroid hormone receptor family, activates transcription of numerous hepatic genes upon exposure to therapeutic drugs and environmental pollutants. Sequestered in the cytoplasm, this receptor signals xenobiotic exposure, such as phenobarbital (PB), by translocating into the nucleus. Unlike other hormone receptors, translocation can be triggered indirectly without binding to xenobiotics. We have now identified a membrane-associated subunit of protein phosphatase 1 (PPP1R16A, or abbreviated as R16A) as a novel CAR-binding protein. When CAR and R16A are coexpressed in mouse liver, CAR translocates into the nucleus. Close association of R16A and CAR molecule on liver membrane was shown by fluorescence resonance energy transfer (FRET) analysis using expressed yellow fluorescent protein (YFP)-CAR and CFP-R16A fusion proteins. R16A can form dimer through its middle region, where protein kinase A phosphorylation sites are recently identified. Translocation of CAR by R16A correlates with the ability of R16A to form an intermolecular interaction via the middle region. Moreover, this interaction is enhanced by PB treatment in mouse liver. R16A specifically interacted with PP1beta in HepG2 cells despite the highly conserved structure of PP1 family molecules. PP1beta activity was inhibited by R16A in vitro and coexpression of PP1beta in liver can prevent YFP-CAR translocation into mouse liver. Taken together, R16A at the membrane may mediate the PB signal to initiate CAR nuclear translocation, through a mechanism including its dimerization and inhibition of PP1beta activity, providing a novel model for the translocation of nuclear receptors in which direct interaction of ligands and the receptors may not be crucial.

  2. Osteoblast regulation via ligand-activated nuclear trafficking of the oxytocin receptor

    Science.gov (United States)

    Di Benedetto, Adriana; Sun, Li; Zambonin, Carlo G.; Tamma, Roberto; Nico, Beatrice; Calvano, Cosima D.; Colaianni, Graziana; Ji, Yaoting; Mori, Giorgio; Grano, Maria; Lu, Ping; Colucci, Silvia; Yuen, Tony; New, Maria I.; Zallone, Alberta; Zaidi, Mone

    2014-01-01

    We report that oxytocin (Oxt) receptors (Oxtrs), on stimulation by the ligand Oxt, translocate into the nucleus of osteoblasts, implicating this process in the action of Oxt on osteoblast maturation. Sequential immunocytochemistry of intact cells or isolated nucleoplasts stripped of the outer nuclear membrane showed progressive nuclear localization of the Oxtr; this nuclear translocation was confirmed by monitoring the movement of Oxtr–EGFP as well as by immunogold labeling. Nuclear Oxtr localization was conclusively shown by Western immunoblotting and MS of nuclear lysate proteins. We found that the passage of Oxtrs into the nucleus was facilitated by successive interactions with β-arrestins (Arrbs), the small GTPase Rab5, importin-β (Kpnb1), and transportin-1 (Tnpo1). siRNA-mediated knockdown of Arrb1, Arrb2, or Tnpo1 abrogated Oxt-induced expression of the osteoblast differentiation genes osterix (Sp7), Atf4, bone sialoprotein (Ibsp), and osteocalcin (Bglap) without affecting Erk phosphorylation. Likewise and again, without affecting pErk, inhibiting Arrb recruitment by mutating Ser rich clusters of the nuclear localization signal to Ala abolished nuclear import and Oxtr-induced gene expression. These studies define a previously unidentified mechanism for Oxtr action on bone and open possibilities for direct transcriptional modulation by nuclear G protein-coupled receptors. PMID:25378700

  3. Nuclear translocation of EGF receptor regulated by Epstein-Barr virus encoded latent membrane protein 1

    Institute of Scientific and Technical Information of China (English)

    TAO; Yongguang; SONG; Xin; TAN; Yunnian; LIN; Xiaofeng; ZH

    2004-01-01

    Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is considered to be the major oncogenic protein of EBV encoded proteins, and also it has always been the core of the oncogenic mechanism of EBV. Traditional receptor theory demonstrates that cell surface receptors exert biological functions on the membrane, which neither enter into the nucleus nor directly affect the transcription of the target genes. But, advanced studies on nuclear translocation of the epidermal growth factor receptor (EGFR) family have greatly developed our knowledge of the biological function of cell surface receptors. In this study, we used Tet-on LMP1 HNE2 cell line as a cell model, which is a dual-stable LMP1 integrated NPC cell line and the expression of LMP1 in which could be regulated by Tet system. We found that LMP1 could regulate the nuclear translocation of EGFR in a dose-dependent manner from both quantitative and qualitative levels through the Western blot analysis and the immunofluorescent analysis with a laser scanning confocal microscope. We further demonstrated that the nuclear localization sequence of EGFR played some roles in the location of the protein within the nucleus under LMP1 regulation, and the nuclear accumulation of EGFR regulated by LMP1 was in a ligand-independent manner. These findings provide a novel view that the regulation of LMP1 on the nuclear translocation of EGFR is critical for the process of nasopharyngeal carcinoma.

  4. Elevated copper impairs hepatic nuclear receptor function in Wilson’s disease

    Science.gov (United States)

    Wooton-Kee, Clavia Ruth; Jain, Ajay K.; Wagner, Martin; Grusak, Michael A.; Finegold, Milton J.; Lutsenko, Svetlana; Moore, David D.

    2015-01-01

    Wilson’s disease (WD) is an autosomal recessive disorder that results in accumulation of copper in the liver as a consequence of mutations in the gene encoding the copper-transporting P-type ATPase (ATP7B). WD is a chronic liver disorder, and individuals with the disease present with a variety of complications, including steatosis, cholestasis, cirrhosis, and liver failure. Similar to patients with WD, Atp7b–/– mice have markedly elevated levels of hepatic copper and liver pathology. Previous studies have demonstrated that replacement of zinc in the DNA-binding domain of the estrogen receptor (ER) with copper disrupts specific binding to DNA response elements. Here, we found decreased binding of the nuclear receptors FXR, RXR, HNF4α, and LRH-1 to promoter response elements and decreased mRNA expression of nuclear receptor target genes in Atp7b–/– mice, as well as in adult and pediatric WD patients. Excessive hepatic copper has been described in progressive familial cholestasis (PFIC), and we found that similar to individuals with WD, patients with PFIC2 or PFIC3 who have clinically elevated hepatic copper levels exhibit impaired nuclear receptor activity. Together, these data demonstrate that copper-mediated nuclear receptor dysfunction disrupts liver function in WD and potentially in other disorders associated with increased hepatic copper levels. PMID:26241054

  5. Nuclear receptor/microRNA circuitry links muscle fiber type to energy metabolism.

    Science.gov (United States)

    Gan, Zhenji; Rumsey, John; Hazen, Bethany C; Lai, Ling; Leone, Teresa C; Vega, Rick B; Xie, Hui; Conley, Kevin E; Auwerx, Johan; Smith, Steven R; Olson, Eric N; Kralli, Anastasia; Kelly, Daniel P

    2013-06-01

    The mechanisms involved in the coordinate regulation of the metabolic and structural programs controlling muscle fitness and endurance are unknown. Recently, the nuclear receptor PPARβ/δ was shown to activate muscle endurance programs in transgenic mice. In contrast, muscle-specific transgenic overexpression of the related nuclear receptor, PPARα, results in reduced capacity for endurance exercise. We took advantage of the divergent actions of PPARβ/δ and PPARα to explore the downstream regulatory circuitry that orchestrates the programs linking muscle fiber type with energy metabolism. Our results indicate that, in addition to the well-established role in transcriptional control of muscle metabolic genes, PPARβ/δ and PPARα participate in programs that exert opposing actions upon the type I fiber program through a distinct muscle microRNA (miRNA) network, dependent on the actions of another nuclear receptor, estrogen-related receptor γ (ERRγ). Gain-of-function and loss-of-function strategies in mice, together with assessment of muscle biopsies from humans, demonstrated that type I muscle fiber proportion is increased via the stimulatory actions of ERRγ on the expression of miR-499 and miR-208b. This nuclear receptor/miRNA regulatory circuit shows promise for the identification of therapeutic targets aimed at maintaining muscle fitness in a variety of chronic disease states, such as obesity, skeletal myopathies, and heart failure.

  6. Regulation of adipogenesis by nuclear receptor PPARγ is modulated by the histone demethylase JMJD2C

    OpenAIRE

    Lizcano Fernando; Romero Carolina; Diana Vargas

    2011-01-01

    A potential strategy to combat obesity and its associated complications involves modifying gene expression in adipose cells to reduce lipid accumulation. The nuclear receptor Peroxisome Proliferator-activated receptor gamma (PPARγ) is the master regulator of adipose cell differentiation and its functional activation is currently used as a therapeutic approach for Diabetes Mellitus type 2. However, total activation of PPARγ induces undesirable secondary effects that might be set with...

  7. Regulation of Estrogen Receptor Nuclear Export by Ligand-Induced and p38-Mediated Receptor Phosphorylation

    OpenAIRE

    Lee, Heehyoung; Bai, Wenlong

    2002-01-01

    Estrogen receptors are phosphoproteins which can be activated by ligands, kinase activators, or phosphatase inhibitors. Our previous study showed that p38 mitogen-activated protein kinase was involved in estrogen receptor activation by estrogens and MEKK1. Here, we report estrogen receptor-dependent p38 activation by estrogens in endometrial adenocarcinoma cells and in vitro and in vivo phosphorylation of the estrogen receptor α mediated through p38. The phosphorylation site was identified as...

  8. Pharmacology and toxicology of fibrates as hypolipidemic drugs mediated by nuclear receptor peroxisome proliferator—activated receptor

    Institute of Scientific and Technical Information of China (English)

    SugaT

    2002-01-01

    PPAR(peroxisome proliferator-activated receptor) is a family of nuclear receptor.In recent years,it has been focused for the discovery and development of new drugs which are mediated by PPARs.Fibrate hypolipidemic drugs are the specific and potent ligands to PPAR alpha and have been widely used for the treatment of hyperlipidemia.But these drugs induce hepatocarcinogenesis in rodent animals after the long-term administration.However,there are species differences on these phenomena which are not seen in mammals ioncluding human.To clarify the mechanism of carcinogenesis by these drugs in important for the evaluation of safety of these drugs in human.

  9. Role of estrogen receptor binding and transcriptional activity in the stimulation of hyperestrogenism and nuclear bodies.

    Science.gov (United States)

    Clark, J H; Hardin, J W; Padykula, H A; Cardasis, C A

    1978-06-01

    The effects of estradiol and nafoxidine on nuclear estrogen receptor binding, RNA polymerase activities, and uterine ultrastructure were studied. Animals were either injected with estradiol, implanted with estradiol/paraffin pellets, or injected with nafoxidine. Animals treated with nafoxidine or estradiol implants showed sustained long-term nuclear retention of estrogen receptor and increased nuclear RNA polymerase activities for up to 72 hr. A single injection of estradiol caused initial increases in these variables which returned to control levels by 24 hr after hormone treatment. Uterine tissue was examined by light and electron microscopy 72 hr after hormone treatments. Uteri from eith estradiol-implanted or nafoxidine-treated animals showed markedly increased hypertrophy of the luminal epithelial cells. Nuclei in sections of the uteri of these hyperestrogenized animals displayed a large number and wide array of nuclear bodies composed of a filamentous capsule and granular cores. We conclude that hyperestrogenization, a condition that eventually results in abnormal cell growth, is correlated with increased and sustained nuclear binding of the estrogen receptor, increased and sustained RNA polymerase activity, and the appearance of nuclear bodies.

  10. Daphnia HR96 is a promiscuous xenobiotic and endobiotic nuclear receptor

    Energy Technology Data Exchange (ETDEWEB)

    Karimullina, Elina [Environmental Toxicology Program, Clemson University, Clemson, SC 29634 (United States); Institute of Plant and Animal Ecology, Russian Academy of Sciences, Ural Branch, Yekaterinburg 620144 (Russian Federation); Li Yangchun; Ginjupalli, Gautam K. [Environmental Toxicology Program, Clemson University, Clemson, SC 29634 (United States); Baldwin, William S., E-mail: baldwin@clemson.edu [Environmental Toxicology Program, Clemson University, Clemson, SC 29634 (United States); Biological Sciences, Clemson University, Clemson, SC (United States)

    2012-07-15

    Daphnia pulex is the first crustacean to have its genome sequenced. The genome project provides new insight and data into how an aquatic crustacean may respond to environmental stressors, including toxicants. We cloned Daphnia pulex HR96 (DappuHR96), a nuclear receptor orthologous to the CAR/PXR/VDR group of nuclear receptors. In Drosophila melanogaster, (hormone receptor 96) HR96 responds to phenobarbital exposure and has been hypothesized as a toxicant receptor. Therefore, we set up a transactivation assay to test whether DappuHR96 is a promiscuous receptor activated by xenobiotics and endobiotics similar to the constitutive androstane receptor (CAR) and the pregnane X-receptor (PXR). Transactivation assays performed with a GAL4-HR96 chimera demonstrate that HR96 is a promiscuous toxicant receptor activated by a diverse set of chemicals such as pesticides, hormones, and fatty acids. Several environmental toxicants activate HR96 including estradiol, pyriproxyfen, chlorpyrifos, atrazine, and methane arsonate. We also observed repression of HR96 activity by chemicals such as triclosan, androstanol, and fluoxetine. Nearly 50% of the chemicals tested activated or inhibited HR96. Interestingly, unsaturated fatty acids were common activators or inhibitors of HR96 activity, indicating a link between diet and toxicant response. The omega-6 and omega-9 unsaturated fatty acids linoleic and oleic acid activated HR96, but the omega-3 unsaturated fatty acids alpha-linolenic acid and docosahexaenoic acid inhibited HR96, suggesting that these two distinct sets of lipids perform opposing roles in Daphnia physiology. This also provides a putative mechanism by which the ratio of dietary unsaturated fats may affect the ability of an organism to respond to a toxic insult. In summary, HR96 is a promiscuous nuclear receptor activated by numerous endo- and xenobiotics.

  11. Differential transcription of the orphan receptor RORbeta in nuclear extracts derived from Neuro2A and HeLa cells.

    NARCIS (Netherlands)

    Gawlas, K.; Stunnenberg, H.G.

    2001-01-01

    An important model system for studying the process leading to productive transcription is provided by the superfamily of nuclear receptors, which are for the most part ligand-controlled transcription factors. Over the past years several 'orphan' nuclear receptors have been isolated for which no liga

  12. Effect of clomiphene on nuclear estrogen receptor of the fallopian tube during ovum transport in rabbits.

    Science.gov (United States)

    Gupta, J S; Roy, S K

    1989-01-01

    The effect of clomiphene on nuclear estrogen receptors of the Fallopian tube during ovum transport in the rabbit has been studied. Nuclear binding capacity was observed in ampulla (A), ampullary-isthmic junction (AIJ), isthmus (I), uterine-isthmic junction (UIJ) and uterus (U). Receptor concentration decreased in all segments of the tube after administration of clomiphene in mated animals. The bindings are of high affinity and low capacity. Important alterations were observed during transport when compared to that of 14, 24, 34, 48, 72, 144 and 168 hr post-coitum (p.c). At 24 hr p.c binding increased only in I and decreased in A and AIJ. Retention of eggs at I at 24 hr p.c showed as increase in binding at I. Egg transport was accelerated and eggs reached prematurely in the uterus due to the influence of clomiphene. Binding in I remained constant from 48 hr p.c to 144 hr p.c but concurrently the binding level increased in U from 34 hr p.c. The elevation of nuclear estrogen receptor level was maximum at 24 hr p.c which coincided with increased plasma estrogen level. The result of such study showed that clomiphene depleted nuclear estrogen receptor complex in the fallopian tube before transfer to the uterus. Further, observation indicated that clomiphene acted directly on the rate of egg transport because of the variations in estrogen receptors during different time periods. Thus, clomiphene reduced the quantity of estrogen receptor i.e., insensitiveness to estrogen. The variations in estrogen binding to its receptor and plasma level at different post-coital periods are modulated by clomiphene resulting in the acceleration of egg transport and prevention of pregnancy.

  13. Retinoids induce integrin-independent lymphocyte adhesion through RAR-α nuclear receptor activity

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, Jarrett T.; Wang, Lei; Chen, Jianming; Metts, Meagan E.; Nasser, Taj A.; McGoldrick, Liam J. [Department of Biochemistry and Molecular Biology, The Brody School of Medicine at East Carolina University, Greenville, NC 27834 (United States); Bridges, Lance C., E-mail: bridgesl@ecu.edu [Department of Biochemistry and Molecular Biology, The Brody School of Medicine at East Carolina University, Greenville, NC 27834 (United States); East Carolina Diabetes and Obesity Institute, The Brody School of Medicine at East Carolina University, Greenville, NC 27834 (United States)

    2014-11-28

    Highlights: • Transcription and translation are required for retinoid-induced lymphocyte adhesion. • RAR activation is sufficient to induced lymphocyte cell adhesion. • Vitamin D derivatives inhibit RAR-prompted lymphocyte adhesion. • Adhesion occurs through a novel binding site within ADAM disintegrin domains. • RARα is a key nuclear receptor for retinoid-dependent lymphocyte cell adhesion. - Abstract: Oxidative metabolites of vitamin A, in particular all-trans-retinoic acid (atRA), have emerged as key factors in immunity by specifying the localization of immune cells to the gut. Although it is appreciated that isomers of retinoic acid activate the retinoic acid receptor (RAR) and retinoid X receptor (RXR) family of nuclear receptors to elicit cellular changes, the molecular details of retinoic acid action remain poorly defined in immune processes. Here we employ a battery of agonists and antagonists to delineate the specific nuclear receptors utilized by retinoids to evoke lymphocyte cell adhesion to ADAM (adisintegrin and metalloprotease) protein family members. We report that RAR agonism is sufficient to promote immune cell adhesion in both immortal and primary immune cells. Interestingly, adhesion occurs independent of integrin function, and mutant studies demonstrate that atRA-induced adhesion to ADAM members required a distinct binding interface(s) as compared to integrin recognition. Anti-inflammatory corticosteroids as well as 1,25-(OH){sub 2}D{sub 3}, a vitamin D metabolite that prompts immune cell trafficking to the skin, potently inhibited the observed adhesion. Finally, our data establish that induced adhesion was specifically attributable to the RAR-α receptor isotype. The current study provides novel molecular resolution as to which nuclear receptors transduce retinoid exposure into immune cell adhesion.

  14. SRA的RNA和蛋白质均有转录辅激活功能%Both the RNA and Protein of SRA Function as Transcription Co-activators

    Institute of Scientific and Technical Information of China (English)

    孙欢欢; 孙乐乐; 周鲁明; 庞秋香

    2011-01-01

    SRA is a steroid receptor co-activator. It has originally been characterized as only one noncoding transcript specifically co-activating steroid receptors. But the recent studies of SRA reveal that products of SRA gene have the unusual property to function both at the RNA and the protein levels. The cDNA sequences of SRA contain an identical 687 bp core sequence that is highly conserved in the evolution and is necessary for the transcriptional coactivity of steroid receptors. SRA-RNA has long been known to increase the transcriptional activation of multiple nuclear receptors. And its expression is suspected relevant to breast cancer. More recently, SRAP was proposed to have a similar function with its RNA transcript. But different from its RNA transcript, SRAP is recruited to specific promoter regions and acts as a transcriptional repressor. In this paper, we summarized the recent proceeding of researches in characteristics, expressions and functions of SRA and the possible mechanism and action mode on it.%类固醇受体激活物(steroid receptor activator,SRA)是一种类固醇受体辅激活物.最初的研究认为,SRA只存在RNA形式,不存在蛋白质形式.但是后来的研究发现,SRA是在RNA和蛋白质两个水平上发挥功能的分子,其cDNA序列存在687 bp保守的核心区域,该核心区域对其发挥转录共激活活性是必需的.SRA的RNA形式主要参与核受体的转录共激活作用,其表达与乳腺癌的发生有很大关系,SRA的蛋白质形式(steroid receptor activator protein,SRAP)也具有类似的功能.但是不同于RNA形式,SRAP可结合到特定基因的启动子区域,并起到阻遏物的作用.本文对SRA的特点、表达及功能等方面的最新研究进展及其可能的作用机制与作用形式进行概述.

  15. Nuclear thyroid hormone receptor binding in human mononuclear blood cells after goitre resection

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L E; Blichert-Toft, M

    1989-01-01

    Nuclear thyroxine and triiodothyronine receptor-binding in human mononuclear blood cells were examined in 14 euthyroid persons prior to and 1, 6, 24 and 53 weeks after goitre resection. One week after resection decreased serum T3 from 1.47 nmol/l to 1.14 nmol/l (P less than 0.05), FT4I from 103 a...

  16. Design principles of nuclear receptor signaling: How complex networking improves signal transduction

    NARCIS (Netherlands)

    A.N. Kolodkin (Alexey); F.J. Bruggeman (Frank); N. Plant (Nick); M.J. Moné (Martijn); B.M. Bakker (Barbara); M.J. Campbell (Moray); J.P.T.M. van Leeuwen (Hans); C. Carlberg (Carsten); J.L. Snoep (Jacky); H.V. Westerhoff (Hans)

    2010-01-01

    textabstractThe topology of nuclear receptor (NR) signaling is captured in a systems biological graphical notation. This enables us to identify a number of design aspects of the topology of these networks that might appear unnecessarily complex or even functionally paradoxical. In realistic kinetic

  17. Glucocorticoid receptor and nuclear factor kappa-b affect three-dimensional chromatin organization

    NARCIS (Netherlands)

    Kuznetsova, T.; Wang, S.Y.; Rao, N.A.; Mandoli, A.; Martens, J.H.; Rother, N; Aartse, A.; Groh, L.; Janssen-Megens, E.M.; Li, G.; Ruan, Y.; Logie, C.; Stunnenberg, H.G.

    2015-01-01

    BACKGROUND: The impact of signal-dependent transcription factors, such as glucocorticoid receptor and nuclear factor kappa-b, on the three-dimensional organization of chromatin remains a topic of discussion. The possible scenarios range from remodeling of higher order chromatin architecture by activ

  18. Activation of nuclear receptor Nur77 by 6-mercaptopurine protects against neointima formation

    NARCIS (Netherlands)

    Pires, N.M.M.; Pols, T.W.H.; Vries, M.R. de; Tiel, C.M.van; Bonta, P.I.; Vos, M.; Arkenbout, E.K.; Pannekoek, H.; Jukema, J.W.; Quax, P.H.A.; Vries, C.J.M. de

    2007-01-01

    BACKGROUND - Restenosis is a common complication after percutaneous coronary interventions and is characterized by excessive proliferation of vascular smooth muscle cells (SMCs). We have shown that the nuclear receptor Nur77 protects against SMC-rich lesion formation, and it has been demonstrated th

  19. Glucocorticoid receptor and nuclear factor kappa-b affect three-dimensional chromatin organization

    NARCIS (Netherlands)

    Kuznetsova, T.; Wang, S.Y.; Rao, N.A.; Mandoli, A.; Martens, J.H.; Rother, N; Aartse, A.; Groh, L.; Janssen-Megens, E.M.; Li, G.; Ruan, Y.; Logie, C.; Stunnenberg, H.G.

    2015-01-01

    BACKGROUND: The impact of signal-dependent transcription factors, such as glucocorticoid receptor and nuclear factor kappa-b, on the three-dimensional organization of chromatin remains a topic of discussion. The possible scenarios range from remodeling of higher order chromatin architecture by

  20. Design principles of nuclear receptor signaling : how complex networking improves signal transduction

    NARCIS (Netherlands)

    Kolodkin, Alexey N.; Bruggeman, Frank J.; Plant, Nick; Mone, Martijn J.; Bakker, Barbara M.; Campbell, Moray J.; van Leeuwen, Johannes P. T. M.; Carlberg, Carsten; Snoep, Jacky L.; Westerhoff, Hans V.

    2010-01-01

    The topology of nuclear receptor (NR) signaling is captured in a systems biological graphical notation. This enables us to identify a number of 'design' aspects of the topology of these networks that might appear unnecessarily complex or even functionally paradoxical. In realistic kinetic models of

  1. Orphan nuclear receptor TR4 and fibroblast growth factor 1 in metabolism

    NARCIS (Netherlands)

    Liu, Weilin

    2016-01-01

    Metabolic homeostasis is achieved, in part, through the coordinated activities of members of the Nuclear Receptor (NR) family, a superfamily of ligand-modulated transcription factors (TFs) that mediate responses to a wide range of lipophilic signaling molecules including lipids, steroids, retinoids,

  2. Activation of nuclear receptor Nur77 by 6-mercaptopurine protects against neointima formation

    NARCIS (Netherlands)

    Pires, N.M.M.; Pols, T.W.H.; Vries, M.R. de; Tiel, C.M.van; Bonta, P.I.; Vos, M.; Arkenbout, E.K.; Pannekoek, H.; Jukema, J.W.; Quax, P.H.A.; Vries, C.J.M. de

    2007-01-01

    BACKGROUND - Restenosis is a common complication after percutaneous coronary interventions and is characterized by excessive proliferation of vascular smooth muscle cells (SMCs). We have shown that the nuclear receptor Nur77 protects against SMC-rich lesion formation, and it has been demonstrated

  3. Design principles of nuclear receptor signaling: How complex networking improves signal transduction

    NARCIS (Netherlands)

    A.N. Kolodkin (Alexey); F.J. Bruggeman (Frank); N. Plant (Nick); M.J. Moné (Martijn); B.M. Bakker (Barbara); M.J. Campbell (Moray); J.P.T.M. van Leeuwen (Hans); C. Carlberg (Carsten); J.L. Snoep (Jacky); H.V. Westerhoff (Hans)

    2010-01-01

    textabstractThe topology of nuclear receptor (NR) signaling is captured in a systems biological graphical notation. This enables us to identify a number of design aspects of the topology of these networks that might appear unnecessarily complex or even functionally paradoxical. In realistic kinetic

  4. Regulation of bile acid synthesis by the nuclear receptor Rev-erb alpha

    NARCIS (Netherlands)

    Duez, Helene; Van Der Veen, Jelske N.; Duhem, Christian; Pourcet, Benoit; Touvier, Thierry; Fontaine, Coralie; Derudas, Bruno; Bauge, Eric; Havinga, Rick; Bloks, Vincent W.; Wolters, Henk; Van Der Sluijs, Fjodor H.; Vennstrom, Bjorn; Kuipers, Folkert; Staels, Bart

    2008-01-01

    Background & Aims: Conversion into bile acids represents an important route to remove excess cholesterol from the body. Rev-erb alpha is a nuclear receptor that participates as one of the clock genes in the control of circadian rhythmicity and plays a regulatory role in lipid metabolism and adipogen

  5. Dose-dependent difference of nuclear receptors involved in murine liver hypertrophy by piperonyl butoxide.

    Science.gov (United States)

    Sakamoto, Yohei; Yoshida, Midori; Tamura, Kei; Takahashi, Miwa; Kodama, Yukio; Inoue, Kaoru

    2015-12-01

    Nuclear receptors play important roles in chemically induced liver hypertrophy in rodents. To clarify the involvement of constitutive androstane receptor (CAR) and other nuclear receptors in mouse liver hypertrophy induced by different doses of piperonyl butoxide (PBO), wild-type and CAR-knockout mice were administered PBO (200, 1,000, or 5,000 ppm) in the basal diet for 1 week. Increased liver weight and diffuse hepatocellular hypertrophy were observed at 5,000 ppm for both genotypes, accompanied by increased Cyp3a11 mRNA and CYP3A protein expression, suggesting that CAR-independent pathway, possibly pregnane X receptor (PXR), plays a major role in the induction of hypertrophy. Moreover, wild-type mice at 5,000 ppm showed enhanced hepatocellular hypertrophy and strong positive staining for CYP2B in the centrilobular area, suggesting the localized contribution of CAR. At 1,000 ppm, only wild-type mice showed liver weight increase and centrilobular hepatocellular hypertrophy concurrent with elevated Cyp2b10 mRNA expression and strong CYP2B staining, indicating that CAR was essential at 1,000 ppm. We concluded that high-dose PBO induced hypertrophy via CAR and another pathway, while lower dose of PBO induced a pathway mediated predominantly by CAR. The dose-responsiveness on liver hypertrophy is important for understanding the involvement of nuclear receptors.

  6. Estrogen-related receptor α regulates osteoblast differentiation via Wnt/β-catenin signaling.

    Science.gov (United States)

    Auld, Kathryn L; Berasi, Stephen P; Liu, Yan; Cain, Michael; Zhang, Ying; Huard, Christine; Fukayama, Shoichi; Zhang, Jing; Choe, Sung; Zhong, Wenyan; Bhat, Bheem M; Bhat, Ramesh A; Brown, Eugene L; Martinez, Robert V

    2012-04-01

    Based on its homology to the estrogen receptor and its roles in osteoblast and chondrocyte differentiation, the orphan nuclear receptor estrogen-related receptor α (ERRα (ESRRA)) is an intriguing therapeutic target for osteoporosis and other bone diseases. The objective of this study was to better characterize the molecular mechanisms by which ERRα modulates osteoblastogenesis. Experiments from multiple systems demonstrated that ERRα modulates Wnt signaling, a crucial pathway for proper regulation of bone development. This was validated using a Wnt-luciferase reporter, where ERRα showed co-activator-dependent (peroxisome proliferator-activated receptor gamma co-activator 1α, PGC-1α) stimulatory effects. Interestingly, knockdown of ERRα expression also enhanced WNT signaling. In combination, these data indicated that ERRα could serve to either activate or repress Wnt signaling depending on the presence or absence of its co-activator PGC-1α. The observed Wnt pathway modulation was cell intrinsic and did not alter β-catenin nuclear translocation but was dependent on DNA binding of ERRα. We also found that expression of active ERRα correlated with Wnt pathway effects on osteoblastic differentiation in two cell types, consistent with a role for ERRα in modulating the Wnt pathway. In conclusion, this work identifies ERRα, in conjunction with co-activators such as PGC-1α, as a new regulator of the Wnt-signaling pathway during osteoblast differentiation, through a cell-intrinsic mechanism not affecting β-catenin nuclear translocation.

  7. Role of Nuclear Receptors in Central Nervous System Development and Associated Diseases

    Science.gov (United States)

    Olivares, Ana Maria; Moreno-Ramos, Oscar Andrés; Haider, Neena B.

    2015-01-01

    The nuclear hormone receptor (NHR) superfamily is composed of a wide range of receptors involved in a myriad of important biological processes, including development, growth, metabolism, and maintenance. Regulation of such wide variety of functions requires a complex system of gene regulation that includes interaction with transcription factors, chromatin-modifying complex, and the proper recognition of ligands. NHRs are able to coordinate the expression of genes in numerous pathways simultaneously. This review focuses on the role of nuclear receptors in the central nervous system and, in particular, their role in regulating the proper development and function of the brain and the eye. In addition, the review highlights the impact of mutations in NHRs on a spectrum of human diseases from autism to retinal degeneration. PMID:27168725

  8. Featured Article: Nuclear export of opioid growth factor receptor is CRM1 dependent.

    Science.gov (United States)

    Kren, Nancy P; Zagon, Ian S; McLaughlin, Patricia J

    2016-02-01

    Opioid growth factor receptor (OGFr) facilitates growth inhibition in the presence of its specific ligand opioid growth factor (OGF), chemically termed [Met(5)]-enkephalin. The function of the OGF-OGFr axis requires the receptor to translocate to the nucleus. However, the mechanism of nuclear export of OGFr is unknown. In this study, endogenous OGFr, as well as exogenously expressed OGFr-EGFP, demonstrated significant nuclear accumulation in response to leptomycin B (LMB), an inhibitor of CRM1-dependent nuclear export, suggesting that OGFr is exported in a CRM1-dependent manner. One consensus sequence for a nuclear export signal (NES) was identified. Mutation of the associated leucines, L217 L220 L223 and L225, to alanine resulted in decreased nuclear accumulation. NES-EGFP responded to LMB, indicating that this sequence is capable of functioning as an export signal in isolation. To determine why the sequence functions differently in isolation than as a full length protein, the localization of subNES was evaluated in the presence and absence of MG132, a potent inhibitor of proteosomal degradation. MG132 had no effect of subNES localization. The role of tandem repeats located at the C-terminus of OGFr was examined for their role in nuclear trafficking. Six of seven tandem repeats were removed to form deltaTR. DeltaTR localized exclusively to the nucleus indicating that the tandem repeats may contribute to the localization of the receptor. Similar to the loss of cellular proliferation activity (i.e. inhibition) recorded with subNES, deltaTR also demonstrated a significant loss of inhibitory activity indicating that the repeats may be integral to receptor function. These experiments reveal that OGFr contains one functional NES, L217 L220 L223 and L225 and can be exported from the nucleus in a CRM1-dependent manner.

  9. Nuclear hormone receptor NHR-49 controls fat consumption and fatty acid composition in C. elegans.

    Directory of Open Access Journals (Sweden)

    Marc R Van Gilst

    2005-02-01

    Full Text Available Mammalian nuclear hormone receptors (NHRs, such as liver X receptor, farnesoid X receptor, and peroxisome proliferator-activated receptors (PPARs, precisely control energy metabolism. Consequently, these receptors are important targets for the treatment of metabolic diseases, including diabetes and obesity. A thorough understanding of NHR fat regulatory networks has been limited, however, by a lack of genetically tractable experimental systems. Here we show that deletion of the Caenorhabditis elegans NHR gene nhr-49 yielded worms with elevated fat content and shortened life span. Employing a quantitative RT-PCR screen, we found that nhr-49 influenced the expression of 13 genes involved in energy metabolism. Indeed, nhr-49 served as a key regulator of fat usage, modulating pathways that control the consumption of fat and maintain a normal balance of fatty acid saturation. We found that the two phenotypes of the nhr-49 knockout were linked to distinct pathways and were separable: The high-fat phenotype was due to reduced expression of enzymes in fatty acid beta-oxidation, and the shortened adult life span resulted from impaired expression of a stearoyl-CoA desaturase. Despite its sequence relationship with the mammalian hepatocyte nuclear factor 4 receptor, the biological activities of nhr-49 were most similar to those of the mammalian PPARs, implying an evolutionarily conserved role for NHRs in modulating fat consumption and composition. Our findings in C. elegans provide novel insights into how NHR regulatory networks are coordinated to govern fat metabolism.

  10. Photoaffinity labelling of the rat liver nuclear thyroid hormone receptor with (/sup 125/I)triiodothyronine

    Energy Technology Data Exchange (ETDEWEB)

    David-Inouye, Y.; Somack, R.; Nordeen, S.K.; Apriletti, J.W.; Baxter, J.D.; Eberhardt, N.L.

    1982-11-01

    (/sup 125/I)Triiodothyronine (T3) was used as a photoreactive probe for the thyroid hormone nuclear receptor in photoaffinity labelling experiments. Autoradiograms of photolysis products electrophoresed on either one or two-dimensional gels showed that (/sup 125/I)T3 covalently, but nonspecifically, labelled many proteins in the partially purified receptor preparations used. However, one of these proteins with an estimated molecular weight of 47,000 and an isoelectric point of approximately 6.2 +/- 0.5 pH units appears to be the thyroid hormone receptor, since, in contrast to the other proteins, its photoinduced labelling was blocked by concentrations of T3 and thyroxine (T4) similar to those that inhibit binding of (/sup 125/I)T3 by the receptor in equilibrium binding assays. In addition, the isoelectric point of the photolabelled protein agrees with that determined in separate equilibrium isoelectric focusing studies. These results indicate that (/sup 125/)T3 can serve as a photoreactive probe for the thyroid hormone nuclear receptor, and they suggest that this receptor is a single polypeptide chain of molecular weight 47,000 with an isoelectric point of 6.2 +/- 0.5 pH units.

  11. Photoaffinity labelling of the rat liver nuclear thyroid hormone receptor with (/sup 125/I)triiodothyronine

    Energy Technology Data Exchange (ETDEWEB)

    David-Inouye, Y. (Univ. of California, San Francisco); Somack, R; Nordeen, S.K.; Apriletti, J.W.; Baxter, J.D.; Eberhardt, N.L.

    1982-11-01

    (/sup 125/I)Triiodothyronine (T/sub 3/) was used as a photoreactive probe for the thyroid hormone nuclear receptor in photoaffinity labelling experiments. Autoradiograms of photolysis products electrophoresed on either one or two-dimensional gels showed that (/sup 125/I)T/sub 3/ covalently, but nonspecifically, labelled many proteins in the partially purified receptor preparations used. However, one of these proteins with an estimated molecular weight of 47,000 and an isoelectric point of approximately 6.2 +/- 0.5 pH units appears to be the thyroid hormone receptor, since, in contrast to the other proteins, its photoinduced labelling was blocked by concentrations of T/sub 3/ and thyroxine (T/sub 4/) similar to those that inhibit binding of (/sup 125/I)T/sub 3/ by the receptor in equilibrium binding assays. In addition, the isoelectric point of the photolabelled protein agrees with that determined in separate equilibrium isoelectric focusing studies. These results indicate that (/sup 125/I)T/sub 3/ can serve as a photoreactive probe for the thyroid hormone nuclear receptor, and they suggest that this receptor is a single polypeptide chain of molecular weight 47,000 with an isoelectric point of 6.2 +/- 0.5 pH units.

  12. A simple test of muscle coactivation estimation using electromyography

    Directory of Open Access Journals (Sweden)

    U.F. Ervilha

    2012-10-01

    Full Text Available In numerous motor tasks, muscles around a joint act coactively to generate opposite torques. A variety of indexes based on electromyography signals have been presented in the literature to quantify muscle coactivation. However, it is not known how to estimate it reliably using such indexes. The goal of this study was to test the reliability of the estimation of muscle coactivation using electromyography. Isometric coactivation was obtained at various muscle activation levels. For this task, any coactivation measurement/index should present the maximal score (100% of coactivation. Two coactivation indexes were applied. In the first, the antagonistic muscle activity (the lower electromyographic signal between two muscles that generate opposite joint torques is divided by the mean between the agonistic and antagonistic muscle activations. In the second, the ratio between antagonistic and agonistic muscle activation is calculated. Moreover, we computed these indexes considering different electromyographic amplitude normalization procedures. It was found that the first algorithm, with all signals normalized by their respective maximal voluntary coactivation, generates the index closest to the true value (100%, reaching 92 ± 6%. In contrast, the coactivation index value was 82 ± 12% when the second algorithm was applied and the electromyographic signal was not normalized (P < 0.04. The new finding of the present study is that muscle coactivation is more reliably estimated if the EMG signals are normalized by their respective maximal voluntary contraction obtained during maximal coactivation prior to dividing the antagonistic muscle activity by the mean between the agonistic and antagonistic muscle activations.

  13. Resonance assignments, secondary structure and 15N relaxation data of the human transcriptional coactivator hMBF1 (57-148)

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Masaki; Ozaki, Jun; Ikegami, Takahisa [Nara Institute of Science and Technology, Graduate School of Biological Sciences (Japan); Kabe, Yasuaki; Goto, Masahide [National Institute of Genetics, Department of Developmental Genetics (Japan); Ueda, Hitoshi; Hirose, Susumu [Tokyo Institute of Technology, Faculty of Bioscience and Biotechnology (Japan); Handa, Hiroshi [National Institute of Genetics, Department of Developmental Genetics (Japan); Shirakawa, Masahiro [Nara Institute of Science and Technology, Graduate School of Biological Sciences (Japan)

    1999-08-15

    Multiprotein bridging factor 1 (MBF1) is a transcriptional coactivator that is thought to bridge between the TATA box-binding protein (TBP) and DNA binding regulatory factors, and is conserved from yeast to human. Human MBF1 (hMBF1) can bind to TBP and to the nuclear receptor Ad4BP, and is suggested to mediate Ad4BP-dependent transcriptional activation. Here we report the resonance assignments and secondary structure of hMBF1 (57-148) that contains both TBP binding and activator binding residues. {sup 15}N relaxation data were also obtained. As a result, hMBF1 (57-148) was shown to consist of flexible N-terminal residues and a C-terminal domain. The C-terminal domain contains four helices and a conserved C-terminal region.

  14. Nuclear angiotensin II type 2 (AT2) receptors are functionally linked to nitric oxide production.

    Science.gov (United States)

    Gwathmey, Tanya M; Shaltout, Hossam A; Pendergrass, Karl D; Pirro, Nancy T; Figueroa, Jorge P; Rose, James C; Diz, Debra I; Chappell, Mark C

    2009-06-01

    Expression of nuclear angiotensin II type 1 (AT(1)) receptors in rat kidney provides further support for the concept of an intracellular renin-angiotensin system. Thus we examined the cellular distribution of renal ANG II receptors in sheep to determine the existence and functional roles of intracellular ANG receptors in higher order species. Receptor binding was performed using the nonselective ANG II antagonist (125)I-[Sar(1),Thr(8)]-ANG II ((125)I-sarthran) with the AT(1) antagonist losartan (LOS) or the AT(2) antagonist PD123319 (PD) in isolated nuclei (NUC) and plasma membrane (PM) fractions obtained by differential centrifugation or density gradient separation. In both fetal and adult sheep kidney, PD competed for the majority of cortical NUC (> or =70%) and PM (> or =80%) sites while LOS competition predominated in medullary NUC (> or =75%) and PM (> or =70%). Immunodetection with an AT(2) antibody revealed a single approximately 42-kDa band in both NUC and PM extracts, suggesting a mature molecular form of the NUC receptor. Autoradiography for receptor subtypes localized AT(2) in the tubulointerstitium, AT(1) in the medulla and vasa recta, and both AT(1) and AT(2) in glomeruli. Loading of NUC with the fluorescent nitric oxide (NO) detector DAF showed increased NO production with ANG II (1 nM), which was abolished by PD and N-nitro-l-arginine methyl ester, but not LOS. Our studies demonstrate ANG II receptor subtypes are differentially expressed in ovine kidney, while nuclear AT(2) receptors are functionally linked to NO production. These findings provide further evidence of a functional intracellular renin-angiotensin system within the kidney, which may represent a therapeutic target for the regulation of blood pressure.

  15. Molecular mechanisms of action of the soy isoflavones includes activation of promiscuous nuclear receptors. A review.

    Science.gov (United States)

    Ricketts, Marie-Louise; Moore, David D; Banz, William J; Mezei, Orsolya; Shay, Neil F

    2005-06-01

    Consumption of soy has been demonstrated to reduce circulating cholesterol levels, most notably reducing low-density lipoprotein (LDL) cholesterol levels in hypercholesterolemic individuals. The component or components that might be responsible for this effect is still a matter of debate or controversy among many researchers. Candidate agents include an activity of soy protein itself, bioactive peptides produced during the digestive process, or the soy isoflavones. Although soy intake may provide other health benefits including preventative or remediative effects on cancer, osteoporosis and symptoms of menopause, this review will focus on isoflavones as agents affecting lipid metabolism. Isoflavones were first discovered as a bioactive agent disrupting estrogen action in female sheep, thereby earning the often-used term 'phytoestrogens'. Subsequent work confirmed the ability of isoflavones to bind to estrogen receptors. Along with the cholesterol-lowering effect of soy intake, research that is more recent has pointed to a beneficial antidiabetic effect of soy intake, perhaps mediated by soy isoflavones. The two common categories of antidiabetic drugs acting on nuclear receptors known as peroxisome proliferator activated receptors (PPARs) are the fibrates and glitazones. We and others have recently asked the research question 'do the soy isoflavones have activities as either "phytofibrates" or "phytoglitazones"?' Such an activity should be able to be confirmed both in vivo and in vitro. In both the in vivo and in vitro cases, this action has indeed been confirmed. Further work suggests a possible action of isoflavones similar to the nonestrogenic ligands that bind the estrogen-related receptors (ERRs). Recently, these receptors have been demonstrated to contribute to lipolytic processes. Finally, evaluation of receptor activation studies suggests that thyroid receptor activation may provide additional clues explaining the metabolic action of isoflavones. The recent

  16. Global Developmental Gene Programing Involves a Nuclear Form of Fibroblast Growth Factor Receptor-1 (FGFR1.

    Directory of Open Access Journals (Sweden)

    Christopher Terranova

    Full Text Available Genetic studies have placed the Fgfr1 gene at the top of major ontogenic pathways that enable gastrulation, tissue development and organogenesis. Using genome-wide sequencing and loss and gain of function experiments the present investigation reveals a mechanism that underlies global and direct gene regulation by the nuclear form of FGFR1, ensuring that pluripotent Embryonic Stem Cells differentiate into Neuronal Cells in response to Retinoic Acid. Nuclear FGFR1, both alone and with its partner nuclear receptors RXR and Nur77, targets thousands of active genes and controls the expression of pluripotency, homeobox, neuronal and mesodermal genes. Nuclear FGFR1 targets genes in developmental pathways represented by Wnt/β-catenin, CREB, BMP, the cell cycle and cancer-related TP53 pathway, neuroectodermal and mesodermal programing networks, axonal growth and synaptic plasticity pathways. Nuclear FGFR1 targets the consensus sequences of transcription factors known to engage CREB-binding protein, a common coregulator of transcription and established binding partner of nuclear FGFR1. This investigation reveals the role of nuclear FGFR1 as a global genomic programmer of cell, neural and muscle development.

  17. Global Developmental Gene Programing Involves a Nuclear Form of Fibroblast Growth Factor Receptor-1 (FGFR1).

    Science.gov (United States)

    Terranova, Christopher; Narla, Sridhar T; Lee, Yu-Wei; Bard, Jonathan; Parikh, Abhirath; Stachowiak, Ewa K; Tzanakakis, Emmanuel S; Buck, Michael J; Birkaya, Barbara; Stachowiak, Michal K

    2015-01-01

    Genetic studies have placed the Fgfr1 gene at the top of major ontogenic pathways that enable gastrulation, tissue development and organogenesis. Using genome-wide sequencing and loss and gain of function experiments the present investigation reveals a mechanism that underlies global and direct gene regulation by the nuclear form of FGFR1, ensuring that pluripotent Embryonic Stem Cells differentiate into Neuronal Cells in response to Retinoic Acid. Nuclear FGFR1, both alone and with its partner nuclear receptors RXR and Nur77, targets thousands of active genes and controls the expression of pluripotency, homeobox, neuronal and mesodermal genes. Nuclear FGFR1 targets genes in developmental pathways represented by Wnt/β-catenin, CREB, BMP, the cell cycle and cancer-related TP53 pathway, neuroectodermal and mesodermal programing networks, axonal growth and synaptic plasticity pathways. Nuclear FGFR1 targets the consensus sequences of transcription factors known to engage CREB-binding protein, a common coregulator of transcription and established binding partner of nuclear FGFR1. This investigation reveals the role of nuclear FGFR1 as a global genomic programmer of cell, neural and muscle development.

  18. The orphan nuclear receptor Rev-Erbalpha is a peroxisome proliferator-activated receptor (PPAR) gamma target gene and promotes PPARgamma-induced adipocyte differentiation

    DEFF Research Database (Denmark)

    Fontaine, Coralie; Dubois, Guillaume; Duguay, Yannick;

    2003-01-01

    Rev-Erbalpha (NR1D1) is an orphan nuclear receptor encoded on the opposite strand of the thyroid receptor alpha gene. Rev-Erbalpha mRNA is induced during adipocyte differentiation of 3T3-L1 cells, and its expression is abundant in rat adipose tissue. Peroxisome proliferator-activated receptor gamma...... (PPARgamma) (NR1C3) is a nuclear receptor controlling adipocyte differentiation and insulin sensitivity. Here we show that Rev-Erbalpha expression is induced by PPARgamma activation with rosiglitazone in rat epididymal and perirenal adipose tissues in vivo as well as in 3T3-L1 adipocytes in vitro...... for this nuclear receptor as a promoter of adipocyte differentiation....

  19. The NR4A nuclear receptors as potential targets for anti-aging interventions.

    Science.gov (United States)

    Paillasse, Michael R; de Medina, Philippe

    2015-02-01

    The development of innovative anti-aging strategy is urgently needed to promote healthy aging and overcome the occurrence of age-related diseases such as cancer, diabetes, cardiovascular and neurodegenerative diseases. Genomic instability, deregulated nutrient sensing and mitochondrial dysfunction are established hallmark of aging. Interestingly, the orphan nuclear receptors NR4A subfamily (NR4A1, NR4A2 and NR4A3) are nutrient sensors that trigger mitochondria biogenesis and improve intrinsic mitochondrial function. In addition, NR4A receptors are components of DNA repair machinery and promote DNA repair. Members of the NR4A subfamily should also be involved in anti-aging properties of hormesis since these receptors are induced by various form of cellular stress and stimulate protective cells response such as anti-oxidative activity and DNA repair. Previous studies reported that NR4A nuclear receptors subfamily is potential therapeutic targets for the treatment of age related disorders (e.g. metabolic syndromes, diabetes and neurodegenerative diseases). Consequently, we propose that targeting NR4A receptors might constitute a new approach to delay aging and the onset of diseases affecting our aging population.

  20. The putative roles of nuclear and membrane-bound progesterone receptors in the female reproductive tract.

    Science.gov (United States)

    Kowalik, Magdalena K; Rekawiecki, Robert; Kotwica, Jan

    2013-12-01

    Progesterone produced by the corpus luteum (CL) is a key regulator of normal cyclical reproductive functions in the females of mammalian species. The physiological effects of progesterone are mediated by the canonical genomic pathway after binding of progesterone to its specific nuclear progesterone receptor (PGR), which acts as a ligand-activated transcription factor and has two main isoforms, PGRA and PGRB. These PGR isoforms play different roles in the cell; PGRB acts as an activator of progesterone-responsive genes, while PGRA can inhibit the activity of PGRB. The ratio of these isoforms changes during the estrous cycle and pregnancy, and it corresponds to the different levels of progesterone signaling occurring in the reproductive tract. Progesterone exerts its effects on cells also by a non-genomic mechanism by the interaction with the progesterone-binding membrane proteins including the progesterone membrane component (PGRMC) 1 and 2, and the membrane progestin receptors (mPRs). These receptors rapidly activate the appropriate intracellular signal transduction pathways, and subsequently they can initiate specific cell responses or modulate genomic cell responses. The diversity of progesterone receptors and their cellular actions enhances the role of progesterone as a factor regulating the function of the reproductive system and other organs. This paper deals with the possible involvement of nuclear and membrane-bound progesterone receptors in the function of target cells within the female reproductive tract.

  1. Regulation of CYP3A4 by pregnane X receptor: The role of nuclear receptors competing for response element binding

    Energy Technology Data Exchange (ETDEWEB)

    Istrate, Monica A., E-mail: monicai@scripps.edu [Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany, and University of Tuebingen, Auerbachstr. 112, D-70376 Stuttgart (Germany); Nussler, Andreas K., E-mail: nuessler@uchir.me.tum.de [Department of Traumatology, Technical University Munich, Ismaningerstr. 22, 81675 Munich (Germany); Eichelbaum, Michel, E-mail: michel.eichelbaum@ikp-stuttgart.de [Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany, and University of Tuebingen, Auerbachstr. 112, D-70376 Stuttgart (Germany); Burk, Oliver, E-mail: oliver.burk@ikp-stuttgart.de [Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany, and University of Tuebingen, Auerbachstr. 112, D-70376 Stuttgart (Germany)

    2010-03-19

    Induction of the major drug metabolizing enzyme CYP3A4 by xenobiotics contributes to the pronounced interindividual variability of its expression and often results in clinically relevant drug-drug interactions. It is mainly mediated by PXR, which regulates CYP3A4 expression by binding to several specific elements in the 5' upstream regulatory region of the gene. Induction itself shows a marked interindividual variability, whose underlying determinants are only partly understood. In this study, we investigated the role of nuclear receptor binding to PXR response elements in CYP3A4, as a potential non-genetic mechanism contributing to interindividual variability of induction. By in vitro DNA binding experiments, we showed that several nuclear receptors bind efficiently to the proximal promoter ER6 and distal xenobiotic-responsive enhancer module DR3 motifs. TR{alpha}1, TR{beta}1, COUP-TFI, and COUP-TFII further demonstrated dose-dependent repression of PXR-mediated CYP3A4 enhancer/promoter reporter activity in transient transfection in the presence and absence of the PXR inducer rifampin, while VDR showed this effect only in the absence of treatment. By combining functional in vitro characterization with hepatic expression analysis, we predict that TR{alpha}1, TR{beta}1, COUP-TFI, and COUP-TFII show a strong potential for the repression of PXR-mediated activation of CYP3A4 in vivo. In summary, our results demonstrate that nuclear receptor binding to PXR response elements interferes with PXR-mediated expression and induction of CYP3A4 and thereby contributes to the interindividual variability of induction.

  2. Maintenance of Glucose Homeostasis Through Acetylation of the Metabolic Transcriptional Coactivator PGC1-alpha

    Science.gov (United States)

    2011-02-01

    examined using a fluo- rescence microscope (Carl Zeiss Axiovert 135) and IPLab software (Scana- lytics) was used to collect digital images. Animal...of hepatic gluconeogenesis through the transcriptional coactivator PGC-1. Nature 413, 131–138. Zilliacus, J., Holter , E., Wakui, H., Tazawa, H...analyzed by Affy- metrix MAS 5.0 software and GSEA (http://www.broad.mit.edu/gsea) (Mootha et al., 2003; Subramanian et al., 2005). Nuclear protein

  3. Clustering nuclear receptors in liver regeneration identifies candidate modulators of hepatocyte proliferation and hepatocarcinoma.

    Directory of Open Access Journals (Sweden)

    Michele Vacca

    Full Text Available BACKGROUND & AIMS: Liver regeneration (LR is a valuable model for studying mechanisms modulating hepatocyte proliferation. Nuclear receptors (NRs are key players in the control of cellular functions, being ideal modulators of hepatic proliferation and carcinogenesis. METHODS & RESULTS: We used a previously validated RT-qPCR platform to profile modifications in the expression of all 49 members of the NR superfamily in mouse liver during LR. Twenty-nine NR transcripts were significantly modified in their expression during LR, including fatty acid (peroxisome proliferator-activated receptors, PPARs and oxysterol (liver X receptors, Lxrs sensors, circadian masters RevErbα and RevErbβ, glucocorticoid receptor (Gr and constitutive androxane receptor (Car. In order to detect the NRs that better characterize proliferative status vs. proliferating liver, we used the novel Random Forest (RF analysis to selected a trio of down-regulated NRs (thyroid receptor alpha, Trα; farsenoid X receptor beta, Fxrβ; Pparδ as best discriminators of the proliferating status. To validate our approach, we further studied PPARδ role in modulating hepatic proliferation. We first confirmed the suppression of PPARδ both in LR and human hepatocellular carcinoma at protein level, and then demonstrated that PPARδ agonist GW501516 reduces the proliferative potential of hepatoma cells. CONCLUSIONS: Our data suggest that NR transcriptome is modulated in proliferating liver and is a source of biomarkers and bona fide pharmacological targets for the management of liver disease affecting hepatocyte proliferation.

  4. Role of nuclear progesterone receptor isoforms in uterine pathophysiology.

    Science.gov (United States)

    Patel, Bansari; Elguero, Sonia; Thakore, Suruchi; Dahoud, Wissam; Bedaiwy, Mohamed; Mesiano, Sam

    2015-01-01

    Progesterone is a key hormonal regulator of the female reproductive system. It plays a major role to prepare the uterus for implantation and in the establishment and maintenance of pregnancy. Actions of progesterone on the uterine tissues (endometrium, myometrium and cervix) are mediated by the combined effects of two progesterone receptor (PR) isoforms, designated PR-A and PR-B. Both receptors function primarily as ligand-activated transcription factors. Progesterone action on the uterine tissues is qualitatively and quantitatively determined by the relative levels and transcriptional activities of PR-A and PR-B. The transcriptional activity of the PR isoforms is affected by specific transcriptional coregulators and by PR post-translational modifications that affect gene promoter targeting. In this context, appropriate temporal and cell-specific expression and function of PR-A and PR-B are critical for normal uterine function. Relevant studies describing the role of PRs in uterine physiology and pathology (endometriosis, uterine leiomyoma, endometrial cancer, cervical cancer and recurrent pregnancy loss) were comprehensively searched using PubMed, Cochrane Library, Web of Science, and Google Scholar and critically reviewed. Progesterone, acting through PR-A and PR-B, regulates the development and function of the endometrium and induces changes in cells essential for implantation and the establishment and maintenance of pregnancy. During pregnancy, progesterone via the PRs promotes myometrial relaxation and cervical closure. Withdrawal of PR-mediated progesterone signaling triggers menstruation and parturition. PR-mediated progesterone signaling is anti-mitogenic in endometrial epithelial cells, and as such, mitigates the tropic effects of estrogen on eutopic normal endometrium, and on ectopic implants in endometriosis. Similarly, ligand-activated PRs function as tumor suppressors in endometrial cancer cells through inhibition of key cellular signaling pathways

  5. Altered activity profile of a tertiary silanol analog of multi-targeting nuclear receptor modulator T0901317.

    Science.gov (United States)

    Toyama, Hirozumi; Sato, Shoko; Shirakawa, Hitoshi; Komai, Michio; Hashimoto, Yuichi; Fujii, Shinya

    2016-04-01

    We report the design, synthesis, and physicochemical/biological evaluation of novel silanol derivative 6 (sila-T) as a silanol analog of multi-target nuclear receptor modulator T0901317 (5). Compound 6 showed intermediate hydrophobicity between the corresponding alcohol 13 and perfluoroalcohol 5. While 5 exhibited potent activities toward liver X receptor α and β, farnesoid X receptor, pregnane X receptor (PXR) and retinoic acid receptor-related orphan receptor (ROR)γ, silanol 6 exhibited activity only toward PXR and RORs. Incorporation of silanol instead of perfluoroalcohol is a promising option for developing novel target-selective, biologically active compounds.

  6. Coactivator SRC-2–dependent metabolic reprogramming mediates prostate cancer survival and metastasis

    OpenAIRE

    Dasgupta, Subhamoy; Putluri, Nagireddy; Long, Weiwen; Zhang, Bin; Wang, Jianghua; Kaushik, Akash K.; Arnold, James M.; Bhowmik, Salil K.; Stashi, Erin; Brennan, Christine A; Rajapakshe, Kimal; Coarfa, Cristian; Mitsiades, Nicholas; Ittmann, Michael M.; Chinnaiyan, Arul M

    2015-01-01

    Metabolic pathway reprogramming is a hallmark of cancer cell growth and survival and supports the anabolic and energetic demands of these rapidly dividing cells. The underlying regulators of the tumor metabolic program are not completely understood; however, these factors have potential as cancer therapy targets. Here, we determined that upregulation of the oncogenic transcriptional coregulator steroid receptor coactivator 2 (SRC-2), also known as NCOA2, drives glutamine-dependent de novo lip...

  7. Cannabinoids go nuclear: evidence for activation of peroxisome proliferator-activated receptors

    Science.gov (United States)

    O'Sullivan, S E

    2007-01-01

    Cannabinoids act at two classical cannabinoid receptors (CB1 and CB2), a 7TM orphan receptor and the transmitter-gated channel transient receptor potential vanilloid type-1 receptor. Recent evidence also points to cannabinoids acting at members of the nuclear receptor family, peroxisome proliferator-activated receptors (PPARs, with three subtypes α, β (δ) and γ), which regulate cell differentiation and lipid metabolism. Much evidence now suggests that endocannabinoids are natural activators of PPARα. Oleoylethanolamide regulates feeding and body weight, stimulates fat utilization and has neuroprotective effects mediated through activation of PPARα. Similarly, palmitoylethanolamide regulates feeding and lipid metabolism and has anti-inflammatory properties mediated by PPARα. Other endocannabinoids that activate PPARα include anandamide, virodhamine and noladin. Some (but not all) endocannabinoids also activate PPARγ; anandamide and 2-arachidonoylglycerol have anti-inflammatory properties mediated by PPARγ. Similarly, ajulemic acid, a structural analogue of a metabolite of Δ9-tetrahydrocannabinol (THC), causes anti-inflammatory effects in vivo through PPARγ. THC also activates PPARγ, leading to a time-dependent vasorelaxation in isolated arteries. Other cannabinoids which activate PPARγ include N-arachidonoyl-dopamine, HU210, WIN55212-2 and CP55940. In contrast, little research has been carried out on the effects of cannabinoids at PPARδ. In this newly emerging area, a number of research questions remain unanswered; for example, why do cannabinoids activate some isoforms and not others? How much of the chronic effects of cannabinoids are through activation of nuclear receptors? And importantly, do cannabinoids confer the same neuro- and cardioprotective benefits as other PPARα and PPARγ agonists? This review will summarize the published literature implicating cannabinoid-mediated PPAR effects and discuss the implications thereof. PMID:17704824

  8. Analysis of the heat shock response in mouse liver reveals dependence on the Nuclear Receptor Peroxisome Proliferator-Activated Receptor alpha (PPARalpha)

    NARCIS (Netherlands)

    Vallanat, B.; Anderson, S.P.; Brown-Borg, H.M.; Ren, H.; Kersten, A.H.; Jonnalagadda, S.; Srinivasan, S.; Corton, J.C.

    2010-01-01

    Background - The nuclear receptor peroxisome proliferator-activated receptor alpha (PPARa) regulates responses to chemical or physical stress in part by altering expression of genes involved in proteome maintenance. Many of these genes are also transcriptionally regulated by heat shock (HS) through

  9. Interactions Between IGFBP-3 and Nuclear Receptors in Prostate Cancer Apoptosis

    Science.gov (United States)

    2010-01-01

    and cytoplasmic export. We have previously described nucleo -mitochondrial translocation of nuclear receptor RXRα/Nur77 heterodimers to activate the...nloaded from mediating anti-prolific actions, recombinant IGFBP-3 was used to inhibit basal and estradiol-stimulated cell proliferation, and IGFBP-3...treatment in ECE16–1 cells (human papillomavirus-immortalized cervical epithelial cells) (7). Also, addition of mitogenic EGF to basal human keratin

  10. Cold exposure rapidly induces virtual saturation of brown adipose tissue nuclear T sub 3 receptors

    Energy Technology Data Exchange (ETDEWEB)

    Bianco, A.C.; Silva, J.E. (Univ. of Sao Paulo (Brazil) Harvard Medical School, Boston, MA (USA))

    1988-10-01

    Cold exposure induces a rapid increase in uncoupling protein (UCP) concentration in the brown adipose tissue (BAT) of euthyroid, but not hypothyroid, rats. To normalize this response with exogenous 3,5,3{prime}-triiodothyronine (T{sub 3}), it is necessary to cause systemic hyperthyroidism. In contrast, the same result can be obtained with just replacement doses of thyroxine (T{sub 4}) and, in euthyroid rats, the normal response of UCP to cold occurs without hyperthyroid plasma T{sub 3} levels. Consequently, the authors explored the possibility that the cold-induced activation of the type II 5{prime}-deiodinase resulted in high levels of nuclear T{sub 3} receptor occupancy in euthyroid rats. Studies were performed with pulse injections of tracer T{sub 3} or T{sub 4} in rats exposed to 4{degree}C for different lengths of time (1 h-3 wk). Within 4 h of cold exposure, they observed a significant increase in the nuclear ({sup 125}I)T{sub 3} derived from the tracer ({sup 125}I)T{sub 4} injections (T{sub 3}(T{sub 4})) and a significant reduction in the nuclear ({sup 125}I)T{sub 3} derived from ({sup 125}I)T{sub 3} injections (T{sub 3}(T{sub 3})). The number of BAT nuclear T{sub 3} receptors did not increase for up to 3 wk of observation at 4{degree}C. The mass of nuclear-bound T{sub 3} was calculated from the nuclear tracer ({sup 125}I)T{sub 3}(T{sub 3}) and ({sup 125}I)T{sub 3}(T{sub 4}) at equilibrium and the specific activity of serum T{sub 3} and T{sub 4}, respectively. By 4 h after the initiation of the cold exposure, the receptors were >95% occupied and remained so for the 3 weeks of observation. They conclude that the simultaneous activation of the deiodinase with adrenergic BAT stimulation serves the purpose of nearly saturating the nuclear T{sub 3} receptors. This makes possible the realization of the full thermogenic potential of the tissue without causing systemic hyperthyroidism.

  11. A Cistanches Herba Fraction/β-Sitosterol Causes a Redox-Sensitive Induction of Mitochondrial Uncoupling and Activation of Adenosine Monophosphate-Dependent Protein Kinase/Peroxisome Proliferator-Activated Receptor γ Coactivator-1 in C2C12 Myotubes: A Possible Mechanism Underlying the Weight Reduction Effect

    Directory of Open Access Journals (Sweden)

    Hoi Shan Wong

    2015-01-01

    Full Text Available Previous studies have demonstrated that HCF1, a semipurified fraction of Cistanches Herba, causes weight reduction in normal diet- and high fat diet-fed mice. The weight reduction was associated with the induction of mitochondrial uncoupling and changes in metabolic enzyme activities in mouse skeletal muscle. To further investigate the biochemical mechanism underlying the HCF1-induced weight reduction, the effect of HCF1 and its active component, β-sitosterol (BSS, on C2C12 myotubes was examined. Incubation with HCF1/BSS caused a transient increase in mitochondrial membrane potential (MMP, possibly by fluidizing the mitochondrial inner membrane. The increase in MMP was paralleled to an increase in mitochondrial reactive oxygen species (ROS production. Mitochondrial ROS, in turn, triggered a redox-sensitive induction of mitochondrial uncoupling by uncoupling protein 3 (UCP3. Biochemical analysis indicated that HCF1 was capable of activating an adenosine monophosphate-dependent protein kinase/peroxisome proliferator-activated receptor γ coactivator-1 pathway and thereby increased the expression of cytochrome c oxidase and UCP3. Animal studies using mitochondrial recoupler also confirmed the role of mitochondrial uncoupling in the HCF1-induced weight reduction. In conclusion, a HCF1/BSS causes the redox-sensitive induction of mitochondrial uncoupling and activation of AMPK/PGC-1 in C2C12 myotubes, with resultant reductions in body weight and adiposity by increased energy consumption.

  12. Germ cell nuclear factor directly represses the transcription of peroxisome proliferator-activated receptor delta gene

    Institute of Scientific and Technical Information of China (English)

    Chengqiang He; Naizheng Ding; Jie Kang

    2008-01-01

    Germ cell nuclear factor (GCNF) is a transcription factor that can repress gene transcription and plays an important role during spermatogenesis. Peroxisome proliferator-activated receptor delta (PPARδ) is a nuclear hormone receptor belonging to the steroid receptor superfamily.It can activate the expression of many genes,including those involved in lipid metabolism.In this report,we showed that GCNF specifically interacts with PPARδ promoter.Overexpression of GCNF in African green monkey SV40 transformed kidney fibroblast COS7 cells and mouse embryo fibroblast NIH 3T3 cells represses the activity of PPARδ promoter.The mutation of GCNF response element in PPARδ promoter relieves the repression in NIH 3T3 cells and mouse testis.Moreover,we showed that GCNF in nuclear extracts of mouse testis is able to bind to PPARδ promoter directly.We also found that GCNF and PPARδ mRNA were expressed with different patterns in mouse testis by in situ hybridization.These results suggested that GCNF might be a negative regulator of PPARδ gene expression through its direct interaction with PPARδ promoter in mouse testis.

  13. The antidepressant fluoxetine normalizes the nuclear glucocorticoid receptor evoked by psychosocial stress

    Science.gov (United States)

    Mitić, M.; Simić, I.; Djordjević, J.; Radojčić, M. B.; Adžić, M.

    2011-12-01

    Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the pathophysiology of depression and stress disorders. Glucocorticoids, key regulators of the stress response, exert diverse effects on cellular processes in the hippocampus. Beside non-genomic pathways, glucocorticoid effects are mediated through activation of the glucocorticoid receptor (GR), a ligand activated transcriptional factor that belongs to the nuclear hormone receptor superfamily. We analysed the GR protein levels both in the cytoplasmic and nuclear compartments of the hippocampus of Wistar rats exposed to chronic psychosocial isolation stress upon chronic fluoxetine (FLU) treatment. Under chronic stress, corticosterone levels (CORT) were decreased compared to the control, and treatment with FLU did not change its level in the stressed rats. At the molecular level, FLU normalized the level of nuclear GR protein in the hippocampus of the stressed rats. Discrepancy between normalization of nuclear GR in the hippocampus and lack of normalization of HPA axis activity judged by CORT, suggests that other brain structures such as the amygdale and prefrontal cortex that also regulate HPA axis activity, seem not to be normalized by the FLU treatment used in our study.

  14. Plasma membrane and nuclear localization of G protein coupled receptor kinase 6A.

    Science.gov (United States)

    Jiang, Xiaoshan; Benovic, Jeffrey L; Wedegaertner, Philip B

    2007-08-01

    G protein-coupled receptor (GPCR) kinases (GRKs) specifically phosphorylate agonist-occupied GPCRs at the inner surface of the plasma membrane (PM), leading to receptor desensitization. Here we show that the C-terminal 30 amino acids of GRK6A contain multiple elements that either promote or inhibit PM localization. Disruption of palmitoylation by individual mutation of cysteine 561, 562, or 565 or treatment of cells with 2-bromopalmitate shifts GRK6A from the PM to both the cytoplasm and nucleus. Likewise, disruption of the hydrophobic nature of a predicted amphipathic helix by mutation of two leucines to alanines at positions 551 and 552 causes a loss of PM localization. Moreover, acidic amino acids in the C-terminus appear to negatively regulate PM localization; mutational replacement of several acidic residues with neutral or basic residues rescues PM localization of a palmitoylation-defective GRK6A. Last, we characterize the novel nuclear localization, showing that nuclear export of nonpalmitoylated GRK6A is sensitive to leptomycin B and that GRK6A contains a potential nuclear localization signal. Our results suggest that the C-terminus of GRK6A contains a novel electrostatic palmitoyl switch in which acidic residues weaken the membrane-binding strength of the amphipathic helix, thus allowing changes in palmitoylation to regulate PM versus cytoplasmic/nuclear localization.

  15. Plasma Membrane and Nuclear Localization of G Protein–coupled Receptor Kinase 6A

    Science.gov (United States)

    Jiang, Xiaoshan; Benovic, Jeffrey L.

    2007-01-01

    G protein–coupled receptor (GPCR) kinases (GRKs) specifically phosphorylate agonist-occupied GPCRs at the inner surface of the plasma membrane (PM), leading to receptor desensitization. Here we show that the C-terminal 30 amino acids of GRK6A contain multiple elements that either promote or inhibit PM localization. Disruption of palmitoylation by individual mutation of cysteine 561, 562, or 565 or treatment of cells with 2-bromopalmitate shifts GRK6A from the PM to both the cytoplasm and nucleus. Likewise, disruption of the hydrophobic nature of a predicted amphipathic helix by mutation of two leucines to alanines at positions 551 and 552 causes a loss of PM localization. Moreover, acidic amino acids in the C-terminus appear to negatively regulate PM localization; mutational replacement of several acidic residues with neutral or basic residues rescues PM localization of a palmitoylation-defective GRK6A. Last, we characterize the novel nuclear localization, showing that nuclear export of nonpalmitoylated GRK6A is sensitive to leptomycin B and that GRK6A contains a potential nuclear localization signal. Our results suggest that the C-terminus of GRK6A contains a novel electrostatic palmitoyl switch in which acidic residues weaken the membrane-binding strength of the amphipathic helix, thus allowing changes in palmitoylation to regulate PM versus cytoplasmic/nuclear localization. PMID:17538017

  16. Functional interactions of the AF-2 activation domain core region of the human androgen receptor with the amino-terminal domain and with the transcriptional coactivator TIF2 (transcriptional intermediary factor2)

    NARCIS (Netherlands)

    C.A. Berrevoets (Cor); P. Doesburg (Paul); K. Steketee (Karine); J. Trapman (Jan); A.O. Brinkmann (Albert)

    1998-01-01

    textabstractPrevious studies in yeast and mammalian cells showed a functional interaction between the amino-terminal domain and the carboxy-terminal, ligand-binding domain (LBD) of the human androgen receptor (AR). In the present study, the AR subdomains involved in thi

  17. Nuclear localization of the type 1 PTH/PTHrP receptor in rat tissues.

    Science.gov (United States)

    Watson, P H; Fraher, L J; Hendy, G N; Chung, U I; Kisiel, M; Natale, B V; Hodsman, A B

    2000-06-01

    The localization of PTH/PTH-related peptide (PTHrP) receptor (PTHR) has traditionally been performed by autoradiography. Specific polyclonal antibodies to peptides unique to the PTHR are now available, which allow a more precise localization of the receptor in cells and tissues. We optimized the IHC procedure for the rat PTHR using 5-microm sections of paraffin-embedded rat kidney, liver, small intestine, uterus, and ovary. Adjacent sections were analyzed for the presence of PTHR mRNA (by in situ hybridization) and PTHrP peptide. A typical pattern of staining for both receptor protein and mRNA was observed in kidney in cells lining the proximal tubules and collecting ducts. In uterus and gut, the receptor and its mRNA are present in smooth muscle layers (PTHrP target) and in glandular cuboidal cells and surface columnar epithelium. This suggests that PTH, or more likely PTHrP, plays a role in surface/secretory epithelia that is as yet undefined. In the ovary, PTHR was readily detectable in the thecal layer of large antral follicles and oocytes, and was present in the cytoplasm and/or nucleus of granulosa cells, regions that also contained receptor transcripts. PTHR protein and mRNA were found in the liver in large hepatocytes radiating outward from central veins. Immunoreactive cells were also present around the periphery of the liver but not within two or three cell layers of the surface. Clear nuclear localization of the receptor protein was present in liver cells in addition to the expected cytoplasmic/peripheral staining. PTHR immunoreactivity was present in the nucleus of some cells in every tissue examined. RT-PCR confirmed the presence of PTHR transcripts in these same tissues. Examination of the hindlimbs of PTHR gene-ablated mice showed no reaction to this antibody, whereas hindlimbs from their wild-type littermates stained positively. The results emphasize that the PTHR is highly expressed in diverse tissues and, in addition, show that the receptor

  18. Improved docking, screening and selectivity prediction for small molecule nuclear receptor modulators using conformational ensembles.

    Science.gov (United States)

    Park, So-Jung; Kufareva, Irina; Abagyan, Ruben

    2010-05-01

    Nuclear receptors (NRs) are ligand dependent transcriptional factors and play a key role in reproduction, development, and homeostasis of organism. NRs are potential targets for treatment of cancer and other diseases such as inflammatory diseases, and diabetes. In this study, we present a comprehensive library of pocket conformational ensembles of thirteen human nuclear receptors (NRs), and test the ability of these ensembles to recognize their ligands in virtual screening, as well as predict their binding geometry, functional type, and relative binding affinity. 157 known NR modulators and 66 structures were used as a benchmark. Our pocket ensemble library correctly predicted the ligand binding poses in 94% of the cases. The models were also highly selective for the active ligands in virtual screening, with the areas under the ROC curves ranging from 82 to a remarkable 99%. Using the computationally determined receptor-specific binding energy offsets, we showed that the ensembles can be used for predicting selectivity profiles of NR ligands. Our results evaluate and demonstrate the advantages of using receptor ensembles for compound docking, screening, and profiling.

  19. The Nuclear Hormone Receptor PPARγ as a Therapeutic Target in Major Diseases

    Directory of Open Access Journals (Sweden)

    Martina Victoria Schmidt

    2010-01-01

    Full Text Available The peroxisome proliferator-activated receptor γ (PPARγ belongs to the nuclear hormone receptor superfamily and regulates gene expression upon heterodimerization with the retinoid X receptor by ligating to peroxisome proliferator response elements (PPREs in the promoter region of target genes. Originally, PPARγ was identified as being essential for glucose metabolism. Thus, synthetic PPARγ agonists, the thiazolidinediones (TZDs, are used in type 2 diabetes therapy as insulin sensitizers. More recent evidence implied an important role for the nuclear hormone receptor PPARγ in controlling various diseases based on its anti-inflammatory, cell cycle arresting, and proapoptotic properties. In this regard, expression of PPARγ is not restricted to adipocytes, but is also found in immune cells, such as B and T lymphocytes, monocytes, macrophages, dendritic cells, and granulocytes. The expression of PPARγ in lymphoid organs and its modulation of macrophage inflammatory responses, lymphocyte proliferation, cytokine production, and apoptosis underscore its immune regulating functions. Moreover, PPARγ expression is found in tumor cells, where its activation facilitates antitumorigenic actions. This review provides an overview about the role of PPARγ as a possible therapeutic target approaching major, severe diseases, such as sepsis, cancer, and atherosclerosis.

  20. Nutrient-sensing nuclear receptors PPARα and FXR control liver energy balance.

    Science.gov (United States)

    Preidis, Geoffrey A; Kim, Kang Ho; Moore, David D

    2017-04-03

    The nuclear receptors PPARα (encoded by NR1C1) and farnesoid X receptor (FXR, encoded by NR1H4) are activated in the liver in the fasted and fed state, respectively. PPARα activation induces fatty acid oxidation, while FXR controls bile acid homeostasis, but both nuclear receptors also regulate numerous other metabolic pathways relevant to liver energy balance. Here we review evidence that they function coordinately to control key nutrient pathways, including fatty acid oxidation and gluconeogenesis in the fasted state and lipogenesis and glycolysis in the fed state. We have also recently reported that these receptors have mutually antagonistic impacts on autophagy, which is induced by PPARα but suppressed by FXR. Secretion of multiple blood proteins is a major drain on liver energy and nutrient resources, and we present preliminary evidence that the liver secretome may be directly suppressed by PPARα, but induced by FXR. Finally, previous studies demonstrated a striking deficiency in bile acid levels in malnourished mice that is consistent with results in malnourished children. We present evidence that hepatic targets of PPARα and FXR are dysregulated in chronic undernutrition. We conclude that PPARα and FXR function coordinately to integrate liver energy balance.

  1. Effects of different ligands on epidermal growth factor receptor (EGFR) nuclear translocation

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Jerusa A.Q.A.; Andrade, Carolina de; Goes, Alfredo M. [Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte, MG, 31270-901 (Brazil); Rodrigues, Michele A. [Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte, MG, 31270-901 (Brazil); Department of General Pathology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte, MG, 31270-901 (Brazil); Gomes, Dawidson A., E-mail: dawidson@ufmg.br [Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte, MG, 31270-901 (Brazil)

    2016-09-09

    The epidermal growth factor receptor (EGFR) is activated through binding to specific ligands and generates signals for proliferation, differentiation, migration, and cell survival. Recent data show the role of nuclear EGFR in tumors. Although many EGFR ligands are upregulated in cancers, little is known about their effects on EGFR nuclear translocation. We have compared the effects of six EGFR ligands (EGF, HB-EGF, TGF-α, β-Cellulin, amphiregulin, and epiregulin) on nuclear translocation of EGFR, receptor phosphorylation, migration, and proliferation. Cell fractionation and confocal immunofluorescence detected EGFR in the nucleus after EGF, HB-EGF, TGF-α and β-Cellulin stimulation in a dose-dependent manner. In contrast, amphiregulin and epiregulin did not generate nuclear translocation of EGFR. EGF, HB-EGF, TGF-α and β-Cellulin showed correlations between a higher rate of wound closure and increased phosphorylation of residues in the carboxy-terminus of EGFR, compared to amphiregulin and epiregulin. The data indicate that EGFR is translocated to the nucleus after stimulation with EGF, HB-EGF, TGF-α and β-Cellulin, and that these ligands are related to increased phosphorylation of EGFR tyrosine residues, inducing migration of SkHep-1 cells. - Highlights: • EGF, HB-EGF, TGF-α, β-Cellulin are involved in the EGFR nuclear translocation. • Amphiregulin and epiregulin did not promote nuclear translocation of EGFR. • EGF, HB-EGF, TGF-α and β-Cellulin have a role in SkHep-1 cells migration. • EGFR ligands associated with better prognosis don't stimulate EGFR translocation.

  2. Inflammatory Mediators and Insulin Resistance in Obesity: Role of Nuclear Receptor Signaling in Macrophages

    Directory of Open Access Journals (Sweden)

    Lucía Fuentes

    2010-01-01

    Full Text Available Visceral obesity is coupled to a general low-grade chronic inflammatory state characterized by macrophage activation and inflammatory cytokine production, leading to insulin resistance (IR. The balance between proinflammatory M1 and antiinflammatory M2 macrophage phenotypes within visceral adipose tissue appears to be crucially involved in the development of obesity-associated IR and consequent metabolic abnormalities. The ligand-dependent transcription factors peroxisome proliferator activated receptors (PPARs have recently been implicated in the determination of the M1/M2 phenotype. Liver X receptors (LXRs, which form another subgroup of the nuclear receptor superfamily, are also important regulators of proinflammatory cytokine production in macrophages. Disregulation of macrophage-mediated inflammation by PPARs and LXRs therefore underlies the development of IR. This review summarizes the role of PPAR and LXR signaling in macrophages and current knowledge about the impact of these actions in the manifestation of IR and obesity comorbidities such as liver steatosis and diabetic osteopenia.

  3. Orphan nuclear receptor oestrogen-related receptor γ (ERRγ) plays a key role in hepatic cannabinoid receptor type 1-mediated induction of CYP7A1 gene expression.

    Science.gov (United States)

    Zhang, Yaochen; Kim, Don-Kyu; Lee, Ji-Min; Park, Seung Bum; Jeong, Won-Il; Kim, Seong Heon; Lee, In-Kyu; Lee, Chul-Ho; Chiang, John Y L; Choi, Hueng-Sik

    2015-09-01

    Bile acids are primarily synthesized from cholesterol in the liver and have important roles in dietary lipid absorption and cholesterol homoeostasis. Detailed roles of the orphan nuclear receptors regulating cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme in bile acid synthesis, have not yet been fully elucidated. In the present study, we report that oestrogen-related receptor γ (ERRγ) is a novel transcriptional regulator of CYP7A1 expression. Activation of cannabinoid receptor type 1 (CB1 receptor) signalling induced ERRγ-mediated transcription of the CYP7A1 gene. Overexpression of ERRγ increased CYP7A1 expression in vitro and in vivo, whereas knockdown of ERRγ attenuated CYP7A1 expression. Deletion analysis of the CYP7A1 gene promoter and a ChIP assay revealed an ERRγ-binding site on the CYP7A1 gene promoter. Small heterodimer partner (SHP) inhibited the transcriptional activity of ERRγ and thus regulated CYP7A1 expression. Overexpression of ERRγ led to increased bile acid levels, whereas an inverse agonist of ERRγ, GSK5182, reduced CYP7A1 expression and bile acid synthesis. Finally, GSK5182 significantly reduced hepatic CB1 receptor-mediated induction of CYP7A1 expression and bile acid synthesis in alcohol-treated mice. These results provide the molecular mechanism linking ERRγ and bile acid metabolism.

  4. The export receptor Crm1 forms a dimer to promote nuclear export of HIV RNA.

    Science.gov (United States)

    Booth, David S; Cheng, Yifan; Frankel, Alan D

    2014-12-08

    The HIV Rev protein routes viral RNAs containing the Rev Response Element (RRE) through the Crm1 nuclear export pathway to the cytoplasm where viral proteins are expressed and genomic RNA is delivered to assembling virions. The RRE assembles a Rev oligomer that displays nuclear export sequences (NESs) for recognition by the Crm1-Ran(GTP) nuclear receptor complex. Here we provide the first view of an assembled HIV-host nuclear export complex using single-particle electron microscopy. Unexpectedly, Crm1 forms a dimer with an extensive interface that enhances association with Rev-RRE and poises NES binding sites to interact with a Rev oligomer. The interface between Crm1 monomers explains differences between Crm1 orthologs that alter nuclear export and determine cellular tropism for viral replication. The arrangement of the export complex identifies a novel binding surface to possibly target an HIV inhibitor and may point to a broader role for Crm1 dimerization in regulating host gene expression.

  5. Widespread nuclear and cytoplasmic accumulation of mutant androgen receptor in SBMA patients.

    Science.gov (United States)

    Adachi, Hiroaki; Katsuno, Masahisa; Minamiyama, Makoto; Waza, Masahiro; Sang, Chen; Nakagomi, Yuji; Kobayashi, Yasushi; Tanaka, Fumiaki; Doyu, Manabu; Inukai, Akira; Yoshida, Mari; Hashizume, Yoshio; Sobue, Gen

    2005-03-01

    Spinal and bulbar muscular atrophy (SBMA) is an inherited adult onset motor neuron disease caused by the expansion of a polyglutamine (polyQ) tract within the androgen receptor (AR), affecting only males. The characteristic pathological finding is nuclear inclusions (NIs) consisting of mutant AR with an expanded polyQ in residual motor neurons, and in certain visceral organs. We immunohistochemically examined 11 SBMA patients at autopsy with 1C2, an antibody that specifically recognizes expanded polyQ. Our study demonstrated that diffuse nuclear accumulation of mutant AR was far more frequent and extensive than NIs being distributed in a wide array of CNS nuclei, and in more visceral organs than thus far believed. Mutant AR accumulation was also present in the cytoplasm, particularly in the Golgi apparatus; nuclear or cytoplasmic predominance of accumulation was tissue specific. Furthermore, the extent of diffuse nuclear accumulation of mutant AR in motor and sensory neurons of the spinal cord was closely related to CAG repeat length. Thus, diffuse nuclear accumulation of mutant AR apparently is a cardinal pathogenetic process underlying neurological manifestations, as in SBMA transgenic mice, while cytoplasmic accumulation may also contribute to SBMA pathophysiology.

  6. Fatty Acid Amide Hydrolase (FAAH) Inhibition Enhances Memory Acquisition through Activation of PPAR-alpha Nuclear Receptors

    Science.gov (United States)

    Mazzola, Carmen; Medalie, Julie; Scherma, Maria; Panlilio, Leigh V.; Solinas, Marcello; Tanda, Gianluigi; Drago, Filippo; Cadet, Jean Lud; Goldberg, Steven R.; Yasar, Sevil

    2009-01-01

    Inhibitors of fatty acid amide hydrolase (FAAH) increase endogenous levels of anandamide (a cannabinoid CB[subscript 1]-receptor ligand) and oleoylethanolamide and palmitoylethanolamide (OEA and PEA, ligands for alpha-type peroxisome proliferator-activated nuclear receptors, PPAR-alpha) when and where they are naturally released in the brain.…

  7. Fatty Acid Amide Hydrolase (FAAH) Inhibition Enhances Memory Acquisition through Activation of PPAR-alpha Nuclear Receptors

    Science.gov (United States)

    Mazzola, Carmen; Medalie, Julie; Scherma, Maria; Panlilio, Leigh V.; Solinas, Marcello; Tanda, Gianluigi; Drago, Filippo; Cadet, Jean Lud; Goldberg, Steven R.; Yasar, Sevil

    2009-01-01

    Inhibitors of fatty acid amide hydrolase (FAAH) increase endogenous levels of anandamide (a cannabinoid CB[subscript 1]-receptor ligand) and oleoylethanolamide and palmitoylethanolamide (OEA and PEA, ligands for alpha-type peroxisome proliferator-activated nuclear receptors, PPAR-alpha) when and where they are naturally released in the brain.…

  8. Nuclear receptor 4A (NR4A) family - orphans no more.

    Science.gov (United States)

    Safe, Stephen; Jin, Un-Ho; Morpurgo, Benjamin; Abudayyeh, Ala; Singh, Mandip; Tjalkens, Ronald B

    2016-03-01

    The orphan nuclear receptors NR4A1, NR4A2 and NR4A3 are immediate early genes induced by multiple stressors, and the NR4A receptors play an important role in maintaining cellular homeostasis and disease. There is increasing evidence for the role of these receptors in metabolic, cardiovascular and neurological functions and also in inflammation and inflammatory diseases and in immune functions and cancer. Despite the similarities of NR4A1, NR4A2 and NR4A3 and their interactions with common cis-genomic elements, they exhibit unique activities and cell-/tissue-specific functions. Although endogenous ligands for NR4A receptors have not been identified, there is increasing evidence that structurally-diverse synthetic molecules can directly interact with the ligand binding domain of NR4A1 and act as agonists or antagonists, and ligands for NR4A2 and NR4A3 have also been identified. Since NR4A receptors are key factors in multiple diseases, there are opportunities for the future development of NR4A ligands for clinical applications in treating multiple health problems including metabolic, neurologic and cardiovascular diseases, other inflammatory conditions, and cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. GSK3beta is a negative regulator of the transcriptional coactivator MAML1.

    Science.gov (United States)

    Saint Just Ribeiro, Mariana; Hansson, Magnus L; Lindberg, Mikael J; Popko-Scibor, Anita E; Wallberg, Annika E

    2009-11-01

    Glycogen synthase kinase 3beta (GSK3beta) is involved in several cellular signaling systems through regulation of the activity of diverse transcription factors such as Notch, p53 and beta-catenin. Mastermind-like 1 (MAML1) was originally identified as a Notch coactivator, but has also been reported to function as a transcriptional coregulator of p53, beta-catenin and MEF2C. In this report, we show that active GSK3beta directly interacts with the MAML1 N-terminus and decreases MAML1 transcriptional activity, suggesting that GSK3beta might target a coactivator in its regulation of gene expression. We have previously shown that MAML1 increases global acetylation of histones, and here we show that the GSK3 inhibitor SB41, further enhances MAML1-dependent histone acetylation in cells. Finally, MAML1 translocates GSK3beta to nuclear bodies; this function requires full-length MAML1 protein.

  10. Nuclear functions and subcellular trafficking mechanisms of the epidermal growth factor receptor family

    Science.gov (United States)

    2012-01-01

    Accumulating evidence suggests that various diseases, including many types of cancer, result from alteration of subcellular protein localization and compartmentalization. Therefore, it is worthwhile to expand our knowledge in subcellular trafficking of proteins, such as epidermal growth factor receptor (EGFR) and ErbB-2 of the receptor tyrosine kinases, which are highly expressed and activated in human malignancies and frequently correlated with poor prognosis. The well-characterized trafficking of cell surface EGFR is routed, via endocytosis and endosomal sorting, to either the lysosomes for degradation or back to the plasma membrane for recycling. A novel nuclear mode of EGFR signaling pathway has been gradually deciphered in which EGFR is shuttled from the cell surface to the nucleus after endocytosis, and there, it acts as a transcriptional regulator, transmits signals, and is involved in multiple biological functions, including cell proliferation, tumor progression, DNA repair and replication, and chemo- and radio-resistance. Internalized EGFR can also be transported from the cell surface to several intracellular compartments, such as the Golgi apparatus, the endoplasmic reticulum, and the mitochondria, in addition to the nucleus. In this review, we will summarize the functions of nuclear EGFR family and the potential pathways by which EGFR is trafficked from the cell surface to a variety of cellular organelles. A better understanding of the molecular mechanism of EGFR trafficking will shed light on both the receptor biology and potential therapeutic targets of anti-EGFR therapies for clinical application. PMID:22520625

  11. Regulation of miR-200c by Nuclear Receptors PPARα, LRH-1 and SHP

    Science.gov (United States)

    Zhang, Yuxia; Yang, Zhihong; Whitby, Richard; Wang, Li

    2011-01-01

    We investigated regulation of miR-200c expression by nuclear receptors. Ectopic expression of miR-200c inhibited MHCC97H cell migration, which was abrogated by the synergistic effects of PPARα and LRH-1 siRNAs. The expression of miR-200c was decreased by PPARα/LRH-1 siRNAs and increased by SHP siRNAs, and overexpression of the receptors reversed the effects of their respective siRNAs. SHP siRNAs also drastically enhanced the ability of the LRH-1 agonist RJW100 to induce miR-200c and downregulate ZEB1 and ZEB2 proteins. Co-expression of PPARα and LRH-1 moderately transactivated the miR-200c promoter, which was repressed by SHP co-expression. RJW100 caused strong activation of the miR-200c promoter. This is the first report to demonstrate that miR-200c expression is controlled by nuclear receptors. PMID:22100809

  12. Nuclear functions and subcellular trafficking mechanisms of the epidermal growth factor receptor family

    Directory of Open Access Journals (Sweden)

    Wang Ying-Nai

    2012-04-01

    Full Text Available Abstract Accumulating evidence suggests that various diseases, including many types of cancer, result from alteration of subcellular protein localization and compartmentalization. Therefore, it is worthwhile to expand our knowledge in subcellular trafficking of proteins, such as epidermal growth factor receptor (EGFR and ErbB-2 of the receptor tyrosine kinases, which are highly expressed and activated in human malignancies and frequently correlated with poor prognosis. The well-characterized trafficking of cell surface EGFR is routed, via endocytosis and endosomal sorting, to either the lysosomes for degradation or back to the plasma membrane for recycling. A novel nuclear mode of EGFR signaling pathway has been gradually deciphered in which EGFR is shuttled from the cell surface to the nucleus after endocytosis, and there, it acts as a transcriptional regulator, transmits signals, and is involved in multiple biological functions, including cell proliferation, tumor progression, DNA repair and replication, and chemo- and radio-resistance. Internalized EGFR can also be transported from the cell surface to several intracellular compartments, such as the Golgi apparatus, the endoplasmic reticulum, and the mitochondria, in addition to the nucleus. In this review, we will summarize the functions of nuclear EGFR family and the potential pathways by which EGFR is trafficked from the cell surface to a variety of cellular organelles. A better understanding of the molecular mechanism of EGFR trafficking will shed light on both the receptor biology and potential therapeutic targets of anti-EGFR therapies for clinical application.

  13. Human transcriptional coactivator with PDZ-binding motif (TAZ) is downregulated during decidualization.

    Science.gov (United States)

    Strakova, Zuzana; Reed, Jennifer; Ihnatovych, Ivanna

    2010-06-01

    Transcriptional coactivator with PDZ-binding motif (TAZ) is known to bind to a variety of transcription factors to control cell differentiation and organ development. However, its role in uterine physiology has not yet been described. To study its regulation during the unique process of differentiation of fibroblasts into decidual cells (decidualization), we utilized the human uterine fibroblast (HuF) in vitro cell model. Immunocytochemistry data demonstrated that the majority of the TAZ protein is localized in the nucleus. Treatment of HuF cells with the embryonic stimulus cytokine interleukin 1 beta in the presence of steroid hormones (estradiol-17 beta and medroxyprogesterone acetate) for 13 days did not cause any apparent TAZ mRNA changes but resulted in a significant TAZ protein decline (approximately 62%) in total cell lysates. Analysis of cytosolic and nuclear extracts revealed that the decline of total TAZ was caused primarily by a drop of TAZ protein levels in the nucleus. TAZ was localized on the peroxisome proliferator-activated receptor response element site (located at position -1200 bp relative to the transcription start site) of the genomic region of decidualization marker insulin-like growth factor-binding protein 1 (IGFBP1) in HuF cells as detected by chromatin immunoprecipitation. TAZ is also present in human endometrium tissue as confirmed by immunohistochemistry. During the secretory phase of the menstrual cycle, specific TAZ staining particularly diminishes in the stroma, suggesting its participation during the decidualization process, as well as implantation. During early baboon pregnancy, TAZ protein expression remains minimal in the endometrium close to the implantation site. In summary, the presented evidence shows for the first time to date TAZ protein in the human uterine tract, its downregulation during in vitro decidualization, and its localization on the IGFBP1 promoter region, all of which indicate its presence in the uterine

  14. Cannabinoid receptor-2 selective antagonist negatively regulates receptor activator of nuclear factor kappa B ligand mediated osteoclastogenesis

    Institute of Scientific and Technical Information of China (English)

    GENG De-chun; XU Yao-zeng; YANG Hui-lin; ZHU Guang-ming; WANG Xian-bin; ZHU Xue-song

    2011-01-01

    Background The cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK) ligand (RANKL)induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.Methods RAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase (TRAP) staining using a commercial kit. Total ribonucleic acid (RNA)was isolated and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was done to examine the expression of RANK, cathepsin K (CPK) and nuclear factor kappa B (NF-κB). The extracellular signal-regulated kinase (ERK),phosphorylation of ERK (P-ERK) and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.Results AM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of >100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.Conclusion AM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.

  15. Relationship between muscular atrophy and peroxisome proliferator-activated receptor γ coactivator 1 alpha%肌肉萎缩与过氧化体增殖活化受体辅γ助活化因子1α的关系

    Institute of Scientific and Technical Information of China (English)

    杨殊; 文野

    2011-01-01

    BACKGROUND: Peroxisome proliferator-activated receptor . Coactivator 1 alpha (PGC-1a) can regulate numerous skeletal muscle functions including mitochondrial biogenesis, substrate oxidation, and muscle fibre type. Recently, PGC-1a has been found to prevent against muscular atrophy. OBJECTIVE: To summarize and discuss the relationship between PGC-1a and muscular atrophy. METHODS: A computer-based online retrieval of CNKI and Medline databases was performed by the first author to search papers published between 2000 and 2010 using the key words “muscle atrophy, PGC-1a, exercise” in Chinese or English. A total of 56 papers were retrieved. According to inclusion and exclusion criteria, 22 papers were included in the final analysis. These papers were summarized from PGC-1a and muscular atrophy, and exercise and PGC-1a. RESULTS AND CONCLUSION: Enhanced PGC-1a expression can enhance mitochondrial function and human sport ability, reduce oxidative stress and inhibit the expression of muscular atrophy specific gene. Therefore, exercise may inhibit muscular atrophy by regulating PGC-1a expression.%背景:过氧化体增殖活化受体γ 辅助活化因子1α(peroxisome proliferator-activated receptorγ coactivator 1α,PGC-1α)能调节骨骼肌的功能,包括有:线粒体的生物发生、底物氧化和肌纤维类型等,最近还有研究发现PGC-1α 能够预防肌肉的萎缩.目的:总结并讨论PGC-1α 与肌肉萎缩之间的关系.方法:由第一作者用计算机检索中国期刊全文数据库(CNKI:2000/2010)和Medline 数据库(2000/2010),关键词分别为"肌肉萎缩,PGC-1α,运动"和"muscle atrophy,PGC-1α,exercise".共检索到56 篇文章,按纳入和排除标准对文献进行筛选,共纳入22 篇文章.从PGC-1α 与肌肉萎缩、运动与PGC-1α 共2 个方面进行总结.结果与结论:PGC-1α 表达增强能提高线粒体功能、人体的运动能力、降低氧化应激和抑制肌肉萎缩特异性基因的表达.

  16. Molecular mechanism for the involvement of nuclear receptor FXR in HBV-associated hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Yong-dong Niu

    2011-08-01

    Full Text Available Farnesoid X receptor (FXR, also termed nuclear receptor NR1H4 is critically involved in the regulation of nascent bile formation and bile acid enterohepatic circulation. FXR and bile acids have been shown to play roles in liver regeneration and inflammatory responses. There is increasing evidence suggesting that FXR and the FXR signaling pathway are involved in the pathophysiology of a wide range of liver diseases, such as viral hepatitis, cirrhosis, and hepatocellular carcinoma (HCC. Here we discuss the latest discoveries of FXR functions with relevance to bile acid metabolism and HBV-associated HCC. More specifically, the goal of this review is to discuss the roles of FXR and bile acids in regulating HBV replication and how disregulation of the FXR-bile acid signaling pathway is involved in HBV-associated hepatocarcinogenesis.

  17. Action mechanisms of Liver X Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Gabbi, Chiara; Warner, Margaret [Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas (United States); Gustafsson, Jan-Åke, E-mail: jgustafs@central.uh.edu [Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas (United States); Department of Biosciences and Nutrition, Karolinska Institutet, Novum S-141 86 (Sweden)

    2014-04-11

    Highlights: • LXRα and LXRβ are ligand-activated nuclear receptors. • They share oxysterol ligands and the same heterodimerization partner, RXR. • LXRs regulate lipid and glucose metabolism, CNS and immune functions, and water transport. - Abstract: The two Liver X Receptors, LXRα and LXRβ, are nuclear receptors belonging to the superfamily of ligand-activated transcription factors. They share more than 78% homology in amino acid sequence, a common profile of oxysterol ligands and the same heterodimerization partner, Retinoid X Receptor. LXRs play crucial roles in several metabolic pathways: lipid metabolism, in particular in preventing cellular cholesterol accumulation; glucose homeostasis; inflammation; central nervous system functions and water transport. As with all nuclear receptors, the transcriptional activity of LXR is the result of an orchestration of numerous cellular factors including ligand bioavailability, presence of corepressors and coactivators and cellular context i.e., what other pathways are activated in the cell at the time the receptor recognizes its ligand. In this mini-review we summarize the factors regulating the transcriptional activity and the mechanisms of action of these two receptors.

  18. Transcriptional activation of NAD{sup +}-dependent protein deacetylase SIRT1 by nuclear receptor TLX

    Energy Technology Data Exchange (ETDEWEB)

    Iwahara, Naotoshi [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan); Hisahara, Shin; Hayashi, Takashi [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan); Department of Neurology, Sapporo Medical University, Sapporo 060-8556 (Japan); Horio, Yoshiyuki, E-mail: horio@sapmed.ac.jp [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan)

    2009-09-04

    An orphan nuclear receptor TLX is a transcriptional repressor that promotes the proliferation and self-renewal of neural precursor cells (NPCs). SIRT1, an NAD{sup +}-dependent protein deacetylase, is highly expressed in the NPCs and participates in neurogenesis. Here, we found that TLX colocalized with SIRT1 and knockdown of TLX by small interfering RNAs decreased SIRT1 levels in NPCs. TLX increased the SIRT1 expression by binding to the newly identified TLX-activating element in the SIRT1 gene promoter in HEK293 cells. Thus, TLX is an inducer of SIRT1 and may contribute to neurogenesis both as a transactivator and as a repressor.

  19. Mapping functional group free energy patterns at protein occluded sites: nuclear receptors and G-protein coupled receptors.

    Science.gov (United States)

    Lakkaraju, Sirish Kaushik; Yu, Wenbo; Raman, E Prabhu; Hershfeld, Alena V; Fang, Lei; Deshpande, Deepak A; MacKerell, Alexander D

    2015-03-23

    Occluded ligand-binding pockets (LBP) such as those found in nuclear receptors (NR) and G-protein coupled receptors (GPCR) represent a significant opportunity and challenge for computer-aided drug design. To determine free energies maps of functional groups of these LBPs, a Grand-Canonical Monte Carlo/Molecular Dynamics (GCMC/MD) strategy is combined with the Site Identification by Ligand Competitive Saturation (SILCS) methodology. SILCS-GCMC/MD is shown to map functional group affinity patterns that recapitulate locations of functional groups across diverse classes of ligands in the LBPs of the androgen (AR) and peroxisome proliferator-activated-γ (PPARγ) NRs and the metabotropic glutamate (mGluR) and β2-adreneric (β2AR) GPCRs. Inclusion of protein flexibility identifies regions of the binding pockets not accessible in crystal conformations and allows for better quantitative estimates of relative ligand binding affinities in all the proteins tested. Differences in functional group requirements of the active and inactive states of the β2AR LBP were used in virtual screening to identify high efficacy agonists targeting β2AR in Airway Smooth Muscle (ASM) cells. Seven of the 15 selected ligands were found to effect ASM relaxation representing a 46% hit rate. Hence, the method will be of use for the rational design of ligands in the context of chemical biology and the development of therapeutic agents.

  20. Reporter Cell Lines for the Characterization of the Interactions between Human Nuclear Receptors and Endocrine Disruptors.

    Science.gov (United States)

    Grimaldi, Marina; Boulahtouf, Abdelhay; Delfosse, Vanessa; Thouennon, Erwan; Bourguet, William; Balaguer, Patrick

    2015-01-01

    Endocrine-disrupting chemicals (EDCs) are exogenous substances interfering with hormone biosynthesis, metabolism, or action, and consequently causing disturbances in the endocrine system. Various pathways are activated by EDCs, including interactions with nuclear receptors (NRs), which are primary targets of numerous environmental contaminants. The main NRs targeted by environmental contaminants are the estrogen (ER α, β) and the androgen (AR) receptors. ERs and AR have pleiotropic regulatory roles in a diverse range of tissues, notably in the mammary gland, the uterus, and the prostate. Thus, dysfunctional ERs and AR signaling due to inappropriate exposure to environmental pollutants may lead to hormonal cancers and infertility. The pregnane X receptor (PXR) is also recognized by many environmental molecules. PXR has a protective role of the body through its ability to regulate proteins involved in the metabolism, the conjugation, and the transport of many exogenous and endogenous compounds. However, the permanent activation of this receptor by xenobiotics may lead to premature drug metabolism, the formation, and accumulation of toxic metabolites and defects in hormones homeostasis. The activity of other NRs can also be affected by environmental molecules. Compounds capable of inhibiting or activating the estrogen related (ERRγ), the thyroid hormone (TRα, β), the retinoid X receptors (RXRα, β, γ), and peroxisome proliferator-activated (PPAR α, γ) receptors have been identified and are highly suspected to promote developmental, reproductive, neurological, or metabolic diseases in humans and wildlife. In this review, we provide an overview of reporter cell lines established to characterize the human NR activities of a large panel of EDCs including natural as well as industrial compounds such as pesticides, plasticizers, surfactants, flame retardants, and cosmetics.

  1. Reporter cell lines for the characterization of the interactions between nuclear receptors and endocrine disruptors

    Directory of Open Access Journals (Sweden)

    marina egrimaldi

    2015-05-01

    Full Text Available Endocrine-disrupting chemicals (EDCs are exogenous substances interfering with hormone biosynthesis, metabolism, or action, and consequently causing disturbances in the endocrine system. Various pathways are activated by EDCs, including interactions with nuclear receptors (NRs which are primary targets of numerous environmental contaminants.The main NRs targeted by environmental contaminants are the estrogen (ER α, β and the androgen (AR receptors. ERs and AR have pleiotropic regulatory roles in a diverse range of tissues, notably in the mammary gland, the uterus and the prostate. Thus, dysfunctional ERs and AR signaling due to inappropriate exposure to environmental pollutants may lead to hormonal cancers and infertility. The pregnane X receptor (PXR is also recognized by many environmental molecules. PXR has a protective role of the body through its ability to regulate proteins involved in the metabolism, the conjugation and the transport of many exogenous and endogenous compounds. However, the permanent activation of this receptor by xenobiotics may lead to premature drug metabolism, the formation and accumulation of toxic metabolites and defects in hormones homeostasis. The activity of other NRs can also be affected by environmental molecules. Compounds capable of inhibiting or activating the estrogen related (ERRγ, the thyroid hormone (TRα, β, the retinoid X receptors (RXRα, β, γ and peroxisome proliferator-activated (PPAR α, γ receptors have been identified and are highly suspected to promote developmental, reproductive, neurological, or metabolic diseases in humans and wildlife.In this review we provide an overview of reporter cell lines established to characterize the human NR activities of a large panel of EDCs including natural as well as industrial compounds such as pesticides, plasticizers, surfactants, flame retardants and cosmetics.

  2. Genome inventory and analysis of nuclear hormone receptors in Tetraodon nigroviridis

    Indian Academy of Sciences (India)

    Raghu Prasad Rao Metpally; Ramakrishnan Vigneshwar; Ramanathan Sowdhamini

    2007-01-01

    Nuclear hormone receptors (NRs) form a large superfamily of ligand-activated transcription factors, which regulate genes underlying a wide range of (patho) physiological phenomena. Availability of the full genome sequence of Tetraodon nigroviridis facilitated a genome wide analysis of the NRs in fish genome. Seventy one NRs were found in Tetraodon and were compared with mammalian and fish NR family members. In general, there is a higher representation of NRs in fish genomes compared to mammalian ones. They showed high diversity across classes as observed by phylogenetic analysis. Nucleotide substitution rates show strong negative selection among fish NRs except for pregnane X receptor (PXR), estrogen receptor (ER) and liver X receptor (LXR). This may be attributed to crucial role played by them in metabolism and detoxification of xenobiotic and endobiotic compounds and might have resulted in slight positive selection. Chromosomal mapping and pairwise comparisons of NR distribution in Tetraodon and humans led to the identification of nine syntenic NR regions, of which three are common among fully sequenced vertebrate genomes. Gene structure analysis shows strong conservation of exon structures among orthologoues. Whereas paralogous members show different splicing patterns with intron gain or loss and addition or substitution of exons played a major role in evolution of NR superfamily.

  3. Targeting Nuclear Receptors with Lentivirus-Delivered Small RNAs in Primary Human Hepatocytes

    Directory of Open Access Journals (Sweden)

    Maria Thomas

    2014-07-01

    Full Text Available Background: RNA interference (RNAi has tremendous potential for investigating gene function and for developing new therapies. Primary human hepatocytes (PHH are the “gold standard” for studying the regulation of hepatic metabolism in vitro. However, application of RNAi in PHH has some technical hurdles. The objective of this study was to develop effective and robust protocol for transduction of PHH with lentiviral vectors. Methods: We used lentiviral vectors to transduce PHH for introduction of short hairpin RNAs (shRNAs targeting constitutive androstane receptor (CAR, peroxisome proliferator activated receptor alpha (PPARα, and microRNA, miR-143. Infection efficiency was quantitatively analyzed by flow cytometry and microscopy. Target gene expression was assessed using quantitative real-time (qRT-PCR method. Results: Lentiviral vector transduction resulted in ≥95% of infected cells at low multiplicity of infection (MOI of 3, which did not impair cellular viability. We demonstrated the feasibility of this technique in studies on targeting nuclear receptors, PPARα and CAR, with shRNAs as well as in lentivirus-mediated overexpression and knock-down of miRNA-143 experiments. Conclusions: We developed an efficient and robust protocol with standardized procedures for virus production, method of titer determination, and infection procedure for RNAi in primary human hepatocytes based on delivery of shRNAs, microRNAs or anti-microRNAs in different laboratory settings. This approach should be useful to study not only the regulation via nuclear receptors but also other biological, pharmacological, and toxicological aspects of drug metabolism.

  4. Challenges predicting ligand-receptor interactions of promiscuous proteins: the nuclear receptor PXR.

    Directory of Open Access Journals (Sweden)

    Sean Ekins

    2009-12-01

    Full Text Available Transcriptional regulation of some genes involved in xenobiotic detoxification and apoptosis is performed via the human pregnane X receptor (PXR which in turn is activated by structurally diverse agonists including steroid hormones. Activation of PXR has the potential to initiate adverse effects, altering drug pharmacokinetics or perturbing physiological processes. Reliable computational prediction of PXR agonists would be valuable for pharmaceutical and toxicological research. There has been limited success with structure-based modeling approaches to predict human PXR activators. Slightly better success has been achieved with ligand-based modeling methods including quantitative structure-activity relationship (QSAR analysis, pharmacophore modeling and machine learning. In this study, we present a comprehensive analysis focused on prediction of 115 steroids for ligand binding activity towards human PXR. Six crystal structures were used as templates for docking and ligand-based modeling approaches (two-, three-, four- and five-dimensional analyses. The best success at external prediction was achieved with 5D-QSAR. Bayesian models with FCFP_6 descriptors were validated after leaving a large percentage of the dataset out and using an external test set. Docking of ligands to the PXR structure co-crystallized with hyperforin had the best statistics for this method. Sulfated steroids (which are activators were consistently predicted as non-activators while, poorly predicted steroids were docked in a reverse mode compared to 5alpha-androstan-3beta-ol. Modeling of human PXR represents a complex challenge by virtue of the large, flexible ligand-binding cavity. This study emphasizes this aspect, illustrating modest success using the largest quantitative data set to date and multiple modeling approaches.

  5. Yes and Lyn play a role in nuclear translocation of the epidermal growth factor receptor.

    Science.gov (United States)

    Iida, M; Brand, T M; Campbell, D A; Li, C; Wheeler, D L

    2013-02-07

    The epidermal growth factor receptor (EGFR) is a central regulator of tumor progression in human cancers. Cetuximab is an anti-EGFR antibody that has been approved for use in oncology. Previously we investigated mechanisms of resistance to cetuximab using a model derived from the non-small cell lung cancer line NCI-H226. We demonstrated that cetuximab-resistant clones (Ctx(R)) had increased nuclear localization of the EGFR. This process was mediated by Src family kinases (SFKs), and nuclear EGFR had a role in resistance to cetuximab. To better understand SFK-mediated nuclear translocation of EGFR, we investigated which SFK member(s) controlled this process as well as the EGFR tyrosine residues that are involved. Analyses of mRNA and protein expression indicated upregulation of the SFK members Yes (v-Yes-1 yamaguchi sarcoma viral oncogene) and Lyn (v-yes-1 Yamaguchi sarcoma viral-related oncogene homolog) in all Ctx(R) clones. Further, immunoprecipitation analysis revealed that EGFR interacts with Yes and Lyn in Ctx(R) clones, but not in cetuximab-sensitive (Ctx(S)) parental cells. Using RNAi interference, we found that knockdown of either Yes or Lyn led to loss of EGFR translocation to the nucleus. Conversely, overexpression of Yes or Lyn in low nuclear EGFR-expressing Ctx(S) parental cells led to increased nuclear EGFR. Chromatin immunoprecipitation (ChIP) assays confirmed nuclear EGFR complexes associated with the promoter of the known EGFR target genes B-Myb and iNOS. Further, all Ctx(R) clones exhibited upregulation of B-Myb and iNOS at the mRNA and protein levels. siRNAs directed at Yes or Lyn led to decreased binding of EGFR complexes to the B-Myb and iNOS promoters based on ChIP analyses. SFKs have been shown to phosphorylate EGFR on tyrosines 845 and 1101 (Y845 and Y1101), and mutation of Y1101, but not Y845, impaired nuclear entry of the EGFR. Taken together, our findings demonstrate that Yes and Lyn phosphorylate EGFR at Y1101, which influences EGFR

  6. Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

    Science.gov (United States)

    Kim, Sun-Gyun; Lee, Bora; Kim, Dae-Hwan; Kim, Juhee; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

    2013-10-01

    Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

  7. Structural and Biochemical Basis for the Binding Selectivity of Peroxisome Proliferator-activated Receptor [gamma] to PGC-1[alpha

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong; Kovach, Amanda; Suino-Powell, Kelly; Martynowski, Dariusz; Xu, H. Eric (Pitt); (Van Andel)

    2008-07-23

    The functional interaction between the peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) and its coactivator PGC-1{alpha} is crucial for the normal physiology of PPAR{gamma} and its pharmacological response to antidiabetic treatment with rosiglitazone. Here we report the crystal structure of the PPAR{gamma} ligand-binding domain bound to rosiglitazone and to a large PGC-1{alpha} fragment that contains two LXXLL-related motifs. The structure reveals critical contacts mediated through the first LXXLL motif of PGC-1{alpha} and the PPAR{gamma} coactivator binding site. Through a combination of biochemical and structural studies, we demonstrate that the first LXXLL motif is the most potent among all nuclear receptor coactivator motifs tested, and only this motif of the two LXXLL-related motifs in PGC-1{alpha} is capable of binding to PPAR{gamma}. Our studies reveal that the strong interaction of PGC-1{alpha} and PPAR{gamma} is mediated through both hydrophobic and specific polar interactions. Mutations within the context of the full-length PGC-1{alpha} indicate that the first PGC-1{alpha} motif is necessary and sufficient for PGC-1{alpha} to coactivate PPAR{gamma} in the presence or absence of rosiglitazone. These results provide a molecular basis for specific recruitment and functional interplay between PPAR{gamma} and PGC-1{alpha} in glucose homeostasis and adipocyte differentiation.

  8. Nuclear Receptor Small Heterodimer Partner in Apoptosis Signaling and Liver Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxia; Wang, Li, E-mail: l.wang@hsc.utah.edu [Departments of Medicine and Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84132 (United States)

    2011-01-05

    Small heterodimer partner (SHP, NR0B2) is a unique orphan nuclear receptor that contains the dimerization and a putative ligand-binding domain, but lacks the conserved DNA binding domain. SHP exerts its physiological function as an inhibitor of gene transcription through physical interaction with multiple nuclear receptors and transcriptional factors. SHP is a critical transcriptional regulator affecting diverse biological functions, including bile acid, cholesterol and lipid metabolism, glucose and energy homeostasis, and reproductive biology. Recently, we and others have demonstrated that SHP is an epigenetically regulated transcriptional repressor that suppresses the development of liver cancer. In this review, we summarize recent major findings regarding the role of SHP in cell proliferation, apoptosis, and DNA methylation, and discuss recent progress in understanding the function of SHP as a tumor suppressor in the development of liver cancer. Future study will be focused on identifying SHP associated novel prooncogenes and anti-oncogenes in liver cancer progression and applying the knowledge gained on SHP in liver cancer prevention, diagnosis and treatment.

  9. Thyroid Hormone Receptor α1 Follows a Cooperative CRM1/Calreticulin-mediated Nuclear Export Pathway*

    Science.gov (United States)

    Grespin, Matthew E.; Bonamy, Ghislain M. C.; Roggero, Vincent R.; Cameron, Nicole G.; Adam, Lindsay E.; Atchison, Andrew P.; Fratto, Victoria M.; Allison, Lizabeth A.

    2008-01-01

    The thyroid hormone receptor α1 (TRα) exhibits a dual role as an activator or repressor of its target genes in response to thyroid hormone (T3). Previously, we have shown that TRα, formerly thought to reside solely in the nucleus bound to DNA, actually shuttles rapidly between the nucleus and cytoplasm. An important aspect of the shuttling activity of TRα is its ability to exit the nucleus through the nuclear pore complex. TRα export is not sensitive to treatment with the CRM1-specific inhibitor leptomycin B (LMB) in heterokaryon assays, suggesting a role for an export receptor other than CRM1. Here, we have used a combined approach of in vivo fluorescence recovery after photobleaching experiments, in vitro permeabilized cell nuclear export assays, and glutathione S-transferase pull-down assays to investigate the export pathway used by TRα. We show that, in addition to shuttling in heterokaryons, TRα shuttles rapidly in an unfused monokaryon system as well. Furthermore, our data show that TRα directly interacts with calreticulin, and point to the intriguing possibility that TRα follows a cooperative export pathway in which both calreticulin and CRM1 play a role in facilitating efficient translocation of TRα from the nucleus to cytoplasm. PMID:18641393

  10. Thyroid hormone receptor alpha1 follows a cooperative CRM1/calreticulin-mediated nuclear export pathway.

    Science.gov (United States)

    Grespin, Matthew E; Bonamy, Ghislain M C; Roggero, Vincent R; Cameron, Nicole G; Adam, Lindsay E; Atchison, Andrew P; Fratto, Victoria M; Allison, Lizabeth A

    2008-09-12

    The thyroid hormone receptor alpha1 (TRalpha) exhibits a dual role as an activator or repressor of its target genes in response to thyroid hormone (T(3)). Previously, we have shown that TRalpha, formerly thought to reside solely in the nucleus bound to DNA, actually shuttles rapidly between the nucleus and cytoplasm. An important aspect of the shuttling activity of TRalpha is its ability to exit the nucleus through the nuclear pore complex. TRalpha export is not sensitive to treatment with the CRM1-specific inhibitor leptomycin B (LMB) in heterokaryon assays, suggesting a role for an export receptor other than CRM1. Here, we have used a combined approach of in vivo fluorescence recovery after photobleaching experiments, in vitro permeabilized cell nuclear export assays, and glutathione S-transferase pull-down assays to investigate the export pathway used by TRalpha. We show that, in addition to shuttling in heterokaryons, TRalpha shuttles rapidly in an unfused monokaryon system as well. Furthermore, our data show that TRalpha directly interacts with calreticulin, and point to the intriguing possibility that TRalpha follows a cooperative export pathway in which both calreticulin and CRM1 play a role in facilitating efficient translocation of TRalpha from the nucleus to cytoplasm.

  11. The Nuclear Orphan Receptor NR2F6 Is a Central Checkpoint for Cancer Immune Surveillance

    Directory of Open Access Journals (Sweden)

    Natascha Hermann-Kleiter

    2015-09-01

    Full Text Available Nuclear receptor subfamily 2, group F, member 6 (NR2F6 is an orphan member of the nuclear receptor superfamily. Here, we show that genetic ablation of Nr2f6 significantly improves survival in the murine transgenic TRAMP prostate cancer model. Furthermore, Nr2f6−/− mice spontaneously reject implanted tumors and develop host-protective immunological memory against tumor rechallenge. This is paralleled by increased frequencies of both CD4+ and CD8+ T cells and higher expression levels of interleukin 2 and interferon γ at the tumor site. Mechanistically, CD4+ and CD8+ T cell-intrinsic NR2F6 acts as a direct repressor of the NFAT/AP-1 complex on both the interleukin 2 and the interferon γ cytokine promoters, attenuating their transcriptional thresholds. Adoptive transfer of Nr2f6-deficient T cells into tumor-bearing immunocompetent mice is sufficient to delay tumor outgrowth. Altogether, this defines NR2F6 as an intracellular immune checkpoint in effector T cells, governing the amplitude of anti-cancer immunity.

  12. The orphan nuclear receptor SHP regulates PGC-1alpha expression and energy production in brown adipocytes.

    Science.gov (United States)

    Wang, Li; Liu, Jun; Saha, Pradip; Huang, Jiansheng; Chan, Lawrence; Spiegelman, Bruce; Moore, David D

    2005-10-01

    Brown adipocytes increase energy production in response to induction of PGC-1alpha, a dominant regulator of energy metabolism. We have found that the orphan nuclear receptor SHP (NR0B2) is a negative regulator of PGC-1alpha expression in brown adipocytes. Mice lacking SHP show increased basal expression of PGC-1alpha, increased energy expenditure, and resistance to diet-induced obesity. Increased PGC-1alpha expression in SHP null brown adipose tissue is not due to beta-adrenergic activation, since it is also observed in primary cultures of SHP(-/-) brown adipocytes that are not exposed to such stimuli. In addition, acute inhibition of SHP expression in cultured wild-type brown adipocytes increases basal PGC-1alpha expression, and SHP overexpression in SHP null brown adipocytes decreases it. The orphan nuclear receptor ERRgamma is expressed in BAT and its transactivation of the PGC-1alpha promoter is potently inhibited by SHP. We conclude that SHP functions as a negative regulator of energy production in BAT.

  13. Discriminating agonist and antagonist ligands of the nuclear receptors using 3D-pharmacophores.

    Science.gov (United States)

    Lagarde, Nathalie; Delahaye, Solenne; Zagury, Jean-François; Montes, Matthieu

    2016-01-01

    Nuclear receptors (NRs) constitute an important class of therapeutic targets. We evaluated the performance of 3D structure-based and ligand-based pharmacophore models in predicting the pharmacological profile of NRs ligands using the NRLiSt BDB database. We could generate selective pharmacophores for agonist and antagonist ligands and we found that the best performances were obtained by combining the structure-based and the ligand-based approaches. The combination of pharmacophores that were generated allowed to cover most of the chemical space of the NRLiSt BDB datasets. By screening the whole NRLiSt BDB on our 3D pharmacophores, we demonstrated their selectivity towards their dedicated NRs ligands. The 3D pharmacophores herein presented can thus be used as a predictor of the pharmacological activity of NRs ligands.Graphical AbstractUsing a combination of structure-based and ligand-based pharmacophores, agonist and antagonist ligands of the Nuclear Receptors included in the NRLiSt BDB database could be separated.

  14. Expression of bacterial alkaline phosphatase-steroid receptor coactivator-1 fusion protein and its application in regulation of drug metabolism enzymes%BAP-SRC-1融合蛋白的表达及其在药物代谢酶调控研究中的应用

    Institute of Scientific and Technical Information of China (English)

    陈亚坤; 陈枢青; 曾苏

    2005-01-01

    目的获得活性表达的细菌碱性磷酸酶(bacterial alkaline phosphatase,BAP)基因和人甾体受体辅活化因子-1(stero1d receptor coactivator-1,SRC-1)的融合蛋白,应用于辅活化因子与核受体的结合研究.方法从Escherichia coli JM83基因组和人肝总RNA中分别扩增获得BAP基因和SRC-1的186个氨基酸对应的基因序列(简称SRC186).用重组技术,构建BAP-SRC186-pET28a融合基因表达载体,在Escherichia coli Rosetta(DE3)中,以IPTG低温诱导表达.以对硝基苯磷酸盐(p-nitrophenyl-phos-phate,PNPP)为底物进行活性测定.活性表达的BAP-SRC186融合蛋白被应用于辅活化因子与核受体的结合研究.结果获得可溶性融合蛋白BAP-SRC186.该融合蛋白的BAP比活为(0.176±0.013 4)μmol·min-1·mg(pro).在利福平存在的情况下,BAP-SRC186能与孕烷X受体配体结合域(pregnane X receptor ligand binding domain,PXRLBD)发生利福平剂量依赖性的相互作用,作用强度通过BAP的显色反应可方便地检测.结论 BAP融合蛋白与核受体的结合研究为药物代谢酶调控的体外研究开辟了新的思路.

  15. The human gonadotropin releasing hormone type I receptor is a functional intracellular GPCR expressed on the nuclear membrane.

    Directory of Open Access Journals (Sweden)

    Michelle Re

    Full Text Available The mammalian type I gonadotropin releasing hormone receptor (GnRH-R is a structurally unique G protein-coupled receptor (GPCR that lacks cytoplasmic tail sequences and displays inefficient plasma membrane expression (PME. Compared to its murine counterparts, the primate type I receptor is inefficiently folded and retained in the endoplasmic reticulum (ER leading to a further reduction in PME. The decrease in PME and concomitant increase in intracellular localization of the mammalian GnRH-RI led us to characterize the spatial distribution of the human and mouse GnRH receptors in two human cell lines, HEK 293 and HTR-8/SVneo. In both human cell lines we found the receptors were expressed in the cytoplasm and were associated with the ER and nuclear membrane. A molecular analysis of the receptor protein sequence led us to identify a putative monopartite nuclear localization sequence (NLS in the first intracellular loop of GnRH-RI. Surprisingly, however, neither the deletion of the NLS nor the addition of the Xenopus GnRH-R cytoplasmic tail sequences to the human receptor altered its spatial distribution. Finally, we demonstrate that GnRH treatment of nuclei isolated from HEK 293 cells expressing exogenous GnRH-RI triggers a significant increase in the acetylation and phosphorylation of histone H3, thereby revealing that the nuclear-localized receptor is functional. Based on our findings, we conclude that the mammalian GnRH-RI is an intracellular GPCR that is expressed on the nuclear membrane. This major and novel discovery causes us to reassess the signaling potential of this physiologically and clinically important receptor.

  16. The human gonadotropin releasing hormone type I receptor is a functional intracellular GPCR expressed on the nuclear membrane.

    Science.gov (United States)

    Re, Michelle; Pampillo, Macarena; Savard, Martin; Dubuc, Céléna; McArdle, Craig A; Millar, Robert P; Conn, P Michael; Gobeil, Fernand; Bhattacharya, Moshmi; Babwah, Andy V

    2010-07-08

    The mammalian type I gonadotropin releasing hormone receptor (GnRH-R) is a structurally unique G protein-coupled receptor (GPCR) that lacks cytoplasmic tail sequences and displays inefficient plasma membrane expression (PME). Compared to its murine counterparts, the primate type I receptor is inefficiently folded and retained in the endoplasmic reticulum (ER) leading to a further reduction in PME. The decrease in PME and concomitant increase in intracellular localization of the mammalian GnRH-RI led us to characterize the spatial distribution of the human and mouse GnRH receptors in two human cell lines, HEK 293 and HTR-8/SVneo. In both human cell lines we found the receptors were expressed in the cytoplasm and were associated with the ER and nuclear membrane. A molecular analysis of the receptor protein sequence led us to identify a putative monopartite nuclear localization sequence (NLS) in the first intracellular loop of GnRH-RI. Surprisingly, however, neither the deletion of the NLS nor the addition of the Xenopus GnRH-R cytoplasmic tail sequences to the human receptor altered its spatial distribution. Finally, we demonstrate that GnRH treatment of nuclei isolated from HEK 293 cells expressing exogenous GnRH-RI triggers a significant increase in the acetylation and phosphorylation of histone H3, thereby revealing that the nuclear-localized receptor is functional. Based on our findings, we conclude that the mammalian GnRH-RI is an intracellular GPCR that is expressed on the nuclear membrane. This major and novel discovery causes us to reassess the signaling potential of this physiologically and clinically important receptor.

  17. Regulation of homocysteine homeostasis through the transcriptional coactivator PGC-1alpha.

    Science.gov (United States)

    Li, Siming; Arning, Erland; Liu, Chang; Vitvitsky, Victor; Hernandez, Carlos; Banerjee, Ruma; Bottiglieri, Teodoro; Lin, Jiandie D

    2009-03-01

    Plasma homocysteine (Hcy) is an independent risk factor for cardiovascular disease. Hcy is a nonprotein amino acid derivative that is generated from the methionine cycle, which provides the methyl group for essentially all biological methylation reactions. Although plasma Hcy levels are elevated in patients with cardiovascular disease, the mechanisms that regulate Hcy homeostasis remain poorly defined. In this study, we found that the expression of key enzymes involved in Hcy metabolism is induced in the liver in response to fasting. This induction coincides with increased expression of peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha, a transcriptional coactivator that regulates hepatic gluconeogenesis and mitochondrial function. PGC-1alpha stimulates the expression of genes involved in Hcy metabolism in cultured primary hepatocytes as well as in the liver. Adenoviral-mediated expression of PGC-1alpha in vivo leads to elevated plasma Hcy levels. In contrast, mice deficient in PGC-1alpha have lower plasma Hcy concentrations. These results define a novel role for the PGC-1alpha coactivator pathway in the regulation of Hcy homeostasis and suggest a potential pathogenic mechanism that contributes to hyperhomocysteinemia.

  18. SRC-2 Is an Essential Coactivator for Orchestrating Metabolism and Circadian Rhythm

    Directory of Open Access Journals (Sweden)

    Erin Stashi

    2014-02-01

    Full Text Available Synchrony of the mammalian circadian clock is achieved by complex transcriptional and translational feedback loops centered on the BMAL1:CLOCK heterodimer. Modulation of circadian feedback loops is essential for maintaining rhythmicity, yet the role of transcriptional coactivators in driving BMAL1:CLOCK transcriptional networks is largely unexplored. Here, we show diurnal hepatic steroid receptor coactivator 2 (SRC-2 recruitment to the genome that extensively overlaps with the BMAL1 cistrome during the light phase, targeting genes that enrich for circadian and metabolic processes. Notably, SRC-2 ablation impairs wheel-running behavior, alters circadian gene expression in several peripheral tissues, alters the rhythmicity of the hepatic metabolome, and deregulates the synchronization of cell-autonomous metabolites. We identify SRC-2 as a potent coregulator of BMAL1:CLOCK and find that SRC-2 targets itself with BMAL1:CLOCK in a feedforward loop. Collectively, our data suggest that SRC-2 is a transcriptional coactivator of the BMAL1:CLOCK oscillators and establish SRC-2 as a critical positive regulator of the mammalian circadian clock.

  19. The nuclear melatonin receptor RORα is a novel endogenous defender against myocardial ischemia/reperfusion injury.

    Science.gov (United States)

    He, Ben; Zhao, Yichao; Xu, Longwei; Gao, Lingchen; Su, Yuanyuan; Lin, Nan; Pu, Jun

    2016-04-01

    Circadian rhythm disruption or decrease in levels of circadian hormones such as melatonin increases ischemic heart disease risk. The nuclear melatonin receptors RORs are pivotally involved in circadian rhythm regulation and melatonin effects mediation. However, the functional roles of RORs in the heart have never been investigated and were therefore the subject of this study on myocardial ischemia/reperfusion (MI/R) injury pathogenesis. RORα and RORγ subtypes were detected in the adult mouse heart, and RORα but not RORγ was downregulated after MI/R. To determine the pathological consequence of MI/R-induced reduction of RORα, we subjected RORα-deficient staggerer mice and wild-type (WT) littermates to MI/R injury, resulting in significantly increased myocardial infarct size, myocardial apoptosis and exacerbated contractile dysfunction in the former. Mechanistically, RORα deficiency promoted MI/R-induced endoplasmic reticulum stress, mitochondrial impairments, and autophagy dysfunction. Moreover, RORα deficiency augmented MI/R-induced oxidative/nitrative stress. Given the emerging evidence of RORα as an essential melatonin effects mediator, we further investigated the RORα roles in melatonin-exerted cardioprotection, in particular against MI/R injury, which was significantly attenuated in RORα-deficient mice, but negligibly affected by cardiac-specific silencing of RORγ. Finally, to determine cell type-specific effects of RORα, we generated mice with cardiomyocyte-specific RORα overexpression and they were less vulnerable to MI/R injury. In summary, our study provides the first direct evidence that the nuclear melatonin receptor RORα is a novel endogenous protective receptor against MI/R injury and an important mediator of melatonin-exerted cardioprotection; melatonin-RORα axis signaling thus appears important in protection against ischemic heart injury.

  20. Plasticity of an ultrafast interaction between nucleoporins and nuclear transport receptors.

    Science.gov (United States)

    Milles, Sigrid; Mercadante, Davide; Aramburu, Iker Valle; Jensen, Malene Ringkjøbing; Banterle, Niccolò; Koehler, Christine; Tyagi, Swati; Clarke, Jane; Shammas, Sarah L; Blackledge, Martin; Gräter, Frauke; Lemke, Edward A

    2015-10-22

    The mechanisms by which intrinsically disordered proteins engage in rapid and highly selective binding is a subject of considerable interest and represents a central paradigm to nuclear pore complex (NPC) function, where nuclear transport receptors (NTRs) move through the NPC by binding disordered phenylalanine-glycine-rich nucleoporins (FG-Nups). Combining single-molecule fluorescence, molecular simulations, and nuclear magnetic resonance, we show that a rapidly fluctuating FG-Nup populates an ensemble of conformations that are prone to bind NTRs with near diffusion-limited on rates, as shown by stopped-flow kinetic measurements. This is achieved using multiple, minimalistic, low-affinity binding motifs that are in rapid exchange when engaging with the NTR, allowing the FG-Nup to maintain an unexpectedly high plasticity in its bound state. We propose that these exceptional physical characteristics enable a rapid and specific transport mechanism in the physiological context, a notion supported by single molecule in-cell assays on intact NPCs.

  1. Androgen receptor non-nuclear regulation of prostate cancer cell invasion mediated by Src and matriptase.

    Science.gov (United States)

    Zarif, Jelani C; Lamb, Laura E; Schulz, Veronique V; Nollet, Eric A; Miranti, Cindy K

    2015-03-30

    Castration-resistant prostate cancers still depend on nuclear androgen receptor (AR) function despite their lack of dependence on exogenous androgen. Second generation anti-androgen therapies are more efficient at blocking nuclear AR; however resistant tumors still develop. Recent studies indicate Src is highly active in these resistant tumors. By manipulating AR activity in several different prostate cancer cell lines through RNAi, drug treatment, and the use of a nuclear-deficient AR mutant, we demonstrate that androgen acting on cytoplasmic AR rapidly stimulates Src tyrosine kinase via a non-genomic mechanism. Cytoplasmic AR, acting through Src enhances laminin integrin-dependent invasion. Active Matriptase, which cleaves laminin, is elevated within minutes after androgen stimulation, and is subsequently shed into the medium. Matriptase activation and shedding induced by cytoplasmic AR is dependent on Src. Concomitantly, CDCP1/gp140, a Matriptase and Src substrate that controls integrin-based migration, is activated. However, only inhibition of Matriptase, but not CDCP1, suppresses the AR/Src-dependent increase in invasion. Matriptase, present in conditioned medium from AR-stimulated cells, is sufficient to enhance invasion in the absence of androgen. Thus, invasion is stimulated by a rapid but sustained increase in Src activity, mediated non-genomically by cytoplasmic AR, leading to rapid activation and shedding of the laminin protease Matriptase.

  2. Localización extra nuclear de receptores esteroides y activación de mecanismos no genómicos Extra nuclear localization of steroid receptors and non genomic activation mechanisms

    Directory of Open Access Journals (Sweden)

    María Cecilia Bottino

    2010-04-01

    Full Text Available Los receptores de hormonas esteroides han sido considerados históricamente como factores de transcripción nucleares. Sin embargo, en los últimos años surgieron evidencias que indican que su activación desencadena eventos rápidos, independientes de la transcripción y que involucran a diferentes segundos mensajeros; muchos de estos receptores han sido localizados en la membrana celular. Por otra parte, se han caracterizado varios receptores de hormonas esteroides noveles, de estructura molecular diferente al receptor clásico, localizados principalmente en la membrana celular. Esta revisión enfoca los diferentes efectos iniciados por los glucocorticoides, mineralocorticoides, andrógenos, estrógenos y progesterona, y los posibles receptores involucrados en los mismos.Steroid hormone receptors have been historically considered as nuclear transcription factors. Nevertheless, in the last years, many of them have been detected in the cellular membrane. It has been postulated that their activation can induce transcription independent rapid events involving different second messengers. In addition, several novel steroid hormone receptors, showing a different molecular structure than the classical ones, have also been characterized and most of them are also located in the plasmatic membrane. This review focuses on the variety of effects initiated by glucocorticoids, mineralocorticoids, androgens, estrogens and progesterone, and the possible receptors involved mediating these effects.

  3. Inactivation of the Nuclear Orphan Receptor COUP-TFII by Small Chemicals.

    Science.gov (United States)

    Le Guével, Rémy; Oger, Frédérik; Martinez-Jimenez, Celia P; Bizot, Maud; Gheeraert, Céline; Firmin, François; Ploton, Maheul; Kretova, Miroslava; Palierne, Gaëlle; Staels, Bart; Barath, Peter; Talianidis, Iannis; Lefebvre, Philippe; Eeckhoute, Jérôme; Salbert, Gilles

    2017-01-13

    Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII/NR2F2) is an orphan member of the nuclear receptor family of transcription factors whose activities are modulated upon binding of small molecules into an hydrophobic ligand-binding pocket (LBP). Although the LBP of COUP-TFII is filled with aromatic amino-acid side chains, alternative modes of ligand binding could potentially lead to regulation of the orphan receptor. Here, we screened a synthetic and natural compound library in a yeast one-hybrid assay and identified 4-methoxynaphthol as an inhibitor of COUP-TFII. This synthetic inhibitor was able to counteract processes either positively or negatively regulated by COUP-TFII in different mammalian cell systems. Hence, we demonstrate that the true orphan receptor COUP-TFII can be targeted by small chemicals which could be used to study the physiological functions of COUP-TFII or to counteract detrimental COUP-TFII activities in various pathological conditions.

  4. Annotation of the Daphnia magna nuclear receptors: comparison to Daphnia pulex.

    Science.gov (United States)

    Litoff, Elizabeth J; Garriott, Travis E; Ginjupalli, Gautam K; Butler, LaToya; Gay, Claudy; Scott, Kiandra; Baldwin, William S

    2014-11-15

    Most nuclear receptors (NRs) are ligand-dependent transcription factors crucial in homeostatic physiological responses or environmental responses. We annotated the Daphnia magna NRs and compared them to Daphnia pulex and other species, primarily through phylogenetic analysis. Daphnia species contain 26 NRs spanning all seven gene subfamilies. Thirteen of the 26 receptors found in Daphnia species phylogenetically segregate into the NR1 subfamily, primarily involved in energy metabolism and resource allocation. Some of the Daphnia NRs, such as RXR, HR96, and E75 show strong conservation between D. magna and D. pulex. Other receptors, such as EcRb, THRL-11 and RARL-10 have diverged considerably and therefore may show different functions in the two species. Curiously, there is an inverse association between the number of NR splice variants and conservation of the LBD. Overall, D. pulex and D. magna possess the same NRs; however not all of the NRs demonstrate high conservation indicating the potential for a divergence of function. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Nuclear receptor engineering based on novel structure activity relationships revealed by farnesyl pyrophosphate.

    Science.gov (United States)

    Goyanka, Ritu; Das, Sharmistha; Samuels, Herbert H; Cardozo, Timothy

    2010-11-01

    Nuclear receptors (NRs) comprise the second largest protein family targeted by currently available drugs, acting via specific ligand interactions within the ligand binding domain (LBD). Recently, farnesyl pyrophosphate (FPP) was shown to be a unique promiscuous NR ligand, activating a subset of NR family members and inhibiting wound healing in skin. The current study aimed at visualizing the unique basis of FPP interaction with multiple receptors in order to identify general structure-activity relationships that operate across the NR family. Docking of FPP to the 3D structures of the LBDs of a diverse set of NRs consistently revealed an electrostatic FPP pyrophosphate contact with an NR arginine conserved in the NR family, a hydrophobic farnesyl contact with NR helix-12 and a ligand binding pocket volume between 300 and 430 Å(3) as the minimal requirements for FPP activation of any NR. Lack of any of these structural features appears to render a given NR resistant to FPP activation. We used these structure-activity relationships to rationally design and successfully engineer several mutant human estrogen receptors that retain responsiveness to estradiol but no longer respond to FPP.

  6. Nuclear receptors of the peroxisome proliferator-activated receptor (PPAR) family in gestational diabetes: from animal models to clinical trials.

    Science.gov (United States)

    Arck, Petra; Toth, Bettina; Pestka, Aurelia; Jeschke, Udo

    2010-08-01

    Gestational diabetes mellitus (GDM) is defined as impaired glucose tolerance and affects 2%-8% of all pregnancies. Among other complications, GDM can lead to the development of type 2 diabetes mellitus (DM 2) in both mother and child. Peroxisome proliferator-activated receptors (PPARs) are major regulators of glucose and lipid metabolism. Furthermore, PPARs are mediators of inflammation and angiogenesis and are involved in the maternal adaptational dynamics during pregnancy to serve the requirements of the growing fetus. PPARs were originally named for their ability to induce hepatic peroxisome proliferation in mice in response to xenobiotic stimuli. The expression of three PPAR isoforms, alpha, beta/delta, and gamma, have been described. Each of them is encoded by different genes; however, they share 60%-80% homology in their ligand-binding and DNA-binding domains. PPARs are involved in trophoblast differentiation, invasion, metabolism, and parturition and are expressed in invasive extravillous trophoblast and villous trophoblast cells. Nuclear receptors, to which PPARs belong, are promising targets for disease-specific treatment strategies because they act as transcription factors controlling cellular processes at the level of gene expression and may produce selective alterations in downstream gene expression. To date, PPAR agonists are therapeutically used in patients with DM 2 and in patients with reproductive disorders such as polycystic ovary syndrome. Because of safety concerns and limited data, PPAR agonists are not yet included in GDM-related treatment strategies. Our objective herein is to review newly emerging generations of selective PPAR modulators and panagonists, which may have potent therapeutic implications in the context of GDM.

  7. Nuclear receptors HR96 and ultraspiracle from the fall armyworm (Spodoptera frugiperda), developmental expression and induction by xenobiotics.

    Science.gov (United States)

    Giraudo, Maeva; Audant, Pascaline; Feyereisen, René; Le Goff, Gaëlle

    2013-05-01

    The fall armyworm Spodoptera frugiperda is a major polyphagous pest in agriculture and little is known on how this insect can adapt to the diverse and potentially toxic plant allelochemicals that they ingest or to insecticides. To investigate the involvement of nuclear receptors in the response of S. frugiperda to its chemical environment, we cloned SfHR96, a nuclear receptor orthologous to the mammalian xenobiotic receptors, pregnane X receptor (PXR) and constitutive androstane receptor (CAR). We also cloned ultraspiracle (USP), the ortholog of retinoid X receptor (RXR) that serves as partner of dimerization of PXR and CAR. Cloning of SfUSP revealed the presence of two isoforms, SfUSP-1 and SfUSP-2 in this species, that differ in their N-terminal region. The expression of these receptors as well as the ecdysone receptor was studied during specific steps of development in different tissues. SfHR96 was constitutively expressed in larval midgut, fat body and Malpighian tubules throughout the last two instars and pupal stage, as well as in Sf9 cells. EcR and SfUSP-2 showed peaks of expression before larval moults and during metamorphosis, whereas SfUSP-1 was mainly expressed in the pre-pupal stage. Receptor induction was followed after exposure of larvae or cells to 11 chemical compounds. SfHR96 was not inducible by the tested compounds. EcR was significantly induced by the 20-hydroxyecdysone agonist, methoxyfenozide, and SfUSP showed an increase expression when exposed to the juvenile hormone analog, methoprene. The cloning of these nuclear receptors is a first step in understanding the important capacities of adaptation of this insect pest.

  8. Molecular adaptation and resilience of the insect’s nuclear receptor USP

    Directory of Open Access Journals (Sweden)

    Chaumot Arnaud

    2012-10-01

    Full Text Available Abstract Background The maintenance of biological systems requires plasticity and robustness. The function of the ecdysone receptor, a heterodimer composed of the nuclear receptors ECR (NR1H1 and USP (NR2B4, was maintained in insects despite a dramatic divergence that occurred during the emergence of Mecopterida. This receptor is therefore a good model to study the evolution of plasticity. We tested the hypothesis that selection has shaped the Ligand-Binding Domain (LBD of USP during evolution of Mecopterida. Results We isolated usp and cox1 in several species of Drosophilidae, Tenebrionidae and Blattaria and estimated non-synonymous/synonymous rate ratios using maximum-likelihood methods and codon-based substitution models. Although the usp sequences were mainly under negative selection, we detected relaxation at residues located on the surface of the LBD within Mecopterida families. Using branch-site models, we also detected changes in selective constraints along three successive branches of the Mecopterida evolution. Residues located at the bottom of the ligand-binding pocket (LBP underwent strong positive selection during the emergence of Mecopterida. This change is correlated with the acquisition of a large LBP filled by phospholipids that probably allowed the stabilisation of the new Mecopterida structure. Later, when the two subgroups of Mecopterida (Amphiesmenoptera: Lepidoptera, Trichoptera; Antliophora: Diptera, Mecoptera, Siphonaptera diverged, the same positions became under purifying selection. Similarly, several positions of the heterodimerisation interface experienced positive selection during the emergence of Mecopterida, rapidly followed by a phase of constrained evolution. An enlargement of the heterodimerisation surface is specific for Mecopterida and was associated with a reinforcement of the obligatory partnership between ECR and USP, at the expense of homodimerisation. Conclusions In order to explain the episodic mode of

  9. Localización extra nuclear de receptores esteroides y activación de mecanismos no genómicos Extra nuclear localization of steroid receptors and non genomic activation mechanisms

    OpenAIRE

    María Cecilia Bottino; Claudia Lanari

    2010-01-01

    Los receptores de hormonas esteroides han sido considerados históricamente como factores de transcripción nucleares. Sin embargo, en los últimos años surgieron evidencias que indican que su activación desencadena eventos rápidos, independientes de la transcripción y que involucran a diferentes segundos mensajeros; muchos de estos receptores han sido localizados en la membrana celular. Por otra parte, se han caracterizado varios receptores de hormonas esteroides noveles, de estructura molecula...

  10. An Extension of SIC Predictions to the Wiener Coactive Model.

    Science.gov (United States)

    Houpt, Joseph W; Townsend, James T

    2011-06-01

    The survivor interaction contrasts (SIC) is a powerful measure for distinguishing among candidate models of human information processing. One class of models to which SIC analysis can apply are the coactive, or channel summation, models of human information processing. In general, parametric forms of coactive models assume that responses are made based on the first passage time across a fixed threshold of a sum of stochastic processes. Previous work has shown that that the SIC for a coactive model based on the sum of Poisson processes has a distinctive down-up-down form, with an early negative region that is smaller than the later positive region. In this note, we demonstrate that a coactive process based on the sum of two Wiener processes has the same SIC form.

  11. BDNF Reduces Toxic Extrasynaptic NMDA Receptor Signaling via Synaptic NMDA Receptors and Nuclear-Calcium-Induced Transcription of inhba/Activin A

    Directory of Open Access Journals (Sweden)

    David Lau

    2015-08-01

    Full Text Available The health of neurons is critically dependent on the relative signaling intensities of survival-promoting synaptic and death-inducing extrasynaptic NMDA receptors. Here, we show that BDNF is a regulator of this balance and promotes neuroprotection by reducing toxic NMDA receptor signaling. BDNF acts by initiating synaptic NMDA-receptor/nuclear-calcium-driven adaptogenomics, leading to increased expression of inhibin β-A (inhba. Inhibin β-A (its homodimer is known as activin A in turn reduces neurotoxic extrasynaptic NMDA-receptor-mediated calcium influx, thereby shielding neurons against mitochondrial dysfunction, a major cause of excitotoxicity. Thus, BDNF induces acquired neuroprotection by enhancing synaptic activity and lowering extrasynaptic NMDA receptor death signaling through a nuclear calcium-inhibin β-A pathway. This process, which confers protection against ischemic brain damage in a mouse stroke model, may be compromised in Huntington’s disease, Alzheimer’s disease, or aging-related neurodegenerative conditions that are associated with reduced BDNF levels and/or enhanced extrasynaptic NMDA receptor signaling.

  12. Structural basis for cooperativity in recruitment of MAML coactivators to Notch transcription complexes.

    Science.gov (United States)

    Nam, Yunsun; Sliz, Piotr; Song, Luyan; Aster, Jon C; Blacklow, Stephen C

    2006-03-10

    Notch receptors transduce essential developmental signals between neighboring cells by forming a complex that leads to transcription of target genes upon activation. We report here the crystal structure of a Notch transcriptional activation complex containing the ankyrin domain of human Notch1 (ANK), the transcription factor CSL on cognate DNA, and a polypeptide from the coactivator Mastermind-like-1 (MAML-1). Together, CSL and ANK create a groove to bind the MAML-1 polypeptide as a kinked, 70 A helix. The composite binding surface likely restricts the recruitment of MAML proteins to promoters on which Notch:CSL complexes have been preassembled, ensuring tight transcriptional control of Notch target genes.

  13. Role of fatty acid binding proteins and long chain fatty acids in modulating nuclear receptors and gene transcription.

    Science.gov (United States)

    Schroeder, Friedhelm; Petrescu, Anca D; Huang, Huan; Atshaves, Barbara P; McIntosh, Avery L; Martin, Gregory G; Hostetler, Heather A; Vespa, Aude; Landrock, Danilo; Landrock, Kerstin K; Payne, H Ross; Kier, Ann B

    2008-01-01

    Abnormal energy regulation may significantly contribute to the pathogenesis of obesity, diabetes mellitus, cardiovascular disease, and cancer. For rapid control of energy homeostasis, allosteric and posttranslational events activate or alter activity of key metabolic enzymes. For longer impact, transcriptional regulation is more effective, especially in response to nutrients such as long chain fatty acids (LCFA). Recent advances provide insights into how poorly water-soluble lipid nutrients [LCFA; retinoic acid (RA)] and their metabolites (long chain fatty acyl Coenzyme A, LCFA-CoA) reach nuclei, bind their cognate ligand-activated receptors, and regulate transcription for signaling lipid and glucose catabolism or storage: (i) while serum and cytoplasmic LCFA levels are in the 200 mircroM-mM range, real-time imaging recently revealed that LCFA and LCFA-CoA are also located within nuclei (nM range); (ii) sensitive fluorescence binding assays show that LCFA-activated nuclear receptors [peroxisome proliferator-activated receptor-alpha (PPARalpha) and hepatocyte nuclear factor 4alpha (HNF4alpha)] exhibit high affinity (low nM KdS) for LCFA (PPARalpha) and/or LCFA-CoA (PPARalpha, HNF4alpha)-in the same range as nuclear levels of these ligands; (iii) live and fixed cell immunolabeling and imaging revealed that some cytoplasmic lipid binding proteins [liver fatty acid binding protein (L-FABP), acyl CoA binding protein (ACBP), cellular retinoic acid binding protein-2 (CRABP-2)] enter nuclei, bind nuclear receptors (PPARalpha, HNF4alpha, CRABP-2), and activate transcription of genes in fatty acid and glucose metabolism; and (iv) studies with gene ablated mice provided physiological relevance of LCFA and LCFA-CoA binding proteins in nuclear signaling. This led to the hypothesis that cytoplasmic lipid binding proteins transfer and channel lipidic ligands into nuclei for initiating nuclear receptor transcriptional activity to provide new lipid nutrient signaling pathways that

  14. Targeting cytokine/chemokine receptors: a challenge for molecular nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Signore, A. [Nuclear Medicine Unit, Department of Clinical Sciences, Policlinico Umberto I, University ' ' La Sapienza' ' , Via del Policlinico 155, 00161 Roma (Italy); Chianelli, M. [Nuclear Medicine, ' ' Regina Apostolorum' ' Hospital, Albano (Roma) (Italy); Bei, R.; Modesti, A. [Department of Experimental Medicine and Biochemical Sciences, University ' ' Tor Vergata' ' , Roma (Italy); Oyen, W. [Department of Nuclear Medicine, University Medical Center, Nijmegen (Netherlands)

    2003-01-01

    Radiolabelled cytokines and chemokines are a group of radiopharmaceuticals that, by highlighting in vivo the binding to specific high-affinity receptors expressed on selected cell populations, allow the molecular and functional characterisation of immune-mediated processes Recently, several authors have described the use of radiolabelled cytokines and chemokines not only for imaging of inflammation and infection, but also as an approach to study in vivo the biology of primary and metastatic cancer cells. The latter avenue of research has been pursued particularly to help oncologists in therapeutic decision making and to follow up the efficacy of new immune therapies. In this paper we describe the characteristics of cytokines and chemokines, focussing on their role as radiopharmaceuticals for the imaging of cancer cells in vivo, a new challenge for molecular nuclear medicine. (orig.)

  15. The Role of Nuclear Receptor-Binding SET Domain Family Histone Lysine Methyltransferases in Cancer.

    Science.gov (United States)

    Bennett, Richard L; Swaroop, Alok; Troche, Catalina; Licht, Jonathan D

    2017-06-01

    The nuclear receptor-binding SET Domain (NSD) family of histone H3 lysine 36 methyltransferases is comprised of NSD1, NSD2 (MMSET/WHSC1), and NSD3 (WHSC1L1). These enzymes recognize and catalyze methylation of histone lysine marks to regulate chromatin integrity and gene expression. The growing number of reports demonstrating that alterations or translocations of these genes fundamentally affect cell growth and differentiation leading to developmental defects illustrates the importance of this family. In addition, overexpression, gain of function somatic mutations, and translocations of NSDs are associated with human cancer and can trigger cellular transformation in model systems. Here we review the functions of NSD family members and the accumulating evidence that these proteins play key roles in tumorigenesis. Because epigenetic therapy is an important emerging anticancer strategy, understanding the function of NSD family members may lead to the development of novel therapies. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  16. Loss of function of the retinoid-related nuclear receptor (RORB) gene and epilepsy

    DEFF Research Database (Denmark)

    Rudolf, Gabrielle; Lesca, Gaetan; Mehrjouy, Mana M

    2016-01-01

    nuclear receptor (RORβ), in four affected family members. In addition, two de novo variants (c.218T>C/p.(Leu73Pro); c.1249_1251delACG/p.(Thr417del)) were identified in sporadic patients by trio-based exome sequencing. We also found two de novo deletions in patients with behavioral and cognitive impairment...... in various types of epilepsies in the past few years. In the present study, we performed whole-exome sequencing in a family with GGE consistent with the diagnosis of eyelid myoclonia with absences. We found a nonsense variant (c.196C>T/p.(Arg66*)) in RORB, which encodes the beta retinoid-related orphan...

  17. TIF1alpha: a possible link between KRAB zinc finger proteins and nuclear receptors

    DEFF Research Database (Denmark)

    Le Douarin, B; You, J; Nielsen, Anders Lade

    1998-01-01

    Ligand-induced gene activation by nuclear receptors (NRs) is thought to be mediated by transcriptional intermediary factors (TIFs), that interact with their ligand-dependent AF-2 activating domain. Included in the group of the putative AF-2 TIFs identified so far is TIF1alpha, a member of a new...... family of proteins which contains an N-terminal RBCC (RING finger-B boxes-coiled coil) motif and a C-terminal bromodomain preceded by a PHD finger. In addition to these conserved domains present in a number of transcriptional regulatory proteins, TIF1alpha was found to contain several protein......-protein interaction sites. Of these, one specifically interacts with NRs bound to their agonistic ligand and not with NR mutants that are defective in the AF-2 activity. Immediately adjacent to this 'NR box', TIF1alpha contains an interaction site for members of the chromatin organization modifier (chromo) family, HP...

  18. The nuclear receptor DAF-12 regulates nutrient metabolism and reproductive growth in nematodes.

    Directory of Open Access Journals (Sweden)

    Zhu Wang

    2015-03-01

    Full Text Available Appropriate nutrient response is essential for growth and reproduction. Under favorable nutrient conditions, the C. elegans nuclear receptor DAF-12 is activated by dafachronic acids, hormones that commit larvae to reproductive growth. Here, we report that in addition to its well-studied role in controlling developmental gene expression, the DAF-12 endocrine system governs expression of a gene network that stimulates the aerobic catabolism of fatty acids. Thus, activation of the DAF-12 transcriptome coordinately mobilizes energy stores to permit reproductive growth. DAF-12 regulation of this metabolic gene network is conserved in the human parasite, Strongyloides stercoralis, and inhibition of specific steps in this network blocks reproductive growth in both of the nematodes. Our study provides a molecular understanding for metabolic adaptation of nematodes to their environment, and suggests a new therapeutic strategy for treating parasitic diseases.

  19. Feed-forward transcriptional programming by nuclear receptors: regulatory principles and therapeutic implications.

    Science.gov (United States)

    Sasse, Sarah K; Gerber, Anthony N

    2015-01-01

    Nuclear receptors (NRs) are widely targeted to treat a range of human diseases. Feed-forward loops are an ancient mechanism through which single cell organisms organize transcriptional programming and modulate gene expression dynamics, but they have not been systematically studied as a regulatory paradigm for NR-mediated transcriptional responses. Here, we provide an overview of the basic properties of feed-forward loops as predicted by mathematical models and validated experimentally in single cell organisms. We review existing evidence implicating feed-forward loops as important in controlling clinically relevant transcriptional responses to estrogens, progestins, and glucocorticoids, among other NR ligands. We propose that feed-forward transcriptional circuits are a major mechanism through which NRs integrate signals, exert temporal control over gene regulation, and compartmentalize client transcriptomes into discrete subunits. Implications for the design and function of novel selective NR ligands are discussed.

  20. Cross-regulation of protein stability by p53 and nuclear receptor SHP.

    Directory of Open Access Journals (Sweden)

    Zhihong Yang

    Full Text Available We report here a novel interplay between tumor suppressor p53 and nuclear receptor SHP that controls p53 and SHP stability. Overexpression of p53 causes rapid SHP protein degradation, which does not require the presence of Mdm2 and is mediated by the proteosome pathway. Overexpressing SHP alone does not affect p53 stability. However, SHP destabilizes p53 by augmentation of Mdm2 ubiquitin ligase activity toward p53. The single amino acid substitution in the SHP protein SHPK170R increases SHP binding to p53 relative to SHP wild-type, whereas SHPG171A variant shows a diminished p53 binding. As a result of the cross-regulation, the tumor suppressor function of p53 and SHP in inhibition of colon cancer growth is compromised. Our findings reveal a unique scenario for a cross-inhibition between two tumor suppressors to keep their expression and function in check.

  1. Site-specific proteolysis of the transcriptional coactivator HCF-1 can regulate its interaction with protein cofactors.

    Science.gov (United States)

    Vogel, Jodi L; Kristie, Thomas M

    2006-05-01

    Limited proteolytic processing is an important transcriptional regulatory mechanism. In various contexts, proteolysis controls the cytoplasmic-to-nuclear transport of important transcription factors or removes domains to produce factors with altered activities. The transcriptional coactivator host cell factor-1 (HCF-1) is proteolytically processed within a unique domain consisting of 20-aa reiterations. Site-specific cleavage within one or more repeats generates a family of amino- and carboxyl-terminal subunits that remain tightly associated. However, the consequences of HCF-1 processing have been undefined. In this study, it was determined that the HCF-1-processing domain interacts with several proteins including the transcriptional coactivator/corepressor four-and-a-half LIM domain-2 (FHL2). Analysis of this interaction has uncovered specificity with both sequence and context determinants within the reiterations of this processing domain. In cells, FHL2 interacts exclusively with the nonprocessed coactivator and costimulates transcription of an HCF-1-dependent target gene. The functional interaction of HCF-1 with FHL2 supports a model in which site-specific proteolysis regulates the interaction of HCF-1 with protein partners and thus can modulate the activity of this coactivator. This paradigm expands the biological significance of limited proteolytic processing as a regulatory mechanism in gene transcription.

  2. Role of nuclear receptor CAR in carbon tetrachloride-induced hepatotoxicity

    Institute of Scientific and Technical Information of China (English)

    Yuichi Yamazaki; Satoru Kakizaki; Norio Horiguchi; Hitoshi Takagi; Masatomo Mori; Masahiko Negishi

    2005-01-01

    AIM: To investigate the precise roles of CAR in CCl4-induced acute hepatotoxicity.METHODS: To prepare an acute liver injury model, CCl4 was intraperitoneally injected in CAR+/+ and CAR-/- mice.RESULTS: Elevation of serum alanine aminotransferase and extension of centrilobular necrosis were slightly inhibited in CAR-/- mice compared to CAR+/+ mice without PB. Administration of a CAR inducer, PB, revealed that CCl4-induced liver toxicity was partially inhibited in CAR-/- mice compared with CAR+/+ mice. On the other hand,androstanol, an inverse agonist ligand, inhibited hepatotoxicity in CAR+/+ but not in CAR-/- mice. Thus, CAR activation caused CCl4 hepatotoxicity while CAR inhibition resulted in partial protection against CCl4-induced hepatotoxicity.There were no differences in the expression of CYP2E1, the main metabolizing enzyme for CCl4, between CAR+/+ and CAR-/- mice. However, the expression of other CCl4-metabolizing enzymes, such as CYP2B10 and 3A11, was induced by PB in CAR+/+ but not in CAR-/- mice. Although the main pathway of CCl4-induced acute liver injury is mediated by CYP2E1, CAR modulates its pathway via induction of CYP2B10 and 3A11 in the presence of activator or inhibitor.CONCLUSION: The nuclear receptor CAR modulates CCl4-induced liver injury via induction of CCl4-metabolizing enzymes in the presence of an activator. Our results suggest that drugs interacting with nuclear receptors such as PB might play critical roles in drug-induced liver injury or drugdrug interaction even though such drugs themselves are not hepatotoxic.

  3. Structural Basis of Natural Promoter Recognition by a Unique Nuclear Receptor, HNF4[alpha

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Peng; Rha, Geun Bae; Melikishvili, Manana; Wu, Guangteng; Adkins, Brandon C.; Fried, Michael G.; Chi, Young-In (Kentucky)

    2010-11-09

    HNF4{alpha} (hepatocyte nuclear factor 4{alpha}) plays an essential role in the development and function of vertebrate organs, including hepatocytes and pancreatic {beta}-cells by regulating expression of multiple genes involved in organ development, nutrient transport, and diverse metabolic pathways. As such, HNF4{alpha} is a culprit gene product for a monogenic and dominantly inherited form of diabetes, known as maturity onset diabetes of the young (MODY). As a unique member of the nuclear receptor superfamily, HNF4{alpha} recognizes target genes containing two hexanucleotide direct repeat DNA-response elements separated by one base pair (DR1) by exclusively forming a cooperative homodimer. We describe here the 2.0 {angstrom} crystal structure of human HNF4{alpha} DNA binding domain in complex with a high affinity promoter element of another MODY gene, HNF1{alpha}, which reveals the molecular basis of unique target gene selection/recognition, DNA binding cooperativity, and dysfunction caused by diabetes-causing mutations. The predicted effects of MODY mutations have been tested by a set of biochemical and functional studies, which show that, in contrast to other MODY gene products, the subtle disruption of HNF4{alpha} molecular function can cause significant effects in afflicted MODY patients.

  4. Evolutionary trace-based peptides identify a novel asymmetric interaction that mediates oligomerization in nuclear receptors.

    Science.gov (United States)

    Gu, Peili; Morgan, Daniel H; Sattar, Minawar; Xu, Xueping; Wagner, Ryan; Raviscioni, Michele; Lichtarge, Olivier; Cooney, Austin J

    2005-09-01

    Germ cell nuclear factor (GCNF) is an orphan nuclear receptor that plays important roles in development and reproduction, by repressing the expression of essential genes such as Oct4, GDF9, and BMP15, through binding to DR0 elements. Surprisingly, whereas recombinant GCNF binds to DR0 sequences as a homodimer, endogenous GCNF does not exist as a homodimer but rather as part of a large complex termed the transiently retinoid-induced factor (TRIF). Here, we use evolutionary trace (ET) analysis to design mutations and peptides that probe the molecular basis for the formation of this unusual complex. We find that GCNF homodimerization and TRIF complex formation are DNA-dependent, and ET suggests that dimerization involves key functional sites on both helix 3 and helix 11, which are located on opposing surfaces of the ligand binding domain. Targeted mutations in either helix of GCNF disrupt the formation of both the homodimer and the endogenous TRIF complex. Moreover, peptide mimetics of both of these ET-determined sites inhibit dimerization and TRIF complex formation. This suggests that a novel helix 3-helix 11 heterotypic interaction mediates GCNF interaction and would facilitate oligomerization. Indeed, it was determined that the endogenous TRIF complex is composed of a GCNF oligomer. These findings shed light on an evolutionarily selected mechanism that reveals the unusual DNA-binding, dimerization, and oligomerization properties of GCNF.

  5. KPNA7, a nuclear transport receptor, promotes malignant properties of pancreatic cancer cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Laurila, Eeva; Vuorinen, Elisa [Institute of Biomedical Technology, FIN-33014 University of Tampere and BioMediTech, Biokatu 6, 33520 Tampere (Finland); Fimlab Laboratories, Biokatu 4, 33520 Tampere (Finland); Savinainen, Kimmo; Rauhala, Hanna [Institute of Biomedical Technology, FIN-33014 University of Tampere and BioMediTech, Biokatu 6, 33520 Tampere (Finland); Kallioniemi, Anne, E-mail: anne.kallioniemi@uta.fi [Institute of Biomedical Technology, FIN-33014 University of Tampere and BioMediTech, Biokatu 6, 33520 Tampere (Finland); Fimlab Laboratories, Biokatu 4, 33520 Tampere (Finland)

    2014-03-10

    Pancreatic cancer is an aggressive malignancy and one of the leading causes of cancer deaths. The high mortality rate is mostly due to the lack of appropriate tools for early detection of the disease and a shortage of effective therapies. We have previously shown that karyopherin alpha 7 (KPNA7), the newest member of the alpha karyopherin family of nuclear import receptors, is frequently amplified and overexpressed in pancreatic cancer. Here, we report that KPNA7 expression is absent in practically all normal human adult tissues but elevated in several pancreatic cancer cell lines. Inhibition of KPNA7 expression in AsPC-1 and Hs700T pancreatic cancer cells led to a reduction in cell growth and decreased anchorage independent growth, as well as increased autophagy. The cell growth effects were accompanied by an induction of the cell cycle regulator p21 and a G1 arrest of the cell cycle. Interestingly, the p21 induction was caused by increased mRNA synthesis and not defective nuclear transport. These data strongly demonstrate that KPNA7 silencing inhibits the malignant properties of pancreatic cancer cells in vitro and thereby provide the first evidence on the functional role for KPNA7 in human cancer. - Highlights: • KPNA7 expression is elevated in several pancreatic cancer cell lines. • KPNA7 silencing in high expressing cancer cells leads to growth inhibition. • The cell growth reduction is associated with p21 induction and G1 arrest. • KPNA7 silencing is also accompanied with increased autophagy.

  6. HIV-1 infection is associated with changes in nuclear receptor transcriptome, pro-inflammatory and lipid profile of monocytes

    Directory of Open Access Journals (Sweden)

    Renga Barbara

    2012-10-01

    Full Text Available Abstract Background Persistent residual immune activation and lipid dysmetabolism are characteristics of HIV positive patients receiving an highly active antiretroviral therapy (HAART. Nuclear Receptors are transcription factors involved in the regulation of immune and metabolic functions through the modulation of gene transcription. The objective of the present study was to investigate for the relative abundance of members of the nuclear receptor family in monocytic cells isolated from HIV positive patients treated or not treated with HAART. Methods Monocytes isolated from peripheral blood mononuclear cells (PBMC were used for analysis of the relative mRNA expressions of FXR, PXR, LXR, VDR, RARα, RXR, PPARα, PPARβ, PPARγ and GR by Real-Time polymerase chain reaction (PCR. The expression of a selected subset of inflammatory and metabolic genes MCP-1, ICAM-1, CD36 and ABCA1 was also measured. Results Monocytes isolated from HIV infected patients expressed an altered pattern of nuclear receptors characterized by a profound reduction in the expressions of FXR, PXR, PPARα, GR, RARα and RXR. Of interest, the deregulated expression of nuclear receptors was not restored under HAART and was linked to an altered expression of genes which supports both an immune activation and altered lipid metabolism in monocytes. Conclusions Altered expression of genes mediating reciprocal regulation of lipid metabolism and immune function in monocytes occurs in HIV. The present findings provide a mechanistic explanation for immune activation and lipid dysmetabolism occurring in HIV infected patients and could lead to the identification of novel potential therapeutic targets.

  7. HIV-1 infection is associated with changes in nuclear receptor transcriptome, pro-inflammatory and lipid profile of monocytes.

    Science.gov (United States)

    Renga, Barbara; Francisci, Daniela; D'Amore, Claudio; Schiaroli, Elisabetta; Carino, Adriana; Baldelli, Franco; Fiorucci, Stefano

    2012-10-29

    Persistent residual immune activation and lipid dysmetabolism are characteristics of HIV positive patients receiving an highly active antiretroviral therapy (HAART). Nuclear Receptors are transcription factors involved in the regulation of immune and metabolic functions through the modulation of gene transcription. The objective of the present study was to investigate for the relative abundance of members of the nuclear receptor family in monocytic cells isolated from HIV positive patients treated or not treated with HAART. Monocytes isolated from peripheral blood mononuclear cells (PBMC) were used for analysis of the relative mRNA expressions of FXR, PXR, LXR, VDR, RARα, RXR, PPARα, PPARβ, PPARγ and GR by Real-Time polymerase chain reaction (PCR). The expression of a selected subset of inflammatory and metabolic genes MCP-1, ICAM-1, CD36 and ABCA1 was also measured. Monocytes isolated from HIV infected patients expressed an altered pattern of nuclear receptors characterized by a profound reduction in the expressions of FXR, PXR, PPARα, GR, RARα and RXR. Of interest, the deregulated expression of nuclear receptors was not restored under HAART and was linked to an altered expression of genes which supports both an immune activation and altered lipid metabolism in monocytes. Altered expression of genes mediating reciprocal regulation of lipid metabolism and immune function in monocytes occurs in HIV. The present findings provide a mechanistic explanation for immune activation and lipid dysmetabolism occurring in HIV infected patients and could lead to the identification of novel potential therapeutic targets.

  8. The phosphatidylserine receptor from Hydra is a nuclear protein with potential Fe(II dependent oxygenase activity

    Directory of Open Access Journals (Sweden)

    Stiening Beate

    2004-06-01

    Full Text Available Abstract Background Apoptotic cell death plays an essential part in embryogenesis, development and maintenance of tissue homeostasis in metazoan animals. The culmination of apoptosis in vivo is the phagocytosis of cellular corpses. One morphological characteristic of cells undergoing apoptosis is loss of plasma membrane phospholipid asymmetry and exposure of phosphatidylserine on the outer leaflet. Surface exposure of phosphatidylserine is recognised by a specific receptor (phosphatidylserine receptor, PSR and is required for phagocytosis of apoptotic cells by macrophages and fibroblasts. Results We have cloned the PSR receptor from Hydra in order to investigate its function in this early metazoan. Bioinformatic analysis of the Hydra PSR protein structure revealed the presence of three nuclear localisation signals, an AT-hook like DNA binding motif and a putative 2-oxoglutarate (2OG-and Fe(II-dependent oxygenase activity. All of these features are conserved from human PSR to Hydra PSR. Expression of GFP tagged Hydra PSR in hydra cells revealed clear nuclear localisation. Deletion of one of the three NLS sequences strongly diminished nuclear localisation of the protein. Membrane localisation was never detected. Conclusions Our results suggest that Hydra PSR is a nuclear 2-oxoglutarate (2OG-and Fe(II-dependent oxygenase. This is in contrast with the proposed function of Hydra PSR as a cell surface receptor involved in the recognition of apoptotic cells displaying phosphatidylserine on their surface. The conservation of the protein from Hydra to human infers that our results also apply to PSR from higher animals.

  9. Nuclear Receptor Expression Defines a Set of Prognostic Biomarkers for Lung Cancer

    Science.gov (United States)

    Xiao, Guanghua; Behrens, Carmen; Girard, Luc; Wistuba, Ignacio I.; Minna, John D.; Mangelsdorf, David J.

    2010-01-01

    Background The identification of prognostic tumor biomarkers that also would have potential as therapeutic targets, particularly in patients with early stage disease, has been a long sought-after goal in the management and treatment of lung cancer. The nuclear receptor (NR) superfamily, which is composed of 48 transcription factors that govern complex physiologic and pathophysiologic processes, could represent a unique subset of these biomarkers. In fact, many members of this family are the targets of already identified selective receptor modulators, providing a direct link between individual tumor NR quantitation and selection of therapy. The goal of this study, which begins this overall strategy, was to investigate the association between mRNA expression of the NR superfamily and the clinical outcome for patients with lung cancer, and to test whether a tumor NR gene signature provided useful information (over available clinical data) for patients with lung cancer. Methods and Findings Using quantitative real-time PCR to study NR expression in 30 microdissected non-small-cell lung cancers (NSCLCs) and their pair-matched normal lung epithelium, we found great variability in NR expression among patients' tumor and non-involved lung epithelium, found a strong association between NR expression and clinical outcome, and identified an NR gene signature from both normal and tumor tissues that predicted patient survival time and disease recurrence. The NR signature derived from the initial 30 NSCLC samples was validated in two independent microarray datasets derived from 442 and 117 resected lung adenocarcinomas. The NR gene signature was also validated in 130 squamous cell carcinomas. The prognostic signature in tumors could be distilled to expression of two NRs, short heterodimer partner and progesterone receptor, as single gene predictors of NSCLC patient survival time, including for patients with stage I disease. Of equal interest, the studies of microdissected

  10. The nuclear receptor DHR3 modulates dS6 kinase-dependent growth in Drosophila.

    Science.gov (United States)

    Montagne, Jacques; Lecerf, Caroline; Parvy, Jean-Philippe; Bennion, Janis M; Radimerski, Thomas; Ruhf, Marie-Laure; Zilbermann, Frederic; Vouilloz, Nicole; Stocker, Hugo; Hafen, Ernst; Kozma, Sara C; Thomas, George

    2010-05-06

    S6 kinases (S6Ks) act to integrate nutrient and insulin signaling pathways and, as such, function as positive effectors in cell growth and organismal development. However, they also have been shown to play a key role in limiting insulin signaling and in mediating the autophagic response. To identify novel regulators of S6K signaling, we have used a Drosophila-based, sensitized, gain-of-function genetic screen. Unexpectedly, one of the strongest enhancers to emerge from this screen was the nuclear receptor (NR), Drosophila hormone receptor 3 (DHR3), a critical constituent in the coordination of Drosophila metamorphosis. Here we demonstrate that DHR3, through dS6K, also acts to regulate cell-autonomous growth. Moreover, we show that the ligand-binding domain (LBD) of DHR3 is essential for mediating this response. Consistent with these findings, we have identified an endogenous DHR3 isoform that lacks the DBD. These results provide the first molecular link between the dS6K pathway, critical in controlling nutrient-dependent growth, and that of DHR3, a major mediator of ecdysone signaling, which, acting together, coordinate metamorphosis.

  11. The nuclear receptor DHR3 modulates dS6 kinase-dependent growth in Drosophila.

    Directory of Open Access Journals (Sweden)

    Jacques Montagne

    2010-05-01

    Full Text Available S6 kinases (S6Ks act to integrate nutrient and insulin signaling pathways and, as such, function as positive effectors in cell growth and organismal development. However, they also have been shown to play a key role in limiting insulin signaling and in mediating the autophagic response. To identify novel regulators of S6K signaling, we have used a Drosophila-based, sensitized, gain-of-function genetic screen. Unexpectedly, one of the strongest enhancers to emerge from this screen was the nuclear receptor (NR, Drosophila hormone receptor 3 (DHR3, a critical constituent in the coordination of Drosophila metamorphosis. Here we demonstrate that DHR3, through dS6K, also acts to regulate cell-autonomous growth. Moreover, we show that the ligand-binding domain (LBD of DHR3 is essential for mediating this response. Consistent with these findings, we have identified an endogenous DHR3 isoform that lacks the DBD. These results provide the first molecular link between the dS6K pathway, critical in controlling nutrient-dependent growth, and that of DHR3, a major mediator of ecdysone signaling, which, acting together, coordinate metamorphosis.

  12. The epoxygenases CYP2J2 activates the nuclear receptor PPARalpha in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Jessica A Wray

    Full Text Available BACKGROUND: Peroxisome proliferator-activated receptors (PPARs are a family of three (PPARalpha, -beta/delta, and -gamma nuclear receptors. In particular, PPARalpha is involved in regulation of fatty acid metabolism, cell growth and inflammation. PPARalpha mediates the cardiac fasting response, increasing fatty acid metabolism, decreasing glucose utilisation, and is the target for the fibrate lipid-lowering class of drugs. However, little is known regarding the endogenous generation of PPAR ligands. CYP2J2 is a lipid metabolising cytochrome P450, which produces anti-inflammatory mediators, and is considered the major epoxygenase in the human heart. METHODOLOGY/PRINCIPAL FINDINGS: Expression of CYP2J2 in vitro results in an activation of PPAR responses with a particular preference for PPARalpha. The CYP2J2 products 8,9- and 11-12-EET also activate PPARalpha. In vitro, PPARalpha activation by its selective ligand induces the PPARalpha target gene pyruvate dehydrogenase kinase (PDK4 in cardiac tissue. In vivo, in cardiac-specific CYP2J2 transgenic mice, fasting selectively augments the expression of PDK4. CONCLUSIONS/SIGNIFICANCE: Our results establish that CYP2J2 produces PPARalpha ligands in vitro and in vivo, and suggests that lipid metabolising CYPs are prime candidates for the integration of global lipid changes to transcriptional signalling events.

  13. Non-nuclear-initiated actions of the estrogen receptor protect cortical bone mass.

    Science.gov (United States)

    Bartell, Shoshana M; Han, Li; Kim, Ha-neui; Kim, Sung Hoon; Katzenellenbogen, John A; Katzenellenbogen, Benita S; Chambliss, Ken L; Shaul, Philip W; Roberson, Paula K; Weinstein, Robert S; Jilka, Robert L; Almeida, Maria; Manolagas, Stavros C

    2013-04-01

    Extensive evidence has suggested that at least some of the effects of estrogens on bone are mediated via extranuclear estrogen receptor α signaling. However, definitive proof for this contention and the extent to which such effects may contribute to the overall protective effects of estrogens on bone maintenance have remained elusive. Here, we investigated the ability of a 17β-estradiol (E2) dendrimer conjugate (EDC), incapable of stimulating nuclear-initiated actions of estrogen receptor α, to prevent the effects of ovariectomy (OVX) on the murine skeleton. We report that EDC was as potent as an equimolar dose of E2 in preventing bone loss in the cortical compartment that represents 80% of the entire skeleton, but was ineffective on cancellous bone. In contrast, E2 was effective in both compartments. Consistent with its effect on cortical bone mass, EDC partially prevented the loss of both vertebral and femoral strength. In addition, EDC, as did E2, prevented the OVX-induced increase in osteoclastogenesis, osteoblastogenesis, and oxidative stress. Nonetheless, the OVX-induced decrease in uterine weight was unaltered by EDC but was restored by E2. These results demonstrate that the protection of cortical bone mass by estrogens is mediated, at least in part, via a mechanism that is distinct from the classic mechanism of estrogen action on reproductive organs.

  14. Membrane and integrative nuclear fibroblastic growth factor receptor (FGFR) regulation of FGF-23.

    Science.gov (United States)

    Han, Xiaobin; Xiao, Zhousheng; Quarles, L Darryl

    2015-04-17

    Fibroblastic growth factor receptor 1 (FGFR1) signaling pathways are implicated in the regulation of FGF-23 gene transcription, but the molecular pathways remain poorly defined. We used low molecular weight (LMW, 18 kDa) FGF-2 and high molecular weight (HMW) FGF-2 isoforms, which, respectively, activate cell surface FGF receptors and intranuclear FGFR1, to determine the roles of membrane FGFRs and integrative nuclear FGFR1 signaling (INFS) in the regulation of FGF-23 gene transcription in osteoblasts. We found that LMW-FGF-2 induced NFAT and Ets1 binding to conserved cis-elements in the proximal FGF-23 promoter and stimulated FGF-23 promoter activity through PLCγ/calcineurin/NFAT and MAPK pathways in SaOS-2 and MC3T3-E1 osteoblasts. In contrast, HMW-FGF-2 stimulated FGF-23 promoter activity in osteoblasts through a cAMP-dependent binding of FGFR1 and cAMP-response element-binding protein (CREB) to a conserved cAMP response element (CRE) contiguous with the NFAT binding site in the FGF-23 promoter. Mutagenesis of the NFAT and CRE binding sites, respectively, inhibited the effects of LMW-FGF-2 and HMW-FGF-23 to stimulate FGF-23 promoter activity. FGF-2 activation of both membrane FGFRs and INFS-dependent FGFR1 pathways may provide a means to integrate systemic and local regulation of FGF-23 transcription under diverse physiological and pathological conditions.

  15. Gold-nanoparticle-based assay for instantaneous detection of nuclear hormone receptor-response elements interactions.

    Science.gov (United States)

    Tan, Yen Nee; Su, Xiaodi; Liu, Edison T; Thomsen, Jane S

    2010-04-01

    Gold nanoparticles (AuNPs) are widely used as colorimetric probes for biosensing, relying on their unique particle size-dependent and/or interparticle distance-dependent extinction spectrum and solution color. Herein, we describe an AuNP-based colorimetric assay to detect binding interactions between nuclear hormone receptors and their corresponding DNA-binding elements, particularly the human estrogen receptors (ERalpha and ERbeta) and their cognate estrogen response elements (EREs). We found that the protein-DNA (ER-ERE) complexes can stabilize citrate anion-capped AuNPs against salt-induced aggregation to a larger extent than the protein (ER) or the DNA (ERE) alone, due to their unique molecular size and charge properties that provide a strong electrosteric protection. Moreover, our results show that the extent of stabilization is sequence-dependent and can distinguish a single base variation in the ERE associated with minor changes in protein-DNA binding affinity. With this assay, many important parameters of protein-DNA binding events (e.g., sequence selectivity, distinct DNA binding properties of protein subtypes, binding stoichiometry, and sequence-independent transient binding) can be determined instantly without using labels, tedious sample preparations, and sophisticated instrumentation. These benefits, in particular the high-throughput potential, could enable this assay to become the assay of choice to complement conventional techniques for large scale characterization of protein-DNA interactions, a key aspect in biological research.

  16. Unexpected novel relational links uncovered by extensive developmental profiling of nuclear receptor expression.

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    Stéphanie Bertrand

    2007-11-01

    Full Text Available Nuclear receptors (NRs are transcription factors that are implicated in several biological processes such as embryonic development, homeostasis, and metabolic diseases. To study the role of NRs in development, it is critically important to know when and where individual genes are expressed. Although systematic expression studies using reverse transcriptase PCR and/or DNA microarrays have been performed in classical model systems such as Drosophila and mouse, no systematic atlas describing NR involvement during embryonic development on a global scale has been assembled. Adopting a systems biology approach, we conducted a systematic analysis of the dynamic spatiotemporal expression of all NR genes as well as their main transcriptional coregulators during zebrafish development (101 genes using whole-mount in situ hybridization. This extensive dataset establishes overlapping expression patterns among NRs and coregulators, indicating hierarchical transcriptional networks. This complete developmental profiling provides an unprecedented examination of expression of NRs during embryogenesis, uncovering their potential function during central nervous system and retina formation. Moreover, our study reveals that tissue specificity of hormone action is conferred more by the receptors than by their coregulators. Finally, further evolutionary analyses of this global resource led us to propose that neofunctionalization of duplicated genes occurs at the levels of both protein sequence and RNA expression patterns. Altogether, this expression database of NRs provides novel routes for leading investigation into the biological function of each individual NR as well as for the study of their combinatorial regulatory circuitry within the superfamily.

  17. Unexpected novel relational links uncovered by extensive developmental profiling of nuclear receptor expression.

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    Stéphanie Bertrand

    2007-11-01

    Full Text Available Nuclear receptors (NRs are transcription factors that are implicated in several biological processes such as embryonic development, homeostasis, and metabolic diseases. To study the role of NRs in development, it is critically important to know when and where individual genes are expressed. Although systematic expression studies using reverse transcriptase PCR and/or DNA microarrays have been performed in classical model systems such as Drosophila and mouse, no systematic atlas describing NR involvement during embryonic development on a global scale has been assembled. Adopting a systems biology approach, we conducted a systematic analysis of the dynamic spatiotemporal expression of all NR genes as well as their main transcriptional coregulators during zebrafish development (101 genes using whole-mount in situ hybridization. This extensive dataset establishes overlapping expression patterns among NRs and coregulators, indicating hierarchical transcriptional networks. This complete developmental profiling provides an unprecedented examination of expression of NRs during embryogenesis, uncovering their potential function during central nervous system and retina formation. Moreover, our study reveals that tissue specificity of hormone action is conferred more by the receptors than by their coregulators. Finally, further evolutionary analyses of this global resource led us to propose that neofunctionalization of duplicated genes occurs at the levels of both protein sequence and RNA expression patterns. Altogether, this expression database of NRs provides novel routes for leading investigation into the biological function of each individual NR as well as for the study of their combinatorial regulatory circuitry within the superfamily.

  18. Prospects of Targeting the Gastrin Releasing Peptide Receptor and Somatostatin Receptor 2 for Nuclear Imaging and Therapy in Metastatic Breast Cancer

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    Dalm, Simone U.; Schrijver, Willemijne A. M. E.; Sieuwerts, Anieta M.; Look, Maxime P.; Ziel - van der Made, Angelique C. J.; de Weerd, Vanja; Martens, John W.; van Diest, Paul J.; de Jong, Marion; van Deurzen, Carolien H. M.

    2017-01-01

    Background The gastrin releasing peptide receptor (GRPR) and the somatostatin receptor 2 (SSTR2) are overexpressed on primary breast cancer (BC), making them ideal candidates for receptor-mediated nuclear imaging and therapy. The aim of this study was to determine whether these receptors are also suitable targets for metastatic BC. Methods mRNA expression of human BC samples were studied by in vitro autoradiography and associated with radioligand binding. Next, GRPR and SSTR2 mRNA levels of 60 paired primary BCs and metastases from different sites were measured by quantitative reverse transcriptase polymerase chain reaction. Receptor mRNA expression levels were associated with clinico-pathological factors and expression levels of primary tumors and corresponding metastases were compared. Results Binding of GRPR and SSTR radioligands to tumor tissue correlated significantly with receptor mRNA expression. High GRPR and SSTR2 mRNA levels were associated with estrogen receptor (ESR1)-positive tumors (p<0.001 for both receptors). There was no significant difference in GRPR mRNA expression of primary tumors versus paired metastases. Regarding SSTR2 mRNA expression, there was also no significant difference in the majority of cases, apart from liver and ovarian metastases which showed a significantly lower expression compared to the corresponding primary tumors (p = 0.02 and p = 0.03, respectively). Conclusion Targeting the GRPR and SSTR2 for nuclear imaging and/or treatment has the potential to improve BC care in primary as well as metastatic disease. PMID:28107508

  19. ONRLDB--manually curated database of experimentally validated ligands for orphan nuclear receptors: insights into new drug discovery.

    Science.gov (United States)

    Nanduri, Ravikanth; Bhutani, Isha; Somavarapu, Arun Kumar; Mahajan, Sahil; Parkesh, Raman; Gupta, Pawan

    2015-01-01

    Orphan nuclear receptors are potential therapeutic targets. The Orphan Nuclear Receptor Ligand Binding Database (ONRLDB) is an interactive, comprehensive and manually curated database of small molecule ligands targeting orphan nuclear receptors. Currently, ONRLDB consists of ∼11,000 ligands, of which ∼6500 are unique. All entries include information for the ligand, such as EC50 and IC50, number of aromatic rings and rotatable bonds, XlogP, hydrogen donor and acceptor count, molecular weight (MW) and structure. ONRLDB is a cross-platform database, where either the cognate small molecule modulators of a receptor or the cognate receptors to a ligand can be searched. The database can be searched using three methods: text search, advanced search or similarity search. Substructure search, cataloguing tools, and clustering tools can be used to perform advanced analysis of the ligand based on chemical similarity fingerprints, hierarchical clustering, binning partition and multidimensional scaling. These tools, together with the Tree function provided, deliver an interactive platform and a comprehensive resource for identification of common and unique scaffolds. As demonstrated, ONRLDB is designed to allow selection of ligands based on various properties and for designing novel ligands or to improve the existing ones. Database URL: http://www.onrldb.org/.

  20. Mechanism of CREB recognition and coactivation by the CREB-regulated transcriptional coactivator CRTC2.

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    Luo, Qianyi; Viste, Kristin; Urday-Zaa, Janny Concha; Senthil Kumar, Ganesan; Tsai, Wen-Wei; Talai, Afsaneh; Mayo, Kelly E; Montminy, Marc; Radhakrishnan, Ishwar

    2012-12-18

    Basic leucine zipper (bZip) transcription factors regulate cellular gene expression in response to a variety of extracellular signals and nutrient cues. Although the bZip domain is widely known to play significant roles in DNA binding and dimerization, recent studies point to an additional role for this motif in the recruitment of the transcriptional apparatus. For example, the cAMP response element binding protein (CREB)-regulated transcriptional coactivator (CRTC) family of transcriptional coactivators has been proposed to promote the expression of calcium and cAMP responsive genes, by binding to the CREB bZip in response to extracellular signals. Here we show that the CREB-binding domain (CBD) of CRTC2 folds into a single isolated 28-residue helix that seems to be critical for its interaction with the CREB bZip. The interaction is of micromolar affinity on palindromic and variant half-site cAMP response elements (CREs). The CBD and CREB assemble on the CRE with 2:2:1 stoichiometry, consistent with the presence of one CRTC binding site on each CREB monomer. Indeed, the CBD helix and the solvent-exposed residues in the dimeric CREB bZip coiled-coil form an extended protein-protein interface. Because mutation of relevant bZip residues in this interface disrupts the CRTC interaction without affecting DNA binding, our results illustrate that distinct DNA binding and transactivation functions are encoded within the structural constraints of a canonical bZip domain.

  1. TBLR1 regulates the expression of nuclear hormone receptor co-repressors

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    Brown Stuart

    2006-08-01

    Full Text Available Abstract Background Transcription is regulated by a complex interaction of activators and repressors. The effectors of repression are large multimeric complexes which contain both the repressor proteins that bind to transcription factors and a number of co-repressors that actually mediate transcriptional silencing either by inhibiting the basal transcription machinery or by recruiting chromatin-modifying enzymes. Results TBLR1 [GenBank: NM024665] is a co-repressor of nuclear hormone transcription factors. A single highly conserved gene encodes a small family of protein molecules. Different isoforms are produced by differential exon utilization. Although the ORF of the predominant form contains only 1545 bp, the human gene occupies ~200 kb of genomic DNA on chromosome 3q and contains 16 exons. The genomic sequence overlaps with the putative DC42 [GenBank: NM030921] locus. The murine homologue is structurally similar and is also located on Chromosome 3. TBLR1 is closely related (79% homology at the mRNA level to TBL1X and TBL1Y, which are located on Chromosomes X and Y. The expression of TBLR1 overlaps but is distinct from that of TBL1. An alternatively spliced form of TBLR1 has been demonstrated in human material and it too has an unique pattern of expression. TBLR1 and the homologous genes interact with proteins that regulate the nuclear hormone receptor family of transcription factors. In resting cells TBLR1 is primarily cytoplasmic but after perturbation the protein translocates to the nucleus. TBLR1 co-precipitates with SMRT, a co-repressor of nuclear hormone receptors, and co-precipitates in complexes immunoprecipitated by antiserum to HDAC3. Cells engineered to over express either TBLR1 or N- and C-terminal deletion variants, have elevated levels of endogenous N-CoR. Co-transfection of TBLR1 and SMRT results in increased expression of SMRT. This co-repressor undergoes ubiquitin-mediated degradation and we suggest that the stabilization of

  2. p35 regulates the CRM1-dependent nucleocytoplasmic shuttling of nuclear hormone receptor coregulator-interacting factor 1 (NIF-1.

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    Xiao-Su Zhao

    Full Text Available Cyclin-dependent kinase 5 (Cdk5 is a proline-directed serine/threonine kinase, which plays critical roles in a wide spectrum of neuronal functions including neuronal survival, neurite outgrowth, and synapse development and plasticity. Cdk5 activity is controlled by its specific activators: p35 or p39. While knockout studies reveal that Cdk5/p35 is critical for neuronal migration during early brain development, functions of Cdk5/p35 have been unraveled through the identification of the interacting proteins of p35, most of which are Cdk5/p35 substrates. However, it remains unclear whether p35 can regulate neuronal functions independent of Cdk5 activity. Here, we report that a nuclear protein, nuclear hormone receptor coregulator (NRC-interacting factor 1 (NIF-1, is a new interacting partner of p35. Interestingly, p35 regulates the functions of NIF-1 independent of Cdk5 activity. NIF-1 was initially discovered as a transcriptional regulator that enhances the transcriptional activity of nuclear hormone receptors. Our results show that p35 interacts with NIF-1 and regulates its nucleocytoplasmic trafficking via the nuclear export pathway. Furthermore, we identified a nuclear export signal on p35; mutation of this site or blockade of the CRM1/exportin-dependent nuclear export pathway resulted in the nuclear accumulation of p35. Intriguingly, blocking the nuclear export of p35 attenuated the nuclear accumulation of NIF-1. These findings reveal a new p35-dependent mechanism in transcriptional regulation that involves the nucleocytoplasmic shuttling of transcription regulators.

  3. p35 regulates the CRM1-dependent nucleocytoplasmic shuttling of nuclear hormone receptor coregulator-interacting factor 1 (NIF-1).

    Science.gov (United States)

    Zhao, Xiao-Su; Fu, Wing-Yu; Chien, Winnie W Y; Li, Zhen; Fu, Amy K Y; Ip, Nancy Y

    2014-01-01

    Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine/threonine kinase, which plays critical roles in a wide spectrum of neuronal functions including neuronal survival, neurite outgrowth, and synapse development and plasticity. Cdk5 activity is controlled by its specific activators: p35 or p39. While knockout studies reveal that Cdk5/p35 is critical for neuronal migration during early brain development, functions of Cdk5/p35 have been unraveled through the identification of the interacting proteins of p35, most of which are Cdk5/p35 substrates. However, it remains unclear whether p35 can regulate neuronal functions independent of Cdk5 activity. Here, we report that a nuclear protein, nuclear hormone receptor coregulator (NRC)-interacting factor 1 (NIF-1), is a new interacting partner of p35. Interestingly, p35 regulates the functions of NIF-1 independent of Cdk5 activity. NIF-1 was initially discovered as a transcriptional regulator that enhances the transcriptional activity of nuclear hormone receptors. Our results show that p35 interacts with NIF-1 and regulates its nucleocytoplasmic trafficking via the nuclear export pathway. Furthermore, we identified a nuclear export signal on p35; mutation of this site or blockade of the CRM1/exportin-dependent nuclear export pathway resulted in the nuclear accumulation of p35. Intriguingly, blocking the nuclear export of p35 attenuated the nuclear accumulation of NIF-1. These findings reveal a new p35-dependent mechanism in transcriptional regulation that involves the nucleocytoplasmic shuttling of transcription regulators.

  4. The molecular mechanism of bisphenol A (BPA as an endocrine disruptor by interacting with nuclear receptors: insights from molecular dynamics (MD simulations.

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    Lanlan Li

    Full Text Available Bisphenol A (BPA can interact with nuclear receptors and affect the normal function of nuclear receptors in very low doses, which causes BPA to be one of the most controversial endocrine disruptors. However, the detailed molecular mechanism about how BPA interferes the normal function of nuclear receptors is still undiscovered. Herein, molecular dynamics simulations were performed to explore the detailed interaction mechanism between BPA with three typical nuclear receptors, including hERα, hERRγ and hPPARγ. The simulation results and calculated binding free energies indicate that BPA can bind to these three nuclear receptors. The binding affinities of BPA were slightly lower than that of E2 to these three receptors. The simulation results proved that the binding process was mainly driven by direct hydrogen bond and hydrophobic interactions. In addition, structural analysis suggested that BPA could interact with these nuclear receptors by mimicking the action of natural hormone and keeping the nuclear receptors in active conformations. The present work provided the structural evidence to recognize BPA as an endocrine disruptor and would be important guidance for seeking safer substitutions of BPA.

  5. Rapid Nongenomic Glucocorticoid Actions in Male Mouse Hypothalamic Neuroendocrine Cells Are Dependent on the Nuclear Glucocorticoid Receptor

    Science.gov (United States)

    Nahar, Jebun; Haam, Juhee; Chen, Chun; Jiang, Zhiying; Glatzer, Nicholas R.; Muglia, Louis J.; Dohanich, Gary P.; Herman, James P.

    2015-01-01

    Corticosteroids act classically via cognate nuclear receptors to regulate gene transcription; however, increasing evidence supports rapid, nontranscriptional corticosteroid actions via activation of membrane receptors. Using whole-cell patch clamp recordings in hypothalamic slices from male mouse genetic models, we tested for nongenomic glucocorticoid actions at glutamate and gamma aminobutyric acid (GABA) synapses in hypothalamic neuroendocrine cells, and for their dependence on the nuclear glucocorticoid receptor (GR). In enhanced green fluorescent protein-expressing CRH neurons of the paraventricular nucleus (PVN) and in magnocellular neurons of the PVN and supraoptic nucleus (SON), dexamethasone activated postsynaptic membrane-associated receptors and G protein signaling to elicit a rapid suppression of excitatory postsynaptic inputs, which was blocked by genetic deletion of type I cannabinoid receptors and a type I cannabinoid receptor antagonist. In magnocellular neurons, dexamethasone also elicited a rapid nitric oxide-dependent increase in inhibitory postsynaptic inputs. These data indicate a rapid, synapse-specific glucocorticoid-induced retrograde endocannabinoid signaling at glutamate synapses and nitric oxide signaling at GABA synapses. Unexpectedly, the rapid glucocorticoid effects on both excitatory and inhibitory synaptic transmission were lost with conditional deletion of GR in the PVN and SON in slices from a single minded-1-cre-directed conditional GR knockout mouse. Thus, the nongenomic glucocorticoid actions at glutamate and GABA synapses on PVN and SON neuroendocrine cells are dependent on the nuclear GR. The nuclear GR, therefore, is responsible for transducing the rapid steroid response at the membrane, or is either a critical component in the signaling cascade or regulates a critical component of the signaling cascade of a distinct membrane GR. PMID:26061727

  6. The cytoplasmic nuclear receptor RARγ controls RIP1 initiated cell death when cIAP activity is inhibited.

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    Xu, Qing; Jitkaew, Siriporn; Choksi, Swati; Kadigamuwa, Chamila; Qu, Jianhui; Choe, Moran; Jang, Jonathan; Liu, Chengyu; Liu, Zheng-Gang

    2017-09-04

    Tumor necrosis factor (TNF) has a critical role in diverse cellular events including inflammation, apoptosis and necroptosis through different signaling complexes. However, little is known about how the transition from inflammatory signaling to the engagement of death pathways is modulated. Here we report that the cytoplasmic retinoic acid receptor gamma (RARγ) controls receptor-interacting protein kinase 1 (RIP1)-initiated cell death when cellular inhibitor of apoptosis (cIAP) activity is blocked. Through screening a short hairpin RNA library, we found that RARγ was essential for TNF-induced RIP1-initiated apoptosis and necroptosis. Our data suggests that RARγ initiates the formation of death signaling complexes by mediating RIP1 dissociation from TNF receptor 1. We demonstrate that RARγ is released from the nucleus to orchestrate the formation of the cytosolic death complexes. In addition, we demonstrate that RARγ has a similar role in TNF-induced necroptosis in vivo. Thus, our study suggests that nuclear receptor RARγ provides a key checkpoint for the transition from life to death.The molecular switch between how tumour necrosis factor (TNF) controls inflammation versus cell death is less well defined. Here, the authors show that the nuclear receptor retinoic acid receptor gamma is released from the nucleus to disrupt TNF initiated cell death complexes in the cytoplasm.

  7. Sumoylation of poly(ADP-ribose) polymerase 1 inhibits its acetylation and restrains transcriptional coactivator function.

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    Messner, Simon; Schuermann, David; Altmeyer, Matthias; Kassner, Ingrid; Schmidt, Darja; Schär, Primo; Müller, Stefan; Hottiger, Michael O

    2009-11-01

    Poly(ADP-ribose) polymerase 1 (PARP1) is a chromatin-associated nuclear protein and functions as a molecular stress sensor. At the cellular level, PARP1 has been implicated in a wide range of processes, such as maintenance of genome stability, cell death, and transcription. PARP1 functions as a transcriptional coactivator of nuclear factor kappaB (NF-kappaB) and hypoxia inducible factor 1 (HIF1). In proteomic studies, PARP1 was found to be modified by small ubiquitin-like modifiers (SUMOs). Here, we characterize PARP1 as a substrate for modification by SUMO1 and SUMO3, both in vitro and in vivo. PARP1 is sumoylated at the single lysine residue K486 within its automodification domain. Interestingly, modification of PARP1 with SUMO does not affect its ADP-ribosylation activity but completely abrogates p300-mediated acetylation of PARP1, revealing an intriguing crosstalk of sumoylation and acetylation on PARP1. Genetic complementation of PARP1-depleted cells with wild-type and sumoylation-deficient PARP1 revealed that SUMO modification of PARP1 restrains its transcriptional coactivator function and subsequently reduces gene expression of distinct PARP1-regulated target genes.

  8. Genomewide comparison of the inducible transcriptomes of nuclear receptors CAR, PXR and PPARα in primary human hepatocytes.

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    Kandel, Benjamin A; Thomas, Maria; Winter, Stefan; Damm, Georg; Seehofer, Daniel; Burk, Oliver; Schwab, Matthias; Zanger, Ulrich M

    2016-09-01

    The ligand-activated nuclear receptor pregnane X receptor (PXR, NR1I2) and the constitutive androstane receptor (CAR, NR1I3) are two master transcriptional regulators of many important drug metabolizing enzymes and transporter genes (DMET) in response to xenobiotics including many drugs. The peroxisome proliferator-activated receptor alpha (PPARα, NR1C1), the target of lipid lowering fibrate drugs, primarily regulates fatty acid catabolism and energy-homeostasis. Recent research has shown that there are substantial overlaps in the regulated genes of these receptors. For example, both CAR and PXR also modulate the transcription of key enzymes involved in lipid and glucose metabolism and PPARα also functions as a direct transcriptional regulator of important DMET genes including cytochrome P450s CYP3A4 and CYP2C8. Despite their important and widespread influence on liver metabolism, comparative data are scarce, particularly at a global level and in humans. The major objective of this study was to directly compare the genome-wide transcriptional changes elucidated by the activation of these three nuclear receptors in primary human hepatocytes. Cultures from six individual donors were treated with the prototypical ligands for CAR (CITCO), PXR (rifampicin) and PPARα (WY14,643) or DMSO as vehicle control. Genomewide mRNA profiles determined with Affymetrix microarrays were analyzed for differentially expressed genes and metabolic functions. The results confirmed known prototype target genes and revealed strongly overlapping sets of coregulated but also distinctly regulated and novel responsive genes and pathways. The results further specify the role of PPARα as a regulator of drug metabolism and the role of the xenosensors PXR and CAR in lipid metabolism and energy homeostasis. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.

  9. Crystallographic Analysis of Murine Constitutive Androstane Receptor Ligand-Binding Domain Complexed with 5[alpha]-androst-16-en-3[alpha]-ol

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    Vincent, J.; Shan, L.; Fan, M.; Brunzelle, J.S.; Forman, B.M.; Fernandez, E.J. (Tennessee-K); (NWU); (CHNMC)

    2010-03-08

    The constitutive androstane receptor (CAR) is a member of the nuclear receptor superfamily. In contrast to classical nuclear receptors, which possess small-molecule ligand-inducible activity, CAR exhibits constitutive transcriptional activity in the apparent absence of ligand. CAR is among the most important transcription factors; it coordinately regulates the expression of microsomal cytochrome P450 genes and other drug-metabolizing enzymes. The murine CAR ligand-binding domain (LBD) was coexpressed with the steroid receptor coactivator protein (SRC-1) receptor-interacting domain (RID) in Escherichia coli. The mCAR LBD subunit was purified away from SRC-1 by affinity, anion-exchange and size-exclusion chromatography, crystallized with androstenol and the structure of the complex determined by molecular replacement.

  10. Nuclear translocation of cysteinyl leukotriene receptor 1 is involved in oxygen-glucose deprivation-induced damage to endothelial cells

    Institute of Scientific and Technical Information of China (English)

    San-hua FANG; Ka-na LIN; Xue-qin HUANG; Yun-bi LU; Wei-ping ZHANG; Er-qing WEI

    2012-01-01

    Aim: Cysteinyl leukotriene receptor 1 (CysLT1 receptor) is located in epithelial cells,and translocates from the plasma membrane to the nucleus in a ligand-dependent manner.Here,we investigated whether CysLT1 receptors translocated to the nucleus in endothelial cells after ischemic insult in vitro and whether it was involved in ischemic injury to endothelial cells.Methods: EA.hy926 cell line,derived from human umbilical vein endothelial cells,was subjected to oxygen-glucose deprivation (OGD).The expression and distribution of CysLT1 receptors were detected by immunofluorescent staining,immunogold labeling and immunoblotting analyses.Cell viability was evaluated using MTT reduction assay.Necrosis and apoptosis were determined by double fluorescent staining with propidium iodide and Hoechst 33342.Results: CysLT1 receptors were primarily distributed in the cytoplasm and nucleus in EA.hy926 cells,and few was found in the cell membrane.OGD induced the translocation of CysLT1 receptors from the cytoplasm to the nucleus in a time-depen dent manner,with a peak reached at 6 h.OGD-induced nuclear translocation of CysLT1 receptors was inhibited by pretreatment with the CysLT1 receptor antagonist pranlukast (10 μmol/L),or by preincubation with NLS-pep,a peptide corresponding to the nuclear localization sequence of CysLT1 receptor (10 μg/mL).However,zileuton,an inhibitor of 5-lipoxygenase that was a key enzyme in cysteinyl leukotriene generation,did not inhibit the nuclear translocation of CysLT1 receptors.Moreover,preincubation with NLS-pep (0.4 μg/mL) significantly ameliorated OGD-induced cell viability reduction and necrosis.Conclusion: CysLT1 receptors in endothelial cells translocate to the nucleus in a ligand-independent manner after ischemic insult in vitro,and it is involved in the ischemic injury.

  11. CORRELATION BETWEEN CLINICAL PATHOLOGY OF LUMINAL B BREAST CANCER AND DETERMINATION OF ESTROGEN RECEPTOR, PROGESTERONE RECEPTOR AND HER2 EXPRESSION COMBINED WITH NUCLEAR MORPHOLOGY.

    Science.gov (United States)

    Yin, D; Wang, Y L; Wang, Y F; Yang, L; Zhang, L; Tang, C; Xie, W; Ma, Y

    2015-01-01

    Breast cancer, one of the most common malignant tumors in females, draws little attention because of its untypical symptoms and signs, so the disease is usually confirmed too late, in an advanced stage. Based on the detection of nuclear morphology parameters of luminal B breast cancer, this study explored how pathological features relate to estrogen receptor (ER) and progesterone receptor (PR) expression of human epidermal growth factor receptor-2 (HER2). A quantity of 354 breast cancer specimens with follow-up records from the department of pathology in the First People’s Hospital of Nantong and the Tumor Hospital of Nantong were selected as research subjects. Nuclear parameters of specimens stained by hematoxylin and eosin were measured by imaging analysis software. It was found that breast cancer can be divided into four types, luminal B, luminal A, HER2 over-expression and basal-like type based on immunohistochemical results of three antibodies, i.e, ER, PR and HER2. A total of 113 patients (31.8%) were confirmed with luminal B breast cancer, mostly in histological stage II; the difference of nuclear morphology was of statistical significance between ER+/PR+ and ER-/PR- (Pbreast cancer, luminal B had the lowest brain metastasis rate, while HER2 over-expression subtype was found with the highest rate of lung and pleura metastasis. Besides, luminal B possessed longer disease-free survival (DFS) than basal-like (Pbreast cancer.

  12. Molecular Dynamics of "Fuzzy" Transcriptional Activator-Coactivator Interactions.

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    Natalie S Scholes

    2016-05-01

    Full Text Available Transcriptional activation domains (ADs are generally thought to be intrinsically unstructured, but capable of adopting limited secondary structure upon interaction with a coactivator surface. The indeterminate nature of this interface made it hitherto difficult to study structure/function relationships of such contacts. Here we used atomistic accelerated molecular dynamics (aMD simulations to study the conformational changes of the GCN4 AD and variants thereof, either free in solution, or bound to the GAL11 coactivator surface. We show that the AD-coactivator interactions are highly dynamic while obeying distinct rules. The data provide insights into the constant and variable aspects of orientation of ADs relative to the coactivator, changes in secondary structure and energetic contributions stabilizing the various conformers at different time points. We also demonstrate that a prediction of α-helical propensity correlates directly with the experimentally measured transactivation potential of a large set of mutagenized ADs. The link between α-helical propensity and the stimulatory activity of ADs has fundamental practical and theoretical implications concerning the recruitment of ADs to coactivators.

  13. Nuclear progesterone receptors are up-regulated by estrogens in neurons and radial glial progenitors in the brain of zebrafish.

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    Nicolas Diotel

    Full Text Available In rodents, there is increasing evidence that nuclear progesterone receptors are transiently expressed in many regions of the developing brain, notably outside the hypothalamus. This suggests that progesterone and/or its metabolites could be involved in functions not related to reproduction, particularly in neurodevelopment. In this context, the adult fish brain is of particular interest, as it exhibits constant growth and high neurogenic activity that is supported by radial glia progenitors. However, although synthesis of neuroprogestagens has been documented recently in the brain of zebrafish, information on the presence of progesterone receptors is very limited. In zebrafish, a single nuclear progesterone receptor (pgr has been cloned and characterized. Here, we demonstrate that this pgr is widely distributed in all regions of the zebrafish brain. Interestingly, we show that Pgr is strongly expressed in radial glial cells and more weakly in neurons. Finally, we present evidence, based on quantitative PCR and immunohistochemistry, that nuclear progesterone receptor mRNA and proteins are upregulated by estrogens in the brain of adult zebrafish. These data document for the first time the finding that radial glial cells are preferential targets for peripheral progestagens and/or neuroprogestagens. Given the crucial roles of radial glial cells in adult neurogenesis, the potential effects of progestagens on their activity and the fate of daughter cells require thorough investigation.

  14. Direct and Indirect Suppression of Interleukin-6 Gene Expression in Murine Macrophages by Nuclear Orphan Receptor REV-ERBα

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    Shogo Sato

    2014-01-01

    Full Text Available It is now evident that many nuclear hormone receptors can modulate target gene expression. REV-ERBα, one of the nuclear hormone receptors with the capacity to alter clock function, is critically involved in lipid metabolism, adipogenesis, and the inflammatory response. Recent studies suggest that REV-ERBα plays a key role in the mediation between clockwork and inflammation. The purpose of the current study was to investigate the role of REV-ERBα in the regulation of interleukin-6 (il6 gene expression in murine macrophages. REV-ERBα agonists, or overexpression of rev-erbα in the murine macrophage cell line RAW264 cells, suppressed the induction of il6 mRNA following a lipopolysaccharide (LPS endotoxin challenge. Also, rev-erbα overexpression decreased LPS-stimulated nuclear factor κB (NFκB activation in RAW264 cells. We showed that REV-ERBα represses il6 expression not only indirectly through an NFκB binding motif but also directly through a REV-ERBα binding motif in the murine il6 promoter region. Furthermore, peritoneal macrophages from mice lacking rev-erbα increased il6 mRNA expression. These data suggest that REV-ERBα regulates the inflammatory response of macrophages through the suppression of il6 expression. REV-ERBα may therefore be identified as a potent anti-inflammatory receptor and be a therapeutic target receptor of inflammatory diseases.

  15. Potential role of nuclear receptor ligand all-trans retinoic acids in the treatment of fungal keratitis

    Institute of Scientific and Technical Information of China (English)

    Hong-Yan; Zhou; Wei; Zhong; Hong; Zhang; Miao-Miao; Bi; Shuang; Wang; Wen-Song; Zhang

    2015-01-01

    ·Fungal keratitis(FK) is a worldwide visual impairment disease. This infectious fungus initiates the primary innate immune response and, later the adaptive immune response. The inflammatory process is related to a variety of immune cells, including macrophages, helper T cells, neutrophils, dendritic cells, and Treg cells, and is associated with proinflammatory, chemotactic and regulatory cytokines. All-trans retinoic acids(ATRA)have diverse immunomodulatory actions in a number of inflammatory and autoimmune conditions. These retinoids regulate the transcriptional levels of target genes through the activation of nuclear receptors.Retinoic acid receptor α(RAR α), retinoic acid receptor γ(RAR γ), and retinoid X receptor α(RXR α) are expressed in the cornea and immune cells. This paper summarizes new findings regarding ATRA in immune and inflammatory diseases and analyzes the perspective application of ATRA in FK.

  16. Potential role of nuclear receptor ligand all-trans retinoic acids in the treatment of fungal keratitis

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    Hong-Yan Zhou

    2015-08-01

    Full Text Available Fungal keratitis (FK is a worldwide visual impairment disease. This infectious fungus initiates the primary innate immune response and, later the adaptive immune response. The inflammatory process is related to a variety of immune cells, including macrophages, helper T cells, neutrophils, dendritic cells, and Treg cells, and is associated with proinflammatory, chemotactic and regulatory cytokines. All-trans retinoic acids (ATRA have diverse immunomodulatory actions in a number of inflammatory and autoimmune conditions. These retinoids regulate the transcriptional levels of target genes through the activation of nuclear receptors. Retinoic acid receptor α (RAR α, retinoic acid receptor γ (RAR γ, and retinoid X receptor α (RXR α are expressed in the cornea and immune cells. This paper summarizes new findings regarding ATRA in immune and inflammatory diseases and analyzes the perspective application of ATRA in FK.

  17. Nuclear Receptor HNF4α Binding Sequences are Widespread in Alu Repeats

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    Bolotin Eugene

    2011-11-01

    Full Text Available Abstract Background Alu repeats, which account for ~10% of the human genome, were originally considered to be junk DNA. Recent studies, however, suggest that they may contain transcription factor binding sites and hence possibly play a role in regulating gene expression. Results Here, we show that binding sites for a highly conserved member of the nuclear receptor superfamily of ligand-dependent transcription factors, hepatocyte nuclear factor 4alpha (HNF4α, NR2A1, are highly prevalent in Alu repeats. We employ high throughput protein binding microarrays (PBMs to show that HNF4α binds > 66 unique sequences in Alu repeats that are present in ~1.2 million locations in the human genome. We use chromatin immunoprecipitation (ChIP to demonstrate that HNF4α binds Alu elements in the promoters of target genes (ABCC3, APOA4, APOM, ATPIF1, CANX, FEMT1A, GSTM4, IL32, IP6K2, PRLR, PRODH2, SOCS2, TTR and luciferase assays to show that at least some of those Alu elements can modulate HNF4α-mediated transactivation in vivo (APOM, PRODH2, TTR, APOA4. HNF4α-Alu elements are enriched in promoters of genes involved in RNA processing and a sizeable fraction are in regions of accessible chromatin. Comparative genomics analysis suggests that there may have been a gain in HNF4α binding sites in Alu elements during evolution and that non Alu repeats, such as Tiggers, also contain HNF4α sites. Conclusions Our findings suggest that HNF4α, in addition to regulating gene expression via high affinity binding sites, may also modulate transcription via low affinity sites in Alu repeats.

  18. Nuclear trafficking of secreted factors and cell-surface receptors: new pathways to regulate cell proliferation and differentiation, and involvement in cancers

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    Planque Nathalie

    2006-10-01

    Full Text Available Abstract Secreted factors and cell surface receptors can be internalized by endocytosis and translocated to the cytoplasm. Instead of being recycled or proteolysed, they sometimes translocate to the nucleus. Nuclear import generally involves a nuclear localization signal contained either in the secreted factor or its transmembrane receptor, that is recognized by the importins machinery. In the nucleus, these molecules regulate transcription of specific target genes by direct binding to transcription factors or general coregulators. In addition to the transcription regulation, nuclear secreted proteins and receptors seem to be involved in other important processes for cell life and cellular integrity such as DNA replication, DNA repair and RNA metabolism. Nuclear secreted proteins and transmembrane receptors now appear to induce new signaling pathways to regulate cell proliferation and differentiation. Their nuclear localization is often transient, appearing only during certain phases of the cell cycle. Nuclear secreted and transmembrane molecules regulate the proliferation and differentiation of a large panel of cell types during embryogenesis and adulthood and are also potentially involved in wound healing. Secreted factors such as CCN proteins, EGF, FGFs and their receptors are often detected in the nucleus of cancer cells. Nuclear localization of these molecules has been correlated with tumor progression and poor prognosis for patient survival. Nuclear growth factors and receptors may be responsible for resistance to radiotherapy.

  19. Expression Profiles of the Nuclear Receptors and Their Transcriptional Coregulators During Differentiation of Neural Stem Cells

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    Androutsellis-Theotokis, A.; Chrousos, G. P.; McKay, R. D.; DeCherney, A. H.; Kino, T.

    2013-01-01

    Neural stem cells (NSCs) are pluripotent precursors with the ability to proliferate and differentiate into 3 neural cell lineages, neurons, astrocytes and oligodendrocytes. Elucidation of the mechanisms underlying these biologic processes is essential for understanding both physiologic and pathologic neural development and regeneration after injury. Nuclear hormone receptors (NRs) and their transcriptional coregulators also play crucial roles in neural development, functions and fate. To identify key NRs and their transcriptional regulators in NSC differentiation, we examined mRNA expression of 49 NRs and many of their coregulators during differentiation (0–5 days) of mouse embryonic NSCs induced by withdrawal of fibroblast growth factor-2 (FGF2). 37 out of 49 NRs were expressed in NSCs before induction of differentiation, while receptors known to play major roles in neural development, such as THRα, RXRs, RORs, TRs, and COUPTFs, were highly expressed. CAR, which plays important roles in xenobiotic metabolism, was also highly expressed. FGF2 withdrawal induced mRNA expression of RORγ, RXRγ, and MR by over 20-fold. Most of the transcriptional coregulators examined were expressed basally and throughout differentiation without major changes, while FGF2 withdrawal strongly induced mRNA expression of several histone deacetylases (HDACs), including HDAC11. Dexamethasone and aldosterone, respectively a synthetic glucocorticoid and natural mineralocorticoid, increased NSC numbers and induced differentiation into neurons and astrocytes. These results indicate that the NRs and their coregulators are present and/or change their expression during NSC differentiation, suggesting that they may influence development of the central nervous system in the absence or presence of their ligands. PMID:22990992

  20. Cysteine (C-x-C receptor 4 undergoes transportin 1-dependent nuclear localization and remains functional at the nucleus of metastatic prostate cancer cells.

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    Ayesha S Don-Salu-Hewage

    Full Text Available The G-protein coupled receptor (GPCR, Cysteine (C-X-C Receptor 4 (CXCR4, plays an important role in prostate cancer metastasis. CXCR4 is generally regarded as a plasma membrane receptor where it transmits signals that support transformation, progression and eventual metastasis. Due to the central role of CXCR4 in tumorigenesis, therapeutics approaches such as antagonist and monoclonal antibodies have focused on receptors that exist on the plasma membrane. An emerging concept for G-protein coupled receptors is that they may localize to and associate with the nucleus where they retain function and mediate nuclear signaling. Herein, we demonstrate that CXCR4 associated with the nucleus of malignant prostate cancer tissues. Likewise, expression of CXCR4 was detected in nuclear fractions among several prostate cancer cell lines, compared to normal prostate epithelial cells. Our studies identified a nuclear pool of CXCR4 and we defined a nuclear transport pathway for CXCR4. We reveal a putative nuclear localization sequence (NLS, 'RPRK', within CXCR4 that contributed to nuclear localization. Additionally, nuclear CXCR4 interacted with Transportinβ1 and Transportinβ1-binding to CXCR4 promoted its nuclear translocation. Importantly, Gαi immunoprecipitation and calcium mobilization studies indicated that nuclear CXCR4 was functional and participated in G-protein signaling, revealing that the nuclear pool of CXCR4 retained function. Given the suggestion that functional, nuclear CXCR4 may be a mechanism underlying prostate cancer recurrence, increased metastatic ability and poorer prognosis after tumors have been treated with therapy that targets plasma membrane CXCR4, these studies addresses a novel mechanism of nuclear signaling for CXCR4, a novel mechanism of clinical targeting, and demonstrate an active nuclear pool that provides important new information to illuminate what has been primarily clinical reports of nuclear CXCR4.

  1. Transcription coactivators p300 and CBP are necessary for photoreceptor-specific chromatin organization and gene expression.

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    Anne K Hennig

    Full Text Available Rod and cone photoreceptor neurons in the mammalian retina possess specialized cellular architecture and functional features for converting light to a neuronal signal. Establishing and maintaining these characteristics requires appropriate expression of a specific set of genes, which is tightly regulated by a network of photoreceptor transcription factors centered on the cone-rod homeobox protein CRX. CRX recruits transcription coactivators p300 and CBP to acetylate promoter-bound histones and activate transcription of target genes. To further elucidate the role of these two coactivators, we conditionally knocked out Ep300 and/or CrebBP in differentiating rods or cones, using opsin-driven Cre recombinase. Knockout of either factor alone exerted minimal effects, but loss of both factors severely disrupted target cell morphology and function: the unique nuclear chromatin organization seen in mouse rods was reversed, accompanied by redistribution of nuclear territories associated with repressive and active histone marks. Transcription of many genes including CRX targets was severely impaired, correlating with reduced histone H3/H4 acetylation (the products of p300/CBP on target gene promoters. Interestingly, the presence of a single wild-type allele of either coactivator prevented many of these defects, with Ep300 more effective than Cbp. These results suggest that p300 and CBP play essential roles in maintaining photoreceptor-specific structure, function and gene expression.

  2. Role of nuclear receptor NR4A2 in gastrointestinal inflammation and cancers

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    Yi-Fang Han; Guang-Wen Cao

    2012-01-01

    NR4A2 is a transcription factor belonging to the steroid orphan nuclear receptor superfamily.It was originally considered to be essential in the generation and maintenance of dopaminergic neurons,and associated with neurological disorders such as Parkinson's disease.Recently,NR4A2 has been found to play a critical role in some inflammatory diseases and cancer.NR4A2 can be efficiently trans-activated by some proinflammatory cytokines,such as tumor necrosis factor-α,interleukin-1β,and vascular endothelial growth factor (VEGF).The nuclear factor-κB signaling pathway serves as a principal regulator of inducible NR4A expression in immune cells.NR4A2 can trans-activate Foxp3,a hallmark specifically expressed in regulatory T (Treg) cells,and plays a critical role in the differentiation,maintenance,and function of Treg cells.NR4A2 in T lymphocytes is pivotal for Treg cell induction and suppression of aberrant induction of Th1 under physiological and pathological conditions.High density of Foxp3+ Treg cells is significantly associated with gastrointestinal inflammation,tumor immune escape,and disease progression.NR4A2 is produced at high levels in CD133+ colorectal carcinoma (CRC) cells and significantly upregulated by cyclooxygenase-2-derived prostaglandin E2 in a cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)-dependent manner in CRC cells.The cAMP/PKA signaling pathway is the common pathway of NR4A2-related inflammation and cancer.NR4A2 trans-activates osteopontin,a direct target of the Wnt/β-catenin pathway associated with CRC invasion,metastasis,and poor prognosis.Knockdown of endogenous NR4A2 expression attenuates VEGF-induced endothelial cell proliferation,migration and in vivo angiogenesis.Taken together,NR4A2 emerges as an important nuclear factor linking gastrointestinal inflammation and cancer,especially CRC,and should serve as a candidate therapeutic target for inflammation-related gastrointestinal cancer.

  3. Multifunctional human transcriptional coactivator protein PC4 is a substrate of Aurora kinases and activates the Aurora enzymes.

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    Dhanasekaran, Karthigeyan; Kumari, Sujata; Boopathi, Ramachandran; Shima, Hiroki; Swaminathan, Amrutha; Bachu, Mahesh; Ranga, Udaykumar; Igarashi, Kazuhiko; Kundu, Tapas K

    2016-03-01

    Positive coactivator 4 (PC4), a human transcriptional coactivator, is involved in diverse processes like chromatin organization and transcription regulation. It is hyperphosphorylated during mitosis, with unknown significance. For the first time, we demonstrate the function of PC4 outside the nucleus upon nuclear envelope breakdown. A fraction of PC4 associates with Aurora A and Aurora B and undergoes phosphorylation, following which PC4 activates both Aurora A and B to sustain optimal kinase activity to maintain the phosphorylation gradient for the proper functioning of the mitotic machinery. This mitotic role is evident in PC4 knockdown cells where the defects are rescued only by the catalytically active Aurora kinases, but not the kinase-dead mutants. Similarly, the PC4 phosphodeficient mutant failed to rescue such defects. Hence, our observations establish a novel mitotic function of PC4 that might be dependent on Aurora kinase-mediated phosphorylation.

  4. p53 SUMOylation promotes its nuclear export by facilitating its release from the nuclear export receptor CRM1.

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    Santiago, Aleixo; Li, Dawei; Zhao, Lisa Y; Godsey, Adam; Liao, Daiqing

    2013-09-01

    Chromosomal region maintenance 1 (CRM1) mediates p53 nuclear export. Although p53 SUMOylation promotes its nuclear export, the underlying mechanism is unclear. Here we show that tethering of a small, ubiquitin-like modifier (SUMO) moiety to p53 markedly increases its cytoplasmic localization. SUMO attachment to p53 does not affect its oligomerization, suggesting that subunit dissociation required for exposing p53's nuclear export signal (NES) is unnecessary for p53 nuclear export. Surprisingly, SUMO-mediated p53 nuclear export depends on the SUMO-interacting motif (SIM)-binding pocket of SUMO-1. The CRM1 C-terminal domain lacking the NES-binding groove interacts with tetrameric p53, and the proper folding of the p53 core domain, rather than the presence of the N- or C-terminal tails, appears to be important for p53-CRM1 interaction. The CRM1 Huntington, EF3, a subunit of PP2A, and TOR1 9 (HEAT9) loop, which regulates GTP-binding nuclear protein Ran binding and cargo release, contains a prototypical SIM. Remarkably, disruption of this SIM in conjunction with a mutated SIM-binding groove of SUMO-1 markedly enhances the binding of CRM1 to p53-SUMO-1 and their accumulation in the nuclear pore complexes (NPCs), as well as their persistent association in the cytoplasm. We propose that SUMOylation of a CRM1 cargo such as p53 at the NPCs unlocks the HEAT9 loop of CRM1 to facilitate the disassembly of the transporting complex and cargo release to the cytoplasm.

  5. Indoxyl Sulfate Downregulates Mas Receptor via Aryl Hydrocarbon Receptor/Nuclear Factor-kappa B, and Induces Cell Proliferation and Tissue Factor Expression in Vascular Smooth Muscle Cells.

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    Ng, Hwee-Yeong; Bolati, Wulaer; Lee, Chien-Te; Chien, Yu-Shu; Yisireyili, Maimaiti; Saito, Shinichi; Pei, Sung-Nan; Nishijima, Fuyuhiko; Niwa, Toshimitsu

    2016-01-01

    Angiotensin converting enzyme-related carboxypeptidase 2/angiotensin (Ang)-(1-7)/Mas receptor axis is protective in the development of chronic kidney disease and cardiovascular disease. This study is aimed at investigating whether indoxyl sulfate (IS) affects Mas receptor expression, cell proliferation and tissue factor expression in vascular smooth muscle cells, and if Ang-(1-7), an activator of Mas receptor, counteracts the IS-induced effects. IS was administered to normotensive and hypertensive rats. Human aortic smooth muscle cells (HASMCs) were cultured with IS. IS reduced the expression of Mas receptor in the aorta of normotensive and hypertensive rats. IS downregulated the Mas receptor expression in a time- and dose-dependent manner in HASMCs. Knockdown of aryl hydrocarbon receptor (AhR) and nuclear factor-kappa B (NF-x03BA;B) inhibited IS-induced downregulation of Mas receptor. Further, IS stimulated cell proliferation and tissue factor expression in HASMCs. Ang-(1-7) attenuated IS-induced cell proliferation and tissue factor expression in HASMCs. Ang-(1-7) suppressed phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and NF-x03BA;B in HASMCs. IS downregulated the expression of Mas receptor via AhR/NF-x03BA;B, and induced cell proliferation and tissue factor expression in HASMCs. Ang-(1-7) inhibited IS-induced cell proliferation and tissue factor expression by suppressing the phosphorylation of ERK1/2 and NF-x03BA;B p65. © 2016 S. Karger AG, Basel.

  6. The Substitution Principle within the REACH Regulation: Nuclear Receptor-Bound Endocrine Disruptors

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    Stefano Lorenzetti

    2017-09-01

    Full Text Available Within the REACH Regulation (EC/1907/2006, the substitution principle for chemicals classified as Substances of Very High Concern (SVHC for either human health or environmental risks has been implemented in order to support their replacement by suitable alternatives. Considering the thousands of chemicals to be tested within the frame of REACH, animal testing by internationally-accepted guidelines sounds unreasonable in terms of the required time, costs as well ethical issues. Hence, REACH recommended also the use of alternative methods to animal experimentation although no validated in silico or in vitro tools were available when regulation entried into force. To search for suitable alternatives to SVHC having an Endocrine Disruptor (ED-like Mode-of-Action (MoA by means of an integrated, tiered in silico-in vitro approach, the EU-granted project LIFE-EDESIA (contract no. LIFE12 ENV/IT/000633 is combining computational-based tools and cell-based bioassays, in order to develop a no-animal testing procedure to screen for chemicals having less or no toxicity in terms of endocrine disruption-like activities. A general view of the no-animal testing approach implementing REACH and the substitution principle will be given, emphasising ligand-nuclear receptor (NR assessment by molecular docking (one of the LIFE-EDESIA in silico approaches and the use of clinical biomarkers in in vitro toxicology to detect ED-like adverse effects in cell-based bioassays.

  7. Nuclear receptors and epigenetic regulation: opportunities for nutritional targeting and disease prevention.

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    Romagnolo, Donato F; Zempleni, Janos; Selmin, Ornella I

    2014-07-01

    Posttranslational modifications of histones, alterations in the recruitment and functions of non-histone proteins, DNA methylation, and changes in expression of noncoding RNAs contribute to current models of epigenetic regulation. Nuclear receptors (NRs) are a group of transcription factors that, through ligand-binding, act as sensors to changes in nutritional, environmental, developmental, pathophysiologic, and endocrine conditions and drive adaptive responses via gene regulation. One mechanism through which NRs direct gene expression is the assembly of transcription complexes with cofactors and coregulators that possess chromatin-modifying properties. Chromatin modifications can be transient or become part of the cellular "memory" and contribute to genomic imprinting. Because many food components bind to NRs, they can ultimately influence transcription of genes associated with biologic processes, such as inflammation, proliferation, apoptosis, and hormonal response, and alter the susceptibility to chronic diseases (e.g., cancer, diabetes, obesity). The objective of this review is to highlight how NRs influence epigenetic regulation and the relevance of dietary compound-NR interactions in human nutrition and for disease prevention and treatment. Identifying gene targets of unliganded and bound NRs may assist in the development of epigenetic maps for food components and dietary patterns. Progress in these areas may lead to the formulation of disease-prevention models based on epigenetic control by individual or associations of food ligands of NRs.

  8. The Major Prognostic Features of Nuclear Receptor NR5A2 in Infiltrating Ductal Breast Carcinomas

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    Li-Yun Chang

    2015-01-01

    Full Text Available Background. Gene expression profiles of 181 breast cancer samples were analyzed to identify prognostic features of nuclear receptors NR5A1 and NR5A2 based upon their associated transcriptional networks. Methods. A supervised network analysis approach was used to build the NR5A-mediated transcriptional regulatory network. Other bioinformatic tools and statistical methods were utilized to confirm and extend results from the network analysis methodology. Results. NR5A2 expression is a negative factor in breast cancer prognosis in both ER(− and ER(−/ER(+ mixed cohorts. The clinical and cohort significance of NR5A2-mediated transcriptional activities indicates that it may have a significant role in attenuating grade development and cancer related signal transduction pathways. NR5A2 signature that conditions poor prognosis was identified based upon results from 15 distinct probes. Alternatively, the expression of NR5A1 predicts favorable prognosis when concurrent NR5A2 expression is low. A favorable signature of eight transcription factors mediated by NR5A1 was also identified. Conclusions. Correlation of poor prognosis and NR5A2 activity is identified by NR5A2-mediated 15-gene signature. NR5A2 may be a potential drug target for treating a subset of breast cancer tumors across breast cancer subtypes, especially ER(− breast tumors. The favorable prognostic feature of NR5A1 is predicted by NR5A1-mediated 8-gene signature.

  9. Mice lacking TR4 nuclear receptor develop mitochondrial myopathy with deficiency in complex I.

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    Liu, Su; Lee, Yi-Fen; Chou, Samuel; Uno, Hideo; Li, Gonghui; Brookes, Paul; Massett, Michael P; Wu, Qiao; Chen, Lu-Min; Chang, Chawnshang

    2011-08-01

    The estimated incidence of mitochondrial diseases in humans is approximately 1:5000 to 1:10,000, whereas the molecular mechanisms for more than 50% of human mitochondrial disease cases still remain unclear. Here we report that mice lacking testicular nuclear receptor 4 (TR4(-/-)) suffered mitochondrial myopathy, and histological examination of TR4(-/-) soleus muscle revealed abnormal mitochondrial accumulation. In addition, increased serum lactate levels, decreased mitochondrial ATP production, and decreased electron transport chain complex I activity were found in TR4(-/-) mice. Restoration of TR4 into TR4(-/-) myoblasts rescued mitochondrial ATP generation capacity and complex I activity. Further real-time PCR quantification and promoter studies found TR4 could modulate complex I activity via transcriptionally regulating the complex I assembly factor NDUFAF1, and restoration of NDUFAF1 level in TR4(-/-) myoblasts increased mitochondrial ATP generation capacity and complex I activity. Together, these results suggest that TR4 plays vital roles in mitochondrial function, which may help us to better understand the pathogenesis of mitochondrial myopathy, and targeting TR4 via its ligands/activators may allow us to develop better therapeutic approaches.

  10. The nuclear orphan receptor COUP-TFII is required for limb and skeletal muscle development.

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    Lee, Christopher T; Li, Luoping; Takamoto, Norio; Martin, James F; Demayo, Francesco J; Tsai, Ming-Jer; Tsai, Sophia Y

    2004-12-01

    The nuclear orphan receptor COUP-TFII is widely expressed in multiple tissues and organs throughout embryonic development, suggesting that COUP-TFII is involved in multiple aspects of embryogenesis. Because of the early embryonic lethality of COUP-TFII knockout mice, the role of COUP-TFII during limb development has not been determined. COUP-TFII is expressed in lateral plate mesoderm of the early embryo prior to limb bud formation. In addition, COUP-TFII is also expressed in the somites and skeletal muscle precursors of the limbs. Therefore, in order to study the potential role of COUP-TFII in limb and skeletal muscle development, we bypassed the early embryonic lethality of the COUP-TFII mutant by using two methods. First, embryonic chimera analysis has revealed an obligatory role for COUP-TFII in limb bud outgrowth since mutant cells are unable to contribute to the distally growing limb mesenchyme. Second, we used a conditional-knockout approach to ablate COUP-TFII specifically in the limbs. Loss of COUP-TFII in the limbs leads to hypoplastic skeletal muscle development, as well as shorter limbs. Taken together, our results demonstrate that COUP-TFII plays an early role in limb bud outgrowth but not limb bud initiation. Also, COUP-TFII is required for appropriate development of the skeletal musculature of developing limbs.

  11. Hepatic circadian clock oscillators and nuclear receptors integrate microbiome-derived signals

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    Montagner, Alexandra; Korecka, Agata; Polizzi, Arnaud; Lippi, Yannick; Blum, Yuna; Canlet, Cécile; Tremblay-Franco, Marie; Gautier-Stein, Amandine; Burcelin, Rémy; Yen, Yi-Chun; Je, Hyunsoo Shawn; Maha, Al-Asmakh; Mithieux, Gilles; Arulampalam, Velmurugesan; Lagarrigue, Sandrine; Guillou, Hervé; Pettersson, Sven; Wahli, Walter

    2016-01-01

    The liver is a key organ of metabolic homeostasis with functions that oscillate in response to food intake. Although liver and gut microbiome crosstalk has been reported, microbiome-mediated effects on peripheral circadian clocks and their output genes are less well known. Here, we report that germ-free (GF) mice display altered daily oscillation of clock gene expression with a concomitant change in the expression of clock output regulators. Mice exposed to microbes typically exhibit characterized activities of nuclear receptors, some of which (PPARα, LXRβ) regulate specific liver gene expression networks, but these activities are profoundly changed in GF mice. These alterations in microbiome-sensitive gene expression patterns are associated with daily alterations in lipid, glucose, and xenobiotic metabolism, protein turnover, and redox balance, as revealed by hepatic metabolome analyses. Moreover, at the systemic level, daily changes in the abundance of biomarkers such as HDL cholesterol, free fatty acids, FGF21, bilirubin, and lactate depend on the microbiome. Altogether, our results indicate that the microbiome is required for integration of liver clock oscillations that tune output activators and their effectors, thereby regulating metabolic gene expression for optimal liver function. PMID:26879573

  12. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells

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    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng, E-mail: oxyccc@163.com

    2015-12-04

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. - Highlights: • TLX overexpression in MIN6 cell causes significant expression changes of 225 genes. • TLX overexpression promotes MIN6 cell proliferation and decreases cell apoptosis. • TLX overexpression does not cause impairment of insulin secretion.

  13. The orphan nuclear receptor SHP is a positive regulator of osteoblastic bone formation.

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    Jeong, Byung-Chul; Lee, Yong-Soo; Bae, In-Ho; Lee, Chul-Ho; Shin, Hong-In; Ha, Hyun Jung; Franceschi, Renny T; Choi, Hueng-Sik; Koh, Jeong-Tae

    2010-02-01

    The orphan nuclear receptor small heterodimer partner (SHP; NR0B2) interacts with a diverse array of transcription factors and regulates a variety of cellular events such as cell proliferation, differentiation, and metabolism. However, the role of SHP in bone formation has not yet been elucidated. SHP expression is significantly increased during osteoblast differentiation, and its expression is partially regulated by bone morphogenetic protein 2 (BMP-2), which plays an important role in bone formation. In our study, inhibition of SHP expression significantly repressed BMP-2-induced osteoblast differentiation and ectopic bone formation. In accordance with these in vitro and in vivo results, osteoblast differentiation in SHP(-/-) mice primary osteoblasts was significantly repressed, and the mice showed decreased bone mass resulting from decreased numbers of osteoblasts. Finally, SHP physically interacts and forms a complex with runt-related transcription factor 2 (Runx2) on the osteocalcin gene promoter, and overexpression of SHP increased Runx2 transactivity via competition with histone deacetylase 4 (HDAC4), an enzyme that inhibits DNA binding of Runx2 to its target genes. Taken together, these results indicate that SHP acts as a novel positive regulator of bone formation by augmenting osteoblast differentiation through regulation of the transcriptional activity of Runx2.

  14. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells.

    Science.gov (United States)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is