Corepressive function of nuclear receptor coactivator 2 in androgen receptor of prostate cancer cells treated with antiandrogen

International Nuclear Information System (INIS)

Takeda, Keisuke; Hara, Noboru; Nishiyama, Tsutomu; Tasaki, Masayuki; Ishizaki, Fumio; Tomita, Yoshihiko

2016-01-01

Recruitment of cofactors in the interaction of the androgen receptor (AR) and AR ligands plays a critical role in determining androgenic/antiandrogenic effects of the AR ligand on signaling, but the functions of key cofactors, including nuclear receptor coactivator (NCOA), remain poorly understood in prostate cancer cells treated with AR ligands. We examined prostate cancer cell lines LNCaP and VCaP expressing mutated and wild-type ARs, respectively, to clarify the significance of NCOAs in the effect of antiandrogens. Hydroxyflutamide showed antagonistic activity against VCaP and an agonistic effect on LNCaP. Bicalutamide served as an antagonist for both. We analyzed mRNA transcription and protein expression of NCOAs in these cells pretreated with dihydrotestosterone and thereafter treated with the mentioned antiandrogens. Transcriptional silencing of candidate NCOAs and AR was performed using small interfering RNA (siRNA). Cell proliferation was evaluated with MTT assay. LNCaP treated with bicalutamide showed an about four-fold increase in the expression of NCOA2 mRNA compared to those pretreated with dihydrotestosterone alone (P <0.01). In VCaP pretreated with dihydrotestosterone, transcriptions of NCOA2 and NCOA7 were slightly increased with bicalutamide (1.96- and 2.42-fold, respectively) and hydroxyflutamide (1.33-fold in both). With Western blotting, the expression of NCOA2 protein also increased in LNCaP cells treated with bicalutamide compared with that in control cells pretreated with dihydrotestosterone alone. Following silencing with siRNA for NCOA2, PSA levels in media with LNCaP receiving bicalutamide were elevated compared with those in non-silencing controls (101.6 ± 4.2 vs. 87.8 ± 1.4 ng/mL, respectively, P =0.0495). In LNCaP cells treated with dihydrotestosterone and bicalutamide, NCOA2-silencing was associated with a higher proliferation activity compared with non-silencing control and AR-silencing. NCOA2, which has been thought to be recruited

Reverting doxorubicin resistance in colon cancer by targeting a key signaling protein, steroid receptor coactivator.

Science.gov (United States)

Xiong, Sang; Xiao, Gong-Wei

2018-04-01

Although there have been notable improvements in treatments against cancer, further research is required. In colon cancer, nearly all patients eventually experience drug resistance and stop responding to the approved drugs, making treatment difficult. Steroid receptor coactivator (SRC) is an oncogenic nuclear receptor coactivator that serves an important role in drug resistance. The present study generated a doxorubicin-resistant colon cancer cell line, in which the upregulation/activation of SRC was responsible for drug resistance, which in turn activated AKT. Overexpression of receptor tyrosine kinase-like epidermal growth factor receptor and insulin-like growth factor 1 receptor also induced SRC expression. It was observed that doxorubicin resistance in colon cancer also induced epithelial to mesenchymal transition, a decrease in expression of epithelial marker E-cadherin and an increase in the expression of mesenchymal markers, including N-cadherin and vimentin. Additionally, the present study indicated that SRC acts as a common signaling node, and inhibiting SRC in combination with doxorubicin treatment in doxorubicin-resistant cells aids in reversing the resistance. Thus, the present study suggests that activation of SRC is responsible for doxorubicin resistance in colon cancer. However, further research is required to understand the complete mechanism of how drug resistance occurs and how it may be tackled to treat patients.

Ligand-independent recruitment of steroid receptor coactivators to estrogen receptor by cyclin D1

NARCIS (Netherlands)

Zwijsen, R.M.L.; Buckle, R.S.; Hijmans, E.M.; Loomans, C.J.M.; Bernards, R.A.

1998-01-01

The estrogen receptor (ER) is an important regulator of growth and differentiation of breast epithelium. Transactivation by ER depends on a leucine-rich motif, which constitutes a ligand-regulated binding site for steroid receptor coactivators (SRCs). Cyclin D1 is frequently amplified in breast

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...

MTA family of coregulators in nuclear receptor biology and pathology

Science.gov (United States)

Manavathi, Bramanandam; Singh, Kamini; Kumar, Rakesh

2007-01-01

Nuclear receptors (NRs) rely on coregulators (coactivators and corepressors) to modulate the transcription of target genes. By interacting with nucleosome remodeling complexes, NR coactivators potentiate transcription, whereas corepressors inhibit transcription of the target genes. Metastasis-associated proteins (MTA) represent an emerging family of novel NR coregulators. In general, MTA family members form independent nucleosome remodeling and deacetylation (NuRD) complexes and repress the transcription of different genes by recruiting histone deacetylases onto their target genes. However, MTA1 also acts as a coactivator in a promoter-context dependent manner. Recent findings that repression of estrogen receptor transactivation functions by MTA1, MTA1s, and MTA2 and regulation of MTA3 by estrogen signaling have indicated the significance of these proteins in NR signaling. Here, we highlight the action of MTA proteins on NR signaling and their roles in pathophysiological conditions. PMID:18174918

Dual roles for coactivator activator and its counterbalancing isoform coactivator modulator in human kidney cell tumorigenesis.

Science.gov (United States)

Kang, Yun Kyoung; Schiff, Rachel; Ko, Lan; Wang, Tao; Tsai, Sophia Y; Tsai, Ming-Jer; O'Malley, Bert W

2008-10-01

Coactivator activator (CoAA) has been reported to be a coactivator that regulates steroid receptor-mediated transcription and alternative RNA splicing. Herein, we show that CoAA is a dual-function coregulator that inhibits G(1)-S transition in human kidney cells and suppresses anchorage-independent growth and xenograft tumor formation. Suppression occurs in part by down-regulating c-myc and its downstream effectors ccnd1 and skp2 and causing accumulation of p27/Kip1 protein. In this cellular setting, CoAA directly represses the proto-oncogene c-myc by recruiting HDAC3 protein and decreasing both the acetylation of histone H3 and the presence of RNA polymerase II on the c-myc promoter. Interestingly, a splicing isoform of CoAA, coactivator modulator (CoAM), antagonizes CoAA-induced G(1)-S transition and growth inhibition by negatively regulating the mRNA levels of the endogenous CoAA isoform. In addition, we found that expression of CoAA protein is significantly decreased in human renal cell carcinoma compared with normal kidney. Our study presents evidence that CoAA is a potential tumor suppressor in renal carcinoma and that CoAM is a counterbalancing splice isoform. This is, thus far, the only example of a nuclear receptor coregulator involved in suppression of kidney cancer and suggests potentially significant new roles for coregulators in renal cancer biology.

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.

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

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Marc Liesa

Full Text Available 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.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.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.

A liver X receptor (LXR)-β alternative splicing variant (LXRBSV) acts as an RNA co-activator of LXR-β

International Nuclear Information System (INIS)

Hashimoto, Koshi; Ishida, Emi; Matsumoto, Shunichi; Shibusawa, Nobuyuki; Okada, Shuichi; Monden, Tsuyoshi; Satoh, Tetsurou; Yamada, Masanobu; Mori, Masatomo

2009-01-01

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)-β LXRBSV has an intronic sequence between exons 2 and 3 in the mouse LXR-β 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-β. 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.

Cell cycle-dependent expression of Dub3, Nanog and the p160 family of nuclear receptor coactivators (NCoAs in mouse embryonic stem cells.

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Siem van der Laan

Full Text Available Pluripotency of embryonic stem cells (ESC is tightly regulated by a network of transcription factors among which the estrogen-related receptor β (Esrrb. Esrrb contributes to the relaxation of the G1 to S-phase (G1/S checkpoint in mouse ESCs by transcriptional control of the deubiquitylase Dub3 gene, contributing to Cdc25A persistence after DNA damage. We show that in mESCs, Dub3 gene expression is cell cycle regulated and is maximal prior G1/S transition. In addition, following UV-induced DNA damage in G1, Dub3 expression markedly increases in S-phase also suggesting a role in checkpoint recovery. Unexpectedly, we also observed cell cycle-regulation of Nanog expression, and not Oct4, reaching high levels prior to G1/S transition, finely mirroring Cyclin E1 fluctuations. Curiously, while Esrrb showed only limited cell-cycle oscillations, transcript levels of the p160 family of nuclear receptor coactivators (NCoAs displayed strong cell cycle-dependent fluctuations. Since NCoAs function in concert with Esrrb in transcriptional activation, we focussed on NCoA1 whose levels specifically increase prior onset of Dub3 transcription. Using a reporter assay, we show that NCoA1 potentiates Esrrb-mediated transcription of Dub3 and we present evidence of protein interaction between the SRC1 splice variant NCoA1 and Esrrb. Finally, we show a differential developmental regulation of all members of the p160 family during neural conversion of mESCs. These findings suggest that in mouse ESCs, changes in the relative concentration of a coactivator at a given cell cycle phase, may contribute to modulation of the transcriptional activity of the core transcription factors of the pluripotent network and be implicated in cell fate decisions upon onset of differentiation.

Cell cycle-dependent expression of Dub3, Nanog and the p160 family of nuclear receptor coactivators (NCoAs) in mouse embryonic stem cells.

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van der Laan, Siem; Golfetto, Eleonora; Vanacker, Jean-Marc; Maiorano, Domenico

2014-01-01

Pluripotency of embryonic stem cells (ESC) is tightly regulated by a network of transcription factors among which the estrogen-related receptor β (Esrrb). Esrrb contributes to the relaxation of the G1 to S-phase (G1/S) checkpoint in mouse ESCs by transcriptional control of the deubiquitylase Dub3 gene, contributing to Cdc25A persistence after DNA damage. We show that in mESCs, Dub3 gene expression is cell cycle regulated and is maximal prior G1/S transition. In addition, following UV-induced DNA damage in G1, Dub3 expression markedly increases in S-phase also suggesting a role in checkpoint recovery. Unexpectedly, we also observed cell cycle-regulation of Nanog expression, and not Oct4, reaching high levels prior to G1/S transition, finely mirroring Cyclin E1 fluctuations. Curiously, while Esrrb showed only limited cell-cycle oscillations, transcript levels of the p160 family of nuclear receptor coactivators (NCoAs) displayed strong cell cycle-dependent fluctuations. Since NCoAs function in concert with Esrrb in transcriptional activation, we focussed on NCoA1 whose levels specifically increase prior onset of Dub3 transcription. Using a reporter assay, we show that NCoA1 potentiates Esrrb-mediated transcription of Dub3 and we present evidence of protein interaction between the SRC1 splice variant NCoA1 and Esrrb. Finally, we show a differential developmental regulation of all members of the p160 family during neural conversion of mESCs. These findings suggest that in mouse ESCs, changes in the relative concentration of a coactivator at a given cell cycle phase, may contribute to modulation of the transcriptional activity of the core transcription factors of the pluripotent network and be implicated in cell fate decisions upon onset of differentiation.

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

Perturbation of estrogen receptor α localization with synthetic nona-arginine LXXLL-peptide coactivator binding inhibitors

NARCIS (Netherlands)

Carraz, M.; Zwart, W.; Phan, T.; Michalides, R.; Brunsveld, L.

2009-01-01

The interaction of estrogen receptor a (ERa) with the consensus LXXLL motifs of transcriptional coactivators provides an entry for functional ERa inhibition. Here, synthetic cell-permeable LXXLL peptide probes are brought forward that allow evaluation of the interaction of specific recognition

Epstein-Barr Virus Nuclear Antigen Leader Protein Coactivates EP300.

Science.gov (United States)

Wang, Chong; Zhou, Hufeng; Xue, Yong; Liang, Jun; Narita, Yohei; Gerdt, Catherine; Zheng, Amy Y; Jiang, Runsheng; Trudeau, Stephen; Peng, Chih-Wen; Gewurz, Benjamin E; Zhao, Bo

2018-05-01

Epstein-Barr virus nuclear antigen (EBNA) leader protein (EBNALP) is one of the first viral genes expressed upon B-cell infection. EBNALP is essential for EBV-mediated B-cell immortalization. EBNALP is thought to function primarily by coactivating EBNA2-mediated transcription. Chromatin immune precipitation followed by deep sequencing (ChIP-seq) studies highlight that EBNALP frequently cooccupies DNA sites with host cell transcription factors (TFs), in particular, EP300, implicating a broader role in transcription regulation. In this study, we investigated the mechanisms of EBNALP transcription coactivation through EP300. EBNALP greatly enhanced EP300 transcription activation when EP300 was tethered to a promoter. EBNALP coimmunoprecipitated endogenous EP300 from lymphoblastoid cell lines (LCLs). EBNALP W repeat serine residues 34, 36, and 63 were required for EP300 association and coactivation. Deletion of the EP300 histone acetyltransferase (HAT) domain greatly reduced EBNALP coactivation and abolished the EBNALP association. An EP300 bromodomain inhibitor also abolished EBNALP coactivation and blocked the EP300 association with EBNALP. EBNALP sites cooccupied by EP300 had significantly higher ChIP-seq signals for sequence-specific TFs, including SPI1, RelA, EBF1, IRF4, BATF, and PAX5. EBNALP- and EP300-cooccurring sites also had much higher H3K4me1 and H3K27ac signals, indicative of activated enhancers. EBNALP-only sites had much higher signals for DNA looping factors, including CTCF and RAD21. EBNALP coactivated reporters under the control of NF-κB or SPI1. EP300 inhibition abolished EBNALP coactivation of these reporters. Clustered regularly interspaced short palindromic repeat interference targeting of EBNALP enhancer sites significantly reduced target gene expression, including that of EP300 itself. These data suggest a previously unrecognized mechanism by which EBNALP coactivates transcription through subverting of EP300 and thus affects the expression of

Mutation analysis of peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) and relationships of identified amino acid polymorphisms to Type II diabetes mellitus

DEFF Research Database (Denmark)

Ek, J; Andersen, G; Urhammer, S A

2001-01-01

This study aimed to investigate if variability in the peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) gene is associated with Type II (non-insulin-dependent) diabetes mellitus.......This study aimed to investigate if variability in the peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) gene is associated with Type II (non-insulin-dependent) diabetes mellitus....

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 receptor-γ coactivator-1α, a coactivator of nuclear receptors, also strongly coactivated expression of NR5A-target genes. Reporter analysis revealed that peroxisome proliferator-activated receptor-γ coactivator-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.

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.

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.

Ablation of Steroid Receptor Coactivator-3 resembles the human CACT metabolic myopathy

OpenAIRE

York, Brian; Reineke, Erin L.; Sagen, Jørn V.; Nikolai, Bryan C.; Zhou, Suoling; Louet, Jean-Francois; Chopra, Atul R.; Chen, Xian; Reed, Graham; Noebels, Jeffrey; Adesina, Adekunle M.; Yu, Hui; Wong, Lee-Jun C.; Tsimelzon, Anna; Hilsenbeck, Susan

2012-01-01

Oxidation of lipid substrates is essential for survival in fasting and other catabolic conditions, sparing glucose for the brain and other glucose-dependent tissues. Here we show Steroid Receptor Coactivator-3 (SRC-3) plays a central role in long chain fatty acid metabolism by directly regulating carnitine/acyl-carnitine translocase (CACT) gene expression. Genetic deficiency of CACT in humans is accompanied by a constellation of metabolic and toxicity phenotypes including hypoketonemia, hypog...

Ablation of steroid receptor coactivator-3 resembles the human CACT metabolic myopathy.

Science.gov (United States)

York, Brian; Reineke, Erin L; Sagen, Jørn V; Nikolai, Bryan C; Zhou, Suoling; Louet, Jean-Francois; Chopra, Atul R; Chen, Xian; Reed, Graham; Noebels, Jeffrey; Adesina, Adekunle M; Yu, Hui; Wong, Lee-Jun C; Tsimelzon, Anna; Hilsenbeck, Susan; Stevens, Robert D; Wenner, Brett R; Ilkayeva, Olga; Xu, Jianming; Newgard, Christopher B; O'Malley, Bert W

2012-05-02

Oxidation of lipid substrates is essential for survival in fasting and other catabolic conditions, sparing glucose for the brain and other glucose-dependent tissues. Here we show Steroid Receptor Coactivator-3 (SRC-3) plays a central role in long chain fatty acid metabolism by directly regulating carnitine/acyl-carnitine translocase (CACT) gene expression. Genetic deficiency of CACT in humans is accompanied by a constellation of metabolic and toxicity phenotypes including hypoketonemia, hypoglycemia, hyperammonemia, and impaired neurologic, cardiac and skeletal muscle performance, each of which is apparent in mice lacking SRC-3 expression. Consistent with human cases of CACT deficiency, dietary rescue with short chain fatty acids drastically attenuates the clinical hallmarks of the disease in mice devoid of SRC-3. Collectively, our results position SRC-3 as a key regulator of β-oxidation. Moreover, these findings allow us to consider platform coactivators such as the SRCs as potential contributors to syndromes such as CACT deficiency, previously considered as monogenic. Copyright © 2012 Elsevier Inc. All rights reserved.

Cloning of a protein arginine methyltransferase PRMT1 homologue from Schistosoma mansoni: Evidence for roles in nuclear receptor signaling and RNA metabolism

International Nuclear Information System (INIS)

Mansure, Jose Joao; Furtado, Daniel Rodrigues; Bastos de Oliveira, Francisco Meirelles; Rumjanek, Franklin David; Franco, Gloria Regina; Fantappie, Marcelo Rosado

2005-01-01

The most studied arginine methyltransferase is the type I enzyme, which catalyzes the transfer of an S-adenosyl-L-methionine to a broad spectrum of substrates, including histones, RNA-transporting proteins, and nuclear hormone receptor coactivators. We cloned a cDNA encoding a protein arginine methyltransferase in Schistosoma mansoni (SmPRMT1). SmPRMT1 is highly homologous to the vertebrate PRMT1 enzyme. In vitro methylation assays showed that SmPRMT1 recombinant protein was able to specifically methylate histone H4. Two schistosome proteins likely to be involved in RNA metabolism, SMYB1 and SmSmD3, that display a number of RGG motifs, were strongly methylated by SmPRMT1. In vitro GST pull-down assays showed that SMYB1 and SmSmD3 physically interacted with SmPRMT1. Additional GST pull-down assay suggested the occurrence of a ternary complex including SmPRMT1, SmRXR1 nuclear receptor, and the p160 (SRC-1) nuclear receptor coactivator. Together, these data suggest a mechanism by which SmPRMT1 plays a role in nuclear receptor-mediated chromatin remodeling and RNA transactions

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......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....... Biophysical studies show that despite the molten globule nature of the domain, it contains a small cooperatively folded core. By NMR spectroscopy, we have demonstrated that the folded core of NCBD has a well ordered conformer with specific side chain packing. This conformer resembles the structure of the NCBD...

Targeting AR Variant-Coactivator Interactions to Exploit Prostate Cancer Vulnerabilities.

Science.gov (United States)

Magani, Fiorella; Peacock, Stephanie O; Rice, Meghan A; Martinez, Maria J; Greene, Ann M; Magani, Pablo S; Lyles, Rolando; Weitz, Jonathan R; Burnstein, Kerry L

2017-11-01

Castration-resistant prostate cancer (CRPC) progresses rapidly and is incurable. Constitutively active androgen receptor splice variants (AR-Vs) represent a well-established mechanism of therapeutic resistance and disease progression. These variants lack the AR ligand-binding domain and, as such, are not inhibited by androgen deprivation therapy (ADT), which is the standard systemic approach for advanced prostate cancer. Signaling by AR-Vs, including the clinically relevant AR-V7, is augmented by Vav3, an established AR coactivator in CRPC. Using mutational and biochemical studies, we demonstrated that the Vav3 Diffuse B-cell lymphoma homology (DH) domain interacted with the N-terminal region of AR-V7 (and full length AR). Expression of the Vav3 DH domain disrupted Vav3 interaction with and enhancement of AR-V7 activity. The Vav3 DH domain also disrupted AR-V7 interaction with other AR coactivators: Src1 and Vav2, which are overexpressed in PC. This Vav3 domain was used in proof-of-concept studies to evaluate the effects of disrupting the interaction between AR-V7 and its coactivators on CRPC cells. This disruption decreased CRPC cell proliferation and anchorage-independent growth, caused increased apoptosis, decreased migration, and resulted in the acquisition of morphological changes associated with a less aggressive phenotype. While disrupting the interaction between FL-AR and its coactivators decreased N-C terminal interaction, disrupting the interaction of AR-V7 with its coactivators decreased AR-V7 nuclear levels. Implications: This study demonstrates the potential therapeutic utility of inhibiting constitutively active AR-V signaling by disrupting coactivator binding. Such an approach is significant, as AR-Vs are emerging as important drivers of CRPC that are particularly recalcitrant to current therapies. Mol Cancer Res; 15(11); 1469-80. ©2017 AACR . ©2017 American Association for Cancer Research.

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

OpenAIRE

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...

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

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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.

Hormonal regulation of steroid receptor coactivator-1 mRNA in the male and female green anole brain.

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Kerver, H N; Wade, J

2015-03-01

Green anole lizards are seasonal breeders, with male sexual behaviour primarily regulated by an annual increase in testosterone. Morphological, biochemical and behavioural changes associated with reproduction are activated by testosterone, generally with a greater effect in the breeding season (BS) than in the nonbreeding season (NBS). The present study investigates the possibility that differences in a steroid receptor coactivator may regulate this seasonal difference in responsiveness to testosterone. In situ hybridisation was used to examine the expression of steroid receptor coactivator-1 (SRC-1) in the brains of gonadally intact male and female green anoles across breeding states. A second experiment examined gonadectomised animals with and without testosterone treatment. Gonadally intact males had more SRC-1 expressing cells in the preoptic area and larger volumes of this region as defined by these cells than females. Main effects of both sex and season (males > females and BS > NBS) were present in cell number and volume of the ventromedial hypothalamus. An interaction between sex and season suggested that high expression in BS males was driving these effects. In hormone-manipulated animals, testosterone treatment increased both the number of SRC-1 expressing cells in and volumes of the preoptic area and amygdala. These results suggest that testosterone selectively regulates SRC-1, and that this coactivator may play a role in facilitating reproductive behaviours across both sexes. However, changes in SRC-1 expression are not likely responsible for the seasonal change in responsiveness to testosterone. © 2014 British Society for Neuroendocrinology.

CCAAT/Enhancer Binding Protein-β Is a Transcriptional Regulator of Peroxisome-Proliferator-Activated Receptor-γ Coactivator-1α in the Regenerating Liver

OpenAIRE

Wang, Haitao; Peiris, T. Harshani; Mowery, A.; Le Lay, John; Gao, Yan; Greenbaum, Linda E.

2008-01-01

The transcriptional coactivator peroxisome-proliferator-activated receptor-γ coactivator-1α (PGC-1α) is induced in the liver in response to fasting and coordinates the activation of targets necessary for increasing energy production for gluconeogenesis and ketogenesis. After partial hepatectomy, the liver must restore its mass while maintaining metabolic homeostasis to ensure survival. Here we report that PGC-1α is rapidly and dramatically induced after hepatectomy, with an amplitude of induc...

Selective ligand activity at Nur/retinoid X receptor complexes revealed by dimer-specific bioluminescence resonance energy transfer-based sensors

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Giner, Xavier C; Cotnoir-White, David; Mader, Sylvie; Lévesque, Daniel

2017-01-01

Retinoid X receptors (RXR) play a role as master regulators due to their capacity to form heterodimers with other nuclear receptors. Accordingly, retinoid signaling is involved in multiple biological processes, including development, cell differentiation, metabolism and cell death. However, the role and functions of RXR in different heterodimer complexes remain unsolved, mainly because most RXR drugs (called rexinoids) are not selective to specific heterodimer complexes. This also strongly limits the use of rexinoids for specific therapeutic approaches. In order to better characterize rexinoids at specific nuclear receptor complexes, we have developed and optimized luciferase protein complementation-based Bioluminescence Resonance Energy Transfer (BRET) assays, which can directly measure recruitment of a co-activator motif fused to yellow fluorescent protein (YFP) by specific nuclear receptor dimers. To validate the assays, we compared rexinoid modulation of co-activator recruitment by RXR homodimer, and heterodimers Nur77/RXR and Nurr1/RXR. Results reveal that some rexinoids display selective co-activator recruitment activities with homo- or hetero-dimer complexes. In particular, SR11237 (BMS649) has increased potency for recruitment of co-activator motif and transcriptional activity with the Nur77/RXR heterodimer compared to other complexes. This technology should prove useful to identify new compounds with specificity for individual dimeric species formed by nuclear receptors. PMID:26148973

Peroxisome proliferator-activated receptor (PPAR)-binding protein (PBP) but not PPAR-interacting protein (PRIP) is required for nuclear translocation of constitutive androstane receptor in mouse liver

International Nuclear Information System (INIS)

Guo Dongsheng; Sarkar, Joy; Ahmed, Mohamed R.; Viswakarma, Navin; Jia Yuzhi; Yu Songtao; Sambasiva Rao, M.; Reddy, Janardan K.

2006-01-01

The constitutive androstane receptor (CAR) regulates transcription of phenobarbital-inducible genes that encode xenobiotic-metabolizing enzymes in liver. CAR is localized to the hepatocyte cytoplasm but to be functional, it translocates into the nucleus in the presence of phenobarbital-like CAR ligands. We now demonstrate that adenovirally driven EGFP-CAR, as expected, translocates into the nucleus of normal wild-type hepatocytes following phenobarbital treatment under both in vivo and in vitro conditions. Using this approach we investigated the role of transcription coactivators PBP and PRIP in the translocation of EGFP-CAR into the nucleus of PBP and PRIP liver conditional null mouse hepatocytes. We show that coactivator PBP is essential for nuclear translocation of CAR but not PRIP. Adenoviral expression of both PBP and EGFP-CAR restored phenobarbital-mediated nuclear translocation of exogenously expressed CAR in PBP null livers in vivo and in PBP null primary hepatocytes in vitro. CAR translocation into the nucleus of PRIP null livers resulted in the induction of CAR target genes such as CYP2B10, necessary for the conversion of acetaminophen to its hepatotoxic intermediate metabolite, N-acetyl-p-benzoquinone imine. As a consequence, PRIP-deficiency in liver did not protect from acetaminophen-induced hepatic necrosis, unlike that exerted by PBP deficiency. These results establish that transcription coactivator PBP plays a pivotal role in nuclear localization of CAR, that it is likely that PBP either enhances nuclear import or nuclear retention of CAR in hepatocytes, and that PRIP is redundant for CAR function

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.

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

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Maria Takacs

Full Text Available 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.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.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.

Antisense-mediated isoform switching of steroid receptor coactivator-1 in the central nucleus of the amygdala of the mouse brain

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Zalachoras Ioannis

2013-01-01

Full Text Available Abstract Background Antisense oligonucleotide (AON-mediated exon skipping is a powerful tool to manipulate gene expression. In the present study we investigated the potential of exon skipping by local injection in the central nucleus of the amygdala (CeA of the mouse brain. As proof of principle we targeted the splicing of steroid receptor coactivator-1 (SRC-1, a protein involved in nuclear receptor function. This nuclear receptor coregulator exists in two splice variants (SRC-1a and SRC-1e which display differential distribution and opposing activities in the brain, and whose mRNAs differ in a single SRC-1e specific exon. Methods For proof of principle of feasibility, we used immunofluorescent stainings to study uptake by different cell types, translocation to the nucleus and potential immunostimulatory effects at different time points after a local injection in the CeA of the mouse brain of a control AON targeting human dystrophin with no targets in the murine brain. To evaluate efficacy we designed an AON targeting the SRC-1e-specific exon and with qPCR analysis we measured the expression ratio of the two splice variants. Results We found that AONs were taken up by corticotropin releasing hormone expressing neurons and other cells in the CeA, and translocated into the cell nucleus. Immune responses after AON injection were comparable to those after sterile saline injection. A successful shift of the naturally occurring SRC-1a:SRC-1e expression ratio in favor of SRC-1a was observed, without changes in total SRC-1 expression. Conclusions We provide a proof of concept for local neuropharmacological use of exon skipping by manipulating the expression ratio of the two splice variants of SRC-1, which may be used to study nuclear receptor function in specific brain circuits. We established that exon skipping after local injection in the brain is a versatile and useful tool for the manipulation of splice variants for numerous genes that are relevant

Structural basis for corepressor assembly by the orphan nuclear receptor TLX.

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Zhi, Xiaoyong; Zhou, X Edward; He, Yuanzheng; Searose-Xu, Kelvin; Zhang, Chun-Li; Tsai, Chih-Cheng; Melcher, Karsten; Xu, H Eric

2015-02-15

The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Here we report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. In these structures, TLX adopts an autorepressed conformation in which its helix H12 occupies the coactivator-binding groove. Unexpectedly, H12 in this autorepressed conformation forms a novel binding pocket with residues from helix H3 that accommodates a short helix formed by the conserved ALXXLXXY motif of the Atro box. Mutations that weaken the TLX-Atrophin interaction compromise the repressive activity of TLX, demonstrating that this interaction is required for Atrophin to confer repressor activity to TLX. Moreover, the autorepressed conformation is conserved in the repressor class of orphan nuclear receptors, and mutations of corresponding residues in other members of this class of receptors diminish their repressor activities. Together, our results establish the functional conservation of the autorepressed conformation and define a key sequence motif in the Atro box that is essential for TLX-mediated repression. © 2015 Zhi et al.; Published by Cold Spring Harbor Laboratory Press.

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

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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

Recent progress in the development of protein-protein interaction inhibitors targeting androgen receptor-coactivator binding in prostate cancer.

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Biron, Eric; Bédard, François

2016-07-01

The androgen receptor (AR) is a key regulator for the growth, differentiation and survival of prostate cancer cells. Identified as a primary target for the treatment of prostate cancer, many therapeutic strategies have been developed to attenuate AR signaling in prostate cancer cells. While frontline androgen-deprivation therapies targeting either the production or action of androgens usually yield favorable responses in prostate cancer patients, a significant number acquire treatment resistance. Known as the castration-resistant prostate cancer (CRPC), the treatment options are limited for this advanced stage. It has been shown that AR signaling is restored in CRPC due to many aberrant mechanisms such as AR mutations, amplification or expression of constitutively active splice-variants. Coregulator recruitment is a crucial regulatory step in AR signaling and the direct blockade of coactivator binding to AR offers the opportunity to develop therapeutic agents that would remain effective in prostate cancer cells resistant to conventional endocrine therapies. Structural analyses of the AR have identified key surfaces involved in protein-protein interaction with coregulators that have been recently used to design and develop promising AR-coactivator binding inhibitors. In this review we will discuss the design and development of small-molecule inhibitors targeting the AR-coactivator interactions for the treatment of prostate cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis and biological evaluation of guanylhydrazone coactivator binding inhibitors for the estrogen receptor.

Science.gov (United States)

LaFrate, Andrew L; Gunther, Jillian R; Carlson, Kathryn E; Katzenellenbogen, John A

2008-12-01

Most patients with hormone-responsive breast cancer eventually develop resistance to traditional antiestrogens such as tamoxifen, and this has become a major obstacle in their treatment. We prepared and characterized the activity of a series of 16 guanylhydrazone small molecules that are designed to block estrogen receptor (ER) activity through a non-traditional mechanism, by directly interfering with coactivator binding to agonist-liganded ER. The inhibitory activity of these compounds was determined in cell-based transcription assays using ER-responsive reporter gene and mammalian two-hybrid assays. Several of the compounds gave IC(50) values in the low micromolar range. Two secondary assays were used to confirm that these compounds were acting through the proposed non-traditional mode of estrogen inhibitory action and not as conventional antagonists at the ligand binding site.

Expression, purification, crystallization and preliminary crystallographic study of isolated modules of the mouse coactivator-associated arginine methyltransferase 1

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Troffer-Charlier, Nathalie; Cura, Vincent; Hassenboehler, Pierre; Moras, Dino; Cavarelli, Jean, E-mail: cava@igbmc.u-strasbg.fr [IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Département de Biologie et Génomique Structurales, 1 Rue Laurent Fries, Illkirch, F-67404 (France); INSERM, U596, Illkirch, F-67400 (France); CNRS, UMR7104, Illkirch, F-67400 (France); Université Louis Pasteur, Faculté des Sciences de la Vie, Strasbourg, F-67000 (France)

2007-04-01

Isolated modules of mouse coactivator-associated arginine methyltransferase 1 encompassing the protein arginine N-methyltransferase catalytic domain have been overexpressed, purified and crystallized. X-ray diffraction data have been collected and have enabled determination of the structures by multiple isomorphous replacement using anomalous scattering. Coactivator-associated arginine methyltransferase 1 (CARM1) plays a crucial role in gene expression as a coactivator of several nuclear hormone receptors and also of non-nuclear receptor systems. Its recruitment by the transcriptional machinery induces protein methylation, leading to chromatin remodelling and gene activation. CARM1{sub 28–507} and two structural states of CARM1{sub 140–480} were expressed, purified and crystallized. Crystals of CARM1{sub 28–507} belong to space group P6{sub 2}22, with unit-cell parameters a = b = 136.0, c = 125.3 Å; they diffract to beyond 2.5 Å resolution using synchrotron radiation and contain one monomer in the asymmetric unit. The structure of CARM1{sub 28–507} was solved by multiple isomorphous replacement and anomalous scattering methods. Crystals of apo CARM1{sub 140–480} belong to space group I222, with unit-cell parameters a = 74.6, b = 99.0, c = 207.4 Å; they diffract to beyond 2.7 Å resolution and contain two monomers in the asymmetric unit. Crystals of CARM1{sub 140–480} in complex with S-adenosyl-l-homocysteine belong to space P2{sub 1}2{sub 1}2, with unit-cell parameters a = 74.6, b = 98.65, c = 206.08 Å; they diffract to beyond 2.6 Å resolution and contain four monomers in the asymmetric unit. The structures of apo and holo CARM1{sub 140–480} were solved by molecular-replacement techniques from the structure of CARM1{sub 28–507}.

An energetic orphan in an endocrine tissue: a revised perspective of the function of estrogen receptor-related receptor alpha in bone and cartilage.

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Bonnelye, Edith; Aubin, Jane E

2013-02-01

Estrogen receptor-related receptor alpha (ERRα) is an orphan nuclear receptor with sequence homology to the estrogen receptors, ERα/β, but it does not bind estrogen. ERRα not only plays a functional role in osteoblasts but also in osteoclasts and chondrocytes. In addition, the ERRs, including ERRα, can be activated by coactivators such as peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC1α and β) and are implicated in adipogenesis, fatty acid oxidation, and oxidative stress defense, suggesting that ERRα-through its activity in bone resorption and adipogenesis--may regulate the insulin and leptin pathways and contribute to aging-related changes in bone and cartilage. In this review, we discuss data on ERRα and its cellular and molecular modes of action, which have broad implications for considering the potential role of this orphan receptor in cartilage and bone endocrine function, on whole-organism physiology, and in the bone aging process. Copyright © 2013 American Society for Bone and Mineral Research.

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

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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.

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

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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.

Identification of VDR Antagonists among Nuclear Receptor Ligands Using Virtual Screening

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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.

Action mechanisms of Liver X Receptors

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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.

Action mechanisms of Liver X Receptors

International Nuclear Information System (INIS)

Gabbi, Chiara; Warner, Margaret; Gustafsson, Jan-Åke

2014-01-01

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

Isoflavones enhance interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

International Nuclear Information System (INIS)

Kojima, Hiroyuki; Takeda, Yukimasa; Muromoto, Ryuta; Takahashi, Miki; Hirao, Toru; Takeuchi, Shinji; Jetten, Anton M.; Matsuda, Tadashi

2015-01-01

Highlights: • Nuclear receptors, RORα and RORγ, are key regulators of Th17 cell differentiation. • Isoflavones have RORα/γ agonistic activities. • Isoflavones enhance the interaction of RORα/γ with co-activator. • These compounds enhance the expression of Il17a mRNA in mouse EL4 cells. • Dietary isoflavones can act as modulators of Il17a expression via RORα/γ. - Abstract: The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. In this study, we investigated the effects of isoflavones on RORα/γ activity and the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In doxycycline-inducible CHO stable cell lines, we found that four isoflavones, biochanin A (BA), genistein, formononetin, and daidzein, enhanced RORα- or RORγ-mediated transcriptional activity in a dose-dependent manner. In an activation assay of the Il17a promoter using Jurkat cells, these compounds enhanced the RORα- or RORγ-mediated activation of the Il17a promoter at concentrations of 1 × 10 −6 M to 1 × 10 −5 M. In mammalian two-hybrid assays, the four isoflavones enhanced the interaction between the RORα- or RORγ-ligand binding domain and the co-activator LXXLL peptide in a dose-dependent manner. In addition, these isoflavones potently enhanced Il17a mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin, but showed slight enhancement of Il17a gene expression in RORα/γ-knockdown EL4 cells. Immunoprecipitation and immunoblotting assays also revealed that BA enhanced the interaction between RORγt and SRC-1, which is a co-activator for nuclear receptors. Taken together, these results suggest that the isoflavones have the ability to enhance IL-17 gene expression by stabilizing the interactions between RORα/γ and co-activators. This also

Nuclear receptor ligand-binding domains: reduction of helix H12 dynamics to favour crystallization

Energy Technology Data Exchange (ETDEWEB)

Nahoum, Virginie; Lipski, Alexandra; Quillard, Fabien; Guichou, Jean-François [INSERM, U554, 34090 Montpellier (France); Université de Montpellier, CNRS, UMR5048, Centre de Biochimie Structurale (CBS), 34090 Montpellier (France); Boublik, Yvan [CNRS, UMR5237, Centre de Recherche de Biochimie Macromoléculaire (CRBM), 34293 Montpellier (France); Pérez, Efrèn [Universidade de Vigo, Departamento de Quimica Organica, Facultad de Química, 36310 Vigo (Spain); Germain, Pierre [Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), BP 10142, 67404 Illkirch CEDEX (France); Lera, Angel R. de [Universidade de Vigo, Departamento de Quimica Organica, Facultad de Química, 36310 Vigo (Spain); Bourguet, William, E-mail: bourguet@cbs.cnrs.fr [INSERM, U554, 34090 Montpellier (France); Université de Montpellier, CNRS, UMR5048, Centre de Biochimie Structurale (CBS), 34090 Montpellier (France)

2008-07-01

Attempts have been made to crystallize the ligand-binding domain of the human retinoid X receptor in complex with a variety of newly synthesized ligands. An inverse correlation was observed between the ‘crystallizability’ and the structural dynamics of the various receptor–ligand complexes. Crystallization trials of the human retinoid X receptor α ligand-binding domain (RXRα LBD) in complex with various ligands have been carried out. Using fluorescence anisotropy, it has been found that when compared with agonists these small-molecule effectors enhance the dynamics of the RXRα LBD C-terminal helix H12. In some cases, the mobility of this helix could be dramatically reduced by the addition of a 13-residue co-activator fragment (CoA). In keeping with these observations, crystals have been obtained of the corresponding ternary RXRα LBD–ligand–CoA complexes. In contrast, attempts to crystallize complexes with a highly mobile H12 remained unsuccessful. These experimental observations substantiate the previously recognized role of co-regulator fragments in facilitating the crystallization of nuclear receptor LBDs.

5α-Bile alcohols function as farnesoid X receptor antagonists

International Nuclear Information System (INIS)

Nishimaki-Mogami, Tomoko; Kawahara, Yosuke; Tamehiro, Norimasa; Yoshida, Takemi; Inoue, Kazuhide; Ohno, Yasuo; Nagao, Taku; Une, Mizuho

2006-01-01

The farnesoid X receptor (FXR) is a bile acid/alcohol-activated nuclear receptor that regulates lipid homeostasis. Unlike other steroid receptors, FXR binds bile acids in an orientation that allows the steroid nucleus A to face helix 12 in the receptor, a crucial domain for coactivator-recruitment. Because most naturally occurring bile acids and alcohols contain a cis-oriented A, which is distinct from that of other steroids and cholesterol metabolites, we investigated the role of this 5β-configuration in FXR activation. The results showed that the 5β-(A/B cis) bile alcohols 5β-cyprinol and bufol are potent FXR agonists, whereas their 5α-(A/B trans) counterparts antagonize FXR transactivation and target gene expression. Both isomers bound to FXR, but their ability to induce coactivator-recruitment and thereby induce transactivation differed. These findings suggest a critical role for the A orientation of bile salts in agonist/antagonist function

Regulation of Nampt expression by transcriptional coactivator NCOA6 in pancreatic β-cells

International Nuclear Information System (INIS)

Yoon, Jin; Lee, Kyung Jin; Oh, Gyun-Sik; Kim, Geun Hyang; Kim, Seung-Whan

2017-01-01

Nuclear receptor coactivator 6 (NCOA6) is a transcriptional coactivator and crucial for insulin secretion and glucose metabolism in pancreatic β-cells. However, the regulatory mechanism of β-cell function by NCOA6 is largely unknown. In this study, we found that the transcript levels of nicotinamide phosphoribosyltransferase (Nampt) were decreased in islets of NCOA6 +/− mice compared with NCOA6 +/+ mice. Moreover, NCOA6 overexpression increased the levels of Nampt transcripts in the mouse pancreatic β-cell line NIT-1. Promoter analyses showed that transcriptional activity of the Nampt promoter was stimulated by cooperation of sterol regulatory element binding protein-1c (SREBP-1c) and NCOA6. Additional studies using mutant promoters demonstrated that SREBP-1c activates Nampt promoter through the sterol regulatory element (SRE), but not through the E-box. Using chromatin immunoprecipitation assay, NCOA6 was also shown to be directly recruited to the SRE region of the Nampt promoter. Furthermore, treatment with nicotinamide mononucleotide (NMN), a product of the Nampt reaction and a key NAD + intermediate, ameliorates glucose-stimulated insulin secretion from NCOA6 +/− islets. These results suggest that NCOA6 stimulates insulin secretion, at least partially, by modulating Nampt expression in pancreatic β-cells. - Highlights: • Nampt transcription in β-cells is activated by SREBP-1c through the SRE element. • NCOA6 enhances the transcriptional activity of SREBP-1c in the Nampt promoter. • Defective insulin secretion of NCOA6 +/− islets is recovered by NMN treatment. • NCOA6 is reportedly the first coactivator involved in Nampt expression.

GR and ER co-activation alters the expression of differentiation genes and associates with improved ER+ breast cancer outcome

Science.gov (United States)

West, Diana C.; Pan, Deng; Tonsing-Carter, Eva Y.; Hernandez, Kyle M.; Pierce, Charles F.; Styke, Sarah C.; Bowie, Kathleen R.; Garcia, Tzintzuni I.; Kocherginsky, Masha; Conzen, Suzanne D.

2016-01-01

In estrogen receptor (ER)-negative breast cancer (BC), high tumor glucocorticoid receptor (GR) expression has been associated with a relatively poor outcome. In contrast, using a meta-analysis of several genomic datasets, here we find that tumor GR mRNA expression is associated with improved ER+ relapse-free survival (RFS) (independently of progesterone receptor (PR) expression). To understand the mechanism by which GR expression is associated with a better ER+ BC outcome, the global effect of GR-mediated transcriptional activation in ER+ BC cells was studied. Analysis of GR chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) in ER+/GR+ MCF-7 cells revealed that upon co-activation of GR and ER, GR chromatin association became enriched at proximal promoter regions. Furthermore, following ER activation, increased GR chromatin association was observed at ER, FOXO, and AP1 response elements. In addition, ER associated with GR response elements, suggesting that ER and GR interact in a complex. Co-activation of GR and ER resulted in increased expression (relative to ER activation alone) of transcripts that encode proteins promoting cellular differentiation (e.g. KDM4B, VDR) and inhibiting the Wnt-signaling pathway (IGFBP4). Finally, expression of these individual pro-differentiation genes was associated with significantly improved RFS in ER+ BC patients. Together, these data suggest that the co-expression and subsequent activity of tumor cell GR and ER contribute to the less aggressive natural history of early-stage BC by coordinating the altered expression of genes favoring differentiation. Implications The interaction between estrogen and glucocorticoid receptor activity highlights the importance of context-dependent nuclear receptor function in cancer. PMID:27141101

The Role of Estrogen Related Receptor in Modulating Estrogen Receptor Mediated Transcription in Breast Cancer Cells

Science.gov (United States)

2005-04-01

tumors correlates with an unfavorable prognosis (Ariazi 2002; Lu 2001; Suzuki 2004; Vanacker 1999). The transcriptional activity of ERRa is not inhibited...SA. 101:6570-5. Needham, M ., S. Raines, J. McPheat, C. Stacey, J. Ellston, S. Hoare, and M . Parker. 2000. Differential interaction of steroid hormone...R. Graves, M . Wright, and B.M. Spiegelman. 1998. A cold- inducible coactivator of nuclear receptors linked to adaptive thermogenesis. Cell. 92:829- 39

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

Science.gov (United States)

Vlug, Eva J; van de Ven, Robert A H; Vermeulen, Jeroen F; Bult, Peter; van Diest, Paul J; Derksen, Patrick W B

2013-10-01

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 functions are inhibited by phosphorylation-dependent translocation to the cytosol. YAP overexpression has been associated with different types of cancer, such as lung, skin, prostate, ovary and liver cancer. Recently, YAP was linked to E-cadherin-dependent regulation of contact inhibition in breast cancer cells. In this study we examined YAP protein expression and cellular localization in 237 cases of human invasive breast cancer by immunohistochemistry and related its expression to clinicopathological features and E-cadherin expression. We observed that invasive lobular carcinoma is characterized by higher expression levels of both nuclear and cytosolic YAP (p invasive breast cancer. We observed that high nuclear and cytosolic YAP expression are associated with the E-cadherin deficient breast cancer subtype ILC (p cancers and conditional mouse models of human lobular breast cancer. Since our data indicate that nuclear YAP localization is more common in breast cancers lacking functional adherens junctions, it suggests that YAP-mediated transcription may be involved in the development and progression of invasive lobular breast cancer.

Immunohistochemical localization of steroid receptor coactivators in chondrosarcoma: an in vivo tissue microarray study.

Science.gov (United States)

Li, Wei; Fu, Jingshu; Bian, Chen; Zhang, Jiqiang; Xie, Zhao

2014-12-01

Chondrosarcoma is the second most common type of primary bone malignancy following up osteosarcoma, characterized by resistance to conventional chemotherapeutic agents and radiation regimens. The p160 family members steroid receptor coactivator-1 and -3 (SRC-1 and SRC-3) have been implied in the regulation of cancer growth, migration, invasion, metastasis and chemotherapeutic resistance; but we still lack detailed information about the levels of SRCs in chondrosarcoma. In this study, expression of SRC-1 and SRC-3 in chondrosarcoma was examined by immunohistochemistry with tissue microarrays; the four score system (0, 1, 2 and 3) was used to evaluate the staining. The results showed that there were no gender-, site- or age-differences regarding the expression of SRC-1 or SRC-3 (p>0.05); organ (bone or cartilage) -differences were only detected for SRC-1 but not SRC-3 (pchondrosarcoma, may be novel targets for the prognosis and/or treatment of chondrosarcoma, would have opened a new avenue and established foundation for studying chondrosarcoma. Copyright © 2014 Elsevier GmbH. All rights reserved.

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.

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

International Nuclear Information System (INIS)

Moi, Line L Haugan; Flågeng, Marianne Hauglid; Gjerde, Jennifer; Madsen, Andre; Røst, Therese Halvorsen; Gudbrandsen, Oddrun Anita; Lien, Ernst A; Mellgren, Gunnar

2012-01-01

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. 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. 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 < 0.05). Furthermore, SRC-3/AIB1 and HER-4 were positively correlated with each other and Ets-2 (P < 0.001). The expression of SRCs and HER-2 and -3 is stimulated

The estrogen-related receptors and the adipocyte.

Science.gov (United States)

Carnesecchi, Julie; Vanacker, Jean-Marc

2013-08-01

The estrogen-related receptors (ERRα, β, and γ) are orphan members of the nuclear receptor superfamily. ERRα and γ are highly expressed in tissues displaying elevated energy demands and are involved in several aspects of energetic metabolism, which they regulate mostly in association with members of the PGC-1 coactivator family. These activities have mostly been documented in the liver, heart, or skeletal muscle. ERRα and γ are also highly expressed in adipocytes. Their precise roles in this cell type are less documented, although published data indicate that they contribute to cell differentiation as well as functionality. This review describes these activities.

Epigenetic Basis for the Regulation of Estrogen Receptor Alpha Activity in Breast Cancer Cells

Science.gov (United States)

2009-04-01

Contreras, J.I., Prescott , M.S., Dagenais, S.L., Wu, R., Yee, J., Orringer, M.B., Misek, D.E., Hanash, S.M., et al. (2002). The hepatocyte nuclear... Microbiology . All Rights Reserved. Coactivator Function Defines the Active Estrogen Receptor Alpha Cistrome† Mathieu Lupien,1‡ Jérôme Eeckhoute,1

Biochemical characterization of nuclear receptors for vitamin D3 and glucocorticoids in prostate stroma cell microenvironment

International Nuclear Information System (INIS)

Hidalgo, Alejandro A.; Montecinos, Viviana P.; Paredes, Roberto; Godoy, Alejandro S.; McNerney, Eileen M.; Tovar, Heribelt; Pantoja, Diego; Johnson, Candace; Trump, Donald; Onate, Sergio A.

2011-01-01

Highlights: → Fibroblasts from benign and carcinoma-associated stroma were biochemically characterized for VDR and GR function as transcription factors in prostate stroma cell microenvironment. → Decreased SRC-1/CBP coactivators recruitment to VDR and GR may result in hormone resistance to 1,25D 3 in stromal cell microenvironment prostate cancer. → 1a,25-Dyhidroxyvitamin D 3 (1,25D 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. 1α,25-Dihydroxyvitamin D 3 (1,25D 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 3 is mediated by the 1,25D 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 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 3 action. Conversely, VDR-mediated transcriptional activity was more efficient in 4 out of 13 CAS (30

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, L; Rasmussen, S; 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...... related to this syndrome. The variant was examined, using PCR-RFLP, in the DanMONICA cohort comprising a population-based sample of 2349 subjects. MS was defined using the National Cholesterol Education Program -- Adult Treatment Panel III (NCEP-ATPIII) criteria. The allelic frequency of the Ser482 allele...... and insulin secretion, 24-ambulatory blood pressure or left ventricular mass index. In conclusion, the Gly482Ser polymorphism of the PGC-1alpha gene is not associated with the metabolic syndrome, related quantitative traits or cardiac hypertrophy among Danish Caucasian subjects...

RAC3 nuclear receptor co-activator has a protective role in the apoptosis induced by different stimuli

International Nuclear Information System (INIS)

Colo, Georgina P.; Rubio, Maria F.; Alvarado, Cecilia V.; Costas, Monica A.

2007-01-01

RAC3 belongs to the family of p160 nuclear receptors co activators and it is over-expressed in several tumors. We have previously shown that RAC3 is a NF-κB co activator. In this paper, we investigated the role of RAC3 in cell-sensitivity to apoptosis, using H 2 O 2 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 of RAC3 if compared with the non-tumoral HEK293 cells. The normal or transfected co activator over-expression inhibits apoptosis through a diminished caspase activity and AIF nuclear translocation, increased NF--κB, AKT and p38, and decreased ERK activities. In contrast, inhibition of RAC3 by siRNA induced sensitivity of K562 to TRAIL-induced apoptosis. Such results suggest that over-expression of RAC3 contributes to tumor development through molecular mechanisms that do not depend strictly on acetylation and/or steroid hormones, which control cell death. This could be a possible target for future tumor therapies. (author) [es

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

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

International Nuclear Information System (INIS)

Eisele, Petra Sabine; Furrer, Regula; Beer, Markus; Handschin, Christoph

2015-01-01

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

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.

Muscle Co-activation: Definitions, Mechanisms, and Functions.

Science.gov (United States)

Latash, Mark L

2018-03-28

The phenomenon of agonist-antagonist muscle co-activation is discussed with respect to its consequences for movement mechanics (such as increasing joint apparent stiffness, facilitating faster movements, and effects on action stability), implication for movement optimization, and involvement of different neurophysiological structures. Effects of co-activation on movement stability are ambiguous and depend on the effector representing a kinematic chain with a fixed origin or free origin. Further, co-activation is discussed within the framework of the equilibrium-point hypothesis and the idea of hierarchical control with spatial referent coordinates. Relations of muscle co-activation to changes in one of the basic commands, the c-command, are discussed and illustrated. A hypothesis is suggested that agonist-antagonist co-activation reflects a deliberate neural control strategy to preserve effector-level control and avoid making it degenerate and facing the necessity to control at the level of signals to individual muscles. This strategy, in particular, allows stabilizing motor actions by co-varied adjustments in spaces of control variables. This hypothesis is able to account for higher levels of co-activation in young healthy persons performing challenging tasks and across various populations with movement impairments.

Prognostic and predictive importance of the estrogen receptor coactivator AIB1 in a randomized trial comparing adjuvant letrozole and tamoxifen therapy in postmenopausal breast cancer

DEFF Research Database (Denmark)

Alkner, S; Jensen, Maj-Britt Raaby; Rasmussen, B B

2017-01-01

PURPOSE: To evaluate the estrogen receptor coactivator amplified in breast cancer 1 (AIB1) as a prognostic marker, as well as a predictive marker for response to adjuvant tamoxifen and/or aromatase inhibitors, in early estrogen receptor-positive breast cancer. METHOD: AIB1 was analyzed...... with immunohistochemistry in tissue microarrays of the Danish subcohort (N = 1396) of the International Breast Cancer Study Group's trial BIG 1-98 (randomization between adjuvant tamoxifen versus letrozole versus the sequence of the two drugs). RESULTS: Forty-six percent of the tumors had a high AIB1 expression. In line...... with previous studies, AIB1 correlated to a more aggressive tumor-phenotype (HER2 amplification and a high malignancy grade). High AIB1 also correlated to higher estrogen receptor expression (80-100 vs. 1-79%), and ductal histological type. High AIB1 expression was associated with a poor disease-free survival...

Structure and Dynamics of the Liver Receptor Homolog 1–PGC1 α Complex

Energy Technology Data Exchange (ETDEWEB)

Mays, Suzanne G.; Okafor, C. Denise; Tuntland, Micheal L.; Whitby, Richard J.; Dharmarajan, Venkatasubramanian; Stec, Józef; Griffin, Patrick R.; Ortlund, Eric A.

2017-03-31

Peroxisome proliferator-activated gamma coactivator 1-α (PGC1α) regulates energy metabolism by directly interacting with transcription factors to modulate gene expression. Among the PGC1α binding partners is liver receptor homolog 1 (LRH-1; NR5A2), an orphan nuclear hormone receptor that controls lipid and glucose homeostasis. Although PGC1α is known to bind and activate LRH-1, mechanisms through which PGC1α changes LRH-1 conformation to drive transcription are unknown. Here, we used biochemical and structural methods to interrogate the LRH-1–PGC1α complex. Purified, full-length LRH-1, as well as isolated ligand binding domain, bound to PGC1α with higher affinity than to the coactivator, nuclear receptor coactivator-2 (Tif2), in coregulator peptide recruitment assays. We present the first crystal structure of the LRH-1–PGC1α complex, which depicts several hydrophobic contacts and a strong charge clamp at the interface between these partners. In molecular dynamics simulations, PGC1α induced correlated atomic motion throughout the entire LRH-1 activation function surface, which was dependent on charge-clamp formation. In contrast, Tif2 induced weaker signaling at the activation function surface than PGC1α but promoted allosteric signaling from the helix 6/β-sheet region of LRH-1 to the activation function surface. These studies are the first to probe mechanisms underlying the LRH-1–PGC1α interaction and may illuminate strategies for selective therapeutic targeting of PGC1α-dependent LRH-1 signaling pathways.

Nuclear Receptors, RXR, and the Big Bang.

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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. Copyright © 2014 Elsevier Inc. All rights reserved.

Baicalein suppresses the androgen receptor (AR)-mediated prostate cancer progression via inhibiting the AR N-C dimerization and AR-coactivators interaction.

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Xu, Defeng; Chen, Qiulu; Liu, Yalin; Wen, Xingqiao

2017-12-01

Androgen receptor (AR) plays a critical role in prostate cancer (PCa) development and progression. Androgen deprivation therapy with antiandrogens to reduce androgen biosynthesis or prevent androgens from binding to AR are widely used to suppress AR-mediated PCa growth. However, most of ADT may eventually fail with development of the castration resistance after 12-24 months. Here we found that a natural product baicalein can effectively suppress the PCa progression via targeting the androgen-induced AR transactivation with little effect to AR protein expression. PCa cells including LNCaP, CWR22Rv1, C4-2, PC-3, and DU145, were treated with baicalein and luciferase assay was used to evaluate their effect on the AR transactivation. Cell growth and IC 50 were determined by MTT assay after 48 hrs treatment. RT-PCR was used to evaluate the mRNA levels of AR target genes including PSA, TMPRSS2, and TMEPA1. Western blot was used to determine AR and PSA protein expression. The natural product of baicalein can selectively inhibit AR transactivation with little effect on the other nuclear receptors, including ERα, and GR. At a low concentration, 2.5 μM of baicalein effectively suppresses the growth of AR-positive PCa cells, and has little effect on AR-negative PCa cells. Mechanism dissection suggest that baicalein can suppress AR target genes (PSA, TMPRSS2, and TMEPA1) expression in both androgen responsive LNCaP cells and castration resistant CWR22Rv1 cells, that may involve the inhibiting the AR N/C dimerization and AR-coactivators interaction. Baicalein may be developed as an effective anti-AR therapy via its ability to inhibit AR transactivation and AR-mediated PCa cell growth.

Nuclear receptors and nonalcoholic fatty liver disease1

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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.

2016-01-01

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. Non-alcoholic 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

Isoflavones enhance interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ

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Kojima, Hiroyuki; Takeda, Yukimasa; Muromoto, Ryuta; Takahashi, Miki; Hirao, Toru; Takeuchi, Shinji; Jetten, Anton M.; Matsuda, Tadashi

2018-01-01

The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. In this study, we investigated the effects of isoflavones on RORα/γ activity and the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In doxycycline-inducible CHO stable cell lines, we found that four isoflavones, biochanin A (BA), genistein, formononetin, and daidzein, enhanced RORα- or RORγ-mediated transcriptional activity in a dose-dependent manner. In an activation assay of the Il17a promoter using Jurkat cells, these compounds enhanced the RORα- or RORγ-mediated activation of the Il17a promoter at concentrations of 1 × 10−6 M to 1 × 10−5 M. In mammalian two-hybrid assays, the four isoflavones enhanced the interaction between the RORα- or RORγ-ligand binding domain and the co-activator LXXLL peptide in a dose-dependent manner. In addition, these isoflavones potently enhanced Il17a mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin, but showed slight enhancement of Il17a gene expression in RORα/γ-knockdown EL4 cells. Immunoprecipitation and immunoblotting assays also revealed that BA enhanced the interaction between RORγt and SRC-1, which is a co-activator for nuclear receptors. Taken together, these results suggest that the isoflavones have the ability to enhance IL-17 gene expression by stabilizing the interactions between RORα/γ and co-activators. This also provides the first evidence that dietary chemicals can enhance IL-17 gene expression in immune cells. PMID:25583575

A pp32-retinoblastoma protein complex modulates androgen receptor-mediated transcription and associates with components of the splicing machinery

International Nuclear Information System (INIS)

Adegbola, Onikepe; Pasternack, Gary R.

2005-01-01

We have previously shown pp32 and the retinoblastoma protein interact. pp32 and the retinoblastoma protein are nuclear receptor transcriptional coregulators: the retinoblastoma protein is a coactivator for androgen receptor, the major regulator of prostate cancer growth, while pp32, which is highly expressed in prostate cancer, is a corepressor of the estrogen receptor. We now show pp32 increases androgen receptor-mediated transcription and the retinoblastoma protein modulates this activity. Using affinity purification and mass spectrometry, we identify members of the pp32-retinoblastoma protein complex as PSF and nonO/p54nrb, proteins implicated in coordinate regulation of nuclear receptor-mediated transcription and splicing. We show that the pp32-retinoblastoma protein complex is modulated during TPA-induced K562 differentiation. Present evidence suggests that nuclear receptors assemble multiprotein complexes to coordinately regulate transcription and mRNA processing. Our results suggest that pp32 and the retinoblastoma protein may be part of a multiprotein complex that coordinately regulates nuclear receptor-mediated transcription and mRNA processing

Effects of coumestrol on lipid and glucose metabolism as a farnesoid X receptor ligand

International Nuclear Information System (INIS)

Takahashi, Miki; Kanayama, Tomohiko; Yashiro, Takuya; Kondo, Hidehiko; Murase, Takatoshi; Hase, Tadashi; Tokimitsu, Ichiro; Nishikawa, Jun-ichi; Sato, Ryuichiro

2008-01-01

In the course of an effort to identify novel agonists of the farnesoid X receptor (FXR), coumestrol was determined to be one such ligand. Reporter and in vitro coactivator interaction assays revealed that coumestrol bound and activated FXR. Treatment of Hep G2 cells with coumestrol stimulated the expression of FXR target genes, thereby regulating the expression of target genes of the liver X receptor and hepatocyte nuclear factor-4α. Through these actions, coumestrol is expected to exert beneficial effects on lipid and glucose metabolism

NRSAS: Nuclear Receptor Structure Analysis Servers.

NARCIS (Netherlands)

Bettler, E.J.M.; Krause, R.; Horn, F.; Vriend, G.

2003-01-01

We present a coherent series of servers that can perform a large number of structure analyses on nuclear hormone receptors. These servers are part of the NucleaRDB project, which provides a powerful information system for nuclear hormone receptors. The computations performed by the servers include

Transcriptional activity of Pax3 is co-activated by TAZ

International Nuclear Information System (INIS)

Murakami, Masao; Tominaga, Junji; Makita, Ryosuke; Uchijima, Yasunobu; Kurihara, Yukiko; Nakagawa, Osamu; Asano, Tomoichiro; Kurihara, Hiroki

2006-01-01

Pax3 is a transcription factor which functions in embryonic development and human diseases. In a yeast two-hybrid screen with full-length Pax3 as bait, we isolated a clone encoding transcriptional co-activator with PDZ-binding motif (TAZ) from an E10.5 mouse embryo cDNA library. Co-immunoprecipitation and nuclear co-localization of TAZ with Pax3 suggest that their association is functionally relevant. In situ hybridization revealed TAZ and Pax3 expression to partially overlap in the paraxial mesoderm, limb buds, and the neural tube. In C2C12 myoblast cells and NIH3T3 cells, TAZ enhanced the transcriptional activity of Pax3 on artificial and microphthalmia-associated transcription factor promoter-luciferase constructs, suggesting that TAZ can function as a co-activator of Pax3. Functional interaction between Pax3 and TAZ may provide a clue to clarifying the mechanism by which Pax3 serves as a transcriptional activator during embryogenesis

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

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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.

Crystallographic analysis of murine constitutive androstane receptor ligand-binding domain complexed with 5α-androst-16-en-3α-ol

International Nuclear Information System (INIS)

Vincent, Jeremy; Shan, Li; Fan, Ming; Brunzelle, Joseph S.; Forman, Barry M.; Fernandez, Elias J.

2004-01-01

The purification and structure determination of the murine constitutive androstane receptor bound to its inverse agonist/antagonist androstenol is described. 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

Phenobarbital Meets Phosphorylation of Nuclear Receptors.

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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.

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

Co-activation: its association with weakness and specific neurological pathology

Directory of Open Access Journals (Sweden)

Wiles Charles M

2006-11-01

Full Text Available Abstract Background Net agonist muscle strength is in part determined by the degree of antagonist co-activation. The level of co-activation might vary in different neurological disorders causing weakness or might vary with agonist strength. Aim This study investigated whether antagonist co-activation changed a with the degree of muscle weakness and b with the nature of the neurological lesion causing weakness. Methods Measures of isometric quadriceps and hamstrings strength were obtained. Antagonist (hamstring co-activation during knee extension was calculated as a ratio of hamstrings over quadriceps activity both during an isometric and during a functional sit to stand (STS task (using kinematics in groups of patients with extrapyramidal (n = 15, upper motor neuron (UMN (n = 12, lower motor neuron (LMN with (n = 18 or without (n = 12 sensory loss, primary muscle or neuromuscular junction disorder (n = 17 and in healthy matched controls (n = 32. Independent t-tests or Mann Witney U tests were used to compare between the groups. Correlations between variables were also investigated. Results In healthy subjects mean (SD co-activation of hamstrings during isometric knee extension was 11.8 (6.2% and during STS was 20.5 (12.9%. In patients, co-activation ranged from 7 to 17% during isometric knee extension and 15 to 25% during STS. Only the extrapyramidal group had lower co-activation levels than healthy matched controls (p Conclusion It is concluded that antagonist co-activation does not systematically vary with the site of neurological pathology when compared to healthy matched controls or, in most patient groups, with strength. The lower co-activation levels found in the extrapyramidal group require confirmation and further investigation. Co-activation may be relevant to individuals with muscle weakness. Within patient serial studies in the presence of changing muscle strength may help to understand these relationships more clearly.

The nuclear receptor corepressor has organizational effects within the developing amygdala on juvenile social play and anxiety-like behavior.

Science.gov (United States)

Jessen, Heather M; Kolodkin, Mira H; Bychowski, Meaghan E; Auger, Catherine J; Auger, Anthony P

2010-03-01

Nuclear receptor function on DNA is regulated by the balanced recruitment of coregulatory complexes. Recruited proteins that increase gene expression are called coactivators, and those that decrease gene expression are called corepressors. Little is known about the role of corepressors, such as nuclear receptor corepressor (NCoR), on the organization of behavior. We used real-time PCR to show that NCoR mRNA levels are sexually dimorphic, that females express higher levels of NCoR mRNA within the developing amygdala and hypothalamus, and that NCoR mRNA levels are reduced by estradiol treatment. To investigate the functional role of NCoR on juvenile social behavior, we infused small interfering RNA targeted against NCoR within the developing rat amygdala and assessed the enduring impact on juvenile social play behavior, sociability, and anxiety-like behavior. As expected, control males exhibited higher levels of juvenile social play than control females. Reducing NCoR expression during development further increased juvenile play in males only. Interestingly, decreased NCoR expression within the developing amygdala had lasting effects on increasing juvenile anxiety-like behavior in males and females. These data suggest that the corepressor NCoR functions to blunt sex differences in juvenile play behavior, a sexually dimorphic and hormone-dependent behavior, and appears critical for appropriate anxiety-like behavior in juvenile males and females.

DP97, a DEAD box DNA/RNA helicase, is a target gene-selective co-regulator of the constitutive androstane receptor

International Nuclear Information System (INIS)

Kanno, Yuichiro; Serikawa, Takafumi; Inajima, Jun; Inouye, Yoshio

2012-01-01

Highlights: ► DP97 interacts with nuclear receptor CAR. ► DP97 enhances CAR-mediated transcriptional activation. ► DP97 synergistically enhances transactivity of CAR by the co-expression of SRC-1 or PGC1α. ► DP97 is a gene-selective co-activator for hCAR. -- Abstract: 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 DP97, a member of the DEAD box DNA/RNA helicase protein family, is a novel CAR-interacting protein. Using HepG2 cells expressing human CAR in the presence of tetracycline, we showed that knockdown of DP97 with small interfering RNAs suppressed tetracycline-inducible mRNA expression of CYP2B6 and UGT1A1 but not CYP3A4. Thus, DP97 was found to be a gene (or promoter)-selective co-activator for hCAR. DP97-mediated CAR transactivation was synergistically enhanced by the co-expression of SRC-1 or PGC1α, therefore it might act as mediator between hCAR and appropriate co-activators.

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

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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.

TRIM32 promotes retinoic acid receptor α-mediated differentiation in human promyelogenous leukemic cell line HL60

International Nuclear Information System (INIS)

Sato, Tomonobu; Okumura, Fumihiko; Iguchi, Akihiro; Ariga, Tadashi; Hatakeyama, Shigetsugu

2012-01-01

Highlights: ► TRIM32 enhanced RARα-mediated transcriptional activity even in the absence of RA. ► TRIM32 stabilized RARα in the human promyelogenous leukemic cell line HL60. ► Overexpression of TRIM32 in HL60 cells induced granulocytic differentiation. ► TRIM32 may function as a coactivator for RARα-mediated transcription in APL cells. -- Abstract: Ubiquitination, one of the posttranslational modifications, appears to be involved in the transcriptional activity of nuclear receptors including retinoic acid receptor α (RARα). We previously reported that an E3 ubiquitin ligase, TRIM32, interacts with several important proteins including RARα and enhances transcriptional activity of RARα in mouse neuroblastoma cells and embryonal carcinoma cells. Retinoic acid (RA), which acts as a ligand to nuclear receptors including RARα, plays crucial roles in development, differentiation, cell cycles and apoptosis. In this study, we found that TRIM32 enhances RARα-mediated transcriptional activity even in the absence of RA and stabilizes RARα in the human promyelogenous leukemic cell line HL60. Moreover, we found that overexpression of TRIM32 in HL60 cells suppresses cellular proliferation and induces granulocytic differentiation even in the absence of RA. These findings suggest that TRIM32 functions as one of the coactivators for RARα-mediated transcription in acute promyelogenous leukemia (APL) cells, and thus TRIM32 may become a potentially therapeutic target for APL.

Dynamic regulation of Drosophila nuclear receptor activity in vivo.

Science.gov (United States)

Palanker, Laura; Necakov, Aleksandar S; Sampson, Heidi M; Ni, Ruoyu; Hu, Chun; Thummel, Carl S; Krause, Henry M

2006-09-01

Nuclear receptors are a large family of transcription factors that play major roles in development, metamorphosis, metabolism and disease. To determine how, where and when nuclear receptors are regulated by small chemical ligands and/or protein partners, we have used a 'ligand sensor' system to visualize spatial activity patterns for each of the 18 Drosophila nuclear receptors in live developing animals. Transgenic lines were established that express the ligand binding domain of each nuclear receptor fused to the DNA-binding domain of yeast GAL4. When combined with a GAL4-responsive reporter gene, the fusion proteins show tissue- and stage-specific patterns of activation. We show that these responses accurately reflect the presence of endogenous and exogenously added hormone, and that they can be modulated by nuclear receptor partner proteins. The amnioserosa, yolk, midgut and fat body, which play major roles in lipid storage, metabolism and developmental timing, were identified as frequent sites of nuclear receptor activity. We also see dynamic changes in activation that are indicative of sweeping changes in ligand and/or co-factor production. The screening of a small compound library using this system identified the angular psoralen angelicin and the insect growth regulator fenoxycarb as activators of the Ultraspiracle (USP) ligand-binding domain. These results demonstrate the utility of this system for the functional dissection of nuclear receptor pathways and for the development of new receptor agonists and antagonists that can be used to modulate metabolism and disease and to develop more effective means of insect control.

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.

DP97, a DEAD box DNA/RNA helicase, is a target gene-selective co-regulator of the constitutive androstane receptor

Energy Technology Data Exchange (ETDEWEB)

Kanno, Yuichiro, E-mail: ykanno@phar.toho-u.ac.jp [Faculty of Pharmaceutical Sciences, Toho University, Chiba (Japan); Serikawa, Takafumi; Inajima, Jun; Inouye, Yoshio [Faculty of Pharmaceutical Sciences, Toho University, Chiba (Japan)

2012-09-14

Highlights: Black-Right-Pointing-Pointer DP97 interacts with nuclear receptor CAR. Black-Right-Pointing-Pointer DP97 enhances CAR-mediated transcriptional activation. Black-Right-Pointing-Pointer DP97 synergistically enhances transactivity of CAR by the co-expression of SRC-1 or PGC1{alpha}. Black-Right-Pointing-Pointer DP97 is a gene-selective co-activator for hCAR. -- Abstract: 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 DP97, a member of the DEAD box DNA/RNA helicase protein family, is a novel CAR-interacting protein. Using HepG2 cells expressing human CAR in the presence of tetracycline, we showed that knockdown of DP97 with small interfering RNAs suppressed tetracycline-inducible mRNA expression of CYP2B6 and UGT1A1 but not CYP3A4. Thus, DP97 was found to be a gene (or promoter)-selective co-activator for hCAR. DP97-mediated CAR transactivation was synergistically enhanced by the co-expression of SRC-1 or PGC1{alpha}, therefore it might act as mediator between hCAR and appropriate co-activators.

Analysis of PGC-1α variants Gly482Ser and Thr612Met concerning their PPARγ2-coactivation function

International Nuclear Information System (INIS)

Nitz, Inke; Ewert, Agnes; Klapper, Maja; Doering, Frank

2007-01-01

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a cofactor involved in adaptive thermogenesis, fatty acid oxidation, and gluconeogenesis. Dysfunctions of this protein are likely to contribute to the development of obesity and the metabolic syndrome. This is in part but not definitely confirmed by results of population studies. The aim of this study was to investigate if common genetic variants rs8192678 (Gly482Ser) and rs3736265 (Thr612Met) in the PGC-1α gene lead to a functional consequence in cofactor activity using peroxisome proliferator-activated receptor-γ 2 (PPARγ2) as interacting transcription factor. Reporter gene assays in HepG2 cells with wildtype and mutant proteins of both PGC1α and PPARγ2 (Pro12Ala, rs1801282) using the acyl-CoA-binding protein (ACBP) promoter showed no difference in coactivator activity. This is First study implicating that the Gly482Ser and Thr612Met polymorphisms in PGC-1α and Pro12Ala polymorphism in PPARγ2 do not affect the functional integrity of these proteins

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.

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.

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.

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...

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.

Selective estrogen receptor modulators (SERMs): Mechanisms of anticarcinogenesis and drug resistance

Energy Technology Data Exchange (ETDEWEB)

Lewis, Joan S. [Fox Chase Cancer Center, Alfred G. Knudson Chair of Cancer Research, 333 Cottman Avenue, Philadelphia, PA 19111 (United States); Jordan, V. Craig [Fox Chase Cancer Center, Alfred G. Knudson Chair of Cancer Research, 333 Cottman Avenue, Philadelphia, PA 19111 (United States)]. E-mail: v.craig.jordan@fccc.edu

2005-12-11

Despite the beneficial effects of estrogens in women's health, there is a plethora of evidence that suggest an important role for these hormones, particularly 17{beta}-estradiol (E{sub 2}), in the development and progression of breast cancer. Most estrogenic responses are mediated by estrogen receptors (ERs), either ER{alpha} or ER{beta}, which are members of the nuclear receptor superfamily of ligand-dependent transcription factors. Selective estrogen receptor modulators (SERMs) are ER ligands that in some tissues (i.e. bone and cardiovascular system) act like estrogens but block estrogen action in others. Tamoxifen is the first SERM that has been successfully tested for the prevention of breast cancer in high-risk women and is currently approved for the endocrine treatment of all stages of ER-positive breast cancer. Raloxifene, a newer SERM originally developed for osteoporosis, also appears to have preventive effect on breast cancer incidence. Numerous studies have examined the molecular mechanisms for the tissue selective action of SERMs, and collectively they indicate that different ER ligands induce distinct conformational changes in the receptor that influence its ability to interact with coregulatory proteins (i.e. coactivators and corepressors) critical for the regulation of target gene transcription. The relative expression of coactivators and corepressors, and the nature of the ER and its target gene promoter also affect SERM biocharacter. This review summarizes the therapeutic application of SERMs in medicine; particularly breast cancer, and highlights the emerging understanding of the mechanism of action of SERMs in select target tissues, and the inevitable development of resistance.

Nuclear Receptors in atherosclerosis: a superfamily with many 'Goodfellas'

NARCIS (Netherlands)

Kurakula, Kondababu; Hamers, Anouk A. J.; de Waard, Vivian; de Vries, Carlie J. M.

2013-01-01

Nuclear Receptors form a superfamily of 48 transcription factors that exhibit a plethora of functions in steroid hormone signaling, regulation of metabolism, circadian rhythm and cellular differentiation. In this review, we describe our current knowledge on the role of Nuclear Receptors in

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...

Characterization of a novel non-steroidal glucocorticoid receptor antagonist

Energy Technology Data Exchange (ETDEWEB)

Li, Qun-Yi; Zhang, Meng [The National Center for Drug Screening, Shanghai (China); State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China); Hallis, Tina M.; DeRosier, Therese A. [Cell Systems Division, Invitrogen, Madison, WI (United States); Yue, Jian-Min; Ye, Yang [State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China); Mais, Dale E. [The National Center for Drug Screening, Shanghai (China); MPI Research, Mattawan, MI (United States); Wang, Ming-Wei, E-mail: wangmw@mail.shcnc.ac.cn [The National Center for Drug Screening, Shanghai (China); State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China)

2010-01-15

Selective antagonists of the glucocorticoid receptor (GR) are desirable for the treatment of hypercortisolemia associated with Cushing's syndrome, psychic depression, obesity, diabetes, neurodegenerative diseases, and glaucoma. NC3327, a non-steroidal small molecule with potent binding affinity to GR (K{sub i} = 13.2 nM), was identified in a high-throughput screening effort. As a full GR antagonist, NC3327 greatly inhibits the dexamethasone (Dex) induction of marker genes involved in hepatic gluconeogenesis, but has a minimal effect on matrix metalloproteinase 9 (MMP-9), a GR responsive pro-inflammatory gene. Interestingly, the compound recruits neither coactivators nor corepressors to the GR complex but competes with glucocorticoids for the interaction between GR and a coactivator peptide. Moreover, NC3327 does not trigger GR nuclear translocation, but significantly blocks Dex-induced GR transportation to the nucleus, and thus appears to be a 'competitive' GR antagonist. Therefore, the non-steroidal compound, NC3327, may represent a new class of GR antagonists as potential therapeutics for a variety of cortisol-related endocrine disorders.

Characterization of a novel non-steroidal glucocorticoid receptor antagonist

International Nuclear Information System (INIS)

Li, Qun-Yi; Zhang, Meng; Hallis, Tina M.; DeRosier, Therese A.; Yue, Jian-Min; Ye, Yang; Mais, Dale E.; Wang, Ming-Wei

2010-01-01

Selective antagonists of the glucocorticoid receptor (GR) are desirable for the treatment of hypercortisolemia associated with Cushing's syndrome, psychic depression, obesity, diabetes, neurodegenerative diseases, and glaucoma. NC3327, a non-steroidal small molecule with potent binding affinity to GR (K i = 13.2 nM), was identified in a high-throughput screening effort. As a full GR antagonist, NC3327 greatly inhibits the dexamethasone (Dex) induction of marker genes involved in hepatic gluconeogenesis, but has a minimal effect on matrix metalloproteinase 9 (MMP-9), a GR responsive pro-inflammatory gene. Interestingly, the compound recruits neither coactivators nor corepressors to the GR complex but competes with glucocorticoids for the interaction between GR and a coactivator peptide. Moreover, NC3327 does not trigger GR nuclear translocation, but significantly blocks Dex-induced GR transportation to the nucleus, and thus appears to be a 'competitive' GR antagonist. Therefore, the non-steroidal compound, NC3327, may represent a new class of GR antagonists as potential therapeutics for a variety of cortisol-related endocrine disorders.

Co regulation of srGAP1 by Wnt and androgen receptor signaling: a new target for treatment of CRPC

Science.gov (United States)

2016-12-01

and TCF/LEFs, but also can adopt an α-helical conformation for nuclear receptor binding proteins [33]. Using a yeast two-hybrid system, Yang et al...It has been suggested that AR signaling in CRPC is sus- tained by development of AR amplication, mutation , alternate spilcing, and several alter...addition, β-catenin can function as a coactivator with altered ARs with mutations W741C and T877A in prostate cancer cell lines [33]. These AR

The role of oestrogen receptor {alpha} in human thyroid cancer: contributions from coregulatory proteins and the tyrosine kinase receptor HER2.

LENUS (Irish Health Repository)

Kavanagh, Dara O

2012-02-01

Epidemiological, clinical, and molecular studies suggest a role for oestrogen in thyroid cancer. How oestrogen mediates its effects and the consequence of it on clinical outcome has not been fully elucidated. The participation of coregulatory proteins in modulating oestrogen receptor (ER) function and input of crosstalk with the tyrosine kinase receptor HER2 was investigated. Oestrogen induced cell proliferation in the follicular thyroid cancer (FTC)-133 cells, but not in the anaplastic 8305C cell line. Knockdown of the coactivator steroid receptor coactivator (SRC)-1 inhibited FTC-133 basal, but not oestrogen induced, cell proliferation. Oestrogen also increased protein expression of SRC-1 and the ER target gene cyclin D1 in the FTC-133 cell line. ERalpha, ERbeta, the coregulatory proteins SRC-1 and nuclear corepressor (NCoR), and the tyrosine kinase receptor HER2 were localised by immunohistochemistry and immnofluorescence in paraffin-embedded tissue from thyroid tumour patients (n=111). ERalpha was colocalised with both SRC-1 and NCoR to the nuclei of the tumour epithelial cells. Expression of ERalpha and NCoR was found predominantly in non-anaplastic tumours and was significantly associated with well-differentiated tumours and reduced incidence of disease recurrence. In non-anaplastic tumours, HER2 was significantly associated with SRC-1, and these proteins were associated with poorly differentiated tumours, capsular invasion and disease recurrence. Totally, 87% of anaplastic tumours were positive for SRC-1. Kaplan-Meier estimates of disease-free survival indicated that in thyroid cancer, SRC-1 strongly correlates with reduced disease-free survival (P<0.001), whereas NCoR predicted increased survival (P<0.001). These data suggest opposing roles for the coregulators SRC-1 and NCoR in thyroid tumour progression.

Effect of Knee Joint Angle and Contraction Intensity on Hamstrings Coactivation.

Science.gov (United States)

Wu, Rui; Delahunt, Eamonn; Ditroilo, Massimiliano; Lowery, Madeleine M; DE Vito, Giuseppe

2017-08-01

This study investigated the effect of knee joint angle and contraction intensity on the coactivation of the hamstring muscles (when acting as antagonists to the quadriceps) in young and older individuals of both sexes. A total of 25 young (24 ± 2.6 yr) and 26 older (70 ± 2.5 yr) healthy men and women participated. Maximal voluntary isometric contraction of the knee extensors and flexors was assessed at two knee joint angles (90° and 60°, 0° = full extension). At each angle, participants performed submaximal contractions of the knee extensors (20%, 50%, and 80% maximal voluntary isometric contraction), whereas surface EMG was simultaneously acquired from the vastus lateralis and biceps femoris muscles to assess the level (EMG root-mean-square) of agonist activation and antagonist coactivation. Subcutaneous adipose tissue in the areas corresponding to surface EMG electrode placements was measured via ultrasonography. The contractions performed at 90° knee flexion demonstrated higher levels of antagonist coactivation (all P < 0.01) and agonist activation (all P < 0.01) as a function of contraction intensity compared with the 60° knee flexion. Furthermore, after controlling for subcutaneous adipose tissue, older participants exhibited a higher level of antagonist coactivation at 60° knee flexion compared with young participants (P < 0.05). The results of the present study suggest that 1) the antagonist coactivation is dependent on knee joint angle and contraction intensity and 2) subcutaneous adipose tissue may affect the measured coactivation level likely because of a cross-talk effect. Antagonist coactivation may play a protective role in stabilizing the knee joint and maintaining constant motor output.

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.

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.

Flightless I (Drosophila) homolog facilitates chromatin accessibility of the estrogen receptor α target genes in MCF-7 breast cancer cells

Energy Technology Data Exchange (ETDEWEB)

Jeong, Kwang Won, E-mail: kwjeong@gachon.ac.kr

2014-04-04

Highlights: • H3K4me3 and Pol II binding at TFF1 promoter were reduced in FLII-depleted MCF-7 cells. • FLII is required for chromatin accessibility of the enhancer of ERalpha target genes. • Depletion of FLII causes inhibition of proliferation of MCF-7 cells. - Abstract: The coordinated activities of multiple protein complexes are essential to the remodeling of chromatin structure and for the recruitment of RNA polymerase II (Pol II) to the promoter in order to facilitate the initiation of transcription in nuclear receptor-mediated gene expression. Flightless I (Drosophila) homolog (FLII), a nuclear receptor coactivator, is associated with the SWI/SNF-chromatin remodeling complex during estrogen receptor (ER)α-mediated transcription. However, the function of FLII in estrogen-induced chromatin opening has not been fully explored. Here, we show that FLII plays a critical role in establishing active histone modification marks and generating the open chromatin structure of ERα target genes. We observed that the enhancer regions of ERα target genes are heavily occupied by FLII, and histone H3K4me3 and Pol II binding induced by estrogen are decreased in FLII-depleted MCF-7 cells. Furthermore, formaldehyde-assisted isolation of regulatory elements (FAIRE)-quantitative polymerase chain reaction (qPCR) experiments showed that depletion of FLII resulted in reduced chromatin accessibility of multiple ERα target genes. These data suggest FLII as a key regulator of ERα-mediated transcription through its role in regulating chromatin accessibility for the binding of RNA Polymerase II and possibly other transcriptional coactivators.

Flightless I (Drosophila) homolog facilitates chromatin accessibility of the estrogen receptor α target genes in MCF-7 breast cancer cells

International Nuclear Information System (INIS)

Jeong, Kwang Won

2014-01-01

Highlights: • H3K4me3 and Pol II binding at TFF1 promoter were reduced in FLII-depleted MCF-7 cells. • FLII is required for chromatin accessibility of the enhancer of ERalpha target genes. • Depletion of FLII causes inhibition of proliferation of MCF-7 cells. - Abstract: The coordinated activities of multiple protein complexes are essential to the remodeling of chromatin structure and for the recruitment of RNA polymerase II (Pol II) to the promoter in order to facilitate the initiation of transcription in nuclear receptor-mediated gene expression. Flightless I (Drosophila) homolog (FLII), a nuclear receptor coactivator, is associated with the SWI/SNF-chromatin remodeling complex during estrogen receptor (ER)α-mediated transcription. However, the function of FLII in estrogen-induced chromatin opening has not been fully explored. Here, we show that FLII plays a critical role in establishing active histone modification marks and generating the open chromatin structure of ERα target genes. We observed that the enhancer regions of ERα target genes are heavily occupied by FLII, and histone H3K4me3 and Pol II binding induced by estrogen are decreased in FLII-depleted MCF-7 cells. Furthermore, formaldehyde-assisted isolation of regulatory elements (FAIRE)-quantitative polymerase chain reaction (qPCR) experiments showed that depletion of FLII resulted in reduced chromatin accessibility of multiple ERα target genes. These data suggest FLII as a key regulator of ERα-mediated transcription through its role in regulating chromatin accessibility for the binding of RNA Polymerase II and possibly other transcriptional coactivators

Nuclear triiodothyronine receptor binding characteristics and occupancy in obese (ob/ob) mice

International Nuclear Information System (INIS)

Hillgartner, F.B.; Romsos, D.R.

1987-01-01

Obese (ob/ob) mice exhibit reduced adaptive thermogenesis associated with an impairment of thyroid hormone action. The mechanism underlying the latter defect was investigated by comparing the binding characteristics and occupancy of solubilized nuclear 3,5,3'-triiodothyronine (T 3 ) receptors from livers of lean and obese mice. T 3 concentration was measured by radioimmunoassay. Scatchard analysis showed minimal differences in B/sub max/ and K/sub d/ between phenotypes at both 4 and 8-10 wk of age, indicating that reduced hepatic thyroid hormone expression in obese mice is not caused by alterations in nuclear receptor concentration or affinity. In contrast, nuclear T 3 receptor occupancy (endogenous T 3 associated with the specific receptor divided by B/sub max/) was 14 and 23% lower in 4- and 8- to 10-wk old obese mice, respectively. Together with reported changes in hepatic thyroid hormone-sensitive enzymes, these data are consistent with a diminished nuclear T 3 signal initiating thyroid hormone action in obese mice. Decreased nuclear T 3 receptor occupancy may be secondary to a low transport of plasma T 3 to the nuclear pool. In conclusion, impaired hepatic thyroid hormone action in obese mice is mediated in part at least by a reduction in nuclear T 3 receptor occupancy

The association between antagonist hamstring coactivation and episodes of knee joint shifting and buckling.

Science.gov (United States)

Segal, N A; Nevitt, M C; Welborn, R D; Nguyen, U-S D T; Niu, J; Lewis, C E; Felson, D T; Frey-Law, L

2015-07-01

Hamstring coactivation during quadriceps activation is necessary to counteract the quadriceps pull on the tibia, but coactivation can be elevated with symptomatic knee osteoarthritis (OA). To guide rehabilitation to attenuate risk for mobility limitations and falls, this study evaluated whether higher antagonistic open kinetic chain hamstring coactivation is associated with knee joint buckling (sudden loss of support) and shifting (a sensation that the knee might give way). At baseline, median hamstring coactivation was assessed during maximal isokinetic knee extensor strength testing and at baseline and 24-month follow-up, knee buckling and shifting was self-reported. Associations between tertiles of co-activation and knee (1) buckling, (2) shifting and (3) either buckling or shifting were assessed using logistic regression, adjusted for age, sex, knee OA and pain. 1826 participants (1089 women) were included. Mean ± SD age was 61.7 ± 7.7 years, BMI was 30.3 ± 5.5 kg/m(2) and 38.2% of knees had OA. There were no consistent statistically significant associations between hamstring coactivation and ipsilateral prevalent or incident buckling or the combination of buckling and shifting. The odds ratios for incident shifting in the highest in comparison with the lowest tertile of coactivation had similar magnitudes in the combined and medial hamstrings, but only reached statistical significance for lateral hamstring coactivation, OR(95%CI) 1.53 (0.99, 2.36). Hamstring coactivation during an open kinetic chain quadriceps exercise was not consistently associated with prevalent or incident self-reported knee buckling or shifting in older adults with or at risk for knee OA. Copyright © 2015. Published by Elsevier Ltd.

Coactivator PGC-1α regulates the fasting inducible xenobiotic-metabolizing enzyme CYP2A5 in mouse primary hepatocytes

International Nuclear Information System (INIS)

Arpiainen, Satu; Jaervenpaeae, Sanna-Mari; Manninen, Aki; Viitala, Pirkko; Lang, Matti A.; Pelkonen, Olavi; Hakkola, Jukka

2008-01-01

The nutritional state of organisms and energy balance related diseases such as diabetes regulate the metabolism of xenobiotics such as drugs, toxins and carcinogens. However, the mechanisms behind this regulation are mostly unknown. The xenobiotic-metabolizing cytochrome P450 (CYP) 2A5 enzyme has been shown to be induced by fasting and by glucagon and cyclic AMP (cAMP), which mediate numerous fasting responses. Peroxisome proliferator-activated receptor γ coactivator (PGC)-1α triggers many of the important hepatic fasting effects in response to elevated cAMP levels. In the present study, we were able to show that cAMP causes a coordinated induction of PGC-1α and CYP2A5 mRNAs in murine primary hepatocytes. Furthermore, the elevation of the PGC-1α expression level by adenovirus mediated gene transfer increased CYP2A5 transcription. Co-transfection of Cyp2a5 5' promoter constructs with the PGC-1α expression vector demonstrated that PGC-1α is able to activate Cyp2a5 transcription through the hepatocyte nuclear factor (HNF)-4α response element in the proximal promoter of the Cyp2a5 gene. Chromatin immunoprecipitation assays showed that PGC-1α binds, together with HNF-4α, to the same region at the Cyp2a5 proximal promoter. In conclusion, PGC-1α mediates the expression of CYP2A5 induced by cAMP in mouse hepatocytes through coactivation of transcription factor HNF-4α. This strongly suggests that PGC-1α is the major factor mediating the fasting response of CYP2A5

Effect of higher muscle coactivation on standing postural response to perturbation in older adults.

Science.gov (United States)

Nagai, Koutatsu; Okita, Yusuke; Ogaya, Shinya; Tsuboyama, Tadao

2017-04-01

Although several studies have reported that muscle coactivation during postural control increases with age, the effect of higher muscle coactivation on standing postural response to perturbation is unknown. To investigate whether higher muscle coactivation affects standing postural response to perturbation in older adults. Thirty-four community-dwelling older participants were randomly assigned either to the coactivation group (CG), where muscle coactivation was increased intentionally, or to the non-coactivation group (NCG). The participants were instructed to stand on a force plate that moved forward or backward. Electromyography data were collected from the lower leg muscles. We requested the participants in the CG to increase the activity of their tibialis anterior, and to maintain this posture during the tasks. We moved the force plate with a constant amplitude and velocity, and measured kinematic data with a camera during the tasks. During forward transfer, the knee extension and hip flexion decreased in the CG after perturbation compared to NCG, and the trunk extension angle increased. The center of pressure (COP) displacement decreased around the peak of the movement in the CG compared to NCG. During backward transfer, ankle dorsal and knee flexion changed after perturbation in the CG compared to NCG. Our study found that higher muscle coactivation inhibits lower limb and COP movement as well as increases trunk tilt and the risk for falls during forward perturbations. Postural control with higher coactivation appears to be inefficient for maintaining balance during the backward sway of posture.

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

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

International Nuclear Information System (INIS)

Haiman, Christopher A; Stallcup, Michael R; Greene, Geoffrey L; Press, Michael F; Garcia, Rachel R; Hsu, Chris; Xia, Lucy; Ha, Helen; Sheng, Xin; Le Marchand, Loic; Kolonel, Laurence N; Henderson, Brian E

2009-01-01

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. 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. 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 studies. Our findings suggest that common coding

Acceleration of the glycolytic flux by steroid receptor coactivator-2 is essential for endometrial decidualization.

Directory of Open Access Journals (Sweden)

Ramakrishna Kommagani

2013-10-01

Full Text Available Early embryo miscarriage is linked to inadequate endometrial decidualization, a cellular transformation process that enables deep blastocyst invasion into the maternal compartment. Although much of the cellular events that underpin endometrial stromal cell (ESC decidualization are well recognized, the individual gene(s and molecular pathways that drive the initiation and progression of this process remain elusive. Using a genetic mouse model and a primary human ESC culture model, we demonstrate that steroid receptor coactivator-2 (SRC-2 is indispensable for rapid steroid hormone-dependent proliferation of ESCs, a critical cell-division step which precedes ESC terminal differentiation into decidual cells. We reveal that SRC-2 is required for increasing the glycolytic flux in human ESCs, which enables rapid proliferation to occur during the early stages of the decidualization program. Specifically, SRC-2 increases the glycolytic flux through induction of 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 3 (PFKFB3, a major rate-limiting glycolytic enzyme. Similarly, acute treatment of mice with a small molecule inhibitor of PFKFB3 significantly suppressed the ability of these animals to exhibit an endometrial decidual response. Together, these data strongly support a conserved mechanism of action by which SRC-2 accelerates the glycolytic flux through PFKFB3 induction to provide the necessary bioenergy and biomass to meet the demands of a high proliferation rate observed in ESCs prior to their differentiation into decidual cells. Because deregulation of endometrial SRC-2 expression has been associated with common gynecological disorders of reproductive-age women, this signaling pathway, involving SRC-2 and PFKFB3, promises to offer new clinical approaches in the diagnosis and/or treatment of a non-receptive uterus in patients presenting idiopathic infertility, recurrent early pregnancy loss, or increased time to pregnancy.

Incremental change in the set of coactive cortical assemblies enables mental continuity.

Science.gov (United States)

Reser, Jared Edward

2016-12-01

This opinion article explores how sustained neural firing in association areas allows high-order mental representations to be coactivated over multiple perception-action cycles, permitting sequential mental states to share overlapping content and thus be recursively interrelated. The term "state-spanning coactivity" (SSC) is introduced to refer to neural nodes that remain coactive as a group over a given period of time. SSC ensures that contextual groupings of goal or motor-relevant representations will demonstrate continuous activity over a delay period. It also allows potentially related representations to accumulate and coactivate despite delays between their initial appearances. The nodes that demonstrate SSC are a subset of the active representations from the previous state, and can act as referents to which newly introduced representations of succeeding states relate. Coactive nodes pool their spreading activity, converging on and activating new nodes, adding these to the remaining nodes from the previous state. Thus, the overall distribution of coactive nodes in cortical networks evolves gradually during contextual updating. The term "incremental change in state-spanning coactivity" (icSSC) is introduced to refer to this gradual evolution. Because a number of associated representations can be sustained continuously, each brain state is embedded recursively in the previous state, amounting to an iterative process that can implement learned algorithms to progress toward a complex result. The longer representations are sustained, the more successive mental states can share related content, exhibit progressive qualities, implement complex algorithms, and carry thematic or narrative continuity. Included is a discussion of the implications that SSC and icSSC may have for understanding working memory, defining consciousness, and constructing AI architectures. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

Fiscal 1998 achievement report on regional consortium research and development project. Venture business raising type regional consortium - small business creating base type (Control of gene expression by ligands for nuclear receptors and its application to medicine manufacture - 2nd year); 1998 nendo kakunai juyotai ligand ni yoru iden joho hatsugen no seigyo to iyaku seizo process eno oyo seika hokokusho. 2

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Studies are made about ascochlorin and its derivatives which are expected to be effective in the treatment and prevention of lifestyle diseases such as arteriosclerosis, diabetes, hypertension, etc. The current goal is to definitely prove at the cell culture stage that ascochlorin and its derivatives act as ligands for nuclear receptors. As the result of the effort to prove their activation of nuclear receptors, it is clarified that they activate not only PPARr, which is the initial target of the research, but also PPARa, PXR, and ER. A computer simulation of interaction between ascochlorin derivatives and PPARr is conducted, and now it is predicted that the helix 10 cubic structure is transformed so that co-activators may connect to the structure. It is also found that AS-6 inhibits almost completely the appearance of type II diabetes in the db/db mouse lacking leptin receptors and type I diabetes in the NOD (non-obese diabetes) mouse. (NEDO)

β-Carotene-9′,10′-Oxygenase Status Modulates the Impact of Dietary Tomato and Lycopene on Hepatic Nuclear Receptor–, Stress-, and Metabolism-Related Gene Expression in Mice123

Science.gov (United States)

Tan, Hsueh-Li; Moran, Nancy E.; Cichon, Morgan J.; Riedl, Ken M.; Schwartz, Steven J.; Erdman, John W.; Pearl, Dennis K.; Thomas-Ahner, Jennifer M.; Clinton, Steven K.

2014-01-01

Tomato and lycopene (ψ, ψ-carotene) consumption is hypothesized to protect against nonalcoholic steatohepatitis and hepatocarcinogenesis, processes that may depend upon diet and gene interactions. To investigate the interaction of tomato or lycopene feeding with β-carotene-9′,10′-monooxygenase (Bco2) on hepatic metabolic and signaling pathways, male wild-type (WT) and Bco2−/− mice (3-wk-old; n = 36) were fed semi-purified control, 10% tomato powder–containing, or 0.25% lycopene beadlet–containing diets for 3 wk. Serum lycopene concentrations were higher in lycopene- and tomato-fed Bco2−/− mice compared with WT (P = 0.03). Tomato- and lycopene-fed mice had detectable hepatic apolipoprotein (apo)-6′-, apo-8′-, and apo-12′-lycopenal concentrations. Hepatic expression of β-carotene-15,15’-monooxygenase was increased in Bco2−/− mice compared with WT (P = 0.02), but not affected by diet. Evaluation of hepatic gene expression by focused quantitative reverse transcriptase-polymerase chain reaction arrays for nuclear receptors and coregulators (84 genes) and stress and metabolism (82 genes) genes indicates that tomato feeding affected 31 genes (≥1.5-fold, P lycopene feeding affected 19 genes, 16 of which were affected by both diets. Lycopene down-regulation of 7 nuclear receptors and coregulators, estrogen-related receptor-α, histone deacetylase 3, nuclear receptor coactivator 4, RevErbA-β, glucocorticoid receptor, peroxisome proliferator-activated receptor (PPAR)-α, and PPAR-γ, coactivator 1 β was dependent upon interaction with Bco2 status. Lycopene and tomato feeding induced gene expression patterns consistent with decreased lipid uptake, decreased cell proliferation and mitosis, down-regulated aryl hydrocarbon receptor signaling, and decreased expression of genes involved in retinoid X receptor heterodimer activation. Tomato feeding also caused expression changes consistent with down-regulation of DNA synthesis and terpenoid

Comparison of solubilized and purified plasma membrane and nuclear insulin receptors

International Nuclear Information System (INIS)

Wong, K.Y.; Hawley, D.; Vigneri, R.; Goldfine, I.D.

1988-01-01

Prior studies have detected biochemical and immunological differences between insulin receptors in plasma membranes and isolated nuclei. To further investigate these receptors, they were solubilized in Triton X-100 partially purified by wheat germ agglutinin-agarose chromatography. In these preparations, the nuclear and plasma membrane receptors had very similar pH optima (pH 8.0) and reactivities to a group of polyclonal antireceptor antibodies. Further, both membrane preparations had identical binding activities when labeled insulin was competed for by unlabeled insulin (50% inhibition at 800 pM). Next, nuclear and plasma membranes were solubilized and purified to homogeneity by wheat germ agglutinin-agarose and insulin-agarose chromatography. In both receptors, labeled insulin was covalently cross-linked to a protein of 130 kilodaltons representing the insulin receptor α subunit. When preparations of both receptors were incubated with insulin and then adenosine 5'-[γ- 32 P]triphosphate, a protein of 95 kilodaltons representing the insulin receptor β subunit was phosphorylated in a dose-dependent manner. These studies indicate, therefore, that solubilized plasma membrane and nuclear insulin receptors have similar structures and biochemical properties, and they suggest that they are the same (or very similar) proteins

NR4A nuclear receptors are orphans but not lonesome.

Science.gov (United States)

Kurakula, Kondababu; Koenis, Duco S; van Tiel, Claudia M; de Vries, Carlie J M

2014-11-01

The NR4A subfamily of nuclear receptors consists of three mammalian members: Nur77, Nurr1, and NOR-1. The NR4A receptors are involved in essential physiological processes such as adaptive and innate immune cell differentiation, metabolism and brain function. They act as transcription factors that directly modulate gene expression, but can also form trans-repressive complexes with other transcription factors. In contrast to steroid hormone nuclear receptors such as the estrogen receptor or the glucocorticoid receptor, no ligands have been described for the NR4A receptors. This lack of known ligands might be explained by the structure of the ligand-binding domain of NR4A receptors, which shows an active conformation and a ligand-binding pocket that is filled with bulky amino acid side-chains. Other mechanisms, such as transcriptional control, post-translational modifications and protein-protein interactions therefore seem to be more important in regulating the activity of the NR4A receptors. For Nur77, over 80 interacting proteins (the interactome) have been identified so far, and roughly half of these interactions has been studied in more detail. Although the NR4As show some overlap in interacting proteins, less information is available on the interactome of Nurr1 and NOR-1. Therefore, the present review will describe the current knowledge on the interactomes of all three NR4A nuclear receptors with emphasis on Nur77. Copyright © 2014 Elsevier B.V. All rights reserved.

Signatures of memory: brain coactivations during retrieval distinguish correct from incorrect recollection

Directory of Open Access Journals (Sweden)

Avi Mendelsohn

2010-04-01

Full Text Available Are specific distributed coactivations in the brain during memory retrieval a signature of retrieval outcome? Here we show that this is indeed the case. Widespread brain networks were reported to be involved in the retrieval of long-term episodic memories. Although functional coactivation among particular regions occurs during episodic memory retrieval, it is unknown to what extent it contributes to the accuracy and confidence of recollection. In this study we set out to explore this question. Participants saw a narrative documentary movie. A week later they underwent an fMRI scan during which they either accepted or rejected factual or fictitious verbal statements concerning the movie. Correct vs. incorrect responses to factual statements were more common and were provided with higher confidence than those made to fictitious statements. Whereas activity in the retrieval network correlated mostly with confidence, coactivations primarily correlated with memory accuracy. Specifically, coactivations of left medial temporal lobe regions with temporal and parietal cortices were greater during correct responses to factual statements, but did not differ between responses to fictitious statements. We propose that network coactivations play a role in recovering memory traces that are relevant to online retrieval cues, culminating in distinct retrieval outcomes.

The adipogenic acetyltransferase Tip60 targets activation function 1 of peroxisome proliferator-activated receptor gamma

DEFF Research Database (Denmark)

van Beekum, Olivier; Brenkman, Arjan B; Grøntved, Lars

2008-01-01

The transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) plays a key role in the regulation of lipid and glucose metabolism in adipocytes, by regulating their differentiation, maintenance, and function. The transcriptional activity of PPARgamma is dictated by the set...... in cells, and through use of chimeric proteins, we established that coactivation by Tip60 critically depends on the N-terminal activation function 1 of PPARgamma, a domain involved in isotype-specific gene expression and adipogenesis. Chromatin immunoprecipitation experiments showed that the endogenous Tip...... of proteins with which this nuclear receptor interacts under specific conditions. Here we identify the HIV-1 Tat-interacting protein 60 (Tip60) as a novel positive regulator of PPARgamma transcriptional activity. Using tandem mass spectrometry, we found that PPARgamma and the acetyltransferase Tip60 interact...

Decreased expression of thyroid receptor-associated protein 220 in temporal lobe tissue of patients with refractory epilepsy

International Nuclear Information System (INIS)

Li Jinmei; Wang Xuefeng; Xi Zhiqin; Gong Yun; Liu Fengying; Sun Jijun; Wu Yuan; Luan Guoming; Wang Yuping; Li Yunlin; Zhang Jianguo; Lu Yong; Li Hongwei

2006-01-01

Purpose: TRAP220 (thyroid hormone receptor-associated protein) functions as a coactivator for nuclear receptors and stimulates transcription by recruiting the TRAP mediator complex to hormone responsive promoter regions. Thus, TRAP220 enhances the function of thyroid/steroid hormone receptors such as thyroid hormone and oestrogen receptors. This study investigated the expression of TRAP220 mRNA and protein level in epileptic brains comparing with human control. Methods: We examined the expression of TRAP220 mRNA and protein levels in temporal lobes from patients with chronic pharmacoresistant epilepsy who have undergone surgery. Results: Expression of TRAP220 mRNA and protein was shown to be decreased significantly in the temporal cortex of the patients with epilepsy. Conclusions: Our work showed that a decrease in TRAP220 mRNA and protein levels may be involved in the pathophysiology of epilepsy and may be associated with impairment of the brain caused by frequent seizures

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.

Cross-talk between an activator of nuclear receptors-mediated transcription and the D1 dopamine receptor signaling pathway.

Science.gov (United States)

Schmidt, Azriel; Vogel, Robert; Rutledge, Su Jane; Opas, Evan E; Rodan, Gideon A; Friedman, Eitan

2005-03-01

Nuclear receptors are transcription factors that usually interact, in a ligand-dependent manner, with specific DNA sequences located within promoters of target genes. The nuclear receptors can also be controlled in a ligand-independent manner via the action of membrane receptors and cellular signaling pathways. 5-Tetradecyloxy-2-furancarboxylic acid (TOFA) was shown to stimulate transcription from the MMTV promoter via chimeric receptors that consist of the DNA binding domain of GR and the ligand binding regions of the PPARbeta or LXRbeta nuclear receptors (GR/PPARbeta and GR/LXRbeta). TOFA and hydroxycholesterols also modulate transcription from NF-kappaB- and AP-1-controlled reporter genes and induce neurite differentiation in PC12 cells. In CV-1 cells that express D(1) dopamine receptors, D(1) dopamine receptor stimulation was found to inhibit TOFA-stimulated transcription from the MMTV promoter that is under the control of chimeric GR/PPARbeta and GR/LXRbeta receptors. Treatment with the D(1) dopamine receptor antagonist, SCH23390, prevented dopamine-mediated suppression of transcription, and by itself increased transcription controlled by GR/LXRbeta. Furthermore, combined treatment of CV-1 cells with TOFA and SCH23390 increased transcription controlled by the GR/LXRbeta chimeric receptor synergistically. The significance of this in vitro synergy was demonstrated in vivo, by the observation that SCH23390 (but not haloperidol)-mediated catalepsy in rats was potentiated by TOFA, thus showing that an agent that mimics the in vitro activities of compounds that activate members of the LXR and PPAR receptor families can influence D1 dopamine receptor elicited responses.

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...... the world covering a wide spectrum from fundamental mechanistic studies to metabolism, clinical studies, and drug development. In this report, we summarize the recent and exciting findings presented by the speakers at the meeting....

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.

Enhancing the smoothness of joint motion induced by functional electrical stimulation using co-activation strategies

Directory of Open Access Journals (Sweden)

Ruppel Mirjana

2017-09-01

Full Text Available The motor precision of today’s neuroprosthetic devices that use artificial generation of limb motion using Functional Electrical Stimulation (FES is generally low. We investigate the adoption of natural co-activation strategies as present in antagonistic muscle pairs aiming to improve motor precision produced by FES. In a test in which artificial knee-joint movements were generated, we could improve the smoothness of FES-induced motion by 513% when applying co-activation during the phases in which torque production is switched between muscles – compared to no co-activation. We further demonstrated how the co-activation level influences the joint stiffness in a pendulum test.

Increased lower limb muscle coactivation reduces gait performance and increases metabolic cost in patients with hereditary spastic paraparesis.

Science.gov (United States)

Rinaldi, Martina; Ranavolo, Alberto; Conforto, Silvia; Martino, Giovanni; Draicchio, Francesco; Conte, Carmela; Varrecchia, Tiwana; Bini, Fabiano; Casali, Carlo; Pierelli, Francesco; Serrao, Mariano

2017-10-01

The aim of this study was to investigate the lower limb muscle coactivation and its relationship with muscles spasticity, gait performance, and metabolic cost in patients with hereditary spastic paraparesis. Kinematic, kinetic, electromyographic and energetic parameters of 23 patients and 23 controls were evaluated by computerized gait analysis system. We computed ankle and knee antagonist muscle coactivation indexes throughout the gait cycle and during the subphases of gait. Energy consumption and energy recovery were measured as well. In addition to the correlation analysis between coactivation indexes and clinical variables, correlations between coactivation indexes and time-distance, kinematic, kinetic, and energetic parameters were estimated. Increased coactivity indexes of both knee and ankle muscles throughout the gait cycle and during the subphases of gait were observed in patients compared with controls. Energetic parameters were significantly higher in patients than in controls. Both knee and ankle muscle coactivation indexes were positively correlated with knee and ankle spasticity (Ashworth score), respectively. Knee and ankle muscle coactivation indexes were both positively correlated with energy consumption and both negatively correlated with energy recovery. Positive correlations between the Ashworth score and lower limb muscle coactivation suggest that abnormal lower limb muscle coactivation in patients with hereditary spastic paraparesis reflects a primary deficit linked to lower limb spasticity. Furthermore, these abnormalities influence the energetic mechanisms during walking. Identifying excessive muscle coactivation may be helpful in individuating the rehabilitative treatments and designing specific orthosis to restrain spasticity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nontranscriptional regulation of SYK by the coactivator OCA-B is required at multiple stages of B cell development.

Science.gov (United States)

Siegel, Rachael; Kim, Unkyu; Patke, Alina; Yu, Xin; Ren, Xiaodi; Tarakhovsky, Alexander; Roeder, Robert G

2006-05-19

OCA-B was originally identified as a nuclear transcriptional coactivator that is essential for antigen-driven immune responses. The later identification of a membrane bound, myristoylated form of OCA-B suggested additional, unique functions in B cell signaling pathways. This study has shown that OCA-B also functions in the pre-B1-to-pre-B2 cell transition and, most surprisingly, that it directly interacts with SYK, a tyrosine kinase critical for pre-BCR and BCR signaling. This unprecedented type of interaction-a transcriptional coactivator with a signaling kinase-occurs in the cytoplasm and directly regulates SYK stability. This study indicates that OCA-B is required for pre-BCR and BCR signaling at multiple stages of B cell development through its nontranscriptional regulation of SYK. Combined with the deregulation of OCA-B target genes, this may help explain the multitude of defects observed in B cell development and immune responses of Oca-b-/- mice.

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.

Exclusive nuclear location of estrogen receptors in Squalus testis.

Science.gov (United States)

Callard, G V; Mak, P

1985-01-01

An estrogen (E)-binding molecule having both occupied and unoccupied sites is restricted to nuclear subfractions in the testis of the spiny dogfish (Squalus acanthias). We investigated the hypothesis that a species characterized by high body-fluid osmolarity (1010 mosM) has an estrogen receptor (ER) that binds to chromatin with high affinity and consequently resists redistribution during tissue processing. Although the steroid binding and sedimentation properties of the Squalus nuclear ER conformed to those of classical ER, its elution maximum from DNA-cellulose was unusually high (0.55 M NaCl). A tendency to adhere tightly to cell nuclei was reflected in the high salt concentration (0.43 M KCl) required to extract 50% of the receptors from the nuclear compartment during homogenization and in the stability of the nuclear ER population in the presence of high concentrations of a nonionic solute (urea) or increased buffer volume. Mixing and redistribution experiments showed that nuclear ER could be quantitatively and qualitatively measured in cytosolic extracts, ruling out the possibility that soluble receptors were being masked. Although Squalus oviduct ER was similar to that of testis, ER in the testis and liver of a related elasmobranch (Potamotrygon) that maintains osmotic equilibrium at 300 mosM more closely resembled mammalian ER in its elution maximum from DNA-cellulose (0.22 M NaCl) and cytosolic/nuclear ratios in low-salt buffers. We conclude that Squalus testis has a single ER pool located exclusively in the nuclear compartment. These observations support a revised concept of steroid action and further indicate that the chromatin affinity of the hormone-ER complex is an important factor in determining subfractional distribution during tissue processing. PMID:3856265

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.

Estrogen-related receptor α is essential for the expression of antioxidant protection genes and mitochondrial function

International Nuclear Information System (INIS)

Rangwala, Shamina M.; Li, Xiaoyan; Lindsley, Loren; Wang, Xiaomei; Shaughnessy, Stacey; Daniels, Thomas G.; Szustakowski, Joseph; Nirmala, N.R.; Wu, Zhidan; Stevenson, Susan C.

2007-01-01

Estrogen-related receptor α (ERRα) is an important mediator of mitochondrial biogenesis and function. To investigate the transcriptional network controlling these phenomena, we investigated mitochondrial gene expression in embryonic fibroblasts isolated from ERRα null mice. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) stimulated mitochondrial gene expression program in control cells, but not in the ERRα null cells. Interestingly, the induction of levels of mitochondrial oxidative stress protection genes in response to increased PGC-1α levels was dependent on ERRα. Furthermore, we found that the PGC-1α-mediated induction of estrogen-related receptor γ and nuclear respiratory factor 2 (NRF-2), was dependent on the presence of ERRα. Basal levels of NRF-2 were decreased in the absence of ERRα. The absence of ERRα resulted in a decrease in citrate synthase enzyme activity in response to PGC-1α overexpression. Our results indicate an essential role for ERRα as a key regulator of oxidative metabolism

Specific regulation of thermosensitive lipid droplet fusion by a nuclear hormone receptor pathway.

Science.gov (United States)

Li, Shiwei; Li, Qi; Kong, Yuanyuan; Wu, Shuang; Cui, Qingpo; Zhang, Mingming; Zhang, Shaobing O

2017-08-15

Nuclear receptors play important roles in regulating fat metabolism and energy production in humans. The regulatory functions and endogenous ligands of many nuclear receptors are still unidentified, however. Here, we report that CYP-37A1 (ortholog of human cytochrome P450 CYP4V2), EMB-8 (ortholog of human P450 oxidoreductase POR), and DAF-12 (homolog of human nuclear receptors VDR/LXR) constitute a hormone synthesis and nuclear receptor pathway in Caenorhabditis elegans This pathway specifically regulates the thermosensitive fusion of fat-storing lipid droplets. CYP-37A1, together with EMB-8, synthesizes a lipophilic hormone not identical to Δ7-dafachronic acid, which represses the fusion-promoting function of DAF-12. CYP-37A1 also negatively regulates thermotolerance and lifespan at high temperature in a DAF-12-dependent manner. Human CYP4V2 can substitute for CYP-37A1 in C. elegans This finding suggests the existence of a conserved CYP4V2-POR-nuclear receptor pathway that functions in converting multilocular lipid droplets to unilocular ones in human cells; misregulation of this pathway may lead to pathogenic fat storage.

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...

Autophagy activation, not peroxisome proliferator-activated receptor γ coactivator 1α, may mediate exercise-induced improvements in glucose handling during diet-induced obesity.

Science.gov (United States)

Rosa-Caldwell, Megan E; Brown, Jacob L; Lee, David E; Blackwell, Thomas A; Turner, Kyle W; Brown, Lemuel A; Perry, Richard A; Haynie, Wesley S; Washington, Tyrone A; Greene, Nicholas P

2017-09-01

What is the central question of this study? What are the individual and combined effects of muscle-specific peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) overexpression and physical activity during high-fat feeding on glucose and exercise tolerance? What is the main finding and its importance? Our main finding is that muscle-specific PGC-1α overexpression provides no protection against lipid-overload pathologies nor does it enhance exercise adaptations. Instead, physical activity, regardless of PGC-1α content, protects against high-fat diet-induced detriments. Activation of muscle autophagy was correlated with exercise protection, suggesting that autophagy might be a mediating factor for exercise-induced protection from lipid overload. The prevalence of glucose intolerance is alarmingly high. Efforts to promote mitochondrial biogenesis through peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) to mitigate glucose intolerance have been controversial. However, physical activity remains a primary means to alleviate the condition. The aim of this study was to determine the combined effects of muscle-specific overexpression of PGC-1α and physical activity on glucose handling during diet-induced obesity. Wild-type (WT, ∼20) and PGC-1α muscle transgenic (MCK-PGC-1α, ∼20) mice were given a Western diet (WD) at 8 weeks age and allowed to consume food ab libitum throughout the study. At 12 weeks of age, all animals were divided into sedentary (SED) or voluntary wheel running (VWR) interventions. At 7, 11 and 15 weeks of age, animals underwent glucose tolerance tests (GTT) and graded exercise tests (GXT). At 16 weeks of age, tissues were collected. At 11 weeks, the MCK-PGC-1α animals had 50% greater glucose tolerance integrated area under the curve compared with WT. However, at 15 weeks, SED animals also had greater GTT integrated area under the curve compared with VWR, regardless of genotype; furthermore, SED

Circadian Rhythm of Hepatic Cytosolic and Nuclear Estrogen and Androgen Receptors

Science.gov (United States)

FRANCAVILLA, ANTONIO; EAGON, PATRICIA K.; DiLEO, ALFREDO; VAN THIEL, DAVID H.; PANELLA, CARMINE; POLIMENO, LORENZO; AMORUSO, CINZIA; INGROSSO, MARCELLO; AQUILINO, A. MARIA; STARZL, THOMAS E.

2010-01-01

Mammalian liver is a sex steroid-responsive tissue. The effects of these hormones presumably are mediated by hepatic estrogen receptors (ER) and androgen receptors (AR). Serum levels of sex hormones display circadian rhythms. Further, estrogens and androgens are commonly administered; administration of these agents is associated frequently with liver disease. Therefore, we investigated whether the cytosolic and nuclear sex steroid receptors also display a similar circadian rhythm, and whether variations occurred in the distribution of receptors between cytosolic and nuclear compartments. Animals were killed every 4 h from midnight till the following midnight; cytosolic and nuclear levels of both ER and AR were measured. Cytosolic ER reached a maximum level at 4 AM, and a minimum at 8 PM and midnight of both days. Nuclear ER was highest at 8 AM and lowest at 4 PM and 8 PM, a pattern which parallels variations in serum estradiol levels. Cytosolic AR was highest at 8 PM and lowest at midnight and 4 AM. Nuclear AR was highest at 4 AM and lowest at 4 PM and 8 PM. The highest level of nuclear AR does not correspond to the maximum serum testosterone level, which occurred at 4 PM. The total hepatic content of both ER and AR was not constant over the 24-h period, but varied considerably with time of day. These studies suggest that both ER and AR show a distinct circadian rhythm in subcellular compartmentalization, and that total hepatic content of ER and AR varies significantly during a 24-h period. PMID:3710067

Two Differential Binding Mechanisms of FG-Nucleoporins and Nuclear Transport Receptors

Directory of Open Access Journals (Sweden)

Piau Siong Tan

2018-03-01

Full Text Available Summary: Phenylalanine-glycine-rich nucleoporins (FG-Nups are intrinsically disordered proteins, constituting the selective barrier of the nuclear pore complex (NPC. Previous studies showed that nuclear transport receptors (NTRs were found to interact with FG-Nups by forming an “archetypal-fuzzy” complex through the rapid formation and breakage of interactions with many individual FG motifs. Here, we use single-molecule studies combined with atomistic simulations to show that, in sharp contrast, FG-Nup214 undergoes a coupled reconfiguration-binding mechanism when interacting with the export receptor CRM1. Association and dissociation rate constants are more than an order of magnitude lower than in the archetypal-fuzzy complex between FG-Nup153 and NTRs. Unexpectedly, this behavior appears not to be encoded selectively into CRM1 but rather into the FG-Nup214 sequence. The same distinct binding mechanisms are unperturbed in O-linked β-N-acetylglucosamine-modified FG-Nups. Our results have implications for differential roles of distinctly spatially distributed FG-Nup⋅NTR interactions in the cell. : Archetypal-fuzzy complexes found in most FG-Nucleoporin⋅nuclear transport receptor complexes allow fast yet specific nuclear transport. Tan et al. show that FG-Nup214, located at the periphery of the nuclear pore complex, binds to CRM1⋅RanGTP via a coupled reconfiguration-binding mechanism, which can enable different functionalities e.g., cargo release. Keywords: intrinsically disordered protein, glycosylation, FG-Nup, nuclear transport receptors, binding mechanism, single-molecule FRET, molecular dynamics simulations

Expression of glucocorticoid and progesterone nuclear receptor genes in archival breast cancer tissue

International Nuclear Information System (INIS)

Smith, Robert A; Lea, Rod A; Curran, Joanne E; Weinstein, Stephen R; Griffiths, Lyn R

2003-01-01

Previous studies in our laboratory have shown associations of specific nuclear receptor gene variants with sporadic breast cancer. In order to investigate these findings further, we conducted the present study to determine whether expression levels of the progesterone and glucocorticoid nuclear receptor genes vary in different breast cancer grades. RNA was extracted from paraffin-embedded archival breast tumour tissue and converted into cDNA. Sample cDNA underwent PCR using labelled primers to enable quantitation of mRNA expression. Expression data were normalized against the 18S ribosomal gene multiplex and analyzed using analysis of variance. Analysis of variance indicated a variable level of expression of both genes with regard to breast cancer grade (P = 0.00033 for glucocorticoid receptor and P = 0.023 for progesterone receptor). Statistical analysis indicated that expression of the progesterone nuclear receptor is elevated in late grade breast cancer tissue

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.

Dietary modification of metabolic pathways via nuclear hormone receptors.

Science.gov (United States)

Caiozzi, Gianella; Wong, Brian S; Ricketts, Marie-Louise

2012-10-01

Nuclear hormone receptors (NHRs), as ligand-dependent transcription factors, have emerged as important mediators in the control of whole body metabolism. Because of the promiscuous nature of several members of this superfamily that have been found to bind ligand with lower affinity than the classical steroid NHRs, they consequently display a broader ligand selectivity. This promiscuous nature has facilitated various bioactive dietary components being able to act as agonist ligands for certain members of the NHR superfamily. By binding to these NHRs, bioactive dietary components are able to mediate changes in various metabolic pathways, including, glucose, cholesterol and triglyceride homeostasis among others. This review will provide a general overview of the nuclear hormone receptors that have been shown to be activated by dietary components. The physiological consequences of such receptor activation by these dietary components will then be discussed in more detail. Copyright © 2012 John Wiley & Sons, Ltd.

Task vs. rest-different network configurations between the coactivation and the resting-state brain networks.

Science.gov (United States)

Di, Xin; Gohel, Suril; Kim, Eun H; Biswal, Bharat B

2013-01-01

There is a growing interest in studies of human brain networks using resting-state functional magnetic resonance imaging (fMRI). However, it is unclear whether and how brain networks measured during the resting-state exhibit comparable properties to brain networks during task performance. In the present study, we investigated meta-analytic coactivation patterns among brain regions based upon published neuroimaging studies, and compared the coactivation network configurations with those in the resting-state network. The strength of resting-state functional connectivity between two regions were strongly correlated with the coactivation strength. However, the coactivation network showed greater global efficiency, smaller mean clustering coefficient, and lower modularity compared with the resting-state network, which suggest a more efficient global information transmission and between system integrations during task performing. Hub shifts were also observed within the thalamus and the left inferior temporal cortex. The thalamus and the left inferior temporal cortex exhibited higher and lower degrees, respectively in the coactivation network compared with the resting-state network. These results shed light regarding the reconfiguration of the brain networks between task and resting-state conditions, and highlight the role of the thalamus in change of network configurations in task vs. rest.

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.

Functional interaction between nonreceptor tyrosine kinase c-Abl and SR-Rich protein RBM39

International Nuclear Information System (INIS)

Mai, Sanyue; Qu, Xiuhua; Li, Ping; Ma, Qingjun; Liu, Xuan; Cao, Cheng

2016-01-01

RBM39, also known as splicing factor HCC1.4, acts as a transcriptional coactivator for the steroid nuclear receptors JUN/AP-1, ESR1/ER-α and ESR2/ER-β. RBM39 is involved in the regulation of the transcriptional responses of these steroid nuclear receptors and promotes transcriptional initiation. In this paper, we report that RBM39 interacts with the nonreceptor tyrosine kinase c-Abl. Both the Src homology (SH) 2 and SH3 domains of c-Abl interact with RBM39. The major tyrosine phosphorylation sites on RBM39 that are phosphorylated by c-Abl are Y95 and Y99, as demonstrated by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) and mutational analysis. c-Abl was shown boost the transcriptional coactivation activity of RBM39 for ERα and PRβ in a tyrosine kinase-dependent manner. The results suggest that mammalian c-Abl plays an important role in steroid hormone receptor-mediated transcription by regulating RBM39. - Highlights: • c-Abl interacts with RBM39. • RBM39 is phosphorylated by c-Abl. • c-Abl regulates transcriptional coactivation activity of RBM39 on the ERα and PRβ.

Functional interaction between nonreceptor tyrosine kinase c-Abl and SR-Rich protein RBM39

Energy Technology Data Exchange (ETDEWEB)

Mai, Sanyue [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China); Qu, Xiuhua [General Navy Hospital of PLA, 6 Fucheng Rd, Haidian District, Beijing 100037 (China); Li, Ping; Ma, Qingjun [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China); Liu, Xuan, E-mail: liux931932@163.com [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China); Cao, Cheng, E-mail: cao_c@sohu.com [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China)

2016-04-22

RBM39, also known as splicing factor HCC1.4, acts as a transcriptional coactivator for the steroid nuclear receptors JUN/AP-1, ESR1/ER-α and ESR2/ER-β. RBM39 is involved in the regulation of the transcriptional responses of these steroid nuclear receptors and promotes transcriptional initiation. In this paper, we report that RBM39 interacts with the nonreceptor tyrosine kinase c-Abl. Both the Src homology (SH) 2 and SH3 domains of c-Abl interact with RBM39. The major tyrosine phosphorylation sites on RBM39 that are phosphorylated by c-Abl are Y95 and Y99, as demonstrated by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) and mutational analysis. c-Abl was shown boost the transcriptional coactivation activity of RBM39 for ERα and PRβ in a tyrosine kinase-dependent manner. The results suggest that mammalian c-Abl plays an important role in steroid hormone receptor-mediated transcription by regulating RBM39. - Highlights: • c-Abl interacts with RBM39. • RBM39 is phosphorylated by c-Abl. • c-Abl regulates transcriptional coactivation activity of RBM39 on the ERα and PRβ.

Transcriptional co-activator PGC-1 alpha drives the formation of slow-twitch muscle fibres.

Science.gov (United States)

Lin, Jiandie; Wu, Hai; Tarr, Paul T; Zhang, Chen-Yu; Wu, Zhidan; Boss, Olivier; Michael, Laura F; Puigserver, Pere; Isotani, Eiji; Olson, Eric N; Lowell, Bradford B; Bassel-Duby, Rhonda; Spiegelman, Bruce M

2002-08-15

The biochemical basis for the regulation of fibre-type determination in skeletal muscle is not well understood. In addition to the expression of particular myofibrillar proteins, type I (slow-twitch) fibres are much higher in mitochondrial content and are more dependent on oxidative metabolism than type II (fast-twitch) fibres. We have previously identified a transcriptional co-activator, peroxisome-proliferator-activated receptor-gamma co-activator-1 (PGC-1 alpha), which is expressed in several tissues including brown fat and skeletal muscle, and that activates mitochondrial biogenesis and oxidative metabolism. We show here that PGC-1 alpha is expressed preferentially in muscle enriched in type I fibres. When PGC-1 alpha is expressed at physiological levels in transgenic mice driven by a muscle creatine kinase (MCK) promoter, a fibre type conversion is observed: muscles normally rich in type II fibres are redder and activate genes of mitochondrial oxidative metabolism. Notably, putative type II muscles from PGC-1 alpha transgenic mice also express proteins characteristic of type I fibres, such as troponin I (slow) and myoglobin, and show a much greater resistance to electrically stimulated fatigue. Using fibre-type-specific promoters, we show in cultured muscle cells that PGC-1 alpha activates transcription in cooperation with Mef2 proteins and serves as a target for calcineurin signalling, which has been implicated in slow fibre gene expression. These data indicate that PGC-1 alpha is a principal factor regulating muscle fibre type determination.

Daphnia HR96 is a promiscuous xenobiotic and endobiotic nuclear receptor

International Nuclear Information System (INIS)

Karimullina, Elina; Li Yangchun; Ginjupalli, Gautam K.; Baldwin, William S.

2012-01-01

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.

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.

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

International Nuclear Information System (INIS)

Whelan, Jarrett T.; Wang, Lei; Chen, Jianming; Metts, Meagan E.; Nasser, Taj A.; McGoldrick, Liam J.; Bridges, Lance C.

2014-01-01

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) 2 D 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

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.

NR4A nuclear receptors are orphans but not lonesome

NARCIS (Netherlands)

Kurakula, Kondababu; Koenis, Duco S.; van Tiel, Claudia M.; de Vries, Carlie J. M.

2014-01-01

The NR4A subfamily of nuclear receptors consists of three mammalian members: Nur77, Nurr1, and NOR-1. The NR4A receptors are involved in essential physiological processes such as adaptive and innate immune cell differentiation, metabolism and brain function. They act as transcription factors that

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.

Microsomal receptor for steroid hormones: functional implications for nuclear activity.

Science.gov (United States)

Muldoon, T G; Watson, G H; Evans, A C; Steinsapir, J

1988-01-01

microsomal binding sites extracted. These observations suggest three possible roles for the microsomal receptor-like proteins: (a) modulation of estrogen access to nuclear binding sites; (b) formation of functional complexes which diffuse to other extranuclear sites to alter non-genomic cellular processes; (c) regulation of nuclear concentration of estrogen-receptor complexes by virtue of producing microsomal acceptor sites for uptake of free or loosely associated nuclear complexes, previously thought to exist in the cytoplasm.

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.

Nuclear hormone receptors in parasitic helminths

OpenAIRE

Wu, Wenjie; LoVerde, Philip T

2010-01-01

Nuclear receptors (NRs) belong to a large protein superfamily that are important transcriptional modulators in metazoans. Parasitic helminths include parasitic worms from the Lophotrochozoa (Platyhelminths) and Ecdysozoa (Nematoda). NRs in parasitic helminths diverged into two different evolutionary lineages. NRs in parasitic Platyhelminths have orthologues in Deuterostomes, in arthropods or both with a feature of extensive gene loss and gene duplication within different gene groups. NRs in p...

Task vs. rest—different network configurations between the coactivation and the resting-state brain networks

Science.gov (United States)

Di, Xin; Gohel, Suril; Kim, Eun H.; Biswal, Bharat B.

2013-01-01

There is a growing interest in studies of human brain networks using resting-state functional magnetic resonance imaging (fMRI). However, it is unclear whether and how brain networks measured during the resting-state exhibit comparable properties to brain networks during task performance. In the present study, we investigated meta-analytic coactivation patterns among brain regions based upon published neuroimaging studies, and compared the coactivation network configurations with those in the resting-state network. The strength of resting-state functional connectivity between two regions were strongly correlated with the coactivation strength. However, the coactivation network showed greater global efficiency, smaller mean clustering coefficient, and lower modularity compared with the resting-state network, which suggest a more efficient global information transmission and between system integrations during task performing. Hub shifts were also observed within the thalamus and the left inferior temporal cortex. The thalamus and the left inferior temporal cortex exhibited higher and lower degrees, respectively in the coactivation network compared with the resting-state network. These results shed light regarding the reconfiguration of the brain networks between task and resting-state conditions, and highlight the role of the thalamus in change of network configurations in task vs. rest. PMID:24062654

Genome-wide identification of nuclear receptor (NR) superfamily genes in the copepod Tigriopus japonicus.

Science.gov (United States)

Hwang, Dae-Sik; Lee, Bo-Young; Kim, Hui-Su; Lee, Min Chul; Kyung, Do-Hyun; Om, Ae-Son; Rhee, Jae-Sung; Lee, Jae-Seong

2014-11-18

Nuclear receptors (NRs) are a large superfamily of proteins defined by a DNA-binding domain (DBD) and a ligand-binding domain (LBD). They function as transcriptional regulators to control expression of genes involved in development, homeostasis, and metabolism. The number of NRs differs from species to species, because of gene duplications and/or lineage-specific gene losses during metazoan evolution. Many NRs in arthropods interact with the ecdysteroid hormone and are involved in ecdysone-mediated signaling in arthropods. The nuclear receptor superfamily complement has been reported in several arthropods, including crustaceans, but not in copepods. We identified the entire NR repertoire of the copepod Tigriopus japonicus, which is an important marine model species for ecotoxicology and environmental genomics. Using whole genome and transcriptome sequences, we identified a total of 31 nuclear receptors in the genome of T. japonicus. Nomenclature of the nuclear receptors was determined based on the sequence similarities of the DNA-binding domain (DBD) and ligand-binding domain (LBD). The 7 subfamilies of NRs separate into five major clades (subfamilies NR1, NR2, NR3, NR4, and NR5/6). Although the repertoire of NR members in, T. japonicus was similar to that reported for other arthropods, there was an expansion of the NR1 subfamily in Tigriopus japonicus. The twelve unique nuclear receptors identified in T. japonicus are members of NR1L. This expansion may be a unique lineage-specific feature of crustaceans. Interestingly, E78 and HR83, which are present in other arthropods, were absent from the genomes of T. japonicus and two congeneric copepod species (T. japonicus and Tigriopus californicus), suggesting copepod lineage-specific gene loss. We identified all NR receptors present in the copepod, T. japonicus. Knowledge of the copepod nuclear receptor repertoire will contribute to a better understanding of copepod- and crustacean-specific NR evolution.

Genome inventory and analysis of nuclear hormone receptors in ...

Indian Academy of Sciences (India)

Prakash

2006-12-20

Dec 20, 2006 ... progestins, as well as lipids, cholesterol metabolites, and. Genome ... Gene structure analysis shows strong conservation of exon structures among orthologoues. ..... earlier subfamily classification of NRs (Nuclear Receptors.

Nuclear Import and Export of the Thyroid Hormone Receptor.

Science.gov (United States)

Zhang, Jibo; Roggero, Vincent R; Allison, Lizabeth A

2018-01-01

The thyroid hormone receptors, TRα1 and TRβ1, are members of the nuclear receptor superfamily that forms one of the most abundant classes of transcription factors in multicellular organisms. Although primarily localized to the nucleus, TRα1 and TRβ1 shuttle rapidly between the nucleus and cytoplasm. The fine balance between nuclear import and export of TRs has emerged as a critical control point for modulating thyroid hormone-responsive gene expression. Mutagenesis studies have defined two nuclear localization signal (NLS) motifs that direct nuclear import of TRα1: NLS-1 in the hinge domain and NLS-2 in the N-terminal A/B domain. Three nuclear export signal (NES) motifs reside in the ligand-binding domain. A combined approach of shRNA-mediated knockdown and coimmunoprecipitation assays revealed that nuclear entry of TRα1 is facilitated by importin 7, likely through interactions with NLS-2, and importin β1 and the adapter importin α1 interacting with both NLS-1 and NLS-2. Interestingly, TRβ1 lacks NLS-2 and nuclear import depends solely on the importin α1/β1 heterodimer. Heterokaryon and fluorescence recovery after photobleaching shuttling assays identified multiple exportins that play a role in nuclear export of TRα1, including CRM1 (exportin 1), and exportins 4, 5, and 7. Even single amino acid changes in TRs dramatically alter their intracellular distribution patterns. We conclude that mutations within NLS and NES motifs affect nuclear shuttling activity, and propose that TR mislocalization contributes to the development of some types of cancer and Resistance to Thyroid Hormone syndrome. © 2018 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

Kolodkin, Alexey N; Bruggeman, Frank J; Plant, Nick; Moné, 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 increasing complexity, calculations show how these features correspond to potentially important design principles, e.g.: (i) cytosolic ‘nuclear' receptor may shuttle signal molecules to the nucleus, (ii) the active export of NRs may ensure that there is sufficient receptor protein to capture ligand at the cytoplasmic membrane, (iii) a three conveyor belts design dissipating GTP-free energy, greatly aids response, (iv) the active export of importins may prevent sequestration of NRs by importins in the nucleus and (v) the unspecific nature of the nuclear pore may ensure signal-flux robustness. In addition, the models developed are suitable for implementation in specific cases of NR-mediated signaling, to predict individual receptor functions and differential sensitivity toward physiological and pharmacological ligands. PMID:21179018

NMDA receptor dependent PGC-1alpha up-regulation protects the cortical neuron against oxygen-glucose deprivation/reperfusion injury.

Science.gov (United States)

Luo, Yun; Zhu, Wenjing; Jia, Jia; Zhang, Chenyu; Xu, Yun

2009-09-01

The peroxisome proliferator activated receptor coactivator 1 alpha (PGC-1alpha) is a nuclear transcriptional coactivator that is widely expressed in the brain areas. Over-expression of PGC-1alpha can protect neuronal cells from oxidant-induced injury. The purpose of the current study is to investigate the role of PGC-1alpha in the oxygen (anoxia) deprivation (OGD) neurons. The PGC-1alpha mRNA and protein level between control and OGD neurons were examined by real-time PCR and Western blot. More PGC-1alpha expression was found in the OGD neurons compared with the normal group. Over-expression of PGC-1alpha suppressed cell apoptosis while inhibition of the PGC-1alpha expression induced cell apoptosis in OGD neurons. Furthermore, increase of PGC-1alpha resulted in activation of N-methyl-D-aspartate (NMDA) receptor, p38, and ERK mitogen-activated protein kinase (MAPK) pathway. The blocking of the NMDA receptor by its antagonists MK-801 reduced PGC-1alpha mRNA expression in OGD neurons, while NMDA itself can directly induce the expression of PGC-1alpha in neuronal cells. At the same time, PD98059 (ERK MAPK inhibitor) and SB203580 (P38 MAPK inhibitor) also prevented the up-regulation of PGC-1alpha in OGD neurons and MK801 can inhibit the expression of P38 and ERK MAPK. These data suggested that the expression of PGC-1alpha was up-regulated in OGD mice cortical neurons, which protected the neurons against OGD injury. Moreover, this effect was correlated to the NMDA receptor and the ERK and P38 MAPK pathway. The protective effect of PGC-1alpha on OGD cortical neurons may be useful for stroke therapy.

Phase-dependence of elbow muscle coactivation in front crawl swimming.

Science.gov (United States)

Lauer, Jessy; Figueiredo, Pedro; Vilas-Boas, João Paulo; Fernandes, Ricardo J; Rouard, Annie Hélène

2013-08-01

Propulsion in swimming is achieved by complex sculling movements with elbow quasi-fixed on the antero-posterior axis to transmit forces from the hand and the forearm to the body. The purpose of this study was to investigate how elbow muscle coactivation was influenced by the front crawl stroke phases. Ten international level male swimmers performed a 200-m front crawl race-pace bout. Sagittal views were digitized frame by frame to determine the stroke phases (aquatic elbow flexion and extension, aerial elbow flexion and extension). Surface electromyograms (EMG) of the right biceps brachii and triceps brachii were recorded and processed using the integrated EMG to calculate a coactivation index (CI) for each phase. A significant effect of the phases on the CI was revealed with highest levels of coactivation during the aquatic elbow flexion and the aerial elbow extension. Swimmers stabilize the elbow joint to overcome drag during the aquatic phase, and act as a brake at the end of the recovery to replace the arm for the next stroke. The CI can provide insight into the magnitude of mechanical constraints supported by a given joint, in particular during a complex movement. Copyright © 2013 Elsevier Ltd. All rights reserved.

SMRT repression of nuclear receptors controls the adipogenic set point and metabolic homeostasis

NARCIS (Netherlands)

Nofsinger, Russell R.; Li, Pingping; Hong, Suk-Hyun; Jonker, Johan W.; Barish, Grant D.; Ying, Hao; Cheng, Sheue-Yann; LeBlanc, Mathias; Xu, Wei; Pei, Liming; Kang, Yeon-Joo; Nelson, Michael; Downes, Michael; Yu, Ruth T.; Olefsky, Jerrold M.; Lee, Chih-Hao; Evans, Ronald M.

2008-01-01

The nuclear receptor corepressor, silencing mediator of retinoid and thyroid hormone receptors (SMRT), is recruited by a plethora of transcription factors to mediate lineage and signal-dependent transcriptional repression. We generated a knockin mutation in the receptor interaction domain (RID) of

Thermoluminescent coactivated rare earth oxyhalide phosphors and x-ray image converters utilizing said phosphors

International Nuclear Information System (INIS)

Rabatin, J.G.

1984-01-01

Oxyhalides of lanthanum, gadolinium and lutetium coactivated with a first activator selected from bismuth and samarium to provide the color of light emission and a second coactivator (e.g. terbium or praseodymium) which increases the amount of stored energy in a stored radiographic latent image are found to be superior in their conversion efficiency of x-rays to visible light. (author)

Thyroid hormone and retinoic acid nuclear receptors: specific ligand-activated transcription factors

International Nuclear Information System (INIS)

Brtko, J.

1998-01-01

Transcriptional regulation by both the thyroid hormone and the vitamin A-derived 'retinoid hormones' is a critical component in controlling many aspects of higher vertebrate development and metabolism. Their functions are mediated by nuclear receptors, which comprise a large super-family of ligand-inducible transcription factors. Both the thyroid hormone and the retinoids are involved in a complex arrangement of physiological and development responses in many tissues of higher vertebrates. The functions of 3,5,3'-triiodothyronine (T 3 ), the thyromimetically active metabolite of thyroxine as well as all-trans retinoic acid, the biologically active vitamin A metabolite are mediated by nuclear receptor proteins that are members of the steroid/thyroid/retinoid hormone receptor family. The functions of all members of the receptor super family are discussed. (authors)

Panning for SNuRMs: using cofactor profiling for the rational discovery of selective nuclear receptor modulators.

Science.gov (United States)

Kremoser, Claus; Albers, Michael; Burris, Thomas P; Deuschle, Ulrich; Koegl, Manfred

2007-10-01

Drugs that target nuclear receptors are clinically, as well as commercially, successful. Their widespread use, however, is limited by an inherent propensity of nuclear receptors to trigger beneficial, as well as adverse, pharmacological effects upon drug activation. Hence, selective drugs that display reduced adverse effects, such as the selective estrogen receptor modulator (SERM) Raloxifene, have been developed by guidance through classical cell culture assays and animal trials. Full agonist and selective modulator nuclear receptor drugs, in general, differ by their ability to recruit certain cofactors to the receptor protein. Hence, systematic cofactor profiling is advancing into an approach for the rationally guided identification of selective NR modulators (SNuRMs) with improved therapeutic ratio.

Helix 11 Dynamics is Critical for Constitutive Androstane Receptor Activity

OpenAIRE

Wright, Edward; Busby, Scott A.; Wisecarver, Sarah; Vincent, Jeremy; Griffin, Patrick R.; Fernandez, Elias J.

2011-01-01

The constitutive androstane receptor (CAR) transactivation can occur in the absence of exogenous ligand and this activity is enhanced by agonists TCPOBOP and meclizine. We use biophysical and cell-based assays to show that increased activity of CAR(TCPOBOP) relative to CAR(meclizine) corresponds to a higher affinity of CAR(TCPOBOP) for the steroid receptor coactivator-1. Additionally, steady-state fluorescence spectra suggest conformational differences between CAR(TCPOBOP):RXR and CAR(meclizi...

Examination of VDR/RXR/DRIP205 Interaction, Intranuclear Localization, and DNA Binding in Ras-Transformed Keratinocytes and Its Implication for Designing Optimal Vitamin D Therapy in Cancer.

Science.gov (United States)

Jusu, Sylvester; Presley, John F; Williams, Chris; Das, Sanjoy Kumar; Jean-Claude, Bertrand; Kremer, Richard

2018-03-01

Retinoid X receptor (RXR) occupies a central position within the nuclear receptor superfamily, serving as an obligatory partner to numerous other nuclear receptors, including vitamin D receptor (VDR). In the current study, we examined whether phosphorylation of RXRα at serine 260 affects VDR/RXR and VDR interacting protein (DRIP) 205 coactivator recruitment, interactions, and binding of the VDR/human RXRα (hRXRα)/DRIP205 complex to chromatin. Serine 260 is a critical amino acid on the hRXRα that is located in close spatial proximity to regions of coactivator and corepressor interactions. Using fluorescence resonance energy transfer and immunofluorescence studies, we showed that the physical interaction between hRXRα and DRIP205 coactivator was impaired in human keratinocytes with the ras oncogene (HPK1Aras) or transfected with the wild-type hRXRα. Furthermore, the nuclear colocalization of VDR/DRIP205, hRXRα/DRIP205, and VDR/hRXRα/DRIP205 complex binding to chromatin is impaired in the HPK1Aras cells when compared with the normal human keratinocytes (HPK1A cells). However, transfection with the nonphosphorylatable hRXRα (S260A) mutant or treatment with the mitogen-activated protein kinase (MAPK) inhibitor UO126 rescued their nuclear localization, interaction, and binding of the complex to chromatin in the HPK1Aras cells. In summary, we have demonstrated, using highly specific intracellular tagging methods in live and fixed cells, important alterations of the vitamin D signaling system in cancer cells in which the ras-raf-MAPK system is activated, suggesting that specific inhibition of this commonly activated pathway could be targeted therapeutically to enhance vitamin D efficacy. Copyright © 2018 Endocrine Society.

XX ovarian dysgenesis is caused by a PSMC3IP/HOP2 mutation that abolishes coactivation of estrogen-driven transcription.

Science.gov (United States)

Zangen, David; Kaufman, Yotam; Zeligson, Sharon; Perlberg, Shira; Fridman, Hila; Kanaan, Moein; Abdulhadi-Atwan, Maha; Abu Libdeh, Abdulsalam; Gussow, Ayal; Kisslov, Irit; Carmel, Liran; Renbaum, Paul; Levy-Lahad, Ephrat

2011-10-07

XX female gonadal dysgenesis (XX-GD) is a rare, genetically heterogeneous disorder characterized by lack of spontaneous pubertal development, primary amenorrhea, uterine hypoplasia, and hypergonadotropic hypogonadism as a result of streak gonads. Most cases are unexplained but thought to be autosomal recessive. We elucidated the genetic basis of XX-GD in a highly consanguineous Palestinian family by using homozygosity mapping and candidate-gene and whole-exome sequencing. Affected females were homozygous for a 3 bp deletion (NM_016556.2, c.600_602del) in the PSMC3IP gene, leading to deletion of a glutamic acid residue (p.Glu201del) in the highly conserved C-terminal acidic domain. Proteasome 26S subunit, ATPase, 3-Interacting Protein (PSMC3IP)/Tat Binding Protein Interacting Protein (TBPIP) is a nuclear, tissue-specific protein with multiple functions. It is critical for meiotic recombination as indicated by the known role of its yeast ortholog, Hop2. Through the C terminus (not present in yeast), PSMC3IP also coactivates ligand-driven transcription mediated by estrogen, androgen, glucocorticoid, progesterone, and thyroid nuclear receptors. In cell lines, the p.Glu201del mutation abolished PSMC3IP activation of estrogen-driven transcription. Impaired estrogenic signaling can lead to ovarian dysgenesis both by affecting the size of the follicular pool created during fetal development and by failing to counteract follicular atresia during puberty. PSMC3IP joins previous genes known to be mutated in XX-GD, the FSH receptor, and BMP15, highlighting the importance of hormonal signaling in ovarian development and maintenance and suggesting a common pathway perturbed in isolated XX-GD. By analogy to other XX-GD genes, PSMC3IP is also a candidate gene for premature ovarian failure, and its role in folliculogenesis should be further investigated. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Activation of Akt is essential for the propagation of mitochondrial respiratory stress signaling and activation of the transcriptional coactivator heterogeneous ribonucleoprotein A2.

Science.gov (United States)

Guha, Manti; Fang, Ji-Kang; Monks, Robert; Birnbaum, Morris J; Avadhani, Narayan G

2010-10-15

Mitochondrial respiratory stress (also called mitochondrial retrograde signaling) activates a Ca(2+)/calcineurin-mediated signal that culminates in transcription activation/repression of a large number of nuclear genes. This signal is propagated through activation of the regulatory proteins NFκB c-Rel/p50, C/EBPδ, CREB, and NFAT. Additionally, the heterogeneous ribonucleoprotein A2 (hnRNPA2) functions as a coactivator in up-regulating the transcription of Cathepsin L, RyR1, and Glut-4, the target genes of stress signaling. Activation of IGF1R, which causes a metabolic switch to glycolysis, cell invasiveness, and resistance to apoptosis, is a phenotypic hallmark of C2C12 myoblasts subjected to mitochondrial stress. In this study, we report that mitochondrial stress leads to increased expression, activation, and nuclear localization of Akt1. Mitochondrial respiratory stress also activates Akt1-gene expression, which involves hnRNPA2 as a coactivator, indicating a complex interdependency of these two factors. Using Akt1(-/-) mouse embryonic fibroblasts and Akt1 mRNA-silenced C2C12 cells, we show that Akt1-mediated phosphorylation is crucial for the activation and recruitment of hnRNPA2 to the enhanceosome complex. Akt1 mRNA silencing in mtDNA-depleted cells resulted in reversal of the invasive phenotype, accompanied by sensitivity to apoptotic stimuli. These results show that Akt1 is an important regulator of the nuclear transcriptional response to mitochondrial stress.

Human pregnane X receptor is activated by dibenzazepine carbamate-based inhibitors of constitutive androstane receptor.

Science.gov (United States)

Jeske, Judith; Windshügel, Björn; Thasler, Wolfgang E; Schwab, Matthias; Burk, Oliver

2017-06-01

Unintentional activation of xenosensing nuclear receptors pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR) by clinical drug use is known to produce severe side effects in patients, which may be overcome by co-administering antagonists. However, especially antagonizing CAR is hampered by the lack of specific inhibitors, which do not activate PXR. Recently, compounds based on a dibenzazepine carbamate scaffold were identified as potent CAR inhibitors. However, their potential to activate PXR was not thoroughly investigated, even if the lead compound was named "CAR inhibitor not PXR activator 1" (CINPA1). Thus, we performed a comprehensive analysis of the interaction of CINPA1 and four analogs with PXR. Cellular assays were used to investigate intra- and intermolecular interactions and transactivation activity of PXR as a function of the compounds. Modulation of PXR target gene expression was analyzed in primary human hepatocytes. Ligand binding to PXR was investigated by molecular docking and limited proteolytic digestion. We show here that CINPA1 induced the assembly of the PXR ligand-binding domain, released co-repressors from and recruited co-activators to the receptor. CINPA1 and its analogs induced the PXR-dependent activation of a CYP3A4 reporter gene and CINPA1 induced the expression of endogenous cytochrome P450 genes in primary hepatocytes, while not consistently inhibiting CAR-mediated induction. Molecular docking revealed favorable binding of CINPA1 and analogs to the PXR ligand-binding pocket, which was confirmed in vitro. Altogether, our data provide consistent evidence that compounds with a dibenzazepine carbamate scaffold, such as CINPA1 and its four analogs, bind to and activate PXR.

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

Autoimmune regulator is acetylated by transcription coactivator CBP/p300

Energy Technology Data Exchange (ETDEWEB)

Saare, Mario, E-mail: mario.saare@ut.ee [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu (Estonia); Rebane, Ana [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu (Estonia); SIAF, Swiss Institute of Allergy and Asthma Research, University of Zuerich, Davos (Switzerland); Rajashekar, Balaji; Vilo, Jaak [BIIT, Bioinformatics, Algorithmics and Data Mining group, Institute of Computer Science, University of Tartu, Tartu (Estonia); Peterson, Paert [Molecular Pathology, Institute of General and Molecular Pathology, University of Tartu, 19th Ravila Str, Tartu (Estonia)

2012-08-15

The Autoimmune Regulator (AIRE) is a regulator of transcription in the thymic medulla, where it controls the expression of a large set of peripheral-tissue specific genes. AIRE interacts with the transcriptional coactivator and acetyltransferase CBP and synergistically cooperates with it in transcriptional activation. Here, we aimed to study a possible role of AIRE acetylation in the modulation of its activity. We found that AIRE is acetylated in tissue culture cells and this acetylation is enhanced by overexpression of CBP and the CBP paralog p300. The acetylated lysines were located within nuclear localization signal and SAND domain. AIRE with mutations that mimicked acetylated K243 and K253 in the SAND domain had reduced transactivation activity and accumulated into fewer and larger nuclear bodies, whereas mutations that mimicked the unacetylated lysines were functionally similar to wild-type AIRE. Analogously to CBP, p300 localized to AIRE-containing nuclear bodies, however, the overexpression of p300 did not enhance the transcriptional activation of AIRE-regulated genes. Further studies showed that overexpression of p300 stabilized the AIRE protein. Interestingly, gene expression profiling revealed that AIRE, with mutations mimicking K243/K253 acetylation in SAND, was able to activate gene expression, although the affected genes were different and the activation level was lower from those regulated by wild-type AIRE. Our results suggest that the AIRE acetylation can influence the selection of AIRE activated genes. -- Highlights: Black-Right-Pointing-Pointer AIRE is acetylated by the acetyltransferases p300 and CBP. Black-Right-Pointing-Pointer Acetylation occurs between CARD and SAND domains and within the SAND domain. Black-Right-Pointing-Pointer Acetylation increases the size of AIRE nuclear dots. Black-Right-Pointing-Pointer Acetylation increases AIRE protein stability. Black-Right-Pointing-Pointer AIRE acetylation mimic regulates a different set of AIRE

Identification of transcription coactivator OCA-B-dependent genes involved in antigen-dependent B cell differentiation by cDNA array analyses.

Science.gov (United States)

Kim, Unkyu; Siegel, Rachael; Ren, Xiaodi; Gunther, Cary S; Gaasterland, Terry; Roeder, Robert G

2003-07-22

The tissue-specific transcriptional coactivator OCA-B is required for antigen-dependent B cell differentiation events, including germinal center formation. However, the identity of OCA-B target genes involved in this process is unknown. This study has used large-scale cDNA arrays to monitor changes in gene expression patterns that accompany mature B cell differentiation. B cell receptor ligation alone induces many genes involved in B cell expansion, whereas B cell receptor and helper T cell costimulation induce genes associated with B cell effector function. OCA-B expression is induced by both B cell receptor ligation alone and helper T cell costimulation, suggesting that OCA-B is involved in B cell expansion as well as B cell function. Accordingly, several genes involved in cell proliferation and signaling, such as Lck, Kcnn4, Cdc37, cyclin D3, B4galt1, and Ms4a11, have been identified as OCA-B-dependent genes. Further studies on the roles played by these genes in B cells will contribute to an understanding of B cell differentiation.

A transcriptional coregulator, SPIN·DOC, attenuates the coactivator activity of Spindlin1.

Science.gov (United States)

Bae, Narkhyun; Gao, Min; Li, Xu; Premkumar, Tolkappiyan; Sbardella, Gianluca; Chen, Junjie; Bedford, Mark T

2017-12-22

Spindlin1 (SPIN1) is a transcriptional coactivator with critical functions in embryonic development and emerging roles in cancer. SPIN1 harbors three Tudor domains, two of which engage the tail of histone H3 by reading the H3-Lys-4 trimethylation and H3-Arg-8 asymmetric dimethylation marks. To gain mechanistic insight into how SPIN1 functions as a transcriptional coactivator, here we purified its interacting proteins. We identified an uncharacterized protein (C11orf84), which we renamed SPIN1 docking protein (SPIN·DOC), that directly binds SPIN1 and strongly disrupts its histone methylation reading ability, causing it to disassociate from chromatin. The Spindlin family of coactivators has five related members (SPIN1, 2A, 2B, 3, and 4), and we found that all of them bind SPIN·DOC. It has been reported previously that SPIN1 regulates gene expression in the Wnt signaling pathway by directly interacting with transcription factor 4 (TCF4). We observed here that SPIN·DOC associates with TCF4 in a SPIN1-dependent manner and dampens SPIN1 coactivator activity in TOPflash reporter assays. Furthermore, knockdown and overexpression experiments indicated that SPIN·DOC represses the expression of a number of SPIN1-regulated genes, including those encoding ribosomal RNA and the cytokine IL1B. In conclusion, we have identified SPIN·DOC as a transcriptional repressor that binds SPIN1 and masks its ability to engage the H3-Lys-4 trimethylation activation mark. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

DNA sequence variants in PPARGC1A, a gene encoding a coactivator of the ω-3 LCPUFA sensing PPAR-RXR transcription complex, are associated with NV AMD and AMD-associated loci in genes of complement and VEGF signaling pathways.

Directory of Open Access Journals (Sweden)

John Paul SanGiovanni

Full Text Available Increased intake of ω-3 long-chain polyunsaturated fatty acids (LCPUFAs and use of peroxisome proliferator activator receptor (PPAR-activating drugs are associated with attenuation of pathologic retinal angiogenesis. ω-3 LCPUFAs are endogenous agonists of PPARs. We postulated that DNA sequence variation in PPAR gamma (PPARG co-activator 1 alpha (PPARGC1A, a gene encoding a co-activator of the LCPUFA-sensing PPARG-retinoid X receptor (RXR transcription complex, may influence neovascularization (NV in age-related macular degeneration (AMD.We applied exact testing methods to examine distributions of DNA sequence variants in PPARGC1A for association with NV AMD and interaction of AMD-associated loci in genes of complement, lipid metabolism, and VEGF signaling systems. Our sample contained 1858 people from 3 elderly cohorts of western European ancestry. We concurrently investigated retinal gene expression profiles in 17-day-old neonatal mice on a 2% LCPUFA feeding paradigm to identify LCPUFA-regulated genes both associated with pathologic retinal angiogenesis and known to interact with PPARs or PPARGC1A.A DNA coding variant (rs3736265 and a 3'UTR-resident regulatory variant (rs3774923 in PPARGC1A were independently associated with NV AMD (exact P = 0.003, both SNPs. SNP-SNP interactions existed for NV AMD (P<0.005 with rs3736265 and a AMD-associated variant in complement factor B (CFB, rs512559. PPARGC1A influences activation of the AMD-associated complement component 3 (C3 promoter fragment and CFB influences activation and proteolysis of C3. We observed interaction (P ≤ 0.003 of rs3736265 with a variant in vascular endothelial growth factor A (VEGFA, rs3025033, a key molecule in retinal angiogenesis. Another PPARGC1A coding variant (rs8192678 showed statistical interaction with a SNP in the VEGFA receptor fms-related tyrosine kinase 1 (FLT1, rs10507386; P ≤ 0.003. C3 expression was down-regulated 2-fold in retinas of ω-3 LCPUFA-fed mice

DNA sequence variants in PPARGC1A, a gene encoding a coactivator of the ω-3 LCPUFA sensing PPAR-RXR transcription complex, are associated with NV AMD and AMD-associated loci in genes of complement and VEGF signaling pathways.

Science.gov (United States)

SanGiovanni, John Paul; Chen, Jing; Sapieha, Przemyslaw; Aderman, Christopher M; Stahl, Andreas; Clemons, Traci E; Chew, Emily Y; Smith, Lois E H

2013-01-01

Increased intake of ω-3 long-chain polyunsaturated fatty acids (LCPUFAs) and use of peroxisome proliferator activator receptor (PPAR)-activating drugs are associated with attenuation of pathologic retinal angiogenesis. ω-3 LCPUFAs are endogenous agonists of PPARs. We postulated that DNA sequence variation in PPAR gamma (PPARG) co-activator 1 alpha (PPARGC1A), a gene encoding a co-activator of the LCPUFA-sensing PPARG-retinoid X receptor (RXR) transcription complex, may influence neovascularization (NV) in age-related macular degeneration (AMD). We applied exact testing methods to examine distributions of DNA sequence variants in PPARGC1A for association with NV AMD and interaction of AMD-associated loci in genes of complement, lipid metabolism, and VEGF signaling systems. Our sample contained 1858 people from 3 elderly cohorts of western European ancestry. We concurrently investigated retinal gene expression profiles in 17-day-old neonatal mice on a 2% LCPUFA feeding paradigm to identify LCPUFA-regulated genes both associated with pathologic retinal angiogenesis and known to interact with PPARs or PPARGC1A. A DNA coding variant (rs3736265) and a 3'UTR-resident regulatory variant (rs3774923) in PPARGC1A were independently associated with NV AMD (exact P = 0.003, both SNPs). SNP-SNP interactions existed for NV AMD (Pcomplement factor B (CFB, rs512559). PPARGC1A influences activation of the AMD-associated complement component 3 (C3) promoter fragment and CFB influences activation and proteolysis of C3. We observed interaction (P ≤ 0.003) of rs3736265 with a variant in vascular endothelial growth factor A (VEGFA, rs3025033), a key molecule in retinal angiogenesis. Another PPARGC1A coding variant (rs8192678) showed statistical interaction with a SNP in the VEGFA receptor fms-related tyrosine kinase 1 (FLT1, rs10507386; P ≤ 0.003). C3 expression was down-regulated 2-fold in retinas of ω-3 LCPUFA-fed mice - these animals also showed 70% reduction in retinal NV (P �

Nuclear receptor TLX inhibits TGF-β signaling in glioblastoma

International Nuclear Information System (INIS)

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

2016-01-01

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. - Highlights: • TLX knockdown enhances TGF-β dependent Smad signaling in glioblastoma cells • TLX knockdown increases the protein level of TGF-β receptor II. • TLX stabilizes and retains Smurf1 in the cytoplasm. • TLX enhances Smurf1-dependent ubiquitination and degradation of TGF-β receptor II.

Nuclear receptor TLX inhibits TGF-β signaling in glioblastoma

Energy Technology Data Exchange (ETDEWEB)

Johansson, Erik; Zhai, Qiwei [Sahlgrenska Cancer Center at the Sahlgrenska Academy, University of Gothenburg, Box 425, SE 405 30 Gothenburg (Sweden); Zeng, Zhao-jun [Sahlgrenska Cancer Center at the Sahlgrenska Academy, University of Gothenburg, Box 425, SE 405 30 Gothenburg (Sweden); Molecular Biology Research Center, School of Life Sciences, Central South University, 110, Xiangya Road, Changsha, Hunan 410078 (China); Yoshida, Takeshi [Sahlgrenska Cancer Center at the Sahlgrenska Academy, University of Gothenburg, Box 425, SE 405 30 Gothenburg (Sweden); Funa, Keiko, E-mail: keiko.funa@gu.se [Sahlgrenska Cancer Center at the Sahlgrenska Academy, University of Gothenburg, Box 425, SE 405 30 Gothenburg (Sweden)

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. - Highlights: • TLX knockdown enhances TGF-β dependent Smad signaling in glioblastoma cells • TLX knockdown increases the protein level of TGF-β receptor II. • TLX stabilizes and retains Smurf1 in the cytoplasm. • TLX enhances Smurf1-dependent ubiquitination and degradation of TGF-β receptor II.

A nuclear-receptor-dependent phosphatidylcholine pathway with antidiabetic effects.

Science.gov (United States)

Lee, Jae Man; Lee, Yoon Kwang; Mamrosh, Jennifer L; Busby, Scott A; Griffin, Patrick R; Pathak, Manish C; Ortlund, Eric A; Moore, David D

2011-05-25

Nuclear hormone receptors regulate diverse metabolic pathways and the orphan nuclear receptor LRH-1 (also known as NR5A2) regulates bile acid biosynthesis. Structural studies have identified phospholipids as potential LRH-1 ligands, but their functional relevance is unclear. Here we show that an unusual phosphatidylcholine species with two saturated 12 carbon fatty acid acyl side chains (dilauroyl phosphatidylcholine (DLPC)) is an LRH-1 agonist ligand in vitro. DLPC treatment induces bile acid biosynthetic enzymes in mouse liver, increases bile acid levels, and lowers hepatic triglycerides and serum glucose. DLPC treatment also decreases hepatic steatosis and improves glucose homeostasis in two mouse models of insulin resistance. Both the antidiabetic and lipotropic effects are lost in liver-specific Lrh-1 knockouts. These findings identify an LRH-1 dependent phosphatidylcholine signalling pathway that regulates bile acid metabolism and glucose homeostasis.

Hepatitis C virus core protein regulates p300/CBP co-activation function. Possible role in the regulation of NF-AT1 transcriptional activity

International Nuclear Information System (INIS)

Gomez-Gonzalo, Marta; Benedicto, Ignacio; Carretero, Marta; Lara-Pezzi, Enrique; Maldonado-Rodriguez, Alejandra; Moreno-Otero, Ricardo; Lai, Michael M.C.; Lopez-Cabrera, Manuel

2004-01-01

Hepatitis C virus (HCV) core is a viral structural protein; it also participates in some cellular processes, including transcriptional regulation. However, the mechanisms of core-mediated transcriptional regulation remain poorly understood. Oncogenic virus proteins often target p300/CBP, a known co-activator of a wide variety of transcription factors, to regulate the expression of cellular and viral genes. Here we demonstrate, for the first time, that HCV core protein interacts with p300/CBP and enhances both its acetyl-transferase and transcriptional activities. In addition, we demonstrate that nuclear core protein activates the NH 2 -terminal transcription activation domain (TAD) of NF-AT1 in a p300/CBP-dependent manner. We propose a model in which core protein regulates the co-activation function of p300/CBP and activates NF-AT1, and probably other p300/CBP-regulated transcription factors, by a novel mechanism involving the regulation of the acetylation state of histones and/or components of the transcriptional machinery

Maturing of the nuclear receptor family.

Science.gov (United States)

Lazar, Mitchell A

2017-04-03

Members of the nuclear receptor (NR) superfamily of ligand-regulated transcription factors play important roles in reproduction, development, and physiology. In humans, genetic mutations in NRs are causes of rare diseases, while hormones and drugs that target NRs are in widespread therapeutic use. The present issue of the JCI includes a series of Review articles focused on specific NRs and their wide range of biological functions. Here I reflect on the past, present, and potential future highlights of research on the NR superfamily.

Localización extra nuclear de receptores esteroides y activación de mecanismos no genómicos Extra nuclear localization of steroid receptors and non genomic activation mechanisms

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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.

Disruption of histone modification and CARM1 recruitment by arsenic represses transcription at glucocorticoid receptor-regulated promoters.

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Barr, Fiona D; Krohmer, Lori J; Hamilton, Joshua W; Sheldon, Lynn A

2009-08-26

Chronic exposure to inorganic arsenic (iAs) found in the environment is one of the most significant and widespread environmental health risks in the U.S. and throughout the world. It is associated with a broad range of health effects from cancer to diabetes as well as reproductive and developmental anomalies. This diversity of diseases can also result from disruption of metabolic and other cellular processes regulated by steroid hormone receptors via aberrant transcriptional regulation. Significantly, exposure to iAs inhibits steroid hormone-mediated gene activation. iAs exposure is associated with disease, but is also used therapeutically to treat specific cancers complicating an understanding of iAs action. Transcriptional activation by steroid hormone receptors is accompanied by changes in histone and non-histone protein post-translational modification (PTM) that result from the enzymatic activity of coactivator and corepressor proteins such as GRIP1 and CARM1. This study addresses how iAs represses steroid receptor-regulated gene transcription. PTMs on histones H3 and H4 at the glucocorticoid receptor (GR)-activated mouse mammary tumor virus (MMTV) promoter were identified by chromatin immunoprecipitation analysis following exposure to steroid hormone+/-iAs. Histone H3K18 and H3R17 amino acid residues had significantly different patterns of PTMs after treatment with iAs. Promoter interaction of the coactivator CARM1 was disrupted, but the interaction of GRIP1, a p160 coactivator through which CARM1 interacts with a promoter, was intact. Over-expression of CARM1 was able to fully restore and GRIP1 partially restored iAs-repressed transcription indicating that these coactivators are functionally associated with iAs-mediated transcriptional repression. Both are essential for robust transcription at steroid hormone regulated genes and both are associated with disease when inappropriately expressed. We postulate that iAs effects on CARM1 and GRIP1 may underlie some

Coactive Design : Designing Support for Interdependence in Joint Activity

NARCIS (Netherlands)

Johnson, M.; Bradshaw, J.M.; Feltovich, P.J.; Jonker, C.M.; Van Riemsdijk, M.B.; Sierhuis, M.

2014-01-01

Coactive Design is a new approach to address the increasingly sophisticated roles that people and robots play as the use of robots expands into new, complex domains. The approach is motivated by the desire for robots to perform less like teleoperated tools or independent automatons and more like

Nuclear hormone receptor expression in mouse kidney and renal cell lines.

Directory of Open Access Journals (Sweden)

Daisuke Ogawa

Full Text Available Nuclear hormone receptors (NHRs are transcription factors that regulate carbohydrate and lipid metabolism, immune responses, and inflammation. Although several NHRs, including peroxisome proliferator-activated receptor-γ (PPARγ and PPARα, demonstrate a renoprotective effect in the context of diabetic nephropathy (DN, the expression and role of other NHRs in the kidney are still unrecognized. To investigate potential roles of NHRs in the biology of the kidney, we used quantitative real-time polymerase chain reaction to profile the expression of all 49 members of the mouse NHR superfamily in mouse kidney tissue (C57BL/6 and db/m, and cell lines of mesangial (MES13, podocyte (MPC, proximal tubular epithelial (mProx24 and collecting duct (mIMCD3 origins in both normal and high-glucose conditions. In C57BL/6 mouse kidney cells, hepatocyte nuclear factor 4α, chicken ovalbumin upstream promoter transcription factor II (COUP-TFII and COUP-TFIII were highly expressed. During hyperglycemia, the expression of the NHR 4A subgroup including neuron-derived clone 77 (Nur77, nuclear receptor-related factor 1, and neuron-derived orphan receptor 1 significantly increased in diabetic C57BL/6 and db/db mice. In renal cell lines, PPARδ was highly expressed in mesangial and proximal tubular epithelial cells, while COUP-TFs were highly expressed in podocytes, proximal tubular epithelial cells, and collecting duct cells. High-glucose conditions increased the expression of Nur77 in mesangial and collecting duct cells, and liver x receptor α in podocytes. These data demonstrate NHR expression in mouse kidney cells and cultured renal cell lines and suggest potential therapeutic targets in the kidney for the treatment of DN.

Vascular risk factor burden correlates with cerebrovascular reactivity but not resting state coactivation in the default mode network.

Science.gov (United States)

Tchistiakova, Ekaterina; Crane, David E; Mikulis, David J; Anderson, Nicole D; Greenwood, Carol E; Black, Sandra E; MacIntosh, Bradley J

2015-11-01

White matter hyperintensities (WMH) are prevalent among older adults and are often associated with cognitive decline and increased risk of stroke and dementia. Vascular risk factors (VRFs) are linked to WMH, yet the impact of multiple VRFs on gray matter function is still unclear. The goal of this study was to test for associations between the number of VRFs and cerebrovascular reactivity (CVR) and resting state (RS) coactivation among individuals with WMH. Twenty-nine participants with suspected WMH were grouped based on the number of VRFs (subgroups: 0, 1, or ≥2). CVR and RS coactivation were measured with blood oxygenation level-dependent (BOLD) imaging on a 3T magnetic resonance imaging (MRI) system during hypercapnia and rest, respectively. Default-mode (DMN), sensory-motor, and medial-visual networks, generated using independent component analysis of RS-BOLD, were selected as networks of interest (NOIs). CVR-BOLD was analyzed using two methods: 1) a model-based approach using CO2 traces, and 2) a dual-regression (DR) approach using NOIs as spatial inputs. Average CVR and RS coactivations within NOIs were compared between VRF subgroups. A secondary analysis investigated the correlation between CVR and RS coactivation. VRF subgroup differences were detected using DR-based CVR in the DMN (F20,2  = 5.17, P = 0.015) but not the model-based CVR nor RS coactivation. DR-based CVR was correlated with RS coactivation in the DMN (r(2)  = 0.28, P = 0.006) but not the sensory-motor nor medial-visual NOIs. In individuals with WMH, CVR in the DMN was inversely associated with the number of VRFs and correlated with RS coactivation. © 2015 Wiley Periodicals, Inc.

Nuclear androgen receptors in human prostatic tissue. Extraction with heparin and estimation of the number of binding sites with different methods

International Nuclear Information System (INIS)

Foekens, J.A.; Bolt-de Vries, J.; Mulder, E.; Blankenstein, M.A.; Schroeder, F.H.; Molen, H.J. van der

1981-01-01

A procedure for the estimation of nuclear androgen receptors in benign prostatic hyperplastic tissue is described, which employs extraction of receptors from nuclei with buffers containing heparin. Extraction of a nuclear pellet with a heparin-containing (1 g/l) buffer appeared to have definite advantages over 0.4 mol/l KCl extraction. Heparin appeared to be twice as efficient in extracting androgen receptors. In addition aggregated receptor proteins, formed after storage at -80 0 C, were partly deaggregated by heparin. Specific isolation of the androgen receptor was performed using either agar gel electrophoresis, protamine sulphate precipitation or LH-20 gel filtration. A comparison was made between the amounts of estimated receptors with these different techniques. Protamine sulphate precipitation resulted in the highest estimates of receptor-bound 5α-[ 3 H]dihydrotestosterone ( 3 H-DHT). Treatment of the labelled nuclear extracts with a charcoal suspension prior to the receptor assay resulted in lower amounts of estimated androgen receptors. A method for routine evaluation of nuclear androgen receptors in prostatic tissue has been evaluated, which involves extraction of nuclear pellets with a heparin-containing (1 g/l) buffer, exchange labelling of the nuclear extracts for 20 h at 10 0 C and quantification of the receptors with protamine sulphate precipitation. (Auth.)

Functional relevance of neurotransmitter receptor heteromers in the central nervous system.

Science.gov (United States)

Ferré, Sergi; Ciruela, Francisco; Woods, Amina S; Lluis, Carme; Franco, Rafael

2007-09-01

The existence of neurotransmitter receptor heteromers is becoming broadly accepted and their functional significance is being revealed. Heteromerization of neurotransmitter receptors produces functional entities that possess different biochemical characteristics with respect to the individual components of the heteromer. Neurotransmitter receptor heteromers can function as processors of computations that modulate cell signaling. Thus, the quantitative or qualitative aspects of the signaling generated by stimulation of any of the individual receptor units in the heteromer are different from those obtained during coactivation. Furthermore, recent studies demonstrate that some neurotransmitter receptor heteromers can exert an effect as processors of computations that directly modulate both pre- and postsynaptic neurotransmission. This is illustrated by the analysis of striatal receptor heteromers that control striatal glutamatergic neurotransmission.

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.

Combined therapeutic potential of nuclear receptors with receptor tyrosine kinase inhibitors in lung cancer

International Nuclear Information System (INIS)

Wairagu, Peninah M.; Park, Kwang Hwa; Kim, Jihye; Choi, Jong-Whan; Kim, Hyun-Won; Yeh, Byung-Il; Jung, Soon-Hee; Yong, Suk-Joong; Jeong, Yangsik

2014-01-01

Highlights: • The 48 NR genes and 48 biological anti-cancer targets are profiled in paired-cells. • Growth inhibition by NR ligands or TKIs is target receptor level-dependent. • T0901317 with gefitinib/PHA665752 shows additive growth inhibition in lung cells. - Abstract: Cancer heterogeneity is a big hurdle in achieving complete cancer treatment, which has led to the emergence of combinational therapy. In this study, we investigated the potential use of nuclear receptor (NR) ligands for combinational therapy with other anti-cancer drugs. We first profiled all 48 NRs and 48 biological anti-cancer targets in four pairs of lung cell lines, where each pair was obtained from the same patient. Two sets of cell lines were normal and the corresponding tumor cell lines while the other two sets consisted of primary versus metastatic tumor cell lines. Analysis of the expression profile revealed 11 NRs and 15 cancer targets from the two pairs of normal versus tumor cell lines, and 9 NRs and 9 cancer targets from the primary versus metastatic tumor cell lines had distinct expression patterns in each category. Finally, the evaluation of nuclear receptor ligand T0901317 for liver X receptor (LXR) demonstrated its combined therapeutic potential with tyrosine kinase inhibitors. The combined treatment of cMET inhibitor PHA665752 or EGFR inhibitor gefitinib with T0901317 showed additive growth inhibition in both H2073 and H1993 cells. Mechanistically, the combined treatment suppressed cell cycle progression by inhibiting cyclinD1 and cyclinB expression. Taken together, this study provides insight into the potential use of NR ligands in combined therapeutics with other biological anti-cancer drugs

IGF-II-mediated downregulation of peroxisome proliferator-activated receptor-γ coactivator-1α in myoblast cells involves PI3K/Akt/FoxO1 signaling pathway.

Science.gov (United States)

Mu, Xiaoyu; Qi, Weihong; Liu, Yunzhang; Zhou, Jianfeng; Li, Yun; Rong, Xiaozhi; Lu, Ling

2017-08-01

Insulin-like growth factor II (IGF-II) can stimulate myogenesis and is critically involved in skeletal muscle differentiation. The presence of negative regulators of this process, however, is not well explored. Here, we showed that in myoblast cells, IGF-II negatively regulated peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mRNA expression, while constitutive expression of PGC-1α induced myoblast differentiation. These results suggest that the negative regulation of PGC-1α by IGF-II may act as a negative feedback mechanism in IGF-II-induced myogenic differentiation. Reporter assays demonstrated that IGF-II suppresses the basal PGC-1α promoter activity. Blocking the IGF-II signaling pathway increased the endogenous PGC-1α levels. In addition, pharmacological inhibition of PI3 kinase activity prevented the downregulation of PGC-1α but the activation of mTOR was not required for this process. Importantly, further analysis showed that forkhead transcription factor FoxO1 contributes to mediating the effects of IGF-II on PGC-1 promoter activity. These findings indicate that IGF-II reduces PGC-1α expression in skeletal muscle cells through a mechanism involving PI3K-Akt-FoxO1 but not p38 MAPK or Erk1/2 MAPK pathways.

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.

The molecular mechanism of bisphenol A (BPA as an endocrine disruptor by interacting with nuclear receptors: insights from molecular dynamics (MD simulations.

Directory of Open Access Journals (Sweden)

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.

Rapid, portable detection of endocrine disrupting chemicals through ligand-nuclear hormone receptor interactions.

Science.gov (United States)

Hunt, J Porter; Schinn, Song-Min; Jones, Matthew D; Bundy, Bradley C

2017-12-04

Endocrine disrupting chemicals (EDC) are structurally diverse compounds that can interact with nuclear hormone receptors, posing significant risk to human and ecological health. Unfortunately, many conventional biosensors have been too structure-specific, labor-intensive or laboratory-oriented to detect broad ranges of EDC effectively. Recently, several technological advances are providing more rapid, portable, and affordable detection of endocrine-disrupting activity through ligand-nuclear hormone receptor interactions. Here, we overview these recent advances applied to EDC biosensors - including cell lyophilization, cell immobilization, cell-free systems, smartphone-based signal detection, and improved competitive binding assays.

Inverse antagonist activities of parabens on human oestrogen-related receptor γ (ERRγ): In vitro and in silico studies

International Nuclear Information System (INIS)

Zhang, Zhaobin; Sun, Libei; Hu, Ying; Jiao, Jian; Hu, Jianying

2013-01-01

Parabens are p-hydroxybenzoic acid esters that have been used extensively as preservatives in foods, cosmetics, drugs and toiletries. These intact esters are commonly detected in human breast cancer tissues and other human samples, thus arousing concern about the involvement of parabens in human breast cancer. In this study, an in vitro nuclear receptor coactivator recruiting assay was developed and used to evaluate the binding activities of parabens, salicylates and benzoates via antagonist competitive binding on the human oestrogen-related receptor γ (ERRγ), which is known as both a diagnostic biomarker and a treatment target of breast cancer. The results showed that all of the test parabens (methyl-, ethyl-, propyl-, butyl- and benzylparaben) possessed clear inverse antagonist activities on ERRγ, with a lowest observed effect level (LOEL) of 10 −7 M and the 50% relative effective concentrations (REC50) varying from 3.09 × 10 −7 to 5.88 × 10 −7 M, whereas the salicylates possessed much lower activities and the benzoates showed no obvious activity. In silico molecular docking analyses showed that parabens fitted well into the active site of ERRγ, with hydrogen bonds forming between the p-hydroxyl group of parabens and the Glu275/Arg316 of ERRγ. As the paraben levels reported in breast cancer tissues are commonly higher than the LOELs observed in this study, parabens may play some role via ERRγ in the carcinogenesis of human breast cancer. In addition, parabens may have significant effects on breast cancer patients who are taking tamoxifen, as ERRγ is regarded as a treatment target for tamoxifen. - Highlights: • An oestrogen-related receptor γ coactivator recruiting assay was developed. • Strong binding activities of parabens with oestrogen-related receptor γ were found. • The paraben levels reported in breast cancer tissues were higher than their LOELs. • Parabens may play some role via ERRγ in the carcinogenesis of human breast cancer. �

Modulation of thyroid hormone receptor transactivation by the early region 1A (E1A-like inhibitor of differentiation 1 (EID1

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Diana Vargas

2008-01-01

Full Text Available Transcriptional activation (TA mediated by the effect of thyroid hormones on target genes requires co-activator proteins such as the early region 1A (E1A associated 300 kDa binding protein (p300 and the cAMP response element binding protein (CREB binding protein (CBP, known as the p300/CBP complex, which acetylate histones 3 and 4 to allow transcriptional machinery access to the target gene promoter. Little is known on the role of p300 in thyroid hormone receptor (TR mediated TA but the E1A-like inhibitor of differentiation 1 (EID1, an inhibitor of p300 histone acetyltransferase (HAT, is a functional homolog of E1A and may inhibit myogenic differentiation factor D (MyoD transcriptional activity and reduces muscle cell differentiation. We evaluated the influence of EID1 on TR-mediated transcriptional activity using transfection and mammalian two-hybrid studies to show that EID1 may partially reduces TA activity of the TR receptor, probably due to p300 blockage since EID1 mutants cannot reduce TR-mediated TA. The EID1 does not affect the function of p160 co-activator proteins (160 kDa proteins of steroid receptor co-activators and is functionally independent of co-repressor proteins or TR binding. Summarizing, EID1 reduces TR-mediated transcriptional activity by blocking p300 and may play an important role in thyroid receptor activity in muscle and other tissues.

Unmanned Tactical Autonomous Control and Collaboration Coactive Design

Science.gov (United States)

2016-06-01

process. When modeling processes with a waterfall design, the requirements are mostly understood upfront and allow developers to move on to subsequent...processes when modeling the system. As such, the focus is shifted to supplementing team capacities vice developing autonomy. The two aims of this...development method, Coactive Design. An advantage to using this method is that it includes the human and his or her internal processes when modeling the

Three nuclear and two membrane estrogen receptors in basal teleosts, Anguilla sp.: Identification, evolutionary history and differential expression regulation

DEFF Research Database (Denmark)

Lafont, Anne Gaëlle; Rousseau, Karine; Tomkiewicz, Jonna

2016-01-01

Estrogens interact with classical intracellular nuclear receptors (ESR), and with G-coupled membrane receptors (GPER). In the eel, we identified three nuclear (ESR1, ESR2a, ESR2b) and two membrane (GPERa, GPERb) estrogen receptors. Duplicated ESR2 and GPER were also retrieved in most extant teleo...

Ligands specify estrogen receptor alpha nuclear localization and degradation

Directory of Open Access Journals (Sweden)

Caze-Subra Stéphanie

2010-12-01

Full Text Available Abstract Background The estrogen receptor alpha (ERα is found predominately in the nucleus, both in hormone stimulated and untreated cells. Intracellular distribution of the ERα changes in the presence of agonists but the impact of different antiestrogens on the fate of ERα is a matter of debate. Results A MCF-7 cell line stably expressing GFP-tagged human ERα (SK19 cell line was created to examine the localization of ligand-bound GFP-ERα. We combined digitonin-based cell fractionation analyses with fluorescence and immuno-electron microscopy to determine the intracellular distribution of ligand-bound ERα and/or GFP-ERα. Using fluorescence- and electron microscopy we demonstrate that both endogenous ERα and GFP-ERα form numerous nuclear focal accumulations upon addition of agonist, 17β-estradiol (E2, and pure antagonists (selective estrogen regulator disruptor; SERD, ICI 182,780 or RU58,668, while in the presence of partial antagonists (selective estrogen regulator modulator; SERM, 4-hydroxytamoxifen (OHT or RU39,411, diffuse nuclear staining persisted. Digitonin based cell fractionation analyses confirmed that endogenous ERα and GFP-ERα predominantly reside in the nuclear fraction. Overall ERα protein levels were reduced after estradiol treatment. In the presence of SERMs ERα was stabilized in the nuclear soluble fraction, while in the presence of SERDs protein levels decreased drastically and the remaining ERα was largely found in a nuclear insoluble fraction. mRNA levels of ESR1 were reduced compared to untreated cells in the presence of all ligands tested, including E2. E2 and SERDs induced ERα degradation occurred in distinct nuclear foci composed of ERα and the proteasome providing a simple explanation for ERα sequestration in the nucleus. Conclusions Our results indicate that chemical structure of ligands directly affect the nuclear fate and protein turnover of the estrogen receptor alpha independently of their impact on

Spatial profiling of nuclear receptor transcription patterns over the course of Drosophila development.

Science.gov (United States)

Wilk, Ronit; Hu, Jack; Krause, Henry M

2013-07-08

Previous work has shown that many of the 18 family members of Drosophila nuclear receptor transcription factors function in a temporal hierarchy to coordinate developmental progression and growth with the rate limiting process of metabolism. To gain further insight into these interactions and processes, we have undertaken a whole-family analysis of nuclear receptor mRNA spatial expression patterns over the entire process of embryogenesis, as well as the 3rd instar wandering larva stage, by using high-resolution fluorescence in situ hybridization. Overall, the patterns of expression are remarkably consistent with previously mapped spatial activity profiles documented during the same time points, with similar hot spots and temporal profiles in endocrine and metabolically important tissues. Among the more remarkable of the findings is that the majority of mRNA expression patterns observed show striking subcellular distributions, indicating potentially critical roles in the control of protein synthesis and subsequent subcellular distributions. These patterns will serve as a useful reference for future studies on the tissue-specific roles and interactions of nuclear receptor proteins, partners, cofactors and ligands.

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. Copyright © 2016. Published by Elsevier Inc.

Nuclear triiodothyronine receptors in rabbit heart

International Nuclear Information System (INIS)

Banerjee, S.K.; Ulrich, J.M.; Kaldor, G.J.

1986-01-01

Nuclear triiodothyronine receptors from rat liver have been characterized in detail by several investigators. However, little work has been done in this area using heart tissue. In this study they examined and characterized the triiodothyronine binding in rabbit hearts. Nuclei have been prepared from ventricular muscle cells of normal and thyrotoxic rabbits as well as from atrial muscle cells of normal rabbit. Hearts were perfused with a minimum essential medium containing collagenase and bovine serum albumin. Myocardial cells were isolated and then disrupted by sonication and washing with a Triton X-100 buffer solution. A discontinuous sucrose density gradient was then used to isolate the mycoardial nuclei. Radiolabelled triiodothyronine (T 3 ) binding to nuclei was examined using conditions described by established procedures. Scatchard analysis of the binding data yields maximum binding capacity (B/sub max/) of 0.17 +/- 0.2 pmol/mg DNA and apparent dissociation constant (K/sub d/) of 400 +/- 50 pM for normal heart T 3 -receptors. The apparent capacity for T 3 binding is approximately 40% greater in myocardial nuclei prepared from hearts of hyperthyroid rabbits. The binding capacity of atrial muscle nuclei is about fourfold lower than ventricular cell nuclei. The results suggest that binding capacity for T 3 -receptor in the atrium is considerably lower than that found in the ventricle

Over-accumulation of nuclear IGF-1 receptor in tumor cells requires elevated expression of the receptor and the SUMO-conjugating enzyme Ubc9

Energy Technology Data Exchange (ETDEWEB)

Deng, Hua; Lin, Yingbo; Badin, Margherita; Vasilcanu, Daiana; Stroemberg, Thomas [Department of Oncology and Pathology, The Karolinska Institute, Cancer Center Karolinska, SE-17176 Stockholm (Sweden); Jernberg-Wiklund, Helena [Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala (Sweden); Sehat, Bita [Department of Oncology and Pathology, The Karolinska Institute, Cancer Center Karolinska, SE-17176 Stockholm (Sweden); Larsson, Olle, E-mail: olle.larsson@ki.se [Department of Oncology and Pathology, The Karolinska Institute, Cancer Center Karolinska, SE-17176 Stockholm (Sweden)

2011-01-14

Research highlights: {yields} SUMOylation mediates nuclear translocation of IGF-1R which activates transcription. {yields} Here we show that nuclear IGF-1R over-accumulates in tumor cells. {yields} This requires overexpression of the receptor that is a common feature in tumor cells. {yields} An increased expression of the SUMO ligase Ubc9 seems to be an involved mechanism too. -- Abstract: The insulin-like growth factor 1 receptor (IGF-1R) plays crucial roles in tumor cell growth and is overexpressed in many cancers. IGF-1R's trans-membrane kinase signaling pathways have been well characterized. Very recently, we showed that SUMOylation mediates nuclear translocation of the IGF-1R, and that nuclear IGF-1R (nIGF-1R) binds to enhancer regions and activates transcription. We identified three lysine residues in the {beta}-subunit of the receptor and that mutation of these blocks nuclear translocation and gene activation. Furthermore, accumulation of nIGF-1R was proven strongly dependent on the specific SUMO-conjugating enzyme Ubc9. Here we show that nIGF-1R originates solely from the cell membrane and that phosphorylation of the core tyrosine residues of the receptor kinase is crucial for nuclear accumulation. We also compared the levels of nIGF-1R, measured as nuclear/membrane ratios, in tumor and normal cells. We found that the breast cancer cell line MCF-7 has 13-fold higher amounts of nIGF-1R than breast epithelial cells (IME) which showed only a small amount of nIGF-1R. In comparison, the total expression of IGF-1R was only 3.7- higher in MCF-7. Comparison of several other tumor and normal cell lines showed similar tumor cell over-accumulation of nIGF-1R, exceeding the total receptor expression substantially. Ectopic overexpression (>10-fold) of the receptor increased nIGF-1R in IME cells but not to that high level as in wild type MCF-7. The levels of Ubc9 were higher in all tumor cell lines, compared to the normal cells, and this probably contributes to over

Over-accumulation of nuclear IGF-1 receptor in tumor cells requires elevated expression of the receptor and the SUMO-conjugating enzyme Ubc9

International Nuclear Information System (INIS)

Deng, Hua; Lin, Yingbo; Badin, Margherita; Vasilcanu, Daiana; Stroemberg, Thomas; Jernberg-Wiklund, Helena; Sehat, Bita; Larsson, Olle

2011-01-01

Research highlights: → SUMOylation mediates nuclear translocation of IGF-1R which activates transcription. → Here we show that nuclear IGF-1R over-accumulates in tumor cells. → This requires overexpression of the receptor that is a common feature in tumor cells. → An increased expression of the SUMO ligase Ubc9 seems to be an involved mechanism too. -- Abstract: The insulin-like growth factor 1 receptor (IGF-1R) plays crucial roles in tumor cell growth and is overexpressed in many cancers. IGF-1R's trans-membrane kinase signaling pathways have been well characterized. Very recently, we showed that SUMOylation mediates nuclear translocation of the IGF-1R, and that nuclear IGF-1R (nIGF-1R) binds to enhancer regions and activates transcription. We identified three lysine residues in the β-subunit of the receptor and that mutation of these blocks nuclear translocation and gene activation. Furthermore, accumulation of nIGF-1R was proven strongly dependent on the specific SUMO-conjugating enzyme Ubc9. Here we show that nIGF-1R originates solely from the cell membrane and that phosphorylation of the core tyrosine residues of the receptor kinase is crucial for nuclear accumulation. We also compared the levels of nIGF-1R, measured as nuclear/membrane ratios, in tumor and normal cells. We found that the breast cancer cell line MCF-7 has 13-fold higher amounts of nIGF-1R than breast epithelial cells (IME) which showed only a small amount of nIGF-1R. In comparison, the total expression of IGF-1R was only 3.7- higher in MCF-7. Comparison of several other tumor and normal cell lines showed similar tumor cell over-accumulation of nIGF-1R, exceeding the total receptor expression substantially. Ectopic overexpression (>10-fold) of the receptor increased nIGF-1R in IME cells but not to that high level as in wild type MCF-7. The levels of Ubc9 were higher in all tumor cell lines, compared to the normal cells, and this probably contributes to over-accumulation of nIGF-1R

Novel Polymorphisms of Adrenergic, Alpha-1B-, Receptor and Peroxisome Proliferator-activated Receptor Gamma, Coactivator 1 Beta Genes and Their Association with Egg Production Traits in Local Chinese Dagu Hens

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F. Mu

2016-09-01

Full Text Available Adrenergic, alpha-1B-, receptor (ADRA1B and peroxisome proliferator-activated receptor gamma, coactivator 1 beta (PPARGC1B genes are involved in regulation of hen ovarian development. In this study, these two genes were investigated as possible molecular markers associated with hen-housed egg production, egg weight (EW and body weight in Chinese Dagu hens. Samples were analyzed using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP technique, followed by sequencing analysis. Two novel single nucleotide polymorphisms (SNPs were identified within the candidate genes. Among them, an A/G transition at base position 1915 in exon 2 of ADRA1B gene and a T/C mutation at base position 6146 in the 3′-untranslated region (UTR of PPARGC1B gene were found to be polymorphic and named SNP A1915G and T6146C, respectively. The SNP A1915G (ADRA1B leads to a non-synonymous substitution (aspartic acid 489-to-glycine. The 360 birds from the Dagu population were divided into genotypes AA and AG, allele A was found to be present at a higher frequency. Furthermore, the AG genotype correlated with significantly higher hen-housed egg production (HHEP at 30, 43, 57, and 66 wks of age and with a higher EW at 30 and 43 wks (p<0.05. For the SNP T6146C (PPARGC1B, the hens were typed into TT and TC genotypes, with the T allele shown to be dominant. The TC genotype was also markedly correlated with higher HHEP at 57 and 66 wks of age and EW at 30 and 43 wks (p<0.05. Moreover, four haplotypes were reconstructed based on these two SNPs, with the AGTC haplotype found to be associated with the highest HHEP at 30 to 66 wks of age and with higher EW at 30 and 43 wks (p<0.05. Collectively, the two SNPs identified in this study might be used as potential genetic molecular markers favorable in the improvement of egg productivity in chicken breeding.

RECEPTORES NUCLEARES: DEL NÚCLEO AL CITOPLASMA

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Bibiana Ortega-Domínguez

2015-01-01

Full Text Available Los receptores nucleares (RNs constituyen una familia de factores transcripcionales activados por ligando que regulan la expresión de un gran número de genes de forma dependiente del tipo y contexto celular. La localización subcelular de los RNs es altamente dinámica y repercute sobre sus funciones como factores transcripcionales. En presencia de su ligando específico, los RNs se acumulan en el núcleo para modular la expresión de sus genes blanco. Por ende, la salida desde el núcleo a citoplasma de los RNs disminuye su acumulación nuclear y abate su actividad transcripcional. Por lo tanto, la exportación nuclear constituye un importante mecanismo de regulación de la actividad de los RNs. A pesar de su importancia, el proceso de exportación nuclear de los RNs no ha sido completamente explorado, sin embargo, los estudios que se tienen hasta ahora sugieren la participación de las proteínas CRM–1 y la Calreticulina (CRT como mediadoras de este proceso. En esta revisión se destaca la exportación nuclear como un mecanismo regulador de las funciones de los RNs y se discuten las características estructurales y funcionales de las exportinas CRM–1 y CRT.

Proactive and coactive interference in age-related performance in a recognition-based operation span task.

Science.gov (United States)

Zeintl, Melanie; Kliegel, Matthias

2010-01-01

Generally, older adults perform worse than younger adults in complex working memory span tasks. So far, it is unclear which processes mainly contribute to age-related differences in working memory span. The aim of the present study was to investigate age effects and the roles of proactive and coactive interference in a recognition-based version of the operation span task. Younger and older adults performed standard versions and distracter versions of the operation span task. At retrieval, participants had to recognize target words in word lists containing targets as well as proactive and/or coactive interference-related lures. Results show that, overall, younger adults outperformed older adults in the recognition of target words. Furthermore, analyses of error types indicate that, while younger adults were only affected by simultaneously presented distracter words, older adults had difficulties with both proactive and coactive interference. Results suggest that age effects in complex span tasks may not be mainly due to retrieval deficits in old age. Copyright 2009 S. Karger AG, Basel.

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

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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...

Nuclear thyroid hormone receptors in rabbit heart: reduced triiodothyronine binding in atrium compared with ventricle

International Nuclear Information System (INIS)

Banerjee, S.K.; Ulrich, J.M.; Kaldor, G.J.

1988-01-01

Radiolabeled triiodothyronine (T3) binding to isolated nuclei was measured to compare the binding characteristics of the nuclear receptors in rabbit ventricular and atrial muscle cells. Scatchard analysis of the binding data yielded a maximum binding capacity of 170 +/- 20 fmol per mg DNA and apparent dissociation constant of 525 +/- 100 pM for ventricular nuclei. The binding capacity and the dissociation constant for the atrial muscle cell nuclei were 55 +/- 10 fmol per mg DNA and 500 +/- 75 pM, respectively. The results suggest that the binding capacity for T3 receptor in the atrium is considerably lower than that found in the ventricle. The reduced binding capacity of the T3 receptor in the atrium might reflect differences in the nuclear T3 receptors between ventricle and atrium

Targeted disruption of the CREB coactivator Crtc2 increases insulin sensitivity

DEFF Research Database (Denmark)

Wang, Yiguo; Inoue, Hiroshi; Ravnskjær, Kim

2010-01-01

Under fasting conditions, increases in circulating concentrations of pancreatic glucagon maintain glucose homeostasis through induction of gluconeogenic genes by the CREB coactivator CRTC2. Hepatic CRTC2 activity is elevated in obesity, although the extent to which this cofactor contributes to at...

Cold exposure rapidly induces virtual saturation of brown adipose tissue nuclear T3 receptors

International Nuclear Information System (INIS)

Bianco, A.C.; Silva, J.E.

1988-01-01

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'-triiodothyronine (T 3 ), it is necessary to cause systemic hyperthyroidism. In contrast, the same result can be obtained with just replacement doses of thyroxine (T 4 ) and, in euthyroid rats, the normal response of UCP to cold occurs without hyperthyroid plasma T 3 levels. Consequently, the authors explored the possibility that the cold-induced activation of the type II 5'-deiodinase resulted in high levels of nuclear T 3 receptor occupancy in euthyroid rats. Studies were performed with pulse injections of tracer T 3 or T 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 [ 125 I]T 3 derived from the tracer [ 125 I]T 4 injections (T 3 [T 4 ]) and a significant reduction in the nuclear [ 125 I]T 3 derived from [ 125 I]T 3 injections (T 3 [T 3 ]). The number of BAT nuclear T 3 receptors did not increase for up to 3 wk of observation at 4 degree C. The mass of nuclear-bound T 3 was calculated from the nuclear tracer [ 125 I]T 3 [T 3 ] and [ 125 I]T 3 [T 4 ] at equilibrium and the specific activity of serum T 3 and T 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 3 receptors. This makes possible the realization of the full thermogenic potential of the tissue without causing systemic hyperthyroidism

The role of nuclear hormone receptors in cutaneous wound repair.

Science.gov (United States)

Rieger, Sandra; Zhao, Hengguang; Martin, Paige; Abe, Koichiro; Lisse, Thomas S

2015-01-01

The cutaneous wound repair process involves balancing a dynamic series of events ranging from inflammation, oxidative stress, cell migration, proliferation, survival and differentiation. A complex series of secreted trophic factors, cytokines, surface and intracellular proteins are expressed in a temporospatial manner to restore skin integrity after wounding. Impaired initiation, maintenance or termination of the tissue repair processes can lead to perturbed healing, necrosis, fibrosis or even cancer. Nuclear hormone receptors (NHRs) in the cutaneous environment regulate tissue repair processes such as fibroplasia and angiogenesis. Defects in functional NHRs and their ligands are associated with the clinical phenotypes of chronic non-healing wounds and skin endocrine disorders. The functional relationship between NHRs and skin niche cells such as epidermal keratinocytes and dermal fibroblasts is pivotal for successful wound closure and permanent repair. The aim of this review is to delineate the cutaneous effects and cross-talk of various nuclear receptors upon injury towards functional tissue restoration. Copyright © 2014 John Wiley & Sons, Ltd.

PPARa and PPAR¿ coactivation rapidly induces Egr-1 in the nuclei of the dorsal and ventral urinary bladder and kidney pelvis urothelium of rats

DEFF Research Database (Denmark)

Egerod, Frederikke Lihme; Svendsen, Jette Eldrup; Hinley, Jennifer

2009-01-01

in the dorsal and ventral bladder urothelium, arguing against involvement of urinary solids. Egr-1 induction sometimes occurred in a localized fashion, indicating physiological microheterogeneity in the urothelium. The rapid kinetics supported that Egr-1 induction occurred as a result of pharmacological...... activation of PPAR alpha and PPAR gamma, which are coexpressed at high levels in the rat urothelium. Finally, our demonstration of a nuclear localization supports that the Egr-1 induced by PPAR alpha and PPAR gamma coactivation in the rat urothelium may be biologically active....

Differential coactivation in a redundant signals task with weak and strong go/no-go stimuli

DEFF Research Database (Denmark)

Minakata, Katsumi; Gondan, Matthias

2018-01-01

When participants respond to stimuli of two sources, response times (RT) are often faster when both stimuli are presented together relative to the RTs obtained when presented separately (redundant signals effect, RSE). Race models and coactivation models can explain the RSE. In race models......, separate channels process the two stimulus components, and the faster processing time determines the overall RT. In audiovisual experiments, the RSE is often higher than predicted by race models, and coactivation models have been proposed that assume integrated processing of the two stimuli. Where does...

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

Diabetes and obesity treatment based on dual incretin receptor activation

DEFF Research Database (Denmark)

Skow, M A; Bergmann, N C; Knop, F K

2016-01-01

, whereas GIP seems to affect lipid metabolism. The introduction of selective GLP-1 receptor (GLP-1R) agonists for the treatment of type 2 diabetes and obesity has increased the scientific and clinical interest in incretins. Combining the body weight-lowering and glucose-lowering effects of GLP-1...... with a more potent improvement of β cell function through additional GIP action could potentially offer a more effective treatment of diabetes and obesity, with fewer adverse effects than selective GLP-1R agonists; therefore, new drugs designed to co-activate both the GIP receptor (GIPR) and the GLP-1R...

The antidepressant fluoxetine normalizes the nuclear glucocorticoid receptor evoked by psychosocial stress

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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.

Transcriptional activation by the thyroid hormone receptor through ligand-dependent receptor recruitment and chromatin remodelling.

Science.gov (United States)

Grøntved, Lars; Waterfall, Joshua J; Kim, Dong Wook; Baek, Songjoon; Sung, Myong-Hee; Zhao, Li; Park, Jeong Won; Nielsen, Ronni; Walker, Robert L; Zhu, Yuelin J; Meltzer, Paul S; Hager, Gordon L; Cheng, Sheue-yann

2015-04-28

A bimodal switch model is widely used to describe transcriptional regulation by the thyroid hormone receptor (TR). In this model, the unliganded TR forms stable, chromatin-bound complexes with transcriptional co-repressors to repress transcription. Binding of hormone dissociates co-repressors and facilitates recruitment of co-activators to activate transcription. Here we show that in addition to hormone-independent TR occupancy, ChIP-seq against endogenous TR in mouse liver tissue demonstrates considerable hormone-induced TR recruitment to chromatin associated with chromatin remodelling and activated gene transcription. Genome-wide footprinting analysis using DNase-seq provides little evidence for TR footprints both in the absence and presence of hormone, suggesting that unliganded TR engagement with repressive complexes on chromatin is, similar to activating receptor complexes, a highly dynamic process. This dynamic and ligand-dependent interaction with chromatin is likely shared by all steroid hormone receptors regardless of their capacity to repress transcription in the absence of ligand.

Cross-talk between the NR3B and NR4A families of orphan nuclear receptors

International Nuclear Information System (INIS)

Lammi, Johanna; Rajalin, Ann-Marie; Huppunen, Johanna; Aarnisalo, Piia

2007-01-01

Estrogen-related receptors (NR3B family) and Nurr1, NGFI-B, and Nor1 (NR4A family) are orphan nuclear receptors lacking identified natural ligands. The mechanisms regulating their transcriptional activities have remained elusive. We have previously observed that the members of NR3B and NR4A families are coexpressed in certain cell types such as osteoblasts and that the ability of Nurr1 to transactivate the osteopontin promoter is repressed by ERRs. We have now studied the cross-talk between NR3B and NR4A receptors. We show that NR3B and NR4A receptors mutually repress each others' transcriptional activity. The repression involves intact DNA-binding domains and dimerization interfaces but does not result from competition for DNA binding or from heterodimerization. The activation functions of NR3B and NR4A receptors are dispensable for the cross-talk. In conclusion, we report that cross-talk between NR3B and NR4A receptors is a mechanism modulating the transcriptional activities of these orphan nuclear receptors

A Comprehensive Nuclear Receptor Network for Breast Cancer Cells

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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.

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

Antidiabetic actions of a phosphatidylcholine ligand for nuclear receptor LRH-1

Science.gov (United States)

Lee, Jae Man; Lee, Yoon Kwang; Mamrosh, Jennifer L.; Busby, Scott A.; Griffin, Patrick R.; Pathak, Manish C.; Ortlund, Eric A.; Moore, David D.

2011-01-01

Nuclear hormone receptors regulate diverse metabolic pathways and the orphan nuclear receptor LRH-1 (NR5A2) regulates bile acid biosynthesis1,2. Structural studies have identified phospholipids as potential LRH-1 ligands3–5, but their functional relevance is unclear. Here we show that an unusual phosphatidylcholine species with two saturated 12 carbon fatty acid acyl side chains (dilauroyl phosphatidylcholine, DLPC) is an LRH-1 agonist ligand in vitro. DLPC treatment induces bile acid biosynthetic enzymes in mouse liver, increases bile acid levels, and lowers hepatic triglycerides and serum glucose. DLPC treatment also decreases hepatic steatosis and improves glucose homeostasis in two mouse models of insulin resistance. Both the antidiabetic and lipotropic effects are lost in liver specific Lrh-1 knockouts. These findings identify an LRH-1 dependent phosphatidylcholine signaling pathway that regulates bile acid metabolism and glucose homeostasis. PMID:21614002

Structure of a 13-fold superhelix (almost determined from first principles

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Guillaume A. Schoch

2015-03-01

Full Text Available Nuclear hormone receptors are cytoplasm-based transcription factors that bind a ligand, translate to the nucleus and initiate gene transcription in complex with a co-activator such as TIF2 (transcriptional intermediary factor 2. For structural studies the co-activator is usually mimicked by a peptide of circa 13 residues, which for the largest part forms an α-helix when bound to the receptor. The aim was to co-crystallize the glucocorticoid receptor in complex with a ligand and the TIF2 co-activator peptide. The 1.82 Å resolution diffraction data obtained from the crystal could not be phased by molecular replacement using the known receptor structures. HPLC analysis of the crystals revealed the absence of the receptor and indicated that only the co-activator peptide was present. The self-rotation function displayed 13-fold rotational symmetry, which initiated an exhaustive but unsuccessful molecular-replacement approach using motifs of 13-fold symmetry such as α- and β-barrels in various geometries. The structure was ultimately determined by using a single α-helix and the software ARCIMBOLDO, which assembles fragments placed by PHASER before using them as seeds for density modification model building in SHELXE. Systematic variation of the helix length revealed upper and lower size limits for successful structure determination. A beautiful but unanticipated structure was obtained that forms superhelices with left-handed twist throughout the crystal, stabilized by ligand interactions. Together with the increasing diversity of structural elements in the Protein Data Bank the results from TIF2 confirm the potential of fragment-based molecular replacement to significantly accelerate the phasing step for native diffraction data at around 2 Å resolution.

Multi-scale complexity analysis of muscle coactivation during gait in children with cerebral palsy

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Wen eTao

2015-07-01

Full Text Available The objective of this study is to characterize complexity of lower-extremity muscle coactivation and coordination during gait in children with cerebral palsy (CP, children with typical development (TD and healthy adults, by applying recently developed multivariate multi-scale entropy (MMSE analysis to surface EMG signals. Eleven CP children (CP group, eight TD children and seven healthy adults (consider as an entire control group were asked to walk while surface EMG signals were collected from 5 thigh muscles and 3 lower leg muscles on each leg (16 EMG channels in total. The 16-channel surface EMG data, recorded during a series of consecutive gait cycles, were simultaneously processed by multivariate empirical mode decomposition (MEMD, to generate fully aligned data scales for subsequent MMSE analysis. In order to conduct extensive examination of muscle coactivation complexity using the MEMD-enhanced MMSE, 14 data analysis schemes were designed by varying partial muscle combinations and time durations of data segments. Both TD children and healthy adults showed almost consistent MMSE curves over multiple scales for all the 14 schemes, without any significant difference (p > 0.09. However, quite diversity in MMSE curve was observed in the CP group when compared with those in the control group. There appears to be diverse neuropathological processes in CP that may affect dynamical complexity of muscle coactivation and coordination during gait. The abnormal complexity patterns emerging in CP group can be attributed to different factors such as motor control impairments, loss of muscle couplings, and spasticity or paralysis in individual muscles. All these findings expand our knowledge of neuropathology of CP from a novel point of view of muscle co-activation complexity, also indicating the potential to derive a quantitative index for assessing muscle activation characteristics as well as motor function in CP.

The Race that Precedes Coactivation: Development of Multisensory Facilitation in Children

Science.gov (United States)

Barutchu, Ayla; Crewther, David P.; Crewther, Sheila G.

2009-01-01

Rationale: The facilitating effect of multisensory integration on motor responses in adults is much larger than predicted by race-models and is in accordance with the idea of coactivation. However, the development of multisensory facilitation of endogenously driven motor processes and its relationship to the development of complex cognitive skills…

In vitro nuclear receptor inhibition and cytotoxicity of hydraulic fracturing chemicals and their binary mixtures.

Science.gov (United States)

Bain, Peter A; Kumar, Anu

2018-05-01

The widespread use of hydraulic fracturing (HF) in oil and gas extraction operations has led to concern over environmental risks posed by chemicals used in HF fluids. Here we employed a suite of stable luciferase reporter gene assays to investigate the potential for selected HF chemicals or geogenics to activate or antagonise nuclear receptor signalling. We screened three biocides (bronopol [BP], glutaraldehyde [GA], and tetrakis(hydroxymethyl)phosphonium sulfate [THPS]), a surfactant (2-butoxyethanol), a friction reducer (polyacrylamide), and a coal seam geogenic (o-cresol) for their potential to act as agonists or antagonists of the estrogen receptor, androgen receptor, progesterone receptor (PR), glucocorticoid receptor or peroxisome proliferator-activated receptor gamma (PPARγ). None of the chemicals induced luciferase activity in any of assays used in the study. In antagonistic mode, BP, GA and THPS caused reductions in luciferase activity in the reporter assays at higher concentrations (50-100 μM), while at low concentrations (2-10 μM) GA and THPS enhanced luciferase activity in some assays relative to controls. None of the other tested chemicals exhibited antagonism in the selected assays. In most cases, altered receptor signalling only occurred at concentrations exhibiting cytotoxicity. However, PPARγ activity, and to a lesser extent PR activity, were inhibited by THPS at sub-cytotoxic concentrations. The majority of binary combinations tested exhibited significantly less-than-additive cytotoxicity, and none of the combinations exhibited synergistic cytotoxicity. In summary, the results of the present study indicate that the selected chemicals are not likely to function as direct agonists of the nuclear receptors tested, and only one chemical, THPS was an apparent partial antagonist of two nuclear receptors. Copyright © 2017. Published by Elsevier Ltd.

Cloning retinoid and peroxisome proliferator-activated nuclear receptors of the Pacific oyster and in silico binding to environmental chemicals.

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Susanne Vogeler

Full Text Available Disruption of nuclear receptors, a transcription factor superfamily regulating gene expression in animals, is one proposed mechanism through which pollution causes effects in aquatic invertebrates. Environmental pollutants have the ability to interfere with the receptor's functions through direct binding and inducing incorrect signals. Limited knowledge of invertebrate endocrinology and molecular regulatory mechanisms, however, impede the understanding of endocrine disruptive effects in many aquatic invertebrate species. Here, we isolated three nuclear receptors of the Pacific oyster, Crassostrea gigas: two isoforms of the retinoid X receptor, CgRXR-1 and CgRXR-2, a retinoic acid receptor ortholog CgRAR, and a peroxisome proliferator-activated receptor ortholog CgPPAR. Computer modelling of the receptors based on 3D crystal structures of human proteins was used to predict each receptor's ability to bind to different ligands in silico. CgRXR showed high potential to bind and be activated by 9-cis retinoic acid and the organotin tributyltin (TBT. Computer modelling of CgRAR revealed six residues in the ligand binding domain, which prevent the successful interaction with natural and synthetic retinoid ligands. This supports an existing theory of loss of retinoid binding in molluscan RARs. Modelling of CgPPAR was less reliable due to high discrepancies in sequence to its human ortholog. Yet, there are suggestions of binding to TBT, but not to rosiglitazone. The effect of potential receptor ligands on early oyster development was assessed after 24h of chemical exposure. TBT oxide (0.2μg/l, all-trans retinoic acid (ATRA (0.06 mg/L and perfluorooctanoic acid (20 mg/L showed high effects on development (>74% abnormal developed D-shelled larvae, while rosiglitazone (40 mg/L showed no effect. The results are discussed in relation to a putative direct (TBT disruption effect on nuclear receptors. The inability of direct binding of ATRA to CgRAR suggests

The PDZ-binding motif of Yes-associated protein is required for its co-activation of TEAD-mediated CTGF transcription and oncogenic cell transforming activity

International Nuclear Information System (INIS)

Shimomura, Tadanori; Miyamura, Norio; Hata, Shoji; Miura, Ryota; Hirayama, Jun; Nishina, Hiroshi

2014-01-01

Highlights: •Loss of the PDZ-binding motif inhibits constitutively active YAP (5SA)-induced oncogenic cell transformation. •The PDZ-binding motif of YAP promotes its nuclear localization in cultured cells and mouse liver. •Loss of the PDZ-binding motif inhibits YAP (5SA)-induced CTGF transcription in cultured cells and mouse liver. -- Abstract: YAP is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes, including proliferation. Hippo pathway-dependent phosphorylation of YAP negatively regulates its function. Conversely, attenuation of Hippo-mediated phosphorylation of YAP increases its ability to stimulate proliferation and eventually induces oncogenic transformation. The C-terminus of YAP contains a highly conserved PDZ-binding motif that regulates YAP’s functions in multiple ways. However, to date, the importance of the PDZ-binding motif to the oncogenic cell transforming activity of YAP has not been determined. In this study, we disrupted the PDZ-binding motif in the YAP (5SA) protein, in which the sites normally targeted by Hippo pathway-dependent phosphorylation are mutated. We found that loss of the PDZ-binding motif significantly inhibited the oncogenic transformation of cultured cells induced by YAP (5SA). In addition, the increased nuclear localization of YAP (5SA) and its enhanced activation of TEAD-dependent transcription of the cell proliferation gene CTGF were strongly reduced when the PDZ-binding motif was deleted. Similarly, in mouse liver, deletion of the PDZ-binding motif suppressed nuclear localization of YAP (5SA) and YAP (5SA)-induced CTGF expression. Taken together, our results indicate that the PDZ-binding motif of YAP is critical for YAP-mediated oncogenesis, and that this effect is mediated by YAP’s co-activation of TEAD-mediated CTGF transcription

The PDZ-binding motif of Yes-associated protein is required for its co-activation of TEAD-mediated CTGF transcription and oncogenic cell transforming activity

Energy Technology Data Exchange (ETDEWEB)

Shimomura, Tadanori; Miyamura, Norio; Hata, Shoji; Miura, Ryota; Hirayama, Jun, E-mail: hirayama.dbio@mri.tmd.ac.jp; Nishina, Hiroshi, E-mail: nishina.dbio@mri.tmd.ac.jp

2014-01-17

Highlights: •Loss of the PDZ-binding motif inhibits constitutively active YAP (5SA)-induced oncogenic cell transformation. •The PDZ-binding motif of YAP promotes its nuclear localization in cultured cells and mouse liver. •Loss of the PDZ-binding motif inhibits YAP (5SA)-induced CTGF transcription in cultured cells and mouse liver. -- Abstract: YAP is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes, including proliferation. Hippo pathway-dependent phosphorylation of YAP negatively regulates its function. Conversely, attenuation of Hippo-mediated phosphorylation of YAP increases its ability to stimulate proliferation and eventually induces oncogenic transformation. The C-terminus of YAP contains a highly conserved PDZ-binding motif that regulates YAP’s functions in multiple ways. However, to date, the importance of the PDZ-binding motif to the oncogenic cell transforming activity of YAP has not been determined. In this study, we disrupted the PDZ-binding motif in the YAP (5SA) protein, in which the sites normally targeted by Hippo pathway-dependent phosphorylation are mutated. We found that loss of the PDZ-binding motif significantly inhibited the oncogenic transformation of cultured cells induced by YAP (5SA). In addition, the increased nuclear localization of YAP (5SA) and its enhanced activation of TEAD-dependent transcription of the cell proliferation gene CTGF were strongly reduced when the PDZ-binding motif was deleted. Similarly, in mouse liver, deletion of the PDZ-binding motif suppressed nuclear localization of YAP (5SA) and YAP (5SA)-induced CTGF expression. Taken together, our results indicate that the PDZ-binding motif of YAP is critical for YAP-mediated oncogenesis, and that this effect is mediated by YAP’s co-activation of TEAD-mediated CTGF transcription.

SRC-2 is an essential coactivator for orchastrating metabolism and circadian rhythm

Science.gov (United States)

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:C...

Effects of different ligands on epidermal growth factor receptor (EGFR) nuclear translocation

International Nuclear Information System (INIS)

Faria, Jerusa A.Q.A.; Andrade, Carolina de; Goes, Alfredo M.; Rodrigues, Michele A.; Gomes, Dawidson A.

2016-01-01

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.

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.

Characterization of germ cell-specific expression of the orphan nuclear receptor, germ cell nuclear factor.

Science.gov (United States)

Katz, D; Niederberger, C; Slaughter, G R; Cooney, A J

1997-10-01

Nuclear receptors, such as those for androgens, estrogens, and progesterones, control many reproductive processes. Proteins with structures similar to these receptors, but for which ligands have not yet been identified, have been termed orphan nuclear receptors. One of these orphans, germ cell nuclear factor (GCNF), has been shown to be germ cell specific in the adult and, therefore, may also participate in the regulation of reproductive functions. In this paper, we examine more closely the expression patterns of GCNF in germ cells to begin to define spatio-temporal domains of its activity. In situ hybridization showed that GCNF messenger RNA (mRNA) is lacking in the testis of hypogonadal mutant mice, which lack developed spermatids, but is present in the wild-type testis. Thus, GCNF is, indeed, germ cell specific in the adult male. Quantitation of the specific in situ hybridization signal in wild-type testis reveals that GCNF mRNA is most abundant in stage VII round spermatids. Similarly, Northern analysis and specific in situ hybridization show that GCNF expression first occurs in testis of 20-day-old mice, when round spermatids first emerge. Therefore, in the male, GCNF expression occurs postmeiotically and may participate in the morphological changes of the maturing spermatids. In contrast, female expression of GCNF is shown in growing oocytes that have not completed the first meiotic division. Thus, GCNF in the female is expressed before the completion of meiosis. Finally, the nature of the two different mRNAs that hybridize to the GCNF complementary DNA was studied. Although both messages contain the DNA binding domain, only the larger message is recognized by a probe from the extreme 3' untranslated region. In situ hybridization with these differential probes demonstrates that both messages are present in growing oocytes. In addition, the coding region and portions of the 3' untranslated region of the GCNF complementary DNA are conserved in the rat.

The metabolic activator FOXO1 binds hepatitis B virus DNA and activates its transcription

International Nuclear Information System (INIS)

Shlomai, Amir; Shaul, Yosef

2009-01-01

Hepatitis B virus (HBV) is a small DNA virus that targets the liver and infects humans worldwide. Recently we have shown that the metabolic regulator PGC-1α coactivates HBV transcription thereby rendering the virus susceptible to fluctuations in the nutritional status of the liver. PGC-1α coactivation of HBV is mediated through the liver-enriched nuclear receptor HNF4α and through another yet unknown transcription factor(s). Here we show that the forkhead transcription factor FOXO1, a known target for PGC-1α coactivation and a central mediator of glucose metabolism in the liver, binds HBV core promoter and activates its transcription. This activation is further enhanced in the presence of PGC-1α, implying that FOXO1 is a target for PGC-1α coactivation of HBV transcription. Thus, our results identify another key metabolic regulator as an activator of HBV transcription, thereby supporting the principle that HBV gene expression is regulated in a similar way to key hepatic metabolic genes.

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,

Sertad1 encodes a novel transcriptional co-activator of SMAD1 in mouse embryonic hearts

Energy Technology Data Exchange (ETDEWEB)

Peng, Yin [Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Zhao, Shaomin [Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294 (United States); School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069 (China); Song, Langying [Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Wang, Manyuan [School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069 (China); Jiao, Kai, E-mail: kjiao@uab.edu [Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294 (United States)

2013-11-29

Highlights: •SERTAD1 interacts with SMAD1. •Sertad1 is expressed in mouse embryonic hearts. •SERTAD1 is localized in both cytoplasm and nucleus of cardiomyocytes. •SERTAD1 enhances expression of BMP target cardiogenic genes as a SMAD1 co-activator. -- Abstract: Despite considerable advances in surgical repairing procedures, congenital heart diseases (CHDs) remain the leading noninfectious cause of infant morbidity and mortality. Understanding the molecular/genetic mechanisms underlying normal cardiogenesis will provide essential information for the development of novel diagnostic and therapeutic strategies against CHDs. BMP signaling plays complex roles in multiple cardiogenic processes in mammals. SMAD1 is a canonical nuclear mediator of BMP signaling, the activity of which is critically regulated through its interaction partners. We screened a mouse embryonic heart yeast two-hybrid library using Smad1 as bait and identified SERTAD1 as a novel interaction partner of SMAD1. SERTAD1 contains multiple potential functional domains, including two partially overlapping transactivation domains at the C terminus. The SERTAD1-SMAD1 interaction in vitro and in mammalian cells was further confirmed through biochemical assays. The expression of Sertad1 in developing hearts was demonstrated using RT-PCR, western blotting and in situ hybridization analyses. We also showed that SERTAD1 was localized in both the cytoplasm and nucleus of immortalized cardiomyocytes and primary embryonic cardiomyocyte cultures. The overexpression of SERTAD1 in cardiomyocytes not only enhanced the activity of two BMP reporters in a dose-dependent manner but also increased the expression of several known BMP/SMAD regulatory targets. Therefore, these data suggest that SERTAD1 acts as a SMAD1 transcriptional co-activator to promote the expression of BMP target genes during mouse cardiogenesis.

Hamstrings co-activation in ACL-deficient subjects during isometric whole-leg extensions

NARCIS (Netherlands)

Aalbersberg, S.; Kingma, I.; van Dieen, J.H.

2009-01-01

It has been reported that anterior cruciate ligament (ACL)-deficient subjects increase the level of hamstrings activation and this has been interpreted as a means to cope with increased anterior tibial laxity in the knee. This study aimed to establish to what extent co-activation strategies in

Estrogen promotes megakaryocyte polyploidization via estrogen receptor beta-mediated transcription of GATA1.

Science.gov (United States)

Du, C; Xu, Y; Yang, K; Chen, S; Wang, X; Wang, S; Wang, C; Shen, M; Chen, F; Chen, M; Zeng, D; Li, F; Wang, T; Wang, F; Zhao, J; Ai, G; Cheng, T; Su, Y; Wang, J

2017-04-01

Estrogen is reported to be involved in thrombopoiesis and the disruption of its signaling may cause myeloproliferative disease, yet the underlying mechanisms remain largely unknown. GATA-binding factor 1 (GATA1) is a key regulator of megakaryocyte (MK) differentiation and its deficiency will lead to megakaryoblastic leukemia. Here we show that estrogen can dose-dependently promote MK polyploidization and maturation via activation of estrogen receptor beta (ERβ), accompanied by a significant upregulation of GATA1. Chromatin immunoprecipitation and a dual luciferase assay demonstrate that ERβ can directly bind the promoter region of GATA1 and activate its transcription. Steroid receptor coactivator 3 (SRC3) is involved in ERβ-mediated GATA1 transcription. The deficiency of ERβ or SRC3, similar to the inhibition of GATA1, leads to the impediment of estrogen-induced MK polyploidization and platelet production. Further investigations reveal that signal transducer and activator of transcription 1 signaling pathway downstream of GATA1 has a crucial role in estrogen-induced MK polyploidization, and ERβ-mediated GATA1 upregulation subsequently enhances nuclear factor erythroid-derived 2 expression, thereby promoting proplatelet formation and platelet release. Our study provides a deep insight into the molecular mechanisms of estrogen signaling in regulating thrombopoiesis and the pathogenesis of ER deficiency-related leukemia.

AKT3 controls mitochondrial biogenesis and autophagy via regulation of the major nuclear export protein CRM-1.

Science.gov (United States)

Corum, Daniel G; Tsichlis, Philip N; Muise-Helmericks, Robin C

2014-01-01

Our previous work has shown that Akt3 is required for mitochondrial biogenesis in primary human endothelial cells (ECs) and in Akt3-null mice; Akt3 affects subcellular localization of peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α), the master regulator of mitochondrial biogenesis. The purpose of this study is to determine the mechanism by which Akt3 controls the subcellular distribution of PGC-1α and to explore the effect on mitochondrial biogenesis and turnover during angiogenesis. Here we use standard biochemical analyses and Akt3-knockdown strategies to show that Akt3 controls the stabilization of chromosome maintenance region-1 (CRM-1), the major nuclear export receptor. Site-directed mutagenesis and association analyses show that PGC-1α nuclear export is CRM-1 dependent. Akt3 knockdown and CRM-1 overexpression cause 3-fold reductions in PGC-1α target gene expression, compared to control levels. Akt3 inhibition causes autophagy, as measured by autophagosome formation, in a CRM-1-dependent, Akt1/mTOR-independent pathway. In vivo, Akt3-null and heterozygous mice show dose-dependent decreases in angiogenesis compared to wild-type littermates (~5- and 2.5-fold decreases, respectively), as assessed by Matrigel plug assays. This correlates with an ~1.5-fold decrease in mitochondrial Cox IV expression. Our studies suggest that Akt3 is a regulator of mitochondrial dynamics in the vasculature via regulation of CRM-1-dependent nuclear export.

Statin-activated nuclear receptor PXR promotes SGK2 dephosphorylation by scaffolding PP2C to induce hepatic gluconeogenesis.

Science.gov (United States)

Gotoh, Saki; Negishi, Masahiko

2015-09-22

Statin therapy is known to increase blood glucose levels in humans. Statins utilize pregnane X receptor (PXR) and serum/glucocorticoid regulated kinase 2 (SGK2) to activate phosphoenolpyruvate carboxykinase 1 (PEPCK1) and glucose-6-phosphatase (G6Pase) genes, thereby increasing glucose production in human liver cells. Here, the novel statin/PXR/SGK2-mediated signaling pathway has now been characterized for hepatic gluconeogenesis. Statin-activated PXR scaffolds the protein phosphatase 2C (PP2C) and SGK2 to stimulate PP2C to dephosphorylate SGK2 at threonine 193. Non-phosphorylated SGK2 co-activates PXR-mediated trans-activation of promoters of gluconeogenic genes in human liver cells, thereby enhancing gluconeogenesis. This gluconeogenic statin-PXR-SGK2 signal is not present in mice, in which statin treatment suppresses hepatic gluconeogenesis. These findings provide the basis for statin-associated side effects such as an increased risk for Type 2 diabetes.

MED1 independent activation of endogenous target genes by PPARα

DEFF Research Database (Denmark)

Grøntved, Lars; Bugge, Anne K.; Roeder, Robert G.

The mediator complex serves as a transcriptional co-activator complex by acting as a bridge between promoter-bound transcription factors and the preinitiation complex. Genetic and biochemical studies indicate that nuclear receptors recruit the mediator complex through direct interaction with the ......The mediator complex serves as a transcriptional co-activator complex by acting as a bridge between promoter-bound transcription factors and the preinitiation complex. Genetic and biochemical studies indicate that nuclear receptors recruit the mediator complex through direct interaction...... derived from TRAP220 KO mice. Interestingly, rescue experiments in confluent TRAP220 KO MEFs with different versions of MED1 indicate that the LXXLL motif is not necessary for PPARgamma mediated gene activation (Ge et al, MCB published online ahead of print 2007). By analogy, we show here that MED1...... is dispensable for PPARalpha transcriptional activity in proliferating but is necessary in confluent AML-12 cells and TRAP220 KO MEFs. Collectively this indicates that the PPARs might have adopted an alternative mediator recruitment mechanism that is dispensable of direct interaction with MED1 on endogenous...

Inhibition of Androgen Receptor Nuclear Localization and Castration-Resistant Prostate Tumor Growth by Pyrroloimidazole-based Small Molecules.

Science.gov (United States)

Masoodi, Khalid Z; Xu, Yadong; Dar, Javid A; Eisermann, Kurtis; Pascal, Laura E; Parrinello, Erica; Ai, Junkui; Johnston, Paul A; Nelson, Joel B; Wipf, Peter; Wang, Zhou

2017-10-01

The androgen receptor (AR) is a ligand-dependent transcription factor that controls the expression of androgen-responsive genes. A key step in androgen action, which is amplified in castration-resistant prostate cancer (CRPC), is AR nuclear translocation. Small molecules capable of inhibiting AR nuclear localization could be developed as novel therapeutics for CRPC. We developed a high-throughput screen and identified two structurally-related pyrroloimidazoles that could block AR nuclear localization in CRPC cells. We show that these two small molecules, 3-(4-ethoxyphenyl)-6,7-dihydro-5 H -pyrrolo[1,2- a ]imidazole (EPPI) and 3-(4-chlorophenyl)-6,7-dihydro-5 H -pyrrolo[1,2- a ]imidazole (CPPI) can inhibit the nuclear localization and transcriptional activity of AR and reduce the proliferation of AR-positive but not AR-negative prostate cancer cell lines. EPPI and CPPI did not inhibit nuclear localization of the glucocorticoid receptor or the estrogen receptor, suggesting they selectively target AR. In LNCaP tumor xenografts, CPPI inhibited the proliferation of relapsed LNCaP tumors. These findings suggest that EPPI and CPPI could serve as lead structures for the development of therapeutic agents for CRPC. Mol Cancer Ther; 16(10); 2120-9. ©2017 AACR . ©2017 American Association for Cancer Research.

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

DNA homologous recombination factor SFR1 physically and functionally interacts with estrogen receptor alpha.

Directory of Open Access Journals (Sweden)

Yuxin Feng

Full Text Available Estrogen receptor alpha (ERα, a ligand-dependent transcription factor, mediates the expression of its target genes by interacting with corepressors and coactivators. Since the first cloning of SRC1, more than 280 nuclear receptor cofactors have been identified, which orchestrate target gene transcription. Aberrant activity of ER or its accessory proteins results in a number of diseases including breast cancer. Here we identified SFR1, a protein involved in DNA homologous recombination, as a novel binding partner of ERα. Initially isolated in a yeast two-hybrid screen, the interaction of SFR1 and ERα was confirmed in vivo by immunoprecipitation and mammalian one-hybrid assays. SFR1 co-localized with ERα in the nucleus, potentiated ER's ligand-dependent and ligand-independent transcriptional activity, and occupied the ER binding sites of its target gene promoters. Knockdown of SFR1 diminished ER's transcriptional activity. Manipulating SFR1 expression by knockdown and overexpression revealed a role for SFR1 in ER-dependent and -independent cancer cell proliferation. SFR1 differs from SRC1 by the lack of an intrinsic activation function. Taken together, we propose that SFR1 is a novel transcriptional modulator for ERα and a potential target in breast cancer therapy.

Androgen receptor regulates nuclear trafficking and nuclear domain residency of corepressor HDAC7 in a ligand-dependent fashion

International Nuclear Information System (INIS)

Karvonen, Ulla; Jaenne, Olli A.; Palvimo, Jorma J.

2006-01-01

In addition to chromosomal proteins, histone deacetylases (HDACs) target transcription factors in transcriptional repression. Here, we show that the class II HDAC family member HDAC7 is an efficient corepressor of the androgen receptor (AR). HDAC7 resided in the cytoplasm in the absence of AR or a cognate ligand, but hormone-occupancy of AR induced nuclear transfer of HDAC7. Nuclear colocalization pattern of AR and HDAC7 was dependent on the nature of the ligand. In the presence of testosterone, a portion of HDAC7 localized to pearl-like nuclear domains, whereas AR occupied with antagonistic ligands cyproterone acetate- or casodex (bicalutamide) recruited HDAC7 from these domains to colocalize with the receptor in speckles and nucleoplasm in a more complete fashion. Ectopic expression of PML-3 relieved the repressive effect of HDAC7 on AR function by sequestering HDAC7 to PML-3 domains. AR acetylation at Lys630/632/633 was not the target of HDAC7 repression, since repression of AR function was independent of these acetylation sites. Moreover, the deacetylase activity of HDAC7 was in part dispensable in the repression of AR function. In sum, our results identify HDAC7 as a novel AR corepressor whose subcellular and subnuclear compartmentalization can be regulated in an androgen-selective manner

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.…

Cell-Type-Specific Regulation of the Retinoic Acid Receptor Mediated by the Orphan Nuclear Receptor TLX†

Science.gov (United States)

Kobayashi, Mime; Yu, Ruth T.; Yasuda, Kunio; Umesono, Kazuhiko

2000-01-01

Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor β (RARβ). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARβ2 promoter. The region surrounding the transcription start site of the avian RARβ2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARβ2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARβ gene in the eye. PMID:11073974

Cell-type-specific regulation of the retinoic acid receptor mediated by the orphan nuclear receptor TLX.

Science.gov (United States)

Kobayashi, M; Yu, R T; Yasuda, K; Umesono, K

2000-12-01

Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor beta (RARbeta). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARbeta2 promoter. The region surrounding the transcription start site of the avian RARbeta2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARbeta2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARbeta gene in the eye.

Multiplicity of nuclear receptor activation by PFOA and PFOS in primary human and rodent hepatocytes

International Nuclear Information System (INIS)

Bjork, J.A.; Butenhoff, J.L.; Wallace, K.B.

2011-01-01

Perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) are surface active fluorochemicals that, due to their exceptional stability to degradation, are persistent in the environment. Both PFOA and PFOS are eliminated slowly in humans, with geometric mean serum elimination half-lives estimated at 3.5 and 4.8 years, respectively. The biological activity of PFOA and PFOS in rodents is attributed primarily to transactivation of the nuclear receptor peroxisome proliferator activated receptor alpha (PPARA), which is an important regulator of lipid and carbohydrate metabolism. However, there are significant species-specific differences in the response to PFOA and PFOS exposure; non-rodent species, including humans, are refractory to several but not all of these effects. Many of the metabolic effects have been attributed to the activation of PPARA; however, recent studies using PPARα knockout mice demonstrate residual PPARA-independent effects, some of which may involve the activation of alternate nuclear receptors, including NR1I2 (PXR), NR1I3 (CAR), NR1H3 (LXRA), and NR1H4 (FXR). The objective of this investigation was to characterize the activation of multiple nuclear receptors and modulation of metabolic pathways associated with exposure to PFOA and PFOS, and to compare and contrast the effects between rat and human primary liver cells using quantitative reverse transcription PCR (RT-qPCR). Our results demonstrate that multiple nuclear receptors participate in the metabolic response to PFOA and PFOS exposure resulting in a substantial shift from carbohydrate metabolism to fatty acid oxidation and hepatic triglyceride accumulation in rat liver cells. This shift in intermediary metabolism was more pronounced for PFOA than PFOS. Furthermore, while there is some similarity in the activation of metabolic pathways between rat and humans, particularly in PPARA regulated responses; the changes in primary human cells were more subtle and possibly reflect an adaptive

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.

The nuclear localization of low risk HPV11 E7 protein mediated by its zinc binding domain is independent of nuclear import receptors

International Nuclear Information System (INIS)

Piccioli, Zachary; McKee, Courtney H.; Leszczynski, Anna; Onder, Zeynep; Hannah, Erin C.; Mamoor, Shahan; Crosby, Lauren; Moroianu, Junona

2010-01-01

We investigated the nuclear import of low risk HPV11 E7 protein using 1) transfection assays in HeLa cells with EGFP fusion plasmids containing 11E7 and its domains and 2) nuclear import assays in digitonin-permeabilized HeLa cells with GST fusion proteins containing 11E7 and its domains. The EGFP-11E7 and EGFP-11cE7 39-98 localized mostly to the nucleus. The GST-11E7 and GST-11cE7 39-98 were imported into the nuclei in the presence of either Ran-GDP or RanG19V-GTP mutant and in the absence of nuclear import receptors. This suggests that 11E7 enters the nucleus via a Ran-dependent pathway, independent of nuclear import receptors, mediated by a nuclear localization signal located in its C-terminal domain (cNLS). This cNLS contains the zinc binding domain consisting of two copies of Cys-X-X-Cys motif. Mutagenesis of Cys residues in these motifs changed the localization of the EGFP-11cE7/-11E7 mutants to cytoplasmic, suggesting that the zinc binding domain is essential for nuclear localization of 11E7.

Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

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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.

Listening to Puns Elicits the Co-Activation of Alternative Homophone Meanings during Language Production.

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Sebastian Benjamin Rose

Full Text Available Recent evidence suggests that lexical-semantic activation spread during language production can be dynamically shaped by contextual factors. In this study we investigated whether semantic processing modes can also affect lexical-semantic activation during word production. Specifically, we tested whether the processing of linguistic ambiguities, presented in the form of puns, has an influence on the co-activation of unrelated meanings of homophones in a subsequent language production task. In a picture-word interference paradigm with word distractors that were semantically related or unrelated to the non-depicted meanings of homophones we found facilitation induced by related words only when participants listened to puns before object naming, but not when they heard jokes with unambiguous linguistic stimuli. This finding suggests that a semantic processing mode of ambiguity perception can induce the co-activation of alternative homophone meanings during speech planning.

A protein interaction atlas for the nuclear receptors: properties and quality of a hub-based dimerisation network

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De Graaf David

2007-07-01

Full Text Available Abstract Background The nuclear receptors are a large family of eukaryotic transcription factors that constitute major pharmacological targets. They exert their combinatorial control through homotypic heterodimerisation. Elucidation of this dimerisation network is vital in order to understand the complex dynamics and potential cross-talk involved. Results Phylogeny, protein-protein interactions, protein-DNA interactions and gene expression data have been integrated to provide a comprehensive and up-to-date description of the topology and properties of the nuclear receptor interaction network in humans. We discriminate between DNA-binding and non-DNA-binding dimers, and provide a comprehensive interaction map, that identifies potential cross-talk between the various pathways of nuclear receptors. Conclusion We infer that the topology of this network is hub-based, and much more connected than previously thought. The hub-based topology of the network and the wide tissue expression pattern of NRs create a highly competitive environment for the common heterodimerising partners. Furthermore, a significant number of negative feedback loops is present, with the hub protein SHP [NR0B2] playing a major role. We also compare the evolution, topology and properties of the nuclear receptor network with the hub-based dimerisation network of the bHLH transcription factors in order to identify both unique themes and ubiquitous properties in gene regulation. In terms of methodology, we conclude that such a comprehensive picture can only be assembled by semi-automated text-mining, manual curation and integration of data from various sources.

CITED2 modulates estrogen receptor transcriptional activity in breast cancer cells

International Nuclear Information System (INIS)

Lau, Wen Min; Doucet, Michele; Huang, David; Weber, Kristy L.; Kominsky, Scott L.

2013-01-01

Highlights: •The effects of elevated CITED2 on ER function in breast cancer cells are examined. •CITED2 enhances cell growth in the absence of estrogen and presence of tamoxifen. •CITED2 functions as a transcriptional co-activator of ER in breast cancer cells. -- Abstract: Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2) is a member of the CITED family of non-DNA binding transcriptional co-activators of the p300/CBP-mediated transcription complex. Previously, we identified CITED2 as being overexpressed in human breast tumors relative to normal mammary epithelium. Upon further investigation within the estrogen receptor (ER)-positive subset of these breast tumor samples, we found that CITED2 mRNA expression was elevated in those associated with poor survival. In light of this observation, we investigated the effect of elevated CITED2 levels on ER function. While ectopic overexpression of CITED2 in three ER-positive breast cancer cell lines (MCF-7, T47D, and CAMA-1) did not alter cell proliferation in complete media, growth was markedly enhanced in the absence of exogenous estrogen. Correspondingly, cells overexpressing CITED2 demonstrated reduced sensitivity to the growth inhibitory effects of the selective estrogen receptor modulator, 4-hydroxytamoxifen. Subsequent studies revealed that basal ER transcriptional activity was elevated in CITED2-overexpressing cells and was further increased upon the addition of estrogen. Similarly, basal and estrogen-induced expression of the ER-regulated genes trefoil factor 1 (TFF1) and progesterone receptor (PGR) was higher in cells overexpressing CITED2. Concordant with this observation, ChIP analysis revealed higher basal levels of CITED2 localized to the TFF-1 and PGR promoters in cells with ectopic overexpression of CITED2, and these levels were elevated further in response to estrogen stimulation. Taken together, these data indicate that CITED2 functions as a transcriptional co-activator

Implicit co-activation of American Sign Language in deaf readers: An ERP study.

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Meade, Gabriela; Midgley, Katherine J; Sevcikova Sehyr, Zed; Holcomb, Phillip J; Emmorey, Karen

2017-07-01

In an implicit phonological priming paradigm, deaf bimodal bilinguals made semantic relatedness decisions for pairs of English words. Half of the semantically unrelated pairs had phonologically related translations in American Sign Language (ASL). As in previous studies with unimodal bilinguals, targets in pairs with phonologically related translations elicited smaller negativities than targets in pairs with phonologically unrelated translations within the N400 window. This suggests that the same lexicosemantic mechanism underlies implicit co-activation of a non-target language, irrespective of language modality. In contrast to unimodal bilingual studies that find no behavioral effects, we observed phonological interference, indicating that bimodal bilinguals may not suppress the non-target language as robustly. Further, there was a subset of bilinguals who were aware of the ASL manipulation (determined by debrief), and they exhibited an effect of ASL phonology in a later time window (700-900ms). Overall, these results indicate modality-independent language co-activation that persists longer for bimodal bilinguals. Copyright © 2017 Elsevier Inc. All rights reserved.

Nuclear receptor 4A (NR4A) family - orphans no more.

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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.

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

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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.

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

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Van Gilst, Marc R; Hadjivassiliou, Haralambos; Jolly, Amber; Yamamoto, Keith R

2005-02-01

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.

rigor mortis encodes a novel nuclear receptor interacting protein required for ecdysone signaling during Drosophila larval development.

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Gates, Julie; Lam, Geanette; Ortiz, José A; Losson, Régine; Thummel, Carl S

2004-01-01

Pulses of the steroid hormone ecdysone trigger the major developmental transitions in Drosophila, including molting and puparium formation. The ecdysone signal is transduced by the EcR/USP nuclear receptor heterodimer that binds to specific response elements in the genome and directly regulates target gene transcription. We describe a novel nuclear receptor interacting protein encoded by rigor mortis (rig) that is required for ecdysone responses during larval development. rig mutants display defects in molting, delayed larval development, larval lethality, duplicated mouth parts, and defects in puparium formation--phenotypes that resemble those seen in EcR, usp, E75A and betaFTZ-F1 mutants. Although the expression of these nuclear receptor genes is essentially normal in rig mutant larvae, the ecdysone-triggered switch in E74 isoform expression is defective. rig encodes a protein with multiple WD-40 repeats and an LXXLL motif, sequences that act as specific protein-protein interaction domains. Consistent with the presence of these elements and the lethal phenotypes of rig mutants, Rig protein interacts with several Drosophila nuclear receptors in GST pull-down experiments, including EcR, USP, DHR3, SVP and betaFTZ-F1. The ligand binding domain of betaFTZ-F1 is sufficient for this interaction, which can occur in an AF-2-independent manner. Antibody stains reveal that Rig protein is present in the brain and imaginal discs of second and third instar larvae, where it is restricted to the cytoplasm. In larval salivary gland and midgut cells, however, Rig shuttles between the cytoplasm and nucleus in a spatially and temporally regulated manner, at times that correlate with the major lethal phase of rig mutants and major switches in ecdysone-regulated gene expression. Taken together, these data indicate that rig exerts essential functions during larval development through gene-specific effects on ecdysone-regulated transcription, most likely as a cofactor for one or more

Synergistic regulation of the mouse orphan nuclear receptor SHP gene promoter by CLOCK-BMAL1 and LRH-1

International Nuclear Information System (INIS)

Oiwa, Ako; Kakizawa, Tomoko; Miyamoto, Takahide; Yamashita, Koh; Jiang, Wei; Takeda, Teiji; Suzuki, Satoru; Hashizume, Kiyoshi

2007-01-01

Small heterodimer partner (SHP; NR0B2) is an orphan nuclear receptor and acts as a repressor for wide variety of nuclear hormone receptors. We demonstrated here that mouse SHP mRNA showed a circadian expression pattern in the liver. Transient transfection of the mSHP promoter demonstrated that CLOCK-BMAL1, core circadian clock components, bound to E-box (CACGTG), and stimulated the promoter activity by 4-fold. Liver receptor homologue-1 (LRH-1; NR5A2) stimulated the mSHP promoter, and CLOCK-BMAL1 synergistically enhanced the LRH-1-mediated transactivation. Interestingly, SHP did not affect the CLOCK-BMAL1-mediated promoter activity, but strongly repressed the synergistic activation of CLOCK-BMAL1 and LRH-1. Furthermore, in vitro pull-down assays revealed the existence of direct protein-protein interaction between LRH-1 and CLOCK. In summary, this study shows that CLOCK-BMAL1, LRH-1 and SHP coordinately regulate the mSHP gene to generate the circadian oscillation. The cyclic expression of mSHP may affect daily activity of other nuclear receptors and contribute to circadian liver functions

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

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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.

Annotation of the Nuclear Receptors in an Estuarine Fish species, Fundulus heteroclitus

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William S. Baldwin

2017-06-01

Full Text Available The nuclear receptors (NRs are ligand-dependent transcription factors that respond to various internal as well as external cues such as nutrients, pheromones, and steroid hormones that play crucial roles in regulation and maintenance of homeostasis and orchestrating the physiological and stress responses of an organism. We annotated the Fundulus heteroclitus (mummichog; Atlantic killifish nuclear receptors. Mummichog are a non-migratory, estuarine fish with a limited home range often used in environmental research as a field model for studying ecological and evolutionary responses to variable environmental conditions such as salinity, oxygen, temperature, pH, and toxic compounds because of their hardiness. F. heteroclitus have at least 74 NRs spanning all seven gene subfamilies. F. heteroclitus is unique in that no RXRα member was found within the genome. Interestingly, some of the NRs are highly conserved between species, while others show a higher degree of divergence such as PXR, SF1, and ARα. Fundulus like other fish species show expansion of the RAR (NR1B, Rev-erb (NR1D, ROR (NR1F, COUPTF (NR2F, ERR (NR3B, RXR (NR2B, and to a lesser extent the NGF (NR4A, and NR3C steroid receptors (GR/AR. Of particular interest is the co-expansion of opposing NRs, Reverb-ROR, and RAR/RXR-COUPTF.

Control of gene expression and mitochondrial biogenesis in the muscular adaption to endurance exercise

DEFF Research Database (Denmark)

Joseph, A. M.; Pilegaard, H.; Leick, L.

2006-01-01

of these adaptations is an increase in mitochondrial content, which confers a greater resistance to muscle fatigue. This essay reviews current knowledge on the regulation of exercise-induced mitochondrial biogenesis at the molecular level. The major steps involved include, (i) transcriptional regulation of nuclear......-encoded genes encoding mitochondrial proteins by the coactivator peroxisome-proliferatoractivated receptor coactivator-1, (ii) control of mitochondrial DNA gene 1To whom correspondence should be addressed (email dhood@yorku.ca). 13 © 2006 The Biochemical Society Ch-02_essbiochem_hood.indd Page 13 11/13/06 10......:27:15 PM elhi /Volumes/ju108/POIN001/essbiochem_indd%0/Chapter 2 © 2006 The Biochemical Society 14 Essays in Biochemistry volume 42 2006 expression by the transcription factor Tfam, (iii) mitochondrial fi ssion and fusion mechanisms, and (iv) import of nuclear-derived gene products into the mitochondrion...

Atropisomers of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) exhibit stereoselective effects on activation of nuclear receptors in vitro.

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Pěnčíková, Kateřina; Brenerová, Petra; Svržková, Lucie; Hrubá, Eva; Pálková, Lenka; Vondráček, Jan; Lehmler, Hans-Joachim; Machala, Miroslav

2017-11-09

PCB 136 is an environmentally relevant chiral PCB congener, which has been found in vivo to be present in form of rotational isomers (atropisomers). Its atropselective biotransformation or neurotoxic effects linked with sensitization of ryanodine receptor suggest that it might interact also with other intracellular receptors in a stereospecific manner. However, possible atropselective effects of PCB 136 on nuclear receptor transactivation remain unknown. Therefore, in this study, atropselective effects of PCB 136 on nuclear receptors controlling endocrine signaling and/or expression of xenobiotic and steroid hormone catabolism were investigated. PCB136 atropisomers were found to exert differential effects on estrogen receptor (ER) activation; (+)-PCB 136 was estrogenic, while (-)-PCB 136 was antiestrogenic. In contrast, inhibition of androgen receptor (AR) activity was not stereospecific. Both PCB136 stereoisomers induced the constitutive androgen receptor (CAR)-dependent gene expression; however, no significant stereospecificity of PCB 136 atropisomers was observed. PCB136 was a partial inducer of the pregnane X receptor (PXR)-dependent gene expression. Here, (-)-PCB 136 was a significantly more potent inducer of PXR activity than (+)-PCB 136. Taken together, the present results indicate that at least two nuclear receptors participating in endocrine regulation or metabolism, ER and PXR, could be regulated in an atropselective manner by chiral PCB 136. The enantioselective enrichment of PCB atropisomers in animal and human tissues may thus have significant consequences for endocrine-disrupting effects of chiral ortho-substituted PCB congeners.

A comprehensive data mining study shows that most nuclear receptors act as newly proposed homeostasis-associated molecular pattern receptors.

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Wang, Luqiao; Nanayakkara, Gayani; Yang, Qian; Tan, Hongmei; Drummer, Charles; Sun, Yu; Shao, Ying; Fu, Hangfei; Cueto, Ramon; Shan, Huimin; Bottiglieri, Teodoro; Li, Ya-Feng; Johnson, Candice; Yang, William Y; Yang, Fan; Xu, Yanjie; Xi, Hang; Liu, Weiqing; Yu, Jun; Choi, Eric T; Cheng, Xiaoshu; Wang, Hong; Yang, Xiaofeng

2017-10-24

Nuclear receptors (NRs) can regulate gene expression; therefore, they are classified as transcription factors. Despite the extensive research carried out on NRs, still several issues including (1) the expression profile of NRs in human tissues, (2) how the NR expression is modulated during atherosclerosis and metabolic diseases, and (3) the overview of the role of NRs in inflammatory conditions are not fully understood. To determine whether and how the expression of NRs are regulated in physiological/pathological conditions, we took an experimental database analysis to determine expression of all 48 known NRs in 21 human and 17 murine tissues as well as in pathological conditions. We made the following significant findings: (1) NRs are differentially expressed in tissues, which may be under regulation by oxygen sensors, angiogenesis pathway, stem cell master regulators, inflammasomes, and tissue hypo-/hypermethylation indexes; (2) NR sequence mutations are associated with increased risks for development of cancers and metabolic, cardiovascular, and autoimmune diseases; (3) NRs have less tendency to be upregulated than downregulated in cancers, and autoimmune and metabolic diseases, which may be regulated by inflammation pathways and mitochondrial energy enzymes; and (4) the innate immune sensor inflammasome/caspase-1 pathway regulates the expression of most NRs. Based on our findings, we propose a new paradigm that most nuclear receptors are anti-inflammatory homeostasis-associated molecular pattern receptors (HAMPRs). Our results have provided a novel insight on NRs as therapeutic targets in metabolic diseases, inflammations, and malignancies.

RNA-induced silencing complex (RISC) Proteins PACT, TRBP, and Dicer are SRA binding nuclear receptor coregulators.

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Redfern, Andrew D; Colley, Shane M; Beveridge, Dianne J; Ikeda, Naoya; Epis, Michael R; Li, Xia; Foulds, Charles E; Stuart, Lisa M; Barker, Andrew; Russell, Victoria J; Ramsay, Kerry; Kobelke, Simon J; Li, Xiaotao; Hatchell, Esme C; Payne, Christine; Giles, Keith M; Messineo, Adriana; Gatignol, Anne; Lanz, Rainer B; O'Malley, Bert W; Leedman, Peter J

2013-04-16

The cytoplasmic RNA-induced silencing complex (RISC) contains dsRNA binding proteins, including protein kinase RNA activator (PACT), transactivation response RNA binding protein (TRBP), and Dicer, that process pre-microRNAs into mature microRNAs (miRNAs) that target specific mRNA species for regulation. There is increasing evidence for important functional interactions between the miRNA and nuclear receptor (NR) signaling networks, with recent data showing that estrogen, acting through the estrogen receptor, can modulate initial aspects of nuclear miRNA processing. Here, we show that the cytoplasmic RISC proteins PACT, TRBP, and Dicer are steroid receptor RNA activator (SRA) binding NR coregulators that target steroid-responsive promoters and regulate NR activity and downstream gene expression. Furthermore, each of the RISC proteins, together with Argonaute 2, associates with SRA and specific pre-microRNAs in both the nucleus and cytoplasm, providing evidence for links between NR-mediated transcription and some of the factors involved in miRNA processing.

Nuclear Receptor TLX in Development and Diseases.

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Sun, Guoqiang; Cui, Qi; Shi, Yanhong

2017-01-01

The nuclear receptor TLX (NR2E1) is a transcription factor that is critical for neural development and adult neurogenesis through its actions in regulating neural stem cell proliferation, self-renewal, and fate determination. These roles are primarily executed by regulating TLX downstream target genes involved in myriad pathways such as cell cycle progression, RNA processing, angiogenesis, and senescence. Recent studies suggest that dysregulation of TLX pathways plays an important role in the pathogenesis of human neurological disorders and brain tumors. Here, we will highlight recent progress in the roles of TLX in brain development and adult neurogenesis, and the relevance of TLX to neurological diseases and brain tumors. We will also discuss the potential of TLX as a therapeutic target for these disorders. © 2017 Elsevier Inc. All rights reserved.

Development of an image analysis screen for estrogen receptor alpha (ERα) ligands through measurement of nuclear translocation dynamics.

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Dull, Angie; Goncharova, Ekaterina; Hager, Gordon; McMahon, James B

2010-11-01

We have developed a robust high-content assay to screen for novel estrogen receptor alpha (ERα) agonists and antagonists by quantitation of cytoplasmic to nuclear translocation of an estrogen receptor chimera in 384-well plates. The screen utilizes a green fluorescent protein tagged-glucocorticoid/estrogen receptor (GFP-GRER) chimera which consisted of the N-terminus of the glucocorticoid receptor fused to the human ER ligand binding domain. The GFP-GRER exhibited cytoplasmic localization in the absence of ERα ligands, and translocated to the nucleus in response to stimulation with ERα agonists or antagonists. The BD Pathway 435 imaging system was used for image acquisition, analysis of translocation dynamics, and cytotoxicity measurements. The assay was validated with known ERα agonists and antagonists, and the Library of Pharmacologically Active Compounds (LOPAC 1280). Additionally, screening of crude natural product extracts demonstrated the robustness of the assay, and the ability to quantitate the effects of toxicity on nuclear translocation dynamics. The GFP-GRER nuclear translocation assay was very robust, with z' values >0.7, CVs screening of natural product extracts. This assay has been developed for future primary screening of synthetic, pure natural products, and natural product extracts libraries available at the National Cancer Institute at Frederick. Copyright © 2010 Elsevier Ltd. All rights reserved.

Integrated in silico and in vivo approaches to investigate effects of BDE-99 mediated by the nuclear receptors on developing zebrafish.

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Zhang, Li; Jin, Yaru; Han, Zhihua; Liu, Hongling; Shi, Laihao; Hua, Xiaoxue; Doering, Jon A; Tang, Song; Giesy, John P; Yu, Hongxia

2018-03-01

One of the most abundant polybrominated diphenyl ethers (PBDEs) is 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), which persists and potentially bioaccumulates in aquatic wildlife. Previous studies in mammals have shown that BDE-99 affects development and disrupts certain endocrine functions through signaling pathways mediated by nuclear receptors. However, fewer studies have investigated the potential of BDE-99 to interact with nuclear receptors in aquatic vertebrates such as fish. In the present study, interactions between BDE-99 and nuclear receptors were investigated by in silico and in vivo approaches. This PBDE was able to dock into the ligand-binding domain of zebrafish aryl hydrocarbon receptor 2 (AhR2) and pregnane X receptor (PXR). It had a significant effect on the transcriptional profiles of genes associated with AhR or PXR. Based on the developed cytoscape of all zebrafish genes, it was also inferred that AhR and PXR could interact via cross-talk. In addition, both the in silico and in vivo approaches found that BDE-99 affected peroxisome proliferator-activated receptor alpha (PPARα), glucocorticoid receptor, and thyroid receptor. Collectively, our results demonstrate for the first time detailed in silico evidence that BDE-99 can bind to and interact with zebrafish AhR and PXR. These findings can be used to elaborate the molecular mechanism of BDE-99 and guide more objective environmental risk assessments. Environ Toxicol Chem 2018;37:780-787. © 2017 SETAC. © 2017 SETAC.

Adenosine Receptor Heteromers and their Integrative Role in Striatal Function

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Sergi Ferré

2007-01-01

Full Text Available By analyzing the functional role of adenosine receptor heteromers, we review a series of new concepts that should modify our classical views of neurotransmission in the central nervous system (CNS. Neurotransmitter receptors cannot be considered as single functional units anymore. Heteromerization of neurotransmitter receptors confers functional entities that possess different biochemical characteristics with respect to the individual components of the heteromer. Some of these characteristics can be used as a “biochemical fingerprint” to identify neurotransmitter receptor heteromers in the CNS. This is exemplified by changes in binding characteristics that are dependent on coactivation of the receptor units of different adenosine receptor heteromers. Neurotransmitter receptor heteromers can act as “processors” of computations that modulate cell signaling, sometimes critically involved in the control of pre- and postsynaptic neurotransmission. For instance, the adenosine A1-A2A receptor heteromer acts as a concentration-dependent switch that controls striatal glutamatergic neurotransmission. Neurotransmitter receptor heteromers play a particularly important integrative role in the “local module” (the minimal portion of one or more neurons and/or one or more glial cells that operates as an independent integrative unit, where they act as processors mediating computations that convey information from diverse volume-transmitted signals. For instance, the adenosine A2A-dopamine D2 receptor heteromers work as integrators of two different neurotransmitters in the striatal spine module.

Regulation of Brown and White Adipocyte Transcriptome by the Transcriptional Coactivator NT-PGC-1α.

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Jihyun Kim

Full Text Available The β3-adrenergic receptor (AR signaling pathway is a major component of adaptive thermogenesis in brown and white adipose tissue during cold acclimation. The β3-AR signaling highly induces the expression of transcriptional coactivator PGC-1α and its splice variant N-terminal (NT-PGC-1α, which in turn activate the transcription program of adaptive thermogenesis by co-activating a number of transcription factors. We previously reported that NT-PGC-1α is able to increase mitochondrial number and activity in cultured brown adipocytes by promoting the expression of mitochondrial and thermogenic genes. In the present study, we performed genome-wide profiling of NT-PGC-1α-responsive genes in brown adipocytes to identify genes potentially regulated by NT-PGC-1α. Canonical pathway analysis revealed that a number of genes upregulated by NT-PGC-1α are highly enriched in mitochondrial pathways including fatty acid transport and β-oxidation, TCA cycle and electron transport system, thus reinforcing the crucial role of NT-PGC-1α in the enhancement of mitochondrial function. Moreover, canonical pathway analysis of NT-PGC-1α-responsive genes identified several metabolic pathways including glycolysis and fatty acid synthesis. In order to validate the identified genes in vivo, we utilized the FL-PGC-1α-/- mouse that is deficient in full-length PGC-1α (FL-PGC-1α but expresses a slightly shorter and functionally equivalent form of NT-PGC-1α (NT-PGC-1α254. The β3-AR-induced increase of NT-PGC-1α254 in FL-PGC-1α-/- brown and white adipose tissue was closely associated with elevated expression of genes involved in thermogenesis, mitochondrial oxidative metabolism, glycolysis and fatty acid synthesis. Increased adipose tissue thermogenesis by β3-AR activation resulted in attenuation of adipose tissue expansion in FL-PGC-1α-/- adipose tissue under the high-fat diet condition. Together, the data strengthen our previous findings that NT-PGC-1�

Surface localization of the nuclear receptor CAR in influenza A virus-infected cells

International Nuclear Information System (INIS)

Takahashi, Tadanobu; Moriyama, Yusuke; Ikari, Akira; Sugatani, Junko; Suzuki, Takashi; Miwa, Masao

2008-01-01

Constitutive active/androstane receptor CAR is a member of the nuclear receptors which regulate transcription of xenobiotic metabolism enzymes. CAR is usually localized in the cytosol and nucleus. Here, we found that CAR was localized at the cell surface of influenza A virus (IAV)-infected cells. Additionally, we demonstrated that expression of a viral envelope glycoprotein, either hemagglutinin (HA) or neuraminidase (NA), but not viral nucleoprotein (NP), was responsible for this localization. This report is the first demonstration of CAR at the surface of tissue culture cells, and suggests that CAR may exert the IAV infection mechanism

Development of Coactivator-Dependent, First-in-Class Therapies for Breast Cancer

Science.gov (United States)

2014-09-01

y. ME65CH18-Dasgupta ARI 14 December 2013 18:9 amplified in chronic lymphocytic leukemia ( CLL ). Gain of 2p chromosomal region func- tion...inCLLpatients is detected at an early stage of the disease and correlates with poor prog- nosis, indicating SRC-1 may contribute to the pathological state of CLL ...70), recent evidence points to a require- ment for coactivators in chemoresistance (71) as well as in stem cell self-renewal and pluripo- tency

Androgen Receptor Antagonism By Divalent Ethisterone Conjugates In Castrate-Resistant Prostate Cancer Cells

Science.gov (United States)

Levine, Paul M.; Lee, Eugine; Greenfield, Alex; Bonneau, Richard; Logan, Susan K.; Garabedian, Michael J.; Kirshenbaum, Kent

2013-01-01

Sustained treatment of prostate cancer with Androgen Receptor (AR) antagonists can evoke drug resistance, leading to castrate-resistant disease. Elevated activity of the AR is often associated with this highly aggressive disease state. Therefore, new therapeutic regimens that target and modulate AR activity could prove beneficial. We previously introduced a versatile chemical platform to generate competitive and non-competitive multivalent peptoid oligomer conjugates that modulate AR activity. In particular, we identified a linear and a cyclic divalent ethisterone conjugate that exhibit potent anti-proliferative properties in LNCaP-abl cells, a model of castrate-resistant prostate cancer. Here, we characterize the mechanism of action of these compounds utilizing confocal microscopy, time-resolved fluorescence resonance energy transfer, chromatin immunoprecipitation, flow cytometry, and microarray analysis. The linear conjugate competitively blocks AR action by inhibiting DNA binding. In addition, the linear conjugate does not promote AR nuclear localization or co-activator binding. In contrast, the cyclic conjugate promotes AR nuclear localization and induces cell-cycle arrest, despite its inability to compete against endogenous ligand for binding to AR in vitro. Genome-wide expression analysis reveals that gene transcripts are differentially affected by treatment with the linear or cyclic conjugate. Although the divalent ethisterone conjugates share extensive chemical similarities, we illustrate that they can antagonize the AR via distinct mechanisms of action, establishing new therapeutic strategies for potential applications in AR pharmacology. PMID:22871957

DAX1 suppresses FXR transactivity as a novel co-repressor

Energy Technology Data Exchange (ETDEWEB)

Li, Jin; Lu, Yan; Liu, Ruya; Xiong, Xuelian; Zhang, Zhijian; Zhang, Xianfeng [Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025 (China); Ning, Guang, E-mail: guangning@gmail.com.cn [Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025 (China); The Key Laboratory of Endocrine Tumors and The Division of Endocrine and Metabolic Diseases, E-Institute of Shanghai Universities, Shanghai 200025 (China); Li, Xiaoying, E-mail: lixy@sibs.ac.cn [Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025 (China); The Key Laboratory of Endocrine Tumors and The Division of Endocrine and Metabolic Diseases, E-Institute of Shanghai Universities, Shanghai 200025 (China)

2011-09-09

Highlights: {yields} DAX1 is co-localized with FXR and interacts with FXR. {yields} DAX1 acts as a negative regulator of FXR. {yields} Three LXXLL motifs in the N-terminus of DAX1 were required. {yields} DAX1 suppresses FXR transactivation by competing with co-activators. -- Abstract: Bile acid receptor FXR (farnesoid X receptor) is a key regulator of hepatic bile acid, glucose and lipid homeostasis through regulation of numerous genes involved in the process of bile acid, triglyceride and glucose metabolism. DAX1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor family due to lack of classical DNA-binding domains and acts primarily as a co-repressor of many nuclear receptors. Here, we demonstrated that DAX1 is co-localized with FXR in the nucleus and acted as a negative regulator of FXR through a physical interaction with FXR. Our study showed that over-expression of DAX1 down-regulated the expression of FXR target genes, whereas knockdown of DAX1 led to their up-regulation. Furthermore, three LXXLL motifs in the N-terminus of DAX1 were required for the full repression of FXR transactivation. In addition, our study characterized that DAX1 suppresses FXR transactivation via competing with co-activators such as SRC-1 and PGC-1{alpha}. In conclusion, DAX1 acts as a co-repressor to negatively modulate FXR transactivity.

DAX1 suppresses FXR transactivity as a novel co-repressor

International Nuclear Information System (INIS)

Li, Jin; Lu, Yan; Liu, Ruya; Xiong, Xuelian; Zhang, Zhijian; Zhang, Xianfeng; Ning, Guang; Li, Xiaoying

2011-01-01

Highlights: → DAX1 is co-localized with FXR and interacts with FXR. → DAX1 acts as a negative regulator of FXR. → Three LXXLL motifs in the N-terminus of DAX1 were required. → DAX1 suppresses FXR transactivation by competing with co-activators. -- Abstract: Bile acid receptor FXR (farnesoid X receptor) is a key regulator of hepatic bile acid, glucose and lipid homeostasis through regulation of numerous genes involved in the process of bile acid, triglyceride and glucose metabolism. DAX1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor family due to lack of classical DNA-binding domains and acts primarily as a co-repressor of many nuclear receptors. Here, we demonstrated that DAX1 is co-localized with FXR in the nucleus and acted as a negative regulator of FXR through a physical interaction with FXR. Our study showed that over-expression of DAX1 down-regulated the expression of FXR target genes, whereas knockdown of DAX1 led to their up-regulation. Furthermore, three LXXLL motifs in the N-terminus of DAX1 were required for the full repression of FXR transactivation. In addition, our study characterized that DAX1 suppresses FXR transactivation via competing with co-activators such as SRC-1 and PGC-1α. In conclusion, DAX1 acts as a co-repressor to negatively modulate FXR transactivity.

A mollusk VDR/PXR/CAR-like (NR1J) nuclear receptor provides insight into ancient detoxification mechanisms

Energy Technology Data Exchange (ETDEWEB)

Cruzeiro, Catarina, E-mail: catarinarcruzeiro@hotmail.com [ICBAS - Institute of Biomedical Sciences Abel Salazar, U. Porto - University of Porto (Portugal); CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); Lopes-Marques, Mónica, E-mail: monicaslm@hotmail.com [ICBAS - Institute of Biomedical Sciences Abel Salazar, U. Porto - University of Porto (Portugal); CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); Ruivo, Raquel, E-mail: ruivo.raquel@gmail.com [CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); Rodrigues-Oliveira, Nádia, E-mail: nadia.oliveira@ciimar.up.pt [CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); Santos, Miguel M., E-mail: santos@ciimar.up.pt [CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); FCUP - Faculty of Sciences, Department of Biology, U. Porto (Portugal); Rocha, Maria João, E-mail: mjsrocha@netcabo.pt [ICBAS - Institute of Biomedical Sciences Abel Salazar, U. Porto - University of Porto (Portugal); CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); Rocha, Eduardo, E-mail: erocha@icbas.up.pt [ICBAS - Institute of Biomedical Sciences Abel Salazar, U. Porto - University of Porto (Portugal); CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); Castro, L. Filipe C., E-mail: filipe.castro@ciimar.up.pt [CIIMAR/CIMAR - Interdisciplinary Center of Marine and Environmental Research, U. Porto (Portugal); FCUP - Faculty of Sciences, Department of Biology, U. Porto (Portugal)

2016-05-15

Highlights: • A nuclear receptor orthologue of the NR1J group is isolated from a mollusc. • The molluscan NR1J transactivates gene expression upon exposure to okadaic acid but not a pesticide, esfenvarelate and triclosan. • Lineage specific gene duplications and gene loss have occurred in the NR1J of protostomes with likely impacts on detoxification mechanisms. - Abstract: The origin and diversification of the metazoan endocrine systems represents a fundamental research issue in biology. Nuclear receptors are critical components of these systems. A particular group named VDR/PXR/CAR (NR1I/J) is central in the mediation of detoxification responses. While orthologues have been thoroughly characterized in vertebrates, a sparse representation is currently available for invertebrates. Here, we provide the first isolation and characterization of a lophotrochozoan protostome VDR/PXR/CAR nuclear receptor (NR1J), in the estuarine bivalve the peppery furrow shell (Scrobicularia plana). Using a reporter gene assay, we evaluated the xenobiotic receptor plasticity comparing the human PXR with the S. plana NR1Jβ. Our results show that the molluscan receptor responds to a natural toxin (okadaic acid) in a similar fashion to that reported for other invertebrates. In contrast, the pesticide esfenvalerate displayed a unique response, since it down regulated transactivation at higher concentrations, while for triclosan no response was observed. Additionally, we uncovered lineage specific gene duplications and gene loss in the gene group encoding NRs in protostomes with likely impacts on the complexity of detoxification mechanisms across different phyla. Our findings pave the way for the development of multi-specific sensor tools to screen xenobiotic compounds acting via the NR1I/J group.

A mollusk VDR/PXR/CAR-like (NR1J) nuclear receptor provides insight into ancient detoxification mechanisms

International Nuclear Information System (INIS)

Cruzeiro, Catarina; Lopes-Marques, Mónica; Ruivo, Raquel; Rodrigues-Oliveira, Nádia; Santos, Miguel M.; Rocha, Maria João; Rocha, Eduardo; Castro, L. Filipe C.

2016-01-01

Highlights: • A nuclear receptor orthologue of the NR1J group is isolated from a mollusc. • The molluscan NR1J transactivates gene expression upon exposure to okadaic acid but not a pesticide, esfenvarelate and triclosan. • Lineage specific gene duplications and gene loss have occurred in the NR1J of protostomes with likely impacts on detoxification mechanisms. - Abstract: The origin and diversification of the metazoan endocrine systems represents a fundamental research issue in biology. Nuclear receptors are critical components of these systems. A particular group named VDR/PXR/CAR (NR1I/J) is central in the mediation of detoxification responses. While orthologues have been thoroughly characterized in vertebrates, a sparse representation is currently available for invertebrates. Here, we provide the first isolation and characterization of a lophotrochozoan protostome VDR/PXR/CAR nuclear receptor (NR1J), in the estuarine bivalve the peppery furrow shell (Scrobicularia plana). Using a reporter gene assay, we evaluated the xenobiotic receptor plasticity comparing the human PXR with the S. plana NR1Jβ. Our results show that the molluscan receptor responds to a natural toxin (okadaic acid) in a similar fashion to that reported for other invertebrates. In contrast, the pesticide esfenvalerate displayed a unique response, since it down regulated transactivation at higher concentrations, while for triclosan no response was observed. Additionally, we uncovered lineage specific gene duplications and gene loss in the gene group encoding NRs in protostomes with likely impacts on the complexity of detoxification mechanisms across different phyla. Our findings pave the way for the development of multi-specific sensor tools to screen xenobiotic compounds acting via the NR1I/J group.

Nuclear receptor TLX prevents retinal dystrophy and recruits the corepressor atrophin1.

Science.gov (United States)

Zhang, Chun-Li; Zou, Yuhua; Yu, Ruth T; Gage, Fred H; Evans, Ronald M

2006-05-15

During mammalian embryogenesis, precise coordination of progenitor cell proliferation and differentiation is essential for proper organ size and function. The involvement of TLX (NR2E1), an orphan nuclear receptor, has been implicated in ocular development, as Tlx-/- mice exhibit visual impairment. Using genetic and biochemical approaches, we show that TLX modulates retinal progenitor cell proliferation and cell cycle re-entry by directly regulating the expression of Pten and its target cyclin D1. Additionally, TLX finely tunes the progenitor differentiation program by modulating the phospholipase C and mitogen-activated protein kinase (MAPK) pathways and the expression of an array of cell type-specific transcriptional regulators. Consequently, Tlx-/- mice have a dramatic reduction in retina thickness and enhanced generation of S-cones, and develop severe early onset retinal dystrophy. Furthermore, TLX interacts with atrophin1 (Atn1), a corepressor that is involved in human neurodegenerative dentatorubral-pallidoluysian atrophy (DRPLA) and that is essential for development of multiple tissues. Together, these results reveal a molecular strategy by which an orphan nuclear receptor can precisely orchestrate tissue-specific proliferation and differentiation programs to prevent retinal malformation and degeneration.

NR4A nuclear receptors mediate carnitine palmitoyltransferase 1A gene expression by the rexinoid HX600

Energy Technology Data Exchange (ETDEWEB)

Ishizawa, Michiyasu [Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610 (Japan); Kagechika, Hiroyuki [Graduate School of Biomedical Science, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Makishima, Makoto, E-mail: makishima.makoto@nihon-u.ac.jp [Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610 (Japan)

2012-02-24

Highlights: Black-Right-Pointing-Pointer The function of RXR heterodimers with NR4 receptors remains unknown. Black-Right-Pointing-Pointer The RXR ligand HX600 induces expression of carnitine palmitoyltransferase 1A (CPT1A). Black-Right-Pointing-Pointer HX600-induced CPT1A expression is mediated by the NR4 receptors, Nur77 and NURR1. Black-Right-Pointing-Pointer CPT1A induction by HX600 is not mediated by de novo protein synthesis. Black-Right-Pointing-Pointer CPT1A could be a target of the Nur77-RXR and NURR1-RXR heterodimers. -- Abstract: Retinoid X receptors (RXRs) are members of the nuclear receptor superfamily and can be activated by 9-cis retinoic acid (9CRA). RXRs form homodimers and heterodimers with other nuclear receptors such as the retinoic acid receptor and NR4 subfamily nuclear receptors, Nur77 and NURR1. Potential physiological roles of the Nur77-RXR and NURR1-RXR heterodimers have not been elucidated. In this study, we identified a gene regulated by these heterodimers utilizing HX600, a selective RXR agonist for Nur77-RXR and NURR1-RXR. While 9CRA induced many genes, including RAR-target genes, HX600 effectively induced only carnitine palmitoyltransferase 1A (CPT1A) in human teratocarcinoma NT2/D1 cells, which express RXR{alpha}, Nur77 and NURR1. HX600 also increased CPT1A expression in human embryonic kidney (HEK) 293 cells and hepatocyte-derived HepG2 cells. Although HX600 induced CPT1A less effectively than 9CRA, overexpression of Nur77 or NURR1 increased the HX600 response to levels similar to 9CRA in NT2/D1 and HEK293 cells. A dominant-negative form of Nur77 or NURR1 repressed the induction of CPT1A by HX600. A protein synthesis inhibitor did not alter HX600-dependent CPT1A induction. Thus, the rexinoid HX600 directly induces expression of CPT1A through a Nur77 or NURR1-mediated mechanism. CPT1A, a gene involved in fatty acid {beta}-oxidation, could be a target of RXR-NR4 receptor heterodimers.

Novel nuclear localization and potential function of insulin-like growth factor-1 receptor/insulin receptor hybrid in corneal epithelial cells.

Directory of Open Access Journals (Sweden)

Yu-Chieh Wu

Full Text Available BACKGROUND: Type I insulin-like growth factor receptor (IGF-1R and insulin receptor (INSR are highly homologous molecules, which can heterodimerize to form an IGF-1R/INSR hybrid (Hybrid-R. The presence and biological significance of the Hybrid-R in human corneal epithelium has not yet been established. In addition, while nuclear localization of IGF-1R was recently reported in cancer cells and human corneal epithelial cells, the function and profile of nuclear IGF-1R is unknown. In this study, we characterized the nuclear localization and function of the Hybrid-R and the role of IGF-1/IGF-1R and Hybrid-R signaling in the human corneal epithelium. METHODOLOGY/PRINCIPLE FINDINGS: IGF-1-mediated signaling and cell growth were examined in a human telomerized corneal epithelial (hTCEpi cell line using co-immunoprecipitation, immunoblotting and cell proliferation assays. The presence of Hybrid-R in hTCEpi and primary cultured human corneal epithelial cells was confirmed by immunofluorescence and reciprocal immunoprecipitation of whole cell lysates. We found that IGF-1 stimulated Akt and promoted cell growth through IGF-1R activation, which was independent of the Hybrid-R. The presence of Hybrid-R, but not IGF-1R/IGF-1R, was detected in nuclear extracts. Knockdown of INSR by small interfering RNA resulted in depletion of the INSR/INSR and preferential formation of Hybrid-R. Chromatin-immunoprecipitation sequencing assay with anti-IGF-1R or anti-INSR was subsequently performed to identify potential genomic targets responsible for critical homeostatic regulatory pathways. CONCLUSION/SIGNIFICANCE: In contrast to previous reports on nuclear localized IGF-1R, this is the first report identifying the nuclear localization of Hybrid-R in an epithelial cell line. The identification of a nuclear Hybrid-R and novel genomic targets suggests that IGF-1R traffics to the nucleus as an IGF-1R/INSR heterotetrameric complex to regulate corneal epithelial homeostatic

Antidiabetic phospholipid-nuclear receptor complex reveals the mechanism for phospholipid-driven gene regulation

Energy Technology Data Exchange (ETDEWEB)

Musille, Paul M; Pathak, Manish C; Lauer, Janelle L; Hudson, William H; Griffin, Patrick R; Ortlund, Eric A [Emory-MED; (Scripps)

2013-01-31

The human nuclear receptor liver receptor homolog-1 (LRH-1) has an important role in controlling lipid and cholesterol homeostasis and is a potential target for the treatment of diabetes and hepatic diseases. LRH-1 is known to bind phospholipids, but the role of phospholipids in controlling LRH-1 activation remains highly debated. Here we describe the structure of both apo LRH-1 and LRH-1 in complex with the antidiabetic phospholipid dilauroylphosphatidylcholine (DLPC). Together with hydrogen-deuterium exchange MS and functional data, our studies show that DLPC binding is a dynamic process that alters co-regulator selectivity. We show that the lipid-free receptor undergoes previously unrecognized structural fluctuations, allowing it to interact with widely expressed co-repressors. These observations enhance our understanding of LRH-1 regulation and highlight its importance as a new therapeutic target for controlling diabetes.

Kaposi's sarcoma-associated herpesvirus-encoded LANA associates with glucocorticoid receptor and enhances its transcriptional activities

International Nuclear Information System (INIS)

Togi, Sumihito; Nakasuji, Misa; Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Kitai, Yuichi; Kon, Shigeyuki; Oritani, Kenji; Matsuda, Tadashi

2015-01-01

Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA), which interacts with cellular proteins, plays a central role in modification of viral and/or cellular gene expression. Here, we show that LANA associates with glucocorticoid receptor (GR), and that LANA enhances the transcriptional activity of GR. Co-immunoprecipitation revealed a physical interaction between LANA and GR in transiently transfected 293T and HeLa cells. In human B-lymphoma cells, LANA overexpression enhanced GR activity and cell growth suppression following glucocorticoid stimulation. Furthermore, confocal microscopy showed that activated GR was bound to LANA and accumulated in the nucleus, leading to an increase in binding of activated GR to the glucocorticoid response element of target genes. Taken together, KSHV-derived LANA acts as a transcriptional co-activator of GR. Our results might suggest a careful use of glucocorticoids in the treatment of patients with KSHV-related malignancies such as Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. - Highlights: • KSHV-LANA enhances the transcriptional activity of GR in 293T and HeLa cells. • KSHV-LANA physically associates with GR. • KSHV-LANA enhances GR activation and cell growth suppression in human B-lymphocytes. • KSHV-LANA influences the nuclear retention and DNA binding activity of GR

Kaposi's sarcoma-associated herpesvirus-encoded LANA associates with glucocorticoid receptor and enhances its transcriptional activities

Energy Technology Data Exchange (ETDEWEB)

Togi, Sumihito; Nakasuji, Misa; Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Kitai, Yuichi; Kon, Shigeyuki [Department of Immunology, Graduate School of Pharmaceutical Sciences Hokkaido University, Sapporo 060-0812 (Japan); Oritani, Kenji [Department of Hematology and Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Matsuda, Tadashi, E-mail: tmatsuda@pharm.hokudai.ac.jp [Department of Immunology, Graduate School of Pharmaceutical Sciences Hokkaido University, Sapporo 060-0812 (Japan)

2015-07-31

Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA), which interacts with cellular proteins, plays a central role in modification of viral and/or cellular gene expression. Here, we show that LANA associates with glucocorticoid receptor (GR), and that LANA enhances the transcriptional activity of GR. Co-immunoprecipitation revealed a physical interaction between LANA and GR in transiently transfected 293T and HeLa cells. In human B-lymphoma cells, LANA overexpression enhanced GR activity and cell growth suppression following glucocorticoid stimulation. Furthermore, confocal microscopy showed that activated GR was bound to LANA and accumulated in the nucleus, leading to an increase in binding of activated GR to the glucocorticoid response element of target genes. Taken together, KSHV-derived LANA acts as a transcriptional co-activator of GR. Our results might suggest a careful use of glucocorticoids in the treatment of patients with KSHV-related malignancies such as Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. - Highlights: • KSHV-LANA enhances the transcriptional activity of GR in 293T and HeLa cells. • KSHV-LANA physically associates with GR. • KSHV-LANA enhances GR activation and cell growth suppression in human B-lymphocytes. • KSHV-LANA influences the nuclear retention and DNA binding activity of GR.

Obstructing Androgen Receptor Activation in Prostate Cancer Cells Through Post-translational Modification by NEDD8

Science.gov (United States)

2012-11-01

FACS flow cytometer analysis . In addition, we will measure the steady state protein level of p53, p21, p27, and pRb. In the Jab1 silencing cell...affected by DHT treatment, and the endogenous AR level was not affected by Jab1 silencing. Interestingly, Western blot analysis of immunoprecipitated AR...Avantaggiati, and R. G. Pestell . 2003. Acetylation of androgen receptor enhances coactivator binding and promotes prostate cancer cell growth. Mol

Abnormal XPD-induced nuclear receptor transactivation in DNA repair disorders: trichothiodystrophy and xeroderma pigmentosum.

Science.gov (United States)

Zhou, Xiaolong; Khan, Sikandar G; Tamura, Deborah; Ueda, Takahiro; Boyle, Jennifer; Compe, Emmanuel; Egly, Jean-Marc; DiGiovanna, John J; Kraemer, Kenneth H

2013-08-01

XPD (ERCC2) is a DNA helicase involved in nucleotide excision repair and in transcription as a structural bridge tying the transcription factor IIH (TFIIH) core with the cdk-activating kinase complex, which phosphorylates nuclear receptors. Mutations in XPD are associated with several different phenotypes, including trichothiodystrophy (TTD), with sulfur-deficient brittle hair, bone defects, and developmental abnormalities without skin cancer, xeroderma pigmentosum (XP), with pigmentary abnormalities and increased skin cancer, or XP/TTD with combined features, including skin cancer. We describe the varied clinical features and mutations in nine patients examined at the National Institutes of Health who were compound heterozygotes for XPD mutations but had different clinical phenotypes: four TTD, three XP, and two combined XP/TTD. We studied TFIIH-dependent transactivation by nuclear receptor for vitamin D (VDR) and thyroid in cells from these patients. The vitamin D stimulation ratio of CYP24 and osteopontin was associated with specific pairs of mutations (reduced in 5, elevated in 1) but not correlated with distinct clinical phenotypes. Thyroid receptor stimulation ratio for KLF9 was not significantly different from normal. XPD mutations frequently were associated with abnormal VDR stimulation in compound heterozygote patients with TTD, XP, or XP/TTD.

SRC-1 regulates blood pressure and aortic stiffness in female mice

Science.gov (United States)

Framingham Heart Study suggests that dysfunction of steroid receptor coactivator-1 may be involved in the development of hypertension. However, there is no functional evidence linking steroid receptor coactivator-1 to the regulation of blood pressure. We used immunohistochemistry to map the expressi...

Transcription control and neuronal differentiation by agents that activate the LXR nuclear receptor family.

Science.gov (United States)

Schmidt, A; Vogel, R; Holloway, M K; Rutledge, S J; Friedman, O; Yang, Z; Rodan, G A; Friedman, E

1999-09-10

LXR and PPAR receptors belong to the nuclear receptor superfamily of transcriptional activating factors. Using ligand-dependent transcription assays, we found that 5-tetradecyloxy-2-furancarboxylic acid (TOFA) transactivates chimeric receptors composed of the glucocorticoid receptor DNA binding domain and the ligand binding regions of PPARalpha, PPARbeta (NUC-1) and LXRbeta (NER) receptors. In the same assays, ligands for PPARs (oleic acid, WY-14643 and L-631,033) and LXRs (hydroxycholesterols) maintain their respective receptor selectivity. TOFA and hydroxycholesterols also stimulate transcription from a minimal fibrinogen promoter that is under the control of AP-1 or NF-kappaB transcription factor binding sites. In addition to their effects on transcription, these LXRbeta activators induce neuronal differentiation in rat pheochromocytoma cells. TOFA and the natural LXR agonist, 22 (R)-hydroxycholesterol, stimulate neurite outgrowth in 55 and 28% of cells, respectively. No neurite outgrowth was induced by the related 22(S)-hydroxycholesterol, which does not activate the LXR family. These results suggest that the hydroxycholesterol signaling pathway has a complex effect on transcription that mediates the activity of TOFA and hydroxycholesterol on neuronal differentiation in pheochromocytoma cells.

Orphan nuclear receptor TR3 acts in autophagic cell death via mitochondrial signaling pathway.

Science.gov (United States)

Wang, Wei-jia; Wang, Yuan; Chen, Hang-zi; Xing, Yong-zhen; Li, Feng-wei; Zhang, Qian; Zhou, Bo; Zhang, Hong-kui; Zhang, Jie; Bian, Xue-li; Li, Li; Liu, Yuan; Zhao, Bi-xing; Chen, Yan; Wu, Rong; Li, An-zhong; Yao, Lu-ming; Chen, Ping; Zhang, Yi; Tian, Xu-yang; Beermann, Friedrich; Wu, Mian; Han, Jiahuai; Huang, Pei-qiang; Lin, Tianwei; Wu, Qiao

2014-02-01

Autophagy is linked to cell death, yet the associated mechanisms are largely undercharacterized. We discovered that melanoma, which is generally resistant to drug-induced apoptosis, can undergo autophagic cell death with the participation of orphan nuclear receptor TR3. A sequence of molecular events leading to cellular demise is launched by a specific chemical compound, 1-(3,4,5-trihydroxyphenyl)nonan-1-one, newly acquired from screening a library of TR3-targeting compounds. The autophagic cascade comprises TR3 translocation to mitochondria through interaction with the mitochondrial outer membrane protein Nix, crossing into the mitochondrial inner membrane through Tom40 and Tom70 channel proteins, dissipation of mitochondrial membrane potential by the permeability transition pore complex ANT1-VDAC1 and induction of autophagy. This process leads to excessive mitochondria clearance and irreversible cell death. It implicates a new approach to melanoma therapy through activation of a mitochondrial signaling pathway that integrates a nuclear receptor with autophagy for cell death.

Inositol polyphosphate multikinase is a coactivator for serum response factor-dependent induction of immediate early genes

Science.gov (United States)

Kim, Eunha; Tyagi, Richa; Lee, Joo-Young; Park, Jina; Kim, Young-ran; Beon, Jiyoon; Chen, Po Yu; Cha, Jiyoung Y.; Snyder, Solomon H.; Kim, Seyun

2013-01-01

Inositol polyphosphate multikinase (IPMK) is a notably pleiotropic protein. It displays both inositol phosphate kinase and phosphatidylinositol kinase catalytic activities. Noncatalytically, IPMK stabilizes the mammalian target of rapamycin complex 1 and acts as a transcriptional coactivator for CREB-binding protein/E1A binding protein p300 and tumor suppressor protein p53. Serum response factor (SRF) is a major transcription factor for a wide range of immediate early genes. We report that IPMK, in a noncatalytic role, is a transcriptional coactivator for SRF mediating the transcription of immediate early genes. Stimulation by serum of many immediate early genes is greatly reduced by IPMK deletion. IPMK stimulates expression of these genes, an influence also displayed by catalytically inactive IPMK. IPMK acts by binding directly to SRF and thereby enhancing interactions of SRF with the serum response element of diverse genes. PMID:24248338

Nitric oxide coordinates metabolism, growth, and development via the nuclear receptor E75.

Science.gov (United States)

Cáceres, Lucía; Necakov, Aleksandar S; Schwartz, Carol; Kimber, Sandra; Roberts, Ian J H; Krause, Henry M

2011-07-15

Nitric oxide gas acts as a short-range signaling molecule in a vast array of important physiological processes, many of which include major changes in gene expression. How these genomic responses are induced, however, is poorly understood. Here, using genetic and chemical manipulations, we show that nitric oxide is produced in the Drosophila prothoracic gland, where it acts via the nuclear receptor ecdysone-induced protein 75 (E75), reversing its ability to interfere with its heterodimer partner, Drosophila hormone receptor 3 (DHR3). Manipulation of these interactions leads to gross alterations in feeding behavior, fat deposition, and developmental timing. These neuroendocrine interactions and consequences appear to be conserved in vertebrates.

Structural basis for corepressor assembly by the orphan nuclear receptor TLX

OpenAIRE

Zhi, Xiaoyong; Zhou, X. Edward; He, Yuanzheng; Searose-Xu, Kelvin; Zhang, Chun-Li; Tsai, Chih-Cheng; Melcher, Karsten; Xu, H. Eric

2015-01-01

The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Zhi et al. report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. Mutations that weaken the TLX–Atrophin interaction compromise the repressive activity of TLX. In addition, mutations...

Tumour nuclear oestrogen receptor beta 1 correlates inversely with parathyroid tumour weight.

Science.gov (United States)

Haglund, Felix; Rosin, Gustaf; Nilsson, Inga-Lena; Juhlin, C Christofer; Pernow, Ylva; Norenstedt, Sophie; Dinets, Andrii; Larsson, Catharina; Hartman, Johan; Höög, Anders

2015-03-01

Primary hyperparathyroidism (PHPT) is a common endocrinopathy, frequently caused by a parathyroid adenoma, rarely by a parathyroid carcinoma that lacks effective oncological treatment. As the majority of cases are present in postmenopausal women, oestrogen signalling has been implicated in the tumourigenesis. Oestrogen receptor beta 1 (ERB1) and ERB2 have been recently identified in parathyroid adenomas, the former inducing genes coupled to tumour apoptosis. We applied immunohistochemistry and slide digitalisation to quantify nuclear ERB1 and ERB2 in 172 parathyroid adenomas, atypical adenomas and carcinomas, and ten normal parathyroid glands. All the normal parathyroid glands expressed ERB1 and ERB2. The majority of tumours expressed ERB1 (70.6%) at varying intensities, and ERB2 (96.5%) at strong intensities. Parathyroid carcinomas expressed ERB1 in three out of six cases and ERB2 in five out of six cases. The intensity of tumour nuclear ERB1 staining significantly correlated inversely with tumour weight (P=0.011), and patients whose tumours were classified as ERB1-negative had significantly greater tumour weight as well as higher serum calcium (P=0.002) and parathyroid hormone levels (P=0.003). Additionally, tumour nuclear ERB1 was not expressed differentially with respect to sex or age of the patient. Levels of tumour nuclear ERB2 did not correlate with clinical characteristics. In conclusion, decreased ERB1 immunoreactivity is associated with increased tumour weight in parathyroid adenomas. Given the previously reported correlation with tumour-suppressive signalling, selective oestrogen receptor modulation (SERMs) may play a role in the treatment of parathyroid carcinomas. Future studies of SERMs and oestrogen treatment in PHPT should consider tumour weight as a potential factor in pharmacological responsiveness. © 2015 The authors.

WORKABILITY OF A MANAGEMENT CONTROL MODEL IN SERVICE ORGANIZATIONS: A COMPARATIVE STUDY OF REACTIVE, PROACTIVE AND COACTIVE PHILOSOPHIES

Directory of Open Access Journals (Sweden)

Joshua Onome Imoniana

2006-11-01

Full Text Available The main objective of this study was to compare and contrast the three philosophies of management control models in the process of decision-making, namely reactive, proactive and the coactive. Research methodology was based on literature review and descriptive/exploratory approach. Additionally, a survey of 20 service organizations was carried out in order to make the analysis wider-reaching. In order to do that, the following steps were followed: firstly, fundamentals of reactive, proactive and coactive models were highlighted; secondly, management behaviors in the three approaches were compared, with concepts and their practical application being highlighted, thus retrieving managerial relationships in the organization. In so doing, we draw the hypothesis that middle and top managers who adopt control models that are distant from a more coactive one, usually spend a greater number of working hours in problem-solving, leaving little or no time for planning purposes. Finally, for study consolidation purpose, we have adopted qualitative data collection, whereby a content analysis was carried out with the assistance of six categories. Results have shown the need for a change in management paradigms so that firms are not only compared through financial perspectives, without considering the analysis of management control models which, according to this study, directly influence the operational results of the organizations.

Nuclear receptors and metabolism: from feast to famine.

Science.gov (United States)

Hong, Suk-Hyun; Ahmadian, Maryam; Yu, Ruth T; Atkins, Annette R; Downes, Michael; Evans, Ronald M

2014-05-01

The ability to adapt to cycles of feast and famine is critical for survival. Communication between multiple metabolic organs must be integrated to properly metabolise nutrients. By controlling networks of genes in major metabolic organs, nuclear hormone receptors (NHRs) play central roles in regulating metabolism in a tissue-specific manner. NHRs also establish daily rhythmicity by controlling the expression of core clock genes both centrally and peripherally. Recent findings show that many of the metabolic effects of NHRs are mediated through certain members of the fibroblast growth factor (FGF) family. This review focuses on the roles of NHRs in critical metabolic organs, including adipose tissue, liver and muscle, during the fed and fasted states, as well as their roles in circadian metabolism and downstream regulation of FGFs.

A Novel Integrative Mechanism in Anxiolytic Behavior Induced by Galanin 2/Neuropeptide Y Y1 Receptor Interactions on Medial Paracapsular Intercalated Amygdala in Rats

Directory of Open Access Journals (Sweden)

Manuel Narváez

2018-05-01

Full Text Available Anxiety is evoked by a threatening situation and display adaptive or defensive behaviors, found similarly in animals and humans. Neuropeptide Y (NPY Y1 receptor (NPYY1R and Galanin (GAL receptor 2 (GALR2 interact in several regions of the limbic system, including the amygdala. In a previous study, GALR2 enhanced NPYY1R mediated anxiolytic actions on spatiotemporal parameters in the open field and elevated plus maze, involving the formation of GALR2/NPYY1R heteroreceptor complexes in the amygdala. Moreover, the inclusion of complementary ethological parameters provides a more comprehensive profile on the anxiolytic effects of a treatment. The purpose of the current study is to evaluate the anxiolytic effects and circuit activity modifications caused by coactivation of GALR2 and NPYY1R. Ethological measurements were performed in the open field, the elevated plus-maze and the light-dark box, together with immediate early gene expression analysis within the amygdala-hypothalamus-periaqueductal gray (PAG axis, as well as in situ proximity ligation assay (PLA to demonstrate the formation of GALR2/NPYY1R heteroreceptor complexes. GALR2 and NPYY1R coactivation resulted in anxiolytic behaviors such as increased rearing and head-dipping, reduced stretch attend postures and freezing compared to single agonist or aCSF injection. Neuronal activity indicated by cFos expression was decreased in the dorsolateral paracapsular intercalated (ITCp-dl subregion of the amygdala, ventromedial hypothalamic (VMH nucleus and ventrolateral part of the periaqueductal gray (vlPAG, while increased in the perifornical nucleus of the hypothalamus (PFX following coactivation of GALR2 and NPYY1R. Moreover, an increased density of GALR2/NPYY1R heteroreceptor complexes was explicitly observed in ITCp-dl, following GALR2 and NPYY1R coactivation. Besides, knockdown of GALR2 was found to reduce the density of complexes in ITCp-dl. Taken together, these results open up the possibility

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...

Tennis players show a lower coactivation of the elbow antagonist muscles during isokinetic exercises.

Science.gov (United States)

Bazzucchi, Ilenia; Riccio, Maria Elena; Felici, Francesco

2008-10-01

Previous studies have suggested that muscle coactivation could be reduced by a recurrent activity (training, daily activities). If this was correct, skilled athletes should show a specific muscle activation pattern with a low level of coactivation of muscles which are typically involved in their discipline. In particular, the aim of this study was to verify the hypothesis that the amount of antagonist activation of biceps brachii (BB) and triceps brachii (TB) is different between tennis players and non-players individuals during maximal isokinetic contractions. Ten young healthy men and eight male tennis players participated in the study. The surface electromyographic signals (sEMG) were recorded from the BB and TB muscles during three maximal voluntary isometric contractions (MVC) of elbow flexors and extensors and a set of three maximal elbow flexions and extensions at 15 degrees , 30 degrees , 60 degrees , 120 degrees , 180 degrees and 240 degrees /s. Normalized root mean square (RMS) of sEMG was calculated as an index of sEMG amplitude. Antagonist activation (%RMSmax) of TB was significantly lower in tennis players (from 14.0+/-7.9% at MVC to 16.3+/-8.9% at 240 degrees /s) with respect to non-players (from 27.7+/-19.7% at MVC to 38.7+/-17.6% at 240 degrees /s) at all angular velocities. Contrary to non-players, tennis players did not show any difference in antagonist activation between BB and TB muscles. Tennis players, with a constant practice in controlling forces around the elbow joint, learn how to reduce coactivation of muscles involved in the control of this joint. This has been shown by the lower antagonist muscular activity of triceps brachii muscle during isokinetic elbow flexion found in tennis players with respect to non-players.

Cervical Muscle Strength and Muscle Coactivation During Isometric Contractions in Patients With Migraine: A Cross-Sectional Study.

Science.gov (United States)

Florencio, Lidiane Lima; de Oliveira, Anamaria Siriani; Carvalho, Gabriela Ferreira; Tolentino, Gabriella de Almeida; Dach, Fabiola; Bigal, Marcelo Eduardo; Fernández-de-las-Peñas, César; Bevilaqua Grossi, Débora

2015-01-01

This cross-sectional study investigated potential differences in cervical musculature in groups of migraine headaches vs. non-headache controls. Differences in cervical muscle strength and antagonist coactivation during maximal isometric voluntary contraction (MIVC) were analyzed between individuals with migraine and non-headache subjects and relationships between force with migraine and neck pain clinical aspects. A customized hand-held dynamometer was used to assess cervical flexion, extension, and bilateral lateral flexion strength in subjects with episodic migraine (n=31), chronic migraine (n = 21) and healthy controls (n = 31). Surface electromyography (EMG) from sternocleidomastoid, anterior scalene, and splenius capitis muscles were recorded during MIVC to evaluate antagonist coactivation. Comparison of main outcomes among groups was conducted with one-way analysis of covariance with the presence of neck pain as covariable. Correlations between peak force and clinical variables were demonstrated by Spearman's coefficient. Chronic migraine subjects exhibited lower cervical extension force (mean diff. from controls: 4.4 N/kg; mean diff from episodic migraine: 3.7 N/kg; P = .006) and spent significantly more time to generate peak force during cervical flexion (mean diff. from controls: 0.5 seconds; P = .025) and left lateral-flexion (mean diff. from controls: 0.4 seconds; mean diff. from episodic migraine: 0.5 seconds; P = .007). Both migraine groups showed significantly higher antagonist muscle coactivity of the splenius capitis muscle (mean diff. from controls: 20%MIVC, P = .03) during cervical flexion relative to healthy controls. Cervical extension peak force was moderately associated with the migraine frequency (rs: -0.30, P = .034), neck pain frequency (rs: -0.26, P = .020), and neck pain intensity (rs: -0.27, P = .012). Patients with chronic migraine exhibit altered muscle performance, took longer to reach peak of

The monomeric orphan nuclear receptor Schistosoma mansoni Ftz-F1 dimerizes specifically and functionally with the schistosome RXR homologue, SmRXR1

International Nuclear Information System (INIS)

Bertin, Benjamin; Caby, Stephanie; Oger, Frederik; Sasorith, Souphatta; Wurtz, Jean-Marie; Pierce, Raymond J.

2005-01-01

In an attempt to understand development and differentiation processes of the parasitic blood fluke Schistosoma mansoni, several members of the nuclear receptor superfamily were cloned, including SmFtz-F1 (S. mansoni Fushi Tarazu-factor 1). The Ftz-F1 nuclear receptor subfamily only contains orphan receptors that bind to their response element as monomers. Whereas SmFtz-F1 displays these basic functional properties, we have identified an original and specific interaction between SmFtz-F1 and the schistosome RXR homologue, SmRXR1. The mammalian two-hybrid assay showed that the D, E, and F domains of SmFtz-F1 were capable of interacting specifically with the E domain of SmRXR1 but not with that of mouse RXRα. Using three-dimensional LBD homology modelling and structure-guided mutagenesis, we were able to demonstrate the essential role of exposed residues located in the dimerization interfaces of both receptors in the maintenance of the interaction. Cotransfection experiments with constructions encoding full-length nuclear receptors show that SmRXR1 potentiates the transcriptional activity of SmFtz-F1 from various promoters. Nevertheless, the lack of identification of a dimeric response element for this SmFtz-F1/SmRXR1 heterodimer seems to indicate a 'tethering' mechanism. Thus, our results suggest for the first time that a member of the Ftz-F1 family could heterodimerize functionally with a homologue of the universal heterodimerization partner of nuclear receptors. This unique property confirms that SmFtz-F1 may be involved in the development and differentiation of schistosome-specific structures

Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

Energy Technology Data Exchange (ETDEWEB)

Beildeck, Marcy E. [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States); Gelmann, Edward P. [Columbia University, Department of Medicine, New York, NY (United States); Byers, Stephen W., E-mail: byerss@georgetown.edu [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States)

2010-07-01

Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

International Nuclear Information System (INIS)

Beildeck, Marcy E.; Gelmann, Edward P.; Byers, Stephen W.

2010-01-01

Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

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

PGC-1{beta} regulates mouse carnitine-acylcarnitine translocase through estrogen-related receptor {alpha}

Energy Technology Data Exchange (ETDEWEB)

Gacias, Mar; Perez-Marti, Albert; Pujol-Vidal, Magdalena; Marrero, Pedro F. [Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona (IBUB) (Spain); Haro, Diego, E-mail: dharo@ub.edu [Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona (IBUB) (Spain); Relat, Joana [Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona (IBUB) (Spain)

2012-07-13

Highlights: Black-Right-Pointing-Pointer The Cact gene is induced in mouse skeletal muscle after 24 h of fasting. Black-Right-Pointing-Pointer The Cact gene contains a functional consensus sequence for ERR. Black-Right-Pointing-Pointer This sequence binds ERR{alpha} both in vivo and in vitro. Black-Right-Pointing-Pointer This ERRE is required for the activation of Cact expression by the PGC-1/ERR axis. Black-Right-Pointing-Pointer Our results add Cact as a genuine gene target of these transcriptional regulators. -- Abstract: Carnitine/acylcarnitine translocase (CACT) is a mitochondrial-membrane carrier proteins that mediates the transport of acylcarnitines into the mitochondrial matrix for their oxidation by the mitochondrial fatty acid-oxidation pathway. CACT deficiency causes a variety of pathological conditions, such as hypoketotic hypoglycemia, cardiac arrest, hepatomegaly, hepatic dysfunction and muscle weakness, and it can be fatal in newborns and infants. Here we report that expression of the Cact gene is induced in mouse skeletal muscle after 24 h of fasting. To gain insight into the control of Cact gene expression, we examine the transcriptional regulation of the mouse Cact gene. We show that the 5 Prime -flanking region of this gene is transcriptionally active and contains a consensus sequence for the estrogen-related receptor (ERR), a member of the nuclear receptor family of transcription factors. This sequence binds ERR{alpha}in vivo and in vitro and is required for the activation of Cact expression by the peroxisome proliferator-activated receptor gamma coactivator (PGC)-1/ERR axis. We also demonstrate that XTC790, the inverse agonist of ERR{alpha}, specifically blocks Cact activation by PGC-1{beta} in C2C12 cells.

PGC-1β regulates mouse carnitine–acylcarnitine translocase through estrogen-related receptor α

International Nuclear Information System (INIS)

Gacias, Mar; Pérez-Martí, Albert; Pujol-Vidal, Magdalena; Marrero, Pedro F.; Haro, Diego; Relat, Joana

2012-01-01

Highlights: ► The Cact gene is induced in mouse skeletal muscle after 24 h of fasting. ► The Cact gene contains a functional consensus sequence for ERR. ► This sequence binds ERRα both in vivo and in vitro. ► This ERRE is required for the activation of Cact expression by the PGC-1/ERR axis. ► Our results add Cact as a genuine gene target of these transcriptional regulators. -- Abstract: Carnitine/acylcarnitine translocase (CACT) is a mitochondrial-membrane carrier proteins that mediates the transport of acylcarnitines into the mitochondrial matrix for their oxidation by the mitochondrial fatty acid-oxidation pathway. CACT deficiency causes a variety of pathological conditions, such as hypoketotic hypoglycemia, cardiac arrest, hepatomegaly, hepatic dysfunction and muscle weakness, and it can be fatal in newborns and infants. Here we report that expression of the Cact gene is induced in mouse skeletal muscle after 24 h of fasting. To gain insight into the control of Cact gene expression, we examine the transcriptional regulation of the mouse Cact gene. We show that the 5′-flanking region of this gene is transcriptionally active and contains a consensus sequence for the estrogen-related receptor (ERR), a member of the nuclear receptor family of transcription factors. This sequence binds ERRαin vivo and in vitro and is required for the activation of Cact expression by the peroxisome proliferator-activated receptor gamma coactivator (PGC)-1/ERR axis. We also demonstrate that XTC790, the inverse agonist of ERRα, specifically blocks Cact activation by PGC-1β in C2C12 cells.

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. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

ARA24/Ran enhances the androgen-dependent NH2- and COOH-terminal interaction of the androgen receptor

International Nuclear Information System (INIS)

Harada, Naoki; Ohmori, Yuji; Yamaji, Ryoichi; Higashimura, Yasuki; Okamoto, Kazuki; Isohashi, Fumihide; Nakano, Yoshihisa; Inui, Hiroshi

2008-01-01

The androgen receptor (AR) acts as an androgen-dependent transcription factor controlling the development of prostate tissue. Upon binding to androgen, AR undergoes a dynamic structural change leading to interaction between the NH 2 - and COOH-terminal regions of AR (N-C interaction). ARA24/Ran, which is a small GTPase, functions as an AR coactivator. Here, we report that ARA24/Ran enhances the N-C interaction of AR. The constitutively GTP- or GDP-bound form of ARA24/Ran repressed the AR N-C interaction. ARA24/Ran did not enhance the transcriptional activities of AR mutants that disrupt the N-C interaction. ARA24/Ran formed an endogenous protein complex with nuclear AR, but not cytoplasmic AR. Unlike SRC-1 with the positive activity for AR N-C interaction, ARA24/Ran did not enhance the transcriptional activity of the COOH-terminal domain-deleted AR mutant that is constitutively localized in the nucleus. These data demonstrate that ARA24/Ran increases AR transactivation by enhancing the AR N-C interaction in the nucleus

Phosphorylation inhibits DNA-binding of alternatively spliced aryl hydrocarbon receptor nuclear translocator

International Nuclear Information System (INIS)

Kewley, Robyn J.; Whitelaw, Murray L.

2005-01-01

The basic helix-loop-helix/PER-ARNT-SIM homology (bHLH/PAS) transcription factor ARNT (aryl hydrocarbon receptor nuclear translocator) is a key component of various pathways which induce the transcription of cytochrome P450 and hypoxia response genes. ARNT can be alternatively spliced to express Alt ARNT, containing an additional 15 amino acids immediately N-terminal to the DNA-binding basic region. Here, we show that ARNT and Alt ARNT proteins are differentially phosphorylated by protein kinase CKII in vitro. Phosphorylation had an inhibitory effect on DNA-binding to an E-box probe by Alt ARNT, but not ARNT, homodimers. This inhibitory phosphorylation occurs through Ser77. Moreover, a point mutant, Alt ARNT S77A, shows increased activity on an E-box reporter gene, consistent with Ser77 being a regulatory site in vivo. In contrast, DNA binding by an Alt ARNT/dioxin receptor heterodimer to the xenobiotic response element is not inhibited by phosphorylation with CKII, nor does Alt ARNT S77A behave differently from wild type Alt ARNT in the context of a dioxin receptor heterodimer

Xanthophylls increased HDLC level and nuclear factor PPARγ, RXRγ and RARα expression in hens and chicks.

Science.gov (United States)

Gao, Y-Y; Jin, L; Peng, H; Xu, L-H; Wang, Q-X; Ji, J; Wang, C-K; Bi, Y-Z

2018-02-01

This study was designed to investigate effects of xanthophylls on serum lipid profile (triglyceride, TG; cholesterol, CHO; high-density lipoprotein cholesterol, HDLC; and low-density lipoprotein cholesterol, LDLC) and nuclear factor (peroxisome proliferator-activated receptor gamma, PPARγ; PPAR gamma coactivator 1 alpha, PGC1α; retinoid X receptor gamma, RXRγ; and retinoic acid receptor alpha, RARα) gene expression of breeding hens and chicks. In experiment 1, 432 hens were divided into three groups and fed diets supplemented with 0 (as control group), 20 or 40 mg/kg xanthophylls. Blood was sampled at 7, 14, 21, 28 and 35 days of trial. Liver, duodenum, jejunum and ileum were sampled at 35 days of trial. Results showed that serum HDLC level of hens was increased after dietary 40 mg/kg xanthophyll addition for 21, 28 and 35 days, while serum TG, CHO and LDLC were not affected. Xanthophyll addition also increased PPARγ expression in jejunum, RXRγ expression in duodenum and jejunum, and RARα expression in liver and duodenum. Experiment 2 was a 2 × 2 factorial design. Male chicks hatched from 0 or 40 mg/kg xanthophyll diet of hens were fed diet containing either 0 or 40 mg/kg xanthophylls. Liver, duodenum, jejunum and ileum were sampled at 0, 7, 14 and 21 days after hatching. Blood samples were also collected at 21 days. Results showed that in ovo xanthophylls elevated PPARγ in duodenum and jejunum, and RXRγ and RARα in liver of chicks mainly within 1 week after hatching, while dietary xanthophylls increased serum HDLC level and PPARγ and RXRγ in liver from 2 weeks onwards. In conclusion, our research suggested xanthophylls can regulate serum lipid profile and nuclear factor expression in hens and chicks. © 2017 Blackwell Verlag GmbH.

Nuclear progesterone receptors are up-regulated by estrogens in neurons and radial glial progenitors in the brain of zebrafish.

Directory of Open Access Journals (Sweden)

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.

Ankle torque steadiness is related to muscle activation variability and coactivation in children with cerebral palsy

DEFF Research Database (Denmark)

Bandholm, Thomas; Rose, Martin Høyer; Sløk, Rikke

2009-01-01

The aims of this study were to: (1) investigate the significance of muscle activation variability and coactivation for the ability to perform steady submaximal ankle torque (torque steadiness) in healthy children and those with cerebral palsy (CP), and (2) assess ankle function during isometric...

The Drosophila DHR96 nuclear receptor binds cholesterol and regulates cholesterol homeostasis

OpenAIRE

Horner, Michael A.; Pardee, Keith; Liu, Suya; King-Jones, Kirst; Lajoie, Gilles; Edwards, Aled; Krause, Henry M.; Thummel, Carl S.

2009-01-01

Cholesterol homeostasis is required to maintain normal cellular function and avoid the deleterious effects of hypercholesterolemia. Here we show that the Drosophila DHR96 nuclear receptor binds cholesterol and is required for the coordinate transcriptional response of genes that are regulated by cholesterol and involved in cholesterol uptake, trafficking, and storage. DHR96 mutants die when grown on low levels of cholesterol and accumulate excess cholesterol when maintained on a high-choleste...

A novel acetylation cycle of transcription co-activator Yes-associated protein that is downstream of Hippo pathway is triggered in response to SN2 alkylating agents.

Science.gov (United States)

Hata, Shoji; Hirayama, Jun; Kajiho, Hiroaki; Nakagawa, Kentaro; Hata, Yutaka; Katada, Toshiaki; Furutani-Seiki, Makoto; Nishina, Hiroshi

2012-06-22

Yes-associated protein (YAP) is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes. Although cytoplasmic retention of YAP is known to be mediated by Hippo pathway-dependent phosphorylation, post-translational modifications that regulate YAP in the nucleus remain unclear. Here we report the discovery of a novel cycle of acetylation/deacetylation of nuclear YAP induced in response to S(N)2 alkylating agents. We show that after treatment of cells with the S(N)2 alkylating agent methyl methanesulfonate, YAP phosphorylation mediated by the Hippo pathway is markedly reduced, leading to nuclear translocation of YAP and its acetylation. This YAP acetylation occurs on specific and highly conserved C-terminal lysine residues and is mediated by the nuclear acetyltransferases CBP (CREB binding protein) and p300. Conversely, the nuclear deacetylase SIRT1 is responsible for YAP deacetylation. Intriguingly, we found that YAP acetylation is induced specifically by S(N)2 alkylating agents and not by other DNA-damaging stimuli. These results identify a novel YAP acetylation cycle that occurs in the nucleus downstream of the Hippo pathway. Intriguingly, our findings also indicate that YAP acetylation is involved in responses to a specific type of DNA damage.

A Novel Acetylation Cycle of Transcription Co-activator Yes-associated Protein That Is Downstream of Hippo Pathway Is Triggered in Response to SN2 Alkylating Agents*

Science.gov (United States)

Hata, Shoji; Hirayama, Jun; Kajiho, Hiroaki; Nakagawa, Kentaro; Hata, Yutaka; Katada, Toshiaki; Furutani-Seiki, Makoto; Nishina, Hiroshi

2012-01-01

Yes-associated protein (YAP) is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes. Although cytoplasmic retention of YAP is known to be mediated by Hippo pathway-dependent phosphorylation, post-translational modifications that regulate YAP in the nucleus remain unclear. Here we report the discovery of a novel cycle of acetylation/deacetylation of nuclear YAP induced in response to SN2 alkylating agents. We show that after treatment of cells with the SN2 alkylating agent methyl methanesulfonate, YAP phosphorylation mediated by the Hippo pathway is markedly reduced, leading to nuclear translocation of YAP and its acetylation. This YAP acetylation occurs on specific and highly conserved C-terminal lysine residues and is mediated by the nuclear acetyltransferases CBP (CREB binding protein) and p300. Conversely, the nuclear deacetylase SIRT1 is responsible for YAP deacetylation. Intriguingly, we found that YAP acetylation is induced specifically by SN2 alkylating agents and not by other DNA-damaging stimuli. These results identify a novel YAP acetylation cycle that occurs in the nucleus downstream of the Hippo pathway. Intriguingly, our findings also indicate that YAP acetylation is involved in responses to a specific type of DNA damage. PMID:22544757

Orphan nuclear receptor Nur77 participates in human apolipoprotein A5 gene expression

International Nuclear Information System (INIS)

Song, Kwang-Hoon

2010-01-01

The orphan nuclear receptor Nur77 (NR4A1) has been reported to play a crucial role in the modulation of diverse metabolic processes in liver. Here, we reported the identification of human apolipoprotein A5 (ApoA5), which implicated in lowering plasma triglyceride levels, as a novel target gene of Nur77. Nur77 induced the human ApoA5 promoter activity. Using 5'-deletion and mutagenesis of human ApoA5 promoter analysis and chromatin immunoprecipitation assays, it was shown that Nur77 directly regulated human ApoA5 gene expression by binding to a Nur77 response element (AAAGGTCA) located in the proximal human ApoA5 promoter region. In addition, we demonstrated that blocking of Nur77 transcriptional activity via overexpression of dominant negative Nur77 suppressed human ApoA5 promoter activity and mRNA expression in human hepatoma cells, HepG2. Taken together, our results demonstrated that Nur77 is a novel regulator of human ApoA5 gene expression and provide a new insight into the role of this orphan nuclear receptor in lipoprotein metabolism and triglyceride homeostasis.

Orphan nuclear receptor Nur77 participates in human apolipoprotein A5 gene expression

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Song, Kwang-Hoon, E-mail: ksong@kiom.re.kr [Korea Institute of Oriental Medicine, Daejeon 305-811 (Korea, Republic of)

2010-01-29

The orphan nuclear receptor Nur77 (NR4A1) has been reported to play a crucial role in the modulation of diverse metabolic processes in liver. Here, we reported the identification of human apolipoprotein A5 (ApoA5), which implicated in lowering plasma triglyceride levels, as a novel target gene of Nur77. Nur77 induced the human ApoA5 promoter activity. Using 5'-deletion and mutagenesis of human ApoA5 promoter analysis and chromatin immunoprecipitation assays, it was shown that Nur77 directly regulated human ApoA5 gene expression by binding to a Nur77 response element (AAAGGTCA) located in the proximal human ApoA5 promoter region. In addition, we demonstrated that blocking of Nur77 transcriptional activity via overexpression of dominant negative Nur77 suppressed human ApoA5 promoter activity and mRNA expression in human hepatoma cells, HepG2. Taken together, our results demonstrated that Nur77 is a novel regulator of human ApoA5 gene expression and provide a new insight into the role of this orphan nuclear receptor in lipoprotein metabolism and triglyceride homeostasis.

Training through gametherapy promotes coactivation of the pelvic floor and abdominal muscles in young women, nulliparous and continents

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Valeria Regina Silva

Full Text Available ABSTRACT Introduction and objectives: Several studies have been investigated co-activation can enhance the effectveness of PFM training protocols allowing preventive and therapeutic goals in pelvic floor dysfunctions. The objective of the present study was to investigate if an abdominal-pelvic protocol of training (APT using gametherapy would allow co-activation of PFM and transversus abdominis/oblique internal (TrA/OI muscles. Patients and methods: Twenty-five nulliparous, continent, young females, with median age 24.76 (±3.76 years were evaluated using digital palpation (DP of PFM and surface electromyography of PFM and TrA/OI simultaneously, during maximal voluntary contraction (MVC, alternating PFM and TrA/OI contraction requests. All women participated on a supervised program of APT using gametherapy, that included exercises of pelvic mobilization associated to contraction of TrA/OI muscles oriented by virtual games, for 30 minutes, three times a week, in a total of 10 sessions. Electromyographic data were processed and analyzed by ANOVA - analysis of variance. Results: When MVC of TrA/OI was solicited, it was observed simultaneous increase of electromyographic activity of PFM (p=0.001 following ATP. However, EMG activity did not change significantly during MVC of PFM. Conclusion: Training using gametherapy allowed better co-activation of pelvic floor muscles in response to contraction of TrA, in young nulliparous and continent women.

The Nuclear Receptor, Nor-1, Markedly Increases Type II Oxidative Muscle Fibers and Resistance to Fatigue

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Pearen, Michael A.; Eriksson, Natalie A.; Fitzsimmons, Rebecca L.; Goode, Joel M.; Martel, Nick; Andrikopoulos, Sofianos; Muscat, George E. O.

2012-01-01

Nuclear hormone receptors (NR) have been implicated as regulators of lipid and carbohydrate metabolism. The orphan NR4A subgroup has emerged as regulators of metabolic function. Targeted silencing of neuron-derived orphan receptor 1 (Nor-1)/NR4A3 in skeletal muscle cells suggested that this NR was necessary for oxidative metabolism in vitro. To investigate the in vivo role of Nor-1, we have developed a mouse model with preferential expression of activated Nor-1 in skeletal muscle. In skeletal...

Induction of the nuclear IκB protein IκB-ζ upon stimulation of B cell antigen receptor

International Nuclear Information System (INIS)

Hijioka, Kuniaki; Matsuo, Susumu; Eto-Kimura, Akiko; Takeshige, Koichiro; Muta, Tatsushi

2007-01-01

The nuclear IκB protein IκB-ζ is barely detectable in resting cells and is induced in macrophages and fibroblasts following stimulation of innate immunity via Toll-like receptors. The induced IκB-ζ associates with nuclear factor (NF)-κB in the nucleus and plays crucial roles in its transcriptional regulation. Here, we examined the induction of IκB-ζ in B lymphocytes, one of the major players in adaptive immunity. Upon crosslinking of the surface immunoglobulin complex, IκB-ζ mRNA was robustly induced in murine B-lymphoma cell line A20 cells. While the crosslinking activated NF-κB and induced its target gene, IκB-α, co-crosslinking of Fcγ receptor IIB to the surface immunoglobulin complex inhibited NF-κB activation and the induction of IκB-ζ and IκB-α, suggesting critical roles for NF-κB in the induction. These results indicate that IκB-ζ is also induced by stimulation of B cell antigen receptor, suggesting that IκB-ζ is involved in the regulation of adaptive immune responses

Differential modulation of expression of nuclear receptor mediated genes by tris(2-butoxyethyl) phosphate (TBOEP) on early life stages of zebrafish (Danio rerio)

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Ma, Zhiyuan, E-mail: zhiyuan_nju@163.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023 (China); Yu, Yijun, E-mail: yjun.yu@gmail.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023 (China); Tang, Song [School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK S7N 5B3 (Canada); Liu, Hongling, E-mail: hlliu@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023 (China); Su, Guanyong; Xie, Yuwei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023 (China); Giesy, John P. [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023 (China); Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3 (Canada); Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N 5B3 (Canada); Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region (Hong Kong); Hecker, Markus [School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK S7N 5B3 (Canada); Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3 (Canada); Yu, Hongxia [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023 (China)

2015-12-15

Highlights: • Effects of TBOEP on expression of genes of several nuclear hormone receptors and their relationship with adverse effect pathways in zebrafish. • TBOEP was neither an agonist nor antagonist of AR or AhR as determined by use of in vitro mammalian cell-based receptor transactivation assays. • Modulation of ER- and MR-dependent pathways allowed for development of feasible receptor-mediated, critical mechanisms of toxic action. - Abstract: As one substitute for phased-out brominated flame retardants (BFRs), tris(2-butoxyethyl) phosphate (TBOEP) is frequently detected in aquatic organisms. However, knowledge about endocrine disrupting mechanisms associated with nuclear receptors caused by TBOEP remained restricted to results from in vitro studies with mammalian cells. In the study, results of which are presented here, embryos/larvae of zebrafish (Danio rerio) were exposed to 0.02, 0.1 or 0.5 μM TBOEP to investigate expression of genes under control of several nuclear hormone receptors (estrogen receptors (ERs), androgen receptor (AR), thyroid hormone receptor alpha (TRα), mineralocorticoid receptor (MR), glucocorticoid receptor (GR), aryl hydrocarbon (AhR), peroxisome proliferator-activated receptor alpha (PPARα), and pregnane × receptor (P × R)) pathways at 120 hpf. Exposure to 0.5 μM TBOEP significantly (p < 0.05, one-way analysis of variance) up-regulated expression of estrogen receptors (ERs, er1, er2a, and er2b) genes and ER-associated genes (vtg4, vtg5, pgr, ncor, and ncoa3), indicating TBOEP modulates the ER pathway. In contrast, expression of most genes (mr, 11βhsd, ube2i,and adrb2b) associated with the mineralocorticoid receptor (MR) pathway were significantly down-regulated. Furthermore, in vitro mammalian cell-based (MDA-kb2 and H4IIE-luc) receptor transactivation assays, were also conducted to investigate possible agonistic or antagonistic effects on AR- and AhR-mediated pathways. In mammalian cells, none of these pathways were

A mutation in the receptor Methoprene-tolerant alters juvenile hormone response in insects and crustaceans.

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Miyakawa, Hitoshi; Toyota, Kenji; Hirakawa, Ikumi; Ogino, Yukiko; Miyagawa, Shinichi; Oda, Shigeto; Tatarazako, Norihisa; Miura, Toru; Colbourne, John K; Iguchi, Taisen

2013-01-01

Juvenile hormone is an essential regulator of major developmental and life history events in arthropods. Most of the insects use juvenile hormone III as the innate juvenile hormone ligand. By contrast, crustaceans use methyl farnesoate. Despite this difference that is tied to their deep evolutionary divergence, the process of this ligand transition is unknown. Here we show that a single amino-acid substitution in the receptor Methoprene-tolerant has an important role during evolution of the arthropod juvenile hormone pathway. Microcrustacea Daphnia pulex and D. magna share a juvenile hormone signal transduction pathway with insects, involving Methoprene-tolerant and steroid receptor coactivator proteins that form a heterodimer in response to various juvenoids. Juvenile hormone-binding pockets of the orthologous genes differ by only two amino acids, yet a single substitution within Daphnia Met enhances the receptor's responsiveness to juvenile hormone III. These results indicate that this mutation within an ancestral insect lineage contributed to the evolution of a juvenile hormone III receptor system.

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.

δ-opioid receptor and somatostatin receptor-4 heterodimerization: possible implications in modulation of pain associated signaling.

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Rishi K Somvanshi

Full Text Available Pain relief is the principal action of opioids. Somatostatin (SST, a growth hormone inhibitory peptide is also known to alleviate pain even in cases when opioids fail. Recent studies have shown that mice are prone to sustained pain and devoid of analgesic effect in the absence of somatostatin receptor 4 (SSTR4. In the present study, using brain slices, cultured neurons and HEK-293 cells, we showed that SSTR4 and δ-Opioid receptor (δOR exist in a heteromeric complex and function in synergistic manner. SSTR4 and δOR co-expressed in cortical/striatal brain regions and spinal cord. Using cultured neuronal cells, we describe the heterogeneous complex formation of SSTR4 and δOR at neuronal cell body and processes. Cotransfected cells display inhibition of cAMP/PKA and co-activation of SSTR4 and δOR oppose receptor trafficking induced by individual receptor activation. Furthermore, downstream signaling pathways either associated with withdrawal or pain relief are modulated synergistically with a predominant role of SSTR4. Inhibition of cAMP/PKA and activation of ERK1/2 are the possible cellular adaptations to prevent withdrawal induced by chronic morphine use. Our results reveal direct intra-membrane interaction between SSTR4 and δOR and provide insights for the molecular mechanism for the anti-nociceptive property of SST in combination with opioids as a potential therapeutic approach to avoid undesirable withdrawal symptoms.

A Molecular Modeling Study of the Hydroxyflutamide Resistance Mechanism Induced by Androgen Receptor Mutations

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Hong-Li Liu

2017-08-01

Full Text Available Hydroxyflutamide (HF, an active metabolite of the first generation antiandrogen flutamide, was used in clinic to treat prostate cancer targeting androgen receptor (AR. However, a drug resistance problem appears after about one year’s treatment. AR T877A is the first mutation that was found to cause a resistance problem. Then W741C_T877A and F876L_T877A mutations were also reported to cause resistance to HF, while W741C and F876L single mutations cannot. In this study, molecular dynamics (MD simulations combined with the molecular mechanics generalized Born surface area (MM-GBSA method have been carried out to analyze the interaction mechanism between HF and wild-type (WT/mutant ARs. The obtained results indicate that AR helix 12 (H12 plays a pivotal role in the resistance of HF. It can affect the coactivator binding site at the activation function 2 domain (AF2, surrounded by H3, H4, and H12. When H12 closes to the AR ligand-binding domain (LBD like a lid, the coactivator binding site can be formed to promote transcription. However, once H12 is opened to expose LBD, the coactivator binding site will be distorted, leading to invalid transcription. Moreover, per-residue free energy decomposition analyses indicate that N705, T877, and M895 are vital residues in the agonist/antagonist mechanism of HF.

The export receptor Crm1 forms a dimer to promote nuclear export of HIV RNA.

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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.

Antidepressant Imipramine Protects Bupivacaine-Induced Neurotoxicity in Dorsal Root Ganglion Neurons Through Coactivation of TrkA and TrkB.

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Guo, Jianrong; Wang, Huan; Tao, Qiang; Sun, Shiyu; Liu, Li; Zhang, Jianping; Yang, Dawei

2017-11-01

In our work, we used an in vitro culture model to investigate whether antidepressant imipramine (Ip) may protect bupivacaine (Bv)-induced neurotoxicity in mouse dorsal root ganglion (DRG). Adult mouse DRG was treated with 5 mM Bv in vitro to induce neurotoxicity. DRG was then pre-treated with Ip, prior to Bv, to examine its effects on protecting Bv-induced DRG apoptosis and neurite degeneration. Ip-induced dynamic changes in Trk receptors, including TrkA/B/C and phosphor (p-)TrkA/B/C, were examined by qPCR and Western blot. TrkA and TrkB were inhibited by siRNAs to further investigate their functional role in Ip- and Bv-treated DRG. Ip protected Bv-induced apoptosis and neurite loss in DRG. Ip did not alter TrkA/B/C expressions, whereas significantly augmented protein productions of p-TrkA and p-TrkB, but not p-TrkC. SiRNA-mediated TrkA or TrkB downregulation inhibited Trk receptors, and reduced p-TrkA and p-TrkB in DRG. TrkA or TrkB downregulation alone had no effect on Ip-induced protection in Bv-injured DRG. However, co-inhibition of TrkA and TrkB significantly ameliorated the protective effect of Ip on Bv-induced apoptosis and neurite loss in DRG. Imipramine protected bupivacaine-induced neurotoxicity in DRG, likely via the co-activation of TrkA and TrkB signaling pathways. J. Cell. Biochem. 118: 3960-3967, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

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.

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.

Basic Concepts in G-Protein-Coupled Receptor Homo- and Heterodimerization

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Rafael Franco

2007-01-01

Full Text Available Until recently, heptahelical G-protein-coupled receptors (GPCRs were considered to be expressed as monomers on the cell surface of neuronal and non-neuronal cells. It is now becoming evident that this view must be overtly changed since these receptors can form homodimers, heterodimers, and higher-order oligomers on the plasma membrane. Here we discuss some of the basics and some new concepts of receptor homo- and heteromerization. Dimers-oligomers modify pharmacology, trafficking, and signaling of receptors. First of all, GPCR dimers must be considered as the main molecules that are targeted by neurotransmitters or by drugs. Thus, binding data must be fitted to dimer-based models. In these models, it is considered that the conformational changes transmitted within the dimer molecule lead to cooperativity. Cooperativity must be taken into account in the binding of agonists-antagonists-drugs and also in the binding of the so-called allosteric modulators. Cooperativity results from the intramolecular cross-talk in the homodimer. As an intramolecular cross-talk in the heterodimer, the binding of one neurotransmitter to one receptor often affects the binding of the second neurotransmitter to the partner receptor. Coactivation of the two receptors in a heterodimer can change completely the signaling pathway triggered by the neurotransmitter as well as the trafficking of the receptors. Heterodimer-specific drugs or dual drugs able to activate the two receptors in the heterodimer simultaneously emerge as novel and promising drugs for a variety of central nervous system (CNS therapeutic applications.

Zipper-interacting protein kinase is involved in regulation of ubiquitination of the androgen receptor, thereby contributing to dynamic transcription complex assembly.

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Felten, A; Brinckmann, D; Landsberg, G; Scheidtmann, K H

2013-10-10

We have recently identified apoptosis-antagonizing transcription factor (AATF), tumor-susceptibility gene 101 (TSG101) and zipper-interacting protein kinase (ZIPK) as novel coactivators of the androgen receptor (AR). The mechanisms of coactivation remained obscure, however. Here we investigated the interplay and interdependence between these coactivators and the AR using the endogenous prostate specific antigen (PSA) gene as model for AR-target genes. Chromatin immunoprecipitation in combination with siRNA-mediated knockdown revealed that recruitment of AATF and ZIPK to the PSA enhancer was dependent on AR, whereas recruitment of TSG101 was dependent on AATF. Association of AR and its coactivators with the PSA enhancer or promoter occurred in cycles. Dissociation of AR-transcription complexes was due to degradation because inhibition of the proteasome system by MG132 caused accumulation of AR at enhancer/promoter elements. Moreover, inhibition of degradation strongly reduced transcription, indicating that continued and efficient transcription is based on initiation, degradation and reinitiation cycles. Interestingly, knockdown of ZIPK by siRNA had a similar effect as MG132, leading to reduced transcription but enhanced accumulation of AR at androgen-response elements. In addition, knockdown of ZIPK, as well as overexpression of a dominant-negative ZIPK mutant, diminished polyubiquitination of AR. Furthermore, ZIPK cooperated with the E3 ligase Mdm2 in AR-dependent transactivation, assembled into a single complex on chromatin and phosphorylated Mdm2 in vitro. These results suggest that ZIPK has a crucial role in regulation of ubiquitination and degradation of the AR, and hence promoter clearance and efficient transcription.

Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis

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Gomez-Ospina, Natalia; Potter, Carol J.; Xiao, Rui; Manickam, Kandamurugu; Kim, Mi-Sun; Kim, Kang Ho; Shneider, Benjamin L.; Picarsic, Jennifer L.; Jacobson, Theodora A.; Zhang, Jing; He, Weimin; Liu, Pengfei; Knisely, A. S.; Finegold, Milton J.; Muzny, Donna M.; Boerwinkle, Eric; Lupski, James R.; Plon, Sharon E.; Gibbs, Richard A.; Eng, Christine M.; Yang, Yaping; Washington, Gabriel C.; Porteus, Matthew H.; Berquist, William E.; Kambham, Neeraja; Singh, Ravinder J.; Xia, Fan; Enns, Gregory M.; Moore, David D.

2016-01-01

Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection. PMID:26888176

Inhibition of aryl hydrocarbon receptor-dependent transcription by resveratrol or kaempferol is independent of estrogen receptor α expression in human breast cancer cells

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MacPherson, Laura; Matthews, Jason

2016-01-01

Resveratrol and kaempferol are natural chemopreventative agents that are also aryl hydrocarbon receptor (AHR) antagonists and estrogen receptor (ER) agonists. In this study we evaluated the role of ERα in resveratrol- and kaempferol-mediated inhibition of AHR-dependent transcription. Kaempferol or resveratrol inhibited dioxin-induced cytochrome P450 1A1 (CYP1A1) and CYP1B1 expression levels and recruitment of AHR, ERα and co-activators to CYP1A1 and CYP1B1. Both phytochemicals induced the expression and recruitment of ERα to gene amplified in breast cancer 1 (GREB1). RNAi-mediated knockdown of ERα in T-47D cells did not affect the inhibitory action of either phytochemical on AHR activity. Both compounds also inhibited AHR-dependent transcription in ERα-negative MDA-MB-231 and BT-549 breast cancer cells. These data show that ERα does not contribute to the AHR-inhibitory activities of resveratrol and kaempferol. PMID:20846786

Dual roles for CoAA and its counterbalancing isoform CoAM in human kidney cell tumorigenesis

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Kang, Yun Kyoung; Schiff, Rachel; Ko, Lan; Wang, Tao; Tsai, Sophia Y.; Tsai, Ming-Jer; W. O’Malley, Bert

2008-01-01

Co-Activator Activator (CoAA) has been reported to be a coactivator that regulates steroid receptor-mediated transcription and alternative RNA splicing. Herein we show that CoAA is a dual-function coregulator that inhibits G1/S transition in human kidney cells and suppresses anchorage independent growth and xenograft tumor formation. Suppression occurs in part by downregulating c-myc and its downstream effectors ccnd1 and skp2, and causing accumulation of p27/Kip1 protein. In this cellular setting, CoAA directly represses the proto-oncogene, c-myc by recruiting HDAC3 protein and decreasing both the acetylation of histone H3 and the presence of RNA polymerase II on the c-myc promoter. Interestingly, a splicing isoform of CoAA, Coactivator Modulator (CoAM), antagonizes CoAA-induced G1/S transition and growth inhibition by negatively regulating the mRNA levels of the endogenous CoAA isoform. In addition, we found that expression of CoAA protein is significantly decreased in human renal cell carcinoma as compared to normal kidney. Our study presents evidence that CoAA is a potential tumor suppressor in renal carcinoma and that CoAM is a counterbalancing splice-isoform. This is so far the only example of a nuclear receptor coregulator involved in suppression of kidney cancer, and suggests potentially significant new roles for coregulators in renal cancer biology. PMID:18829545

Expression and Functional Pathway Analysis of Nuclear Receptor NR2F2 in Ovarian Cancer

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Hawkins, Shannon M.; Loomans, Holli A.; Wan, Ying-Wooi; Ghosh-Choudhury, Triparna; Coffey, Donna; Xiao, Weimin; Liu, Zhandong; Sangi-Haghpeykar, Haleh

2013-01-01

Context: Recent evidence implicates the orphan nuclear receptor, nuclear receptor subfamily 2, group F, member 2 (NR2F2; chicken ovalbumin upstream promoter-transcription factor II) as both a master regulator of angiogenesis and an oncogene in prostate and other human cancers. Objective: The objective of the study was to determine whether NR2F2 plays a role in ovarian cancer and dissect its potential mechanisms of action. Design, Setting, and Patients: We examined NR2F2 expression in healthy ovary and ovarian cancers using quantitative PCR and immunohistochemistry. NR2F2 expression was targeted in established ovarian cancer cell lines to assess the impact of dysregulated NR2F2 expression in the epithelial compartment of ovarian cancers. Results: Our results indicate that NR2F2 is robustly expressed in the stroma of healthy ovary with little or no expression in epithelia lining the ovarian surface, clefts, or crypts. This pattern of NR2F2 expression was markedly disrupted in ovarian cancers, in which decreased levels of stromal expression and ectopic epithelial expression were frequently observed. Ovarian cancers with the most disrupted patterns of NR2F2 were associated with significantly shorter disease-free interval by Kaplan-Meier analysis. Targeting NR2F2 expression in established ovarian cancer cell lines enhanced apoptosis and increased proliferation. In addition, we found that NR2F2 regulates the expression of NEK2, RAI14, and multiple other genes involved in the cell cycle, suggesting potential pathways by which dysregulated expression of NR2F2 impacts ovarian cancer. Conclusions: These results uncover novel roles for NR2F2 in ovarian cancer and point to a unique scenario in which a single nuclear receptor plays potentially distinct roles in the stromal and epithelial compartments of the same tissue. PMID:23690307

Identification of interacting proteins of retinoid-related orphan nuclear receptor gamma in HepG2 cells

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Ze-Min Huang1,#, Jun Wu2,#, Zheng-Cai Jia1, Yi Tian1, Jun Tang3, Yan Tang1, Ying Wang2, Yu-Zhang Wu1,* & Bing Ni1,*

2012-06-01

Full Text Available The retinoid-related orphan nuclear receptor gamma (RORγplays critical roles in regulation of development, immunity andmetabolism. As transcription factor usually forms a proteincomplex to function, thus capturing and dissecting of theRORγ protein complex will be helpful for exploring themechanisms underlying those functions. After construction ofthe recombinant tandem affinity purification (TAP plasmid,pMSCVpuro RORγ-CTAP(SG, the nuclear localization ofRORγ-CTAP(SG fusion protein was verified. Followingisolation of RORγ protein complex by TAP strategy, sevencandidate interacting proteins were identified. Finally, the heatshock protein 90 (HSP90 and receptor-interacting protein 140(RIP140 were confirmed to interplay with RORγ byco-immunoprecipitation. Interference of HSP90 or/and RIP140genes resulted in dramatically decreased expression ofCYP2C8 gene, the RORγ target gene. Data from this studydemonstrate that HSP90 and RIP140 proteins interact withRORγ protein in a complex format and function asco-activators in the RORγ-mediated regulatory processes ofHepG2 cells.

Deletion of the transcriptional coactivator PGC1α in skeletal muscles is associated with reduced expression of genes related to oxidative muscle function

International Nuclear Information System (INIS)

Hatazawa, Yukino; Minami, Kimiko; Yoshimura, Ryoji; Onishi, Takumi; Manio, Mark Christian; Inoue, Kazuo; Sawada, Naoki; Suzuki, Osamu; Miura, Shinji; Kamei, Yasutomi

2016-01-01

The expression of the transcriptional coactivator PGC1α is increased in skeletal muscles during exercise. Previously, we showed that increased PGC1α leads to prolonged exercise performance (the duration for which running can be continued) and, at the same time, increases the expression of branched-chain amino acid (BCAA) metabolism-related enzymes and genes that are involved in supplying substrates for the TCA cycle. We recently created mice with PGC1α knockout specifically in the skeletal muscles (PGC1α KO mice), which show decreased mitochondrial content. In this study, global gene expression (microarray) analysis was performed in the skeletal muscles of PGC1α KO mice compared with that of wild-type control mice. As a result, decreased expression of genes involved in the TCA cycle, oxidative phosphorylation, and BCAA metabolism were observed. Compared with previously obtained microarray data on PGC1α-overexpressing transgenic mice, each gene showed the completely opposite direction of expression change. Bioinformatic analysis of the promoter region of genes with decreased expression in PGC1α KO mice predicted the involvement of several transcription factors, including a nuclear receptor, ERR, in their regulation. As PGC1α KO microarray data in this study show opposing findings to the PGC1α transgenic data, a loss-of-function experiment, as well as a gain-of-function experiment, revealed PGC1α’s function in the oxidative energy metabolism of skeletal muscles. - Highlights: • Microarray analysis was performed in the skeletal muscle of PGC1α KO mice. • Expression of genes in the oxidative energy metabolism was decreased. • Bioinformatic analysis of promoter region of the genes predicted involvement of ERR. • PGC1α KO microarray data in this study show the mirror image of transgenic data.

Equivalent molecular mass of cytosolic and nuclear forms of Ah receptor from Hepa-1 cells determined by photoaffinity labeling with 2,3,7,8-[3H]tetrachlorodibenzo-p-dioxin

International Nuclear Information System (INIS)

Prokipcak, R.D.; Okey, A.B.

1990-01-01

The structure of the Ah receptor previously has been extensively characterized by reversible binding of the high affinity ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin. We report the use of [ 3 H]2,3,7,8-tetrachlorodibenzo-p-dioxin as a photoaffinity ligand for Ah receptor from the mouse hepatoma cell line Hepa-1c1c9. Both cytosolic and nuclear forms of Ah receptor could be specifically photoaffinity-labeled, which allowed determination of molecular mass for the two forms under denaturing conditions. After analysis by fluorography of polyacrylamide gels run in the presence of sodium dodecyl sulfate, molecular mass for the cytosolic form of Ah receptor was estimated at 92,000 +/- 4,300 and that for the nuclear form was estimated at 93,500 +/- 3,400. Receptor in mixture of cytosol and nuclear extract (each labeled separately with [ 3 H]2,3,7,8-tetrachlorodibenzo-p-dioxin) migrated as a single band. These results are consistent with the presence of a common ligand-binding subunit of identical molecular mass in both cytosolic and nuclear complexes

EFFECT OF ORTHOTIC SUBTALAR ALIGNMENT WITH CO-ACTIVATION EXERCISE FOR ALTERATION IN GAIT ENDURANCE IN A CHILD WITH CEREBRAL PALSYSINGLE CASE STUDY

Directory of Open Access Journals (Sweden)

K. Vadivelan

2016-10-01

Full Text Available Background: Energy cost of walking is two times higher in children with cerebral palsy when compared with normal children; this may be due to gait abnormalities.There is a negative influence on physical activity and early onsets of fatigue in activities of daily living are evident in cerebral palsy children and the reason for this is increase in energy cost of walking. Therefore, the treatment techniques which targets on correction of gait abnormalities and Energy conservation during walking are important to maintain orimprove independent functioning.The aim is to find out the effects of using Supra Malleolar Orthosis (SMO along with co-activation exercise in the increase of gait endurance and also to encourage independent skills and abilities in cerebral palsy child. Methods: A 14 years child with spastic hemiplegic cerebral palsy was treated with custom made supra malleolar orthotic which was designed with an orthotic support followed with specific exercises, co-activating dorsiflexors and plantar flexors actively and with assistance. The subject was made to do the co-activation exercises 3 days per week for 8 weeks. Step length, stride length, cadence, navicular drop test, medial arch height and calcaneal eversion were measured before starting the treatment and at the end of 8th week. Results: the results of treatment shows that there is an improvement in 2 minutes’ walk test from 7(pre-test to 13, step length from 22 (pre-test to 32,stride length from 36(pre-test to 47,cadence from 39 (pretest to 37 after the use of Supra Malleolar Orthosis (SMO and a co-activation exercises intervention. There was a clear and significant improvement noted in navicular drop test, medial arch height and calcaneal eversion after a period of 8 weeks use of orthosis and exercise intervention when compared with pre-test value. Conclusion: Orthotic subtalar alignment with co-acticvation exercises for alteration in gait endurance in a child is showing

A unique nuclear receptor direct repeat 17 (DR17) is present within the upstream region of Schistosoma mansoni female-specific p14 gene

International Nuclear Information System (INIS)

Fantappie, Marcelo Rosado; Furtado, Daniel Rodrigues; Rumjanek, Franklin David; LoVerde, Philip T.

2008-01-01

The eggs produced by sexually mature female Schistosma mansoni are responsible for the pathogenesis of the disease. The eggshell precursor gene p14 is expressed only in the vitelline cells of sexually mature female worms in response to a yet unidentified male stimulus. Herein, we report the identification of a novel nuclear receptor response element in the upstream region of the p14 gene. This element contains the canonical hexameric DNA core motif, 5'-PuGGTCA, composed of an atypically spaced direct repeat (DR17). Schistosome nuclear receptors SmRXR1 and SmNR1 specifically bound to the p14-DR17 element as a heterodimer. SmRXR1, but not SmNR1, bound to the motif as a monomer. Introduction of mutations in the TCA core sequence completely abolished the binding by SmRXR1/SmNR1 heterodimer. This finding supports our hypothesis that the expression of Schistosoma mansonip14 gene is regulated through the nuclear receptor signaling pathway

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.

Nitric oxide coordinates metabolism, growth, and development via the nuclear receptor E75

OpenAIRE

Cáceres, Lucía; Necakov, Aleksandar S.; Schwartz, Carol; Kimber, Sandra; Roberts, Ian J.H.; Krause, Henry M.

2011-01-01

Nitric oxide gas acts as a short-range signaling molecule in a vast array of important physiological processes, many of which include major changes in gene expression. How these genomic responses are induced, however, is poorly understood. Here, using genetic and chemical manipulations, we show that nitric oxide is produced in the Drosophila prothoracic gland, where it acts via the nuclear receptor ecdysone-induced protein 75 (E75), reversing its ability to interfere with its heterodimer part...

The Nucleosome Assembly Activity of NAP1 Is Enhanced by Alien▿

OpenAIRE

Eckey, Maren; Hong, Wei; Papaioannou, Maria; Baniahmad, Aria

2007-01-01

The assembly of nucleosomes into chromatin is essential for the compaction of DNA and inactivation of the DNA template to modulate and repress gene expression. The nucleosome assembly protein 1, NAP1, assembles nucleosomes independent of DNA synthesis and was shown to enhance coactivator-mediated gene expression, suggesting a role for NAP1 in transcriptional regulation. Here, we show that Alien, known to harbor characteristics of a corepressor of nuclear hormone receptors such as of the vitam...

CINPA1 Is an Inhibitor of Constitutive Androstane Receptor That Does Not Activate Pregnane X Receptor

Science.gov (United States)

Cherian, Milu T; Lin, Wenwei; Wu, Jing

2015-01-01

Constitutive androstane receptor (CAR) and pregnane X receptor (PXR) are xenobiotic sensors that enhance the detoxification and elimination of xenobiotics and endobiotics by modulating the expression of genes encoding drug-metabolizing enzymes and transporters. Elevated levels of drug-metabolizing enzymes and efflux transporters, resulting from CAR activation in various cancers, promote the elimination of chemotherapeutic agents, leading to reduced therapeutic effectiveness and acquired drug resistance. CAR inhibitors, in combination with existing chemotherapeutics, could therefore be used to attenuate multidrug resistance in cancers. Interestingly, all previously reported CAR inverse-agonists are also activators of PXR, rendering them mechanistically counterproductive in tissues where both these xenobiotic receptors are present and active. We used a directed high-throughput screening approach, followed by subsequent mechanistic studies, to identify novel, potent, and specific small-molecule CAR inhibitors that do not activate PXR. We describe here one such inhibitor, CINPA1 (CAR inhibitor not PXR activator 1), capable of reducing CAR-mediated transcription with an IC50 of ∼70 nM. CINPA1 1) is a specific xenobiotic receptor inhibitor and has no cytotoxic effects up to 30 µM; 2) inhibits CAR-mediated gene expression in primary human hepatocytes, where CAR is endogenously expressed; 3) does not alter the protein levels or subcellular localization of CAR; 4) increases corepressor and reduces coactivator interaction with the CAR ligand-binding domain in mammalian two-hybrid assays; and 5) disrupts CAR binding to the promoter regions of target genes in chromatin immunoprecipitation assays. CINPA1 could be used as a novel molecular tool for understanding CAR function. PMID:25762023

Interleukin-10 increases reverse cholesterol transport in macrophages through its bidirectional interaction with liver X receptor α

International Nuclear Information System (INIS)

Halvorsen, Bente; Holm, Sverre; Yndestad, Arne; Scholz, Hanne; Sagen, Ellen Lund; Nebb, Hilde; Holven, Kirsten B.; Dahl, Tuva B.; Aukrust, Pål

2014-01-01

Highlights: • IL-10 promotes reverse cholesterol efflux from lipid loaded macrophages. • IL-10 increases the expression of ABCA-1 and ABCG-1. • IL-10 exhibits cross-talk with the nuclear receptor LXRα. - Abstract: Interleukin (IL)-10 is a prototypical anti-inflammatory cytokine that has been shown to attenuate atherosclerosis development. In addition to its anti-inflammatory properties, the anti-atherogenic effect of IL-10 has recently also been suggested to reflect a complex effect of IL-10 on lipid metabolism in macrophages. In the present study we examined the effects of IL-10 on cholesterol efflux mechanism in lipid-loaded THP-1 macrophages. Our main findings were: (i) IL-10 significantly enhanced cholesterol efflux induced by fetal-calf serum, high-density lipoprotein (HDL) 2 and apolipoprotein A-1. (ii) The IL-10-mediated effects on cholesterol efflux were accompanied by an increased IL-10-mediated expression of the ATP-binding cassette transporters ABCA1 and ABCG1, that was further enhanced when the cells were co-activated with the liver X receptor (LXR)α agonist (22R)-hydroxycholesterol. (iii) The effect of LXRα activation on the IL-10-mediated effects on the ATP-binding cassette transporters seems to include enhancing effects on the IL-10 receptor 1 (IL10R1) expression and interaction with STAT-3 signaling. (iv) These enhancing effects on ABCA1 and ABCG1 was not seen when the cells were stimulated with the IL-10 family members IL-22 and IL-24. This study suggests that the anti-atherogenic properties of IL-10 may include enhancing effects on cholesterol efflux mechanism that involves cross-talk with LXRα activation

Interleukin-10 increases reverse cholesterol transport in macrophages through its bidirectional interaction with liver X receptor α

Energy Technology Data Exchange (ETDEWEB)

Halvorsen, Bente, E-mail: Bente.Halvorsen@rr-research.no [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); K.G. Jebsen Inflammation Research Center, University of Oslo, Oslo (Norway); Holm, Sverre [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Yndestad, Arne [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); K.G. Jebsen Inflammation Research Center, University of Oslo, Oslo (Norway); Scholz, Hanne [Section for Transplantation, Institute for Surgical Research, Oslo University Hospital Rikshospitalet, Oslo (Norway); Sagen, Ellen Lund [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Nebb, Hilde [Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); Holven, Kirsten B. [Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Oslo (Norway); Dahl, Tuva B. [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); Aukrust, Pål [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); K.G. Jebsen Inflammation Research Center, University of Oslo, Oslo (Norway)

2014-08-08

Highlights: • IL-10 promotes reverse cholesterol efflux from lipid loaded macrophages. • IL-10 increases the expression of ABCA-1 and ABCG-1. • IL-10 exhibits cross-talk with the nuclear receptor LXRα. - Abstract: Interleukin (IL)-10 is a prototypical anti-inflammatory cytokine that has been shown to attenuate atherosclerosis development. In addition to its anti-inflammatory properties, the anti-atherogenic effect of IL-10 has recently also been suggested to reflect a complex effect of IL-10 on lipid metabolism in macrophages. In the present study we examined the effects of IL-10 on cholesterol efflux mechanism in lipid-loaded THP-1 macrophages. Our main findings were: (i) IL-10 significantly enhanced cholesterol efflux induced by fetal-calf serum, high-density lipoprotein (HDL){sub 2} and apolipoprotein A-1. (ii) The IL-10-mediated effects on cholesterol efflux were accompanied by an increased IL-10-mediated expression of the ATP-binding cassette transporters ABCA1 and ABCG1, that was further enhanced when the cells were co-activated with the liver X receptor (LXR)α agonist (22R)-hydroxycholesterol. (iii) The effect of LXRα activation on the IL-10-mediated effects on the ATP-binding cassette transporters seems to include enhancing effects on the IL-10 receptor 1 (IL10R1) expression and interaction with STAT-3 signaling. (iv) These enhancing effects on ABCA1 and ABCG1 was not seen when the cells were stimulated with the IL-10 family members IL-22 and IL-24. This study suggests that the anti-atherogenic properties of IL-10 may include enhancing effects on cholesterol efflux mechanism that involves cross-talk with LXRα activation.

A Transcriptional Regulatory Network Containing Nuclear Receptors and Long Noncoding RNAs Controls Basal and Drug-Induced Expression of Cytochrome P450s in HepaRG Cells.

Science.gov (United States)

Chen, Liming; Bao, Yifan; Piekos, Stephanie C; Zhu, Kexin; Zhang, Lirong; Zhong, Xiao-Bo

2018-07-01

Cytochrome P450 (P450) enzymes are responsible for metabolizing drugs. Expression of P450s can directly affect drug metabolism, resulting in various outcomes in therapeutic efficacy and adverse effects. Several nuclear receptors are transcription factors that can regulate expression of P450s at both basal and drug-induced levels. Some long noncoding RNAs (lncRNAs) near a transcription factor are found to participate in the regulatory functions of the transcription factors. The aim of this study is to determine whether there is a transcriptional regulatory network containing nuclear receptors and lncRNAs controlling both basal and drug-induced expression of P450s in HepaRG cells. Small interfering RNAs or small hairpin RNAs were applied to knock down four nuclear receptors [hepatocyte nuclear factor 1 α (HNF1 α ), hepatocyte nuclear factor 4 α (HNF4 α ), pregnane X receptor (PXR), and constitutive androstane receptor (CAR)] as well as two lncRNAs [HNF1 α antisense RNA 1 (HNF1 α -AS1) and HNF4 α antisense RNA 1 (HNF4 α -AS1)] in HepaRG cells with or without treatment of phenobarbital or rifampicin. Expression of eight P450 enzymes was examined in both basal and drug-induced levels. CAR and PXR mainly regulated expression of specific P450s. HNF1 α and HNF4 α affected expression of a wide range of P450s as well as other transcription factors. HNF1 α and HNF4 α controlled the expression of their neighborhood lncRNAs, HNF1 α -AS1 and HNF4 α -AS1, respectively. HNF1 α -AS1 and HNF4 α -AS1 was also involved in the regulation of P450s and transcription factors in diverse manners. Altogether, our study concludes that a transcription regulatory network containing the nuclear receptors and lncRNAs controls both basal and drug-induced expression of P450s in HepaRG cells. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Low concentrations of bisphenol a suppress thyroid hormone receptor transcription through a nongenomic mechanism

International Nuclear Information System (INIS)

Sheng, Zhi-Guo; Tang, Yuan; Liu, Yu-Xiang; Yuan, Ye; Zhao, Bao-Quan; Chao, Xi-Juan; Zhu, Ben-Zhan

2012-01-01

Bisphenol (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Various rodent and in vitro studies have shown that thyroid hormone (TH) function can be impaired by BPA. However, it is still unknown if low concentrations of BPA can suppress the thyroid hormone receptor (TR) transcription. The present study aims to investigate the possible suppressing effects of low concentrations of BPA on TR transcription and the involved mechanism(s) in CV-1 cells derived from cercopithecus aethiops monkey kidneys. Using gene reporter assays, BPA at concentrations as low as 10 −9 M suppresses TR or steroid receptor coactivator-1(SRC-1)-enhanced TR transcription, but not reducing TR/SRC-1 interaction in mammalian two-hybrid and glutathione S-transferase pull-down studies. It has been further shown that both nuclear receptor co-repressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) are recruited to the TR-β1 by BPA in the presence of physiologic concentrations of T3 or T4. However, the overexpression of β3 integrin or c-Src significantly reduces BPA-induced recruitment of N-CoR/SMRT to TR or suppression of TR transcription. Furthermore, BPA inhibits the T3/T4-mediated interassociation of the β3 integrin/c-Src/MAPK/TR-β1 pathways by the co-immunoprecipitation. These results indicate that low concentrations of BPA suppress the TR transcription by disrupting physiologic concentrations of T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways, followed by recruiting N-CoR/SMRT to TR-β1, providing a novel insight regarding the TH disruption effects of low concentration BPA. -- Highlights: ► Environmentally relevant concentrations of BPA suppress TR transcription. ► BPA recruits the N-CoR/SMRT to TR under the physiologic concentrations of T3/T4. ► BPA disrupts T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways.

Low concentrations of bisphenol a suppress thyroid hormone receptor transcription through a nongenomic mechanism

Energy Technology Data Exchange (ETDEWEB)

Sheng, Zhi-Guo [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Tang, Yuan [Department of Pharmaceutics, College of Pharmacy, Third Military Medical University, 30 Yanzheng Street, Chongqing 400038 (China); Liu, Yu-Xiang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Yuan, Ye; Zhao, Bao-Quan [Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850 (China); Chao, Xi-Juan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Zhu, Ben-Zhan, E-mail: bzhu@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)

2012-02-15

Bisphenol (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Various rodent and in vitro studies have shown that thyroid hormone (TH) function can be impaired by BPA. However, it is still unknown if low concentrations of BPA can suppress the thyroid hormone receptor (TR) transcription. The present study aims to investigate the possible suppressing effects of low concentrations of BPA on TR transcription and the involved mechanism(s) in CV-1 cells derived from cercopithecus aethiops monkey kidneys. Using gene reporter assays, BPA at concentrations as low as 10{sup −9} M suppresses TR or steroid receptor coactivator-1(SRC-1)-enhanced TR transcription, but not reducing TR/SRC-1 interaction in mammalian two-hybrid and glutathione S-transferase pull-down studies. It has been further shown that both nuclear receptor co-repressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) are recruited to the TR-β1 by BPA in the presence of physiologic concentrations of T3 or T4. However, the overexpression of β3 integrin or c-Src significantly reduces BPA-induced recruitment of N-CoR/SMRT to TR or suppression of TR transcription. Furthermore, BPA inhibits the T3/T4-mediated interassociation of the β3 integrin/c-Src/MAPK/TR-β1 pathways by the co-immunoprecipitation. These results indicate that low concentrations of BPA suppress the TR transcription by disrupting physiologic concentrations of T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways, followed by recruiting N-CoR/SMRT to TR-β1, providing a novel insight regarding the TH disruption effects of low concentration BPA. -- Highlights: ► Environmentally relevant concentrations of BPA suppress TR transcription. ► BPA recruits the N-CoR/SMRT to TR under the physiologic concentrations of T3/T4. ► BPA disrupts T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways.

Transcriptional targets shared by estrogen receptor- related receptors (ERRs) and estrogen receptor (ER) alpha, but not by ERbeta.

Science.gov (United States)

Vanacker, J M; Pettersson, K; Gustafsson, J A; Laudet, V

1999-01-01

The physiological activities of estrogens are thought to be mediated by specific nuclear receptors, ERalpha and ERbeta. However, certain tissues, such as the bone, that are highly responsive to estrogens only express a low level of these receptors. Starting from this apparent contradiction, we have evaluated the potentials of two related receptors ERRalpha and ERRbeta to intervene in estrogen signaling. ERalpha, ERRalpha and ERRbeta bind to and activate transcription through both the classical estrogen response element (ERE) and the SF-1 response element (SFRE). In contrast, ERbeta DNA-binding and transcriptional activity is restricted to the ERE. Accordingly, the osteopontin gene promoter is stimulated through SFRE sequences, by ERRalpha as well as by ERalpha, but not by ERbeta. Analysis of the cross-talk within the ER/ERR subgroup of nuclear receptors thus revealed common targets but also functional differences between the two ERs. PMID:10428965

A live zebrafish-based screening system for human nuclear receptor ligand and cofactor discovery.

Science.gov (United States)

Tiefenbach, Jens; Moll, Pamela R; Nelson, Meryl R; Hu, Chun; Baev, Lilia; Kislinger, Thomas; Krause, Henry M

2010-03-22

Nuclear receptors (NRs) belong to a superfamily of transcription factors that regulate numerous homeostatic, metabolic and reproductive processes. Taken together with their modulation by small lipophilic molecules, they also represent an important and successful class of drug targets. Although many NRs have been targeted successfully, the majority have not, and one third are still orphans. Here we report the development of an in vivo GFP-based reporter system suitable for monitoring NR activities in all cells and tissues using live zebrafish (Danio rerio). The human NR fusion proteins used also contain a new affinity tag cassette allowing the purification of receptors with bound molecules from responsive tissues. We show that these constructs 1) respond as expected to endogenous zebrafish hormones and cofactors, 2) facilitate efficient receptor and cofactor purification, 3) respond robustly to NR hormones and drugs and 4) yield readily quantifiable signals. Transgenic lines representing the majority of human NRs have been established and are available for the investigation of tissue- and isoform-specific ligands and cofactors.

A live zebrafish-based screening system for human nuclear receptor ligand and cofactor discovery.

Directory of Open Access Journals (Sweden)

Jens Tiefenbach

2010-03-01

Full Text Available Nuclear receptors (NRs belong to a superfamily of transcription factors that regulate numerous homeostatic, metabolic and reproductive processes. Taken together with their modulation by small lipophilic molecules, they also represent an important and successful class of drug targets. Although many NRs have been targeted successfully, the majority have not, and one third are still orphans. Here we report the development of an in vivo GFP-based reporter system suitable for monitoring NR activities in all cells and tissues using live zebrafish (Danio rerio. The human NR fusion proteins used also contain a new affinity tag cassette allowing the purification of receptors with bound molecules from responsive tissues. We show that these constructs 1 respond as expected to endogenous zebrafish hormones and cofactors, 2 facilitate efficient receptor and cofactor purification, 3 respond robustly to NR hormones and drugs and 4 yield readily quantifiable signals. Transgenic lines representing the majority of human NRs have been established and are available for the investigation of tissue- and isoform-specific ligands and cofactors.

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.

Botanical compounds and their regulation of nuclear receptor action: the case of traditional Chinese medicine.

Science.gov (United States)

Li, Ling; Bonneton, François; Chen, Xiao Yong; Laudet, Vincent

2015-02-05

Nuclear receptors (NRs) are major pharmacological targets that allow an access to the mechanisms controlling gene regulation. As such, some NRs were identified as biological targets of active compounds contained in herbal remedies found in traditional medicines. We aim here to review this expanding literature by focusing on the informative articles regarding the mechanisms of action of traditional Chinese medicines (TCMs). We exemplified well-characterized TCM action mediated by NR such as steroid receptors (ER, GR, AR), metabolic receptors (PPAR, LXR, FXR, PXR, CAR) and RXR. We also provided, when possible, examples from other traditional medicines. From these, we draw a parallel between TCMs and phytoestrogens or endocrine disrupting chemicals also acting via NR. We define common principle of action and highlight the potential and limits of those compounds. TCMs, by finely tuning physiological reactions in positive and negative manners, could act, in a subtle but efficient way, on NR sensors and their transcriptional network. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

[The molecular mechanisms and morphological manifestations of leiomyoma reduction induced by selective progesterone receptor modulators].

Science.gov (United States)

Demura, T A; Revazova, Z V; Kogan, E A; Adamyan, L V

to investigate the molecular mechanisms and morphological substrate of reduced uterine leiomyoma in patients receiving the selective progesterone receptor modulator (SPRM) ulipristal acetate for 3 months, by estimating the immunohistochemical expression of the markers steroid receptor coactivator 1 (SRC-1), nuclear receptor corepressor 1 (NCoR-1), ER, PgR, Ki-67, p16, TGF-β, and VEGF in tumor tissue. The investigation enrolled 75 women with uterine leiomyoma, menorrhagias, and anemia. Group 1 included 40 patients who were treated with ulipristal for 3 months, followed by laparoscopic myomectomy. Group 2 consisted of 35 patients who underwent surgery without previous preparation. The intra- and postoperative parameters and molecular and morphological changes in the myomatous nodules were comparatively analyzed in both groups. After 3 months of therapy initiation, menorrhagia completely ceased, myomatous nodules decreased in size (pleiomyoma reduction was leiomyocyte apoptosis and dystrophy, tumor stroma sclerosis and hyalinosis with diminished Ki-67 expression and elevated p16 in the smooth muscle cells, trophic nodular tissue disorders exhibited by vascular wall sclerosis and lower VEGF and TGF-β expression, and leiomyocyte hormonal reception dysregulation that made itself evident through the reduced expression of SRC-1 with the unchanged expression of PR and ER and the maintained level of NCoR-1. The molecular mechanisms of tumor reduction involved the reduced Ki-67 expression and elevated p16, lower VEGF and TGF-β, diminished SRC-1 expression with the maintained level of PR, ER, and NCoR-1. Overall, this is suggestive of enhanced apoptosis and reduced leiomyoma proliferation and angiogenesis induced by SPRM and indicative of the expediency of using ulipristal acetate as a preoperative agent for organ-sparing surgery in reproductive-aged patients with uterine myoma, menorrhagias, and anemia.

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.

Asymmetry and Thigh Muscle Coactivity in Fatigued Anterior Cruciate Ligament-Reconstructed Elite Skiers

DEFF Research Database (Denmark)

Jordan, Matthew J; Aagaard, Per; Herzog, Walter

2017-01-01

PURPOSE: The acute effects of fatigue on functional interlimb asymmetry and quadriceps/hamstring muscle activity levels, including preparatory coactivation during squat jump takeoff and landing, were evaluated in elite alpine ski racers with/without anterior cruciate ligament reconstruction (ACLR......). METHODS: Twenty-two elite ski racers (ACLR, n = 11; control, n = 11) performed an 80-s repeated squat jump test (jump test) on a dual force plate system with simultaneous EMG recordings in vastus lateralis, vastus medialis, semitendinosus, and biceps femoris. Asymmetry index (AI) and jump height of body...

Effects of cypermethrin on the ligand-independent interaction between androgen receptor and steroid receptor coactivator-1

International Nuclear Information System (INIS)

Pan, Chen; Liu, Ya-Peng; Li, Yan-Fang; Hu, Jin-Xia; Zhang, Jin-Peng; Wang, Hong-Mei; Li, Jing; Xu, Li-Chun

2012-01-01

The pyrethroid insecticide, cypermethrin has been considered as an environmental anti-androgen by interfering with the androgen receptor (AR) transactivation. In order to clarify the effects of cypermethrin on the ligand-independent interaction between the AR and SRC-1, the mammalian two-hybrid assay has been developed in the study. The AR N-terminal domain 1–660 amino acid residues were subcloned into the plasmid pVP16 to construct the vector pVP16-ARNTD. The SRC-1 C-terminal domain 989–1240 amino acid residues were subcloned into the plasmid pM to construct the vector pM-SRC-1. The fusion vectors pVP16-ARNTD, pM-SRC-1 and the pG5CAT Reporter Vector were cotransfected into the CV-1 cells. The AR AF1 interacted with SRC-1 in the absence of exogenous ligand 5α-dihydrotestosterone (DHT). Furthermore, DHT did not enhance the interaction between AR AF-1 and SRC-1 at the concentrations from 10 −10 M to 10 −8 M. Cypermethrin inhibited the interaction between the AR AF1 and SRC-1, and the significant reduction was detected at the concentration of 10 −5 M. It is suggested that the interaction between the AR AF1 and SRC-1 is ligand-independent. Cypermethrin inhibits AR activity by disrupting the ligand-independent AR–SRC-1 interaction.

Control of mitochondrial metabolism and systemic energy homeostasis by microRNAs 378 and 378*.

Science.gov (United States)

Carrer, Michele; Liu, Ning; Grueter, Chad E; Williams, Andrew H; Frisard, Madlyn I; Hulver, Matthew W; Bassel-Duby, Rhonda; Olson, Eric N

2012-09-18

Obesity and metabolic syndrome are associated with mitochondrial dysfunction and deranged regulation of metabolic genes. Peroxisome proliferator-activated receptor γ coactivator 1β (PGC-1β) is a transcriptional coactivator that regulates metabolism and mitochondrial biogenesis through stimulation of nuclear hormone receptors and other transcription factors. We report that the PGC-1β gene encodes two microRNAs (miRNAs), miR-378 and miR-378*, which counterbalance the metabolic actions of PGC-1β. Mice genetically lacking miR-378 and miR-378* are resistant to high-fat diet-induced obesity and exhibit enhanced mitochondrial fatty acid metabolism and elevated oxidative capacity of insulin-target tissues. Among the many targets of these miRNAs, carnitine O-acetyltransferase, a mitochondrial enzyme involved in fatty acid metabolism, and MED13, a component of the Mediator complex that controls nuclear hormone receptor activity, are repressed by miR-378 and miR-378*, respectively, and are elevated in the livers of miR-378/378* KO mice. Consistent with these targets as contributors to the metabolic actions of miR-378 and miR-378*, previous studies have implicated carnitine O-acetyltransferase and MED13 in metabolic syndrome and obesity. Our findings identify miR-378 and miR-378* as integral components of a regulatory circuit that functions under conditions of metabolic stress to control systemic energy homeostasis and the overall oxidative capacity of insulin target tissues. Thus, these miRNAs provide potential targets for pharmacologic intervention in obesity and metabolic syndrome.

Structure and expression of two nuclear receptor genes in marsupials: insights into the evolution of the antisense overlap between the α-thyroid hormone receptor and Rev-erbα

Directory of Open Access Journals (Sweden)

Brown M Scott

2010-12-01

Full Text Available Abstract Background Alternative processing of α-thyroid hormone receptor (TRα, NR1A1 mRNAs gives rise to two functionally antagonistic nuclear receptors: TRα1, the α-type receptor, and TRα2, a non-hormone binding variant that is found only in mammals. TRα2 shares an unusual antisense coding overlap with mRNA for Rev-erbα (NR1D1, another nuclear receptor protein. In this study we examine the structure and expression of these genes in the gray short-tailed opossum, Monodelphis domestica, in comparison with that of eutherian mammals and three other marsupial species, Didelphis virginiana, Potorous tridactylus and Macropus eugenii, in order to understand the evolution and regulatory role of this antisense overlap. Results The sequence, expression and genomic organization of mRNAs encoding TRα1 and Rev-erbα are very similar in the opossum and eutherian mammals. However, the sequence corresponding to the TRα2 coding region appears truncated by almost 100 amino acids. While expression of TRα1 and Rev-erbα was readily detected in all tissues of M. domestica ages 0 days to 18 weeks, TRα2 mRNA was not detected in any tissue or stage examined. These results contrast with the widespread and abundant expression of TRα2 in rodents and other eutherian mammals. To examine requirements for alternative splicing of TRα mRNAs, a series of chimeric minigenes was constructed. Results show that the opossum TRα2-specific 5' splice site sequence is fully competent for splicing but the sequence homologous to the TRα2 3' splice site is not, even though the marsupial sequences are remarkably similar to core splice site elements in rat. Conclusions Our results strongly suggest that the variant nuclear receptor isoform, TRα2, is not expressed in marsupials and that the antisense overlap between TRα and Rev-erbα thus is unique to eutherian mammals. Further investigation of the TRα and Rev-erbα genes in marsupial and eutherian species promises to yield

Structure and expression of two nuclear receptor genes in marsupials: insights into the evolution of the antisense overlap between the α-thyroid hormone receptor and Rev-erbα

Science.gov (United States)

2010-01-01

Background Alternative processing of α-thyroid hormone receptor (TRα, NR1A1) mRNAs gives rise to two functionally antagonistic nuclear receptors: TRα1, the α-type receptor, and TRα2, a non-hormone binding variant that is found only in mammals. TRα2 shares an unusual antisense coding overlap with mRNA for Rev-erbα (NR1D1), another nuclear receptor protein. In this study we examine the structure and expression of these genes in the gray short-tailed opossum, Monodelphis domestica, in comparison with that of eutherian mammals and three other marsupial species, Didelphis virginiana, Potorous tridactylus and Macropus eugenii, in order to understand the evolution and regulatory role of this antisense overlap. Results The sequence, expression and genomic organization of mRNAs encoding TRα1 and Rev-erbα are very similar in the opossum and eutherian mammals. However, the sequence corresponding to the TRα2 coding region appears truncated by almost 100 amino acids. While expression of TRα1 and Rev-erbα was readily detected in all tissues of M. domestica ages 0 days to 18 weeks, TRα2 mRNA was not detected in any tissue or stage examined. These results contrast with the widespread and abundant expression of TRα2 in rodents and other eutherian mammals. To examine requirements for alternative splicing of TRα mRNAs, a series of chimeric minigenes was constructed. Results show that the opossum TRα2-specific 5' splice site sequence is fully competent for splicing but the sequence homologous to the TRα2 3' splice site is not, even though the marsupial sequences are remarkably similar to core splice site elements in rat. Conclusions Our results strongly suggest that the variant nuclear receptor isoform, TRα2, is not expressed in marsupials and that the antisense overlap between TRα and Rev-erbα thus is unique to eutherian mammals. Further investigation of the TRα and Rev-erbα genes in marsupial and eutherian species promises to yield additional insight into the

Nuclear receptor NHR-25 is required for cell-shape dynamics during epidermal differentiation in Caenorhabditis elegans

Czech Academy of Sciences Publication Activity Database

Šilhánková, Marie; Jindra, Marek; Asahina, Masako

2005-01-01

Roč. 118, č. 1 (2005), s. 223-232 ISSN 0021-9533 R&D Projects: GA AV ČR KJB5022303; GA ČR GD524/03/H133 Institutional research plan: CEZ:AV0Z60220518 Keywords : Caenorhabditis elegans * nuclear receptor * epidermal stem cells Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.543, year: 2005

Yes-Associated Protein (YAP) Promotes the Nuclear Import of p73

International Nuclear Information System (INIS)

Zhang Heng; Wu Shengnan

2011-01-01

p73 has been identified as a structural and functional homolog of the tumor suppressor p53. However, mechanisms that regulate the localization of p73 have not been fully clarified. The Yes-associated protein (YAP) is a transcriptional coactivator. As a transcriptional coactivator, YAP needs to bind transcription factors to stimulate gene expression. p73 is a reported YAP target transcription factors and YAP has been shown to positively regulate p73 in promoting apoptosis. Previous studies show that p73 interacts with YAP through its PPPY motif, and increases p73 transactivation of apoptotic genes. In this study, we focused on YAP's regulation of the localization of p73. After transient transfection into Rat pheochromocytoma (PC12) cells and Human embryonic kidney 293T cells with GFP-YAP and/or YFP-p73, and incubated for 24 hours expression. p73 was fused to YFP to allow the examination of its subcellular localization. When expressed alone, YFP-p73 was distributed throughout the cell. When coexpressed with YAP, nuclear accumulation of YFP-p73 became evident. We quantitated the effect of YAP on the redistribution of YFP-p73 by counting cells with nuclear-only YFP signal. We found that YAP can influence the subcellular distribution of p73. Altogether, coexpression with YAP affected the subcellular distribution of the p73 protein. Our studies attribute a central role to YAP in regulating p73 accumulation and YAP, at least in part, might promote the nuclear import of p73.

CD86 and beta2-adrenergic receptor signaling pathways, respectively, increase Oct-2 and OCA-B Expression and binding to the 3'-IgH enhancer in B cells.

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Podojil, Joseph R; Kin, Nicholas W; Sanders, Virginia M

2004-05-28

Stimulation of CD86 (formerly known as B7-2) and/or the beta2-adrenergic receptor on a CD40 ligand/interleukin-4-activated B cell increased the rate of mature IgG1 transcription. To identify the mechanism responsible for this effect, we determined whether CD86 and/or beta2-adrenergic receptor stimulation regulated transcription factor expression and binding to the 3'-IgH enhancer in vitro and in vivo. We showed that CD86 stimulation increased the nuclear localization of NF-kappaB1 (p50) and phosphorylated RelA (p65) and increased Oct-2 expression and binding to the 3'-IgH enhancer, in a protein kinase C-dependent manner. These effects were lost when CD86-deficient or NF-kappaB1-deficient B cells were used. CD86 stimulation also increased the level of IkappaB-alpha phosphorylation but in a protein kinase C-independent manner. Beta2-adrenergic receptor stimulation increased CREB phosphorylation, OCA-B expression, and OCA-B binding to the 3'-IgH enhancer in a protein kinase A-dependent manner, an effect lost when beta2-adrenergic receptor-deficient B cells were used. Also, the beta2-adrenergic receptor-induced increase in the level of mature IgG1 transcript was lost when OCA-B-deficient B cells were used. These data are the first to show that CD86 stimulation up-regulates the expression of the transcription factor Oct-2 in a protein kinase C- and NF-kappaB1-dependent manner, and that beta2-adrenergic receptor stimulation up-regulates the expression of the coactivator OCA-B in a protein kinase A-dependent manner to cooperate with Oct-2 binding to the 3'-IgH enhancer.

Hormone-dependent nuclear export of estradiol receptor and DNA synthesis in breast cancer cells

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Lombardi, Maria; Castoria, Gabriella; Migliaccio, Antimo; Barone, Maria Vittoria; Di Stasio, Rosina; Ciociola, Alessandra; Bottero, Daniela; Yamaguchi, Hiroshi; Appella, Ettore; Auricchio, Ferdinando

2008-01-01

In breast cancer cells, cytoplasmic localization of the estradiol receptor α (ERα) regulates estradiol-dependent S phase entry. We identified a nuclear export sequence (NES) in ERα and show that its export is dependent on both estradiol-mediated phosphatidylinositol-3-kinase (PI3K)/AKT activation and chromosome region maintenance 1 (CRM1). A Tat peptide containing the ERα NES disrupts ERα–CRM1 interaction and prevents nuclear export of ERα- and estradiol-induced DNA synthesis. NES-ERα mutants do not exit the nucleus and inhibit estradiol-induced S phase entry; ERα-dependent transcription is normal. ERα is associated with Forkhead proteins in the nucleus, and estradiol stimulates nuclear exit of both proteins. ERα knockdown or ERα NES mutations prevent ERα and Forkhead nuclear export. A mutant of forkhead in rhabdomyosarcoma (FKHR), which cannot be phosphorylated by estradiol-activated AKT, does not associate with ERα and is trapped in the nucleus, blocking S phase entry. In conclusion, estradiol-induced AKT-dependent phosphorylation of FKHR drives its association with ERα, thereby triggering complex export from the nucleus necessary for initiation of DNA synthesis and S phase entry. PMID:18644889

S phase activation of the histone H2B promoter by OCA-S, a coactivator complex that contains GAPDH as a key component.

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Zheng, Lei; Roeder, Robert G; Luo, Yan

2003-07-25

We have isolated and functionally characterized a multicomponent Oct-1 coactivator, OCA-S which is essential for S phase-dependent histone H2B transcription. The p38 component of OCA-S binds directly to Oct-1, exhibits potent transactivation potential, is selectively recruited to the H2B promoter in S phase, and is essential for S phase-specific H2B transcription in vivo and in vitro. Surprisingly, p38 represents a nuclear form of glyceraldehyde-3-phosphate dehydrogenase, and binding to Oct-1, as well as OCA-S function, is stimulated by NAD(+) but inhibited by NADH. OCA-S also interacts with NPAT, a cyclin E/cdk2 substrate that is broadly involved in histone gene transcription. These studies thus link the H2B transcriptional machinery to cell cycle regulators, and possibly to cellular metabolic state (redox status), and set the stage for studies of the underlying mechanisms and the basis for coordinated histone gene expression and coupling to DNA replication.

Growth hormone-specific induction of the nuclear localization of porcine growth hormone receptor in porcine hepatocytes.

Science.gov (United States)

Lan, H N; Hong, P; Li, R N; Shan, A S; Zheng, X

2017-10-01

The phenomenon of nuclear translocation of growth hormone receptor (GHR) in human, rat, and fish has been reported. To date, this phenomenon has not been described in a domestic animal (such as pig). In addition, the molecular mechanisms of GHR nuclear translocation have not been thoroughly elucidated. To this end, porcine hepatocytes were isolated and used as a cell model. We observed that porcine growth hormone (pGH) can induce porcine GHR's nuclear localization in porcine hepatocytes. Subsequently, the dynamics of pGH-induced pGHR's nuclear localization were analyzed and demonstrated that pGHR's nuclear localization occurs in a time-dependent manner. Next, we explored the mechanism of pGHR nuclear localization using different pGHR ligands, and we demonstrated that pGHR's nuclear translocation is GH(s)-dependent. We also observed that pGHR translocates into cell nuclei in a pGH dimerization-dependent fashion, whereas further experiments indicated that IMPα/β is involved in the nuclear translocation of the pGH-pGHR dimer. The pGH-pGHR dimer may form a pGH-GHR-JAK2 multiple complex in cell nuclei, which would suggest that similar to its function in the cell membrane, the nuclear-localized pGH-pGHR dimer might still have the ability to signal. Copyright © 2017 Elsevier Inc. All rights reserved.

Liver X receptor α and farnesoid X receptor are major transcriptional regulators of OATP1B1.

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Meyer Zu Schwabedissen, Henriette E; Böttcher, Kerstin; Chaudhry, Amarjit; Kroemer, Heyo K; Schuetz, Erin G; Kim, Richard B

2010-11-01

Organic anion transporting polypeptide 1B1 (OATP1B1) is a liver-enriched transporter involved in the hepatocellular uptake of many endogenous molecules and several structurally divergent drugs in clinical use. Although OATP1B1 coding region polymorphisms are known to make an impact on substrate drug disposition in humans, little is known regarding the mechanisms underlying the transcriptional regulation of this transporter. In this study, we note that messenger RNA (mRNA) expression of OATP1B1 in a large human liver bank exhibited marked interindividual variability that was not associated with coding region polymorphisms. Accordingly, we hypothesized that such variability in expression is reflective of nuclear receptor-mediated transcriptional regulation of this transporter. We tested prototypical ligands for the nuclear receptors pregnane X receptor (PXR), constitutive androstane receptor (CAR), liver X receptor (LXR) α, and farnesoid X receptor (FXR) in a human hepatoma-derived cell line and noted induction of OATP1B1 mRNA when the cells were treated with LXRα or FXR ligands. To confirm a direct role for LXRα and FXR to OATP1B1 expression, we performed detailed promoter analysis and cell-based reporter gene assays resulting in the identification of two functional FXR response elements and one LXRα response element. The direct interaction between nuclear receptors with the identified response elements was assessed using chromatin immunoprecipitation assays. Using isolated primary human hepatocytes, we show that LXRα or FXR agonists, but not PXR or CAR agonists, are capable of OATP1B1 induction. We note that OATP1B1 transcriptional regulation is under dual nuclear receptor control through the oxysterol sensing LXRα and the bile acid sensor FXR. Accordingly, the interplay between OATP1B1 and nuclear receptors may play an important and heretofore unrecognized role during cholestasis, drug-induced liver injury, and OATP1B1 induction-related drug interactions.

Hepatic oxidative stress in ovariectomized transgenic mice expressing the hepatitis C virus polyprotein is augmented through suppression of adenosine monophosphate-activated protein kinase/proliferator-activated receptor gamma co-activator 1 alpha signaling.

Science.gov (United States)

Tomiyama, Yasuyuki; Nishina, Sohji; Hara, Yuichi; Kawase, Tomoya; Hino, Keisuke

2014-10-01

Oxidative stress plays an important role in hepatocarcinogenesis of hepatitis C virus (HCV)-related chronic liver diseases. Despite the evidence of an increased proportion of females among elderly patients with HCV-related hepatocellular carcinoma (HCC), it remains unknown whether HCV augments hepatic oxidative stress in postmenopausal women. The aim of this study was to determine whether oxidative stress was augmented in ovariectomized (OVX) transgenic mice expressing the HCV polyprotein and to investigate its underlying mechanisms. OVX and sham-operated female transgenic mice expressing the HCV polyprotein and non-transgenic littermates were assessed for the production of reactive oxygen species (ROS), expression of inflammatory cytokines and antioxidant potential in the liver. Compared with OVX non-transgenic mice, OVX transgenic mice showed marked hepatic steatosis and ROS production without increased induction of inflammatory cytokines, but there was no increase in ROS-detoxifying enzymes such as superoxide dismutase 2 and glutathione peroxidase 1. In accordance with these results, OVX transgenic mice showed less activation of peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α), which is required for the induction of ROS-detoxifying enzymes, and no activation of adenosine monophosphate-activated protein kinase-α (AMPKα), which regulates the activity of PGC-1α. Our study demonstrated that hepatic oxidative stress was augmented in OVX transgenic mice expressing the HCV polyprotein by attenuation of antioxidant potential through inhibition of AMPK/PGC-1α signaling. These results may account in part for the mechanisms by which HCV-infected women are at high risk for HCC development when some period has passed after menopause. © 2013 The Japan Society of Hepatology.

CINPA1 is an inhibitor of constitutive androstane receptor that does not activate pregnane X receptor.

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Cherian, Milu T; Lin, Wenwei; Wu, Jing; Chen, Taosheng

2015-05-01

Constitutive androstane receptor (CAR) and pregnane X receptor (PXR) are xenobiotic sensors that enhance the detoxification and elimination of xenobiotics and endobiotics by modulating the expression of genes encoding drug-metabolizing enzymes and transporters. Elevated levels of drug-metabolizing enzymes and efflux transporters, resulting from CAR activation in various cancers, promote the elimination of chemotherapeutic agents, leading to reduced therapeutic effectiveness and acquired drug resistance. CAR inhibitors, in combination with existing chemotherapeutics, could therefore be used to attenuate multidrug resistance in cancers. Interestingly, all previously reported CAR inverse-agonists are also activators of PXR, rendering them mechanistically counterproductive in tissues where both these xenobiotic receptors are present and active. We used a directed high-throughput screening approach, followed by subsequent mechanistic studies, to identify novel, potent, and specific small-molecule CAR inhibitors that do not activate PXR. We describe here one such inhibitor, CINPA1 (CAR inhibitor not PXR activator 1), capable of reducing CAR-mediated transcription with an IC50 of ∼70 nM. CINPA1 1) is a specific xenobiotic receptor inhibitor and has no cytotoxic effects up to 30 µM; 2) inhibits CAR-mediated gene expression in primary human hepatocytes, where CAR is endogenously expressed; 3) does not alter the protein levels or subcellular localization of CAR; 4) increases corepressor and reduces coactivator interaction with the CAR ligand-binding domain in mammalian two-hybrid assays; and 5) disrupts CAR binding to the promoter regions of target genes in chromatin immunoprecipitation assays. CINPA1 could be used as a novel molecular tool for understanding CAR function. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

The Orphan Nuclear Receptor TLX/NR2E1 in Neural Stem Cells and Diseases

OpenAIRE

Wang, Tao; Xiong, Jian-Qiong

2016-01-01

The human TLX gene encodes an orphan nuclear receptor predominantly expressed in the central nervous system. Tailess and Tlx, the TLX homologues in Drosophila and mouse, play essential roles in body-pattern formation and neurogenesis during early embryogenesis and perform crucial functions in maintaining stemness and controlling the differentiation of adult neural stem cells in the central nervous system, especially the visual system. Multiple target genes and signaling pathways are regulated...

Hydroxylated polybrominated diphenyl ethers exhibit different activities on thyroid hormone receptors depending on their degree of bromination.

Science.gov (United States)

Ren, Xiao-Min; Guo, Liang-Hong; Gao, Yu; Zhang, Bin-Tian; Wan, Bin

2013-05-01

Polybrominated diphenyl ethers (PBDEs) have been shown to disrupt thyroid hormone (TH) functions in experimental animals, and one of the proposed disruption mechanisms is direct binding of hydroxylated PBDE (OH-PBDE) to TH receptors (TRs). However, previous data on TH receptor binding and TH activity of OH-PBDEs were very limited and sometimes inconsistent. In the present paper, we examined the binding potency of ten OH-PBDEs with different degrees of bromination to TR using a fluorescence competitive binding assay. The results showed that the ten OH-PBDEs bound to TR with potency that correlated to their bromination level. We further examined their effect on TR using a coactivator binding assay and GH3 cell proliferation assay. Different TR activities of OH-PBDEs were observed depending on their degree of bromination. Four low-brominated OH-PBDEs (2'-OH-BDE-28, 3'-OH-BDE-28, 5-OH-BDE-47, 6-OH-BDE-47) were found to be TR agonists, which recruited the coactivator peptide and enhanced GH3 cell proliferation. However, three high-brominated OH-PBDEs (3-OH-BDE-100, 3'-OH-BDE-154, 4-OH-BDE-188) were tested to be antagonists. Molecular docking was employed to simulate the interactions of OH-PBDEs with TR and identify the structural determinants for TR binding and activity. According to the docking results, low-brominated OH-PBDEs, which are weak binders but TR agonists, bind with TR at the inner side of its binding pocket, whereas high-brominated compounds, which are potent binders but TR antagonists, reside at the outer region. These results indicate that OH-PBDEs have different activities on TR (agonistic or antagonistic), possibly due to their different binding geometries with the receptor. Copyright © 2013 Elsevier Inc. All rights reserved.

The Orphan Nuclear Receptor TLX Is an Enhancer of STAT1-Mediated Transcription and Immunity to Toxoplasma gondii.

Directory of Open Access Journals (Sweden)

Daniel P Beiting

2015-07-01

Full Text Available The protozoan parasite, Toxoplasma, like many intracellular pathogens, suppresses interferon gamma (IFN-γ-induced signal transducer and activator of transcription 1 (STAT1 activity. We exploited this well-defined host-pathogen interaction as the basis for a high-throughput screen, identifying nine transcription factors that enhance STAT1 function in the nucleus, including the orphan nuclear hormone receptor TLX. Expression profiling revealed that upon IFN-γ treatment TLX enhances the output of a subset of IFN-γ target genes, which we found is dependent on TLX binding at those loci. Moreover, infection of TLX deficient mice with the intracellular parasite Toxoplasma results in impaired production of the STAT1-dependent cytokine interleukin-12 by dendritic cells and increased parasite burden in the brain during chronic infection. These results demonstrate a previously unrecognized role for this orphan nuclear hormone receptor in regulating STAT1 signaling and host defense and reveal that STAT1 activity can be modulated in a context-specific manner by such "modifiers."

The Orphan Nuclear Receptor TLX Is an Enhancer of STAT1-Mediated Transcription and Immunity to Toxoplasma gondii.

Science.gov (United States)

Beiting, Daniel P; Hidano, Shinya; Baggs, Julie E; Geskes, Jeanne M; Fang, Qun; Wherry, E John; Hunter, Christopher A; Roos, David S; Cherry, Sara

2015-07-01

The protozoan parasite, Toxoplasma, like many intracellular pathogens, suppresses interferon gamma (IFN-γ)-induced signal transducer and activator of transcription 1 (STAT1) activity. We exploited this well-defined host-pathogen interaction as the basis for a high-throughput screen, identifying nine transcription factors that enhance STAT1 function in the nucleus, including the orphan nuclear hormone receptor TLX. Expression profiling revealed that upon IFN-γ treatment TLX enhances the output of a subset of IFN-γ target genes, which we found is dependent on TLX binding at those loci. Moreover, infection of TLX deficient mice with the intracellular parasite Toxoplasma results in impaired production of the STAT1-dependent cytokine interleukin-12 by dendritic cells and increased parasite burden in the brain during chronic infection. These results demonstrate a previously unrecognized role for this orphan nuclear hormone receptor in regulating STAT1 signaling and host defense and reveal that STAT1 activity can be modulated in a context-specific manner by such "modifiers."

Abscisic acid promotes proteasome-mediated degradation of the transcription coactivator NPR1 in Arabidopsis thaliana.

Science.gov (United States)

Ding, Yezhang; Dommel, Matthew; Mou, Zhonglin

2016-04-01

Proteasome-mediated turnover of the transcription coactivator NPR1 is pivotal for efficient activation of the broad-spectrum plant immune responses known as localized acquired resistance (LAR) and systemic acquired resistance (SAR) in adjacent and systemic tissues, respectively, and requires the CUL3-based E3 ligase and its adaptor proteins, NPR3 and NPR4, which are receptors for the signaling molecule salicylic acid (SA). It has been shown that SA prevents NPR1 turnover under non-inducing and LAR/SAR-inducing conditions, but how cellular NPR1 homeostasis is maintained remains unclear. Here, we show that the phytohormone abscisic acid (ABA) and SA antagonistically influence cellular NPR1 protein levels. ABA promotes NPR1 degradation via the CUL3(NPR) (3/) (NPR) (4) complex-mediated proteasome pathway, whereas SA may protect NPR1 from ABA-promoted degradation through phosphorylation. Furthermore, we demonstrate that the timing and strength of SA and ABA signaling are critical in modulating NPR1 accumulation and target gene expression. Perturbing ABA or SA signaling in adjacent tissues alters the temporal dynamic pattern of NPR1 accumulation and target gene transcription. Finally, we show that sequential SA and ABA treatment leads to dynamic changes in NPR1 protein levels and target gene expression. Our results revealed a tight correlation between sequential SA and ABA signaling and dynamic changes in NPR1 protein levels and NPR1-dependent transcription in plant immune responses. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Deficiency of the NR4A Orphan Nuclear Receptor NOR1 attenuates Neointima Formation Following Vascular Injury

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Nomiyama, Takashi; Zhao, Yue; Gizard, Florence; Findeisen, Hannes M.; Heywood, Elizabeth B.; Jones, Karrie L.; Conneely, Orla M.; Bruemmer, Dennis

2009-01-01

Background The neuron-derived orphan receptor-1 (NOR1) belongs to the evolutionary highly conserved and most ancient NR4A subfamily of the nuclear hormone receptor superfamily. Members of this subfamily function as early response genes regulating key cellular processes including proliferation, differentiation, and survival. Although NOR1 has previously been demonstrated to be required for smooth muscle cell (SMC) proliferation in vitro, the role of this nuclear receptor for the proliferative response underlying neointima formation and target genes trans-activated by NOR1 remain to be defined. Methods and Results Using a model of guide wire-induced arterial injury, we demonstrate decreased neointima formation in NOR1-/- mice compared to wildtype mice. In vitro, NOR1-deficient SMC exhibit decreased proliferation due to a G1→S phase arrest of the cell cycle and increased apoptosis in response to serum deprivation. NOR1-deficiency alters phosphorylation of the retinoblastoma protein by preventing mitogen-induced cyclin D1 and D2 expression. Conversely, overexpression of NOR1 induces cyclin D1 expression and the transcriptional activity of the cyclin D1 promoter in transient reporter assays. Gel shift and chromatin immunoprecipitation assays identified a putative response element for NR4A receptors in the cyclin D1 promoter, to which NOR1 is recruited in response to mitogenic stimulation. Finally, we provide evidence that these observations are applicable in vivo by demonstrating decreased cyclin D1 expression during neointima formation in NOR1-deficient mice. Conclusions These experiments characterize cyclin D1 as a NOR1-regulated target gene in SMC and demonstrate that NOR1 deficiency decreases neointima formation in response to vascular injury. PMID:19153266

Orphan nuclear receptor NR4A1 is a negative regulator of DHT-induced rat preantral follicular growth.

Science.gov (United States)

Xue, Kai; Liu, Jia-yin; Murphy, Bruce D; Tsang, Benjamin K

2012-12-01

Nuclear receptor subfamily 4 group A member1 (NR4A1), an orphan nuclear receptor, is involved in the transcriptional regulation of thecal cell androgen biosynthesis and paracrine factor insulin-like 3 (INSL3) expression. Androgens are known to play an important regulatory role in ovarian follicle growth. Using a chronically androgenized rat model, a preantral follicle culture model and virus-mediated gene delivery, we examined the role and regulation of NR4A1 in the androgenic control of preantral follicular growth. In the present study, Ki67 staining was increased in preantral follicles on ovarian sections from 5α-dihydrotestosterone (DHT)-treated rats. Preantral follicles from DHT-treated rats cultured for 4 d exhibited increased growth and up-regulation of mRNA abundance of G(1)/S-specific cyclin-D2 (Ccnd2) and FSH receptor (Fshr). Similarly, DHT (1 μm) increased preantral follicular growth and Ccnd2 and Fshr mRNA abundance in vitro. The NR4A1 expression was high in theca cells and was down-regulated by DHT in vivo and in vitro. Forced expression of NR4A1 augmented preantral follicular growth, androstenedione production, and Insl3 expression in vitro. Inhibiting the action of androgen (with androgen receptor antagonist flutamide) or INSL3 (with INSL3 receptor antagonist INSL3 B-chain) reduced NR4A1-induced preantral follicular growth. Furthermore, NR4A1 overexpression enhanced DHT-induced preantral follicular growth, a response attenuated by inhibiting INSL3. In conclusion, DHT promotes preantral follicular growth and attenuates thecal NR4A1 expression in vivo and in vitro. Our findings are consistent with the notion that NR4A1 serves as an important point of negative feedback to minimize the excessive preantral follicle growth in hyperandrogenism.

The impact of language co-activation on L1 and L2 speech fluency.

Science.gov (United States)

Bergmann, Christopher; Sprenger, Simone A; Schmid, Monika S

2015-10-01

Fluent speech depends on the availability of well-established linguistic knowledge and routines for speech planning and articulation. A lack of speech fluency in late second-language (L2) learners may point to a deficiency of these representations, due to incomplete acquisition. Experiments on bilingual language processing have shown, however, that there are strong reasons to believe that multilingual speakers experience co-activation of the languages they speak. We have studied to what degree language co-activation affects fluency in the speech of bilinguals, comparing a monolingual German control group with two bilingual groups: 1) first-language (L1) attriters, who have fully acquired German before emigrating to an L2 English environment, and 2) immersed L2 learners of German (L1: English). We have analysed the temporal fluency and the incidence of disfluency markers (pauses, repetitions and self-corrections) in spontaneous film retellings. Our findings show that learners to speak more slowly than controls and attriters. Also, on each count, the speech of at least one of the bilingual groups contains more disfluency markers than the retellings of the control group. Generally speaking, both bilingual groups-learners and attriters-are equally (dis)fluent and significantly more disfluent than the monolingual speakers. Given that the L1 attriters are unaffected by incomplete acquisition, we interpret these findings as evidence for language competition during speech production. Copyright © 2015. Published by Elsevier B.V.

Co-activated yet disconnected-Neural correlates of eye closures when trying to stay awake.

Science.gov (United States)

Ong, Ju Lynn; Kong, Danyang; Chia, Tiffany T Y; Tandi, Jesisca; Thomas Yeo, B T; Chee, Michael W L

2015-09-01

Spontaneous eye-closures that herald sleep onset become more frequent when we are sleep deprived. Although these are typically associated with decreased responsiveness to external stimuli, it is less clear what occurs in the brain at these transitions to drowsiness and light sleep. To investigate this, task-free fMRI of sleep-deprived participants was acquired. BOLD activity associated with periods of spontaneously occurring eye closures were marked and analyzed. We observed concurrent and extensive hypnagogic co-activation of the extrastriate visual, auditory, and somatosensory cortices as well as the default mode network, consistent with internal sensory activity without external stimulation. Co-activation of fronto-parietal areas known to mediate attentional control could correspond with participants resisting sleep or additional engagement of mental imagery. This constellation of signal changes differed from those elicited by cued eye closures of similar duration and distribution in the same, rested participants. They also differ from signal changes associated with mind-wandering and consolidated light sleep. Concurrent with the observed event-related changes, eye closures elicited additional reduction in functional connectivity within nodes of the DMN and DAN, superposed on already reduced connectivity associated with sleep deprivation. There was concurrent deactivation of the thalamus during eye-closure during the sleep-deprived state but almost similar changes occurred in the well-rested state that may also be relevant. These findings highlight the dynamic shifts in brain activity and connectivity at border between wakefulness and sleep. Copyright © 2015. Published by Elsevier Inc.

ING3 promotes prostate cancer growth by activating the androgen receptor.

Science.gov (United States)

Nabbi, Arash; McClurg, Urszula L; Thalappilly, Subhash; Almami, Amal; Mobahat, Mahsa; Bismar, Tarek A; Binda, Olivier; Riabowol, Karl T

2017-05-16

The androgen receptor (AR) is a major driver of prostate cancer, and increased AR levels and co-activators of the receptor promote the development of prostate cancer. INhibitor of Growth (ING) proteins target lysine acetyltransferase or lysine deacetylase complexes to the histone H3K4Me3 mark of active transcription, to affect chromatin structure and gene expression. ING3 is a stoichiometric member of the TIP60 lysine acetyltransferase complex implicated in prostate cancer development. Biopsies of 265 patients with prostate cancer were stained for ING3, pan-cytokeratin, and DNA. LNCaP and C4-2 androgen-responsive cells were used for in vitro assays including immunoprecipitation, western blotting, Luciferase reporter assay and quantitative polymerase chain reaction. Cell viability and migration assays were performed in prostate cancer cell lines using scrambled siRNA or siRNA targeting ING3. We find that ING3 levels and AR activity positively correlate in prostate cancer. ING3 potentiates androgen effects, increasing expression of androgen-regulated genes and androgen response element-driven reporters to promote growth and anchorage-independent growth. Conversely, ING3 knockdown inhibits prostate cancer cell growth and invasion. ING3 activates the AR by serving as a scaffold to increase interaction between TIP60 and the AR in the cytoplasm, enhancing receptor acetylation and translocation to the nucleus. Activation is independent of ING3's ability to target the TIP60 complex to H3K4Me3, identifying a previously unknown chromatin-independent cytoplasmic activity for ING3. In agreement with in vitro observations, analysis of The Cancer Genome Atlas (TCGA) data (n = 498) and a prostate cancer tissue microarray (n = 256) show that ING3 levels are higher in aggressive prostate cancers, with high levels of ING3 predicting shorter patient survival in a low AR subgroup. Including ING3 levels with currently used indicators such as the Gleason score provides more

Expression profiling of nuclear receptors in breast cancer identifies TLX as a mediator of growth and invasion in triple-negative breast cancer.

Science.gov (United States)

Lin, Meng-Lay; Patel, Hetal; Remenyi, Judit; Banerji, Christopher R S; Lai, Chun-Fui; Periyasamy, Manikandan; Lombardo, Ylenia; Busonero, Claudia; Ottaviani, Silvia; Passey, Alun; Quinlan, Philip R; Purdie, Colin A; Jordan, Lee B; Thompson, Alastair M; Finn, Richard S; Rueda, Oscar M; Caldas, Carlos; Gil, Jesus; Coombes, R Charles; Fuller-Pace, Frances V; Teschendorff, Andrew E; Buluwela, Laki; Ali, Simak

2015-08-28

The Nuclear Receptor (NR) superfamily of transcription factors comprises 48 members, several of which have been implicated in breast cancer. Most important is estrogen receptor-α (ERα), which is a key therapeutic target. ERα action is facilitated by co-operativity with other NR and there is evidence that ERα function may be recapitulated by other NRs in ERα-negative breast cancer. In order to examine the inter-relationships between nuclear receptors, and to obtain evidence for previously unsuspected roles for any NRs, we undertook quantitative RT-PCR and bioinformatics analysis to examine their expression in breast cancer. While most NRs were expressed, bioinformatic analyses differentiated tumours into distinct prognostic groups that were validated by analyzing public microarray data sets. Although ERα and progesterone receptor were dominant in distinguishing prognostic groups, other NR strengthened these groups. Clustering analysis identified several family members with potential importance in breast cancer. Specifically, RORγ is identified as being co-expressed with ERα, whilst several NRs are preferentially expressed in ERα-negative disease, with TLX expression being prognostic in this subtype. Functional studies demonstrated the importance of TLX in regulating growth and invasion in ERα-negative breast cancer cells.

Nuclear Receptor TLX Regulates Cell Cycle Progression in Neural Stem Cells of the Developing Brain

OpenAIRE

Li, Wenwu; Sun, Guoqiang; Yang, Su; Qu, Qiuhao; Nakashima, Kinichi; Shi, Yanhong

2007-01-01

TLX is an orphan nuclear receptor that is expressed exclusively in vertebrate forebrains. Although TLX is known to be expressed in embryonic brains, the mechanism by which it influences neural development remains largely unknown. We show here that TLX is expressed specifically in periventricular neural stem cells in embryonic brains. Significant thinning of neocortex was observed in embryonic d 14.5 TLX-null brains with reduced nestin labeling and decreased cell proliferation in the germinal ...

EXERCISES THAT FACILITATE OPTIMAL HAMSTRING AND QUADRICEPS CO-ACTIVATION TO HELP DECREASE ACL INJURY RISK IN HEALTHY FEMALES: A SYSTEMATIC REVIEW OF THE LITERATURE.

Science.gov (United States)

Dedinsky, Rachel; Baker, Lindsey; Imbus, Samuel; Bowman, Melissa

2017-01-01

Background Anterior cruciate ligament (ACL) injury is common among females due to many anatomic, hormonal, and neuromuscular risk factors. One modifiable risk factor that places females at increased risk of ACL injury is a poor hamstrings: quadriceps (H:Q) co-activation ratio, which should be 0.6 or greater in order to decrease the stress placed on the ACL. Exercises that produce more quadriceps dominant muscle activation can add to the tension placed upon the ACL, potentially increasing the risk of ACL injury. Hypothesis/Purpose The purpose of this systematic review was to compare quadriceps and hamstring muscle activation during common closed kinetic chain therapeutic exercises in healthy female knees to determine what exercises are able to produce adequate H:Q co-activation ratios. Study Design Systematic Review Methods Multiple online databases were systematically searched and screened for inclusion. Eight articles were identified for inclusion. Data on mean electromyography (EMG) activation of both quadriceps and hamstring muscles, % maximal voluntary isometric contraction (MVIC), and H:Q co-activation ratios were extracted from the studies. Quality assessment was performed on all included studies. Results Exercises analyzed in the studies included variations of the double leg squat, variations of the single leg squat, lateral step-up, Fitter, Stairmaster® (Core Health and Fitness, Vancouver, WA), and slide board. All exercises, except the squat machine with posterior support at the level of the scapula and feet placed 50 cm in front of the hips, produced higher quadriceps muscle activation compared to hamstring muscle activation. Conclusion Overall, two leg squats demonstrate poor H:Q co-activation ratios. Single leg exercises, when performed between 30 and 90 degrees of knee flexion, produce adequate H:Q ratios, thereby potentially reducing the risk of tensile stress on the ACL and ACL injury. Level of Evidence 2a- Systematic Review of Cohort Studies PMID

Carob pod insoluble fiber exerts anti-atherosclerotic effects in rabbits through sirtuin-1 and peroxisome proliferator-activated receptor-γ coactivator-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 receptor-γ coactivator-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

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.

A Review About Lycopene-Induced Nuclear Hormone Receptor Signalling in Inflammation and Lipid Metabolism via still Unknown Endogenous Apo-10´-Lycopenoids.

Science.gov (United States)

Caris-Veyrat, Catherine; Garcia, Ada L; Reynaud, Eric; Lucas, Renata; Aydemir, Gamze; Rühl, Ralph

2017-10-20

Lycopene is the red pigment in tomatoes and tomato products and is an important dietary carotenoid found in the human organism. Lycopene-isomers, oxidative lycopene metabolites and apo-lycopenoids are found in the food matrix. Lycopene intake derived from tomato consumption is associated with alteration of lipid metabolism and a lower incidence of cardiovascular diseases (CVD). Lycopene is mainly described as a potent antioxidant but novel studies are shifting towards its metabolites and their capacity to mediate nuclear receptor signalling. Di-/tetra-hydro-derivatives of apo-10´-lycopenoic acid and apo-15´-lycopenoic acids are potential novel endogenous mammalian lycopene metabolites which may act as ligands for nuclear hormone mediated activation and signalling. In this review, we postulate that complex lycopene metabolism results in various lycopene metabolites which have the ability to mediate transactivation of various nuclear hormone receptors like RARs, RXRs and PPARs. A new mechanistic explanation of how tomato consumption could positively modulate inflammation and lipid metabolism is discussed.

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

Drosophila MBF1 is a co-activator for Tracheae Defective and contributes to the formation of tracheal and nervous systems

Czech Academy of Sciences Publication Activity Database

Liu, Q. X.; Jindra, Marek; Ueda, H.; Hiromi, Y.; Hirose, S.

2003-01-01

Roč. 130, - (2003), s. 719-728 ISSN 0950-1991 R&D Projects: GA ČR GA204/00/0811 Institutional research plan: CEZ:AV0Z5007907 Keywords : TDF * MBF1 * co-activator Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 7.663, year: 2003

SUMOylation regulates the nuclear mobility of CREB binding protein and its association with nuclear bodies in live cells

International Nuclear Information System (INIS)

Ryan, Colm M.; Kindle, Karin B.; Collins, Hilary M.; Heery, David M.

2010-01-01

The lysine acetyltransferase CREB binding protein (CBP) is required for chromatin modification and transcription at many gene promoters. In fixed cells, a large proportion of CBP colocalises to PML or nuclear bodies. Using live cell imaging, we show here that YFP-tagged CBP expressed in HEK293 cells undergoes gradual accumulation in nuclear bodies, some of which are mobile and migrate towards the nuclear envelope. Deletion of a short lysine-rich domain that contains the major SUMO acceptor sites of CBP abrogated its ability to be SUMO modified, and prevented its association with endogenous SUMO-1/PML speckles in vivo. This SUMO-defective CBP showed enhanced ability to co-activate AML1-mediated transcription. Deletion mapping revealed that the SUMO-modified region was not sufficient for targeting CBP to PML bodies, as C-terminally truncated mutants containing this domain showed a strong reduction in accumulation at PML bodies. Fluorescence recovery after photo-bleaching (FRAP) experiments revealed that YFP-CBPΔ998-1087 had a retarded recovery time in the nucleus, as compared to YFP-CBP. These results indicate that SUMOylation regulates CBP function by influencing its shuttling between nuclear bodies and chromatin microenvironments.

SUMOylation regulates the nuclear mobility of CREB binding protein and its association with nuclear bodies in live cells

Energy Technology Data Exchange (ETDEWEB)

Ryan, Colm M.; Kindle, Karin B.; Collins, Hilary M. [Gene Regulation Group, Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Heery, David M., E-mail: david.heery@nottingham.ac.uk [Gene Regulation Group, Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2010-01-01

The lysine acetyltransferase CREB binding protein (CBP) is required for chromatin modification and transcription at many gene promoters. In fixed cells, a large proportion of CBP colocalises to PML or nuclear bodies. Using live cell imaging, we show here that YFP-tagged CBP expressed in HEK293 cells undergoes gradual accumulation in nuclear bodies, some of which are mobile and migrate towards the nuclear envelope. Deletion of a short lysine-rich domain that contains the major SUMO acceptor sites of CBP abrogated its ability to be SUMO modified, and prevented its association with endogenous SUMO-1/PML speckles in vivo. This SUMO-defective CBP showed enhanced ability to co-activate AML1-mediated transcription. Deletion mapping revealed that the SUMO-modified region was not sufficient for targeting CBP to PML bodies, as C-terminally truncated mutants containing this domain showed a strong reduction in accumulation at PML bodies. Fluorescence recovery after photo-bleaching (FRAP) experiments revealed that YFP-CBP{Delta}998-1087 had a retarded recovery time in the nucleus, as compared to YFP-CBP. These results indicate that SUMOylation regulates CBP function by influencing its shuttling between nuclear bodies and chromatin microenvironments.

The Arabidopsis NPR1 Protein Is a Receptor for the Plant Defense Hormone Salicylic Acid

Directory of Open Access Journals (Sweden)

Yue Wu

2012-06-01

Full Text Available Salicylic acid (SA is an essential hormone in plant immunity, but its receptor has remained elusive for decades. The transcriptional coregulator NPR1 is central to the activation of SA-dependent defense genes, and we previously found that Cys521 and Cys529 of Arabidopsis NPR1's transactivation domain are critical for coactivator function. Here, we demonstrate that NPR1 directly binds SA, but not inactive structural analogs, with an affinity similar to that of other hormone-receptor interactions and consistent with in vivo Arabidopsis SA concentrations. Binding of SA occurs through Cys521/529 via the transition metal copper. Mechanistically, our results suggest that binding of SA causes a conformational change in NPR1 that is accompanied by the release of the C-terminal transactivation domain from the N-terminal autoinhibitory BTB/POZ domain. While NPR1 is already known as a link between the SA signaling molecule and defense-gene activation, we now show that NPR1 is the receptor for SA.

Does bilirubin prevent hepatic steatosis through activation of the PPARα nuclear receptor?

Science.gov (United States)

Hinds, Terry D; Adeosun, Samuel O; Alamodi, Abdulhadi A; Stec, David E

2016-10-01

Several large population studies have demonstrated a negative correlation between serum bilirubin levels and the development of obesity, hepatic steatosis, and cardiovascular disease. Despite the strong correlative data demonstrating the protective role of bilirubin, the mechanism by which bilirubin can protect against these pathologies remains unknown. Bilirubin has long been known as a powerful antioxidant and also has anti-inflammatory actions, each of which may contribute to the protection afforded by increased levels. We have recently described a novel function of bilirubin as a ligand for the peroxisome proliferator-activated receptor-alpha (PPARα), which we show specifically binds to the nuclear receptor. Bilirubin may function as a selective PPAR modulator (SPPARM) to control lipid accumulation and blood glucose. However, it is not known to what degree bilirubin activation of PPARα is responsible for the protection afforded to reduce hepatic steatosis. We hypothesize that bilirubin, acting as a novel SPPARM, increases hepatic fatty acid metabolism through a PPARα-dependent mechanism which reduces hepatic lipid accumulation and protects against hepatic steatosis and non-alcoholic fatty liver disease (NAFLD). Copyright © 2016 Elsevier Ltd. All rights reserved.

Different ankle muscle coordination patterns and co-activation during quiet stance between young adults and seniors do not change after a bout of high intensity training.

Science.gov (United States)

Donath, Lars; Kurz, Eduard; Roth, Ralf; Zahner, Lukas; Faude, Oliver

2015-03-04

Available evidence suggests that young adults and seniors use different strategies to adjust for increasing body sway during quiet standing. Altered antagonist muscle co-activation and different ankle muscle coordination patterns may account for this finding. Consequently, we aimed at addressing whether aging leads to changes in neuromuscular coordination patterns as well as co-activation during quiet stance. We additionally investigated whether a bout of high intensity interval training additionally alters these patterns. Twenty healthy seniors (age: 70 ± 4 y) and twenty young adults (age: 27 ± 3 y) were enrolled in the present study. In between the testing procedures, four consecutive high-intensity intervals of 4 min duration at a target exercise intensity of 90 to 95% HRmax were completed on a treadmill. The total center of pressure (COP) path length displacement served as standing balance performance outcome. In order to assess ankle muscle coordination patterns, amplitude ratios (AR) were calculated for each muscle (e.g. tibialis anterior (TA) [%] = (TA × 100)/(gastrocnemius medialis (GM) + soleus (SOL) + peroneus longus (PL) + TA). The co-activation was calculated for the SOL and TA muscles computing the co-activation index (CAI = 2 × TA/TA + SOL). Seniors showed an inverted ankle muscle coordination pattern during single limb stance with eyes open (SLEO), compared to young adults (rest: GM, S: 15 ± 8% vs Y: 24 ± 9%; p = 0.03; SOL, S: 27 ± 14% vs Y: 37 ± 18%; p = 0.009; TA, S: 31 ± 13% vs Y: 13 ± 7%; p = 0.003). These patterns did not change after a high-intensity training session. A moderate correlation between amplitude ratios of the TA-contribution and postural sway was observed for seniors during SLEO (r = 0.61). Ankle co-activation was twofold elevated in seniors compared to young adults during SLEO (p Seniors with decreased postural control showed higher TA

Genomic and non-genomic regulation of PGC1 isoforms by estrogen to increase cerebral vascular mitochondrial biogenesis and reactive oxygen species protection

Science.gov (United States)

Kemper, Martin F.; Stirone, Chris; Krause, Diana N.; Duckles, Sue P.; Procaccio, Vincent

2014-01-01

We previously found that estrogen exerts a novel protective effect on mitochondria in brain vasculature. Here we demonstrate in rat cerebral blood vessels that 17β-estradiol (estrogen), both in vivo and ex vivo, affects key transcriptional coactivators responsible for mitochondrial regulation. Treatment of ovariectomized rats with estrogen in vivo lowered mRNA levels of peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1α) but increased levels of the other PGC-1 isoforms: PGC-1β and PGC-1 related coactivator (PRC). In vessels ex vivo, estrogen decreased protein levels of PGC-1α via activation of phosphatidylinositol 3-kinase (PI3K). Estrogen treatment also increased phosphorylation of forkhead transcription factor, FoxO1, a known pathway for PGC-1α downregulation. In contrast to the decrease in PGC-1α, estrogen increased protein levels of nuclear respiratory factor 1, a known PGC target and mediator of mitochondrial biogenesis. The latter effect of estrogen was independent of PI3K, suggesting a separate mechanism consistent with increased expression of PGC-1β and PRC. We demonstrated increased mitochondrial biogenesis following estrogen treatment in vivo; cerebrovascular levels of mitochondrial transcription factor A and electron transport chain subunits as well as the mitochondrial/ nuclear DNA ratio were increased. We examined a downstream target of PGC-1β, glutamate-cysteine ligase (GCL), the rate-limiting enzyme for glutathione synthesis. In vivo estrogen increased protein levels of both GCL subunits and total glutathione levels. Together these data show estrogen differentially regulates PGC-1 isoforms in brain vasculature, underscoring the importance of these coactivators in adapting mitochondria in specific tissues. By upregulating PGC-1β and/or PRC, estrogen appears to enhance mitochondrial biogenesis, function and reactive oxygen species protection. PMID:24275351

Regulation of behaviour by the nuclear receptor TLX.

Science.gov (United States)

O'Leary, J D; O'Leary, O F; Cryan, J F; Nolan, Y M

2018-03-01

The orphan nuclear receptor Tlx (Nr2e1) is a key regulator of both embryonic and adult hippocampal neurogenesis. Several different mouse models have been developed which target Tlx in vivo including spontaneous deletion models (from birth) and targeted and conditional knockouts. Although some conflicting findings have been reported, for the most part studies have demonstrated that Tlx is important in regulating processes that underlie neurogenesis, spatial learning, anxiety-like behaviour and interestingly, aggression. More recent data have demonstrated that disrupting Tlx during early life induces hyperactivity and that Tlx plays a role in emotional regulation. Moreover, there are sex- and age-related differences in some behaviours in Tlx knockout mice during adolescence and adulthood. Here, we discuss the role of Tlx in motor-, cognitive-, aggressive- and anxiety-related behaviours during adolescence and adulthood. We examine current evidence which provides insight into Tlx during neurodevelopment, and offer our thoughts on the function of Tlx in brain and behaviour. We further hypothesize that Tlx is a key target in understanding the emergence of neurobiological disorders during adolescence and early adulthood. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Nuclear translocation and retention of growth hormone

DEFF Research Database (Denmark)

Mertani, Hichem C; Raccurt, Mireille; Abbate, Aude

2003-01-01

We have previously demonstrated that GH is subject to rapid receptor-dependent nuclear translocation. Here, we examine the importance of ligand activation of the GH-receptor (GHR)-associated Janus kinase (JAK) 2 and receptor dimerization for hormone internalization and nuclear translocation by use...... of cells stably transfected with cDNA for the GHR. Staurosporine and herbimycin A treatment of cells did not affect the ability of GH to internalize but resulted in increased nuclear accumulation of hormone. Similarly, receptor mutations, which prevent the association and activation of JAK2, did not affect...... the ability of the hormone to internalize or translocate to the nucleus but resulted in increased nuclear accumulation of GH. These results were observed both by nuclear isolation and confocal laser scanning microscopy. Staurosporine treatment of cells in which human GH (hGH) was targeted to the cytoplasm...

Rho-kinase signaling controls nucleocytoplasmic shuttling of class IIa Histone Deacetylase (HDAC7) and transcriptional activation of orphan nuclear receptor NR4A1

Energy Technology Data Exchange (ETDEWEB)

Compagnucci, Claudia; Barresi, Sabina [Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy); Petrini, Stefania [Research Laboratories, Confocal Microscopy Core Facility, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy); Bertini, Enrico [Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy); Zanni, Ginevra, E-mail: ginevra.zanni@opbg.net [Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy)

2015-04-03

Rho-kinase (ROCK) has been well documented to play a key role in RhoA-induced actin remodeling. ROCK activation results in myosin light chain (MLC) phosphorylation either by direct action on MLC kinase (MLCK) or by inhibition of MLC phosphatase (MLCP), modulating actin–myosin contraction. We found that inhibition of the ROCK pathway in induced pluripotent stem cells, leads to nuclear export of HDAC7 and transcriptional activation of the orphan nuclear receptor NR4A1 while in cells with constitutive ROCK hyperactivity due to loss of function of the RhoGTPase activating protein Oligophrenin-1 (OPHN1), the orphan nuclear receptor NR4A1 is downregulated. Our study identify a new target of ROCK signaling via myosin phosphatase subunit (MYPT1) and Histone Deacetylase (HDAC7) at the nuclear level and provide new insights in the cellular functions of ROCK. - Highlights: • ROCK regulates nucleocytoplasmic shuttling of HDAC7 via phosphorylation of MYPT1. • Nuclear export of HDAC7 and upregulation of NR4A1 occurs with low ROCK activity. • High levels of ROCK activity due to OPHN1 loss of function downregulate NR4A1.

G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy.

Science.gov (United States)

White, James P; Wrann, Christiane D; Rao, Rajesh R; Nair, Sreekumaran K; Jedrychowski, Mark P; You, Jae-Sung; Martínez-Redondo, Vicente; Gygi, Steven P; Ruas, Jorge L; Hornberger, Troy A; Wu, Zhidan; Glass, David J; Piao, Xianhua; Spiegelman, Bruce M

2014-11-04

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1α4) is a protein isoform derived by alternative splicing of the PGC1α mRNA and has been shown to promote muscle hypertrophy. We show here that G protein-coupled receptor 56 (GPR56) is a transcriptional target of PGC-1α4 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-1α4 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-1α4-induced muscle hypertrophy in vitro. Forced expression of GPR56 results in myotube hypertrophy through the expression of insulin-like growth factor 1, which is dependent on Gα12/13 signaling. A murine model of overload-induced muscle hypertrophy is associated with increased expression of both GPR56 and its ligand collagen type III, whereas genetic ablation of GPR56 expression attenuates overload-induced muscle hypertrophy and associated anabolic signaling. These data illustrate a signaling pathway through GPR56 which regulates muscle hypertrophy associated with resistance/loading-type exercise.

Changes in nuclear receptor corepressor RIP140 do not influence mitochondrial content in the cortex.

Science.gov (United States)

Herbst, Eric A F; Bonen, Arend; Holloway, Graham P

2015-10-01

Changes in nuclear receptor interacting protein 140 (RIP140) influences mitochondrial content in skeletal muscle; however, the translation of these findings to the brain has not been investigated. The present study examined the impact of overexpressing and ablating RIP140 on mitochondrial content in muscle and the cortex through examining mRNA, mtDNA, and mitochondrial protein content. Our results show that changes in RIP140 expression significantly alters markers of mitochondrial content in skeletal muscle but not the brain.

Effects of atorvastatin metabolites on induction of drug-metabolizing enzymes and membrane transporters through human pregnane X receptor

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Hoffart, E; Ghebreghiorghis, L; Nussler, AK; Thasler, WE; Weiss, TS; Schwab, M; Burk, O

2012-01-01

BACKGROUND AND PURPOSE Atorvastatin metabolites differ in their potential for drug interaction because of differential inhibition of drug-metabolizing enzymes and transporters. We here investigate whether they exert differential effects on the induction of these genes via activation of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). EXPERIMENTAL APPROACH Ligand binding to PXR or CAR was analysed by mammalian two-hybrid assembly and promoter/reporter gene assays. Additionally, surface plasmon resonance was used to analyse ligand binding to CAR. Primary human hepatocytes were treated with atorvastatin metabolites, and mRNA and protein expression of PXR-regulated genes was measured. Two-hybrid co-activator interaction and co-repressor release assays were utilized to elucidate the molecular mechanism of PXR activation. KEY RESULTS All atorvastatin metabolites induced the assembly of PXR and activated CYP3A4 promoter activity. Ligand binding to CAR could not be proven. In primary human hepatocytes, the para-hydroxy metabolite markedly reduced or abolished induction of cytochrome P450 and transporter genes. While significant differences in co-activator recruitment were not observed, para-hydroxy atorvastatin demonstrated only 50% release of co-repressors. CONCLUSIONS AND IMPLICATIONS Atorvastatin metabolites are ligands of PXR but not of CAR. Atorvastatin metabolites demonstrate differential induction of PXR target genes, which results from impaired release of co-repressors. Consequently, the properties of drug metabolites have to be taken into account when analysing PXR-dependent induction of drug metabolism and transport. The drug interaction potential of the active metabolite, para-hydroxy atorvastatin, might be lower than that of the parent compound. PMID:21913896

Food Components Modulate Obesity and Energy Metabolism via the Transcriptional Regulation of Lipid-Sensing Nuclear Receptors.

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Goto, Tsuyoshi; Takahashi, Nobuyuki; Kawada, Teruo

2015-01-01

Obesity is a major risk factor for chronic diseases such as diabetes, cardiovascular diseases, and hypertension. Many modern people have a tendency to overeat owing to stress and loosening of self-control. Moreover, energy expenditure varies greatly among individuals. Scientific reduction of obesity is important under these circumstances. Furthermore, recent research on molecular levels has clarified the differentiation of adipocytes, the level of subsequent fat accumulation, and the secretion of the biologically active adipokines by adipocytes. Adipose tissues and obesity have become the most important target for the prevention and treatment of many chronic diseases. We have identified various food-derived compounds modulating nuclear receptors, especially peroxisome proliferators-activated receptor(PPAR), in the regulation of energy metabolism and obesity. In this review, we discuss the PPARs that are most important in obesity and energy metabolism.

SUMO-1 promotes association of SNURF (RNF4) with PML nuclear bodies

International Nuclear Information System (INIS)

Haekli, Marika; Karvonen, Ulla; Jaenne, Olli A.; Palvimo, Jorma J.

2005-01-01

Small nuclear RING finger protein SNURF (RNF4) is involved in transcriptional and cell growth regulation. We show here that a significant portion of endogenous SNURF localizes to nuclear bodies (NBs) that overlap with or are adjacent to domains containing endogenous promyelocytic leukemia (PML) protein and small ubiquitin-like modifier-1 (SUMO-1). In biochemical assays, SNURF efficiently binds SUMO-1 in a noncovalent fashion. SNURF is also covalently modified by SUMO-1 at nonconsensus attachment sites. Ectopic expression of SUMO-1 markedly enhances the interaction between PML3 (PML IV) and SNURF, but covalent attachment of SUMO-1 to neither protein is required. Moreover, overexpression of PML3, but not PML-L (PML III), abolishes the coactivation function of SNURF in transactivation assays, which parallels the ability of PML3 to recruit SNURF to nuclear bodies. In sum, we have identified SNURF as a novel component in PML bodies and suggest that SUMO-1-facilitated sequestration into these nuclear domains regulates the transcriptional activity of SNURF

Nuclear targeting of IGF-1 receptor in orbital fibroblasts from Graves' disease: apparent role of ADAM17.

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Neil Hoa

Full Text Available Insulin-like growth factor-1 receptor (IGF-1R comprises two subunits, including a ligand binding domain on extra- cellular IGF-1Rα and a tyrosine phosphorylation site located on IGF-1Rβ. IGF-1R is over-expressed by orbital fibroblasts in the autoimmune syndrome, Graves' disease (GD. When activated by IGF-1 or GD-derived IgG (GD-IgG, these fibroblasts produce RANTES and IL-16, while those from healthy donors do not. We now report that IGF-1 and GD-IgG provoke IGF-1R accumulation in the cell nucleus of GD fibroblasts where it co-localizes with chromatin. Nuclear IGF-1R is detected with anti-IGF-1Rα-specific mAb and migrates to approximately 110 kDa, consistent with its identity as an IGF-1R fragment. Nuclear IGF-1R migrating as a 200 kDa protein and consistent with an intact receptor was undetectable when probed with either anti-IGF-1Rα or anti-IGF-1Rβ mAbs. Nuclear redistribution of IGF-1R is absent in control orbital fibroblasts. In GD fibroblasts, it can be abolished by an IGF-1R-blocking mAb, 1H7 and by physiological concentrations of glucocorticoids. When cell-surface IGF-1R is cross-linked with (125I IGF-1, (125I-IGF-1/IGF-1R complexes accumulate in the nuclei of GD fibroblasts. This requires active ADAM17, a membrane associated metalloproteinase, and the phosphorylation of IGF-1R. In contrast, virally encoded IGF-1Rα/GFP fusion protein localizes equivalently in nuclei in both control and GD fibroblasts. This result suggests that generation of IGF-1R fragments may limit the accumulation of nuclear IGF-1R. We thus identify a heretofore-unrecognized behavior of IGF-1R that appears limited to GD-derived fibroblasts. Nuclear IGF-1R may play a role in disease pathogenesis.

Transcriptional activation of NAD+-dependent protein deacetylase SIRT1 by nuclear receptor TLX.

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Iwahara, Naotoshi; Hisahara, Shin; Hayashi, Takashi; Horio, Yoshiyuki

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(+)-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.

Transcriptional activation of NAD+-dependent protein deacetylase SIRT1 by nuclear receptor TLX

International Nuclear Information System (INIS)

Iwahara, Naotoshi; Hisahara, Shin; Hayashi, Takashi; Horio, Yoshiyuki

2009-01-01

An orphan nuclear receptor TLX is a transcriptional repressor that promotes the proliferation and self-renewal of neural precursor cells (NPCs). SIRT1, an NAD + -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.

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...

MiR130b-Regulation of PPARγ Coactivator- 1α Suppresses Fat Metabolism in Goat Mammary Epithelial Cells.

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Zhi Chen

Full Text Available Fat metabolism is a complicated process regulated by a series of factors. microRNAs (miRNAs are a class of negative regulator of proteins and play crucial roles in many biological processes; including fat metabolism. Although there have been some researches indicating that miRNAs could influence the milk fat metabolism through targeting some factors, little is known about the effect of miRNAs on goat milk fat metabolism. Here we utilized an improved miRNA detection assay, S-Poly-(T, to profile the expression of miRNAs in the goat mammary gland in different periods, and found that miR-130b was abundantly and differentially expressed in goat mammary gland. Additionally, overexpressing miR-130b impaired adipogenesis while inhibiting miR-130b enhanced adipogenesis in goat mammary epithelial cells. Utilizing 3'-UTR assay and Western Blot analusis, the protein peroxisome proliferator-activated receptor coactivator-1α (PGC1α, a major regulator of fat metabolism, was demonstrated to be a potential target of miR-130b. Interestingly, miR-130b potently repressed PGC1α expression by targeting both the PGC1α mRNA coding and 3' untranslated regions. These findings have some insight of miR-130b in mediating adipocyte differentiation by repressing PGC1α expression and this contributes to further understanding about the functional significance of miRNAs in milk fat synthesis.

Increasing human Th17 differentiation through activation of orphan nuclear receptor retinoid acid-related orphan receptor γ (RORγ) by a class of aryl amide compounds.

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Zhang, Wei; Zhang, Jing; Fang, Leiping; Zhou, Ling; Wang, Shuai; Xiang, Zhijun; Li, Yuan; Wisely, Bruce; Zhang, Guifeng; An, Gang; Wang, Yonghui; Leung, Stewart; Zhong, Zhong

2012-10-01

In a screen for small-molecule inhibitors of retinoid acid-related orphan receptor γ (RORγ), we fortuitously discovered that a class of aryl amide compounds behaved as functional activators of the interleukin 17 (IL-17) reporter in Jurkat cells. Three of these compounds were selected for further analysis and found to activate the IL-17 reporter with potencies of ∼0.1 μM measured by EC₅₀. These compounds were shown to directly bind to RORγ by circular dichroism-based thermal stability experiments. Furthermore, they can enhance an in vitro Th17 differentiation process in human primary T cells. As RORγ remains an orphan nuclear receptor, discovery of these aryl amide compounds as functional agonists will now provide pharmacological tools for us to dissect functions of RORγ and facilitate drug discovery efforts for immune-modulating therapies.

Drosophila motor neuron retraction during metamorphosis is mediated by inputs from TGF-β/BMP signaling and orphan nuclear receptors.

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Ana Boulanger

Full Text Available Larval motor neurons remodel during Drosophila neuro-muscular junction dismantling at metamorphosis. In this study, we describe the motor neuron retraction as opposed to degeneration based on the early disappearance of β-Spectrin and the continuing presence of Tubulin. By blocking cell dynamics with a dominant-negative form of Dynamin, we show that phagocytes have a key role in this process. Importantly, we show the presence of peripheral glial cells close to the neuro-muscular junction that retracts before the motor neuron. We show also that in muscle, expression of EcR-B1 encoding the steroid hormone receptor required for postsynaptic dismantling, is under the control of the ftz-f1/Hr39 orphan nuclear receptor pathway but not the TGF-β signaling pathway. In the motor neuron, activation of EcR-B1 expression by the two parallel pathways (TGF-β signaling and nuclear receptor triggers axon retraction. We propose that a signal from a TGF-β family ligand is produced by the dismantling muscle (postsynapse compartment and received by the motor neuron (presynaptic compartment resulting in motor neuron retraction. The requirement of the two pathways in the motor neuron provides a molecular explanation for the instructive role of the postsynapse degradation on motor neuron retraction. This mechanism insures the temporality of the two processes and prevents motor neuron pruning before postsynaptic degradation.

Drosophila motor neuron retraction during metamorphosis is mediated by inputs from TGF-β/BMP signaling and orphan nuclear receptors.

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Boulanger, Ana; Farge, Morgane; Ramanoudjame, Christophe; Wharton, Kristi; Dura, Jean-Maurice

2012-01-01

Larval motor neurons remodel during Drosophila neuro-muscular junction dismantling at metamorphosis. In this study, we describe the motor neuron retraction as opposed to degeneration based on the early disappearance of β-Spectrin and the continuing presence of Tubulin. By blocking cell dynamics with a dominant-negative form of Dynamin, we show that phagocytes have a key role in this process. Importantly, we show the presence of peripheral glial cells close to the neuro-muscular junction that retracts before the motor neuron. We show also that in muscle, expression of EcR-B1 encoding the steroid hormone receptor required for postsynaptic dismantling, is under the control of the ftz-f1/Hr39 orphan nuclear receptor pathway but not the TGF-β signaling pathway. In the motor neuron, activation of EcR-B1 expression by the two parallel pathways (TGF-β signaling and nuclear receptor) triggers axon retraction. We propose that a signal from a TGF-β family ligand is produced by the dismantling muscle (postsynapse compartment) and received by the motor neuron (presynaptic compartment) resulting in motor neuron retraction. The requirement of the two pathways in the motor neuron provides a molecular explanation for the instructive role of the postsynapse degradation on motor neuron retraction. This mechanism insures the temporality of the two processes and prevents motor neuron pruning before postsynaptic degradation.