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  • 1,25-Dihydroxyvitamin D3 regulates the expression of low-density lipoprotein receptor-related protein 5 via deoxyribonucleic acid sequence elements located downstream of ... 16613987

    The skeleton is a direct target of vitamin D action, where the hormone modulates the proliferation of osteoblast precursors, their differentiation into mature osteoblasts, and their functional activity. Some of these effects of vitamin D are reminiscent of those orchestrated by the Wnt signaling pathway wherein stimulation of the membrane receptor Frizzled and its coreceptor LRP5 leads to activation of beta-catenin and subsequent transcription-mediated changes in osteoblast biology. Indeed, LRP5 is now known to play a particularly important role in bone formation such that the loss of this component results in a reduction in osteoblast number, a delay in mineralization, and a reduction in peak bone mineral density. Interestingly, we discovered during the course of a vitamin D receptor (VDR) chromatin immunoprecipitation/DNA microarray analysis that 1,25-(OH)2D3 could induce binding of the VDR to sites within the Lrp5 gene locus. VDR and retinoid X receptor binding was evident both in primary osteoblasts as well as in osteoblasts of cell line origin. Importantly, this interaction between 1,25-(OH)2D3-activated VDR and the Lrp5 gene led to both a modification in chromatin structure within the Lrp5 locus and the induction of Lrp5 mRNA transcripts in vivo as well as in vitro. One of these sites within the Lrp5 locus was discovered to confer vitamin D response to a heterologous promoter when introduced into osteoblastic cells, permitting both the identification and characterization of the vitamin D response element located within. Interestingly, additional studies revealed that whereas the regulatory region in the mouse Lrp5 gene was highly conserved in the human genome, the vitamin D response element was not. Our studies show that 1,25-(OH)2D3 can enhance the expression of a critical component of the Wnt signaling pathway that is known to impact osteogenesis.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-866
    Nombre del producto:
    Anti-acetyl-Histone H4 Antibody

  • Prolactin-induced activation of phagocyte NADPH oxidase in the teleost fish gilthead seabream involves the phosphorylation of p47phox by protein kinase C. 21884725

    The pituitary hormone prolactin (PRL) is a multifunctional polypeptide which act as a key component of the neuroendocrine-immune loop and as a local regulator of the macrophage response. The involvement of PRL in regulating monocyte/macrophage functions is suggested by the presence of PRL receptors in these cells. Recently, we reported that physiological concentrations of native PRL were able to induce the expression of the pro-inflammatory cytokines IL-1? and TNF?, and the production of reactive oxygen species (ROS) in head kidney leukocytes and macrophages from the teleost fish gilthead seabream (Sparus aurata L.). In this study, we show that the NADPH oxidase subunit p47phox becomes phosphorylated in leukocytes stimulated with PRL, an effect that is blocked when neutralizing polyclonal antibodies to PRL are added. Additionally, the pharmacological inhibition of either protein kinase C (PKC) with calphostin C or the Jak/Stat signaling pathway with AG490 impaired PKC activation, p47phox phosphorylation and ROS production in seabream leukocytes activated with PRL. Taken together, our results demonstrate for the first time the need for PKC in regulating the PRL-mediated phosphorylation of p47phox, the activation of NADPH oxidase and the production of ROS by macrophages in vertebrates.
    Tipo de documento:
    Referencia
    Referencia del producto:
    05-1050
    Nombre del producto:
    4G10® Platinum, Anti-Phosphotyrosine Antibody (mouse monoclonal cocktail IgG2b)

  • Thyroid hormone-mediated negative transcriptional regulation of Necdin expression. 16720720

    Unliganded thyroid hormone receptors (apoTRs) repress transcription of hormone-activated genes by recruiting corepressors to the promoters. In contrast, on promoters containing so-called negative thyroid hormone response elements (nTREs), apoTRs activate transcription. A number of different molecular mechanisms have been described as to how apoTRs activate transcription varying with the target gene of the study. Here we demonstrate that thyroid hormone regulates the transcription of the Necdin gene, a developmentally regulated candidate gene for the genomic imprinting-associated neurobehavioural disorder, Prader-Willi syndrome. ApoTRs activate Necdin expression through an nTRE in its promoter, downstream of the transcription start site. The nTRE of the Necdin gene resembles the nTREs of the TSHbeta genes of the hypothalamus-pituitary-thyroid axis in the sequence, position in the promoter, and mode of activation. We show that this group of nTRE-driven genes shares the requirements for binding of the retinoic X receptor and nuclear receptor corepressor/silencing mediator of retinoid and thyroid hormone receptors (NCoR/SMRT) for full ligand-independent activation, whereas there is no need for association of the p160 family of coactivators. In accordance with the requirement for corepressors, Necdin expression is influenced by deacetylase activity, suggesting that histone deacetylases and corepressors as well could function as activators of transcription, depending on the promoter context.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Progesterone potentiates calcium release through IP3 receptors by an Akt-mediated mechanism in hippocampal neurons. 19081133

    Progesterone (P4) is a steroid hormone that plays multiple roles in the central nervous system (CNS) including promoting neuroprotection. However, the precise mechanisms involved in its neuroprotective effects are still unknown. Given that the regulation of the intracellular calcium (Ca(2+)) concentration is critical for cell survival, we determined if inositol 1, 4, 5-trisphosphate receptors (IP(3)Rs) are relevant targets of P4. Using primary hippocampal neurons, we tested the hypothesis that P4 controls the gain of IP3R-mediated intracellular Ca(2+) signaling in neurons and characterized the subcellular distribution and phosphorylation of potential signaling intermediates involved in P4s actions. Our results reveal that P4 treatment altered the intensity and distribution of IP3R immunoreactivity and induced the nuclear translocation of phosphorylated Akt. Further, P4 potentiated IP(3)R-mediated intracellular Ca(2+) responses. These results suggest a potential involvement of P4 in particular and of steroid hormone signaling pathways in general in the control of intracellular Ca(2+) signaling and its related functions.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Glucagon-like peptide-1 (GLP-1) induces M2 polarization of human macrophages via STAT3 activation. 22842565

    It is known that glucagon-like peptide-1 (GLP-1) is a hormone secreted postprandially from the L-cells of the small intestine and regulates glucose homeostasis. GLP-1 is now used for the treatment of diabetes because of its beneficial role against insulin resistance. The GLP-1 receptor (GLP-1R) is expressed on many cell types, including macrophages, and GLP-1 suppresses the development of atherosclerosis by inhibiting macrophage function. However, there have so far been few studies that have investigated the significance of GLP-1/GLP-1R signaling in macrophage activation. In the present study, we examined the effect of GLP-1 and exenatide, a GLP-1R agonist, on human monocyte-derived macrophage (HMDM) activation. We found that GLP-1 induced signal transducer and activator of transcription 3 (STAT3) activation. Silencing of GLP-1R suppressed the GLP-1-induced STAT3 activation. In addition, alternatively activated (M2) macrophage-related molecules, such as IL-10, CD163, and CD204 in HMDM, were significantly upregulated by GLP-1. Furthermore, the co-culture of 3T3-L1 adipocytes with GLP-1-treated RAW 264.7 macrophages increased the secretion of adiponectin compared to co-culture of the 3T3-L1 adipocytes with untreated RAW 264.7 macrophages. Our results demonstrate that GLP-1 induces macrophage polarization toward the M2 phenotype, which may contribute to the protective effects of GLP-1 against diabetes and cardiovascular diseases.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB3608

  • A study of somatolactin actions by ectopic expression in transgenic zebrafish larvae. 20801895

    Somatolactin (SL) is a fish-specific hormone that belongs to the prolactin (PRL) and GH family. Recently, two forms of SL, SL? and SL?, have been found in some species, and may have different actions and functions. To investigate the role of SL in fish growth and metabolism, we generated transgenic fish founders with ectopic expression of SL? and SL? to study the physiological functions and actions of these SLs among several marker genes. We fused the cDNAs encoding the precursor SLs in frame to a zebrafish ?-actin gene promoter to generate transgenic zebrafish lines that were coinjected with a green fluorescent protein (GFP) driven by the same promoter. The transgenic zebrafish were selected based on GFP expression and confirmed by genomic PCR, Southern blot analysis, and transgene expression. Investigations into the expression of marker genes in larvae on different pathways using real-time PCR have provided a general understanding of the actions of SLs. This study found that the overexpression of SL? and SL? in vivo significantly enhanced the transcription of IGFs, insulin, leptin, sterol regulatory element binding protein 1, and fatty acid synthase, as well as the expression level of vitellogenin and proopiomelanocortin, while causing reduced levels of catalase and glutathione S-transferase in the larvae of transgenic zebrafish.
    Tipo de documento:
    Referencia
    Referencia del producto:
    09-142
    Nombre del producto:
    Anti-phospho-ACK1 (Tyr284) Antibody

  • Peptide hormone isoforms: N-terminally branched PYY3-36 isoforms give improved lipid and fat-cell metabolism in diet-induced obese mice. 20853314

    The prevalence of obesity is increasing with an alarming rate worldwide and there is a need for efficacious satiety drugs. PYY3-36 has been shown to play a role in hypothalamic appetite regulation and novel analogs targeting the Y2 receptor have potential as drugs for the treatment of obesity. We have designed a series of novel PYY3-36 isoforms, by first adding the dipeptide Ile-Lys N-terminal to the N(?) of Ser-13 in PYY13-36 and then anchoring the N-terminal segment, e.g. PYY3-12, to the new Lys N(?)-amine. We hypothesized that such modifications would alter the folding of PYY, due to changes in the turn motif, which could change the binding mode to the Y receptor sub-types and possibly also alter metabolic stability. In structure-affinity/activity relationship experiments, one series of PYY isoforms displayed equipotency towards the Y receptors. However, an increased Y2 receptor potency for the second series of PYY isoforms resulted in enhanced Y receptor selectivity compared to PYY3-36. Additionally, acute as well as chronic mice studies showed body-weight-lowering effects for one of the PYY isoforms, which was also reflected in a reduction of circulating leptin levels. Interestingly, while the stability and pharmacokinetic profile of PYY3-36 and the N-terminally modified PYY3-36 analogue were identical, only mice treated with the branched analogue showed marked increases in adiponectin levels as well as reductions in non-esterified free fatty acids and triglycerides.
    Tipo de documento:
    Referencia
    Referencia del producto:
    EZML-82K
    Nombre del producto:
    Mouse Leptin ELISA

  • A rapid method for the preparation of 125I-labelled human growth hormone for receptor studies, using reverse-phase high performance liquid chromatography. 3004459

    Human growth hormone was labelled with 125 Iodine by the stoichiometric modification of the chloramine-T method to a specific activity of 50-80 microCi/microgram, and the iodinated mixture was purified by reverse-phase high performance liquid chromatography using a C18 column (SynChropak RP-P) and a linear gradient. Compared with the usual Sephadex G-100 chromatography, HPLC gave a much better separation, with a higher yield and a considerably reduced analysis time (30 min vs 5 h). The [125I]-labelled preparation had normal binding to IM-9 lymphocyte receptors. The maximum bindability of the HPLC-purified preparation approximated 90%, which is the best value so far reported for human growth hormone. It is concluded that HPLC is a fast, convenient and reproducible method for obtaining an improved [125I]-labelled human growth hormone for receptor studies.
    Tipo de documento:
    Referencia
    Referencia del producto:
    17-191
    Nombre del producto:
    MAP Kinase/Erk Assay Kit, non-radioactive

  • Prepubertal estrogen exposure modifies neurotrophin receptor expression in celiac neurons and alters ovarian innervation. 19036644

    Estradiol is a key hormone in the regulation of reproductive processes acting both on peripheral organs and sympathetic neurons associated to reproductive function. However, many of its regulatory effects on the development and function on the sympathetic neurons have not been completely clarified. Sympathetic neurons located in the celiac ganglion projects to visceral, vascular and glandular targets, and contribute to ovarian innervation, being the main source of sympathetic fibers. In the present study, we analyze the effects of elevated levels of exogenous estrogen during the prepubertal period in post-ganglionic sympathetic neurons. Estrogen exposure induced a significant increase in sympathetic celiac neuronal size and modified the expression of neurotrophin receptor p75. This change affected mainly small and medium size neurons. The effect of estrogens on innervation of celiac target organs was heterogeneous, inducing a significant increase in catecholaminergic innervation of the ovary, but not of the pyloric muscular layers. These findings further support the role of estrogen as a modulator of neuronal plasticity and suggest that estrogen could modify some features involved in the relation between sympathetic immature peripheral neurons and their target organs throughout a neurotrophin-dependent mechanism.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB365
    Nombre del producto:
    Anti-Nerve Growth Factor Receptor Antibody, extracellular, clone 192-IgG

  • Transcriptional regulation of the human NRIP1/RIP140 gene by estrogen is modulated by dioxin signalling. 16391242

    Receptor interacting protein 140 (RIP140) is a negative transcriptional regulator of nuclear hormone receptors that is required for the maintenance of energy homeostasis and ovulation. In this study, we investigated the mechanisms by which RIP140 expression is controlled by estrogens in breast cancer cells. We first analyzed by real time reverse transcription-polymerase chain reaction the regulation of RIP140 mRNA accumulation by estrogen receptor (ER) ligands in MCF-7 cells. We showed that the induction by estradiol (E2) was rapid and did not affect the apparent stability of the mRNA, suggesting a direct transcriptional regulation. To further study the underlying regulatory mechanisms, we then characterized the human RIP140 gene. We identified several noncoding exons with alternative splicing and localized the promoter region more than 100 kilobases upstream from the coding exon. Although we mapped a perfect consensus estrogen response element able to bind ERalpha in gel shift and in chromatin immunoprecipitation experiments, the effect of E2 on RIP140 gene transcription was very modest. This might result at least in part from the presence of an overlapping aryl hydrocarbon receptor (AhR) binding site, which interfered with the E2 response on both the transiently transfected reporter construct and the accumulation of the endogenous RIP140 mRNA. Altogether, our data indicate that the RIP140 gene exhibits a complex structure with several noncoding exons and supports transcriptional cross-talk and feedback involving the ERalpha and AhR nuclear receptors.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-942
    Nombre del producto:
    Anti-acetyl-Histone H3 (Lys9) Antibody