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  • 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)

  • Morphological studies of prolactin-secreting cells in estrogen receptor alpha and estrogen receptor beta knockout mice. 12806178

    Estrogens play a major role in the regulation of prolactin (PRL) secretion through activation of pituitary and hypothalamic estrogen receptors (ERs). In order to evaluate the relative role of ERalpha and ERbeta in the control of PRL density in the pituitary gland, we performed immunocytochemical localization of PRL and ERs in pituitaries of wild-type (WT), ERalpha knockout (KO) and ERbetaKO mice. In WT and ERbetaKO anterior pituitaries, the vast majority of secretory cells contained ERalpha immunoreactivity, while no ERalpha immunostaining could be found in ERalphaKO pituitaries. No ERbeta immunoreactivity could be detected in pituitaries of WT, ERalphaKO or ERbetaKO mice. At the light microscopic level, a large number of cells staining for PRL were present in pituitaries of female WT, while in female ERalphaKO pituitaries, the density of PRL cells was much lower. In WT male pituitaries, the density of PRL cells was lower than observed in female WT, while PRL staining was markedly decreased in male ERalphaKO as compared to male WT. In ERbetaKO mice of both sexes, the results were identical to those observed in WT animals. At the electron microscopic level, in WT mice of both sexes, type 1 PRL cells exhibited a well-developed Golgi apparatus and a large number of strongly stained large mature and immature secretory granules. Type 2 PRL cells were also present in the pituitary. Type 2 PRL cells contain small poorly labelled granules. In ERalphaKO mice of both sexes, type 1 PRL cells were atrophied with poorly developed Golgi apparatus, and no type 2 PRL cells could be observed. In ERalphaKO pituitaries, typical gonadectomy cells were found. No ultrastructural changes were observed in PRL cells of ERbetaKO mice. The present data strongly suggest that the positive regulation of PRL expression at the pituitary level by estrogens is mediated by ERalpha and does not involve ERbeta activation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo

  • 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

  • Identification of gain-of-function variants of the human prolactin receptor. 21036240

    There is currently no known genetic disease linked to prolactin (PRL) or its receptor (PRLR) in humans. Recently, we identified three missense variants of the PRLR in patients presenting with breast tumors. Two of them (named PRLR(I146L) and PRLR(I76V)) had been reported earlier, but failed to draw much attention because the eventual impact of these substitutions on receptor properties remained unknown. In this chapter, we describe the various bioassays (cell types and readouts) that led to the discovery that both variants exhibit gain-of-function properties. Reconstituted cell models involving Ba/F3, HEK293, and MCF-7 cell lines all highlighted the constitutive, PRL-independent potency of PRLR(I146L) to trigger downstream signaling, leading to antiapoptotic and proliferation properties. The lower level of basal activity of PRLR(I76V) could be demonstrated only in the very sensitive Ba/F3 cell assay. While comparative analysis of ligands is a routine procedure in many labs, comparison of receptor variants de facto imposes the use of different cell clones (or population) in which each receptor variant is expressed individually. This is more delicate, as one must ensure that differences in biological responses really reflect differences in the intrinsic properties of receptor variants, and not any feature of cell clones/populations that are used, which could bias the interpretation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-182

  • Stoichiometric structure-function analysis of the prolactin receptor signaling domain by receptor chimeras. 9447986

    The intracellular domain of the prolactin (PRL) receptor (PRLr) is required for PRL-induced signaling and proliferation. To identify and test the functional stoichiometry of those PRLr motifs required for transduction and growth, chimeras consisting of the extracellular domain of either the alpha or beta subunit of human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor (GM-CSFr) and the intracellular domain of the rat PRLr were synthesized. Because the high-affinity binding of GM-CSF results from the specific pairing of one alpha- and one beta-GM-CSFr, use of GM-CSFr/PRLr chimera enabled targeted dimerization of the PRLr intracellular domain. To that end, the extracellular domains of the alpha- and beta-GM-CSFr were conjugated to one of the following mutations: (i) PRLr C-terminal truncations, termed alpha278, alpha294, alpha300, alpha322, or beta322; (ii) PRLr tyrosine replacements, termed Y309F, Y382F, or Y309+382F; or, (iii) PRLr wild-type short, intermediate, or long isoforms. These chimeras were cotransfected into the cytokine-responsive Ba/F3 line, and their expression was confirmed by ligand binding and Northern and Western blot analyses. Data from these studies revealed that heterodimeric complexes of the wild type with C-terminal truncation mutants of the PRLr intracellular domain were incapable of ligand-induced signaling or proliferation. Replacement of any single tyrosine residue (Y309F or Y382F) in the dimerized PRLr complex resulted in a moderate reduction of receptor-associated Jak2 activation and proliferation. In contrast, trans replacement of these residues (i.e., alphaY309F and betaY382F) markedly reduced ligand-driven Jak2 activation and proliferation, while cis replacement of both tyrosine residues in a single intracellular domain (i.e., alphaY309+382F) produced an inactive signaling complex. Analysis of these GM-CSFr-PRLr complexes revealed equivalent levels of Jak2 in association with the mutant receptor chains, suggesting that the tyrosine residues at 309 and 382 do not contribute to Jak association, but instead to its activation. Heterodimeric pairings of the intracellular domains from the known PRLr receptor isoforms (short-intermediate, short-long, and intermediate-long) also yielded inactive receptor complexes. These data demonstrate that the tyrosine residues at 309 and 382, as well as additional residues within the C terminus of the dimerized PRLr complex, contribute to PRL-driven signaling and proliferation. Furthermore, these findings indicate a functional requirement for the pairing of Y309 and Y382 in trans within the dimerized receptor complex.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-255
    Nombre del producto:
    Anti-JAK2 Antibody

  • High expression of prolactin receptor is associated with cell survival in cervical cancer cells. 24148306

    The altered expression of prolactin (PRL) and its receptor (PRLR) has been implicated in breast and other types of cancer. There are few studies that have focused on the analysis of PRL/PRLR in cervical cancer where the development of neoplastic lesions is influenced by the variation of the hormonal status. The aim of this study was to evaluate the expression of PRL/PRLR and the effect of PRL treatment on cell proliferation and apoptosis in cervical cancer cell lines.High expression of multiple PRLR forms and PRLvariants of 60-80 kDa were observed in cervical cancer cell lines compared with non-tumorigenic keratinocytes evaluated by Western blot, immunofluorecence and real time PCR. Treatment with PRL (200 ng/ml) increased cell proliferation in HeLa cells determined by the MTT assay at day 3 and after 1 day a protective effect against etoposide induced apoptosis in HeLa, SiHa and C-33A cervical cancer cell lines analyzed by the TUNEL assay.Our data suggests that PRL/PRLR signaling could act as an important survival factor for cervical cancer. The use of an effective PRL antagonist may provide a better therapeutic intervention in cervical cancer.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1501
    Nombre del producto:
    Anti-Actin Antibody, clone C4

  • Prolactin potentiates insulin-stimulated leptin expression and release from differentiated brown adipocytes. 15591027

    The pituitary hormone prolactin (PRL) exerts pleiotropic effects, which are mediated by a membrane receptor (PRLR) present in numerous cell types including adipocytes. Brown adipose tissue (BAT) expresses uncoupling proteins (UCPs), involved in thermogenesis, but also secretes leptin, a key hormone involved in the control of body weight. To investigate PRL effects on BAT, we used the T37i brown adipose cell line, and demonstrated that PRLRs are expressed as a function of cell differentiation. Addition of PRL leads to activation of the JAK/STAT and MAP kinase signaling pathways, demonstrating that PRLRs are functional in these cells. Basal and catecholamine-induced UCP1 expression were not affected by PRL. However, PRL combined with insulin significantly increases leptin expression and release, indicating that PRL potentiates the stimulatory effect of insulin as revealed by the recruitment of insulin receptor substrates and the activation of phosphatidylinositol 3-kinase. To explore the in vivo physiological relevance of PRL action in BAT, we showed that leptin content was significantly increased in BAT of PRLR-null mice compared with wild-type mice, highlighting the involvement of PRL in the leptin secretion process. This study provides the first evidence for a functional link between PRL and energy balance via a cross-talk between insulin and PRL signaling pathways in brown adipocytes.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-255
    Nombre del producto:
    Anti-JAK2 Antibody

  • Noradrenergic nuclei that receive sensory input during mating and project to the ventromedial hypothalamus play a role in mating-induced pseudopregnancy in the female rat ... 20673300

    In female rats, vaginal-cervical stimulation (VCS) received during mating induces bicircadian prolactin surges that are required for the maintenance of pregnancy or pseudopregnancy (PSP). The neural circuits that transmit VCS inputs to the brain have not been fully described, although mating stimulation is known to activate medullary noradrenergic cell groups that project to the forebrain. In response to VCS, these neurones release noradrenaline within the ventrolateral division of the ventromedial hypothalamus (VMHvl) and the posterodorsal medial amygdala (MePD), two forebrain sites that are implicated in the initiation of PSP. Noradrenaline receptor activation within the VMHvl is both necessary and sufficient for PSP induction, suggesting that noradrenaline acting within the VMHvl is particularly important in mediating the effects of VCS towards the establishment of PSP. We therefore investigated whether or not endogenous, VCS-induced noradrenaline release within the VMHvl is involved in PSP induction in the rat. Before the receipt of sufficient mating stimulation to induce PSP, a retrograde neurotoxin, dopamine-β-hydroxylase-saporin (DBH-SAP), was infused bilaterally into the either the VMHvl or the MePD to selectively destroy afferent noradrenergic nuclei in the brainstem. DBH-SAP infusions into the VMHvl lesioned mating-responsive noradrenergic neurones in A1 and A2 medullary nuclei and reduced the incidence of PSP by 50%. Infusions of DBH-SAP into the MePD had no effect on the subsequent induction of PSP. These results suggest that VCS is conveyed to mating-responsive forebrain areas by brainstem noradrenergic neurones, and that the activity of noradrenergic cells projecting to the VMHvl is involved in the induction of PSP.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • CUZD1 is a critical mediator of the JAK/STAT5 signaling pathway that controls mammary gland development during pregnancy. 28278176

    In the mammary gland, genetic circuits controlled by estrogen, progesterone, and prolactin, act in concert with pathways regulated by members of the epidermal growth factor family to orchestrate growth and morphogenesis during puberty, pregnancy and lactation. However, the precise mechanisms underlying the crosstalk between the hormonal and growth factor pathways remain poorly understood. We have identified the CUB and zona pellucida-like domain-containing protein 1 (CUZD1), expressed in mammary ductal and alveolar epithelium, as a novel mediator of mammary gland proliferation and differentiation during pregnancy and lactation. Cuzd1-null mice exhibited a striking impairment in mammary ductal branching and alveolar development during pregnancy, resulting in a subsequent defect in lactation. Gene expression profiling of mammary epithelium revealed that CUZD1 regulates the expression of a subset of the EGF family growth factors, epiregulin, neuregulin-1, and epigen, which act in an autocrine fashion to activate ErbB1 and ErbB4 receptors. Proteomic studies further revealed that CUZD1 interacts with a complex containing JAK1/JAK2 and STAT5, downstream transducers of prolactin signaling in the mammary gland. In the absence of CUZD1, STAT5 phosphorylation in the mammary epithelium during alveologenesis was abolished. Conversely, elevated expression of Cuzd1 in mammary epithelial cells stimulated prolactin-induced phosphorylation and nuclear translocation of STAT5. Chromatin immunoprecipitation confirmed co-occupancy of phosphorylated STAT5 and CUZD1 in the regulatory regions of epiregulin, a potential regulator of epithelial proliferation, and whey acidic protein, a marker of epithelial differentiation. Collectively, these findings suggest that CUZD1 plays a critical role in prolactin-induced JAK/STAT5 signaling that controls the expression of key STAT5 target genes involved in mammary epithelial proliferation and differentiation during alveolar development.
    Tipo de documento:
    Referencia
    Referencia del producto:
    17-371
    Nombre del producto:
    EZ-ChIP™

  • Role of c-Myb during prolactin-induced signal transducer and activator of transcription 5a signaling in breast cancer cells. 19036881

    Implicated in the pathogenesis of breast cancer, prolactin (PRL) mediates its function in part through the prolactin receptor (PRLr)-associated Janus kinase 2 (Jak2)/signal transducer and activator of transcription 5 (Stat5) signaling complex. To delineate the mechanisms of Stat5a regulation in breast cancer, transcription factor-transcription factor (TF-TF) array analysis was employed to identify associated transcriptional regulators. These analyses revealed a PRL-inducible association of Stat5a with the transcription factor and protooncogene c-Myb. Confirmatory co-immunoprecipitation studies using lysates from both T47D and MCF7 breast cancer cells revealed a PRL-inducible association between these transcription factors. Ectopic expression of c-Myb enhanced the PRL-induced expression from both composite and synthetic Stat5a-responsive luciferase reporters. Chromatin immunoprecipitation assays also revealed a PRL-inducible association between c-Myb and endogenous Stat5a-responsive CISH promoter, which was associated with an enhanced expression of CISH gene product at the RNA and protein levels. Small interfering RNA-mediated c-Myb knockdown impaired the PRL-induced mRNA expression of five Stat5-responsive genes. DNA binding-defective mutants of c-Myb, incapable of activating expression from a c-Myb-responsive reporter, maintained their ability to enhance a Stat5a-responsive reporter. At a cellular level, ectopic expression of c-Myb resulted in an increase in T47D proliferation. Taken together, these results indicate that c-Myb potentiates Stat5a-driven gene expression, possibly functioning as a Stat5a coactivator, in human breast cancer.
    Tipo de documento:
    Referencia
    Referencia del producto:
    17-371
    Nombre del producto:
    EZ-ChIP™