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The Journal of Endocrinology Feb 2011Atherosclerotic vascular disease is the consequence of a chronic inflammatory process, and prolactin has been shown to be a component of the inflammatory response....
Atherosclerotic vascular disease is the consequence of a chronic inflammatory process, and prolactin has been shown to be a component of the inflammatory response. Additionally, recent studies indicate that prolactin contributes to an atherogenic phenotype. We hypothesized that this may be the result of a direct effect of prolactin on atherogenesis through activation of the prolactin receptor. Human carotid atherosclerotic plaques were obtained from patients by endarteriectomies. The mRNA of prolactin receptor, but not of prolactin, was detected in these atherosclerotic plaques by quantitative real-time PCR. In situ hybridization confirmed the expression of the prolactin receptor in mononuclear cells. Analysis at the protein level using immunohistochemistry and immunoelectron microscopy revealed that the prolactin receptor was abundantly present in macrophages near the lipid core and shoulder regions of the plaques. Our findings demonstrate that the prolactin receptor is present in macrophages of the atherosclerotic plaque at sites of most prominent inflammation. We therefore propose that prolactin receptor signaling contributes to the local inflammatory response within the atherosclerotic plaque and thus to atherogenesis.
Topics: Atherosclerosis; Carotid Artery Diseases; Carotid Stenosis; Computer Systems; Female; Humans; Immunohistochemistry; In Situ Hybridization; Inflammation; Inflammation Mediators; Macrophages; Male; Microscopy, Immunoelectron; Polymerase Chain Reaction; Prolactin; RNA, Messenger; Receptors, Prolactin; Signal Transduction; Tissue Distribution
PubMed: 21068074
DOI: 10.1677/JOE-10-0076 -
Journal of Neuroendocrinology Apr 1994Prolactin receptors may mediate the action of prolactin in the brain to influence behavior and neuroendocrine secretions. We recently demonstrated prolactin receptor...
Prolactin receptors may mediate the action of prolactin in the brain to influence behavior and neuroendocrine secretions. We recently demonstrated prolactin receptor gene expression in the anterior and medial basal hypothalamus and not in the cortex by the reverse transcription-polymerase chain reaction. In this paper, we localize the prolactin receptor gene expression to individual cells with in situ hybridization. Several steps in the in situ hybridization method were modified to increase sensitivity by using (i) probes complementary to the coding sequence of the extracellular binding domain common to both long and short prolactin receptor, (ii) more stringent hybridization and wash conditions to reduce background and (iii) higher specific activity, more complex and saturating amounts of probe. We detected prolactin receptor gene expression in cells of the periventricular area of the preoptic nucleus, medial preoptic nucleus, supraoptic nucleus, rostral arcuate nucleus and choroid plexus. Cortical brain tissue, which has been demonstrated previously by reverse-transcription polymerase chain reaction to be lacking in prolactin receptor mRNA, did not have any detectable signal for the receptor mRNA and was used as an indication of background levels of signal. The mean area of silver grains over labeled cells in periventricular area of the preoptic nucleus, medial preoptic nucleus, supraoptic nucleus, arcuate nucleus, lateral ventromedial nucleus was at least 10 times greater than the background in the cortex of the same brain section.
Topics: Animals; Female; Gene Expression; Hypothalamus; In Situ Hybridization; Polymerase Chain Reaction; RNA Probes; RNA, Messenger; Rats; Rats, Sprague-Dawley; Receptors, Prolactin; Silver Staining
PubMed: 8049718
DOI: 10.1111/j.1365-2826.1994.tb00572.x -
Journal of Cell Science May 1997Prolactin (PRL) interacts with a specific, well characterized plasma membrane receptor (PRLR) that is coupled to signal transduction pathways involving Jak2, Fyn, and...
Prolactin (PRL) interacts with a specific, well characterized plasma membrane receptor (PRLR) that is coupled to signal transduction pathways involving Jak2, Fyn, and MAP kinases, and signal transducers and activators of transcription (STAT). Although a few previous studies have indicated nuclear translocation of PRL in IL-2 stimulated T lymphocytes, PRL-dependent Nb2 lymphoma cell lines and 235-1 lactotrophs, the mechanisms of nuclear targeting remain unknown and conflicting results have been reported concerning the putative nuclear translocation of the PRLR. We therefore decided to investigate nuclear translocation of PRLR and PRL in various cell lines transfected with an expression plasmid encoding PRLR, using confocal laser microscopy. We have constructed various cDNAs of the long and short forms of the rat PRLR containing an oligonucleotide encoding a Flag epitope inserted either just before the N-terminal amino acid or in the C-terminal end of the mature receptor (named N-terminal or C-terminal Flag-tagged PRLR). The corresponding receptors function as the PRLR in transfected cells: they are expressed at the plasma membrane and in compartments of the secretory pathway, they bind PRL with normal affinity (Kd= 4x10(-10) M) and have the same capacity to stimulate the transcriptional activity of a milk protein (beta-casein) gene as wild-type PRLR. In addition, the tagged receptors are much more efficiently immunodetected using anti-Flag antibodies, as compared to anti-PRL antibodies (U5 or U6). Immunofluorescence combined with detailed confocal laser microscopy showed that addition of PRL (0 to 12 hours) to COS-7, CHO and NIH-3T3 transfected fibroblasts induces rapid internalization of the receptor (long form), without any translocation to the nucleus. Using PRL-R tagged both in the N-terminal or C-terminal regions of the mature receptor excludes the possibility of a cleaved fragment which could have been subsequently imported into the nucleus. An absence of nuclear translocation of PRLR was also observed in a 293 cell line stably expressing the receptor, and in physiological targets for PRL, i.e. in Nb2 lymphoma cells expressing the Nb2 form of the receptor or in BGME mammary gland epithelial cells upon overexpression of a Flag-tagged PRLR. Similarly, the short form of the PRLR was not detected in nuclei of transfected COS cells upon PRL treatment. Clearly, our results provide evidence that internalization of the plasma membrane PRLR does not lead to nuclear translocation of the receptor, or part of it, in most fibroblasts and epithelial cells at physiological concentrations of PRL. Also, in co-localization experiments, PRL was internalized without nuclear translocation. Activation of STATs transcription factors and MAP kinases, as well as translocation of these proteins to the nucleus following their phosphorylation, probably remains the intracellular mechanism coupling stimulation to nuclear events.
Topics: 3T3 Cells; Animals; Biological Transport; COS Cells; Cattle; Cell Nucleus; DNA, Complementary; Fluorescent Antibody Technique; Gene Expression; Ligands; Mammary Glands, Animal; Mice; Microscopy, Confocal; Mutagenesis; Prolactin; Rats; Receptors, Prolactin; Transfection
PubMed: 9175708
DOI: 10.1242/jcs.110.9.1123 -
Oncotarget Nov 2016Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in humans and is characterized with poor outcome. In this study, we investigated...
Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in humans and is characterized with poor outcome. In this study, we investigated components of prolactin (Prl) system in cell models of GBM and in histological tissue sections obtained from GBM patients. Expression of Prolactin receptor (PrlR) was detected at high levels in U251-MG, at low levels in U87-MG and barely detectable in U373 cell lines and in 66% of brain tumor tissues from 32 GBM patients by immunohistochemical technique. In addition, stimulation of U251-MG and U87-MG cells but not U373 with Prl resulted in increased STAT5 phosphorylation and only in U251-MG cells with increased cellular invasion. Furthermore, STAT5 phosphorylation and cellular invasion induced in Prl stimulated cells were significantly reduced by using a Prl receptor antagonist that consists of Prl with four amino acid replacements. We conclude that Prl receptor is expressed at different levels in the majority of GBM tumors and that blocking of PrlR in U251-MG cells significantly reduce cellular invasion.
Topics: Antineoplastic Agents, Hormonal; Brain Neoplasms; Cell Line, Tumor; Cell Movement; Dose-Response Relationship, Drug; Glioblastoma; Hormone Antagonists; Humans; Neoplasm Invasiveness; Phosphorylation; Prolactin; Receptors, Prolactin; STAT5 Transcription Factor; Signal Transduction
PubMed: 27788487
DOI: 10.18632/oncotarget.12840 -
The Oncologist May 2016In this issue of , Agarwal et al. report negative results from a phase I trial of LFA102. Although “negative” in terms of antitumor activity, the study provides...
In this issue of , Agarwal et al. report negative results from a phase I trial of LFA102. Although “negative” in terms of antitumor activity, the study provides useful pharmacokinetic and pharmacodynamic information. Future trials evaluating PRLR blockers alone and in combination with other agents may still be warranted in patients with breast and prostate cancer.
Topics: Breast Neoplasms; Humans; Male; Prolactin; Prostatic Neoplasms; Receptors, Prolactin; Signal Transduction
PubMed: 27107001
DOI: 10.1634/theoncologist.2016-0108 -
Biology of Reproduction Jun 1995To identify target cells of prolactin (PRL) in the male gonad, the expression of prolactin receptor (PRL-R) mRNA in adult rat testes was investigated by in situ...
To identify target cells of prolactin (PRL) in the male gonad, the expression of prolactin receptor (PRL-R) mRNA in adult rat testes was investigated by in situ hybridization using a digoxigenin-labeled cRNA probe. We also investigated PRL binding to testicular cells in vitro. Signals for PRL-R mRNA were detected not only in interstitial cells but also in spermatogenic cells. Although the reaction was positive in all phases of spermatogonia and spermatocytes, it disappeared in early round spermatids. No signals were detected in elongated spermatids or spermatozoa. The signal intensity varied among each phase of spermatogenic cells. PRL-R mRNA was expressed in all stages of the cycle of the seminiferous epithelium. PRL-R were detected on the surface of Leydig cells, Sertoli cells, all phases of spermatogonia and spermatocytes, elongated spermatids, and spermatozoa. Ovine PRL. did not bind to round spermatids. In Leydig cells, pachytene spermatocytes, and spermatozoa, PRL-R were observed in relatively large numbers. There were fewer receptors in other phases of spermatogenic cells. These results indicate that PRL-R mRNA expression is almost consistent with PRL binding sites except for elongated spermatids and spermatozoa, and suggest that PRL may have direct effects on spermatogenic cells.
Topics: Animals; Digoxigenin; Endothelium; Gene Expression; In Situ Hybridization; Leydig Cells; Male; Prolactin; RNA, Complementary; RNA, Messenger; Rats; Rats, Wistar; Receptors, Prolactin; Sertoli Cells; Spermatids; Spermatocytes; Spermatogenesis; Spermatogonia; Spermatozoa
PubMed: 7632836
DOI: 10.1095/biolreprod52.6.1284 -
European Journal of Histochemistry : EJH Jan 2019Prolactin (PRL) production in mammals has been demonstrated in extrapituitary gland, which can activate autocrine/paracrine signaling pathways to regulate physiological...
Prolactin (PRL) production in mammals has been demonstrated in extrapituitary gland, which can activate autocrine/paracrine signaling pathways to regulate physiological activity. In the current study, we characterized the gene expression profiles of PRL, prolactin receptor (PRLR) and signal transducers and activators of transcription 5 (STAT5) in the scented glandular tissues of the muskrats, to further elucidate the relationship between PRL and the scented glandular functions of the muskrats. The weight and volume of the scented glands in the breeding season were significantly higher than those of the non-breeding season. Immunohistochemical data showed that PRL, PRLR and STAT5/phospho-STAT5 (pSTAT5) were found in the glandular and epithelial cells of the scented glands in both seasons. Furthermore, we found that PRL, PRLR and STAT5 had higher immunoreactivities in the scented glands during the breeding season when compared to those of the non-breeding season. In parallel, the gene expressions of PRL, PRLR and STAT5 were significantly higher in the scented glands during the breeding season than those of the non-breeding season. The concentrations of PRL in scented glandular tissues and sera were measured by enzyme-linked immunosorbent assay (ELISA), and their levels were both notably higher in the breeding season than those of the non-breeding season. These findings suggested that the scented glands of the muskrats were capable of extrapituitary synthesis of PRL, which might attribute PRL a specific function to an endocrine or autocrine/paracrine mediator.
Topics: Animals; Arvicolinae; Gene Expression Regulation; Immunohistochemistry; Male; Prolactin; RNA, Messenger; Receptors, Prolactin; Reproduction; STAT5 Transcription Factor; Scent Glands; Seasons
PubMed: 30652434
DOI: 10.4081/ejh.2019.2991 -
Reproductive Biomedicine Online Mar 2005Prolactin was first identified as an anterior pituitary lobe hormone, responsible for the regulation of mammary gland growth and development. Prolactin receptors have...
Prolactin was first identified as an anterior pituitary lobe hormone, responsible for the regulation of mammary gland growth and development. Prolactin receptors have been localized in a number of peripheral tissues, including tissues involved in reproduction. Studies with knockout animals have shown that prolactin receptor deficient mice present reproductive defects, whereas prolactin promotes the developmental potential of preimplantation mouse and rat embryos in vitro. To better understand the role of prolactin in the process of reproduction and early embryo development in mice, the expression of the four transcript variants of prolactin receptor was examined in the first stages of mouse embryo development. Prolactin long receptor mRNA was expressed in all stages examined, that is in cumulus cells, oocytes, zygotes, 2-cell embryos, 4-cell embryos, morulae and blastocysts. Prolactin receptor type S1 mRNA was observed only in cumulus cells, while S2 mRNA was present in cumulus cells, oocytes, zygotes and 2-cell embryos. S3 mRNA was expressed only in cumulus cells and oocytes. These results indicate that different isoforms of prolactin receptors may be present in the various stages of mouse preimplantation embryo and may play an important role in the control of its growth and development.
Topics: Animals; Base Sequence; Blastocyst; Cleavage Stage, Ovum; DNA; Female; Gene Expression Regulation, Developmental; Male; Mice; Mice, Inbred NZB; Morula; Oocytes; Protein Isoforms; RNA, Messenger; Rats; Receptors, Prolactin; Reverse Transcriptase Polymerase Chain Reaction; Zygote
PubMed: 15820039
DOI: 10.1016/s1472-6483(10)61793-2 -
Kisspeptin cells in the ovine arcuate nucleus express prolactin receptor but not melatonin receptor.Journal of Neuroendocrinology Oct 2011Melatonin is secreted at night by the pineal gland and governs the reproductive system in seasonal breeders, such as sheep. The mechanism by which melatonin regulates...
Melatonin is secreted at night by the pineal gland and governs the reproductive system in seasonal breeders, such as sheep. The mechanism by which melatonin regulates reproduction is not known. The circannual rhythmicity of other factors, including prolactin, is also regulated by photoperiod via changes in melatonin secretion. In sheep, plasma prolactin levels are higher in the nonbreeding season than the breeding season. Kisspeptin, synthesised by neurones in the ovine arcuate nucleus (ARC) and preoptic area, is a key regulator of reproduction through stimulation of gonadotrophin-releasing hormone secretion and its expression in the ARC is reduced during the nonbreeding season. We hypothesised that kisspeptin expression is directly, or indirectly, regulated by melatonin and/or prolactin. We first examined the expression of melatonin receptor (MTNR1A) in kisspeptin (Kiss1 mRNA) neurones in the ARC of ovariectomised (OVX) sheep using double-label in situ hybridisation. MTNR1A mRNA was not expressed by kisspeptin neurones, whereas strong expression was detected in the pars tuberalis. We then examined the expression of the long-form prolactin receptor (PRLR-L) in ARC kisspeptin neurones. In OVX ewes, approximately 60% of kisspeptin neurones expressed PRLR-L mRNA at similar levels in the breeding and nonbreeding seasons. We then aimed to determine whether prolactin treatment during the breeding season regulates kisspeptin expression in the ARC. Continuous central infusion of prolactin (20 μg/h for 7 days) in oestradiol-treated OVX sheep did not alter Kiss1 mRNA expression or luteinising hormone secretion, although it induced substantial phosphorylated signal transducer and activator of transcription 5-immunoreactive nuclei staining in the mediobasal hypothalamus. We conclude that the seasonal change in kisspeptin neurones cannot be regulated directly by melatonin, although it may be a result of changes in prolactin levels. Despite this, kisspeptin expression was unchanged after exogenous prolactin treatment in breeding season ewes.
Topics: Animals; Arcuate Nucleus of Hypothalamus; Base Sequence; DNA Primers; Female; In Situ Hybridization; Kisspeptins; Ovariectomy; Prolactin; RNA, Messenger; Radioimmunoassay; Real-Time Polymerase Chain Reaction; Receptors, Melatonin; Receptors, Prolactin; Sheep
PubMed: 21793946
DOI: 10.1111/j.1365-2826.2011.02195.x -
The New England Journal of Medicine Mar 2014
Topics: Female; Germ-Line Mutation; Humans; Hyperprolactinemia; Male; Receptors, Prolactin
PubMed: 24597880
DOI: 10.1056/NEJMc1315848