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Banks CM, Trott JF, Hovey RC. The prolactin receptor: A cross-species comparison of gene structure, transcriptional regulation, tissue-specificity, and genetic variation. J Neuroendocrinol 2024; 36:e13385. [PMID: 38586906 DOI: 10.1111/jne.13385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/25/2024] [Accepted: 03/13/2024] [Indexed: 04/09/2024]
Abstract
The conserved and multifaceted functions of prolactin (PRL) are coordinated through varied distribution and expression of its cell-surface receptor (PRLR) across a range of tissues and physiological states. The resultant heterogeneous expression of PRLR mRNA and protein across different organs and cell types supports a wide range of PRL-regulated processes including reproduction, lactation, development, and homeostasis. Genetic variation within the PRLR gene also accounts for several phenotypes impacting agricultural production and human pathology. The goal of this review is to highlight the many elements that control differential expression of the PRLR across tissues, and the various phenotypes that exist across species due to variation in the PRLR gene.
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Affiliation(s)
- Carmen M Banks
- Department of Animal Science, University of California, Davis, Davis, California, USA
| | - Josephine F Trott
- Department of Animal Science, University of California, Davis, Davis, California, USA
| | - Russell C Hovey
- Department of Animal Science, University of California, Davis, Davis, California, USA
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2
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Page L, Younge N, Freemark M. Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant. Nutrients 2023; 15:4041. [PMID: 37764824 PMCID: PMC10537367 DOI: 10.3390/nu15184041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.
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Affiliation(s)
- Laura Page
- Division of Pediatric Endocrinology, Duke University Medical Center, Durham, NC 27710, USA;
| | - Noelle Younge
- Neonatology, Duke University Medical Center, Durham, NC 27710, USA;
| | - Michael Freemark
- Division of Pediatric Endocrinology, Duke University Medical Center, Durham, NC 27710, USA;
- The Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA
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3
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Simoni A, Huber HA, Georgia SK, Finley SD. Phosphatases are predicted to govern prolactin-mediated JAK–STAT signaling in pancreatic beta cells. Integr Biol (Camb) 2022; 14:37-48. [DOI: 10.1093/intbio/zyac004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Patients with diabetes are unable to produce a sufficient amount of insulin to properly regulate their blood glucose levels. One potential method of treating diabetes is to increase the number of insulin-secreting beta cells in the pancreas to enhance insulin secretion. It is known that during pregnancy, pancreatic beta cells proliferate in response to the pregnancy hormone, prolactin (PRL). Leveraging this proliferative response to PRL may be a strategy to restore endogenous insulin production for patients with diabetes. To investigate this potential treatment, we previously developed a computational model to represent the PRL-mediated JAK–STAT signaling pathway in pancreatic beta cells. Here, we applied the model to identify the importance of particular signaling proteins in shaping the response of a population of beta cells. We simulated a population of 10 000 heterogeneous cells with varying initial protein concentrations responding to PRL stimulation. We used partial least squares regression to analyze the significance and role of each of the varied protein concentrations in producing the response of the cell. Our regression models predict that the concentrations of the cytosolic and nuclear phosphatases strongly influence the response of the cell. The model also predicts that increasing PRL receptor strengthens negative feedback mediated by the inhibitor suppressor of cytokine signaling. These findings reveal biological targets that can potentially be used to modulate the proliferation of pancreatic beta cells to enhance insulin secretion and beta cell regeneration in the context of diabetes.
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Affiliation(s)
- Ariella Simoni
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Holly A Huber
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Senta K Georgia
- Departments of Pediatrics and Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
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4
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Salazar-Petres ER, Sferruzzi-Perri AN. Pregnancy-induced changes in β-cell function: what are the key players? J Physiol 2021; 600:1089-1117. [PMID: 33704799 DOI: 10.1113/jp281082] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Maternal metabolic adaptations during pregnancy ensure appropriate nutrient supply to the developing fetus. This is facilitated by reductions in maternal peripheral insulin sensitivity, which enables glucose to be available in the maternal circulation for transfer to the fetus for growth. To balance this process and avoid excessive hyperglycaemia and glucose intolerance in the mother during pregnancy, maternal pancreatic β-cells undergo remarkable changes in their function including increasing their proliferation and glucose-stimulated insulin secretion. In this review we examine how placental and maternal hormones work cooperatively to activate several signalling pathways, transcription factors and epigenetic regulators to drive adaptations in β-cell function during pregnancy. We also explore how adverse maternal environmental conditions, including malnutrition, obesity, circadian rhythm disruption and environmental pollutants, may impact the endocrine and molecular mechanisms controlling β-cell adaptations during pregnancy. The available data from human and experimental animal studies highlight the need to better understand how maternal β-cells integrate the various environmental, metabolic and endocrine cues and thereby determine appropriate β-cell adaptation during gestation. In doing so, these studies may identify targetable pathways that could be used to prevent not only the development of pregnancy complications like gestational diabetes that impact maternal and fetal wellbeing, but also more generally the pathogenesis of other metabolic conditions like type 2 diabetes.
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Affiliation(s)
- Esteban Roberto Salazar-Petres
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Amanda Nancy Sferruzzi-Perri
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
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5
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Mortlock RD, Georgia SK, Finley SD. Dynamic Regulation of JAK-STAT Signaling Through the Prolactin Receptor Predicted by Computational Modeling. Cell Mol Bioeng 2020; 14:15-30. [PMID: 33633812 PMCID: PMC7878662 DOI: 10.1007/s12195-020-00647-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 08/11/2020] [Indexed: 12/16/2022] Open
Abstract
Introduction The expansion of insulin-producing beta cells during pregnancy is critical to maintain glucose homeostasis in the face of increasing insulin resistance. Prolactin receptor (PRLR) signaling is one of the primary mediators of beta cell expansion during pregnancy, and loss of PRLR signaling results in reduced beta cell mass and gestational diabetes. Harnessing the proliferative potential of prolactin signaling to expand beta cell mass outside of the context of pregnancy requires quantitative understanding of the signaling at the molecular level. Methods A mechanistic computational model was constructed to describe prolactin-mediated JAK-STAT signaling in pancreatic beta cells. The effect of different regulatory modules was explored through ensemble modeling. A Bayesian approach for likelihood estimation was used to fit the model to experimental data from the literature. Results Including receptor upregulation, with either inhibition by SOCS proteins, receptor internalization, or both, allowed the model to match experimental results for INS-1 cells treated with prolactin. The model predicts that faster dimerization and nuclear import rates of STAT5B compared to STAT5A can explain the higher STAT5B nuclear translocation. The model was used to predict the dose response of STAT5B translocation in rat primary beta cells treated with prolactin and reveal possible strategies to modulate STAT5 signaling. Conclusions JAK-STAT signaling must be tightly controlled to obtain the biphasic response in STAT5 activation seen experimentally. Receptor up-regulation, combined with SOCS inhibition, receptor internalization, or both is required to match experimental data. Modulating reactions upstream in the signaling can enhance STAT5 activation to increase beta cell survival. Electronic supplementary material The online version of this article (10.1007/s12195-020-00647-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ryland D Mortlock
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA USA
| | - Senta K Georgia
- Departments of Pediatrics and Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Stacey D Finley
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA USA.,Department of Biomedical Engineering, University of Southern California, Los Angeles, CA USA.,Department of Biological Sciences, University of Southern California, Los Angeles, CA USA
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6
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Møldrup A, Lindberg MN, Galsgaard ED, Henriksen U, Dalgaard LT, Nielsen JH. Regulation of integrin α6A by lactogenic hormones in rat pancreatic β-cells: Implications for the physiological adaptation to pregnancy. Acta Physiol (Oxf) 2020; 229:e13454. [PMID: 32056357 DOI: 10.1111/apha.13454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/30/2020] [Accepted: 02/10/2020] [Indexed: 12/12/2022]
Abstract
AIM During pregnancy, the maternal β-cell mass is increased in order to adapt to the physiological changes in insulin demand. Lactogenic hormones stimulate rodent β-cell attachment and proliferation in vitro. The aim of this study was to identify adhesion molecules involved in expansion of the β-cell mass during pregnancy in the rat. METHODS Quantitative RT-PCR was used to evaluate the expression of several integrins and laminins in isolated neonatal rat islets in response to growth hormone (GH) and prolactin (PRL) treatment. Double-immunofluorescence staining of rat pancreas was used to localize the expression of integrin α6β1. β-cell proliferation was evaluated by incorporation of bromodeoxyuridine (BrdU). The role of STAT5 phosphorylation was tested by addition of STAT5 mutants. RESULTS We found that the mRNA level of integrin-α6A, was upregulated 2.5-fold by PRL or GH. During pregnancy, a biphasic 3.4-4.5-fold increase of integrin-α6A and B mRNA levels was detected. A disintegrin peptide (DP) reduced the hormone-stimulated mitotic activity in neonatal rat β-cells from 2.9 ± 0.4-fold to 1.3 ± 0.3-fold. The hormone-induced expression of α6β1 integrin was shown to be mediated via STAT5 as a dominant negative (DN) mutant prevented and a constitutive active (CA) mutant augmented the hGH-stimulated expression. The DP was found to inhibit hGH-induced transactivation of the PRL receptor promoter 1A and reduce the hGH-induced phosphorylation of STAT5. CONCLUSION These results show that integrin-α6 in β-cells is upregulated by lactogenic hormones and is required but not sufficient for the expansion of the β-cell mass in pregnancy in the rat, which may have implications for the understanding and treatment of gestational diabetes mellitus.
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Affiliation(s)
| | | | | | - Ulrik Henriksen
- Department of Biomedical Sciences University of Copenhagen Copenhagen Denmark
| | - Louise T. Dalgaard
- Department of Science and Environment Roskilde University Roskilde Denmark
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7
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Banerjee RR. Piecing together the puzzle of pancreatic islet adaptation in pregnancy. Ann N Y Acad Sci 2019; 1411:120-139. [PMID: 29377199 DOI: 10.1111/nyas.13552] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/18/2017] [Accepted: 10/24/2017] [Indexed: 12/20/2022]
Abstract
Pregnancy places acute demands on maternal physiology, including profound changes in glucose homeostasis. Gestation is characterized by an increase in insulin resistance, counterbalanced by an adaptive increase in pancreatic β cell production of insulin. Failure of normal adaptive responses of the islet to increased maternal and fetal demands manifests as gestational diabetes mellitus (GDM). The gestational changes and rapid reversal of islet adaptations following parturition are at least partly driven by an anticipatory program rather than post-factum compensatory adaptations. Here, I provide a comprehensive review of the cellular and molecular mechanisms underlying normal islet adaptation during pregnancy and how dysregulation may lead to GDM. Emerging areas of interest and understudied areas worthy of closer examination in the future are highlighted.
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Affiliation(s)
- Ronadip R Banerjee
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, and the Comprehensive Diabetes Center, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
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Pepin ME, Bickerton HH, Bethea M, Hunter CS, Wende AR, Banerjee RR. Prolactin Receptor Signaling Regulates a Pregnancy-Specific Transcriptional Program in Mouse Islets. Endocrinology 2019; 160:1150-1163. [PMID: 31004482 PMCID: PMC6475113 DOI: 10.1210/en.2018-00991] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/25/2019] [Indexed: 12/14/2022]
Abstract
Pancreatic β-cells undergo profound hyperplasia during pregnancy to maintain maternal euglycemia. Failure to reprogram β-cells into a more replicative state has been found to underlie susceptibility to gestational diabetes mellitus (GDM). We recently identified a requirement for prolactin receptor (PRLR) signaling in the metabolic adaptations to pregnancy, where β-cell-specific PRLR knockout (βPRLRKO) mice exhibit a metabolic phenotype consistent with GDM. However, the underlying transcriptional program that is responsible for the PRLR-dependent metabolic adaptations during gestation remains incompletely understood. To identify PRLR signaling gene regulatory networks and target genes within β-cells during pregnancy, we performed a transcriptomic analysis of pancreatic islets isolated from either βPRLRKO mice or littermate controls in late gestation. Gene set enrichment analysis identified forkhead box protein M1 and polycomb repressor complex 2 subunits, Suz12 and enhancer of zeste homolog 2 (Ezh2), as novel candidate regulators of PRLR-dependent β-cell adaptation. Gene ontology term pathway enrichment revealed both established and novel PRLR signaling target genes that together promote a state of increased cellular metabolism and/or proliferation. In contrast to the requirement for β-cell PRLR signaling in maintaining euglycemia during pregnancy, PRLR target genes were not induced following high-fat diet feeding. Collectively, the current study expands our understanding of which transcriptional regulators and networks mediate gene expression required for islet adaptation during pregnancy. The current work also supports the presence of pregnancy-specific adaptive mechanisms distinct from those activated by nutritional stress.
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Affiliation(s)
- Mark E Pepin
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Pathology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Hayden H Bickerton
- Division of Endocrinology, Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
- University of Alabama at Birmingham Comprehensive Diabetes Center, Birmingham, Alabama
| | - Maigen Bethea
- Division of Endocrinology, Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
- University of Alabama at Birmingham Comprehensive Diabetes Center, Birmingham, Alabama
| | - Chad S Hunter
- Division of Endocrinology, Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
- University of Alabama at Birmingham Comprehensive Diabetes Center, Birmingham, Alabama
| | - Adam R Wende
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Pathology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
- University of Alabama at Birmingham Comprehensive Diabetes Center, Birmingham, Alabama
| | - Ronadip R Banerjee
- Division of Endocrinology, Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
- University of Alabama at Birmingham Comprehensive Diabetes Center, Birmingham, Alabama
- Correspondence: Ronadip R. Banerjee, MD, PhD, Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Alabama School of Medicine, Boshell Diabetes Building 730, 1808 7th Avenue South, Birmingham, Alabama 35294. E-mail:
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9
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Sisino G, Zhou AX, Dahr N, Sabirsh A, Soundarapandian MM, Perera R, Larsson-Lekholm E, Magnone MC, Althage M, Tyrberg B. Long noncoding RNAs are dynamically regulated during β-cell mass expansion in mouse pregnancy and control β-cell proliferation in vitro. PLoS One 2017; 12:e0182371. [PMID: 28796801 PMCID: PMC5552087 DOI: 10.1371/journal.pone.0182371] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022] Open
Abstract
Pregnancy is associated with increased β-cell proliferation driven by prolactin. Long noncoding RNAs (lncRNA) are the most abundant RNA species in the mammalian genome, yet, their functional importance is mainly elusive. Aims/hypothesis: This study tests the hypothesis that lncRNAs regulate β-cell proliferation in response to prolactin in the context of β-cell mass compensation in pregnancy. Methods: The expression profile of lncRNAs in mouse islets at day 14.5 of pregnancy was explored by a bioinformatics approach, further confirmed by quantitative PCR at different days of pregnancy, and islet specificity was evaluated by comparing expression in islets versus other tissues. In order to establish the role of the candidate lncRNAs we studied cell proliferation in mouse islets and the MIN6 β-cell line by EdU incorporation and cell count. Results: We found that a group of lncRNAs is differentially regulated in mouse islets at 14.5 days of pregnancy. At different stages of pregnancy, these lncRNAs are dynamically expressed, and expression is prolactin dependent in mouse islets and MIN6 cells. One of those lncRNAs, Gm16308 (Lnc03), is dynamically regulated during pregnancy, prolactin-dependent and islet-enriched. Silencing Lnc03 in primary β-cells and MIN6 cells inhibits, whereas over-expression stimulates, proliferation even in the absence of prolactin, demonstrating that Lnc03 regulates β-cell growth. Conclusions/interpretation: During pregnancy mouse islet proliferation is correlated with dynamic changes of lncRNA expression. In particular, Lnc03 regulates mouse β-cell proliferation and may be a crucial component of β-cell proliferation in β-cell mass adaptation in both health and disease.
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Affiliation(s)
- Giorgia Sisino
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Alex-Xianghua Zhou
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Niklas Dahr
- Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Alan Sabirsh
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | | | - Ranjan Perera
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, United States of America
| | | | - Maria Chiara Magnone
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Magnus Althage
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Björn Tyrberg
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
- * E-mail:
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Luque GM, Lopez-Vicchi F, Ornstein AM, Brie B, De Winne C, Fiore E, Perez-Millan MI, Mazzolini G, Rubinstein M, Becu-Villalobos D. Chronic hyperprolactinemia evoked by disruption of lactotrope dopamine D2 receptors impacts on liver and adipocyte genes related to glucose and insulin balance. Am J Physiol Endocrinol Metab 2016; 311:E974-E988. [PMID: 27802964 DOI: 10.1152/ajpendo.00200.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 10/21/2016] [Accepted: 10/23/2016] [Indexed: 12/21/2022]
Abstract
We studied the impact of high prolactin titers on liver and adipocyte gene expression related to glucose and insulin homeostasis in correlation with obesity onset. To that end we used mutant female mice that selectively lack dopamine type 2 receptors (D2Rs) from pituitary lactotropes (lacDrd2KO), which have chronic high prolactin levels associated with increased body weight, marked increments in fat depots, adipocyte size, and serum lipids, and a metabolic phenotype that intensifies with age. LacDrd2KO mice of two developmental ages, 5 and 10 mo, were used. In the first time point, obesity and increased body weight are marginal, although mice are hyperprolactinemic, whereas at 10 mo there is marked adiposity with a 136% increase in gonadal fat and a 36% increase in liver weight due to lipid accumulation. LacDrd2KO mice had glucose intolerance, hyperinsulinemia, and impaired insulin response to glucose already in the early stages of obesity, but changes in liver and adipose tissue transcription factors were time and tissue dependent. In chronic hyperprolactinemic mice liver Prlr were upregulated, there was liver steatosis, altered expression of the lipogenic transcription factor Chrebp, and blunted response of Srebp-1c to refeeding at 5 mo of age, whereas no effect was observed in the glycogenesis pathway. On the other hand, in adipose tissue a marked decrease in lipogenic transcription factor expression was observed when morbid obesity was already settled. These adaptive changes underscore the role of prolactin signaling in different tissues to promote energy storage.
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Affiliation(s)
- Guillermina María Luque
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Felicitas Lopez-Vicchi
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Ana María Ornstein
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Belén Brie
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Catalina De Winne
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Esteban Fiore
- Laboratorio de Terapia Génica, Instituto de Investigaciones en Medicina Traslacional (IIMT-CONICET), Universidad Austral, Buenos Aires, Argentina; and
| | - Maria Inés Perez-Millan
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Guillermo Mazzolini
- Laboratorio de Terapia Génica, Instituto de Investigaciones en Medicina Traslacional (IIMT-CONICET), Universidad Austral, Buenos Aires, Argentina; and
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, CONICET, and Departamento de Fisiología, y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Damasia Becu-Villalobos
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina;
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Zhao D, Ma G, Zhang X, He Y, Li M, Han X, Fu L, Dong XY, Nagy T, Zhao Q, Fu L, Dong JT. Zinc Finger Homeodomain Factor Zfhx3 Is Essential for Mammary Lactogenic Differentiation by Maintaining Prolactin Signaling Activity. J Biol Chem 2016; 291:12809-12820. [PMID: 27129249 DOI: 10.1074/jbc.m116.719377] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 12/13/2022] Open
Abstract
The zinc finger homeobox 3 (ZFHX3, also named ATBF1 for AT motif binding factor 1) is a transcription factor that suppresses prostatic carcinogenesis and induces neuronal differentiation. It also interacts with estrogen receptor α to inhibit cell proliferation and regulate pubertal mammary gland development in mice. In the present study, we examined whether and how Zfhx3 regulates lactogenic differentiation in mouse mammary glands. At different stages of mammary gland development, Zfhx3 protein was expressed at varying levels, with the highest level at lactation. In the HC11 mouse mammary epithelial cell line, an in vitro model of lactogenesis, knockdown of Zfhx3 attenuated prolactin-induced β-casein expression and morphological changes, indicators of lactogenic differentiation. In mouse mammary tissue, knock-out of Zfhx3 interrupted lactogenesis, resulting in underdeveloped glands with much smaller and fewer alveoli, reduced β-casein expression, accumulation of large cytoplasmic lipid droplets in luminal cells after parturition, and failure in lactation. Mechanistically, Zfhx3 maintained the expression of Prlr (prolactin receptor) and Prlr-Jak2-Stat5 signaling activity, whereas knockdown and knock-out of Zfhx3 in HC11 cells and mammary tissues, respectively, decreased Prlr expression, Stat5 phosphorylation, and the expression of Prlr-Jak2-Stat5 target genes. These findings indicate that Zfhx3 plays an essential role in proper lactogenic development in mammary glands, at least in part by maintaining Prlr expression and Prlr-Jak2-Stat5 signaling activity.
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Affiliation(s)
- Dan Zhao
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Gui Ma
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiaolin Zhang
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yuan He
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Mei Li
- the Ningbo Institute of Medical Sciences, Ningbo 315020, China
| | - Xueying Han
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Liya Fu
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xue-Yuan Dong
- the Department of Hematology and Medical Oncology, School of Medicine, Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - Tamas Nagy
- the Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, and
| | - Qiang Zhao
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Li Fu
- the Cancer Hospital of Tianjin Medical University, Tianjin 300060, China
| | - Jin-Tang Dong
- From the Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China,; the Department of Hematology and Medical Oncology, School of Medicine, Winship Cancer Institute, Emory University, Atlanta, Georgia 30322,.
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Ginis Z, Ucar F, Erdogan S, Ozturk G, Akyol S, Erden G, Arslan MS, Delibasi T. Serum vaspin and adiponectin levels in patients with prolactinoma. Scand J Clin Lab Invest 2015; 76:17-24. [PMID: 26415032 DOI: 10.3109/00365513.2015.1085080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Studies investigating serum vaspin and adiponectin levels in patients with prolactinoma are inconclusive. The aim of this study was to evaluate serum vaspin and adiponectin levels in patients with prolactinoma and healthy controls. METHODS A total of 42 prolactinoma patients (Group 1, 21 patients; Group 2, 21 patients) and 30 healthy controls were enrolled in the study. Group 1 consisted of newly diagnosed patients who were never treated or had not received a dopamine agonist (DA) within 6 months prior to screening. Group 2 consisted of prolactinoma patients who were on DA treatment for at least 6 months at the time of screening. The control group (group 3) consisted of healthy controls. RESULTS Patients with prolactinoma had higher homeostasis model assessment of insulin resistance and lower quantitative insulin sensitivity check index values in comparison to healthy controls (p < 0.001 for both). Serum levels of adiponectin and vaspin were also significantly lower in prolactinoma patients when compared to the control group (p < 0.01 and p < 0.001, respectively). Following adjustment for confounding factors, the respective odds ratios for prolactinoma in patients in the lower subgroup compared with those in the higher subgroup for adiponectin and vaspin were 2.733 (0.621-12.035; p > 0.05) and 5.041 (1.191-21.339; p < 0.05). CONCLUSION This is the first study to demonstrate the presence of low vaspin levels in patients with prolactinomas. Further studies are needed to help establish the roles of vaspin and adiponectin in prolactinoma patients.
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Affiliation(s)
- Zeynep Ginis
- a Department of Biochemistry , Faculty of Medicine, Gazi University , Ankara
| | - Fatma Ucar
- b Department of Biochemistry , Diskapi Yildirim Beyazit Education and Research Hospital , Ankara
| | - Serpil Erdogan
- c Department of Biochemistry , Ataturk Training and Research Hospital , Ankara
| | - Gulfer Ozturk
- b Department of Biochemistry , Diskapi Yildirim Beyazit Education and Research Hospital , Ankara
| | - Sumeyye Akyol
- d Medical Laboratory Techniques , Vocational School of Medical Sciences Turgut Ozal University , Ankara
| | - Gonul Erden
- b Department of Biochemistry , Diskapi Yildirim Beyazit Education and Research Hospital , Ankara.,e Department of Biochemistry , Kastamonu Faculty of Medicine, Hacettepe University , Ankara
| | - Muyesser Sayki Arslan
- f Department of Endocrinology and Metabolism , Diskapi Yildirim Beyazit Education and Research Hospital , Ankara
| | - Tuncay Delibasi
- f Department of Endocrinology and Metabolism , Diskapi Yildirim Beyazit Education and Research Hospital , Ankara.,g Department of Endocrinology and Metabolism , Kastamonu Faculty of Medicine, Hacettepe University , Ankara , Turkey
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SALVATIERRA CRISTIANAS, REIS SÍLVIAR, PESSOA ANAF, SOUZA LETÍCIAMDE, STOPPIGLIA LUIZF, VELOSO ROBERTOV, REIS MARISEA, CARNEIRO EVERARDOM, BOSCHERO ANTONIOC, COLODEL EDSONM, ARANTES VANESSAC, LATORRACA MÁRCIAQ. Short-term low-protein diet during pregnancy alters islet area and protein content of phosphatidylinositol 3-kinase pathway in rats. ACTA ACUST UNITED AC 2015; 87:1007-18. [DOI: 10.1590/0001-3765201520140251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 12/15/2014] [Indexed: 12/31/2022]
Abstract
The phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways mediate β cell growth, proliferation, survival and death. We investigated whether protein restriction during pregnancy alters islet morphometry or the expression and phosphorylation of several proteins involved in the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways. As controls, adult pregnant and non-pregnant rats were fed a normal-protein diet (17%). Pregnant and non-pregnant rats in the experimental groups were fed a low-protein diet (6%) for 15 days. Low protein diet during pregnancy increased serum prolactin level, reduced serum corticosterone concentration and the expression of both protein kinase B/AKT1 (AKT1) and p70 ribosomal protein S6 kinase (p70S6K), as well as the islets area, but did not alter the insulin content of pancreatic islets. Pregnancy increased the expression of the Src homology/collagen (SHC) protein and the extracellular signal-regulated kinases 1/2 (ERK1/2) independent of diet. ERK1/2 phosphorylation (pERK1/2) was similar in islets from pregnant and non-pregnant rats fed a low-protein diet, and was higher in islets from pregnant rats than in islets from non-pregnant rats fed a normal-protein diet. Thus, a short-term, low-protein diet during pregnancy was sufficient to reduce the levels of proteins in the phosphatidylinositol 3-kinase pathway and affect islet morphometry.
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Jiao Y, Rieck S, Le Lay J, Kaestner KH. CISH has no non-redundant functions in glucose homeostasis or beta cell proliferation during pregnancy in mice. Diabetologia 2013; 56:2435-45. [PMID: 23949579 PMCID: PMC3816496 DOI: 10.1007/s00125-013-3014-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 07/16/2013] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Increased beta cell proliferation during pregnancy is mediated by the Janus kinase 2/signal transducer and activator of transcription 5 (JAK2/STAT5) signalling pathway in response to increased lactogen levels. Activation of the pathway leads to transcriptional upregulation of Cish (encoding cytokine-inducible SH2 domain-containing protein), a member of the suppressor of cytokine signalling (SOCS) family of genes, forming a negative-feedback loop. Here, we examined whether conditional gene ablation of Cish in the pancreas improves beta cell proliferation and beta cell function during pregnancy in mice. METHODS We derived mice with a novel, conditional loxP allele for Cish. Pancreas-specific ablation of Cish was achieved by crossing Cish (loxP/loxP) mice with Pdx1-Cre (Early) mice. Beta cell proliferation was quantified by BrdU labelling. Glucose homeostasis was examined with glucose tolerance tests and determination of plasma insulin levels. The expression of other Socs genes and target genes of p-STAT5 related to beta cell function and beta cell proliferation was determined by quantitative PCR. RESULTS There was no difference in beta cell proliferation or glucose homeostasis between the Cish mutant group and the control group. The p-STAT5 protein level was the same in Cish mutant and control mice. Socs2 gene expression was higher in Cish mutant than control mice at pregnancy day 9.5. The expression of other Socs genes was the same between control and mutant mice. CONCLUSIONS/INTERPRETATION Our results show that CISH has no non-redundant functions in beta cell proliferation or glucose homeostasis during pregnancy in mice. Socs2 might compensate for the loss of Cish during pregnancy.
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Affiliation(s)
- Yang Jiao
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sebastian Rieck
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - John Le Lay
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Klaus H. Kaestner
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- 12-126 Smilow Center for Translational Research, 3400 Civic Center Blvd Bldg 421, Philadelphia, PA 19104-5156
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Beta-cell ARNT is required for normal glucose tolerance in murine pregnancy. PLoS One 2013; 8:e77419. [PMID: 24204824 PMCID: PMC3812008 DOI: 10.1371/journal.pone.0077419] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/10/2013] [Indexed: 11/19/2022] Open
Abstract
AIMS Insulin secretion increases in normal pregnancy to meet increasing demands. Inability to increase beta-cell function results in gestational diabetes mellitus (GDM). We have previously shown that the expression of the transcription factor ARNT (Aryl-hydrocarbon Receptor Nuclear Translocator) is reduced in the islets of humans with type 2 diabetes. Mice with a beta-cell specific deletion of ARNT (β-ARNT mice) have impaired glucose tolerance secondary to defective insulin secretion. We hypothesised that ARNT is required to increase beta-cell function during pregnancy, and that β-ARNT mice would be unable to compensate for the beta-cell stress of pregnancy. The aims of this study were to investigate the mechanisms of ARNT regulation of beta-cell function and glucose tolerance in pregnancy. METHODS β-ARNT females were mated with floxed control (FC) males and FC females with β-ARNT males. RESULTS During pregnancy, β-ARNT mice had a marked deterioration in glucose tolerance secondary to defective insulin secretion. There was impaired beta-cell proliferation in late pregnancy, associated with decreased protein and mRNA levels of the islet cell-cycle regulator cyclinD2. There was also reduced expression of Irs2 and G6PI. In contrast, in control mice, pregnancy was associated with a 2.1-fold increase in ARNT protein and a 1.6-fold increase in cyclinD2 protein, and with increased beta-cell proliferation. CONCLUSIONS Islet ARNT increases in normal murine pregnancy and beta-cell ARNT is required for cyclinD2 induction and increased beta-cell proliferation in pregnancy.
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Lellis-Santos C, Sakamoto LH, Bromati CR, Nogueira TCA, Leite AR, Yamanaka TS, Kinote A, Anhê GF, Bordin S. The regulation of Rasd1 expression by glucocorticoids and prolactin controls peripartum maternal insulin secretion. Endocrinology 2012; 153:3668-78. [PMID: 22700767 DOI: 10.1210/en.2012-1135] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The transition from gestation to lactation is characterized by a robust adaptation of maternal pancreatic β-cells. Consistent with the loss of β-cell mass, glucose-induced insulin secretion is down-regulated in the islets of early lactating dams. Extensive experimental evidence has demonstrated that the surge of prolactin is responsible for the morphofunctional remodeling of the maternal endocrine pancreas during pregnancy, but the precise molecular mechanisms by which this phenotype is rapidly reversed after delivery are not completely understood. This study investigated whether glucocorticoid-regulated expression of Rasd1/Dexras, a small inhibitory G protein, is involved in this physiological plasticity. Immunofluorescent staining demonstrated that Rasd1 is localized within pancreatic β-cells. Rasd1 expression in insulin-secreting cells was increased by dexamethasone and decreased by prolactin. In vivo data confirmed that Rasd1 expression is decreased in islets from pregnant rats and increased in islets from lactating mothers. Knockdown of Rasd1 abolished the inhibitory effects of dexamethasone on insulin secretion and the protein kinase A, protein kinase C, and ERK1/2 pathways. Chromatin immunoprecipitation experiments revealed that glucocorticoid receptor (GR) and signal transducer and activator of transcription 5b (STAT5b) cooperatively mediate glucocorticoid-induced Rasd1 expression in islets. Prolactin inhibited the stimulatory effect of GR/STAT5b complex on Rasd1 transcription. Overall, our data indicate that the stimulation of Rasd1 expression by glucocorticoid at the end of pregnancy reverses the increased insulin secretion that occurs during pregnancy. Prolactin negatively regulates this pathway by inhibiting GR/STAT5b transcriptional activity on the Rasd1 gene.
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Affiliation(s)
- Camilo Lellis-Santos
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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Edelmann MN, Auger AP. Epigenetic impact of simulated maternal grooming on estrogen receptor alpha within the developing amygdala. Brain Behav Immun 2011; 25:1299-304. [PMID: 21352906 PMCID: PMC3399737 DOI: 10.1016/j.bbi.2011.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/15/2011] [Accepted: 02/15/2011] [Indexed: 01/06/2023] Open
Abstract
Variations in maternal care alter the developmental programming of some genes by creating lasting differences in DNA methylation patterns, such as the estrogen receptor alpha (ERα) promoter region. Interestingly, mother rats preferentially lick and groom their male offspring more than females; therefore, we questioned whether the somatosensory stimuli associated with maternal grooming influences potential sex differences in DNA methylation patterns within the developing amygdala, an area important for socioemotional processing. We report a sex difference in the DNA methylation pattern of specific CpG sites of the ERα promoter region within the developing amygdala. Specifically, males have higher levels of ERα promoter methylation contrasted to females. Increasing the levels of maternal stimuli in females masculinized ERα promoter methylation patterns to male-like levels. As expected, higher levels of ERα promoter methylation were associated with lower ERα mRNA levels. These data provide further evidence that the early neonatal environment, particularly maternal care, contributes to sex differences and early programming of the neonatal brain via an epigenetic mechanism.
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Affiliation(s)
| | - Anthony P. Auger
- Corresponding author. Address: Department of Psychology, 1202 W Johnson Street, Madison, WI 53706, USA. (A.P. Auger)
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18
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Abstract
OBJECTIVES Recent studies demonstrated that prolactin (PRL) has beneficial effects on beta cells for islet transplantation. We examined the effect of human recombinant PRL (rhPRL) supplementation to the culture media to determine its potential use in the context of clinical islet transplantation. MATERIALS AND METHODS Each human islet isolated from 14 deceased multiorgan donors was cultured in Miami modified media-1 supplemented with or without rhPRL (500 microg/L) for 48 hr. beta-Cell survival and proliferation (BrdU and Ki-67) were determined by laser scanning cytometry. The cytoprotective effects of rhPRL against noxious stimuli were assessed by flow cytometry (tetramethylrhodamine ethyl ester). Cytokine/chemokine and tissue factor productions were measured in vitro, and islet potency was assessed in vivo in diabetic immunodeficient mice. RESULTS beta-Cell survival during culture was 37% higher in the rhPRL group than in control (P=0.029). rhPRL protected beta cells in vitro from cytokines, Nitric oxide donor, and H2O2. The exposure to rhPRL did not affect human beta-cell proliferation with our protocol. rhPRL treatment did not alter cytokine/chemokine and tissue factor production in vitro or affected human islet functionality in vivo: recipient mice achieved normoglycemia with a comparable tempo, whereas loss of graft function was observed in two of the seven mice in the control group and in none of the rhPRL group (p=n.s.). CONCLUSION rhPRL supplementation to islet culture media improved human beta-cell-specific survival without altering islet quality. Addition of rhPRL to cultured islets may grant a more viable beta-cell mass in culture. The development of beta-cell cytoprotective strategies will be of assistance in improving islet transplantation outcomes.
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Anderson ST, Isa NNM, Barclay JL, Waters MJ, Curlewis JD. Maximal expression of suppressors of cytokine signaling in the rat ovary occurs in late pregnancy. Reproduction 2009; 138:537-44. [DOI: 10.1530/rep-08-0425] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Maintenance of the rodent corpus luteum (CL) during pregnancy requires prolactin receptor (PRLR) signal transduction via STAT5. At the end of pregnancy, prostaglandin F2α (PGF2α) induces luteal regression through many mechanisms, including downregulation of PRLR signaling. We have previously shown that a PGF2α analog upregulates suppressors of cytokine signaling (SOCS) proteins in the CL of day 19 pregnant rats leading to reduced STAT5 signaling. Here, we examined endogenous SOCS expression and STAT5 signaling in the rat ovary during normal pregnancy and luteolysis. The mRNA expression of Socs1, Socs2, and Socs3 and related cytokine-inducible SH2-containing protein (Cish) was low in early pregnancy (day 7), but significantly increased at mid-pregnancy (days 10 and 13) associated with increased endogenous tyrosine phosphorylation (TyrP) of STAT5. In support of the notion that these changes are due to increasing placental lactogen levels at this time, we found that treatment with exogenous PRL on day 7 increased TyrP of STAT5 and induced SOCS mRNA expression, except Socs3. After mid-pregnancy, further significant increases in Socs3 and Cish mRNA expression were observed. Such changes in mRNA expression correlated with protein levels, with protein levels of both SOCS3 and CISH being maximal in late pregnancy (days 19–21). In addition, a significant reduction in TyrP of STAT5 was first observed on day 20, with a further substantial decrease on day 21. Therefore, these results are consistent with the hypothesis that increased SOCS expression in the rat ovary during late pregnancy reduces STAT5 signaling, which may be important in PGF2α-induced luteolysis.
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Abstract
Signal transducer and activator of transcription (STAT)5A and -5B are latent transcription factors activated by cytokines and hormones of the cytokine family. In pancreatic insulin-secreting β-cells, STAT5A and -5B are activated primarily by prolactin and growth hormone stimulation and are important mediators of the potent stimulation of proliferation and insulin production caused by these hormones. STAT5A and -5B are both expressed in β-cells and control the expression of a number of mRNAs implicated in cell replication control, insulin biosynthesis and secretion. In addition to STAT5A and -5B being transcriptional activators, they may also repress gene transcription. By these means, STAT5 proteins increase the levels of anti-apoptotic transcripts in β-cells and repress expression of pro-apoptotic genes. This review focuses on the anti-apoptotic role of STAT5 signaling, providing a mechanism for β-cell resistance to pro-apoptotic cytokines, Type 1 diabetes mellitus and obesity-associated β-cell stress. It is clear from studies of STAT5 signaling in pancreatic β-cells that STAT5 is important for postnatal β-cell compensatory growth (as in pregnancy or obesity) and in the defense against β-cell stress factors.
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Affiliation(s)
- Louise T Dalgaard
- a Roskilde University, Department of Science, Universitetsvej 1, DK-4000 Roskilde, Denmark.
| | - Nils Billestrup
- b Steno Diabetes Center, Niels Steensens Vej 2, DK-2820 Gentofte, Denmark.
| | - Jens H Nielsen
- c University of Copenhagen, Department of Biomedical Research, Panum Institute, Bldg 6.5, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark.
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Anderson GM, Kieser DC, Steyn FJ, Grattan DR. Hypothalamic prolactin receptor messenger ribonucleic acid levels, prolactin signaling, and hyperprolactinemic inhibition of pulsatile luteinizing hormone secretion are dependent on estradiol. Endocrinology 2008; 149:1562-70. [PMID: 18162529 DOI: 10.1210/en.2007-0867] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hyperprolactinemia can reduce fertility and libido. Although central prolactin actions are thought to contribute to this, the mechanisms are poorly understood. We first tested whether chronic hyperprolactinemia inhibited two neuroendocrine parameters necessary for female fertility: pulsatile LH secretion and the estrogen-induced LH surge. Chronic hyperprolactinemia induced by the dopamine antagonist sulpiride caused a 40% reduction LH pulse frequency in ovariectomized rats, but only in the presence of chronic low levels of estradiol. Sulpiride did not affect the magnitude of a steroid-induced LH surge or the percentage of GnRH neurons activated during the surge. Estradiol is known to influence expression of the long form of prolactin receptors (PRL-R) and components of prolactin's signaling pathway. To test the hypothesis that estrogen increases PRL-R expression and sensitivity to prolactin, we next demonstrated that estradiol greatly augments prolactin-induced STAT5 activation. Lastly, we measured PRL-R and suppressor of cytokine signaling (SOCS-1 and -3 and CIS, which reflect the level of prolactin signaling) mRNAs in response to sulpiride and estradiol. Sulpiride induced only SOCS-1 in the medial preoptic area, where GnRH neurons are regulated, but in the arcuate nucleus and choroid plexus, PRL-R, SOCS-3, and CIS mRNA levels were also induced. Estradiol enhanced these effects on SOCS-3 and CIS. Interestingly, estradiol also induced PRL-R, SOCS-3, and CIS mRNA levels independently. These data show that GnRH pulse frequency is inhibited by chronic hyperprolactinemia in a steroid-dependent manner. They also provide evidence for estradiol-dependent and brain region-specific regulation of PRL-R expression and signaling responses by prolactin.
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Affiliation(s)
- Greg M Anderson
- Centre for Neuroendocrinology and Department of Anatomy and Structural Biology, University of Otago School of Medical Sciences, Dunedin, New Zealand.
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ICA512 signaling enhances pancreatic beta-cell proliferation by regulating cyclins D through STATs. Proc Natl Acad Sci U S A 2008; 105:674-9. [PMID: 18178618 DOI: 10.1073/pnas.0710931105] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Changes in metabolic demands dynamically regulate the total mass of adult pancreatic beta-cells to adjust insulin secretion and preserve glucose homeostasis. Glucose itself is a major regulator of beta-cell proliferation by inducing insulin secretion and activating beta-cell insulin receptors. Here, we show that islet cell autoantigen 512 (ICA512)/IA-2, an intrinsic tyrosine phosphatase-like protein of the secretory granules, activates a complementary pathway for beta-cell proliferation. On granule exocytosis, the ICA512 cytoplasmic domain is cleaved and the resulting cytosolic fragment (ICA512-CCF) moves into the nucleus where it enhances the levels of phosphorylated STAT5 and STAT3, thereby inducing insulin gene transcription and granule biogenesis. We now show that knockdown of ICA512 decreases cyclin D1 levels and proliferation of insulinoma INS-1 cells, whereas beta-cell regeneration is reduced in partially pancreatectomized ICA512-/- mice. Conversely, overexpression of ICA512-CCF increases both cyclin D1 and D2 levels and INS-1 cell proliferation. Up-regulation of cyclin D1 and D2 by ICA512-CCF is affected by knockdown of STAT3 and STAT5, respectively, whereas it does not require insulin signaling. These results identify ICA512 as a regulator of cyclins D and beta-cell proliferation through STATs and may have implication for diabetes therapy.
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Ahmed TA, Buzzelli MD, Lang CH, Capen JB, Shumate ML, Navaratnarajah M, Nagarajan M, Cooney RN. Interleukin-6 inhibits growth hormone-mediated gene expression in hepatocytes. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1793-803. [PMID: 17395896 DOI: 10.1152/ajpgi.00547.2006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
During systemic inflammation, the liver becomes unresponsive to growth hormone (GH), resulting in decreased plasma insulin-like growth factor-I (IGF-I) with concomitant reductions in lean body mass. Transgenic mice that overexpress IL-6 also demonstrate impaired growth and decreased IGF-I. To determine whether IL-6 directly inhibits GH-inducible gene expression, CWSV-1 hepatocytes were incubated with IL-6 (10 ng/ml), then stimulated with recombinant human GH (500 ng/ml, 18 h). The increase in IGF-I and serine protease inhibitor 2.1 (Spi 2.1) mRNA in GH-treated cells was inhibited by treatment with IL-6 for 24 h. To investigate potential mechanisms, we examined the effects of IL-6 on GH receptor (GHR) expression and GH signaling via the JAK/signal transducer and activator of transcription (STAT) and MAP kinase pathways. Incubation of cells with IL-6 (10 ng/ml, 24 h) had no effect on GHR abundance or signaling proteins JAK2, STAT5b, and ERK1/2. Although GH transiently increased (2- to 5-fold) the tyrosine phosphorylation of GHR, JAK2, STAT5b, and ERK1/2, IL-6 did not alter these phosphorylation events. However, nuclear protein from IL-6-treated cells demonstrated reduced STAT5 DNA binding (by EMSA) at 15 min (-20%) and 60 min (-43%) after GH stimulation. To determine whether IL-6 inhibits GH-inducible promoter activity, CWSV-1 cells were transfected with Spi 2.1 or prolactin receptor promoter luciferase vectors, incubated with or without IL-6, then stimulated with GH. The induction of both Spi 2.1 (7.5-fold) and prolactin receptor (4-fold) promoter activity by GH was inhibited by IL-6. In summary, IL-6 mediates hepatic GH resistance by a time-dependent inhibition of GH-inducible promoter activity that is associated with reductions in STAT5 DNA binding.
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Affiliation(s)
- Tamer A Ahmed
- Dept. of Surgery, H070, Pennsylvania State Univ, College of Medicine, Hershey, PA 17033, USA
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Labriola L, Ferreira GB, Montor WR, Demasi MAA, Pimenta DC, Lojudice FH, Genzini T, Goldberg AC, Eliaschewitz FG, Sogayar MC. Prolactin-induced changes in protein expression in human pancreatic islets. Mol Cell Endocrinol 2007; 264:16-27. [PMID: 17095147 DOI: 10.1016/j.mce.2006.10.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 10/02/2006] [Accepted: 10/03/2006] [Indexed: 11/26/2022]
Abstract
Ex vivo islet cell culture prior to transplantation appears as an attractive alternative for treatment of type 1 diabetes. Previous results from our laboratory have demonstrated beneficial effects of human prolactin (rhPRL) treatment on human islet primary cultures. In order to probe into the molecular events involved in the intracellular action of rhPRL in these cells, we set out to identify proteins with altered expression levels upon rhPRL cell treatment, using two-dimensional (2D) gel electrophoresis and mass spectrometry (MS). An average of 300 different protein spots were detected, 14 of which were modified upon rhPRL treatment (p<0.01), of which 12 were successfully identified using MS and grouped according to their biological functions. In conclusion, our study provides, for the first time, information about proteins that could be critically involved in PRL's action on human pancreatic islets, and facilitate identification of new and specific targets involved in islet cell function and proliferation.
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Affiliation(s)
- L Labriola
- Department of Biochemistry, Chemistry Institute, University of Sao Paulo, Av. Prof. Lineu Prestes, 748, Bloco 9 Superior Sala 964, São Paulo 05508-900 SP, Brazil
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Vasavada RC, Gonzalez-Pertusa JA, Fujinaka Y, Fiaschi-Taesch N, Cozar-Castellano I, Garcia-Ocaña A. Growth factors and beta cell replication. Int J Biochem Cell Biol 2005; 38:931-50. [PMID: 16168703 DOI: 10.1016/j.biocel.2005.08.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 07/20/2005] [Accepted: 08/10/2005] [Indexed: 01/08/2023]
Abstract
Recent studies have demonstrated that human islet allograft transplantation can be a successful therapeutic option in the treatment of patients with Type I diabetes. However, this impressive recent advance is accompanied by a very important constraint. There is a critical paucity of pancreatic islets or pancreatic beta cells for islet transplantation to become a large-scale therapeutic option in patients with diabetes. This has prompted many laboratories around the world to invigorate their efforts in finding ways for increasing the availability of beta cells or beta cell surrogates that potentially could be transplanted into patients with diabetes. The number of studies analyzing the mechanisms that govern beta cell proliferation and growth in physiological and pathological conditions has increased exponentially during the last decade. These studies exploring the role of growth factors, intracellular signaling molecules and cell cycle regulators constitute the substrate for future strategies aimed at expanding human beta cells in vitro and/or in vivo after transplantation. In this review, we describe the current knowledge on the effects of several beta cell growth factors that have been shown to increase beta cell proliferation and expand beta cell mass in vitro and/or in vivo and that they could be potentially deployed in an effort to increase the number of patients transplanted with islets. Furthermore, we also analyze in this review recent studies deciphering the relevance of these specific islet growth factors as physiological and pathophysiological regulators of beta cell proliferation and islet growth.
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Affiliation(s)
- Rupangi C Vasavada
- Division of Endocrinology, University of Pittsburgh, BST-E1140, PA 15261, USA
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Guo Y, Lu Y, Houle D, Robertson K, Tang Z, Kopchick JJ, Liu YL, Liu JL. Pancreatic islet-specific expression of an insulin-like growth factor-I transgene compensates islet cell growth in growth hormone receptor gene-deficient mice. Endocrinology 2005; 146:2602-9. [PMID: 15731363 DOI: 10.1210/en.2004-1203] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Both GH and IGF-I stimulate islet cell growth, inhibit cell apoptosis, and regulate insulin biosynthesis and secretion. GH receptor gene deficiency (GHR(-/-)) caused diminished pancreatic islet cell mass and serum insulin level and elevated insulin sensitivity. Because IGF-I gene expression was nearly abolished in these mice, we sought to determine whether that had caused the islet defects. To restore IGF-I level, we have generated transgenic mice that express rat IGF-I cDNA under the direction of rat insulin promoter 1 (RIP-IGF). Using RNase protection assay and immunohistochemistry, the IGF-I transgene expression was revealed specifically in pancreatic islets of the RIP-IGF mice, which exhibited normal growth and development and possess no abnormalities in glucose homeostasis, insulin production, and islet cell mass. GHR(-/-) mice exhibited 50% reduction in the ratio of islet cell mass to body weight and increased insulin sensitivity but impaired glucose tolerance. Compared with GHR(-/-) alone, IGF-I overexpression on a GHR(-/-) background caused no change in the diminished blood glucose and serum insulin levels, pancreatic insulin contents, and insulin tolerance but improved glucose tolerance and insulin secretion. Remarkably, islet-specific overexpression of IGF-I gene in GHR(-/-) mice restored islet cell mass, at least partially through cell hypertrophy. Interestingly, double-transgenic male mice demonstrated a transient rescue in growth rates vs. GHR(-/-) alone, at 2-3 months of age. Our results suggest that IGF-I deficiency is part of the underlying mechanism of diminished islet growth in GHR(-/-) mice and are consistent with the notion that IGF-I mediates GH-induced islet cell growth.
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Affiliation(s)
- Yubin Guo
- Fraser Laboratories, Room M3-15, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, Quebec, Canada H3A 1A1
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Soboleva TK, Vetharaniam I, Nixon AJ, Montenegro R, Pearson AJ, Sneyd J. Mathematical modelling of prolactin-receptor interaction and the corollary for prolactin receptor gene expression in skin. J Theor Biol 2005; 234:289-98. [PMID: 15757685 DOI: 10.1016/j.jtbi.2004.11.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Revised: 11/03/2004] [Accepted: 11/17/2004] [Indexed: 11/25/2022]
Abstract
A mathematical model of prolactin regulating its own receptors was developed, and compared with experimental data on a qualitative level. The model incorporates the kinetics of prolactin-receptor interactions and subsequent signalling by prolactin-receptor dimers to regulate the production of receptor mRNA and hence the receptor population. The model relates changes in plasma prolactin concentration to prolactin receptor (PRLR) gene expression, and can be used for predictive purposes. The cell signalling that leads to the activation of target genes, and the mechanisms for regulation of transcription, were treated empirically in the model. The model's parameters were adjusted so that model simulations agreed with experimentally observed responses to administration of prolactin in sheep. In particular, the model correctly predicts insensitivity of receptor mRNA regulation to a series of subcutaneous injections of prolactin, versus sensitivity to prolonged infusion of prolactin. In the latter case, response was an acute down-regulation followed by a prolonged up-regulation of mRNA, with the magnitude of the up-regulation increasing with the duration of infusion period. The model demonstrates the feasibility of predicting the in vivo response of prolactin target genes to external manipulation of plasma prolactin, and could provide a useful tool for identifying optimal prolactin treatments for desirable outcomes.
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Affiliation(s)
- T K Soboleva
- AgResearch Ltd., Ruakura Research Centre, Private Bag 3123, Hamilton 2020, New Zealand.
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Corbacho AM, Valacchi G, Kubala L, Olano-Martín E, Schock BC, Kenny TP, Cross CE. Tissue-specific gene expression of prolactin receptor in the acute-phase response induced by lipopolysaccharides. Am J Physiol Endocrinol Metab 2004; 287:E750-7. [PMID: 15186999 DOI: 10.1152/ajpendo.00522.2003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Acute inflammation can elicit a defense reaction known as the acute-phase response (APR) that is crucial for reestablishing homeostasis in the host. The role for prolactin (PRL) as an immunomodulatory factor maintaining homeostasis under conditions of stress has been proposed; however, its function during the APR remains unclear. Previously, it was shown that proinflammatory cytokines characteristic of the APR (TNF-alpha, IL-1beta, and IFNgamma) induced the expression of the PRL receptor (PRLR) by pulmonary fibroblasts in vitro. Here, we investigated the in vivo expression of PRLR during lipopolysaccharide (LPS)-induced APR in various tissues of the mouse. We show that PRLR mRNA and protein levels were downregulated in hepatic tissues after intraperitoneal LPS injection. Downregulation of PRLR in the liver was confirmed by immunohistochemistry. A suppressive effect on mRNA expression was also observed in prostate, seminal vesicle, kidney, heart, and lung tissues. However, PRLR mRNA levels were increased in the thymus, and no changes were observed in the spleen. The proportion of transcripts for the different receptor isoforms (long, S1, S2, and S3) in liver and thymus was not altered by LPS injection. These findings suggest a complex tissue-specific regulation of PRLR expression in the context of the APR.
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Affiliation(s)
- Ana M Corbacho
- Division of Pulmonary and Critical Care Medicine, University of California, Davis 95616, USA.
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29
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Brelje TC, Stout LE, Bhagroo NV, Sorenson RL. Distinctive roles for prolactin and growth hormone in the activation of signal transducer and activator of transcription 5 in pancreatic islets of langerhans. Endocrinology 2004; 145:4162-75. [PMID: 15142985 DOI: 10.1210/en.2004-0201] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Although the beta-cells of the pancreatic islets of Langerhans express both prolactin (PRL) and GH receptors, we have observed that PRL is considerably more effective than GH in the up-regulation of islet function in vitro. This study examined whether differences in the activation of the Janus kinase 2/signal transducer and activator of transcription (STAT) 5 signaling pathway by these closely related receptors may be involved in this disparity. The activation of STAT5B by PRL was biphasic, with an initial peak within 30 min, a nadir between 1 and 3 h, and prolonged activation after 4 h. In contrast, the response to GH was transient for 1 h. The importance of the long-term activation of STAT5B by PRL was supported by the similar dose response curves for STAT5B activation and the PRL-induced increases in insulin secretion and islet cell proliferation. Because the pulsatile secretion of GH affects its actions in other target tissues, the ability of pretreatment with either hormone to affect subsequent stimulation was also examined. Surprisingly, the response to PRL was inhibited by prior exposure for less than 3 h to either PRL or GH and disappeared with a longer pretreatment with either hormone. Similar to other tissues, the response to GH was inhibited by any length of prior exposure to GH. However, pretreatment with PRL had no effect. These experiments are the first demonstration of the transient desensitization of the PRL receptor by either PRL or GH pretreatment in any tissue and the desensitization of GH stimulation in islet cells. These observations provide insight into the mechanisms that regulate the desensitization of these receptors and, more importantly, allow the long-term activation of STAT5B by the PRL receptor. These results may apply to other members of the cytokine superfamily of receptors. We also demonstrate that the increase in islet cell proliferation required continuous stimulation with PRL, whereas the smaller effect with GH occurred with either continuous or pulsatile stimulation. In summary, this study demonstrates that islets are sensitive to the temporal pattern of stimulation by these hormones and provides a new basis for understanding their physiological roles in the regulation of islet function.
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Affiliation(s)
- T Clark Brelje
- Department of Genetics, Cell Biology and Development, University of Minnesota Medical School, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
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Bordin S, Amaral MEC, Anhê GF, Delghingaro-Augusto V, Cunha DA, Nicoletti-Carvalho JE, Boschero AC. Prolactin-modulated gene expression profiles in pancreatic islets from adult female rats. Mol Cell Endocrinol 2004; 220:41-50. [PMID: 15196698 DOI: 10.1016/j.mce.2004.04.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 02/12/2004] [Accepted: 04/01/2004] [Indexed: 10/26/2022]
Abstract
The effects of prolactin (PRL) on transcript profile expression in 24h cultured pancreatic adult rat islets were investigated by cDNA expression array analysis to identify possible candidate mRNA species that encode proteins involved in the maturation and growth of the endocrine pancreas. The expression of 54 out of 588 genes was altered by treatment with PRL. The differentially expressed transcripts identified were distributed in six main categories involved in cell proliferation and differentiation, namely, cell cycle regulation, signal transduction, transcription factors and coactivators, translational machinery, Ca(2+)-mediated exocytosis, and immuno-response. Treatment with PRL also reduced the expression of genes related to apoptosis. Several genes, whose expression was previously not known to be modulated by PRL were also identified including macrophage migration inhibitory factor and Ca(2+)/calmodulin-dependent protein kinase IV. These genes have recently been shown to play a crucial role in insulin secretion and insulin gene expression, respectively. Treatment with PRL also modified the expression of AKT2 and bone morphogenetic protein receptor 1A that control glucose homeostasis and directly affect the behavior of endocrine pancreas and/or the sensitivity of target tissues to insulin. In conclusion, PRL induces several patterns of gene expression in pancreatic islet cells. The analysis of these different patterns will be useful for understanding the complex mechanism of action of PRL in the maturation and differentiation of pancreatic islets.
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Affiliation(s)
- Silvana Bordin
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), 05508-900 São Paulo, SP, Brazil.
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31
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Gutzman JH, Miller KK, Schuler LA. Endogenous human prolactin and not exogenous human prolactin induces estrogen receptor alpha and prolactin receptor expression and increases estrogen responsiveness in breast cancer cells. J Steroid Biochem Mol Biol 2004; 88:69-77. [PMID: 15026085 DOI: 10.1016/j.jsbmb.2003.10.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2003] [Accepted: 10/27/2003] [Indexed: 01/12/2023]
Abstract
Prolactin (PRL) and estrogen act synergistically to increase mammary gland growth, development, and differentiation. Based on their roles in the normal gland, these hormones have been studied to determine their interactions in the development and progression of breast cancer. However, most studies have evaluated only endocrine PRL and did not take into account the recent discovery that PRL is synthesized by human mammary cells, permitting autocrine/paracrine activity. To examine the effects of this endogenous PRL, we engineered MCF7 cells to inducibly overexpress human prolactin (hPRL). Using this Tet-On MCF7hPRL cell line, we studied effects on cell growth, PRLR, ER alpha, and PgR levels, and estrogen target genes. Induced endogenous hPRL, but not exogenous hPRL, increased ER alpha levels as well as estrogen responsiveness in these cells, suggesting that effects on breast cancer development and progression by estrogen may be amplified by cross-regulation of ER alpha levels by endogenous hPRL. The long PRLR isoform was also upregulated by endogenous, but not exogenous PRL. This model will allow investigation of endogenous hPRL in mammary epithelial cells and will enable further dissection of PRL effects on other hormone signaling pathways to determine the role of PRL in breast cancer.
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Affiliation(s)
- Jennifer H Gutzman
- Department of Comparative Biosciences, 2015 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, USA
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Stocco C, Djiane J, Gibori G. Prostaglandin F(2alpha) (PGF(2alpha)) and prolactin signaling: PGF(2alpha)-mediated inhibition of prolactin receptor expression in the Corpus luteum. Endocrinology 2003; 144:3301-5. [PMID: 12865306 DOI: 10.1210/en.2003-0420] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well established that prolactin (PRL) sustains, whereas prostaglandin F(2alpha) (PGF(2alpha)) curtails, progesterone production by the rodent corpus luteum (CL). We have previously shown that PGF(2alpha) inhibits the expression of several luteal genes stimulated by PRL, whereas it stimulates other genes inhibited by this hormone. We have also found that PGF(2alpha) stimulation of 20alpha-hydroxysteroid dehydrogenase (20alphaHSD), an enzyme that catabolizes progesterone, at the end of pregnancy is accompanied by a dramatic decrease in PRL receptor (PRL-R) expression. These findings, and the fact that the factors that inhibit PRL-R are not known, led us to examine in vivo whether the decline in PRL-R at the end of pregnancy is due to PGF(2alpha) and to also find out whether PGF(2alpha) opposes PRL action by inhibiting PRL-R expression. Using the PGF(2alpha) receptor (PGF(2alpha)-R) knockout, we examined whether the absence of the PGF(2alpha)-R prevents the decline in the expression of both the short and long forms of the PRL-R in the CL. We found that, in sharp contrast to the wild-type mice, in which both forms of the PRL-R decline to low levels between d 18-20 of pregnancy, expression of these receptors remained elevated in the PGF(2alpha)-R null mice. Furthermore, administration of PGF(2alpha) to pregnant rats inhibited PRL-R expression. Time-course analysis revealed that PGF(2alpha) treatment decreases both isoforms of PRL-R within 1 h of treatment in vivo, whereas its stimulatory effect on 20alphaHSD expression was further delayed. Similar results were obtained with luteinized granulosa cells in culture. To examine whether the decline in PRL-R is involved/necessary for PGF(2alpha) action, cells were transfected with a constitutively active PRL-R. The expression of this receptor did not prevent PGF(2alpha) effect on PRL-R or 20alphaHSD expression. Taken together, these results demonstrate that PGF(2alpha) inhibits the expression of the PRL-R and that the decline in both forms of the PRL-R that occurs at the end of pregnancy in the CL is due to PGF(2alpha). The results further suggest that PGF(2alpha)-mediated stimulation of 20alphaHSD is independent from PGF(2alpha) inhibition of PRL signaling in luteal cell.
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Affiliation(s)
- Carlos Stocco
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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Friedrichsen BN, Richter HE, Hansen JA, Rhodes CJ, Nielsen JH, Billestrup N, Møldrup A. Signal transducer and activator of transcription 5 activation is sufficient to drive transcriptional induction of cyclin D2 gene and proliferation of rat pancreatic beta-cells. Mol Endocrinol 2003; 17:945-58. [PMID: 12586844 DOI: 10.1210/me.2002-0356] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Signal transducer and activator of transcription 5 (STAT5) activation plays a central role in GH- and prolactin-mediated signal transduction in the pancreatic beta-cells. In previous experiments we demonstrated that STAT5 activation is necessary for human (h)GH-stimulated proliferation of INS-1 cells and hGH-induced increase of mRNA-levels of the cell cycle regulator cyclin D2. In this study we have further characterized the role of STAT5 in the regulation of cyclin D expression and beta-cell proliferation by hGH. Cyclin D2 mRNA and protein levels (but not cyclin D1 and D3) were induced in a time-dependent manner by hGH in INS-1 cells. Inhibition of protein synthesis by coincubation with cycloheximide did not affect the hGH-induced increase of cyclin D2 mRNA levels at 4 h. Expression of a dominant negative STAT5 mutant, STAT5aDelta749, partially inhibited cyclin D2 protein levels. INS-1 cells transiently transfected with a cyclin D2 promoter-reporter construct revealed a 3- to 5-fold increase of transcriptional activity in response to hGH stimulation. Furthermore, coexpression of a constitutive active STAT5 mutant (either CA-STAT5a or CA-STAT5b) was sufficient to drive transactivation of the promoter. CA-STAT5b was stably expressed in INS-1 cells under the control of a doxycycline-inducible promoter. Gel retardation experiments using a probe representing a putative STAT5 binding site in the cyclin D2 promoter revealed binding of the doxycycline-induced CA-STAT5b. Furthermore, induction of CA-STAT5b stimulated transcriptional activation of the cyclin D2 promoter and induced hGH-independent proliferation in these cells. In primary beta-cells, adenovirus-mediated expression of CA-STAT5b profoundly stimulated DNA-synthesis (5.3-fold over control) in the absence of hGH. Our studies indicate that STAT5 activation is sufficient to drive proliferation of the beta-cells and that cyclin D2 may be a critical target gene for STAT5 in this process.
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Liby K, Neltner B, Mohamet L, Menchen L, Ben-Jonathan N. Prolactin overexpression by MDA-MB-435 human breast cancer cells accelerates tumor growth. Breast Cancer Res Treat 2003; 79:241-52. [PMID: 12825859 DOI: 10.1023/a:1023956223037] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Prolactin (PRL) is an important hormone in mammary tumorigenesis in rodents but its involvement in human breast cancer has been controversial. A role for locally produced PRL in breast carcinogenesis is suggested by its mitogenic action on breast cancer cells and the expression of both PRL and its receptor (PRL-R) in breast carcinomas. Our objective was to examine whether PRL, overexpressed by breast cancer cells, forms an autocrine/paracrine loop that confers a growth advantage for tumors. MDA-MB-435 breast cancer cells overexpressing 23K human PRL were generated, and PRL production and secretion by the clones were confirmed by RT-PCR, western blotting, and the Nb2 bioassay; control clones contain vector only. In vitro the 23K PRL clones proliferated faster and expressed higher levels of the PRL-R protein than controls only when incubated in charcoal-stripped serum (CSS) devoid of lactogenic hormones. When injected into the mammary fatpad of female nude mice or subcutaneously into males, the PRL-overexpressing clones formed tumors that grew 2-4-fold faster than tumors derived from control clones or wild type MDA-MB-435 cells. Western analysis demonstrated significantly higher PRL, PRL-R, and bcl-2 levels in the tumors overexpressing PRL compared to control tumors. These data support a role for breast PRL as a growth/anti-apoptotic factor and suggest that it may serve as a novel therapeutic target for the treatment of breast cancer.
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Affiliation(s)
- Karen Liby
- Department of Cell Biology, University of Cincinnati Medical School, Cincinnati, OH 45267-0521, USA
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35
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Pi X, Zhang B, Li J, Voogt JL. Promoter usage and estrogen regulation of prolactin receptor gene in the brain of the female rat. Neuroendocrinology 2003; 77:187-97. [PMID: 12673052 DOI: 10.1159/000069510] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2002] [Accepted: 01/07/2003] [Indexed: 11/19/2022]
Abstract
Mechanisms underlying hormonal regulation of prolactin receptor (PRL-R) gene in the brain are unknown. The 5'-untranslated region of PRL-R mRNA in peripheral tissues contains at least three alternative first exons (1A, B, C) that are expressed as tissue-specific, suggesting the differential usage of PRL-R gene promoters. The present study aimed to investigate: (1). the possible regulation of PRL-R mRNA levels by estrogen in in vitro and in vivo tissues; (2). which exon (1A, or 1B, or 1C)-containing PRL-R mRNA transcript is expressed in the brain, and (3). how the specific exon 1-containing mRNA is affected by estrogen by using RT-PCR, Southern blot and 5'Race PCR techniques. The RT-PCR results showed that PRL-R mRNA was detected in the cerebral cortex and pons medulla in addition to the choroid plexus and hypothalamus in the female rat. The expression of PRL-R mRNA was up-regulated by estrogen treatment in the rat brain tissue and in the GT1-7 cell culture. Both exon 1A- and 1C-containing transcripts were expressed in all four regions, suggesting that promoters 1A and 1C for the PRL-R gene are utilized in the rat brain. Exon 1A-containing transcript was up-regulated by estrogen treatment in all four brain regions, whereas Exon 1C-containing transcript was up-regulated by estrogen treatment in 3 of the 4 brain regions, cerebral cortex being the exception. Exon 1B-containing transcript was neither detectable nor induced by estrogen treatment in any of the brain regions examined. The RT-PCR results were confirmed by partial isolation of 5'-untranslated regions of exon 1A- and 1C-containing PRL-R mRNA transcripts from brain tissue by using 5'Race PCR. The present result confirms the expression of PRL-R mRNA in the cerebral cortex and pons medulla in the female rat. The levels of PRL-R mRNA were up-regulated by estrogen in rat brain tissue and GT1-7 cell cultures. Detection of exon 1A- and 1C-containing transcripts implies that the promoter 1A and 1C are active in the female rat brain. Estrogen differentially regulates expression of the PRL-R mRNA in the different brain regions by increasing the utilization of PRL-R gene promoters 1A and 1C in the female rat.
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Affiliation(s)
- Xiujun Pi
- Department of Molecular and Integrative Physiology, Kansas University Medical Center, Kansas City, Kansas 66160-7401, USA
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Curlewis JD, Tam SP, Lau P, Kusters DHL, Barclay JL, Anderson ST, Waters MJ. A prostaglandin f(2alpha) analog induces suppressors of cytokine signaling-3 expression in the corpus luteum of the pregnant rat: a potential new mechanism in luteolysis. Endocrinology 2002; 143:3984-93. [PMID: 12239110 DOI: 10.1210/en.2002-220344] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PRL and placental lactogen (PL) play key roles in maintaining the rodent corpus luteum through pregnancy. Suppressors of cytokine signaling (SOCS) have been shown to decrease cell sensitivity to cytokines, including PRL, and so here we have addressed the issue of whether luteolysis induced by prostaglandin F(2alpha) (PGF(2alpha)) might up-regulate SOCS proteins to inhibit PRL signaling. In d 19 pregnant rats, cloprostenol, a PGF(2alpha) analog, rapidly induced transcripts for SOCS-3 and, to a lesser extent, SOCS-1. We also found increased SOCS-3 protein in the ovary by immunoblot and in the corpus luteum by immunohistochemistry. Increased SOCS-3 expression was preceded by an increase in STAT3 tyrosine phosphorylation 10 min after cloprostenol injection and was maintained for 4 h, as determined by gel shift and immunohistochemistry. Induction of SOCS-3 was accompanied by a sharp decrease in active STAT5, as determined by gel-shift assay and by loss of nuclear localized STAT5. Four hours after cloprostenol administration, the corpus luteum was refractory to stimulation of STAT5 by PRL administration, and this was not due to down-regulation of PRL receptor. Therefore, induction of SOCS-3 by PGF(2alpha) may be an important element in the initiation of luteolysis via rapid suppression of luteotropic support from PL.
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Affiliation(s)
- J D Curlewis
- School of Biomedical Sciences, Department of Physiology and Pharmacology, University of Queensland, Australia.
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Jacobsen BM, Richer JK, Schittone SA, Horwitz KB. New human breast cancer cells to study progesterone receptor isoform ratio effects and ligand-independent gene regulation. J Biol Chem 2002; 277:27793-800. [PMID: 12021276 DOI: 10.1074/jbc.m202584200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All known progesterone target cells coexpress two functionally different progesterone receptor (PR) isoforms: 120-kDa B-receptors (PR-B) and N-terminally truncated, 94-kDa A-receptors (PR-A). Their ratio varies in normal and malignant tissues. In human breast cancer cells, homodimers of progesterone-occupied PR-A or PR-B regulate different gene subsets. To study PR homo- and heterodimers, we constructed breast cancer cell lines in which isoform expression is controlled by an inducible system. PR-negative cells or cells that stably express one or the other isoform were used to construct five sets of cells: (i) PR-negative control cells (Y iNull), (ii) inducible PR-A cells (Y iA), (iii) inducible PR-B cells (Y iB), (iv) stable PR-B plus inducible PR-A cells (B iA), and (v) stable PR-A plus inducible PR-B cells (A iB). Expression levels of each isoform and/or the PR-A/PR-B ratios could be tightly controlled by the dose of inducer as demonstrated by immunoblotting and transcription studies. Induced PRs underwent normal progestin-dependent phosphorylation and down-regulation and regulated exogenous promoters as well as endogenous gene expression. Transcription of exogenous promoters was dependent on the PR-A/PR-B ratio, whereas transcription of endogenous genes was more complex. Finally, we have described several genes that are regulated by induced PR-A even in the absence of ligand.
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Affiliation(s)
- Britta M Jacobsen
- Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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Brelje TC, Svensson AM, Stout LE, Bhagroo NV, Sorenson RL. An immunohistochemical approach to monitor the prolactin-induced activation of the JAK2/STAT5 pathway in pancreatic islets of Langerhans. J Histochem Cytochem 2002; 50:365-83. [PMID: 11850439 DOI: 10.1177/002215540205000308] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This study examined whether an immunohistochemical method examining the subcellular localization of STAT5 could be used to characterize the activation of the JAK2/STAT5 pathway by prolactin (PRL) in intact cells or tissues. In the Ins-1 beta-cell line, STAT5A and STAT5B were distributed almost equally in the cytoplasm and the nucleus in unstimulated cells. STAT5A was also detected along the border of cells and in the perinuclear region. After exposure to PRL, the redistribution from the cytoplasm to the nucleus was much higher for STAT5B compared to STAT5A. This translocation represented 12% of the STAT5A and 22% of the STAT5B originally located in the cytoplasm before stimulation. In isolated rat islets of Langerhans, PRL stimulated the nuclear translocation of both STAT5A and STAT5B only in beta-cells. The expression of the PRL receptor only by beta-cells was confirmed with a rabbit polyclonal antiserum raised against the rat PRL receptor. It was estimated that 4% of STAT5A and 9% of STAT5B originally located in the cytoplasm was translocated to the nucleus after stimulation. The presence of a functional JAK2/STAT5 signaling pathway in all islet cells was demonstrated by the nuclear translocation of STAT5B in all islet cells (i.e., alpha-, beta-, and delta-cells) after stimulation with fetal calf serum. The nuclear translocation and tyrosine phosphorylation of STAT5B was biphasic, with an initial peak within 30 min, a nadir between 1 and 3 hr, and prolonged activation after 4 hr. In contrast, the tyrosine phosphorylation of STAT5A was also biphasic but its nuclear translocation peaked within 30 min and was then reduced to a level slightly above that observed before PRL stimulation. This method is able to detect changes in STAT5 activation as small as 2% of the total cell content. These observations demonstrate the utility of this approach for studying the activation of STAT5 in a mixed population of cells within tissues or organs. In addition, the dose response for the nuclear translocation of STAT5B in normal beta-cells was similar to those for changes in proliferation and insulin secretion in isolated rat islets. Therefore, the subcellular localization can be used to monitor the activation of STAT5 and it may be a key event in the upregulation of the pancreatic islets of Langerhans during pregnancy.
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Affiliation(s)
- T Clark Brelje
- Department of Genetics, Cell Biology and Development, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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Abstract
In mouse mammary epithelial cells, prolactin transiently elevates nitric oxide (NO) to a maximum of 6 nmol/mg protein at 15 min, after which levels fall rapidly. This stimulation can be achieved by as little as 100 ng prolactin/ml and can be mimicked by 100 microg sodium nitroprusside/ml. NO is both necessary and sufficient to mediate the prolactin-induced redistribution of its receptor from internal pools to the cell surface. NO can also enhance DNA synthesis stimulated by submaximal prolactin concentrations (50 ng/ml), but it is not necessary at pharmacological prolactin concentrations (1 microg/ml). In contrast, NO completely inhibits alpha-lactalbumin production. In summary, prolactin transiently elevates NO to enhance DNA synthesis and suppress premature differentiation; thereafter, NO declines, DNA synthesis ceases and differentiation proceeds. This data suggest that NO may mediate some of the effects of prolactin on growth in the mammary gland.
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Affiliation(s)
- F F Bolander
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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Ehret GB, Reichenbach P, Schindler U, Horvath CM, Fritz S, Nabholz M, Bucher P. DNA binding specificity of different STAT proteins. Comparison of in vitro specificity with natural target sites. J Biol Chem 2001; 276:6675-88. [PMID: 11053426 DOI: 10.1074/jbc.m001748200] [Citation(s) in RCA: 301] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
STAT transcription factors are expressed in many cell types and bind to similar sequences. However, different STAT gene knock-outs show very distinct phenotypes. To determine whether differences between the binding specificities of STAT proteins account for these effects, we compared the sequences bound by STAT1, STAT5A, STAT5B, and STAT6. One sequence set was selected from random oligonucleotides by recombinant STAT1, STAT5A, or STAT6. For another set including many weak binding sites, we quantified the relative affinities to STAT1, STAT5A, STAT5B, and STAT6. We compared the results to the binding sites in natural STAT target genes identified by others. The experiments confirmed the similar specificity of different STAT proteins. Detailed analysis indicated that STAT5A specificity is more similar to that of STAT6 than that of STAT1, as expected from the evolutionary relationships. The preference of STAT6 for sites in which the half-palindromes (TTC) are separated by four nucleotides (N(4)) was confirmed, but analysis of weak binding sites showed that STAT6 binds fairly well to N(3) sites. As previously reported, STAT1 and STAT5 prefer N(3) sites; however, STAT5A, but not STAT1, weakly binds N(4) sites. None of the STATs bound to half-palindromes. There were no specificity differences between STAT5A and STAT5B.
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Affiliation(s)
- G B Ehret
- Swiss Institute for Experimental Cancer Research (ISREC) 1066 Epalinges, Switzerland.
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Nevalainen MT, Ahonen TJ, Yamashita H, Chandrashekar V, Bartke A, Grimley PM, Robinson GW, Hennighausen L, Rui H. Epithelial defect in prostates of Stat5a-null mice. J Transl Med 2000; 80:993-1006. [PMID: 10908145 DOI: 10.1038/labinvest.3780105] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The transcription factor Stat5a critically mediates prolactin (PRL)-induced mammary gland development and lactogenesis. PRL also stimulates growth and differentiation of prostate tissue. Specifically, hyperprolactinemia gives rise to prostate hyperplasia, and prostate size is reduced in PRL-deficient mice. We therefore investigated the importance of Stat5a for prostate development and function by examining Stat5a-null mice. The absence of Stat5a in mice was associated with a distinct prostate morphology characterized by an increased prevalence of local disorganization within acinar epithelium of ventral prostates. Affected acini were typically filled with desquamated, granular epithelial cells that had become embedded in dense, coagulated secretory material. These features were reminiscent of acinar cyst formation and degeneration frequently observed in human benign prostate hyperplasia, however, cystic changes in prostate acini of Stat5a-deficient mice were not associated with increased prostate size or morphologic hallmarks of epithelial hyperplasia. Instead, immunohistochemistry of the prostate-specific secretory marker, probasin, suggested that hypersecretory function of the epithelium could underlie local congestion and cyst formation in prostates of Stat5a-null mice. Serum testosterone and PRL levels were normal in Stat5a knockout mice, but prostate PRL receptor expression was reduced as determined by immunohistochemistry. Expression levels or activation states of other PRL signal transduction proteins, including Stat5b, Stat3, Stat1, ERK1, and ERK2 were not altered. The present study offers the first evidence for a direct role of Stat5a in the maintenance of normal tissue architecture and function of the mouse prostate.
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Affiliation(s)
- M T Nevalainen
- Department of Pathology, Uniformed Services University of the Health Sciences, and National Institutes of Diabetes and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Stewart MD, Johnson GA, Gray CA, Burghardt RC, Schuler LA, Joyce MM, Bazer FW, Spencer TE. Prolactin receptor and uterine milk protein expression in the ovine endometrium during the estrous cycle and pregnancy. Biol Reprod 2000; 62:1779-89. [PMID: 10819783 DOI: 10.1095/biolreprod62.6.1779] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Lactogenic hormones regulate epithelial proliferation, differentiation, and function in a variety of epitheliomesenchymal organs. During pregnancy, the ovine uterus is a potential site for endocrine and paracrine actions of lactogenic hormones in the form of pituitary prolactin (PRL) and placental lactogen (PL). These studies determined temporal and spatial alterations in PRL receptor (PRL-R) and expression of uterine milk proteins (UTMP), a marker of endometrial secretory activity, in the ovine endometrium during the estrous cycle and pregnancy. Slot-blot hybridization analysis indicated that steady-state levels of endometrial PRL-R mRNA increased during pregnancy. In situ hybridization and immunohistochemical analyses indicated that PRL-R mRNA and protein were exclusively expressed in the endometrial glandular epithelium (GE). No PRL-R mRNA expression was detected in luminal epithelium, stroma, myometrium, or conceptus trophectoderm. Reverse transcription-polymerase chain reaction analyses determined that the endometrial GE expressed both long and short alternative splice forms of the ovine PRL-R gene. Slot-blot hybridization analysis indicated that steady-state levels of intercaruncular endometrial UTMP mRNA increased about 3-fold between Days 20 and 60, increased another 3-fold between Days 60 and 80, and then declined slightly to Day 120. In pregnant ewes, UTMP mRNA expression was restricted to the endometrial GE in the stratum spongiosum (sGE), increased substantially between Days 15 and 17, and, between Days 17 to 50 of gestation, was markedly higher in upper than lower sGE. After Day 50, hyperplasia of the sGE was accompanied by increased UTMP mRNA expression by all sGE. Collectively, results indicate that 1) endometrial sGE is a primary target for actions of lactogenic hormones and 2) UTMP mRNA expression is correlated with PL production by the trophectoderm and state of sGE differentiation during pregnancy. It is proposed that activation of PRL-R signal transduction pathways by PRL and PL plays a major role in endometrial GE remodeling and differentiated function during pregnancy in support of conceptus growth and development.
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Affiliation(s)
- M D Stewart
- Center for Animal Biotechnology and Genomics, Albert B. Alkek Institute of Biosciences and Technology, Texas A&M University System Health Science Center and Department of Animal Science, Texas A&M University, College Station, Texas 77843-2471, USA
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