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O'Hara L, Christian HC, Le Tissier P, Smith LB. Hyperprolactinemia in a male pituitary androgen receptor knockout mouse is associated with female-like lactotroph development. Andrology 2021; 9:1652-1661. [PMID: 33998165 DOI: 10.1111/andr.13040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 04/28/2021] [Accepted: 05/12/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Circulating prolactin concentration in rodents and humans is sexually dimorphic. Oestrogens are a well-characterised stimulator of prolactin release. Circulating prolactin fluctuates throughout the menstrual/oestrous cycle of females in response to oestrogen levels, but remains continually low in males. We have previously identified androgens as an inhibitor of prolactin release through characterisation of males of a mouse line with a conditional pituitary androgen receptor knockout (PARKO) which have an increase in circulating prolactin, but unchanged lactotroph number. OBJECTIVES In the present study, we aimed to specify the cell type that androgens act on to repress prolactin release. MATERIALS AND METHODS PARKO, lactotroph-specific, Pit1 lineage-specific and neural-specific conditional androgen receptor knockout male mice were investigated using prolactin ELISA, pituitary electron microscopy, immunohistochemistry and qRT-PCR. RESULTS Lactotroph-specific, Pit1 lineage-specific and neural-specific conditional AR knockouts did not duplicate the high circulating prolactin seen in the PARKO line. Using electron microscopy to examine ultrastructure, we showed that pituitary androgen receptor knockout male mice develop lactotrophs that resemble those seen in female mice. Castrated PARKO males have significantly reduced circulating prolactin compared to intact males. When expression of selected oestrogen-regulated anterior pituitary genes was examined, there were no differences in expression level between controls and knockouts. DISCUSSION The cell type that androgens act on to repress prolactin release is not the lactotroph, cells in the Pit1-lineage, or the dopaminergic neurons in the hypothalamus. PARKO males develop a female-specific lactotroph ultrastructure that this is likely to contribute to the increase in circulating prolactin. Castrated PARKO males have significantly reduced circulating prolactin compared to intact males, which suggests that removal of both circulating oestrogens and androgens reduces the stimulation of pituitary prolactin release. CONCLUSION Further investigation is needed into prolactin regulation by changes in androgen-oestrogen balance, which is involved sexual dimorphism of development and diseases including hyperprolactinemia.
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Affiliation(s)
- Laura O'Hara
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,MRC Centre for Reproductive Health, The Queen's Medical Research Institute, Edinburgh, UK.,ZJU-UoE Institute, Zhejiang University School of Medicine, Zhejiang University, Zhejiang, China
| | | | - Paul Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Lee B Smith
- MRC Centre for Reproductive Health, The Queen's Medical Research Institute, Edinburgh, UK.,School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
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2
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O'Hara L, Christian HC, Jeffery N, Le Tissier P, Smith LB. Characterisation of a mural cell network in the murine pituitary gland. J Neuroendocrinol 2020; 32:e12903. [PMID: 32959418 DOI: 10.1111/jne.12903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 08/03/2020] [Accepted: 08/21/2020] [Indexed: 11/29/2022]
Abstract
The anterior and intermediate lobes of the pituitary are composed of endocrine cells, as well as vasculature and supporting cells, such as folliculostellate cells. Folliculostellate cells form a network with several postulated roles in the pituitary, including production of paracrine signalling molecules and cytokines, coordination of endocrine cell hormone release, phagocytosis, and structural support. Folliculostellate cells in rats are characterised by expression of S100B protein, and in humans by glial fibrillary acid protein. However, there is evidence for another network of supporting cells in the anterior pituitary that has properties of mural cells, such as vascular smooth muscle cells and pericytes. The present study aims to characterise the distribution of cells that express the mural cell marker platelet derived growth factor receptor beta (PDGFRβ) in the mouse pituitary and establish whether these cells are folliculostellate. By immunohistochemical localisation, we determine that approximately 80% of PDGFRβ+ cells in the mouse pituitary have a non-perivascular location and 20% are pericytes. Investigation of gene expression in a magnetic cell sorted population of PDGFRβ+ cells shows that, despite a mostly non-perivascular location, this population is enriched for mural cell markers but not enriched for rat or human folliculostellate cell markers. This is confirmed by immunohistochemistry. The present study concludes that a mural cell network is present throughout the anterior pituitary of the mouse and that this population does not express well-characterised human or rat folliculostellate cell markers.
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Affiliation(s)
- Laura O'Hara
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Nathan Jeffery
- MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh, UK
| | - Paul Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Lee B Smith
- MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh, UK
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
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3
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Wood SH, Hindle MM, Mizoro Y, Cheng Y, Saer BRC, Miedzinska K, Christian HC, Begley N, McNeilly J, McNeilly AS, Meddle SL, Burt DW, Loudon ASI. Circadian clock mechanism driving mammalian photoperiodism. Nat Commun 2020; 11:4291. [PMID: 32855407 PMCID: PMC7453030 DOI: 10.1038/s41467-020-18061-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/27/2020] [Indexed: 12/19/2022] Open
Abstract
The annual photoperiod cycle provides the critical environmental cue synchronizing rhythms of life in seasonal habitats. In 1936, Bünning proposed a circadian-based coincidence timer for photoperiodic synchronization in plants. Formal studies support the universality of this so-called coincidence timer, but we lack understanding of the mechanisms involved. Here we show in mammals that long photoperiods induce the circadian transcription factor BMAL2, in the pars tuberalis of the pituitary, and triggers summer biology through the eyes absent/thyrotrophin (EYA3/TSH) pathway. Conversely, long-duration melatonin signals on short photoperiods induce circadian repressors including DEC1, suppressing BMAL2 and the EYA3/TSH pathway, triggering winter biology. These actions are associated with progressive genome-wide changes in chromatin state, elaborating the effect of the circadian coincidence timer. Hence, circadian clock-pituitary epigenetic pathway interactions form the basis of the mammalian coincidence timer mechanism. Our results constitute a blueprint for circadian-based seasonal timekeeping in vertebrates.
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Affiliation(s)
- S H Wood
- Centre for Biological Timing, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
- Arctic Chronobiology and Physiology Research Group, Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, 9037, Norway
| | - M M Hindle
- The Roslin Institute, and Royal (Dick) School of Veterinary Studies University of Edinburgh, Roslin, Midlothian, EH25 9PRG, UK
| | - Y Mizoro
- Centre for Biological Timing, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - Y Cheng
- UQ Genomics Initiative, The University of Queensland, Brisbane, QLD, 4072, Australia
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Camperdown, NSW, Australia
| | - B R C Saer
- Centre for Biological Timing, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - K Miedzinska
- The Roslin Institute, and Royal (Dick) School of Veterinary Studies University of Edinburgh, Roslin, Midlothian, EH25 9PRG, UK
| | - H C Christian
- University of Oxford, Department of Physiology, Anatomy and Genetics, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, UK
| | - N Begley
- Centre for Biological Timing, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - J McNeilly
- MRC Centre for Reproductive Health, Queen's Medical Research Institute, Edinburgh, EH16 4TJ, UK
| | - A S McNeilly
- MRC Centre for Reproductive Health, Queen's Medical Research Institute, Edinburgh, EH16 4TJ, UK
| | - S L Meddle
- The Roslin Institute, and Royal (Dick) School of Veterinary Studies University of Edinburgh, Roslin, Midlothian, EH25 9PRG, UK
| | - D W Burt
- The Roslin Institute, and Royal (Dick) School of Veterinary Studies University of Edinburgh, Roslin, Midlothian, EH25 9PRG, UK
- UQ Genomics Initiative, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - A S I Loudon
- Centre for Biological Timing, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK.
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4
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Hoerder-Suabedissen A, Korrell KV, Hayashi S, Jeans A, Ramirez DMO, Grant E, Christian HC, Kavalali ET, Wilson MC, Molnár Z. Cell-Specific Loss of SNAP25 from Cortical Projection Neurons Allows Normal Development but Causes Subsequent Neurodegeneration. Cereb Cortex 2020; 29:2148-2159. [PMID: 29850799 DOI: 10.1093/cercor/bhy127] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Indexed: 11/13/2022] Open
Abstract
Synaptosomal associated protein 25 kDa (SNAP25) is an essential component of the SNARE complex regulating synaptic vesicle fusion. SNAP25 deficiency has been implicated in a variety of cognitive disorders. We ablated SNAP25 from selected neuronal populations by generating a transgenic mouse (B6-Snap25tm3mcw (Snap25-flox)) with LoxP sites flanking exon5a/5b. In the presence of Cre-recombinase, Snap25-flox is recombined to a truncated transcript. Evoked synaptic vesicle release is severely reduced in Snap25 conditional knockout (cKO) neurons as shown by live cell imaging of synaptic vesicle fusion and whole cell patch clamp recordings in cultured hippocampal neurons. We studied Snap25 cKO in subsets of cortical projection neurons in vivo (L5-Rbp4-Cre; L6-Ntsr1-Cre; L6b-Drd1a-Cre). cKO neurons develop normal axonal projections, but axons are not maintained appropriately, showing signs of swelling, fragmentation and eventually complete absence. Onset and progression of degeneration are dependent on the neuron type, with L5 cells showing the earliest and most severe axonal loss. Ultrastructural examination revealed that cKO neurites contain autophagosome/lysosome-like structures. Markers of inflammation such as Iba1 and lipofuscin are increased only in adult cKO cortex. Snap25 cKO can provide a model to study genetic interactions with environmental influences in several disorders.
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Affiliation(s)
- Anna Hoerder-Suabedissen
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
| | - Kim V Korrell
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
| | - Shuichi Hayashi
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
| | | | - Denise M O Ramirez
- Department of Neuroscience, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, USA
| | - Eleanor Grant
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
| | - Ege T Kavalali
- Department of Neuroscience, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, USA.,Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, USA
| | - Michael C Wilson
- Department of Neurosciences, University of New Mexico, Albuquerque, NM, USA
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
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5
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Ren YA, Monkkonen T, Lewis MT, Bernard DJ, Christian HC, Jorgez CJ, Moore JA, Landua JD, Chin HM, Chen W, Singh S, Kim IS, Zhang XH, Xia Y, Phillips KJ, MacKay H, Waterland RA, Ljungberg MC, Saha PK, Hartig SM, Coll TF, Richards JS. S100a4-Cre-mediated deletion of Patched1 causes hypogonadotropic hypogonadism: role of pituitary hematopoietic cells in endocrine regulation. JCI Insight 2019; 5:126325. [PMID: 31265437 DOI: 10.1172/jci.insight.126325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hormones produced by the anterior pituitary gland regulate an array of important physiological functions, but pituitary hormone disorders are not fully understood. Herein we report that genetically-engineered mice with deletion of the hedgehog signaling receptor Patched1 by S100a4 promoter-driven Cre recombinase (S100a4-Cre;Ptch1fl/fl mutants) exhibit adult-onset hypogonadotropic hypogonadism and multiple pituitary hormone disorders. During the transition from puberty to adult, S100a4-Cre;Ptch1fl/fl mice of both sexes develop hypogonadism coupled with reduced gonadotropin levels. Their pituitary glands also display severe structural and functional abnormalities, as revealed by transmission electron microscopy and expression of key genes regulating pituitary endocrine functions. S100a4-Cre activity in the anterior pituitary gland is restricted to CD45+ cells of hematopoietic origin, including folliculo-stellate cells and other immune cell types, causing sex-specific changes in the expression of genes regulating the local microenvironment of the anterior pituitary. These findings provide in vivo evidence for the importance of pituitary hematopoietic cells in regulating fertility and endocrine function, in particular during sexual maturation and likely through sexually dimorphic mechanisms. These findings support a previously unrecognized role of hematopoietic cells in causing hypogonadotropic hypogonadism and provide inroads into the molecular and cellular basis for pituitary hormone disorders in humans.
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Affiliation(s)
- Yi Athena Ren
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Michael T Lewis
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Department of Radiology and.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, England
| | - Carolina J Jorgez
- Department of Urology, Baylor College of Medicine, Houston, Texas, USA
| | - Joshua A Moore
- Department of Urology, Baylor College of Medicine, Houston, Texas, USA
| | - John D Landua
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Department of Radiology and.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Haelee M Chin
- Department of Biology, Rice University, Houston, Texas, USA
| | - Weiqin Chen
- Department of Physiology, Augusta University, Augusta, Georgia, USA
| | - Swarnima Singh
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Ik Sun Kim
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Xiang Hf Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Yan Xia
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kevin J Phillips
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Harry MacKay
- USDA/ARS Children's Nutrition Research Center, Houston, Texas, USA
| | | | - M Cecilia Ljungberg
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Jan and Dan Duncan Neurological Research Center at Texas Children's Hospital, Houston, Texas, USA
| | - Pradip K Saha
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Sean M Hartig
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Tatiana Fiordelisio Coll
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, University of Montpellier, Montpellier, France.,Laboratorio de Neuroendocrinología Comparada, Departamento de Ecología y Recursos Naturales, Biología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City, Distrito Federal, México
| | - JoAnne S Richards
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
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6
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Momiji H, Hassall KL, Featherstone K, McNamara AV, Patist AL, Spiller DG, Christian HC, White MRH, Davis JRE, Finkenstädt BF, Rand DA. Disentangling juxtacrine from paracrine signalling in dynamic tissue. PLoS Comput Biol 2019; 15:e1007030. [PMID: 31194728 PMCID: PMC6592563 DOI: 10.1371/journal.pcbi.1007030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/25/2019] [Accepted: 04/15/2019] [Indexed: 11/18/2022] Open
Abstract
Prolactin is a major hormone product of the pituitary gland, the central endocrine regulator. Despite its physiological importance, the cell-level mechanisms of prolactin production are not well understood. Having significantly improved the resolution of real-time-single-cell-GFP-imaging, the authors recently revealed that prolactin gene transcription is highly dynamic and stochastic yet shows space-time coordination in an intact tissue slice. However, it still remains an open question as to what kind of cellular communication mediates the observed space-time organization. To determine the type of interaction between cells we developed a statistical model. The degree of similarity between two expression time series was studied in terms of two distance measures, Euclidean and geodesic, the latter being a network-theoretic distance defined to be the minimal number of edges between nodes, and this was used to discriminate between juxtacrine from paracrine signalling. The analysis presented here suggests that juxtacrine signalling dominates. To further determine whether the coupling is coordinating transcription or post-transcriptional activities we used stochastic switch modelling to infer the transcriptional profiles of cells and estimated their similarity measures to deduce that their spatial cellular coordination involves coupling of transcription via juxtacrine signalling. We developed a computational model that involves an inter-cell juxtacrine coupling, yielding simulation results that show space-time coordination in the transcription level that is in agreement with the above analysis. The developed model is expected to serve as the prototype for the further study of tissue-level organised gene expression for epigenetically regulated genes, such as prolactin.
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Affiliation(s)
- Hiroshi Momiji
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom, Mathematics Institute, University of Warwick, Coventry, United Kingdom
- * E-mail: (HM); (MRHW); (JRED); (BFF); (DAR)
| | - Kirsty L. Hassall
- Department of Statistics, University of Warwick, Coventry, United Kingdom
| | - Karen Featherstone
- Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
| | - Anne V. McNamara
- Systems Microscopy Centre, University of Manchester, Manchester, United Kingdom
| | - Amanda L. Patist
- Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
| | - David G. Spiller
- Systems Microscopy Centre, University of Manchester, Manchester, United Kingdom
| | - Helen C. Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Michael R. H. White
- Systems Microscopy Centre, University of Manchester, Manchester, United Kingdom
- * E-mail: (HM); (MRHW); (JRED); (BFF); (DAR)
| | - Julian R. E. Davis
- Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
- * E-mail: (HM); (MRHW); (JRED); (BFF); (DAR)
| | - Bärbel F. Finkenstädt
- Department of Statistics, University of Warwick, Coventry, United Kingdom
- * E-mail: (HM); (MRHW); (JRED); (BFF); (DAR)
| | - David A. Rand
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom, Mathematics Institute, University of Warwick, Coventry, United Kingdom
- * E-mail: (HM); (MRHW); (JRED); (BFF); (DAR)
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7
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Kar P, Mirams GR, Christian HC, Parekh AB. Control of NFAT Isoform Activation and NFAT-Dependent Gene Expression through Two Coincident and Spatially Segregated Intracellular Ca 2+ Signals. Mol Cell 2017; 64:746-759. [PMID: 27863227 PMCID: PMC5128683 DOI: 10.1016/j.molcel.2016.11.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 08/22/2016] [Accepted: 11/03/2016] [Indexed: 01/25/2023]
Abstract
Excitation-transcription coupling, linking stimulation at the cell surface to changes in nuclear gene expression, is conserved throughout eukaryotes. How closely related coexpressed transcription factors are differentially activated remains unclear. Here, we show that two Ca2+-dependent transcription factor isoforms, NFAT1 and NFAT4, require distinct sub-cellular InsP3 and Ca2+ signals for physiologically sustained activation. NFAT1 is stimulated by sub-plasmalemmal Ca2+ microdomains, whereas NFAT4 additionally requires Ca2+ mobilization from the inner nuclear envelope by nuclear InsP3 receptors. NFAT1 is rephosphorylated (deactivated) more slowly than NFAT4 in both cytoplasm and nucleus, enabling a more prolonged activation phase. Oscillations in cytoplasmic Ca2+, long considered the physiological form of Ca2+ signaling, play no role in activating either NFAT protein. Instead, effective sustained physiological activation of NFAT4 is tightly linked to oscillations in nuclear Ca2+. Our results show how gene expression can be controlled by coincident yet geographically distinct Ca2+ signals, generated by a freely diffusible InsP3 message. NFAT1 is activated by local Ca2+ entry, whereas NFAT4 also needs nuclear Ca2+ Nuclear Ca2+ increases via InsP3 receptors located on the inner nuclear membrane NFAT1 and NFAT4 show very different rephosphorylation (deactivation) kinetics Slow deactivation of NFAT1 affords a form of short-term memory to gene expression
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Affiliation(s)
- Pulak Kar
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Gary R Mirams
- Computational Biology, Department of Computer Science, University of Oxford, Parks Road, Oxford, OX1 3QD, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Anant B Parekh
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
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8
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Hopkins AL, Nelson TAS, Guschina IA, Parsons LC, Lewis CL, Brown RC, Christian HC, Davies JS, Wells T. Unacylated ghrelin promotes adipogenesis in rodent bone marrow via ghrelin O-acyl transferase and GHS-R 1a activity: evidence for target cell-induced acylation. Sci Rep 2017; 7:45541. [PMID: 28361877 PMCID: PMC5374529 DOI: 10.1038/srep45541] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/21/2017] [Indexed: 11/09/2022] Open
Abstract
Despite being unable to activate the cognate ghrelin receptor (GHS-R), unacylated ghrelin (UAG) possesses a unique activity spectrum that includes promoting bone marrow adipogenesis. Since a receptor mediating this action has not been identified, we re-appraised the potential interaction of UAG with GHS-R in the regulation of bone marrow adiposity. Surprisingly, the adipogenic effects of intra-bone marrow (ibm)-infused acylated ghrelin (AG) and UAG were abolished in male GHS-R-null mice. Gas chromatography showed that isolated tibial marrow adipocytes contain the medium-chain fatty acids utilised in the acylation of UAG, including octanoic acid. Additionally, immunohistochemistry and immunogold electron microscopy revealed that tibial marrow adipocytes show prominent expression of the UAG-activating enzyme ghrelin O-acyl transferase (GOAT), which is located in the membranes of lipid trafficking vesicles and in the plasma membrane. Finally, the adipogenic effect of ibm-infused UAG was completely abolished in GOAT-KO mice. Thus, the adipogenic action of exogenous UAG in tibial marrow is dependent upon acylation by GOAT and activation of GHS-R. This suggests that UAG is subject to target cell-mediated activation – a novel mechanism for manipulating hormone activity.
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Affiliation(s)
- Anna L Hopkins
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Timothy A S Nelson
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Irina A Guschina
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Lydia C Parsons
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Charlotte L Lewis
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Richard C Brown
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3QX, UK
| | - Jeffrey S Davies
- Institute of Life Science, School of Medicine, Swansea University, Swansea, SA2 8PP, UK
| | - Timothy Wells
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
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9
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Rider SA, Christian HC, Mullins LJ, Howarth AR, MacRae CA, Mullins JJ. Zebrafish mesonephric renin cells are functionally conserved and comprise two distinct morphological populations. Am J Physiol Renal Physiol 2017; 312:F778-F790. [PMID: 28179256 DOI: 10.1152/ajprenal.00608.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/17/2017] [Accepted: 02/01/2017] [Indexed: 12/20/2022] Open
Abstract
Zebrafish provide an excellent model in which to assess the role of the renin-angiotensin system in renal development, injury, and repair. In contrast to mammals, zebrafish kidney organogenesis terminates with the mesonephros. Despite this, the basic functional structure of the nephron is conserved across vertebrates. The relevance of teleosts for studies relating to the regulation of the renin-angiotensin system was established by assessing the phenotype and functional regulation of renin-expressing cells in zebrafish. Transgenic fluorescent reporters for renin (ren), smooth muscle actin (acta2), and platelet-derived growth factor receptor-beta (pdgfrb) were studied to determine the phenotype and secretory ultrastructure of perivascular renin-expressing cells. Whole kidney ren transcription responded to altered salinity, pharmacological renin-angiotensin system inhibition, and renal injury. Mesonephric ren-expressing cells occupied niches at the preglomerular arteries and afferent arterioles, forming intermittent epithelioid-like multicellular clusters exhibiting a granular secretory ultrastructure. In contrast, renin cells of the efferent arterioles were thin bodied and lacked secretory granules. Renin cells expressed the perivascular cell markers acta2 and pdgfrb Transcriptional responses of ren to physiological challenge support the presence of a functional renin-angiotensin system and are consistent with the production of active renin. The reparative capability of the zebrafish kidney was harnessed to demonstrate that ren transcription is a marker for renal injury and repair. Our studies demonstrate substantive conservation of renin regulation across vertebrates, and ultrastructural studies of renin cells reveal at least two distinct morphologies of mesonephric perivascular ren-expressing cells.
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Affiliation(s)
- Sebastien A Rider
- University/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, Little France, The University of Edinburgh, Edinburgh, United Kingdom;
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom; and
| | - Linda J Mullins
- University/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, Little France, The University of Edinburgh, Edinburgh, United Kingdom
| | - Amelia R Howarth
- University/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, Little France, The University of Edinburgh, Edinburgh, United Kingdom
| | - Calum A MacRae
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - John J Mullins
- University/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, Little France, The University of Edinburgh, Edinburgh, United Kingdom
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Lakhal-Littleton S, Wolna M, Chung YJ, Christian HC, Heather LC, Brescia M, Ball V, Diaz R, Santos A, Biggs D, Clarke K, Davies B, Robbins PA. An essential cell-autonomous role for hepcidin in cardiac iron homeostasis. eLife 2016; 5. [PMID: 27897970 PMCID: PMC5176354 DOI: 10.7554/elife.19804] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/24/2016] [Indexed: 12/16/2022] Open
Abstract
Hepcidin is the master regulator of systemic iron homeostasis. Derived primarily from the liver, it inhibits the iron exporter ferroportin in the gut and spleen, the sites of iron absorption and recycling respectively. Recently, we demonstrated that ferroportin is also found in cardiomyocytes, and that its cardiac-specific deletion leads to fatal cardiac iron overload. Hepcidin is also expressed in cardiomyocytes, where its function remains unknown. To define the function of cardiomyocyte hepcidin, we generated mice with cardiomyocyte-specific deletion of hepcidin, or knock-in of hepcidin-resistant ferroportin. We find that while both models maintain normal systemic iron homeostasis, they nonetheless develop fatal contractile and metabolic dysfunction as a consequence of cardiomyocyte iron deficiency. These findings are the first demonstration of a cell-autonomous role for hepcidin in iron homeostasis. They raise the possibility that such function may also be important in other tissues that express both hepcidin and ferroportin, such as the kidney and the brain. DOI:http://dx.doi.org/10.7554/eLife.19804.001 Many proteins inside cells require iron to work properly, and so this mineral is an essential part of the diets of most mammals. However, because too much iron in the body is also bad for health, mammals possess several proteins whose role is to maintain the balance of iron. Two proteins in particular, called hepcidin and ferroportin, are thought to be important in this process. Some ferroportin is found in the cells that line the gut (where iron is absorbed into the body) and is required to release this iron into the bloodstream. It is also found in the spleen, which is where iron is removed from old red blood cells so that it can be recycled. The liver produces hepcidin to control when ferroportin is active in the gut and spleen. Both hepcidin and ferroportin are also found in heart cells. In 2015, a study reported that that heart ferroportin plays an important role in heart activity. However, it was not clear what role hepcidin plays in this organ. Now, Lakhal-Littleton et al. – including many of the researchers from the previous work – have genetically engineered mice such that they specifically lacked heart hepcidin, or had a version of ferroportin in their heart that does not respond to hepcidin. The experiments show that these changes caused fatal heart failure in the mice because ferroportin releases iron from heart cells in an uncontrolled manner. Lakhal-Littleton et al. were able to prevent heart failure by injecting the animals with iron directly into the bloodstream. These findings show that hepcidin produced outside the liver has a role in controlling the levels of iron in the body’s organs. Other organs such as the brain, kidney and placenta all have their own forms of hepcidin and ferroportin; further work could investigate the roles of these proteins. Finally, another challenge for the future will be to test whether new drugs that are being developed to block or mimic hepcidin from the liver have the potential to treat heart conditions in humans. DOI:http://dx.doi.org/10.7554/eLife.19804.002
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Affiliation(s)
- Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Magda Wolna
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Yu Jin Chung
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Lisa C Heather
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Marcella Brescia
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Vicky Ball
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Rebeca Diaz
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Ana Santos
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Daniel Biggs
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Benjamin Davies
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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11
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Stefanska A, Kenyon C, Christian HC, Buckley C, Shaw I, Mullins JJ, Péault B. Human kidney pericytes produce renin. Kidney Int 2016; 90:1251-1261. [PMID: 27678158 PMCID: PMC5126097 DOI: 10.1016/j.kint.2016.07.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 12/20/2022]
Abstract
Pericytes, perivascular cells embedded in the microvascular wall, are crucial for vascular homeostasis. These cells also play diverse roles in tissue development and regeneration as multi-lineage progenitors, immunomodulatory cells and as sources of trophic factors. Here, we establish that pericytes are renin producing cells in the human kidney. Renin was localized by immunohistochemistry in CD146 and NG2 expressing pericytes, surrounding juxtaglomerular and afferent arterioles. Similar to pericytes from other organs, CD146+CD34–CD45–CD56– renal fetal pericytes, sorted by flow cytometry, exhibited tri-lineage mesodermal differentiation potential in vitro. Additionally, renin expression was triggered in cultured kidney pericytes by cyclic AMP as confirmed by immuno-electron microscopy, and secretion of enzymatically functional renin, capable of generating angiotensin I. Pericytes derived from second trimester human placenta also expressed renin in an inducible fashion although the renin activity was much lower than in renal pericytes. Thus, our results confirm and extend the recently discovered developmental plasticity of microvascular pericytes, and may open new perspectives to the therapeutic regulation of the renin-angiotensin system.
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Affiliation(s)
- Ania Stefanska
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - Christopher Kenyon
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Charlotte Buckley
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Isaac Shaw
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - John J Mullins
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Bruno Péault
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Scotland, UK; Orthopaedic Hospital Research Center, University of California, Los Angeles, California, USA.
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12
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Abstract
Thyrotrope hyperplasia and hypertrophy are common responses to primary hypothyroidism. To understand the genetic regulation of these processes, we studied gene expression changes in the pituitaries of Cga(-/-) mice, which are deficient in the common α-subunit of TSH, LH, and FSH. These mice have thyrotrope hypertrophy and hyperplasia and develop thyrotrope adenoma. We report that cell proliferation is increased, but the expression of most stem cell markers is unchanged. The α-subunit is required for secretion of the glycoprotein hormone β-subunits, and mutants exhibit elevated expression of many genes involved in the unfolded protein response, consistent with dilation and stress of the endoplasmic reticulum. Mutants have elevated expression of transcription factors that are important in thyrotrope function, such as Gata2 and Islet 1, and those that stimulate proliferation, including Nupr1, E2f1, and Etv5. We characterized the expression and function of a novel, overexpressed gene, transcription elongation factor A (SII)-like 5 (Tceal5). Stable expression of Tceal5 in a pituitary progenitor cell line is sufficient to increase cell proliferation. Thus, Tceal5 may act as a proto-oncogene. This study provides a rich resource for comparing pituitary transcriptomes and an analysis of gene expression networks.
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Affiliation(s)
- Peter Gergics
- Department of Human Genetics (P.G., M.S.C., S.A.C.), University of Michigan, Ann Arbor, Michigan 48109; Department of Physiology, Anatomy and Genetics (H.C.C.), University of Oxford, Oxford OX3 0RZ, United Kingdom; and Department of Internal Medicine, Metabolism, Endocrinology and Diabetes (A.A.), University of Michigan, Ann Arbor, Michigan 48105
| | - Helen C Christian
- Department of Human Genetics (P.G., M.S.C., S.A.C.), University of Michigan, Ann Arbor, Michigan 48109; Department of Physiology, Anatomy and Genetics (H.C.C.), University of Oxford, Oxford OX3 0RZ, United Kingdom; and Department of Internal Medicine, Metabolism, Endocrinology and Diabetes (A.A.), University of Michigan, Ann Arbor, Michigan 48105
| | - Monica S Choo
- Department of Human Genetics (P.G., M.S.C., S.A.C.), University of Michigan, Ann Arbor, Michigan 48109; Department of Physiology, Anatomy and Genetics (H.C.C.), University of Oxford, Oxford OX3 0RZ, United Kingdom; and Department of Internal Medicine, Metabolism, Endocrinology and Diabetes (A.A.), University of Michigan, Ann Arbor, Michigan 48105
| | - Adnan Ajmal
- Department of Human Genetics (P.G., M.S.C., S.A.C.), University of Michigan, Ann Arbor, Michigan 48109; Department of Physiology, Anatomy and Genetics (H.C.C.), University of Oxford, Oxford OX3 0RZ, United Kingdom; and Department of Internal Medicine, Metabolism, Endocrinology and Diabetes (A.A.), University of Michigan, Ann Arbor, Michigan 48105
| | - Sally A Camper
- Department of Human Genetics (P.G., M.S.C., S.A.C.), University of Michigan, Ann Arbor, Michigan 48109; Department of Physiology, Anatomy and Genetics (H.C.C.), University of Oxford, Oxford OX3 0RZ, United Kingdom; and Department of Internal Medicine, Metabolism, Endocrinology and Diabetes (A.A.), University of Michigan, Ann Arbor, Michigan 48105
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13
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Fernandes HJR, Hartfield EM, Christian HC, Emmanoulidou E, Zheng Y, Booth H, Bogetofte H, Lang C, Ryan BJ, Sardi SP, Badger J, Vowles J, Evetts S, Tofaris GK, Vekrellis K, Talbot K, Hu MT, James W, Cowley SA, Wade-Martins R. ER Stress and Autophagic Perturbations Lead to Elevated Extracellular α-Synuclein in GBA-N370S Parkinson's iPSC-Derived Dopamine Neurons. Stem Cell Reports 2016; 6:342-56. [PMID: 26905200 PMCID: PMC4788783 DOI: 10.1016/j.stemcr.2016.01.013] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 12/21/2022] Open
Abstract
Heterozygous mutations in the glucocerebrosidase gene (GBA) represent the strongest common genetic risk factor for Parkinson's disease (PD), the second most common neurodegenerative disorder. However, the molecular mechanisms underlying this association are still poorly understood. Here, we have analyzed ten independent induced pluripotent stem cell (iPSC) lines from three controls and three unrelated PD patients heterozygous for the GBA-N370S mutation, and identified relevant disease mechanisms. After differentiation into dopaminergic neurons, we observed misprocessing of mutant glucocerebrosidase protein in the ER, associated with activation of ER stress and abnormal cellular lipid profiles. Furthermore, we observed autophagic perturbations and an enlargement of the lysosomal compartment specifically in dopamine neurons. Finally, we found increased extracellular α-synuclein in patient-derived neuronal culture medium, which was not associated with exosomes. Overall, ER stress, autophagic/lysosomal perturbations, and elevated extracellular α-synuclein likely represent critical early cellular phenotypes of PD, which might offer multiple therapeutic targets.
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Affiliation(s)
- Hugo J R Fernandes
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Elizabeth M Hartfield
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Evangelia Emmanoulidou
- Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens, Athens 11526, Greece
| | - Ying Zheng
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Nuffield Department of Clinical Medicine, Division of Clinical Neurology, University of Oxford, Oxford OX3 9DU, UK
| | - Heather Booth
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Helle Bogetofte
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Institute of Molecular Medicine, University of Southern Denmark, Odense 5230, Denmark
| | - Charmaine Lang
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Brent J Ryan
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - S Pablo Sardi
- Genzyme, a Sanofi Company, Framingham, MA 01701, USA
| | - Jennifer Badger
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Jane Vowles
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; The James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Samuel Evetts
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Nuffield Department of Clinical Medicine, Division of Clinical Neurology, University of Oxford, Oxford OX3 9DU, UK
| | - George K Tofaris
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Nuffield Department of Clinical Medicine, Division of Clinical Neurology, University of Oxford, Oxford OX3 9DU, UK
| | - Kostas Vekrellis
- Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens, Athens 11526, Greece
| | - Kevin Talbot
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Nuffield Department of Clinical Medicine, Division of Clinical Neurology, University of Oxford, Oxford OX3 9DU, UK
| | - Michele T Hu
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Nuffield Department of Clinical Medicine, Division of Clinical Neurology, University of Oxford, Oxford OX3 9DU, UK
| | - William James
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; The James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Sally A Cowley
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; The James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
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14
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Featherstone K, Hey K, Momiji H, McNamara AV, Patist AL, Woodburn J, Spiller DG, Christian HC, McNeilly AS, Mullins JJ, Finkenstädt BF, Rand DA, White MRH, Davis JRE. Spatially coordinated dynamic gene transcription in living pituitary tissue. eLife 2016; 5:e08494. [PMID: 26828110 PMCID: PMC4749562 DOI: 10.7554/elife.08494] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 12/13/2015] [Indexed: 12/22/2022] Open
Abstract
Transcription at individual genes in single cells is often pulsatile and stochastic. A key question emerges regarding how this behaviour contributes to tissue phenotype, but it has been a challenge to quantitatively analyse this in living cells over time, as opposed to studying snap-shots of gene expression state. We have used imaging of reporter gene expression to track transcription in living pituitary tissue. We integrated live-cell imaging data with statistical modelling for quantitative real-time estimation of the timing of switching between transcriptional states across a whole tissue. Multiple levels of transcription rate were identified, indicating that gene expression is not a simple binary 'on-off' process. Immature tissue displayed shorter durations of high-expressing states than the adult. In adult pituitary tissue, direct cell contacts involving gap junctions allowed local spatial coordination of prolactin gene expression. Our findings identify how heterogeneous transcriptional dynamics of single cells may contribute to overall tissue behaviour.
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Affiliation(s)
- Karen Featherstone
- Centre for Endocrinology and Diabetes, University of Manchester, Manchester, United Kingdom
| | - Kirsty Hey
- Department of Statistics, University of Warwick, Coventry, United Kingdom
| | - Hiroshi Momiji
- Warwick Systems Biology, University of Warwick, Coventry, United Kingdom
| | - Anne V McNamara
- Systems Biology Centre, University of Manchester, Manchester, United Kingdom
| | - Amanda L Patist
- Centre for Endocrinology and Diabetes, University of Manchester, Manchester, United Kingdom
| | - Joanna Woodburn
- Centre for Endocrinology and Diabetes, University of Manchester, Manchester, United Kingdom
| | - David G Spiller
- Systems Biology Centre, University of Manchester, Manchester, United Kingdom
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Alan S McNeilly
- MRC Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - John J Mullins
- The Molecular Physiology Group, Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | | | - David A Rand
- Warwick Systems Biology, University of Warwick, Coventry, United Kingdom
| | - Michael RH White
- Systems Biology Centre, University of Manchester, Manchester, United Kingdom
| | - Julian RE Davis
- Centre for Endocrinology and Diabetes, University of Manchester, Manchester, United Kingdom
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15
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Wood SH, Christian HC, Miedzinska K, Saer BRC, Johnson M, Paton B, Yu L, McNeilly J, Davis JRE, McNeilly AS, Burt DW, Loudon ASI. Binary Switching of Calendar Cells in the Pituitary Defines the Phase of the Circannual Cycle in Mammals. Curr Biol 2015; 25:2651-62. [PMID: 26412130 PMCID: PMC4612467 DOI: 10.1016/j.cub.2015.09.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/11/2015] [Accepted: 09/04/2015] [Indexed: 12/21/2022]
Abstract
Persistent free-running circannual (approximately year-long) rhythms have evolved in animals to regulate hormone cycles, drive metabolic rhythms (including hibernation), and time annual reproduction. Recent studies have defined the photoperiodic input to this rhythm, wherein melatonin acts on thyrotroph cells of the pituitary pars tuberalis (PT), leading to seasonal changes in the control of thyroid hormone metabolism in the hypothalamus. However, seasonal rhythms persist in constant conditions in many species in the absence of a changing photoperiod signal, leading to the generation of circannual cycles. It is not known which cells, tissues, and pathways generate these remarkable long-term rhythmic processes. We show that individual PT thyrotrophs can be in one of two binary states reflecting either a long (EYA3(+)) or short (CHGA(+)) photoperiod, with the relative proportion in each state defining the phase of the circannual cycle. We also show that a morphogenic cycle driven by the PT leads to extensive re-modeling of the PT and hypothalamus over the circannual cycle. We propose that the PT may employ a recapitulated developmental pathway to drive changes in morphology of tissues and cells. Our data are consistent with the hypothesis that the circannual timer may reside within the PT thyrotroph and is encoded by a binary switch timing mechanism, which may regulate the generation of circannual neuroendocrine rhythms, leading to dynamic re-modeling of the hypothalamic interface. In summary, the PT-ventral hypothalamus now appears to be a prime structure involved in long-term rhythm generation.
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Affiliation(s)
- Shona H Wood
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Helen C Christian
- Department of Physiology, Anatomy, and Genetics, Le Gros Clark Building, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Katarzyna Miedzinska
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9PRG, UK
| | - Ben R C Saer
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Mark Johnson
- Department of Physiology, Anatomy, and Genetics, Le Gros Clark Building, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Bob Paton
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9PRG, UK
| | - Le Yu
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9PRG, UK
| | - Judith McNeilly
- MRC Centre for Reproductive Health, Queen's Medical Research Institute, Edinburgh EH16 4TJ, UK
| | - Julian R E Davis
- Faculty of Medical and Human Science, University of Manchester, Manchester, M13 9PT, UK
| | - Alan S McNeilly
- MRC Centre for Reproductive Health, Queen's Medical Research Institute, Edinburgh EH16 4TJ, UK
| | - David W Burt
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9PRG, UK.
| | - Andrew S I Loudon
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
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16
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Christensen AP, Patel SH, Grasa P, Christian HC, Williams SA. Oocyte glycoproteins regulate the form and function of the follicle basal lamina and theca cells. Dev Biol 2015; 401:287-98. [DOI: 10.1016/j.ydbio.2014.12.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 10/28/2014] [Accepted: 12/20/2014] [Indexed: 11/25/2022]
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17
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Christian HC, Imirtziadis L, Tortonese D. Ultrastructural changes in lactotrophs and folliculo-stellate cells in the ovine pituitary during the annual reproductive cycle. J Neuroendocrinol 2015; 27:277-84. [PMID: 25650820 DOI: 10.1111/jne.12261] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 01/30/2015] [Accepted: 01/30/2015] [Indexed: 11/26/2022]
Abstract
In seasonal mammals living in temperate zones, photoperiod regulates prolactin secretion, such that prolactin plasma concentrations peak during the summer months and are lowest during the winter. In sheep, a short-day breeder, circulating prolactin has important modulatory effects on the reproductive system via inhibitory actions on pituitary gonadotrophs and hypothalamic gonadotrophin-releasing hormone release. The exact cellular mechanisms that account for the chronic hypersecretion of prolactin during the summer is not known, although evidence supports an intrapituitary mechanism regulated by melatonin. Folliculo-stellate (FS) cells are non-endocrine cells that play a crucial role in paracrine communication within the pituitary and produce factors controlling prolactin and gonadotrophin release. The present study examined the morphology of the FS and lactotroph cell populations and their distribution in the sheep pituitary during the annual reproductive cycle. Ovine pituitary glands were collected in the winter (breeding season; BS) and summer (nonbreeding season; NBS) and were prepared for quantitative electron microscopy to assess the effects of season on FS and lactotroph cell density, morphology and distribution, as well as on junctional contacts between cells. It was found that lactotrophs in the NBS are larger in size and contain more numerous PRL granules than lactotrophs in the BS. FS cells were also larger in the NBS compared to BS and showed altered morphology such that, in the BS, long cell processes surrounded clusters of adjacent secretory cells. Although no significant change in the number of junctions was observed between lactotrophs and FS cells, or lactotrophs and gonadotrophs, there was a significant increase in the number of adherens junctions between lactotrophs and between FS cells. These findings demonstrate seasonal plasticity in the morphology of lactotrophs and FS cells that reflect changes in PRL secretion.
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Affiliation(s)
- H C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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18
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Lear PV, González-Touceda D, Porteiro Couto B, Viaño P, Guymer V, Remzova E, Tunn R, Chalasani A, García-Caballero T, Hargreaves IP, Tynan PW, Christian HC, Nogueiras R, Parrington J, Diéguez C. Absence of intracellular ion channels TPC1 and TPC2 leads to mature-onset obesity in male mice, due to impaired lipid availability for thermogenesis in brown adipose tissue. Endocrinology 2015; 156:975-86. [PMID: 25545384 PMCID: PMC4330317 DOI: 10.1210/en.2014-1766] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/23/2014] [Indexed: 12/11/2022]
Abstract
Intracellular calcium-permeable channels have been implicated in thermogenic function of murine brown and brite/beige adipocytes, respectively transient receptor potential melastin-8 and transient receptor potential vanilloid-4. Because the endo-lysosomal two-pore channels (TPCs) have also been ascribed with metabolic functionality, we studied the effect of simultaneously knocking out TPC1 and TPC2 on body composition and energy balance in male mice fed a chow diet. Compared with wild-type mice, TPC1 and TPC2 double knockout (Tpcn1/2(-/-)) animals had a higher respiratory quotient and became obese between 6 and 9 months of age. Although food intake was unaltered, interscapular brown adipose tissue (BAT) maximal temperature and lean-mass adjusted oxygen consumption were lower in Tpcn1/2(-/-) than in wild type mice. Phosphorylated hormone-sensitive lipase expression, lipid density and expression of β-adrenergic receptors were also lower in Tpcn1/2(-/-) BAT, whereas mitochondrial respiratory chain function and uncoupling protein-1 expression remained intact. We conclude that Tpcn1/2(-/-) mice show mature-onset obesity due to reduced lipid availability and use, and a defect in β-adrenergic receptor signaling, leading to impaired thermogenic activity, in BAT.
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Affiliation(s)
- Pamela V. Lear
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | | | | | - Patricia Viaño
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Vanessa Guymer
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Elena Remzova
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Ruth Tunn
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Annapurna Chalasani
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Tomás García-Caballero
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Iain P. Hargreaves
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Patricia W. Tynan
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Helen C. Christian
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
| | - Rubén Nogueiras
- Department of Physiology (P.V.L., D.G.-T., B.P.C., R.N., C.D.), Centre for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela and Institute of Health Sciences, and Department of Morphological Sciences (P.V., T.G.-C.), School of Medicine and University Clinical Hospital, University of Santiago de Compostela, Santiago de Compostela 15782, Spain; Department of Pharmacology (P.V.L., R.T., P.W.T., J.P.), Oxford University, Oxford OX1 3QT, United Kingdom; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (D.G.-T., B.P.C., R.N., C.D.), 15706, Santiago de Compostela, Spain; Department of Physiology, Anatomy, and Genetics (V.G., H.C.C.), Oxford University, Oxford OX1 3QX, United Kingdom; and Neurometabolic Unit (E.R., A.C., I.P.H.), National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London WC1N 3BG, United Kingdom
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19
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Budzik J, Omer S, Morris JF, Christian HC. Vascular endothelial growth factor secretion from pituitary folliculostellate cells: role of KATP channels. J Neuroendocrinol 2014; 26:111-20. [PMID: 24176035 DOI: 10.1111/jne.12117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/02/2013] [Accepted: 10/28/2013] [Indexed: 01/08/2023]
Abstract
Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen responsible for physiological and pathological angiogenesis. Abnormal regulation of VEGF expression in anterior pituitary folliculostellate (FS) cells has been implicated in pituitary tumour progression. FS and endocrine cells express VEGF, which is considered to be secreted by the constitutive pathway. The present study investigated the mechanism of VEGF secretion in TtT/GF cells, a mouse FS cell line. TtT/GF cells were shown to express VEGF(164), the most potent and bioavailable isoform of VEGF. Immunofluorescence and immunogold electron microscopy localised VEGF to the cytoplasm and small electron-lucent vesicles. Pituitary adenylate cyclase-activating polypeptide (PACAP), a well-documented stimulant of VEGF secretion, caused a robust increase in VEGF secretion over 24 h. Glyburide, an ABCA1 and K(ATP) channel blocker, also caused an increase in VEGF secretion when applied alone, and amplified the response to PACAP. Other ABCA1 transport blockers did not affect VEGF secretion. Exposure of TtT/GF cells to cycloheximide with PACAP or glyburide inhibited the increased secretion of VEGF, consistent with control of secretion at the transcription level. The SUR2B/Kir6.1 form of K(ATP) channels was shown to be expressed by TtT/GF cells. Diazoxide, a K(ATP) activator, inhibited PACAP- and PACAP + glyburide-stimulated VEGF secretion but not that of glyburide alone. These data suggest that K(ATP) channels are expressed by FS cells and play a significant role in the control of VEGF secretion, and also that activation of K(ATP) channels inhibits the secretion of VEGF at the level of transcription.
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Affiliation(s)
- J Budzik
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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20
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Slingo ME, Turner PJ, Christian HC, Buckler KJ, Robbins PA. The von Hippel-Lindau Chuvash mutation in mice causes carotid-body hyperplasia and enhanced ventilatory sensitivity to hypoxia. J Appl Physiol (1985) 2013; 116:885-92. [PMID: 24030664 PMCID: PMC3972741 DOI: 10.1152/japplphysiol.00530.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The hypoxia-inducible factor (HIF) family of transcription factors coordinates diverse cellular and systemic responses to hypoxia. Chuvash polycythemia (CP) is an autosomal recessive disorder in humans in which there is impaired oxygen-dependent degradation of HIF, resulting in long-term systemic elevation of HIF levels at normal oxygen tensions. CP patients demonstrate the characteristic features of ventilatory acclimatization to hypoxia, namely, an elevated baseline ventilation and enhanced acute hypoxic ventilatory response (AHVR). We investigated the ventilatory and carotid-body phenotype of a mouse model of CP, using whole-body plethysmography, immunohistochemistry, and electron microscopy. In keeping with studies in humans, CP mice had elevated ventilation in euoxia and a significantly exaggerated AHVR when exposed to 10% oxygen, with or without the addition of 3% carbon dioxide. Carotid-body immunohistochemistry demonstrated marked hyperplasia of the oxygen-sensing type I cells, and the cells themselves appeared enlarged with more prominent nuclei. This hypertrophy was confirmed by electron microscopy, which also revealed that the type I cells contained an increased number of mitochondria, enlarged dense-cored vesicles, and markedly expanded rough endoplasmic reticulum. The morphological and ultrastructural changes seen in the CP mouse carotid body are strikingly similar to those observed in animals exposed to chronic hypoxia. Our study demonstrates that the HIF pathway plays a major role, not only in regulating both euoxic ventilatory control and the sensitivity of the response to hypoxia, but also in determining the morphology of the carotid body.
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Affiliation(s)
- Mary E Slingo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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21
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Williams JP, Southern P, Lissina A, Christian HC, Sewell AK, Phillips R, Pankhurst Q, Frater J. Application of magnetic field hyperthermia and superparamagnetic iron oxide nanoparticles to HIV-1-specific T-cell cytotoxicity. Int J Nanomedicine 2013; 8:2543-54. [PMID: 23901272 PMCID: PMC3726440 DOI: 10.2147/ijn.s44013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The latent HIV-1 reservoir remains the major barrier to HIV-1 eradication. Although successful at limiting HIV replication, highly active antiretroviral therapy is unable to cure HIV infection, thus novel therapeutic strategies are needed to eliminate the virus. Magnetic field hyperthermia (MFH) generates thermoablative cytotoxic temperatures in target-cell populations, and has delivered promising outcomes in animal models, as well as in several cancer clinical trials. MFH has been proposed as a strategy to improve the killing of HIV-infected cells and for targeting the HIV latent reservoirs. We wished to determine whether MFH could be used to enhance cytotoxic T-lymphocyte (CTL) targeting of HIV-infected cells in a proof-of-concept study. Here, for the first time, we apply MFH to an infectious disease (HIV-1) using the superparamagnetic iron oxide nanoparticle FeraSpin R. We attempt to improve the cytotoxic potential of T-cell receptor-transfected HIV-specific CTLs using thermotherapy, and assess superparamagnetic iron oxide nanoparticle toxicity, uptake, and effect on cell function using more sensitive methods than previously described. FeraSpin R exhibited only limited toxicity, demonstrated efficient uptake and cell-surface attachment, and only modestly impacted T-cell function. In contrast to the cancer models, insufficient MFH was generated to enhance CTL killing of HIV-infected cells. MFH remains an exciting new technology in the field of cancer therapeutics, which, as technology improves, may have significant potential to enhance CTL function and act as an adjunctive therapy in the eradication of latently infected HIV-positive cells.
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Affiliation(s)
- James P Williams
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, UK
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22
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Pieri M, Christian HC, Wilkins RJ, Boyd CAR, Meredith D. The apical (hPepT1) and basolateral peptide transport systems of Caco-2 cells are regulated by AMP-activated protein kinase. Am J Physiol Gastrointest Liver Physiol 2010; 299:G136-43. [PMID: 20430871 PMCID: PMC2904111 DOI: 10.1152/ajpgi.00014.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effect of 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) activation of the AMP-activated protein kinase (AMPK) on the transport of the model radiolabeled dipeptide [(3)H]-D-Phe-L-Gln was investigated in the human epithelial colon cancer cell line Caco-2. Uptake and transepithelial fluxes of [(3)H]-D-Phe-L-Gln were carried out in differentiated Caco-2 cell monolayers, and hPepT1 and glucose transporter 2 (GLUT2) protein levels were quantified by immunogold electron microscopy. AICAR treatment of Caco-2 cells significantly inhibited apical [(3)H]-D-Phe-L-Gln uptake, matched by a decrease in brush-border membrane hPepT1 protein but with a concomitant increase in the facilitated glucose transporter GLUT2. A restructuring of the apical brush-border membrane was seen by electron microscopy. The hPepT1-mediated transepithelial (A-to-B) peptide flux across the Caco-2 monolayers showed no significant alteration in AICAR-treated cells. The electrical resistance in the AICAR-treated monolayers was significantly higher compared with control cells. Inhibition of the sodium/hydrogen exchanger 3 (NHE3) had an additive effect to AICAR, suggesting that the AMPK effect is not via NHE3. Fluorescence measurement of intracellular pH showed no reduction in the proton gradient driving PepT1-mediated apical uptake. The reduction in apical hPepT1 protein and dipeptide uptake after AICAR treatment in Caco-2 cells demonstrates a regulatory effect of AMPK on hPepT1, along with an influence on both the microvilli and tight junction structures. The absence of an associated reduction in transepithelial peptide movement implies an additional stimulatory effect of AICAR on the basolateral peptide transport system in these cells. These results provide a link between the hPepT1 transporter and the metabolic state of this model enterocyte.
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Affiliation(s)
- Myrtani Pieri
- 1School of Life Sciences, Oxford Brookes University, Headington, Oxford; ,2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Helen C. Christian
- 2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Robert J. Wilkins
- 2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - C. A. R. Boyd
- 2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - David Meredith
- 1School of Life Sciences, Oxford Brookes University, Headington, Oxford; ,2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Fountaine TM, Venda LL, Warrick N, Christian HC, Brundin P, Channon KM, Wade-Martins R. The effect of alpha-synuclein knockdown on MPP+ toxicity in models of human neurons. Eur J Neurosci 2008; 28:2459-73. [PMID: 19032594 DOI: 10.1111/j.1460-9568.2008.06527.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The protein alpha-synuclein is central to the pathophysiology of Parkinson's disease (PD) but its role in the development of neurodegeneration remains unclear. alpha-Synuclein-knockout mice develop without gross abnormality and are resistant to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial inhibitor widely used to model parkinsonism. Here we show that differentiated human dopaminergic neuron-like cells also have increased resistance to 1-methyl-4-phenylpyridine (MPP+), the active metabolite of MPTP, when alpha-synuclein is knocked down using RNA interference. In attempting to understand how this occurred we found that lowering alpha-synuclein levels caused changes to intracellular vesicles, dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2), each of which is known to be an important component of the early events leading to MPP+ toxicity. Knockdown of alpha-synuclein reduced the availability of DAT on the neuronal surface by 50%, decreased the total number of intracellular vesicles by 37% but increased the density of VMAT2 molecules per vesicle by 2.8-fold. However, these changes were not associated with any reduction in MPP+ -induced superoxide production, suggesting that alpha-synuclein knockdown may have other downstream effects which are important. We then showed that alpha-synuclein knockdown prevented MPP+ -induced activation of nitric oxide synthase (NOS). Activation of NOS is an essential step in MPTP toxicity and increasing evidence points to nitrosative stress as being important in neurodegeneration. Overall, these results show that as well as having a number of effects on cellular events upstream of mitochondrial dysfunction alpha-synuclein affects pathways downstream of superoxide production, possibly involving regulation of NOS activity.
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Affiliation(s)
- Timothy M Fountaine
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
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24
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Abstract
1. The monocarboxylate transporter (MCT, SLC16) family comprises 14 members, of which to date only MCT1-4 have been shown to carry monocarboxylates, transporting important metabolic compounds such as lactate, pyruvate and ketone bodies in a proton-coupled manner. The transport of such compounds is fundamental for metabolism, and the tissue locations, properties and regulation of these isoforms is discussed. 2. Of the other members of the MCT family, MCT8 (a thyroid hormone transporter) and TAT1 (an aromatic amino acid transporter) have been characterized more recently, and their physiological roles are reviewed herein. The endogenous substrates and functions of the remaining members of the MCT family await elucidation. 3. The MCT proteins have the typical twelve transmembrane-spanning domain (TMD) topology of membrane transporter proteins, and their structure-function relationship is discussed, especially in relation to the future impact of the single nucleotide polymorphism (SNP) databases and, given their ability to transport pharmacologically relevant compounds, the potential impact for pharmacogenomics.
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Affiliation(s)
- D Meredith
- School of Life Sciences, Oxford Brookes University, Headington, Oxford, UK.
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25
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Leontiou CA, Gueorguiev M, van der Spuy J, Quinton R, Lolli F, Hassan S, Chahal HS, Igreja SC, Jordan S, Rowe J, Stolbrink M, Christian HC, Wray J, Bishop-Bailey D, Berney DM, Wass JAH, Popovic V, Ribeiro-Oliveira A, Gadelha MR, Monson JP, Akker SA, Davis JRE, Clayton RN, Yoshimoto K, Iwata T, Matsuno A, Eguchi K, Musat M, Flanagan D, Peters G, Bolger GB, Chapple JP, Frohman LA, Grossman AB, Korbonits M. The role of the aryl hydrocarbon receptor-interacting protein gene in familial and sporadic pituitary adenomas. J Clin Endocrinol Metab 2008; 93:2390-401. [PMID: 18381572 DOI: 10.1210/jc.2007-2611] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
CONTEXT Mutations have been identified in the aryl hydrocarbon receptor-interacting protein (AIP) gene in familial isolated pituitary adenomas (FIPA). It is not clear, however, how this molecular chaperone is involved in tumorigenesis. OBJECTIVE AIP sequence changes and expression were studied in FIPA and sporadic adenomas. The function of normal and mutated AIP molecules was studied on cell proliferation and protein-protein interaction. Cellular and ultrastructural AIP localization was determined in pituitary cells. PATIENTS Twenty-six FIPA kindreds and 85 sporadic pituitary adenoma patients were included in the study. RESULTS Nine families harbored AIP mutations. Overexpression of wild-type AIP in TIG3 and HEK293 human fibroblast and GH3 pituitary cell lines dramatically reduced cell proliferation, whereas mutant AIP lost this ability. All the mutations led to a disruption of the protein-protein interaction between AIP and phosphodiesterase-4A5. In normal pituitary, AIP colocalizes exclusively with GH and prolactin, and it is found in association with the secretory vesicle, as shown by double-immunofluorescence and electron microscopy staining. In sporadic pituitary adenomas, however, AIP is expressed in all tumor types. In addition, whereas AIP is expressed in the secretory vesicle in GH-secreting tumors, similar to normal GH-secreting cells, in lactotroph, corticotroph, and nonfunctioning adenomas, it is localized to the cytoplasm and not in the secretory vesicles. CONCLUSIONS Our functional evaluation of AIP mutations is consistent with a tumor-suppressor role for AIP and its involvement in familial acromegaly. The abnormal expression and subcellular localization of AIP in sporadic pituitary adenomas indicate deranged regulation of this protein during tumorigenesis.
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Affiliation(s)
- Chrysanthia A Leontiou
- Department of Endocrinology, Barts and the London School of Medicine, London, United Kingdom
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El-Kasti MM, Christian HC, Huerta-Ocampo I, Stolbrink M, Gill S, Houston PA, Davies JS, Chilcott J, Hill N, Matthews DR, Carter DA, Wells T. The pregnancy-induced increase in baseline circulating growth hormone in rats is not induced by ghrelin. J Neuroendocrinol 2008; 20:309-22. [PMID: 18208550 DOI: 10.1111/j.1365-2826.2008.01650.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The elevation in baseline circulating growth hormone (GH) that occurs in pregnant rats is thought to arise from increased pituitary GH secretion, but the underlying mechanism remains unclear. Distribution, Fourier and algorithmic analyses confirmed that the pregnancy-induced increase in circulating GH in 3-week pregnant rats was due to a 13-fold increase in baseline circulating GH (P < 0.01), without any significant alteration in the parameters of episodic secretion. Electron microscopy revealed that pregnancy resulted in a reduction in the proportion of mammosomatotrophs (P < 0.01) and an increase in type II lactotrophs (P < 0.05), without any significant change in the somatotroph population. However, the density of the secretory granules in somatotrophs from 3-week pregnant rats was reduced (P < 0.05), and their distribution markedly polarised; the granules being grouped nearest the vasculature. Pituitary GH content was not increased, but steady-state GH mRNA levels declined progressively during pregnancy (P < 0.05). In situ hybridisation revealed that pregnancy was accompanied by a suppression of GH-releasing hormone mRNA expression in the arcuate nuclei (P < 0.05) and enhanced somatostatin mRNA expression in the periventricular nuclei (P < 0.05), an expression pattern normally associated with increased GH feedback. Although gastric ghrelin mRNA expression was elevated by 50% in 3-week pregnant rats (P < 0.01), circulating ghrelin, GH-secretagogue receptor mRNA expression and the GH response to a bolus i.v. injection of exogenous ghrelin were all largely unaffected during pregnancy. Although trace amounts of 'pituitary' GH could be detected in the placenta with radioimmunoassay, significant GH-immunoreactivity could not be observed by immunohistochemistry, indicating that rat placenta itself does not produce 'pituitary' GH. Although not excluding the possibility that the pregnancy-associated elevation in baseline circulating GH could arise from alternative extra-pituitary sources (e.g. the ovary), our data indicate that this phenomenon is most likely to result from a direct alteration of somatotroph function.
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Affiliation(s)
- M M El-Kasti
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
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Abstract
Androgens are known to exert their effects via genomic signalling, which involves intracellular androgen receptors that modulate gene expression on steroid binding. Whereas non-classical estrogen effects are well established, it is only recently that non-classical, rapid, membrane-initiated testosterone actions have received attention. Non-classical effects of testosterone have now been demonstrated convincingly in several tissues, in particular in the reproductive, cardiovascular, immune and musculoskeletal systems. There is evidence for the participation of the classical intracellular androgen receptor and for involvement of novel, membrane-associated androgen receptors in the non-classical actions of testosterone. Here we discuss evidence for rapid testosterone actions, which have clinical implications in fertility, cardiovascular disease and the treatment of prostate cancer.
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Affiliation(s)
- Faisal Rahman
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
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Christian HC, Chapman LP, Morris JF. Thyrotrophin-releasing hormone, vasoactive intestinal peptide, prolactin-releasing peptide and dopamine regulation of prolactin secretion by different lactotroph morphological subtypes in the rat. J Neuroendocrinol 2007; 19:605-13. [PMID: 17620102 DOI: 10.1111/j.1365-2826.2007.01567.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In the male rat anterior pituitary, three morphological subtypes of cells secreting primarily prolactin (PRL) (lactotrophs) have been described. Type I contain predominantly large irregularly shaped granules, whereas type II and type III lactotrophs contain smaller spherical granules. We have previously shown that oestradiol and testosterone exert a rapid stimulatory effect selectively on type II lactotrophs but it is not known how the lactotroph subtypes respond to peptide secretagogues. We have therefore examined which cell subtype(s) release PRL in response to vasoactive intestinal peptide (VIP), thyrotrophin-releasing hormone (TRH) and prolactin-releasing peptide (PrRP-31). Pituitary segments were incubated in medium containing tannic acid (to capture exocytosis of secretory granules), either alone or with secretagogue peptide. VIP (1-10 nM), TRH (10 nM) and PrRP-31 (10 nM) all caused a significant increase (P < 0.05) in the amount of PRL granule exocytosis from type II and III lactotrophs, but had no effect on PRL exocytosis from type I. Dopamine (100 nM) inhibited basal exocytosis of immunoreactive (ir)-PRL from type I, II and III lactotrophs and PrRP-31-stimulated ir-PRL granule exocytosis from II and III lactotrophs. Treatment of lactating female rats with the dopamine D(2) receptor antagonist sulpiride (40 microg/kg) produced a significant increase (P < 0.05) in PRL granule exocytosis from type I and type III lactotrophs and a significant increase (P < 0.05) in the proportion of type I and II cells undergoing exocytosis of PRL. In conclusion, VIP, TRH and PrRP-31 selectively stimulate exocytosis from type II and III lactotrophs in the male rat, whereas all three lactotroph types are sensitive to dopamine inhibition of exocytosis in male and female rats.
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Affiliation(s)
- H C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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29
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Dalton P, Christian HC, Redman CWG, Sargent IL, Boyd CAR. Membrane trafficking of CD98 and its ligand galectin 3 in BeWo cells − implication for placental cell fusion. FEBS J 2007; 274:2715-27. [PMID: 17451431 DOI: 10.1111/j.1742-4658.2007.05806.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
CD98 heavy chain (CD98hc), expressed at high levels in developing human trophoblasts, is an integral membrane protein with multiple N-linked glycosylation sites and known to be important for cell fusion, adhesion, and amino acid transport. Western blotting and flow cytometry were used to study the effect of brefeldin A, an inhibitor of protein translocation through the Golgi, on CD98hc in the human placental trophoblast cell line BeWo. Although brefeldin A treatment caused increased cell surface expression of CD98hc, a novel partially glycosylated form of the protein was found and, concomitantly, cell fusion was reduced. Western blotting showed that CD98 and galectin 3, a proposed ligand for the glycosylated extracellular domain of CD98hc, co-immunoprecipitated, and double-label immuno-electron microscopy confirmed that CD98hc associated with galectin 3. Furthermore, cell fusion was reduced (specifically) by the disaccharide lactose, a known ligand for the carbohydrate recognition domain of galectin 3, suggesting that the association was functional. Taken together, the data suggest that N-glycosylation of CD98 and subsequent interaction with galectin 3 is critical for aspects of placental cell biology, and provides a rationale for the observation that, in the mouse, truncation of the CD98hc extracellular domain leads to early embryonic lethality [Tsumura H, Suzuki N, Saito H, Kawano M, Otake S, Kozuka Y, Komada H, Tsurudome M & Ito Y (2003) Biochem Biophys Res Commun 308, 847-851].
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Affiliation(s)
- Paola Dalton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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30
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Davies E, Omer S, Buckingham JC, Morris JF, Christian HC. Expression and externalization of annexin 1 in the adrenal gland: structure and function of the adrenal gland in annexin 1-null mutant mice. Endocrinology 2007; 148:1030-8. [PMID: 17158208 DOI: 10.1210/en.2006-0732] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Annexin 1 (ANXA1) is a member of the annexin family of phospholipid- and calcium-binding proteins with a well demonstrated role in early delayed (30 min to 3 h) inhibitory feedback of glucocorticoids in the hypothalamus and pituitary gland. This study used adrenal gland tissue from ANXA1-null transgenic mice, in which a beta-galactosidase (beta-Gal) reporter gene was controlled by the ANXA1 promoter, and wild-type control mice to explore the potential role of ANXA1 in adrenal function. RT-PCR and Western blotting revealed strong expression of ANXA1 mRNA and protein in the adrenal gland. Immunofluorescence labeling of ANXA1 in wild-type and beta-Gal expression in ANXA1-null adrenals localized intense staining in the outer perimeter cell layers. Immunogold electron microscopy identified cytoplasmic and nuclear ANXA1 labeling in outer cortical cells and capsular cells. Exposure of adrenal segments in vitro to dexamethasone (0.1 mum, 3 h) caused an increase in the amount of ANXA1 in the intracellular compartment and attached to the surface of the cells. The N-terminal peptide ANXA1(Ac2-26) inhibited corticosterone release. Corticosterone release was significantly greater from ANXA1-null adrenal cells compared with wild type in response to ACTH (10 pm to 5 nm). In contrast, basal and ACTH-stimulated aldosterone release from ANXA1-null adrenal cells was not different from wild type. Morphometry studies demonstrated that ANXA1 null adrenal glands were smaller than wild-type, and the cortical/medullary area ratio was significantly reduced. These results suggest ANXA1 is a regulator of adrenocortical size and corticosterone secretion.
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Affiliation(s)
- Evelyn Davies
- Department of Physiology, Anatomy, and Genetics, University of Oxford, South Parks Road, Oxford, United Kingdom
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31
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Dalton P, Christian HC, Redman CWG, Sargent IL, Boyd CAR. Differential effect of cross-linking the CD98 heavy chain on fusion and amino acid transport in the human placental trophoblast (BeWo) cell line. Biochimica et Biophysica Acta (BBA) - Biomembranes 2007; 1768:401-10. [PMID: 17258169 DOI: 10.1016/j.bbamem.2006.11.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 11/02/2006] [Accepted: 11/27/2006] [Indexed: 12/17/2022]
Abstract
CD98 (otherwise known as 4F2) is an integral membrane protein with multiple functions including amino acid transport, integrin activation, cell fusion and cell activation. The molecular mechanisms coordinating these multiple functions remain unclear. We have studied CD98 heavy chain (hc) function in a human placental trophoblast cell line (BeWo). We show that cross-linking of CD98hc by incubation of cells in the presence of functional monoclonal antibodies causes cellular re-distribution of the protein from the cytoplasm to the plasma membrane as measured by flow cytometry, western blotting and quantitative immuno-electron microscopy. The latter technique also indicated that CD98hc is trafficked between cell surface and cytoplasmic pools in vesicles. Increased cell surface CD98 correlates with increased cellular fusion in BeWo cells. In addition, we show reduced LAT 1 surface expression and neutral amino acid transport in the presence of the CD98 mabs. The results thus suggest that the function of CD98 in cell fusion is distinct from its role in cellular nutrient delivery.
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Affiliation(s)
- Paola Dalton
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
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Davies E, Omer S, Morris JF, Christian HC. The influence of 17beta-estradiol on annexin 1 expression in the anterior pituitary of the female rat and in a folliculo-stellate cell line. J Endocrinol 2007; 192:429-42. [PMID: 17283243 PMCID: PMC1994562 DOI: 10.1677/joe-06-0132] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Annexin 1 (ANXA1) is a Ca2+- and phospholipid-binding protein that plays an important role as a mediator of glucocorticoid action in the host-defence and neuroendocrine systems. Sex differences in hypothalamo-pituitary-adrenal (HPA) axis activity are well documented and a number of studies have demonstrated that gonadal steroids act as regulators of HPA activity. The aim of this study was to investigate the effect of ovariectomy and 17beta-estradiol replacement, and estrous cycle stage, on anterior pituitary ANXA1 content. The amount of anterior pituitary ANXA1 determined by western blotting varied with estrous cycle stage with a peak at estrus declining to a trough at proestrus. Ovariectomy resulted in a significant (P<0 x 05) decrease in anterior pituitary ANXA1 content. Administration of 17beta-estradiol (1 microg/100 g) significantly (P<0 x 01) increased anterior pituitary ANXA1 expression in the ovariectomized animals. In contrast, there was no change in pituitary ANXA1 content in response to 17beta-estradiol in adrenalectomized and adrenalectomized/ovariectomized rats. Treatment of TtT/GF cells, a folliculo-stellate cell line, with 17beta-estradiol (1 x 8-180 nM) increased ANXA1 mRNA expression and increased the amount of ANXA1 protein externalized in response to a dexamethasone stimulus. These results indicate that 17beta-estradiol stimulates ANXA1 expression in the anterior pituitary and in vivo an adrenal factor contributes to the mechanism of action.
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33
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Silistino-Souza R, Rodrigues-Lisoni FC, Cury PM, Maniglia JV, Raposo LS, Tajara EH, Christian HC, Oliani SM. Annexin 1: Differential expression in tumor and mast cells in human larynx cancer. Int J Cancer 2007; 120:2582-9. [PMID: 17340616 DOI: 10.1002/ijc.22639] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Annexin 1 protein (ANXA1) expression was evaluated in tumor and mast cells in human larynx cancer and control epithelium. The effect of the exogenous ANXA1 (peptide Ac 2-26) was also examined during the cellular growth of the Hep-2 human larynx epidermoid carcinoma cell line. This peptide inhibited the proliferation of the Hep-2 cells within 144 hr. In surgical tissue specimens from 20 patients with larynx cancer, ultrastructural immunocytochemistry analysis showed in vivo down-regulation of ANXA1 expression in the tumor and increased in mast cells and Hep-2 cells treated with peptide Ac2-26. Combined in vivo and in vitro analysis demonstrated that ANXA1 plays a regulatory role in laryngeal cancer cell growth. We believe that a better understanding of the regulatory mechanisms of ANXA1 in tumor and mast cells may lead to future biological targets for the therapeutic intervention of human larynx cancer.
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Affiliation(s)
- Rosana Silistino-Souza
- Department of Biology, Instituto de Biociências, Letras e Ciências Exatas (IBILCE), São Paulo State University (UNESP), São José do Rio Preto, São Paulo, Brazil
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John CD, Theogaraj E, Christian HC, Morris JF, Smith SF, Buckingham JC. Time-specific effects of perinatal glucocorticoid treatment on anterior pituitary morphology, annexin 1 expression and adrenocorticotrophic hormone secretion in the adult female rat. J Neuroendocrinol 2006; 18:949-59. [PMID: 17076770 DOI: 10.1111/j.1365-2826.2006.01493.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Perinatal glucocorticoid (GC) treatment is increasingly associated with long-term disturbances in hypothalamo-pituitary-adrenocortical function. In the male rat, such treatment induces profound molecular, morphological and functional changes in the anterior pituitary gland at adulthood. To determine whether these effects are sex-specific, we have examined the effects of perinatal dexamethasone treatment on the female pituitary gland, focusing on (i) the integrity of the annexin 1 (ANXA1) dependent regulatory effects of GCs on adrenocorticotrophic hormone (ACTH) release and (ii) corticotroph and folliculo-stellate (FS) cell morphology. Dexamethasone was given to pregnant (gestational days 16-19) or lactating (days 1-7 post partum) rats via the drinking water (1 microg/ml); controls received normal drinking water. Pituitary tissue from the female offspring was examined ex vivo at adulthood (60-90 days). Both treatment regimes reduced the intracellular and cell surface ANXA1 expression, as determined by western blot analysis and quantitative immunogold electron microscopic histochemistry. In addition, they compromised the ability of dexamethasone to suppress the evoked release of ACTH from the excised tissue in vitro, a process which requires the translocation of ANXA1 from the cytoplasm to the cell surface of FS cells. Although neither treatment regime affected the number of FS cells or corticotrophs, both altered the subcellular morphology of these cells. Thus, prenatal dexamethasone treatment increased while neonatal treatment decreased FS cell size and cytoplasmic area. By contrast, corticotroph size was unaffected by either treatment, as also was the size of the secretory granules. Corticotroph granule density and margination were, however, increased markedly by the prenatal treatment, while the neonatal treatment had no effect on granule density but decreased granule margination. Thus, perinatal dexamethasone treatment exerts long-term effects on the female pituitary gland, altering gene expression, cell morphology and the ANXA1-dependent GC regulation of ACTH secretion. The changes are similar but not identical to those reported in the male.
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Affiliation(s)
- C D John
- Department of Cellular and Molecular Neuroscience, Division of Neuroscience and Mental Health, Imperial College London, Hammersmith Campus, London, UK
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Warne JP, John CD, Christian HC, Morris JF, Flower RJ, Sugden D, Solito E, Gillies GE, Buckingham JC. Gene deletion reveals roles for annexin A1 in the regulation of lipolysis and IL-6 release in epididymal adipose tissue. Am J Physiol Endocrinol Metab 2006; 291:E1264-73. [PMID: 16835395 PMCID: PMC1855443 DOI: 10.1152/ajpendo.00655.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this study, epididymal adipose tissue from male annexin 1 (ANXA1)-null and wild-type control mice were used to explore the potential role of ANXA1 in adipocyte biology. ANXA1 was detected by Western blot analysis in wild-type tissue and localized predominantly to the stromal-vascular compartment. Epididymal fat pad mass was reduced by ANXA1 gene deletion, but adipocyte size was unchanged, suggesting that ANXA1 is required for the maintenance of adipocyte and/or preadipocyte cell number. Epididymal tissue from wild-type mice responded in vitro to noradrenaline and isoprenaline with increased glycerol release, reduced IL-6 release, and increased cAMP accumulation. Qualitatively similar but significantly attenuated responses to the catecholamines were observed in tissue from ANXA1-null mice, an effect that was not associated with changes in beta-adrenoceptor mRNA expression. Lipopolysaccharide (LPS) also stimulated lipolysis in vitro, but its effects were muted by ANXA1 gene deletion. By contrast, LPS failed to influence IL-6 release from wild-type tissue but stimulated the release of the cytokine from tissue from ANXA1-null mice. ANXA1 gene deletion did not affect glucocorticoid receptor expression or the ability of dexamethasone to suppress catecholamine-induced lipolysis. It did, however, augment IL-6 expression and modify the inhibitory effects of glucocorticoids on IL-6 release. Collectively, these studies suggest that ANXA1 supports aspects of adipose tissue mass and alters the sensitivity of epididymal adipose tissue to catecholamines, glucocorticoids, and LPS, thereby modulating lipolysis and IL-6 release.
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Affiliation(s)
- James P Warne
- Dept. of Cellular and Molecular Neuroscience, Division of Neuroscience and Mental Health, Imperial College London, Hammersmith Campus, London, W12 0NN, UK
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Morris JF, Omer S, Davies E, Wang E, John C, Afzal T, Wain S, Buckingham JC, Flower RJ, Christian HC. Lack of annexin 1 results in an increase in corticotroph number in male but not female mice. J Neuroendocrinol 2006; 18:835-46. [PMID: 17026533 PMCID: PMC1855440 DOI: 10.1111/j.1365-2826.2006.01481.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Annexin 1 (ANXA1) is a member of the annexin family of phospholipid- and calcium-binding proteins with a well demonstrated role in early delayed (30 min to 3 h) inhibitory feedback of glucocorticoids in the pituitary. We have examined corticotrophs in wild-type and ANXA1 knockout mice to determine the effects of lack of ANXA1 in male and female animals. Anterior pituitary tissue from ANXA1 wild-type, heterozygote and null mice was fixed and examined (i) by confocal immunocytochemistry to determine the number of corticotrophs and (ii) by electron microscopy to examine the size, secretory granule population and secretory machinery of corticotrophs. No differences in these parameters were detected in female mice. In male ANXA1 null mice, there were approximately four-fold more corticotrophs than in wild-type animals. However, the corticotrophs in ANXA1 null mice were smaller and had reduced numbers of secretory granules (the reduction in granules paralleled the reduction in cell size). No differences in the numerical density of folliculo-stellate, gonadotroph, lactotroph or somatotroph cells were detected in male ANXA1 null mice. Plasma corticosterone, adrenocorticotrophic hormone (ACTH) and pituitary pro-opiomelanocortin mRNA were unchanged but pituitary ACTH content was increased in male ANXA1 null mice. Interleukin (IL)-6 pituitary content was significantly elevated in male and reduced in female ANXA1 null mice compared to wild-type. In conclusion, these data indicate that ANXA1 deficiency is associated with gender-specific changes in corticotroph number and structure, via direct actions of ANXA1 and/or indirect changes in factors such as IL-6.
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Affiliation(s)
- J F Morris
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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37
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Davies JS, Thompson NM, Christian HC, Pinilla L, Ebling FJP, Tena-Sempere M, Wells T. Hypothalamic expression of human growth hormone induces post-pubertal hypergonadotrophism in male transgenic growth retarded rats. J Neuroendocrinol 2006; 18:719-31. [PMID: 16965290 DOI: 10.1111/j.1365-2826.2006.01467.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Growth hormone (GH) is known to regulate peripheral components of the hypothalamo-pituitary gonadal (HPG) axis, but it remains unclear whether GH exerts a significant influence on the activity of the hypothalamo-pituitary components of the HPG axis. In this study, we investigated the development of HPG axis function in the male transgenic growth retarded (Tgr) rat, a model of moderate systemic GH deficiency caused by hypothalamic expression of human (h)GH. Impaired postnatal somatotroph expansion and moderate GH deficiency in male Tgr rats were accompanied by a two- to three-fold increase in pituitary gonadotrophin content, but without a significant change in the pituitary gonadotroph population. A three- to nine-fold elevation in basal circulating luteinising hormone concentration was seen in postpubertal Tgr rats, with a smaller increase in follicle-stimulating hormone. Despite this hypergonadotrophism, there was no corresponding increase in steroidogenic (circulating testosterone and seminal vesicle weights) or gametogenic (spermatozoa counts in seminiferous tubules) activity in the postpubertal Tgr testis. Following puberty, the plasma leptin concentration also became progressively elevated in Tgr males. Circulating gonadotrophin and leptin levels were normalised in Tgr rats by peripheral physiological replacement of rat GH, but plasma testosterone concentration was unaffected. These results confirm that hGH exerts a positive influence on the central control of gonadotrophin secretion in the Tgr rat, but the absence of a corresponding elevation in the steroidogenic or gametogenic function of the Tgr testis implies that the peripheral GH/insulin-like growth factor I axis may also exert a permissive influence on testicular function. The relative contribution of somatogenic and lactogenic mechanisms and the potential influence of elevated leptin and decreased sensitivity to androgen feedback to the development of postpubertal hypergonadotrophism in Tgr males remain to be determined.
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Affiliation(s)
- J S Davies
- School of Biosciences, Cardiff University, Cardiff, UK
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Omer S, Meredith D, Morris JF, Christian HC. Evidence for the role of adenosine 5'-triphosphate-binding cassette (ABC)-A1 in the externalization of annexin 1 from pituitary folliculostellate cells and ABCA1-transfected cell models. Endocrinology 2006; 147:3219-27. [PMID: 16601136 DOI: 10.1210/en.2006-0099] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Annexin 1 (ANXA1), a 37-kDa protein, is a member of the superfamily of Ca(2+)- and phospholipid-binding annexin proteins. In the anterior pituitary, ANXA1 is expressed mainly by folliculostellate (FS) cells and mediates the early delayed feedback inhibition exerted by glucocorticoids on the release of ACTH and other pituitary hormones. It has been previously demonstrated that TtT/GF cells (a FS cell line) express and externalize ANXA1 in response to glucocorticoid treatment. However, ANXA1 lacks a cleavable signal sequence and externalization is not affected by inhibitors of the secretory pathway. We have previously shown that glyburide, an ATP-binding cassette (ABC) transporter inhibitor, inhibits the externalization of ANXA1 from TtT/GF cells and pituitary tissue. Here we investigated whether ABCA1 is involved in ANXA1 externalization. The use of the ABCA1-transporter inhibitors geranyl-geranyl pyrophosphate and sulfobromophthalein significantly inhibited ANXA1 externalization. Partial silencing of ABCA1 expression in TtT/GF cells by siRNA also significantly decreased the amount of cell surface ANXA1. However, anterior pituitary tissue from ABCA1-null mice was found to externalize ANXA1 normally. Because compensation by other ABC family members may occur in vivo, ANXA1 externalization was studied in two transfection models: Xenopus oocytes injected with ABCA1 mRNA and AtT20 D1 corticoctroph cells cotransfected with ABCA1-green fluorescent protein and ANXA1. ABCA1-expressing oocytes, but not water-injected controls, were found to externalize ANXA1. Expression of ABCA1 in AtT20 D1 cells significantly increased the amount of cell surface ANXA1, compared with mock-transfected and ANXA1-only transfected controls. Together these data provide evidence for a role of ABCA1 in ANXA1 export.
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Affiliation(s)
- Selma Omer
- Department of Physiology, Anatomy, and Genetics, Le Gros Clark Building, University of Oxford, South Parks Road, Oxford OX1 3QX, United Kingdom
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Solito E, Christian HC, Festa M, Mulla A, Tierney T, Flower RJ, Buckingham JC. Post-translational modification plays an essential role in the translocation of annexin A1 from the cytoplasm to the cell surface. FASEB J 2006; 20:1498-500. [PMID: 16720734 PMCID: PMC2049060 DOI: 10.1096/fj.05-5319fje] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Annexin A1 (ANXA1) has an important role in cell-cell communication in the host defense and neuroendocrine systems. In both systems, its actions are exerted extracellularly via membrane-bound receptors on adjacent sites after translocation of the protein from the cytoplasm to the cell surface of adjacent cells. This study used molecular, microscopic, and pharmacological approaches to explore the mechanisms underlying the cellular exportation of ANXA1 in TtT/GF (pituitary folliculo-stellate) cells. LPS caused serine-phosphorylation of ANXA1 (ANXA1-S27-PO4) and translocation of the phosphorylated protein to the cell membrane. The fundamental requirement of phosphorylation for membrane translocation was confirmed by immunofluorescence microscopy on cells transfected with wild-type or mutated (S27/A) ANXA1 constructs tagged with enhanced green fluorescence protein. The trafficking of ANXA1-S27-PO4 to the cell surface was dependent on PI3-kinase and MAP-kinase. It also required HMG-coenzyme A and myristoylation. The effects of HMG-coenzyme A blockade were overcome by mevalonic acid (the product of HMG-coenzyme A) and farnesyl-pyrophosphate but not by geranyl-geranylpyrophosphate or cholesterol. Together, these results suggest that serine-27 phosphorylation is essential for the translocation of ANXA1 across the cell membrane and also identify a role for isoprenyl lipids. Such lipids could target consensus sequences in ANXA1. Alternatively, they may target other proteins in the signal transduction cascade (e.g., transporters).
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Affiliation(s)
- E Solito
- Department of Cellular and Molecular Neuroscience, Division of Neuroscience and Mental Health, Imperial College London, Hammersmith Campus, Du Cane Rd., London W12 0NN, UK
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McArthur S, Siddique ZL, Christian HC, Capone G, Theogaraj E, John CD, Smith SF, Morris JF, Buckingham JC, Gillies GE. Perinatal glucocorticoid treatment disrupts the hypothalamo-lactotroph axis in adult female, but not male, rats. Endocrinology 2006; 147:1904-15. [PMID: 16439449 DOI: 10.1210/en.2005-1496] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study aimed to test the hypothesis that the tuberoinfundibular dopaminergic neurons of the arcuate nucleus and/or the lactotroph cells of the anterior pituitary gland are key targets for the programming effects of perinatal glucocorticoids (GCs). Dexamethasone was administered noninvasively to fetal or neonatal rats via the mothers' drinking water (1 mug/ml) on embryonic d 16-19 or neonatal d 1-7, and control animals received normal drinking water. At 68 d of age, the numbers of tyrosine hydroxylase-positive (TH+) cells in the arcuate nucleus and morphometric parameters of pituitary lactotrophs were analyzed. In control animals, striking sex differences in TH+ cell numbers, lactotroph cell size, and pituitary prolactin content were observed. Both pre- and neonatal GC treatment regimens were without effect in adult male rats, but in females, the overriding effect was to abolish the sex differences by reducing arcuate TH+ cell numbers (pre- and neonatal treatments) and reducing lactotroph cell size and pituitary prolactin content (prenatal treatment only) without changing lactotroph cell numbers. Changes in circulating prolactin levels represented a net effect of hypothalamic and pituitary alterations that exhibited independent critical windows of susceptibility to perinatal GC treatments. The dopaminergic neurons of the hypothalamic periventricular nucleus and the pituitary somatotroph populations were not significantly affected by either treatment regimen in either sex. These data show that the adult female hypothalamo-lactotroph axis is profoundly affected by perinatal exposure to GCs, which disrupts the tonic inhibitory tuberoinfundibular dopaminergic pathway and changes lactotroph morphology and prolactin levels in the pituitary and circulation. These findings provide new evidence for a long-term disruption in prolactin-dependent homeostasis in females, but not males, after inappropriate GC exposure in perinatal life.
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Affiliation(s)
- S McArthur
- Department of Cellular and Molecular Neuroscience, Division of Neuroscience and Mental Health, Imperial College London, UK
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41
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Huerta-Ocampo I, Christian HC, Thompson NM, El-Kasti MM, Wells T. The Intermediate lactotroph: a morphologically distinct, ghrelin-responsive pituitary cell in the dwarf (dw/dw) rat. Endocrinology 2005; 146:5012-23. [PMID: 16055430 DOI: 10.1210/en.2005-0335] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Profound somatotroph hypoplasia in the dwarf (dw/dw) rat is accompanied by an estrogen-dependent induction of prolactin secretion by the GH secretagogue, GHRP-6. Using electron microscopy, we demonstrated that the reduction in the somatotroph population in the dw/dw pituitary is accompanied by the presence of a morphologically distinct lactotroph subpopulation. In these cells, which did not coexpress GH, the size, shape, and number of the secretory granules were between those of the type I and type II lactotrophs. We therefore called these cells intermediate lactotrophs. The intermediate lactotrophs accounted for up to 30% of the total prolactin-positive cell population in dw/dw males and up to 12% in females. Using tannic acid to quantify the fusion of secretory granules, we have shown that the intermediate lactotrophs are unresponsive to either GH-releasing factor (GRF) or TRH but exhibit a sexually dimorphic secretory response to acute ghrelin treatment, granular fusions being 4-fold higher in females. No cell matching the morphology of the novel lactotroph subpopulation was observed in the pituitary of the GRF-insensitive lit/lit mouse. However, ablation of GRF neurons with neonatal monosodium glutamate treatment had no effect on the population of intermediate lactotrophs in the dw/dw rat. Thus, the presence of the intermediate lactotrophs in the dw/dw pituitary appears to be independent of the function of the GRF neurons.
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Affiliation(s)
- Icnelia Huerta-Ocampo
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, United Kingdom
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42
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Theogaraj E, John CD, Christian HC, Morris JF, Smith SF, Buckingham JC. Perinatal glucocorticoid treatment produces molecular, functional, and morphological changes in the anterior pituitary gland of the adult male rat. Endocrinology 2005; 146:4804-13. [PMID: 16099861 DOI: 10.1210/en.2005-0500] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Stress or glucocorticoid (GC) treatment in perinatal life can induce long-term changes in the sensitivity of the hypothalamo-pituitary-adrenocortical axis to the feedback actions of GCs and, hence, in GC secretion. These changes have been ascribed largely to changes in the sensitivity of the limbic system, and possibly the hypothalamus, to GCs. Surprisingly, the possibility that early life stress/GC treatment may also exert irreversible effects at the pituitary level has scarcely been addressed. Accordingly, we have examined the effects of pre- and neonatal dexamethasone treatment on the adult male pituitary gland, focusing on the following: 1) the integrity of the acute annexin 1 (ANXA1)-dependent inhibitory actions of GCs on ACTH secretion, a process requiring ANXA1 release from folliculostellate (FS) cells; and 2) the morphology of FS cells and corticotrophs. Dexamethasone was given to pregnant (d 16-19) or lactating (d 1-7 postpartum) rats via the drinking water (1 microg/ml); controls received normal drinking water. Pituitary tissue from the offspring was examined ex vivo at d 90. Both treatment regimens reduced ANXA1 expression, as assessed by Western blotting and quantitative immunogold labeling. In particular, the amount of ANXA1 located on the outer surface of the FS cells was reduced. By contrast, IL-6 expression was increased, particularly by the prenatal treatment. Pituitary tissue from untreated control rats responded to dexamethasone with an increase in cell surface ANXA1 and a reduction in forskolin-induced ACTH release. In contrast, pituitary tissue from rats treated prenatally or neonatally with dexamethasone was unresponsive to the steroid, although, like control tissue, it responded readily to ANXA1, which readily inhibited forskolin-driven ACTH release. Prenatal dexamethasone treatment reduced the size but not the number of FS cells. It also caused a marked reduction in corticotroph number and impaired granule margination without affecting other aspects of corticotroph morphology. Similar but less marked effects on pituitary cell morphology and number were evident in tissue from neonatally treated rats. Our study shows that, when administered by a noninvasive process, perinatal GC treatment exerts profound effects on the adult pituitary gland, impairing the ANXA1-dependent GC regulation of ACTH release and altering the cell profile and morphology.
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Affiliation(s)
- E Theogaraj
- Department of Cellular and Molecular Neuroscience, Division of Neuroscience and Mental Health, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
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Getting SJ, Di Filippo C, Christian HC, Lam CW, Rossi F, D'Amico M, Perretti M. MC-3 receptor and the inflammatory mechanisms activated in acute myocardial infarct. J Leukoc Biol 2004; 76:845-53. [PMID: 15277567 DOI: 10.1189/jlb.0306175] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Investigation of the mechanisms activated by endogenous inhibitory pathways can lead to identification of novel targets for cardiovascular inflammatory pathologies. Here we exploited the potential protective role that melanocortin receptor type 3 (MC3-R) activation might play in a myocardial ischemia-reperfusion injury model. In resting conditions, mouse and rat heart extracts expressed MC3-R mRNA and protein, without changes following ischemia-reperfusion. At the cellular level heart macrophages, but not fibroblasts or cardiomyocytes, expressed this receptor, as demonstrated by immunogold labeling. In vivo, administration of the melanocortin agonist MTII (10 microg per mouse equivalent to 9.3 nmol) 30 min prior to ischemia (25 min) attenuated mouse heart 2 h reperfusion injury by approximately 40%, an effect prevented by the mixed MC3/4-R antagonist SHU9119 but not by the selective MC4-R antagonist HS204. Similar results were obtained when the compound was given at the beginning of the reperfusion period. Importantly, delayed myocardial damage as measured 24 h post-reperfusion was equally protected by administration of 10 microg MTII. The focus on MC3-R was also substantiated by analysis of the recessive yellow (e/e) mouse, bearing a mutated (inactive) MC1-R, in which MTII was fully protective. Myocardial protection was associated with reduced markers of systemic and local inflammation, including cytokine contents (interleukin-1 and KC) and myeloperoxidase activity. In conclusion, this study has highlighted a previously unrecognized protective role for MC3-R activation on acute and delayed heart reperfusion injury. These data may open new avenues for therapeutic intervention against heart and possibly other organ ischemia-reperfusion injury.
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MESH Headings
- Acute Disease
- Animals
- Fibroblasts/drug effects
- Fibroblasts/metabolism
- Interleukin-1/metabolism
- Macrophages/drug effects
- Macrophages/metabolism
- Melanocyte-Stimulating Hormones/pharmacology
- Mice
- Mutation
- Myocardial Infarction/immunology
- Myocardial Infarction/pathology
- Myocardial Reperfusion Injury/immunology
- Myocardial Reperfusion Injury/prevention & control
- Myocardium/immunology
- Myocardium/pathology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Peptides, Cyclic/pharmacology
- Peroxidase/metabolism
- Rats
- Receptor, Melanocortin, Type 3/agonists
- Receptor, Melanocortin, Type 3/antagonists & inhibitors
- Receptor, Melanocortin, Type 3/physiology
- Receptors, Corticotropin/antagonists & inhibitors
- alpha-MSH/analogs & derivatives
- alpha-MSH/pharmacology
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Abstract
Annexin 1 (ANXA1) was first identified as a mediator of the anti-inflammatory actions of glucocorticoids in the host defence system. Subsequent work revealed that this protein fulfils a wider brief and it is now recognized as an important signalling intermediate in a variety of other systems. Here, we consider the role of ANXA1 in the endocrine system, placing particular emphasis on new insights into the mechanisms and functional significance of the secondary processing of ANXA1, the processes that control the intracellular and transmembrane trafficking of the molecule and the molecular mechanisms of ANXA1 action that have identified a novel role for the protein as a paracrine/juxtacrine mediator of the non-genomic actions of glucocorticoids in the neuroendocrine system.
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Affiliation(s)
- Christopher D John
- Cellular and Molecular Neuroscience, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W120NN, UK
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Mulla A, Christian HC, Solito E, Mendoza N, Morris JF, Buckingham JC. Expression, subcellular localization and phosphorylation status of annexins 1 and 5 in human pituitary adenomas and a growth hormone-secreting carcinoma. Clin Endocrinol (Oxf) 2004; 60:107-19. [PMID: 14678296 DOI: 10.1111/j.1365-2265.2004.01936.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Annexin 1 (ANXA1), a 37-kDa protein, plays an important role as a mediator of glucocorticoid action in the anterior pituitary gland and has been implicated in the processes of tumorigenesis in a number of other tissues. As a prelude to examining the potential role of ANXA1 in the pathophysiology of pituitary tumours, this study examined the expression, phosphorylation status and distribution of ANXA1 and the closely related protein, annexin 5 (ANXA5), in a series of pituitary adenomas and in two carcinomas. PATIENTS AND DESIGN Forty-two human pituitary adenomas were examined. Parallel studies were performed on normal pituitary tissue, obtained postmortem, a GH-secreting carcinoma and a grade 4 astrocytoma. MEASUREMENTS The tissue was processed for analysis of ANXA1 mRNA and protein expression by reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analysis and immunogold electron-microscopic histochemistry. Parallel measures of ANXA5 mRNA and protein were also made. RESULTS ANXA1 mRNA and protein were detected in all but three adenomas studied; the protein was localized mainly, but not exclusively, to nonendocrine cells. ANXA5 expression was more variable and was contained within both endocrine and nonendocrine cells of these tumours. In comparison with the adenomas, the GH-secreting carcinoma showed abundant expression of both ANXA1 and ANXA5, with intense ANXA1 staining in some but not all tumour/endocrine cells. A serine-phosphorylated species of ANXA1 was detected in all pituitary tumours studied; by contrast, tyrosine-phosphorylated ANXA1 was detected in only four adenomas and in the GH carcinoma. ANXA1 and ANXA5 were also expressed in abundance in the astrocytoma. CONCLUSIONS The results demonstrate expression of both ANXA1 and ANXA5 in human pituitary tumours and thus raise the possibility that these proteins influence the growth and/or functional activity of the tumours.
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Affiliation(s)
- Abeda Mulla
- Department of Cellular and Molecular Neuroscience, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, Imperial College London, Commonwealth Building, Hammersmith Hospital Campus, Du Cane Road, London, UK
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Tierney T, Christian HC, Morris JF, Solito E, Buckingham JC. Evidence from studies on co-cultures of TtT/GF and AtT20 cells that Annexin 1 acts as a paracrine or juxtacrine mediator of the early inhibitory effects of glucocorticoids on ACTH release. J Neuroendocrinol 2003; 15:1134-43. [PMID: 14636175 DOI: 10.1111/j.1365-2826.2003.01111.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Annexin 1 (ANXA1) is a key mediator of the inhibitory effects of glucocorticoids on adrenocorticotropic hormone (ACTH) release, which develop within 1-2 h of a steroid challenge. Our previous studies, which showed that (i) ANXA1 is expressed principally by the nonsecretory folliculo-stellate cells in the pituitary gland; (ii) glucocorticoids cause the exportation of ANXA1 from these cells; and (iii) corticotrophs express specific ANXA1 binding sites, led us to propose that ANXA1 serves as a paracrine or juxtacrine mediator of glucocorticoids. To address this hypothesis, we examined ANXA1-dependent glucocorticoid actions in co-cultures of murine corticotroph (AtT20 clone D1) and folliculo-stellate (TtT/GF) cell lines. ANXA1 mRNA and protein were found in abundance in TtT/GF cells but neither was detectable in the AtT20 cells. AtT20 cells (alone and in co-culture with TtT/GF cells) responded to corticotropin-releasing hormone (CRH) (0.1-1 micro m) with increased ACTH release. The CRH-stimulated release of ACTH from AtT20 cells cultured alone was unaffected by preincubation with dexamethasone (Dex, 100 nm); by contrast, in co-cultures of AtT20 and TtT/GF cells, the steroid readily inhibited the secretory response to CRH. The effects of Dex on ACTH release were mimicked by N-terminal ANXA1 fragments (ANXA1Ac2-26, 2 micro g/ml and ANXA11-188, 0.1 ng/ml) and reversed by mifepristone (1 micro m) and by an antisense oligodeoxynucleotide (ODN) to ANXA1 (50 nm) but not by control ODNs. The antisense ODN also specifically blocked the Dex-induced externalization of ANXA1 from TtT/GF cells. Immunofluorescence imaging of the co-cultures localized the exported protein to the vicinity of the AtT20 cells and identified ANXA1 binding sites on these cells. These results provide functional and histological evidence to support our premise that the early inhibitory effects of glucocorticoids on ACTH release are dependent upon paracrine/juxtacrine actions of ANXA1 derived from folliculo-stellate cells.
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Affiliation(s)
- T Tierney
- Department of Neuroendocrinology, Division of Neuroscience and Psychological Medicine, Imperial College London, London, UK
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47
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John CD, Christian HC, Morris JF, Flower RJ, Solito E, Buckingham JC. Kinase-dependent regulation of the secretion of thyrotrophin and luteinizing hormone by glucocorticoids and annexin 1 peptides. J Neuroendocrinol 2003; 15:946-57. [PMID: 12969239 DOI: 10.1046/j.1365-2826.2003.01081.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Our previous studies have identified a role for annexin 1 (ANXA1), a protein produced by the pituitary folliculostellate cells, as a paracrine/juxtacrine mediator of the acute regulatory effects of glucocorticoids on the release of adrenocorticotropic hormone and other pituitary hormones. In the present study, we focused on the secretion of thyroid stimulating hormone (TSH) and luteinizing hormone (LH) and used a battery of ANXA1-derived peptides to identify the key domains in the ANXA1 molecule that are critical to the inhibition of peptide release. In addition, as ANXA1 is a substrate for protein kinase C (PKC) and tyrosine kinase, we examined the roles of these kinases in the manifestation of the ANXA1-dependent inhibitory actions of dexamethasone on TSH and LH release. Dexamethasone suppressed the forskolin-induced release of TSH and LH from rat anterior pituitary tissue in vitro. Its effects were mimicked by human recombinant ANXA1 (hrANXA1) and a truncated protein, ANXA1(1-188). ANXA1(Ac2-26), also suppressed stimulated peptide release but it lacked both the potency and the efficacy of the parent protein. Shorter N-terminal ANXA1 sequences were without effect. The PKC inhibitor PKC(19-36) abolished the inhibitory actions of dexamethasone on the forskolin-evoked release of TSH and LH; it also attenuated the inhibitory actions of ANXA1(Ac2-26). Similar effects were produced by annexin 5 (ANXA5) which sequesters PKC in other systems. By contrast, the tyrosine kinase inhibitors, p60v-src (137-157) and genistein, had no effect on the secretion of TSH or LH alone or in the presence of forskolin and/or dexamethasone. Dexamethasone caused the translocation of a tyrosine-phosphorylated species of ANXA1 to the surface of pituitary cells. The total amount of ANXA1 exported from the cells in response to the steroid was unaffected by tyrosine kinase blockade. However, the degree of tyrosine-phosphorylation of the exported protein was markedly reduced by genistein. These results suggest that (i) the ANXA1-dependent inhibitory actions of dexamethasone on the release of TSH and LH require PKC and sequences in the N-terminal domain of ANXA1, but are independent of tyrosine kinase, and (ii) while dexamethasone induces the cellular exportation of a tyrosine-phosphorylated species of ANXA1, tyrosine phosphorylation per se is not critical to the steroid-induced passage of ANXA1 across the membrane.
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Affiliation(s)
- C D John
- Department of Neuroendocrinology, Division of Neuroscience and Psychological Medicine, Imperial College London, London, UK
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48
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Solito E, Mulla A, Morris JF, Christian HC, Flower RJ, Buckingham JC. Dexamethasone induces rapid serine-phosphorylation and membrane translocation of annexin 1 in a human folliculostellate cell line via a novel nongenomic mechanism involving the glucocorticoid receptor, protein kinase C, phosphatidylinositol 3-kinase, and mitogen-activated protein kinase. Endocrinology 2003; 144:1164-74. [PMID: 12639897 DOI: 10.1210/en.2002-220592] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Our recent studies on rat pituitary tissue suggest that the annexin 1 (ANXA1)-dependent inhibitory actions of glucocorticoids on ACTH secretion are effected via a paracrine mechanism that involves protein kinase C (PKC)-dependent translocation of a serine-phosphorylated species of ANXA1 (Ser-P-ANXA1) to the plasma membrane of the nonsecretory folliculostellate cells. In the present study, we have used a human folliculostellate cell line (PDFS) to explore the signaling mechanisms that cause the translocation of Ser-P-ANXA1 to the membrane together with Western blot analysis and flow cytometry to detect the phosphorylated protein. Exposure of PDFS cells to dexamethasone caused time-dependent increases in the expression of ANXA1 mRNA and protein, which were first detected within 2 h of steroid contact. This genomic response was preceded by the appearance within 30 min of substantially increased amounts of Ser-P-ANXA1 and by translocation of the phosphorylated protein to the cell surface. The prompt membrane translocation of Ser-P-ANXA1 provoked by dexamethasone was inhibited by the glucocorticoid receptor, antagonist, mifepristone, but not by actinomycin D or cycloheximide, which effectively inhibit mRNA and protein synthesis respectively in our preparation. It was also inhibited by a nonselective PKC inhibitor (PKC(9-31)), by a selective inhibitor of Ca(2+)-dependent PKCs (Go 6976) and by annexin 5 (which sequesters PKC in other systems). In addition, blockade of phosphatidylinositiol 3-kinase (wortmannin) or MAPK pathways with PD 98059 or UO 126 (selective for MAPK kinse 1 and 2) prevented the steroid-induced translocation of Ser-P-ANXA1 to the cell surface. These results suggest that glucocorticoids induce rapid serine phosphorylation and membrane translocation of ANXA1 via a novel nongenomic, glucocorticoid receptor-dependent mechanism that requires MAPK, phosphatidylinositiol 3-kinase, and Ca(2+)-dependent PKC pathways.
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Affiliation(s)
- Egle Solito
- Department of Neuroendocrinology, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 ONN, United Kingdom.
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Getting SJ, Christian HC, Lam CW, Gavins FNE, Flower RJ, Schiöth HB, Perretti M. Redundancy of a functional melanocortin 1 receptor in the anti-inflammatory actions of melanocortin peptides: studies in the recessive yellow (e/e) mouse suggest an important role for melanocortin 3 receptor. J Immunol 2003; 170:3323-30. [PMID: 12626592 DOI: 10.4049/jimmunol.170.6.3323] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The issue of which melanocortin receptor (MC-R) is responsible for the anti-inflammatory effects of melanocortin peptides is still a matter of debate. Here we have addressed this aspect using a dual pharmacological and genetic approach, taking advantage of the recent characterization of more selective agonists/antagonists at MC1 and MC3-R as well as of the existence of a naturally defective MC1-R mouse strain, the recessive yellow (e/e) mouse. RT-PCR and ultrastructural analyses showed the presence of MC3-R mRNA and protein in peritoneal macrophages (M phi) collected from recessive yellow (e/e) mice and wild-type mice. This receptor was functional as Mphi incubation (30 min) with melanocortin peptides led to accumulation of cAMP, an effect abrogated by the MC3/4-R antagonist SHU9119, but not by the selective MC4-R antagonist HS024. In vitro M phi activation, determined as release of the CXC chemokine KC and IL-1 beta, was inhibited by the more selective MC3-R agonist gamma(2)-melanocyte stimulating hormone but not by the selective MC1-R agonist MS05. Systemic treatment of mice with a panel of melanocortin peptides inhibited IL-1 beta release and PMN accumulation elicited by urate crystals in the murine peritoneal cavity. MS05 failed to inhibit any of the inflammatory parameters either in wild-type or recessive yellow (e/e) mice. SHU9119 prevented the inhibitory actions of gamma(2)-melanocyte stimulating hormone both in vitro and in vivo while HS024 was inactive in vivo. In conclusion, agonism at MC3-R expressed on peritoneal M phi leads to inhibition of experimental nonimmune peritonitis in both wild-type and recessive yellow (e/e) mice.
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MESH Headings
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/metabolism
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Cell Movement/genetics
- Cells, Cultured
- Crystallization
- Cytokines/antagonists & inhibitors
- Cytokines/metabolism
- Genes, Recessive
- Injections, Intraperitoneal
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/pathology
- Male
- Melanocyte-Stimulating Hormones/metabolism
- Melanocyte-Stimulating Hormones/pharmacology
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Peritonitis/chemically induced
- Peritonitis/genetics
- Peritonitis/pathology
- Pigmentation/genetics
- Receptor, Melanocortin, Type 3
- Receptors, Corticotropin/agonists
- Receptors, Corticotropin/antagonists & inhibitors
- Receptors, Corticotropin/genetics
- Receptors, Corticotropin/physiology
- Receptors, Melanocortin
- Uric Acid/toxicity
- gamma-MSH/antagonists & inhibitors
- gamma-MSH/pharmacology
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Affiliation(s)
- Stephen J Getting
- Department of Biochemical Pharmacology, The William Harvey Research Institute, Bart's and The London, Queen Mary's School of Medicine and Dentistry, London, United Kingdom.
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50
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Chapman LP, Epton MJ, Buckingham JC, Morris JF, Christian HC. Evidence for a role of the adenosine 5'-triphosphate-binding cassette transporter A1 in the externalization of annexin I from pituitary folliculo-stellate cells. Endocrinology 2003; 144:1062-73. [PMID: 12586783 DOI: 10.1210/en.2002-220650] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Annexin 1 (ANXA1) has a well-demonstrated role in early delayed inhibitory feedback of glucocorticoids in the pituitary. ANXA1 is located in folliculo-stellate (FS) cells, and glucocorticoids act on these cells to externalize and stimulate the synthesis of ANXA1. However, ANXA1 lacks a signal sequence so the mechanism by which ANXA1 is externalized from FS cells was unknown and has been investigated. The ATP-binding cassette (ABC) transporters are a large group of transporters with varied roles that include the externalization of proteins. Glucocorticoid-induced externalization of ANXA1 from an FS cell line (TtT/GF) and rat anterior pituitary was blocked by glyburide, which inhibits ABC transporters. Glyburide also blocked the glucocorticoid inhibition of forskolin-stimulated ACTH release from pituitary tissue in vitro. RT-PCR revealed mRNA and Western blotting demonstrated protein for the ATP binding cassette A1 (ABCA1) transporter in mouse FS, TtT/GF, and A549 lung adenocarcinoma cells from which glucocorticoids also induce externalization of ANXA1. In TtT/GF cells, immunofluorescence labeling revealed a near total colocalization of cell surface ANXA1 and ABCA1. We conclude that ANXA1, which mediates the early delayed feedback of glucocorticoids in the anterior pituitary, is externalized from FS cells by an ABC transporter and that the ABCA1 transporter is a likely candidate.
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Affiliation(s)
- Lee P Chapman
- Department of Human Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, United Kingdom
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