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Guillemot J, Guérin M, Cailleux AF, Lopez AG, Kuhn JM, Anouar Y, Yon L. Characterization of the EM66 Biomarker in the Pituitary and Plasma of Healthy Subjects With Different Gonadotroph Status and Patients With Gonadotroph Tumor. Front Endocrinol (Lausanne) 2019; 10:102. [PMID: 30853937 PMCID: PMC6395403 DOI: 10.3389/fendo.2019.00102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 02/04/2019] [Indexed: 12/05/2022] Open
Abstract
Granins and their derived-peptides are useful markers of secretion from normal and tumoral neuroendocrine cells. The need to identify new diagnostic markers for neuroendocrine tumors, including pituitary tumors prompted us to determine plasma levels of the secretogranin II-derived peptide EM66 in healthy volunteers with different gonadotroph status and to evaluate its usefulness as a circulating marker for the diagnosis of gonadotroph tumor. Using a radioimmunoassay, we determined plasma EM66 concentrations in healthy men and women volunteers in different physiological conditions in relation with the gonadotroph function. Our results revealed that in men, in women with or without contraception, in pregnant or post-menopausal women, plasma EM66 concentrations are not significantly different, and did not show any correlation with gonadotropin levels. In addition, stimulation or inhibition tests of the gonadotroph axis had no effect on EM66 levels, whatever the group of healthy volunteers investigated while gonadotropin levels showed the expected variations. Immunohistochemical experiments and HPLC analysis showed the occurrence of EM66 in pituitary gonadotroph, lactotroph and corticotroph tumors but not in somatotroph tumor. In patients with gonadotroph or lactotroph tumor, plasma EM66 levels were 1.48 (0.82-4.38) ng/ml and 2.49 (1.19-3.54) ng/ml, respectively. While median value of EM66 was significantly lower in patients with gonadotroph tumor compared to healthy volunteers [2.59 (0.62-4.95) ng/ml], plasma EM66 concentrations were in the same range as normal values and did not show any correlation with gonadotropin levels. These results show that plasma EM66 levels are independent of the activity of the gonadotroph axis in healthy volunteers and, while EM66 levels are reduced in gonadotroph tumors, plasma EM66 does not provide a helpful marker for the diagnosis of these tumors.
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Affiliation(s)
- Johann Guillemot
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandie Univ, UNIROUEN, INSERM, Rouen, France
| | - Marlène Guérin
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandie Univ, UNIROUEN, INSERM, Rouen, France
| | - Anne-Françoise Cailleux
- Endocrinology, Diabetes and Metabolism Department, Normandie Univ, UNIROUEN, Rouen University Hospital, INSERM CIC-CRB, Rouen, France
| | - Antoine-Guy Lopez
- Department of Endocrinology, Diabetes and Metabolic Diseases, Normandie Univ, UNIROUEN, Rouen University Hospital, Rouen, France
| | - Jean-Marc Kuhn
- Endocrinology, Diabetes and Metabolism Department, Normandie Univ, UNIROUEN, Rouen University Hospital, INSERM CIC-CRB, Rouen, France
| | - Youssef Anouar
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandie Univ, UNIROUEN, INSERM, Rouen, France
| | - Laurent Yon
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandie Univ, UNIROUEN, INSERM, Rouen, France
- *Correspondence: Laurent Yon
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Nestorović N, Trifunović S, Manojlović-Stojanoski M, Jarić I, Ristić N, Filipović B, Šošić-Jurjević B, Milošević V. Soy Phytoestrogens Do Not Fully Reverse Changes in Rat Pituitary Castration Cells: Unbiased Stereological Study. Anat Rec (Hoboken) 2018; 301:1416-1425. [PMID: 29569839 DOI: 10.1002/ar.23809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 01/04/2018] [Accepted: 01/18/2018] [Indexed: 02/07/2023]
Abstract
The aim of the study was to examine the potential of the principal soy isoflavones, genistein and daidzein, or isoflavone rich soy extract to recover pituitary castration cells in orchidectomized adult male rats in comparison with the effects of estradiol. Two weeks post orchidectomy (Orx), animals received estradiol-dipropionate, genistein, daidzein or soy extract subcutaneously for 3 weeks. Control sham-operated (So) and Orx rats received just the vehicle. Changes in the volumes of pars distalis, of individual follicle-stimulating hormone (FSH) and luteinizing hormone (LH) containing cells, their volume, numerical density and number were determined by unbiased design-based stereology. The intracellular content of βFSH and βLH was estimated by relative intensity of fluorescence (RIF). Orchidectomy increased all examined stereological parameters and RIF. Compared to Orx, estradiol increased the volume of pars distalis, but reversed RIF and all morphometric parameters of gonadotropes to the level of So rats, except their number. Treatments with purified isoflavones and soy extract decreased RIF to the control So level, expressing an estradiol-like effect. However, the histological appearance and morphometrical features of gonadotropes did not follow this pattern. Genistein increased the volume of pars distalis, decreased the volume density of LH-labeled cells and raised the number of gonadotropes. Daidzein decreased the cell volume of gonadotropic cells but increased their number and numerical density. Soy extract induced an increase in number and numerical density of FSH-containing cells. Therefore, it can be concluded that soy phytoestrogens do not fully reverse the Orx-induced changes in pituitary castration cells. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Nataša Nestorović
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Svetlana Trifunović
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Milica Manojlović-Stojanoski
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Ivana Jarić
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Nataša Ristić
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Branko Filipović
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Branka Šošić-Jurjević
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
| | - Verica Milošević
- Department of Cytology, University of Belgrade, Institute for Biological Research "Siniša Stanković,", Belgrade, 11060, Serbia
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Maeda Y, Kudo S, Tsushima K, Sato E, Kubota C, Kayamori A, Bochimoto H, Koga D, Torii S, Gomi H, Watanabe T, Hosaka M. Impaired Processing of Prohormones in Secretogranin III-Null Mice Causes Maladaptation to an Inadequate Diet and Stress. Endocrinology 2018; 159:1213-1227. [PMID: 29281094 DOI: 10.1210/en.2017-00636] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 12/15/2017] [Indexed: 11/19/2022]
Abstract
Secretogranin III (SgIII), a member of the granin family, binds both to another granin, chromogranin A (CgA), and to a cholesterol-rich membrane that is destined for secretory granules (SGs). The knockdown of SgIII in adrenocorticotropic hormone (ACTH)-producing AtT-20 cells largely impairs the regulated secretion of CgA and ACTH. To clarify the physiological roles of SgIII in vivo, we analyzed hormone secretion and SG biogenesis in newly established SgIII-knockout (KO) mice. Although the SgIII-KO mice were viable and fertile and exhibited no overt abnormalities under ordinary rearing conditions, a high-fat/high-sucrose diet caused pronounced obesity in the mice. Furthermore, in the SgIII-KO mice compared with wild-type (WT) mice, the stimulated secretion of active insulin decreased substantially, whereas the storage of proinsulin increased in the islets. The plasma ACTH was also less elevated in the SgIII-KO mice than in the WT mice after chronic restraint stress, whereas the storage level of the precursor proopiomelanocortin in the pituitary gland was somewhat increased. These findings suggest that the lack of SgIII causes maladaptation of endocrine cells to an inadequate diet and stress by impairing the proteolytic conversion of prohormones in SGs, whereas SG biogenesis and the basal secretion of peptide hormones under ordinary conditions are ensured by the compensatory upregulation of other residual granins or factors.
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Affiliation(s)
- Yoshinori Maeda
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Saki Kudo
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Ken Tsushima
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Eri Sato
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Chisato Kubota
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Aika Kayamori
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
| | - Hiroki Bochimoto
- Health Care Administration Center, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Daisuke Koga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Seiji Torii
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Masahiro Hosaka
- Department of Biotechnology, Laboratory of Molecular Life Sciences, Akita Prefectural University, Akita, Japan
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Luan X, Cao Z, Xing Z, Liu M, Gao M, Meng B, Fan R. Comparative proteomic analysis of pituitary glands from Huoyan geese between pre-laying and laying periods using an iTRAQ-based approach. PLoS One 2017; 12:e0185253. [PMID: 28945779 PMCID: PMC5612699 DOI: 10.1371/journal.pone.0185253] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 09/08/2017] [Indexed: 12/31/2022] Open
Abstract
In this study, we performed a comprehensive evaluation of the proteomic profile of the pituitary gland of the Huoyan goose during the laying period compared to the pre-laying period using an iTRAQ-based approach. Protein samples were prepared from pituitary gland tissues of nine pre-laying period and nine laying period geese. Then the protein samples from three randomly selected geese within each period were pooled in equal amounts to generate one biological sample pool. We identified 684 differentially expressed proteins, including 418 up-regulated and 266 down-regulated proteins. GO annotation and KEGG pathway analyses of these proteins were conducted. Some of these proteins were found to be associated with hormone and neurotransmitter secretion and transport, neuropeptide signalling and GnRH signalling pathways, among others. Subsequently, the modification of the abundance of three proteins (prolactin, chromogranin-A and ITPR3) was verified using western blotting. Our results will provide a new source for mining genes and gene products related to the egg-laying performance of Huoyan geese, and may provide important information for the conservation and utilization of local goose breeds.
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Affiliation(s)
- Xinhong Luan
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
- * E-mail:
| | - Zhongzan Cao
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
| | - Zhe Xing
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
| | - Mei Liu
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
| | - Ming Gao
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
| | - Bo Meng
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
| | - Ruiming Fan
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science & Veterinary Medicine, Shenyang Agricultural University, Shenyang, P.R. China
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Gomi H, Morikawa S, Shinmura N, Moki H, Yasui T, Tsukise A, Torii S, Watanabe T, Maeda Y, Hosaka M. Expression of Secretogranin III in Chicken Endocrine Cells: Its Relevance to the Secretory Granule Properties of Peptide Prohormone Processing and Bioactive Amine Content. J Histochem Cytochem 2015; 63:350-66. [PMID: 25673289 PMCID: PMC4409946 DOI: 10.1369/0022155415575032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/05/2015] [Indexed: 01/27/2023] Open
Abstract
The expression of secretogranin III (SgIII) in chicken endocrine cells has not been investigated. There is limited data available for the immunohistochemical localization of SgIII in the brain, pituitary, and pancreatic islets of humans and rodents. In the present study, we used immunoblotting to reveal the similarities between the expression patterns of SgIII in the common endocrine glands of chickens and rats. The protein-protein interactions between SgIII and chromogranin A (CgA) mediate the sorting of CgA/prohormone core aggregates to the secretory granule membrane. We examined these interactions using co-immunoprecipitation in chicken endocrine tissues. Using immunohistochemistry, we also examined the expression of SgIII in a wide range of chicken endocrine glands and gastrointestinal endocrine cells (GECs). SgIII was expressed in the pituitary, pineal, adrenal (medullary parts), parathyroid, and ultimobranchial glands, but not in the thyroid gland. It was also expressed in GECs of the stomach (proventriculus and gizzard), small and large intestines, and pancreatic islet cells. These SgIII-expressing cells co-expressed serotonin, somatostatin, gastric inhibitory polypeptide, glucagon-like peptide-1, glucagon, or insulin. These results suggest that SgIII is expressed in the endocrine cells that secrete peptide hormones, which mature via the intragranular enzymatic processing of prohormones and physiologically active amines in chickens.
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Affiliation(s)
- Hiroshi Gomi
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Satomi Morikawa
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Naoki Shinmura
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Hiroaki Moki
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Tadashi Yasui
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Azuma Tsukise
- Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Fujisawa, Japan (HG, SM, NS, HM, TY, AT)
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan (ST)
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical College, Asahikawa, Japan (TW)
| | - Yoshinori Maeda
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan (YM, MH)
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan (YM, MH)
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Watanabe T, Bochimoto H, Koga D, Hosaka M, Ushiki T. Functional implications of the Golgi and microtubular network in gonadotropes. Mol Cell Endocrinol 2014; 385:88-96. [PMID: 24121198 DOI: 10.1016/j.mce.2013.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/30/2013] [Accepted: 10/01/2013] [Indexed: 02/01/2023]
Abstract
In contrast to the widely accepted images of the Golgi apparatus as a cup-like shape, the Golgi in pituitary gonadotropes is organized as a spherical shape in which the outer and inner faces are cis- and trans-Golgi elements, respectively. At the center of the spherical Golgi, a pair of centrioles is situated as a microtubule-organizing center from which radiating microtubules isotropically extend toward the cell periphery. This review focuses on the significance of the characteristic organization of the Golgi and microtubule network in gonadotropes, considering the roles of microtubule-dependent membrane transport in the formation and maintenance of the Golgi structure. Because the highly symmetrical organization of the Golgi is possibly perturbed in response to experimental treatments of gonadotropes, monitoring of the Golgi structure in gonadotropes under various experimental conditions will be a novel in vivo approach to elucidate the biogenesis of the Golgi apparatus.
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Affiliation(s)
- Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan.
| | - Hiroki Bochimoto
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Daisuke Koga
- Division of Microscopic Anatomy and Bio-imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masahiro Hosaka
- Laboratory of Molecular Life Sciences, Department of Biotechnology, Akita Prefectural University, Akita, Japan
| | - Tatsuo Ushiki
- Division of Microscopic Anatomy and Bio-imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Abel MH, Charlton HM, Huhtaniemi I, Pakarinen P, Kumar TR, Christian HC. An investigation into pituitary gonadotrophic hormone synthesis, secretion, subunit gene expression and cell structure in normal and mutant male mice. J Neuroendocrinol 2013; 25:863-75. [PMID: 23895394 PMCID: PMC5599115 DOI: 10.1111/jne.12081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 07/16/2013] [Accepted: 07/24/2013] [Indexed: 01/30/2023]
Abstract
To investigate brain-pituitary-gonadal inter-relationships, we have compared the effects of mutations that perturb the hypothalamic-pituitary-gonadal axis in male mice. Specifically, serum and pituitary gonadotrophin concentrations, gonadotrophin gene expression, and gonadotroph structure and number were measured. Follicle-stimulating hormone (FSH)β knockout (FSHβKO), FSH receptor knockout (FSHRKO), luteinising hormone (LH) receptor knockout (LuRKO), hypogonadal (hpg), testicular feminised (tfm) and gonadectomised mice were compared with control wild-type mice or heterozygotes. Serum levels of LH were similar in FSHβKO, FSHRKO and heterozygote males despite decreased androgen production in KO males. As expected, there was no detectable FSH in the serum or pituitary and an absence of expression of the FSHβ subunit gene in FSHβKO mice. However, there was a significant increase in expression of the common α and LHβ subunit genes in FSHRKO males. The morphology of FSHβKO and FSHRKO gonadotrophs was not significantly different from controls, except that the subpopulation of granules consisting of an electron-dense core and electron-lucent 'halo' was not observed in FSHβKO gonadotrophs and the granules were smaller in diameter. In the gonadotrophin-releasing hormone deficient hpg mouse, gonadotrophin mRNA and hormone levels were significantly lower compared to control mice and gonadotrophs were correspondingly smaller, with less abundant endoplasmic reticulum and reduced secretory granules. In LuRKO, tfm and gonadectomised mice, hyperstimulation of LHβ and FSHβ mRNA and serum protein concentrations was reflected by subcellular changes in gonadotroph morphology, including more dilated rough endoplasmic reticulum and more secretory granules distributed adjacent to the plasma membrane. In summary, major differences in pituitary content and serum concentrations of the gonadotrophins LH and FSH have been found between normal and mutant male mice. These changes are associated with changes in transcriptional activity of the gonadotrophin subunit genes and are reflected by changes in the cellular structure and secretory granule architecture within the gonadotroph cells.
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Affiliation(s)
- M. H. Abel
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - H. M. Charlton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - I. Huhtaniemi
- Department of Physiology, University of Turku, Turku, Finland
| | - P. Pakarinen
- Department of Physiology, University of Turku, Turku, Finland
| | - T. R. Kumar
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center,, Kansas City, KS, USA
| | - H. C. Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Hosaka M, Watanabe T, Sakai Y, Kato T, Takeuchi T. Interaction between secretogranin III and carboxypeptidase E facilitates prohormone sorting within secretory granules. J Cell Sci 2006; 118:4785-95. [PMID: 16219686 DOI: 10.1242/jcs.02608] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Secretogranin III (SgIII) and carboxypeptidase E (CPE) bind specifically to cholesterol-rich secretory granule (SG) membranes. We previously showed that SgIII binds chromogranin A (CgA) and targets CgA to the SGs in endocrine cells. We investigated the binding of SgIII and CPE because they frequently localize close to the periphery of SGs, and they bind each other in mouse corticotrope-derived AtT-20 cells. In Cpe fat mouse corticotropes, which have defective CPE, proopiomelanocortin (POMC)-derived adrenocorticotrophin hormone (ACTH)-containing peptides were distributed over the entire surface of the SGs, and displayed a regulated secretion by secretagogues. The Cpe fat pituitary exhibited elevated levels of SgIII and CgA, which suggests that they compensate for a sorting function of CPE for POMC and its intermediates to ACTH. Indeed, both SgIII and CgA were able to bind POMC-derived intermediates. In a competitive pull-down assay, excessive SgIII led to a decrease in CPE-bound POMC-derived intermediate molecules, and SgIII pulled-down by anti-ACTH antibody increased proportionately. We suggest that SgIII and CPE form the separate functional sorting complex by anchoring to cholesterol-rich SG membranes, and POMC-derived peptides are transferred from CPE to SgIII, and subsequently to CgA.
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Affiliation(s)
- Masahiro Hosaka
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
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Crawford JL, McNeilly JR, McNeilly AS. No Evidence for Pituitary Priming to Gonadotropin-Releasing Hormone in Relation to Luteinizing Hormone (LH) Secretion Prior to the Preovulatory LH Surge in Ewes1. Biol Reprod 2004; 71:224-35. [PMID: 15031142 DOI: 10.1095/biolreprod.104.027615] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The purpose of this study was to determine the occurrence of and the regulatory mechanisms involved in priming of the pituitary to GnRH before the preovulatory LH surge in sheep. Experiment 1: Forty-two ewes had progestagen devices removed after 14 days and were assigned to luteal (Lut) or follicular (Foll) groups. Fifteen days later, blood sampling was initiated either immediately or 36 h after induced luteolysis in groups Lut and Foll, respectively. After 4 h, ewes were administered either saline (n = 5) or 250 ng (n = 8) or 10 microg (n = 8) of GnRH. Five ewes per treatment group were killed 1 h later, while remaining animals were blood sampled for a further 7 h. Experiment 2: Eighteen ewes were allocated to Lut and Foll groups (described above). Blood samples were collected from 2 h before GnRH (10 microg) treatment until 7 h after. Despite up-regulated GnRH-R mRNA levels in Foll ewes, pituitary content and plasma levels of LH and LHbeta mRNA levels were similar between groups. Mean FSHbeta mRNA and plasma FSH levels were elevated in Lut ewes but declined after GnRH treatment. Inversely, plasma estradiol and inhibin-A concentrations were higher in Foll ewes and declined after GnRH treatment. Fewer LH(+ve)/secretogranin II(-ve) (SgII(-ve)) granules were present in gonadotropes of Foll ewes, coincident with increased basal LH levels. Fewer smaller sized granules were present after GnRH treatment. In conclusion, there was no evidence of self-priming before onset of the preovulatory LH surge. Constitutive release of LH(+ve)/SgII(-ve) granules may maintain basal LH levels while smaller sized, presumably mature granules may be preferentially released after GnRH stimulation.
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Affiliation(s)
- J L Crawford
- Human Reproductive Sciences Unit, Medical Research Council, University of Edinburgh Centre for Reproductive Biology, Edinburgh EH16 4SB, United Kingdom.
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Hosaka M, Suda M, Sakai Y, Izumi T, Watanabe T, Takeuchi T. Secretogranin III binds to cholesterol in the secretory granule membrane as an adapter for chromogranin A. J Biol Chem 2003; 279:3627-34. [PMID: 14597614 DOI: 10.1074/jbc.m310104200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Granin-family proteins, including chromogranin A (CgA) and secretogranin III (SgIII), are transported to secretory granules (SGs) in neuroendocrine cells. We previously showed that SgIII binds strongly to CgA in an intragranular milieu and targets CgA to SGs in pituitary and pancreatic endocrine cells. In this study, we demonstrated that with a sucrose density gradient of rat insulinoma-derived INS-1 cell homogenates, SgIII was localized to the SG fraction and was fractionated to the SG membrane (SGM) despite lacking the transmembrane region. With depletion of cholesterol from the SGM using methyl-beta-cyclodextrin, SgIII was impaired to bind to the SGM. Both SgIII and CgA were solubilized from the SGM by Triton X-100 in contrast to the Triton X-100 insolubility of carboxypeptidase E. SgIII and carboxypeptidase E strongly bound to the SGM-type liposome in intragranular conditions, but CgA did not. Instead, CgA bound to the SGM-type liposome only in the presence of SgIII. Immunocytochemical and pulse-chase experiments revealed that SgIII deleting the N-terminal lipid-binding region missorted to the constitutive pathway in mouse corticotroph-derived AtT-20 cells. Thus, we suggest that SgIII directly binds to cholesterol components of the SGM and targets CgA to SGs in pituitary and pancreatic endocrine cells.
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Affiliation(s)
- Masahiro Hosaka
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
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Huh YH, Jeon SH, Yoo SH. Chromogranin B-induced secretory granule biogenesis: comparison with the similar role of chromogranin A. J Biol Chem 2003; 278:40581-9. [PMID: 12902350 DOI: 10.1074/jbc.m304942200] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two major proteins of secretory granules of secretory cells, chromogranins A (CGA) and B (CGB), have previously been proposed to play key roles in secretory granule biogenesis. Recently, CGA was reported to play an on/off switch role for secretory granule biogenesis. In the present study we found CGB being more effective than CGA in inducing secretory granule formation in non-neuroendocrine NIH3T3 and COS-7 cells. The mean number of dense core granules formed/cell of CGA-transfected NIH3T3 cells was 2.51, whereas that of CGB-transfected cells was 4.02, indicating the formation of 60% more granules in the CGB-transfected cells. Similarly, there were 55% more dense core granules formed in the CGB-transfected COS-7 cells than in the CGA-transfected cells. Moreover, transfection of CGA- and CGB-short interfering RNA (siRNA) into neuroendocrine PC12 cells not only decreased the amount of CGA and CGB expressed but also reduced the number of secretory granules by 41 and 78%, respectively, further suggesting the importance of CGB expression in secretory granule formation.
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Affiliation(s)
- Yang Hoon Huh
- Department of Biochemistry, Inha University College of Medicine, Jung Gu, Incheon 400-712, Korea
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Montero-Hadjadje M, Pelletier G, Yon L, Li S, Guillemot J, Magoul R, Tillet Y, Vaudry H, Anouar Y. Biochemical characterization and immunocytochemical localization of EM66, a novel peptide derived from secretogranin II, in the rat pituitary and adrenal glands. J Histochem Cytochem 2003; 51:1083-95. [PMID: 12871990 DOI: 10.1177/002215540305100812] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Characterization of secretogranin II (SgII) mRNA in various vertebrates has revealed selective conservation of the amino acid sequences of two regions of the protein, i.e., the bioactive peptide secretoneurin and a flanking novel peptide that we named EM66. To help elucidate the possible role of EM66, we examined the occurrence as well as the cellular and subcellular distribution of EM66 in rat pituitary and adrenal glands by using a polyclonal antibody raised against the recombinant human EM66 peptide. High-performance liquid chromatography (HPLC) analysis of rat pituitary and adrenal extracts combined with a radioimmunoassay resolved EM66-immunoreactive material exhibiting the same retention time as recombinant EM66. In the rat pituitary, double-labeling immunohistochemical (IHC) studies showed that EM66 immunoreactivity (IR) was present in gonadotrophs, lactotrophs, thyrotrophs, and melanotrophs, whereas corticotrophs were devoid of labeling. EM66-IR was also observed in nerve endings in the neural lobe. Immunocytochemical staining at the electron microscopic level revealed that EM66-IR is sequestered in the secretory granules within gonadotrophs and lactotrophs. In the adrenal medulla, double IHC labeling showed that EM66-IR occurs exclusively in epinephrine-synthesizing cells. At the ultrastructural level, EM66-IR was seen in chromaffin vesicles of adrenomedullary cells. These results demonstrate that post-translational processing of SgII generates a novel peptide that exhibits a cell-specific distribution in the rat pituitary and adrenal glands where it is stored in secretory granules, supporting the notion that EM66 may play a role in the endocrine system.
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Affiliation(s)
- Maité Montero-Hadjadje
- European Institute for Peptide Research (IFRMP 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U413, UA CNRS, University of Rouen, Mont-Saint-Aignan, France
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Kim T, Tao-Cheng JH, Eiden LE, Loh YP. Large dense-core secretory granule biogenesis is under the control of chromogranin A in neuroendocrine cells. Ann N Y Acad Sci 2002; 971:323-31. [PMID: 12438143 DOI: 10.1111/j.1749-6632.2002.tb04487.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The large dense-core secretory granule is an organelle in neuroendocrine/endocrine cells, where prohormones and proneuropeptides are stored, processed, and secreted in a regulated manner. Here we present evidence that chromogranin A (CgA), one of the most abundant acidic glycoproteins ubiquitously present in neuroendocrine/endocrine cells, regulates dense-core secretory granule biogenesis. Specific depletion of CgA expression by antisense RNAs in PC12 cells led to a profound loss of secretory granule formation. An exogenously expressed prohormone, pro-opiomelanocortin, was neither stored nor secreted in a regulated manner in CgA-deficient PC12 cells. Overexpression of bovine CgA into CgA-deficient PC12 cells rescued regulated secretion. Other secretory granule proteins, such as chromogranin B (CgB), carboxypeptidase E, and synaptotagmin, were rapidly degraded, whereas nongranule proteins were not affected in CgA-deficient PC12 cells. Unlike CgA, another granin protein CgB could not substitute for the role of CgA in secretory granule biogenesis. Thus, we conclude that CgA is a master "on/off" switch regulating the formation of the dense-core secretory granule in neuroendocrine cells.
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Affiliation(s)
- Taeyoon Kim
- Section on Cellular Neurobiology, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Hosaka M, Watanabe T, Sakai Y, Uchiyama Y, Takeuchi T. Identification of a chromogranin A domain that mediates binding to secretogranin III and targeting to secretory granules in pituitary cells and pancreatic beta-cells. Mol Biol Cell 2002; 13:3388-99. [PMID: 12388744 PMCID: PMC129953 DOI: 10.1091/mbc.02-03-0040] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Chromogranin A (CgA) is transported restrictedly to secretory granules in neuroendocrine cells. In addition to pH- and Ca(2+)-dependent aggregation, CgA is known to bind to a number of vesicle matrix proteins. Because the binding-prone property of CgA with secretory proteins may be essential for its targeting to secretory granules, we screened its binding partner proteins using a yeast two-hybrid system. We found that CgA bound to secretogranin III (SgIII) by specific interaction both in vitro and in endocrine cells. Localization analysis showed that CgA and SgIII were coexpressed in pituitary and pancreatic endocrine cell lines, whereas SgIII was not expressed in the adrenal glands and PC12 cells. Immunoelectron microscopy demonstrated that CgA and SgIII were specifically colocalized in large secretory granules in male rat gonadotropes, which possess large-type and small-type granules. An immunocytochemical analysis revealed that deletion of the binding domain (CgA 48-111) for SgIII missorted CgA to the constitutive pathway, whereas deletion of the binding domain (SgIII 214-373) for CgA did not affect the sorting of SgIII to the secretory granules in AtT-20 cells. These findings suggest that CgA localizes with SgIII by specific binding in secretory granules in SgIII-expressing pituitary and pancreatic endocrine cells, whereas other mechanisms are likely to be responsible for CgA localization in secretory granules of SgIII-lacking adrenal chromaffin cells and PC12 cells.
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Affiliation(s)
- Masahiro Hosaka
- Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, 371-8512, Japan
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Kim T, Tao-Cheng JH, Eiden LE, Loh YP. Chromogranin A, an "on/off" switch controlling dense-core secretory granule biogenesis. Cell 2001; 106:499-509. [PMID: 11525735 DOI: 10.1016/s0092-8674(01)00459-7] [Citation(s) in RCA: 345] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present evidence that regulation of dense-core secretory granule biogenesis and hormone secretion in endocrine cells is dependent on chromogranin A (CGA). Downregulation of CGA expression in a neuroendocrine cell line, PC12, by antisense RNAs led to profound loss of dense-core secretory granules, impairment of regulated secretion of a transfected prohormone, and reduction of secretory granule proteins. Transfection of bovine CGA into a CGA-deficient PC12 clone rescued the regulated secretory phenotype. Stable transfection of CGA into a CGA-deficient pituitary cell line, 6T3, lacking a regulated secretory pathway, restored regulated secretion. Overexpression of CGA induced dense-core granules, immunoreactive for CGA, in nonendocrine fibroblast CV-1 cells. We conclude that CGA is an "on/off" switch that alone is sufficient to drive dense-core secretory granule biogenesis and hormone sequestration in endocrine cells.
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Affiliation(s)
- T Kim
- Section on Cellular Neurobiology, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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El Meskini R, Galano GJ, Marx R, Mains RE, Eipper BA. Targeting of membrane proteins to the regulated secretory pathway in anterior pituitary endocrine cells. J Biol Chem 2001; 276:3384-93. [PMID: 11060304 DOI: 10.1074/jbc.m008062200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Unlike the neuroendocrine cell lines widely used to study trafficking of soluble and membrane proteins to secretory granules, the endocrine cells of the anterior pituitary are highly specialized for the production of mature secretory granules. Therefore, we investigated the trafficking of three membrane proteins in primary anterior pituitary endocrine cells. Peptidylglycine alpha-amidating monooxygenase (PAM), an integral membrane protein essential to the production of many bioactive peptides, is cleaved and enters the regulated secretory pathway even when expressed at levels 40-fold higher than endogenous levels. Myc-TMD/CD, a membrane protein lacking the lumenal, catalytic domains of PAM, is still stored in granules. Secretory granules are not the default pathway for all membrane proteins, because Tac accumulates on the surface of pituitary endocrine cells. Overexpression of PAM is accompanied by a diminution in its endoproteolytic cleavage and in its BaCl(2)-stimulated release from mature granules. Because internalized PAM/PAM-antibody complexes are returned to secretory granules, the endocytic machinery of the pituitary endocrine cells is not saturated. As in corticotrope tumor cells, expression of PAM or Myc-TMD/CD alters the organization of the actin cytoskeleton. PAM-mediated alterations in the cytoskeleton may limit maturation of PAM and storage in mature granules.
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Affiliation(s)
- R El Meskini
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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