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Sander M, Wu Z, Strasburger CJ. Short stature explained by dimerization of human growth hormone induced by a p.C53S point mutation. J Biol Chem 2020; 295:4893-4901. [PMID: 32132170 DOI: 10.1074/jbc.ra119.009101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 02/29/2020] [Indexed: 11/06/2022] Open
Abstract
A homozygous mutation in growth hormone 1 (GH1) was recently identified in an individual with growth failure. This mutation, c.705G>C, causes replacement of cysteine at position 53 of the 191-amino-acid sequence of 22 kDa human GH (hGH) with serine (p.C53S). This hGH molecule (hereafter referred to as GH-C53S) lacks the disulfide bond between p.Cys-53 and p.Cys-165, which is highly conserved among species. It has been reported previously that monomeric GH-C53S has reduced bioactivity compared with WT GH (GH-WT) because of its decreased ability to bind and activate the GH receptor in vitro In this study, we discovered that substitution of p.Cys-53 in hGH significantly increased formation of hGH dimers in pituitary cells. We expressed His-tagged hGH variants in the cytoplasm of genetically modified Rosetta-gami B DE3 Escherichia coli cells, facilitating high-yield production. We observed that the bioactivity of monomeric GH-C53S is 25.2% of that of GH-WT and that dimeric GH-C53S-His has no significant bioactivity in cell proliferation assays. We also found that the expression of GH-C53S in pituitary cells deviates from that of GH-WT. GH-C53S was exclusively stained in the Golgi apparatus, and no secretory granules formed for this variant, impairing its stimulated release. In summary, the unpaired Cys-165 in GH-C53S forms a disulfide bond linking two hGH molecules in pituitary cells. We conclude that the GH-C53S dimer is inactive and responsible for the growth failure in the affected individual.
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Affiliation(s)
- Max Sander
- Department of Endocrinology, Diabetes, and Nutritional Medicine, Campus Charité Mitte, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Zida Wu
- Department of Endocrinology, Diabetes, and Nutritional Medicine, Campus Charité Mitte, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian J Strasburger
- Department of Endocrinology, Diabetes, and Nutritional Medicine, Campus Charité Mitte, Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
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Pech-Pool S, Berumen LC, Martínez-Moreno CG, García-Alcocer G, Carranza M, Luna M, Arámburo C. Thyrotropin-Releasing Hormone (TRH) and Somatostatin (SST), but not Growth Hormone-Releasing Hormone (GHRH) nor Ghrelin (GHRL), Regulate Expression and Release of Immune Growth Hormone (GH) from Chicken Bursal B-Lymphocyte Cultures. Int J Mol Sci 2020; 21:ijms21041436. [PMID: 32093298 PMCID: PMC7073104 DOI: 10.3390/ijms21041436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 12/31/2022] Open
Abstract
It is known that growth hormone (GH) is expressed in immune cells, where it exerts immunomodulatory effects. However, the mechanisms of expression and release of GH in the immune system remain unclear. We analyzed the effect of growth hormone-releasing hormone (GHRH), thyrotropin-releasing hormone (TRH), ghrelin (GHRL), and somatostatin (SST) upon GH mRNA expression, intracellular and released GH, Ser133-phosphorylation of CREB (pCREBS133), intracellular Ca2+ levels, as well as B-cell activating factor (BAFF) mRNA expression in bursal B-lymphocytes (BBLs) cell cultures since several GH secretagogues, as well as their corresponding receptors (-R), are expressed in B-lymphocytes of several species. The expression of TRH/TRH-R, ghrelin/GHS-R1a, and SST/SST-Rs (Subtypes 1 to 5) was observed in BBLs by RT-PCR and immunocytochemistry (ICC), whereas GHRH/GHRH-R were absent in these cells. We found that TRH treatment significantly increased local GH mRNA expression and CREB phosphorylation. Conversely, SST decreased GH mRNA expression. Additionally, when added together, SST prevented TRH-induced GH mRNA expression, but no changes were observed in pCREBS133 levels. Furthermore, TRH stimulated GH release to the culture media, while SST increased the intracellular content of this hormone. Interestingly, SST inhibited TRH-induced GH release in a dose-dependent manner. The coaddition of TRH and SST decreased the intracellular content of GH. After 10 min. of incubation with either TRH or SST, the intracellular calcium levels significantly decreased, but they were increased at 60 min. However, the combined treatment with both peptides maintained the Ca2+ levels reduced up to 60-min. of incubation. On the other hand, BAFF cytokine mRNA expression was significantly increased by TRH administration. Altogether, our results suggest that TRH and SST are implicated in the regulation of GH expression and release in BBL cultures, which also involve changes in pCREBS133 and intracellular Ca2+ concentration. It is likely that TRH, SST, and GH exert autocrine/paracrine immunomodulatory actions and participate in the maturation of chicken BBLs.
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Affiliation(s)
- Santiago Pech-Pool
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus Juriquilla, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico; (S.P.-P.); (M.C.)
- Posgrado en Ciencias Químico-Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico; (L.C.B.); (G.G.-A.)
| | - Laura C. Berumen
- Posgrado en Ciencias Químico-Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico; (L.C.B.); (G.G.-A.)
| | - Carlos G. Martínez-Moreno
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus Juriquilla, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico; (S.P.-P.); (M.C.)
| | - Guadalupe García-Alcocer
- Posgrado en Ciencias Químico-Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico; (L.C.B.); (G.G.-A.)
| | - Martha Carranza
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus Juriquilla, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico; (S.P.-P.); (M.C.)
| | - Maricela Luna
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus Juriquilla, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico; (S.P.-P.); (M.C.)
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro 76230, Mexico
- Correspondence: (M.L.); (C.A.); Tel.: +52-(55)-5623-4066 (M.L.); +52-(55)-5623-4065 (C.A.); Fax: +52-(55)-5623-4005 (M.L. & C.A.)
| | - Carlos Arámburo
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus Juriquilla, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico; (S.P.-P.); (M.C.)
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro 76230, Mexico
- Correspondence: (M.L.); (C.A.); Tel.: +52-(55)-5623-4066 (M.L.); +52-(55)-5623-4065 (C.A.); Fax: +52-(55)-5623-4005 (M.L. & C.A.)
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3
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Schernthaner-Reiter MH, Trivellin G, Stratakis CA. Chaperones, somatotroph tumors and the cyclic AMP (cAMP)-dependent protein kinase (PKA) pathway. Mol Cell Endocrinol 2020; 499:110607. [PMID: 31586652 DOI: 10.1016/j.mce.2019.110607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/28/2019] [Accepted: 09/30/2019] [Indexed: 02/08/2023]
Abstract
The cAMP-PKA pathway plays an essential role in the pituitary gland, governing cell differentiation and survival, and maintenance of endocrine function. Somatotroph growth hormone transcription and release as well as cell proliferation are regulated by the cAMP-PKA pathway; cAMP-PKA pathway abnormalities are frequently detected in sporadic as well as in hereditary somatotroph tumors and more rarely in other pituitary tumors. Inactivating variants of the aryl hydrocarbon receptor-interacting protein (AIP)-coding gene are the genetic cause of a subset of familial isolated pituitary adenomas (FIPA). Multiple functional links between the co-chaperone AIP and the cAMP-PKA pathway have been described. This review explores the role of chaperones including AIP in normal pituitary function as well as in somatotroph tumors, and their interaction with the cAMP-PKA pathway.
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Affiliation(s)
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA
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Bolamperti S, Guidobono F, Rubinacci A, Villa I. The Role of Growth Hormone in Mesenchymal Stem Cell Commitment. Int J Mol Sci 2019; 20:ijms20215264. [PMID: 31652811 PMCID: PMC6862273 DOI: 10.3390/ijms20215264] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/18/2019] [Accepted: 10/21/2019] [Indexed: 12/16/2022] Open
Abstract
Growth hormone (GH) is best known for its prominent role in promoting prepubertal growth and in regulating body composition and metabolism during adulthood. In recent years, the possible role of GH in the modulation of mesenchymal stem cell (MSC) commitment has gained interest. MSCs, characterized by active self-renewal and differentiation potential, express GH receptors. In MSCs derived from different adult tissues, GH induces an inhibition of adipogenic differentiation and favors MSC differentiation towards osteogenesis. This activity of GH indicates that regulation of body composition by GH has already started in the tissue progenitor cells. These findings have fostered research on possible uses of MSCs treated with GH in those pathologies, where a lack of or delays in bone repair occur. After an overview of GH activities, this review will focus on the research that has characterized GH’s effects on MSCs and on preliminary studies on the possible application of GH in bone regenerative medicine.
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Affiliation(s)
- Simona Bolamperti
- Bone Metabolism Unit, Division of Genetics & Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
| | - Francesca Guidobono
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy.
| | - Alessandro Rubinacci
- Bone Metabolism Unit, Division of Genetics & Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
| | - Isabella Villa
- Bone Metabolism Unit, Division of Genetics & Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
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Fridlyand LE, Tamarina NA, Schally AV, Philipson LH. Growth Hormone-Releasing Hormone in Diabetes. Front Endocrinol (Lausanne) 2016; 7:129. [PMID: 27777568 PMCID: PMC5056186 DOI: 10.3389/fendo.2016.00129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/06/2016] [Indexed: 12/13/2022] Open
Abstract
Growth hormone-releasing hormone (GHRH) is produced by the hypothalamus and stimulates growth hormone synthesis and release in the anterior pituitary gland. In addition, GHRH is an important regulator of cellular functions in many cells and organs. Expression of GHRH G-Protein Coupled Receptor (GHRHR) has been demonstrated in different peripheral tissues and cell types, including pancreatic islets. Among the peripheral activities, recent studies demonstrate a novel ability of GHRH analogs to increase and preserve insulin secretion by beta-cells in isolated pancreatic islets, which makes them potentially useful for diabetes treatment. This review considers the role of GHRHR in the beta-cell and addresses the unique engineered GHRH agonists and antagonists for treatment of type 2 diabetes mellitus. We discuss the similarity of signaling pathways activated by GHRHR in pituitary somatotrophs and in pancreatic beta-cells and possible ways as to how the GHRHR pathway can interact with glucose and other secretagogues to stimulate insulin secretion. We also consider the hypothesis that novel GHRHR agonists can improve glucose metabolism in Type 2 diabetes by preserving the function and survival of pancreatic beta-cells. Wound healing and cardioprotective action with new GHRH agonists suggest that they may prove useful in ameliorating certain diabetic complications. These findings highlight the future potential therapeutic effectiveness of modulators of GHRHR activity for the development of new therapeutic approaches in diabetes and its complications.
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Affiliation(s)
- Leonid E. Fridlyand
- Department of Medicine, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA
- *Correspondence: Leonid E. Fridlyand,
| | - Natalia A. Tamarina
- Department of Medicine, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA
| | - Andrew V. Schally
- VA Medical Center, Miami, FL, USA
- Department of Pathology and Medicine, Division of Endocrinology and Hematology-Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Louis H. Philipson
- Department of Medicine, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA
- Department of Pediatrics, The University of Chicago, Chicago, IL, USA
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Trivedi A, Babic S, Heiman M, Gibson WT, Chanoine JP. Acylated ghrelin is not required for the surge in pituitary growth hormone observed in pregnant mice. Peptides 2015; 65:29-33. [PMID: 25645493 DOI: 10.1016/j.peptides.2015.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/21/2015] [Accepted: 01/21/2015] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Ghrelin is produced by the stomach, hypothalamus and pituitary. It circulates as acylated ghrelin (AG, which stimulates growth hormone (GH) secretion) and unacylated ghrelin (UAG). Acylation is mediated by the enzyme ghrelin O-acyltransferase (GOAT). In mice, pregnancy is associated with a marked increase in circulating pituitary GH. We investigated the role of AG and UAG in the surge of plasma GH concentrations in pregnant mice at the end of pregnancy. DESIGN Using a mouse model generated on a C57BL/6 background (wild type, WT) in which the GOAT gene has been deleted (KO), we measured plasma AG, UAG and GH concentrations and tissue (stomach, pituitary and hypothalamus) preproghrelin and GOAT mRNA in non-pregnant (NP) and pregnant (P), WT and KO mice. RESULTS GOAT deletion was associated with undetectable concentrations of AG. UAG concentrations were similar in all groups. In both WT and KO animals, mean GH concentrations increased 30 to 50 times during pregnancy. There was a tendency toward lower median GH concentrations in KO (301 ng/mL) compared to WT (428 ng/mL) mice (p=0.059). Preproghrelin expression was not affected by GOAT deletion or by pregnancy in the stomach. In contrast, pituitary and hypothalamic ghrelin gene expression were lower in KO-NP and KO-P mice compared to their WT counterparts. CONCLUSION The complete absence of ghrelin acylation, which is associated with undetectable AG concentrations, does not prevent the marked increase in pituitary GH concentrations observed in pregnant mice, suggesting that AG is not the major mediator of GH secretion during pregnancy.
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Affiliation(s)
- Arjun Trivedi
- Child & Family Research Institute, Vancouver, BC, Canada V5Z 4H4; University of British Columbia, Vancouver, BC, Canada V6T 1Z4; BC Children's Hospital, Vancouver, BC, Canada V6H 3V4.
| | - Sandra Babic
- Child & Family Research Institute, Vancouver, BC, Canada V5Z 4H4
| | - Mark Heiman
- MicroBiome Therapeutics, Broomfield, CO 80021, USA
| | - William T Gibson
- Child & Family Research Institute, Vancouver, BC, Canada V5Z 4H4; University of British Columbia, Vancouver, BC, Canada V6T 1Z4; BC Children's Hospital, Vancouver, BC, Canada V6H 3V4
| | - Jean-Pierre Chanoine
- Child & Family Research Institute, Vancouver, BC, Canada V5Z 4H4; University of British Columbia, Vancouver, BC, Canada V6T 1Z4; BC Children's Hospital, Vancouver, BC, Canada V6H 3V4
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7
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Anderson LL. Insights into the Nanobiology of Growth Hormone Secretion. Discoveries (Craiova) 2014; 2:e22. [PMID: 32309551 PMCID: PMC6941573 DOI: 10.15190/d.2014.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The fact that partially empty vesicles are generated following cell secretion suggested that secretory vesicles do not collapse at the cell plasma membrane but, rather, transiently dock and fuse at the plasma membrane to expel a portion of their contents before retracting or undergoing endocytosis into the cell. Such a process has also been referred to in the literature as a "kiss-and-run" mechanism. This mechanism of cell secretion was conclusively demonstrated following the discovery of permanent cup-shaped lipoprotein structures at the cell plasma membrane, called "porosomes", where secretory vesicles transiently dock and fuse to expel intravesicular contents from the cell. Porosomes are present in all secretory cells, from the digestive enzyme-secreting pancreatic acinar cells, to the hormone-releasing growth hormone cells, mast cells, chromaffin cells, hair cells of the inner ear, to neurons secreting neurotransmitters. Hence, it can be asserted that porosomes are the universal secretory machinery in the plasma membrane of secretory cells. Therefore, the discovery of the porosome has resulted in a paradigm shift in our understanding of cell secretion. Rapid transport of secretory vesicles containing hormones to the plasma membrane is powered by high-energy molecules such as ATP, GTP or NADH. Immunogold labeled transmission electron microscopy (TEM) was used to determine the total number of secretory vesicles in resting and in GH-stimulated porcine pituitary cells. We identified three categories of vesicles: filled, empty, and partly empty. Resting GH cells contained more than twice as many filled vesicles than did the stimulated ones. However, stimulated cells contained nearly twice as many empty vesicles and 2.5 times more partly empty vesicles than did resting cells. Secretory vesicles in GH cells further revealed the localization of GH only in electron dense vesicles in both resting and stimulated cells. No change in the total number of secretory vesicles following secretion was observed. These results are consistent with a mechanism that, after stimulation of secretion, vesicles transiently dock and fuse at the porosome to establish a fusion pore, through which intravesicular contents are released.
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Affiliation(s)
- Lloyd L Anderson
- Department of Animal Science, College of Agriculture and Life Sciences and Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011-3150 USA
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Meng F, Huang G, Gao S, Li J, Yan Z, Wang Y. Identification of the receptors for somatostatin (SST) and cortistatin (CST) in chickens and investigation of the roles of cSST28, cSST14, and cCST14 in inhibiting cGHRH1-27NH2-induced growth hormone secretion in cultured chicken pituitary cells. Mol Cell Endocrinol 2014; 384:83-95. [PMID: 24418361 DOI: 10.1016/j.mce.2014.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 12/15/2013] [Accepted: 01/06/2014] [Indexed: 01/13/2023]
Abstract
Somatostatin receptors (SSTRs) are proposed to mediate the actions of somatostatin (SST) and its related peptide, cortistatin (CST), in vertebrates. However, the identity, functionality, and tissue expression of these receptors remain largely unknown in most non-mammalian vertebrates including birds. In this study, five SSTRs (named cSSTR1, cSSTR2, cSSTR3, cSSTR4, cSSTR5) were cloned from chicken brain by RT-PCR. Using a pGL3-CRE-luciferase reporter system, we demonstrated that activation of each cSSTR expressed in CHO cells by cSST28, cSST14 and cCST14 treatment could inhibit forskolin-induced luciferase activity of CHO cells, indicating the functional coupling of all cSSTRs to Gi protein(s). Interestingly, cSSTR1-4 expressed in CHO cells could be activated by cSST28, cSST14 and cCST14 with high potencies, suggesting that they may function as the receptors common for these peptides. In contrast, cSSTR5 could be potently activated by cSST28 only, indicating that it is a cSST28-specific receptor. Using RT-PCR, wide expression of cSSTRs was detected in chicken tissues including pituitary. In accordance with their expression in pituitary, cSST28, cSST14, and cCST14 were demonstrated to inhibit basal and novel cGHRH1-27NH2-induced GH secretion in cultured chicken pituitary cells dose-dependently (0-10nM) by Western blot analysis, suggesting the involvement of cSSTR(s) common for these peptides in mediating their inhibitory actions. Collectively, our study establishes a molecular basis to elucidate the roles of SST/CST in birds and provide insights into the roles of SST/CST in vertebrates, such as their conserved actions on pituitary.
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Affiliation(s)
- Fengyan Meng
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Guian Huang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Shunyu Gao
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Juan Li
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Zhenxin Yan
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China
| | - Yajun Wang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
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Carmean CM, Cohen RN, Brady MJ. Systemic regulation of adipose metabolism. Biochim Biophys Acta Mol Basis Dis 2014; 1842:424-30. [DOI: 10.1016/j.bbadis.2013.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 05/15/2013] [Accepted: 06/01/2013] [Indexed: 12/11/2022]
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Delporte C. Structure and physiological actions of ghrelin. SCIENTIFICA 2013; 2013:518909. [PMID: 24381790 PMCID: PMC3863518 DOI: 10.1155/2013/518909] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 11/10/2013] [Indexed: 05/30/2023]
Abstract
Ghrelin is a gastric peptide hormone, discovered as being the endogenous ligand of growth hormone secretagogue receptor. Ghrelin is a 28 amino acid peptide presenting a unique n-octanoylation modification on its serine in position 3, catalyzed by ghrelin O-acyl transferase. Ghrelin is mainly produced by a subset of stomach cells and also by the hypothalamus, the pituitary, and other tissues. Transcriptional, translational, and posttranslational processes generate ghrelin and ghrelin-related peptides. Homo- and heterodimers of growth hormone secretagogue receptor, and as yet unidentified receptors, are assumed to mediate the biological effects of acyl ghrelin and desacyl ghrelin, respectively. Ghrelin exerts wide physiological actions throughout the body, including growth hormone secretion, appetite and food intake, gastric secretion and gastrointestinal motility, glucose homeostasis, cardiovascular functions, anti-inflammatory functions, reproductive functions, and bone formation. This review focuses on presenting the current understanding of ghrelin and growth hormone secretagogue receptor biology, as well as the main physiological effects of ghrelin.
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Affiliation(s)
- Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, 808 Route de Lennik, Bat G/E-CP611, 1070 Brussels, Belgium
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Kovari LC, Brunzelle JS, Lewis KT, Cho WJ, Lee JS, Taatjes DJ, Jena BP. X-ray solution structure of the native neuronal porosome-synaptic vesicle complex: Implication in neurotransmitter release. Micron 2013; 56:37-43. [PMID: 24176623 DOI: 10.1016/j.micron.2013.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 09/29/2013] [Accepted: 10/02/2013] [Indexed: 11/30/2022]
Abstract
Nanoportals at the cell plasma membrane called porosomes, mediate secretion from cells. In neurons porosomes are 15 nm cup-shaped lipoprotein structure composed of nearly 40 proteins. The size and complexity of the porosome has precluded determination of its atomic structure. Here we report at nanometer resolution the native 3D structure of the neuronal porosome-synaptic vesicle complex within isolated nerve terminals using small-angle X-ray solution scattering. In addition to furthering our understanding of the porosome structure, results from the study suggests the molecular mechanism involved in neurotransmitter release at the nerve terminal.
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Affiliation(s)
- Ladislau C Kovari
- Wayne State University School of Medicine, Department of Biochemistry and Molecular Biology, Detroit, MI, USA
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Differential effects of glycogen synthase kinase 3 (GSK3) inhibition by lithium or selective inhibitors in the central nervous system. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:893-903. [DOI: 10.1007/s00210-013-0893-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/04/2013] [Indexed: 12/17/2022]
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13
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Lepper A, Frese A, Summ O, Nofer JR, Evers S. Hypothalamic dopaminergic stimulation in cluster headache. Cephalalgia 2013; 33:1155-9. [PMID: 23630400 DOI: 10.1177/0333102413487445] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Cluster headache is associated with structural abnormalities of the hypothalamus. We were interested in the association of cluster headache with endocrinological functional abnormalities. Therefore, we applied the apomorphine challenge test, which is a specific test of hypothalamic dopaminergic activation. METHODS We enrolled 13 patients with cluster headache outside the bout and without medication. They were stimulated with 0.005 mg/kg of body weight subcutaneous apomorphine hydrochloride. After 45 and 60 minutes, growth hormone (GH), prolactin and cortisol were measured. The test was also applied to 14 sex- and age-matched healthy control subjects. RESULTS There were significantly higher GH levels in healthy subjects as compared to cluster headache patients 45 minutes after injection (10.8 ± 10.8 versus 4.4 ± 7.4 ng/ml; P = 0.038). Only in cluster headache, the GH level after 60 minutes was not significantly different from the baseline. The levels of prolactin and cortisol did not show any significant differences between cluster headache patients and in healthy subjects. DISCUSSION Our data suggest that cluster headache is associated with an impaired dopaminergic stimulation. This finding supports the body of evidence that cluster headache is associated with a functional abnormality of the hypothalamus and that this association is a primary (i.e. idiopathic) and not a secondary phenomenon during the bout.
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Affiliation(s)
- Anne Lepper
- Department of Neurology, University of Münster, Germany
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