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Iwakura H, Ensho T, Ueda Y. Desacyl-ghrelin, not just an inactive form of ghrelin?-A review of current knowledge on the biological actions of desacyl-ghrelin. Peptides 2023:171050. [PMID: 37392995 DOI: 10.1016/j.peptides.2023.171050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023]
Abstract
Desacyl-ghrelin is a form of ghrelin which lacks acyl-modification of the third serine residue of ghrelin. Originally, desacyl-ghrelin was considered to be just an inactive form of ghrelin. More recently, however, it has been suggested to have various biological activities, including control of food intake, growth hormone, glucose metabolism, and gastric movement, and is involved in cell survival. In this review, we summarize the current knowledge of the biological actions of desacyl-ghrelin and the proposed mechanisms by which it exerts the effects.
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Affiliation(s)
- Hiroshi Iwakura
- Department of Pharmacotherapeutics, School of Pharmaceutical Science, Wakayama Medical University, 25-1 Shichibancho, Wakayama 640-8156, Japan.
| | - Takuya Ensho
- Department of Pharmacotherapeutics, School of Pharmaceutical Science, Wakayama Medical University, 25-1 Shichibancho, Wakayama 640-8156, Japan
| | - Yoko Ueda
- Department of Pharmacotherapeutics, School of Pharmaceutical Science, Wakayama Medical University, 25-1 Shichibancho, Wakayama 640-8156, Japan
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2
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Komarowska H, Rucinski M, Tyczewska M, Sawicka-Gutaj N, Szyszka M, Hernik A, Klimont A, Milecka P, Migasiuk L, Biczysko M, Idasiak-Piechocka I, Karczewski M, Ruchala M. Ghrelin as a potential molecular marker of adrenal carcinogenesis: In vivo and in vitro evidence. Clin Endocrinol (Oxf) 2018; 89:36-45. [PMID: 29682767 DOI: 10.1111/cen.13725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 04/16/2018] [Accepted: 04/18/2018] [Indexed: 12/30/2022]
Abstract
CONTEXT Adrenal tumours belong to one of the most prevalent neoplasms. It is a heterogeneous group with different aetiology, clinical manifestation and prognosis. Its histopathologic diagnosis is difficult and identification of differentiation markers for tumorigenesis is extremely valuable for diagnosis. DESIGN To assess ghrelin expression and the relationship among ghrelin, IGF2 and the clinicopathological characteristics of adrenal tumours. To investigate the influence of ghrelin on ACC cell line proliferation. MATERIALS AND METHODS Expression of ghrelin and IGF2 in a total of 84 adrenal tissue samples (30 adenoma, 12 hyperplasia, 8 myelolipoma, 20 pheochromocytoma, 7 carcinoma and 7 unchanged adrenal glands) were estimated. Every operated patient from whom samples were obtained underwent clinicopathological analysis. All the parameters were compared among the groups examined and correlations between these were estimated. H295R cell line was incubated with ghrelin to assess its effect on proliferation and migration rate. RESULTS The highest ghrelin expression was observed in carcinoma samples and the lowest in the control group. Ghrelin expression was 21 times higher in carcinoma (P = .017) and 2.4 times higher in adenoma (P = .029) compared with controls. There were no statistically significant differences between myelolipoma (P = .093) and pheochromocytoma (P = .204) relative to the control. Ghrelin level was significantly higher in carcinoma compared to adenoma (P = .049) samples. A positive correlation between ghrelin and IGF2 expression was observed only in myelolipoma (P = .001). Ghrelin at concentrations of 1 × 10-6 mol/L and 1 × 10-8 mol/L significantly stimulated proliferation and migration rate in the H295R cell line. CONCLUSION Ghrelin appears to be an essential factor in driving adrenal tumours development.
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Affiliation(s)
- Hanna Komarowska
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | - Marcin Rucinski
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan, Poland
| | - Marianna Tyczewska
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan, Poland
| | - Nadia Sawicka-Gutaj
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | - Marta Szyszka
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan, Poland
| | - Aleksandra Hernik
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | - Anna Klimont
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | - Paulina Milecka
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan, Poland
| | - Laura Migasiuk
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | - Mateusz Biczysko
- Department of General, Endocrinological and Gastroenterological Surgery, Poznan University of Medical Sciences, Poznan, Poland
| | - Ilona Idasiak-Piechocka
- Department of Nephrology, Transplantology and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
| | - Marek Karczewski
- Department of General and Transplantation Surgery, Poznan University of Medical Sciences, Poznan, Poland
| | - Marek Ruchala
- Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland
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Ucan B, Sahin M, Kizilgul M, Ozbek M, Ozdemir S, Calıskan M, Cakal E. Serum ghrelin levels in papillary thyroid carcinoma. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2017; 61:464-469. [PMID: 28977162 PMCID: PMC10522255 DOI: 10.1590/2359-3997000000290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 05/15/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Ghrelin plays a role in several processes of cancer progression, and numerous cancer types express ghrelin and its receptor. We aimed to investigate serum levels of ghrelin in patients with papillary thyroid carcinoma (PTC) and its association with the prognostic factors in PTC. MATERIALS AND METHODS We enrolled 54 patients with thyroid cancer (7 male, 47 female) and 24 healthy controls (6 male, 18 female) in the study. We compared demographic, anthropometric, and biochemical data, and serum ghrelin levels between the groups. Serum ghrelin levels were measured using as enzyme-linked immunosorbent assay. RESULTS Ghrelin levels were similar between the groups, but plasma ghrelin levels were significantly higher in tumors larger than 1 cm diameter compared with papillary microcarcinomas. Serum ghrelin levels also correlated with tumor size (r = 0.499; p < 0.001). Body mass index, thyroid-stimulating hormone, and HOMA-IR levels were similar between the groups. There were no statistically significant differences regarding average age and other prognostic parameters including lymph node invasion, capsule invasion, multifocality and surgical border invasion between patients with microcarcinoma and tumors larger than 1 cm. CONCLUSION In our study, no significant difference in serum ghrelin levels was determined between patients with papillary thyroid cancer and healthy controls however, serum ghrelin levels were higher in tumors larger than 1 cm compared to in those with thyroid papillary microcarcinoma.
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Affiliation(s)
- Bekir Ucan
- SBU Diskapi Yildirim Beyazit Training and Research HospitalDepartment of Endocrinology and MetabolismAnkaraTurkeySBU Diskapi Yildirim Beyazit Training and Research Hospital, Department of Endocrinology and Metabolism, Ankara, Turkey
| | - Mustafa Sahin
- Ankara UniversitySchool of MedicineDepartment of Endocrinology and MetabolismAnkaraTurkeyAnkara University, School of Medicine, Department of Endocrinology and Metabolism, Ankara, Turkey
| | - Muhammed Kizilgul
- SBU Diskapi Yildirim Beyazit Training and Research HospitalDepartment of Endocrinology and MetabolismAnkaraTurkeySBU Diskapi Yildirim Beyazit Training and Research Hospital, Department of Endocrinology and Metabolism, Ankara, Turkey
| | - Mustafa Ozbek
- SBU Diskapi Yildirim Beyazit Training and Research HospitalDepartment of Endocrinology and MetabolismAnkaraTurkeySBU Diskapi Yildirim Beyazit Training and Research Hospital, Department of Endocrinology and Metabolism, Ankara, Turkey
| | - Seyda Ozdemir
- SBU Diskapi Yildirim Beyazit Training and Research HospitalDepartment of BiochemistryAnkaraTurkeySBU Diskapi Yildirim Beyazit Training and Research Hospital, Department of Biochemistry, Ankara, Turkey
| | - Mustafa Calıskan
- SBU Diskapi Yildirim Beyazit Training and Research HospitalDepartment of Endocrinology and MetabolismAnkaraTurkeySBU Diskapi Yildirim Beyazit Training and Research Hospital, Department of Endocrinology and Metabolism, Ankara, Turkey
| | - Erman Cakal
- SBU Diskapi Yildirim Beyazit Training and Research HospitalDepartment of Endocrinology and MetabolismAnkaraTurkeySBU Diskapi Yildirim Beyazit Training and Research Hospital, Department of Endocrinology and Metabolism, Ankara, Turkey
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Ghrelin and cancer progression. Biochim Biophys Acta Rev Cancer 2017; 1868:51-57. [PMID: 28238732 DOI: 10.1016/j.bbcan.2017.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/27/2017] [Accepted: 02/18/2017] [Indexed: 12/22/2022]
Abstract
Ghrelin is a small peptide with 28 amino acids, and has been characterized as the ligand of the growth hormone secretagogue receptor (GHSR). In addition to its original function in stimulating pituitary growth hormone release, ghrelin is multifunctional and plays a role in the regulation of energy balance, gastric acid release, appetite, insulin secretion, gastric motility and the turnover of gastric and intestinal mucosa. The discovery of ghrelin and GHSR expression beyond normal tissues suggests its role other than physiological function. Emerging evidences have revealed ghrelin's function in regulating several processes related to cancer progression, especially in metastasis and proliferation. We further show the relative GHRL and GHSR expression in pan-cancers from The Cancer Genome Atlas (TCGA), suggesting the potential pathological role of the axis in cancers. This review focuses on ghrelin's biological function in cancer progression, and reveals its clinical significance especially the impact on cancer patient outcome.
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The Influence of Ghrelin on the Development of Dextran Sodium Sulfate-Induced Colitis in Rats. BIOMED RESEARCH INTERNATIONAL 2015; 2015:718314. [PMID: 26713317 PMCID: PMC4680107 DOI: 10.1155/2015/718314] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/10/2015] [Accepted: 11/16/2015] [Indexed: 01/24/2023]
Abstract
Ghrelin has protective and therapeutic effects in the gut. The aim of present studies was to investigate the effect of treatment with ghrelin on the development of colitis evoked by dextran sodium sulfate (DSS). Methods. Studies have been performed on rats. Colitis was induced by adding 5% DSS to the drinking water for 5 days. During this period animals were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 8 nmol/kg/dose. On the sixth day, animals were anesthetized and the severity of colitis was assessed. Results. Treatment with ghrelin during administration of DSS reduced the development of colitis. Morphological features of colonic mucosa exhibited a reduction in the area and deep of mucosal damage. Ghrelin reversed the colitis-induced decrease in blood flow, DNA synthesis, and superoxide dismutase activity in colonic mucosa. These effects were accompanied by a decrease in the colitis-evoked increase in mucosal concentration of interleukin-1β and malondialdehyde. Treatment with ghrelin reversed the DSS-induced reduction in body weight gain. Conclusions. Administration of ghrelin exhibits the preventive effect against the development of DSS-induced colitis. This effect seems to be related to ghrelin's anti-inflammatory and antioxidative properties.
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Zhang B, Liu Y, Zhang JS, Zhang XH, Chen WJ, Yin XH, Qi YF. Cortistatin protects myocardium from endoplasmic reticulum stress induced apoptosis during sepsis. Mol Cell Endocrinol 2015; 406:40-8. [PMID: 25727193 DOI: 10.1016/j.mce.2015.02.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 02/14/2015] [Accepted: 02/16/2015] [Indexed: 10/23/2022]
Abstract
Sepsis and septic shock are common entities encountered in intensive care units. Myocardial depression is a well-recognized manifestation of organ dysfunction in sepsis, and myocardial apoptosis is a key step for this progression, which may contribute to cardiac contractile dysfunction. Increasing evidence suggested the anti-inflammatory role of cortistatin (CST) during lethal endotoxemia. However, the direct protective effect of CST on myocardial is still not clear. Here, we aimed to study whether CST can directly protect myocardial from apoptosis. To test that, we used cecal ligation and puncture (CLP) induced sepsis rat model. CST (175 µg/kg, intraperitoneal administration) was injected every 24 h before the model induction for 3 days. Electron microscopy, TUNEL staining, caspase-3 expression, and the Bcl-2/Bax ratio were used to measure myocardial apoptosis. In addition, the protein levels of endoplasmic reticulum stress (ERS) markers were overexpressed in sepsis. To further test whether CST can directly protect myocardial apoptosis from ERS, we compared dithiothreitol (DTT) induced cardiomyocyte (CM) ERS with or without CST in vitro. We found that CST strongly attenuated lipopolysaccharide (LPS) and DTT induced CM ERS. Blocking GHS-R1a, one of CST's receptors expressed by CMs, completely abrogated CST's protective effect. Finally, CST's protective effect was associated with the decrease of ERS both in vivo and in vitro. In conclusion, our results for the first time showed the previously unexpected role of CST to directly protect myocardial from apoptosis through inhibiting ERS and partly through GHS-R1a.
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Affiliation(s)
- Bo Zhang
- Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Yue Liu
- Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Jin-Sheng Zhang
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - Xiao-Hui Zhang
- Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Wen-Jia Chen
- Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Xin-Hua Yin
- Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin 150001, China.
| | - Yong-Fen Qi
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University Health Science Center, Beijing 100191, China; Laboratory of Cardiovascular Bioactive Molecule, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
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Khatib MN, Gaidhane S, Gaidhane AM, Simkhada P, Zahiruddin QS. Ghrelin O Acyl Transferase (GOAT) as a Novel Metabolic Regulatory Enzyme. J Clin Diagn Res 2015; 9:LE01-5. [PMID: 25859472 PMCID: PMC4378754 DOI: 10.7860/jcdr/2015/9787.5514] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 12/06/2014] [Indexed: 01/12/2023]
Abstract
BACKGROUND Obesity and Type 2 Diabetes Mellitus (T2DM) presents a growing threat to the global health. Evidences highlight an important role of ghrelin as a key regulator of glucose metabolism. The physiological functions of ghrelin are mediated by enzyme ghrelin-O-acyltransferase (GOAT) which is capable of generating the active form of this metabolic hormone. However, its exact mechanism of action and influence on energy balance and glucose metabolism is yet to be explored. OBJECTIVES To review the physiological role of GOAT in the regulation of energy balance and glucose metabolism and explore the potential therapeutic avenues of modulators of GOAT to counter the progression of obesity and T2DM. METHODS Publications were sought through electronic searches. The bibliographies of all papers, book, chapters and editorials were scanned and hand searches were also conducted for journals, and conference proceedings. CONCLUSION GOAT peptide modulates the insulin secretion as well as insulin sensitivity. Modulators of GOAT signaling like inhibitors of GOAT increases insulin secretion, enhance peripheral insulin sensitivity and thus counters obesity and T2DM. Modulators of GOAT can be a probable therapy for modifying food intake and for countering obesity and T2DM.
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Affiliation(s)
- Mahalaqua Nazli Khatib
- Professor, Department of Physiology, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Shilpa Gaidhane
- Associate Professor, Department of Medicine, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Abhay M. Gaidhane
- Professor, Department of Community Medicine, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Padam Simkhada
- Senior Lecturer in International Health ScHARR, University of Sheffield, UK and Centre for public Health Liverpool Johns Moores University, Liverpool, UK
| | - Quazi Syed Zahiruddin
- Professor, Department of Community Medicine, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
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Angelino E, Reano S, Ferrara M, Agosti E, Graziani A, Filigheddu N. Antifibrotic activity of acylated and unacylated ghrelin. Int J Endocrinol 2015; 2015:385682. [PMID: 25960743 PMCID: PMC4415458 DOI: 10.1155/2015/385682] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/01/2015] [Indexed: 12/15/2022] Open
Abstract
Fibrosis can affect almost all tissues and organs, it often represents the terminal stage of chronic diseases, and it is regarded as a major health issue for which efficient therapies are needed. Tissue injury, by inducing necrosis/apoptosis, triggers inflammatory response that, in turn, promotes fibroblast activation and pathological deposition of extracellular matrix. Acylated and unacylated ghrelin are the main products of the ghrelin gene. The acylated form, through its receptor GHSR-1a, stimulates appetite and growth hormone (GH) release. Although unacylated ghrelin does not bind or activate GHSR-1a, it shares with the acylated form several biological activities. Ghrelin peptides exhibit anti-inflammatory, antioxidative, and antiapoptotic activities, suggesting that they might represent an efficient approach to prevent or reduce fibrosis. The aim of this review is to summarize the available evidence regarding the effects of acylated and unacylated ghrelin on different pathologies and experimental models in which fibrosis is a predominant characteristic.
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Affiliation(s)
- Elia Angelino
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Simone Reano
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Michele Ferrara
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Emanuela Agosti
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Andrea Graziani
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Nicoletta Filigheddu
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
- *Nicoletta Filigheddu:
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Callaghan B, Kosari S, Pustovit RV, Sartor DM, Ferens D, Ban K, Baell J, Nguyen TV, Rivera LR, Brock JA, Furness JB. Hypotensive effects of ghrelin receptor agonists mediated through a novel receptor. Br J Pharmacol 2014; 171:1275-86. [PMID: 24670149 DOI: 10.1111/bph.12527] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 09/27/2013] [Accepted: 11/12/2013] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Some agonists of ghrelin receptors cause rapid decreases in BP. The mechanisms by which they cause hypotension and the pharmacology of the receptors are unknown. EXPERIMENTAL APPROACH The effects of ligands of ghrelin receptors were investigated in rats in vivo, on isolated blood vessels and on cells transfected with the only molecularly defined ghrelin receptor, growth hormone secretagogue receptor 1a (GHSR1a). KEY RESULTS Three agonists of GHSR1a receptors, ulimorelin, capromorelin and CP464709, caused a rapid decrease in BP in the anaesthetized rat. The effect was not reduced by either of two GHSR1a antagonists, JMV2959 or YIL781, at doses that blocked effects on colorectal motility, in vivo. The rapid hypotension was not mimicked by ghrelin, unacylated ghrelin or the unacylated ghrelin receptor agonist, AZP531. The early hypotension preceded a decrease in sympathetic nerve activity. Early hypotension was not reduced by hexamethonium or by baroreceptor (sino-aortic) denervation. Ulimorelin also relaxed isolated segments of rat mesenteric artery, and, less potently, relaxed aorta segments. The vascular relaxation was not reduced by JMV2959 or YIL781. Ulimorelin, capromorelin and CP464709 activated GHSR1a in transfected HEK293 cells at nanomolar concentrations. JMV2959 and YIL781 both antagonized effects in these cells, with their pA2 values at the GHSR1a receptor being 6.55 and 7.84. CONCLUSIONS AND IMPLICATIONS Our results indicate a novel vascular receptor or receptors whose activation by ulimorelin, capromorelin and CP464709 lowered BP. This receptor is activated by low MW GHSR1a agonists, but is not activated by ghrelin.
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Affiliation(s)
- Brid Callaghan
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Vic., Australia
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Kaščáková S, Hofland LJ, De Bruijn HS, Ye Y, Achilefu S, van der Wansem K, van der Ploeg-van den Heuvel A, van Koetsveld PM, Brugts MP, van der Lelij AJ, Sterenborg HJCM, ten Hagen TLM, Robinson DJ, van Hagen MP. Somatostatin analogues for receptor targeted photodynamic therapy. PLoS One 2014; 9:e104448. [PMID: 25111655 PMCID: PMC4128677 DOI: 10.1371/journal.pone.0104448] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 07/08/2014] [Indexed: 12/15/2022] Open
Abstract
Photodynamic therapy (PDT) is an established treatment modality, used mainly for anticancer therapy that relies on the interaction of photosensitizer, light and oxygen. For the treatment of pathologies in certain anatomical sites, improved targeting of the photosensitizer is necessary to prevent damage to healthy tissue. We report on a novel dual approach of targeted PDT (vascular and cellular targeting) utilizing the expression of neuropeptide somatostatin receptor (sst2) on tumor and neovascular-endothelial cells. We synthesized two conjugates containing the somatostatin analogue [Tyr3]-octreotate and Chlorin e6 (Ce6): Ce6-K3-[Tyr3]-octreotate (1) and Ce6-[Tyr3]-octreotate-K3-[Tyr3]-octreotate (2). Investigation of the uptake and photodynamic activity of conjugates in-vitro in human erythroleukemic K562 cells showed that conjugation of [Tyr3]-octreotate with Ce6 in conjugate 1 enhances uptake (by a factor 2) in cells over-expressing sst2 compared to wild-type cells. Co-treatment with excess free Octreotide abrogated the phototoxicity of conjugate 1 indicative of a specific sst2-mediated effect. In contrast conjugate 2 showed no receptor-mediated effect due to its high hydrophobicity. When compared with un-conjugated Ce6, the PDT activity of conjugate 1 was lower. However, it showed higher photostability which may compensate for its lower phototoxicity. Intra-vital fluorescence pharmacokinetic studies of conjugate 1 in rat skin-fold observation chambers transplanted with sst2+ AR42J acinar pancreas tumors showed significantly different uptake profiles compared to free Ce6. Co-treatment with free Octreotide significantly reduced conjugate uptake in tumor tissue (by a factor 4) as well as in the chamber neo-vasculature. These results show that conjugate 1 might have potential as an in-vivo sst2 targeting photosensitizer conjugate.
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Affiliation(s)
- Slávka Kaščáková
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
| | - Leo J. Hofland
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Henriette S. De Bruijn
- Department of Otolaryngology and Head & Neck Surgery, Erasmus MC, Rotterdam, The Netherlands
| | - Yunpeng Ye
- Department of Radiology, School of Medicine, Washington University, St. Louis, Missouri, United States of America
| | - Samuel Achilefu
- Department of Radiology, School of Medicine, Washington University, St. Louis, Missouri, United States of America
| | | | | | | | - Michael P. Brugts
- Department of Immunology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Henricus J. C. M. Sterenborg
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands
| | - Timo L. M. ten Hagen
- Department of Surgical Oncology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Dominic J. Robinson
- Department of Otolaryngology and Head & Neck Surgery, Erasmus MC, Rotterdam, The Netherlands
| | - Martin P. van Hagen
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Immunology, Erasmus Medical Center, Rotterdam, The Netherlands
- * E-mail:
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Mirzaie Bavil F, Mohaddes G, Ebrahimi H, Keyhanmanesh R, Ghiyasi R, Alipour MR. Ghrelin increases lymphocytes in chronic normobaric hypoxia. Adv Pharm Bull 2014; 4:339-43. [PMID: 25436188 DOI: 10.5681/apb.2014.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 03/17/2014] [Accepted: 04/05/2014] [Indexed: 12/26/2022] Open
Abstract
PURPOSE Hypoxia is a condition of decreased availability of oxygen. To adapt hypoxia, some changes in blood cells occur in the body. The aim of this study was to evaluate the effect of ghrelin on different types of blood cell in normobaric hypoxia situation. METHODS Thirty-two animals were divided in 4 groups (n=8): control (C), ghrelin (G), hypoxia (H), and hypoxic animals that received ghrelin (H+G). Hypoxia (11%) was induced by an Environmental Chamber System GO2 Altitude. Animals in ghrelin groups received a subcutaneous injection of ghrelin (150 μg/kg/day) for 14 days. RESULTS Our results show that ghrelin significantly (p<0.05) increased RBC and Hct levels, whereas it significantly (p<0.05) decreased lymphocytes in the blood. RBC, Hct, Hb concentration, platelet and MCV increased significantly (p<0.05) in hypoxic conditions but lymphocytes, monocytes and Polymorphonuclears did not show any significant changes. Platelets had a significant (p<0.05) decrease in hypoxic conditions and ghrelin administration in hypoxic conditions could increase lymphocyte levels significantly (p<0.05). CONCLUSION Effect of ghrelin on blood cells could be related to blood oxygen level. Ghrelin in normal oxygen conditions increases RBC and Hct levels but decreases lymphocytes, whereas in hypoxic conditions, ghrelin increases blood lymphocytes.
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Affiliation(s)
- Fariba Mirzaie Bavil
- Tuberculosis and Lung Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Gisou Mohaddes
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hadi Ebrahimi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Rana Keyhanmanesh
- Tuberculosis and Lung Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Rafigheh Ghiyasi
- Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Reza Alipour
- Tuberculosis and Lung Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Prodam F, Filigheddu N. Ghrelin gene products in acute and chronic inflammation. Arch Immunol Ther Exp (Warsz) 2014; 62:369-84. [PMID: 24728531 DOI: 10.1007/s00005-014-0287-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/21/2014] [Indexed: 12/27/2022]
Abstract
Ghrelin gene products--the peptides ghrelin, unacylated ghrelin, and obestatin--have several actions on the immune system, opening new perspectives within neuroendocrinology, metabolism and inflammation. The aim of this review is to summarize the available evidence regarding the less known role of these peptides in the machinery of inflammation and autoimmunity, outlining some of their most promising therapeutic applications.
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Affiliation(s)
- Flavia Prodam
- Departmant of Health Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
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13
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Pei XM, Yung BY, Yip SP, Ying M, Benzie IF, Siu PM. Desacyl ghrelin prevents doxorubicin-induced myocardial fibrosis and apoptosis via the GHSR-independent pathway. Am J Physiol Endocrinol Metab 2014; 306:E311-23. [PMID: 24326424 DOI: 10.1152/ajpendo.00123.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Doxorubicin is an effective chemotherapeutic agent used to treat malignancies, but it causes cardiomyopathy. Preliminary evidence suggests that desacyl ghrelin might have protective effects on doxorubicin cardiotoxicity. This study examined the cellular effects of desacyl ghrelin on myocardial fibrosis and apoptosis in a doxorubicin cardiomyopathy experimental model. Adult C57BL/6 mice received an intraperitoneal injection of doxorubicin to induce cardiomyopathy, followed by 4-day treatment of saline (control) or desacyl ghrelin with or without [d-Lys3]-GHRP-6 (a growth hormone secretagogue receptor or GHSR1a antagonist). Ventricular structural and functional parameters were evaluated by transthoracic echocardiography. Molecular and cellular measurements were performed in ventricular muscle to examine myocardial fibrosis and apoptosis. Cardiac dysfunction was induced by doxorubicin, as indicated by significant decreases in ventricular fractional shortening and ejection fraction. This doxorubicin-induced cardiac dysfunction was prevented by the treatment of desacyl ghrelin no matter with or without the presence of [d-Lys3]-GHRP-6. Doxorubicin induced fibrosis (accumulated collagen deposition and increased CTGF), activated apoptosis (increased TUNEL index, apoptotic DNA fragmentation, and caspase-3 activity and decreased Bcl-2/Bax ratio), and suppressed phosphorylation status of prosurvival signals (ERK1/2 and Akt) in ventricular muscles. All these molecular and cellular alterations induced by doxorubicin were not found in the animals treated with desacyl ghrelin. Notably, the changes in the major markers of apoptosis, fibrosis, and Akt phosphorylation were found to be similar in the animals following the treatment of desacyl ghrelin with and without GHSR antagonist [d-Lys3]-GHRP-6. These findings demonstrate clearly that desacyl ghrelin protects the cardiomyocytes against the doxorubicin-induced cardiomyopathy by preventing the activation of cardiac fibrosis and apoptosis, and the effects are probably mediated through GHSR-independent mechanism.
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Affiliation(s)
- Xiao M Pei
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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Fu Z, Zou F, Deng H, Zhou H, Liu L. Estrogen protects SGC7901 cells from endoplasmic reticulum stress-induced apoptosis by the Akt pathway. Oncol Lett 2013; 7:560-564. [PMID: 24396487 PMCID: PMC3881920 DOI: 10.3892/ol.2013.1701] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 11/12/2013] [Indexed: 12/16/2022] Open
Abstract
Several previous studies have demonstrated that estrogen may protect cancer cells from endoplasmic reticulum stress-induced apoptosis. However, the molecular mechanisms involved are not fully understood. In the present study, human gastric adenocarcinoma SGC7901 cells were treated with tunicamycin (TM) to induce endoplasmic reticulum stress. This was demonstrated by increased glucose-regulated protein 78 expression and enhanced phosphorylation of protein kinase RNA-like endoplasmic reticulum kinase. Endoplasmic reticulum stress induced caspase-3-mediated apoptosis with the inhibition of Akt; the latter of which was measured by the activity-dependent phosphorylation at Ser473 of Akt. Simultaneous treatment of 10−9 M 17β-estradiol (E2) with TM may protect SGC7901 cells from endoplasmic reticulum stress-induced apoptosis by counteracting the inhibitory effect of TM on Akt, causing an increase in the phosphorylation of Ser473-Akt. It was concluded that low concentrations of E2 may counteract endoplasmic reticulum stress-induced inactivation of Akt to block caspase-3-mediated apoptosis.
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Affiliation(s)
- Zhengqi Fu
- Department of Pathology and Pathophysiology, School of Medicine, Wuhan, Hubei 430056, P.R. China ; Jiangda Pathology Institute, Jianghan University, Wuhan, Hubei 430056, P.R. China
| | - Feng Zou
- Department of Pathology and Pathophysiology, School of Medicine, Wuhan, Hubei 430056, P.R. China
| | - Hao Deng
- Department of Pathology and Pathophysiology, School of Medicine, Wuhan, Hubei 430056, P.R. China
| | - Hongyan Zhou
- Department of Pathology and Pathophysiology, School of Medicine, Wuhan, Hubei 430056, P.R. China
| | - Lijiang Liu
- Department of Pathology and Pathophysiology, School of Medicine, Wuhan, Hubei 430056, P.R. China ; Jiangda Pathology Institute, Jianghan University, Wuhan, Hubei 430056, P.R. China
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15
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Oiso S, Nobe M, Yamaguchi Y, Umemoto S, Nakamura K, Kariyazono H. Establishment of a Gastric Cell-Based Assay System for Exploring Inhibitors of Octanoylated Ghrelin Production. ACTA ACUST UNITED AC 2013; 18:1035-42. [DOI: 10.1177/1087057113489349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ghrelin, a gastric hormone, is a growth hormone-releasing peptide. Its serine-3 acylation with octanoic acid is essential for its orexigenic activity, and therefore, inhibition of the acylation of ghrelin may help in decreasing appetite and preventing obesity. This study aimed to establish a human gastric cell-based assay system to evaluate candidate inhibitors of octanoylated ghrelin production. In human gastric carcinoma AGS cells, obligatory factors for the posttranslational modification of ghrelin, such as certain prohormone convertases responsible for processing of proghrelin to the mature ghrelin and the enzyme-catalyzing acyl-modification of ghrelin, were well expressed, but ghrelin was expressed at low levels. Accordingly, we transfected a ghrelin-expressing vector into AGS cells and isolated a stable ghrelin-expressing cell line (AGS-GHRL8). AGS-GHRL8 cells secreted octanoylated ghrelin in accordance with the concentrations of octanoic acid in the culture medium. Given that ingested heptanoic acid is used for the acyl-modification of ghrelin, we evaluated whether heptanoic acid inhibits production of octanoylated ghrelin in AGS-GHRL8 cells. Butyric acid was used as a control. Indeed, heptanoic acid predictably decreased the secretion of octanoylated ghrelin, whereas butyric acid did not. The AGS-GHRL8 line established in this study will facilitate the screening of inhibitors of octanoylated ghrelin production.
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Affiliation(s)
- Shigeru Oiso
- Department of Pharmaceutical Health Care Sciences, Faculty of Pharmaceutical Sciences, Nagasaki International University, Huis Ten Bosch Sasebo, Nagasaki, Japan
| | - Miyuki Nobe
- Department of Pharmaceutical Health Care Sciences, Faculty of Pharmaceutical Sciences, Nagasaki International University, Huis Ten Bosch Sasebo, Nagasaki, Japan
| | - Yuhei Yamaguchi
- Department of Pharmaceutical Health Care Sciences, Faculty of Pharmaceutical Sciences, Nagasaki International University, Huis Ten Bosch Sasebo, Nagasaki, Japan
| | - Shigeru Umemoto
- Department of Pharmaceutical Health Care Sciences, Faculty of Pharmaceutical Sciences, Nagasaki International University, Huis Ten Bosch Sasebo, Nagasaki, Japan
| | - Kazuo Nakamura
- Department of Biopharmaceutics, Nihon Pharmaceutical University, Komuro, Ina-cho, Kitaadachi-Gun, Saitama, Japan
| | - Hiroko Kariyazono
- Department of Pharmaceutical Health Care Sciences, Faculty of Pharmaceutical Sciences, Nagasaki International University, Huis Ten Bosch Sasebo, Nagasaki, Japan
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Kirchner H, Heppner KM, Holland J, Kabra D, Tschöp MH, Pfluger PT. Ablation of ghrelin O-acyltransferase does not improve glucose intolerance or body adiposity in mice on a leptin-deficient ob/ob background. PLoS One 2013; 8:e61822. [PMID: 23630616 PMCID: PMC3632576 DOI: 10.1371/journal.pone.0061822] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 03/13/2013] [Indexed: 01/08/2023] Open
Abstract
Type 2 Diabetes is a global health burden and based on current estimates will become an even larger problem in the future. Developing new strategies to prevent and treat diabetes is a scientific challenge of high priority. The stomach hormone ghrelin has been associated with playing a role in the regulation of glucose homeostasis. However, its precise mechanism and impact on whole glucose metabolism remains to be elucidated. This study aims to clarify the role of the two ghrelin isoforms acyl- and desacyl ghrelin in regulating glucose homeostasis. Therefore ghrelin activating enzyme Ghrelin-O-acyltransferase (GOAT) was ablated in leptin-deficient ob/ob mice to study whether specific acyl ghrelin deficiency or desacyl ghrelin abundance modifies glucose tolerance on a massively obese background. As targeted deletion of acyl ghrelin does not improve glucose homeostasis in our GOAT-ob/ob mouse model we conclude that neither acyl ghrelin nor the increased ratio of desacyl/acyl ghrelin is crucial for controlling glucose homeostasis in the here presented model of massive obesity induced by leptin deficiency.
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Affiliation(s)
- Henriette Kirchner
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Kristy M. Heppner
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Jenna Holland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Dhiraj Kabra
- Institute for Diabetes and Obesity, Helmholtz Centre Munich, Neuherberg, Germany
| | - Matthias H. Tschöp
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
- Institute for Diabetes and Obesity, Helmholtz Centre Munich, Neuherberg, Germany
| | - Paul T. Pfluger
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
- Institute for Diabetes and Obesity, Helmholtz Centre Munich, Neuherberg, Germany
- * E-mail:
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17
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Chopin LK, Seim I, Walpole CM, Herington AC. The ghrelin axis--does it have an appetite for cancer progression? Endocr Rev 2012; 33:849-91. [PMID: 22826465 DOI: 10.1210/er.2011-1007] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHSR), is a peptide hormone with diverse physiological roles. Ghrelin regulates GH release, appetite and feeding, gut motility, and energy balance and also has roles in the cardiovascular, immune, and reproductive systems. Ghrelin and the GHSR are expressed in a wide range of normal and tumor tissues, and a fluorescein-labeled, truncated form of ghrelin is showing promise as a biomarker for prostate cancer. Plasma ghrelin levels are generally inversely related to body mass index and are unlikely to be useful as a biomarker for cancer, but may be useful as a marker for cancer cachexia. Some single nucleotide polymorphisms in the ghrelin and GHSR genes have shown associations with cancer risk; however, larger studies are required. Ghrelin regulates processes associated with cancer, including cell proliferation, apoptosis, cell migration, cell invasion, inflammation, and angiogenesis; however, the role of ghrelin in cancer is currently unclear. Ghrelin has predominantly antiinflammatory effects and may play a role in protecting against cancer-related inflammation. Ghrelin and its analogs show promise as treatments for cancer-related cachexia. Further studies using in vivo models are required to determine whether ghrelin has a role in cancer progression.
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Affiliation(s)
- Lisa K Chopin
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology and Australian Prostate Cancer Research Centre-Queensland, Brisbane, Queensland 4001, Australia.
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18
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Zhang R, Yang G, Wang Q, Guo F, Wang H. Acylated ghrelin protects hippocampal neurons in pilocarpine-induced seizures of immature rats by inhibiting cell apoptosis. Mol Biol Rep 2012; 40:51-8. [DOI: 10.1007/s11033-012-1993-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 10/01/2012] [Indexed: 01/26/2023]
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Rodríguez A, Gómez-Ambrosi J, Catalán V, Rotellar F, Valentí V, Silva C, Mugueta C, Pulido MR, Vázquez R, Salvador J, Malagón MM, Colina I, Frühbeck G. The ghrelin O-acyltransferase-ghrelin system reduces TNF-α-induced apoptosis and autophagy in human visceral adipocytes. Diabetologia 2012; 55:3038-50. [PMID: 22869322 DOI: 10.1007/s00125-012-2671-5] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/25/2012] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Proinflammatory and proapoptotic cytokines such as TNF-α are upregulated in human obesity. We evaluated the association between ghrelin isoforms (acylated and desacyl ghrelin) and TNF-α in obesity and obesity-associated type 2 diabetes, as well as the potential role of ghrelin in the control of apoptosis and autophagy in human adipocytes. METHODS Plasma concentrations of the ghrelin isoforms and TNF-α were measured in 194 participants. Ghrelin and ghrelin O-acyltransferase (GOAT) levels were analysed by western-blot, immunohistochemistry and real-time PCR in 53 biopsies of human omental adipose tissue. We also determined the effect of acylated and desacyl ghrelin (10 to 1,000 pmol/l) on TNF-α-induced apoptosis and autophagy-related molecules in omental adipocytes. RESULTS Circulating concentrations of acylated ghrelin and TNF-α were increased, whereas desacyl ghrelin levels were decreased in obesity-associated type 2 diabetes. Ghrelin and GOAT were produced in omental and subcutaneous adipose tissue. Visceral adipose tissue from obese patients with type 2 diabetes showed higher levels of GOAT, increased adipocyte apoptosis and increased expression of the autophagy-related genes ATG5, BECN1 and ATG7. In differentiating human omental adipocytes, incubation with acylated and desacyl ghrelin reduced TNF-α-induced activation of caspase-8 and caspase-3, and cell death. In addition, acylated ghrelin reduced the basal expression of the autophagy-related genes ATG5 and ATG7, while desacyl ghrelin inhibited the TNF-α-induced increase of ATG5, BECN1 and ATG7 expression. CONCLUSIONS/INTERPRETATION Apoptosis and autophagy are upregulated in human visceral adipose tissue of patients with type 2 diabetes. Acylated and desacyl ghrelin reduce TNF-α-induced apoptosis and autophagy in human visceral adipocytes.
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Affiliation(s)
- A Rodríguez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain
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20
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Majchrzak K, Pawłowski KM, Orzechowska EJ, Dolka I, Mucha J, Motyl T, Król M. A role of ghrelin in canine mammary carcinoma cells proliferation, apoptosis and migration. BMC Vet Res 2012; 8:170. [PMID: 22999388 PMCID: PMC3514346 DOI: 10.1186/1746-6148-8-170] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 09/20/2012] [Indexed: 11/13/2022] Open
Abstract
Background Ghrelin is a natural ligand of the growth hormone secretagogue receptor (GHS-R). They are often co-expressed in multiple human tumors and related cancer cell lines what can indicate that the ghrelin/GHS-R axis may have an important role in tumor growth and progression. However, a role of ghrelin in canine tumors remains unknown. Thus, the aim of our study was two-fold: (1) to assess expression of ghrelin and its receptor in canine mammary cancer and (2) to examine the effect of ghrelin on carcinoma cells proliferation, apoptosis, migration and invasion. The expression of ghrelin and its receptor in canine mammary cancer tissues and cell lines (isolated from primary tumors and their metastases) was examined using Real-time qPCR and immunohistochemistry. For apoptosis analysis the Annexin V and propidium iodide dual staining was applied whereas cell proliferation was evaluated by MTT assay and BrdU incorporation test. The influence of ghrelin on cancer cells migration and invasion was assessed using Boyden chamber assays and wound healing assay. Results The highest expression of ghrelin was observed in metastatic cancers whereas the lowest expression of ghrelin receptor was detected in tumors of the 3rd grade of malignancy. Higher expression of ghrelin and its receptor was detected in cancer cell lines isolated from metastases than in cell lines isolated from primary tumors. In vitro experiments demonstrated that exposure to low doses of ghrelin stimulates cellular proliferation, inhibits apoptosis and promotes motility and invasion of canine mammary cancer cells. Growth hormone secretagogue receptor inhibitor ([D-Lys3]-GHRP6) as well as RNA interference enhances early apoptosis. Conclusion The presence of ghrelin and GHS-R in all of the examined canine mammary tumors may indicate their biological role in cancer growth and development. Our experiments conducted in vitro confirmed that ghrelin promotes cancer development and metastasis.
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Affiliation(s)
- Kinga Majchrzak
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - WULS, Nowoursynowska 159, Warsaw, 02-776, Poland
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Food restriction, ghrelin, its antagonist and obestatin control expression of ghrelin and its receptor in chicken hypothalamus and ovary. Comp Biochem Physiol A Mol Integr Physiol 2012; 164:141-53. [PMID: 22877785 DOI: 10.1016/j.cbpa.2012.07.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/23/2012] [Accepted: 07/25/2012] [Indexed: 12/29/2022]
Abstract
The purpose of the present study was to identify the role of age, nutritional state and some metabolic hormones in control of avian hypothalamic and ovarian ghrelin/ghrelin receptor system. We examined the effect of food restriction, administration of ghrelin 1-18, ghrelin antagonistic analogue (D-Lys-3)-GHRP-6, obestatin and combinations of them on the expression of ghrelin and ghrelin receptor (GHS-R1a) in hypothalamus and ovary of old (23months of age) and young (7months of age) chickens. Expression of mRNAs for ghrelin and GHS-R1a in both hypothalamus and largest ovarian follicle was measured by RT-PCR. It was observed that food restriction could promote the expression of ghrelin and GHS-R1a in hypothalamus and ovary of the old chickens, but in the young chickens it reduced expression of ghrelin and did not affect expression of GHS-R1a in the ovary. Administration of ghrelin 1-18 did not affect hypothalamic or ovarian ghrelin mRNA, but significantly increased the expression of GHS-R1a in hypothalamus, but not in ovary. (D-Lys-3)-GHRP-6, significantly stimulated accumulation of ghrelin, but not GHS-R1a mRNA in hypothalamus or ghrelin or GHS-R1a in the ovary. Ghrelin 1-18 and (D-Lys-3)-GHRP-6, when given together, were able either to prevent or to induce effect of these hormones. Obestatin administration increased expression of ghrelin gene in the hypothalamus, but not expression of hypothalamic GHS-R1a, ovarian ghrelin and GHS-R1a. Furthermore, obestatin was able to modify effect of both ghrelin and fasting on hypothalamic and ovarian mRNA for ghrelin GHS-R1a. Our results (1) confirm the existence of ghrelin and its functional receptors GHS-R1a in the chicken hypothalamus and ovary (2) confirm the age-dependent control of ovarian ghrelin by feeding, (3) demonstrate, that nutritional status can influence the expression of both ghrelin and GHS-R1a in hypothalamus and in the ovary (3) demonstrates for the first time, that ghrelin can promote generation of its functional receptor in the hypothalamus, but not in the ovary, (4) show that ghrelin1-18 and (D-Lys-3)-GHRP-6 could not only be antagonists in the action on chicken hypothalamus and ovaries, but also independent regulators and even agonists, and (5) provide first evidence for action of obestatin on hypothalamic ghrelin and on the response of hypothalamic and ovarian ghrelin/GHS-R1a system to food restriction. These data indicate the involvement of both hypothalamic and ovarian ghrelin/GHS-R1 systems in mediating the effects of nutritional status, ghrelin and obestatin on reproductive processes.
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Aquino G, Pannone G, Santoro A, Liguori G, Franco R, Serpico R, Florio G, De Rosa A, Mattoni M, Cozza V, Botti G, Losito S, Longo F, Staibano S, Cuda G, Lo Muzio L, Sbordone C, Bufo P, Grimaldi A, Caraglia M, Di Domenico M. pEGFR-Tyr 845 expression as prognostic factors in oral squamous cell carcinoma: a tissue-microarray study with clinic-pathological correlations. Cancer Biol Ther 2012; 13:967-77. [PMID: 22825335 DOI: 10.4161/cbt.20991] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The EGFR (epidermal growth factor receptor) a member of the family of transmembrane protein kinase receptors known as the erbB family shows a significant correlation with the presence of metastases and poorly differentiated oral cancer. Aim of the present work is to define the key-role of EGFR in oral cancer prognosis. We have analyzed the EGFR expression on 149 cases of oral squamous cell cancers (OSCC) and we have found that it was poorly expressed in normal oral epithelium, but its expression was significantly increased in OSCCs. Moreover, we have recorded that both pEGFR-Tyr 845 and pEGFR-Tyr 1068 were mainly distributed in high histological grading and in advanced stages. Western blotting has confirmed the total absence of EGFR phosphorylation in normal oral epithelium and the higher level of protein phosphorylation in representative cases of OSCCs. The EGF-R amplification was found by fluorescence in situ hybridization (FISH) in 14% of OSCC; interestingly, EGF-R amplification was mainly observed in OSCC with higher histological grading (G2 and G3) and advanced stage (pT4) sub-groups. Kaplan-Meyer survival analysis suggested that patients with positive pEGFR-Tyr 845 tumors had a worse prognosis and were bad responders to chemotherapy. These results confirm the central role of EGF-R activation status as a prognostic biomarker in OSCC.
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Affiliation(s)
- Gabriella Aquino
- Section of Pathological Anatomy, Fourth Section of Maxillofacial Surgery, Istituto Nazionale per lo Studio e la Cura dei Tumori, Fondazione G.Pascale, Naples, Italy
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Rucinski M, Ziolkowska A, Szyszka M, Hochol A, Malendowicz LK. Evidence suggesting that ghrelin O-acyl transferase inhibitor acts at the hypothalamus to inhibit hypothalamo-pituitary-adrenocortical axis function in the rat. Peptides 2012; 35:149-59. [PMID: 22543218 DOI: 10.1016/j.peptides.2012.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 04/10/2012] [Accepted: 04/10/2012] [Indexed: 10/28/2022]
Abstract
Production of n-octanoyl-modified ghrelin (GHREL), an active form of the peptide requires prohormone processing protease and GHREL O-acyltransferase (GOAT), as well as n-octanoic acid. Recently a selective GOAT antagonist (GO-CoA-Tat) was invented and this tool was used to study the possible role of endogenous GHREL in regulating HPA axis function in the rat. Administration of GOAT inhibitor (GOATi) resulted in a notable decrease in plasma ACTH, aldosterone and corticosterone concentrations at min 60 of experiment. Octanoic acid (OA) administration had no effect on levels of studied hormones. Plasma levels of unacylated and acylated GHREL remained unchanged for 60min after either GOATi or OA administration. Under experimental conditions applied, no significant changes were observed in the levels of GOAT mRNA in hypothalamus, pituitary, adrenal and stomach fundus. After GOATi injection hypothalamic CRH mRNA levels were elevated at 30 min and pituitary POMC mRNA levels at 60 min. Both GOATi and OA lowered basal, but not K(+)-stimulated CRH release by hypothalamic explants and had no effect on basal or CRH-stimulated ACTH release by pituitary slices. Neither GOATi nor OA affected corticosterone secretion by freshly isolated or cultured rat adrenocortical cells. Thus, results of our study suggest that in the rat endogenous GHREL exerts tonic stimulating effect on hypothalamic CRH release. This effect could be demonstrated by administering rats with selected inhibitor of ghrelin O-acyltransferase, the enzyme responsible for GHREL acylation, a process which is absolutely required for both GHSR-1a binding and its central endocrine activities.
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Affiliation(s)
- Marcin Rucinski
- Department of Histology and Embryology, Medical University, Poznan, Poland
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25
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Fung JNT, Seim I, Wang D, Obermair A, Chopin LK, Chen C. Expression and in vitro functions of the ghrelin axis in endometrial cancer. Discov Oncol 2011; 1:245-55. [PMID: 21761369 DOI: 10.1007/s12672-010-0047-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ghrelin is a peptide hormone produced in the stomach and a range of other tissues, where it has endocrine, paracrine and autocrine roles in both normal and disease states. Ghrelin has been shown to be an important growth factor for a number of tumours, including prostate and breast cancers. In this study, we examined the expression of the ghrelin axis (ghrelin and its receptor, the growth hormone secretagogue receptor, GHSR) in endometrial cancer. Ghrelin is expressed in a range of endometrial cancer tissues, while its cognate receptor, GHSR1a, is expressed in a small subset of normal and cancer tissues. Low to moderately invasive endometrial cancer cell lines were examined by RT-PCR and immunoblotting, demonstrating that ghrelin axis mRNA and protein expression correlate with differentiation status of Ishikawa, HEC1B and KLE endometrial cancer cell lines. Moreover, treatment with ghrelin potently stimulated cell proliferation and inhibited cell death. Taken together, these data indicate that ghrelin promotes the progression of endometrial cancer cells in vitro, and may contribute to endometrial cancer pathogenesis and represent a novel treatment target.
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Affiliation(s)
- Jenny N T Fung
- Department of Physiology and Pharmacology, School of Biomedical Sciences, The University of Queensland, Brisbane QLD 4072, Australia
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Satou M, Nakamura Y, Ando H, Sugimoto H. Understanding the functional significance of ghrelin processing and degradation. Peptides 2011; 32:2183-90. [PMID: 21763742 DOI: 10.1016/j.peptides.2011.06.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 06/08/2011] [Accepted: 06/30/2011] [Indexed: 10/18/2022]
Abstract
Post-translational modification, cleavage and processing of circulating hormones are common themes in the control of hormone activities. Full-length ghrelin is a 28 amino acid protein that exists in several modified and processed forms, including addition of an acyl moiety at the third serine of the N-terminus. When modified with octanoic acid, the first five N-terminal residues of ghrelin can modulate a signaling pathway via the ghrelin receptor GHSR1a. Although modification via a lipid moiety is essential for binding and activation of GHSR1a by ghrelin, many reports suggest that a desacyl form of ghrelin exists and has synergistic, opposing and distinct properties as compared to the acyl form. Therefore, it is important to clarify the physiological relevance of ghrelin derivatives. Based on lines of evidence from various studies, we propose that a larger proportion of secreted ghrelin is present in the deacylated form and furthermore, that circulating acyl and desacyl forms of ghrelin may be hydrolyzed to form short peptide fragments. Here, we summarize the results of studies aimed at understanding ghrelin processing and its implications for physiological function, as well as our recent findings regarding enzymes in the blood capable of generating processed forms of ghrelin.
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Affiliation(s)
- Motoyasu Satou
- Departments of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
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Sirotkin AV, Meszarošová M, Grossmann R, Benčo A, Valenzuela F. Effect of inhibitor and activator of ghrelin receptor (GHS-R1a) on porcine ovarian granulosa cell functions. Gen Comp Endocrinol 2011; 173:105-10. [PMID: 21600209 DOI: 10.1016/j.ygcen.2011.05.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 05/01/2011] [Accepted: 05/02/2011] [Indexed: 02/07/2023]
Abstract
It was previously shown, that ghrelin and its agonistic analogue, ghrelin 1-18, can be a stimulator of ovarian cell functions (promoter of proliferation, inhibitor of apoptosis and stimulator of hormones release). The aim of our studies was to compare the action of two ghrelin analogues - ghrelin 1-18, activator of ghrelin receptors (GHS-R1a), and (D-Lys3)-GHRP-6, its inhibitor, on porcine ovarian granulosa cell functions. Effects of (D-Lys3)-GHRP-6 added at doses of 0, 1, 10 or 100 ng/ml on the expression of markers of proliferation (PCNA, cyclin B1, MAPK/ERK1,2), apoptosis (bax, p53, caspase 3) and release of steroid hormones (progesterone, testosterone, estradiol) were examined. In addition, some effect of ghrelin 1-8 on some of these parameters (expression of MAPK/ERK1,2, bax, p53) were verified. It was shown, that (D-Lys3)-GHRP-6 promotes all markers of granulosa cell proliferation, inhibits all markers of apoptosis and stimulates the release of all three steroid hormones. Similar effects of (D-Lys3)-GHRP-6 (inhibitor of GHS-R1a) and ghrelin 1-18 (its stimulator) suggest that the examined effects of these substances on porcine ovaries are not mediated by GHS-R1a. Both chemical analogues could be potentially useful for stimulation of reproductive processes, at least in in vitro conditions.
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Affiliation(s)
- Alexander V Sirotkin
- Institute of Genetics and Reproduction, Animal Production Research Centre Nitra, 951 41 Lužianky near Nitra, Slovakia.
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Chopin L, Walpole C, Seim I, Cunningham P, Murray R, Whiteside E, Josh P, Herington A. Ghrelin and cancer. Mol Cell Endocrinol 2011; 340:65-9. [PMID: 21616120 DOI: 10.1016/j.mce.2011.04.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 04/18/2011] [Accepted: 04/21/2011] [Indexed: 01/30/2023]
Abstract
Ghrelin is a peptide hormone that was originally isolated from the stomach as the endogenous ligand for the growth hormone secretagogue receptor (GHSR). Ghrelin has many functions, including the regulation of appetite and gut motility, growth hormone release from the anterior pituitary and roles in the cardiovascular and immune systems. Ghrelin and its receptor are expressed in a number of cancers and cancer cell lines and may play a role in processes associated with cancer progression, including cell proliferation, apoptosis, and cell invasion and migration.
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Affiliation(s)
- Lisa Chopin
- Queensland University of Technology, Brisbane, Australia.
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29
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Angelidis G, Valotassiou V, Georgoulias P. Current and potential roles of ghrelin in clinical practice. J Endocrinol Invest 2010; 33:823-38. [PMID: 21293171 DOI: 10.1007/bf03350350] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ghrelin is a novel GH-releasing peptide, which has been identified as an endogenous ligand for GH-secretagogue receptor. Ghrelin is mainly secreted by the stomach and plays a critical role in a variety of physiological processes including endocrine, metabolic, cardiovascular, immunological, and other actions. Ghrelin stimulates food intake via hypothalamic neurons and causes a positive energy balance and body weight gain by decreasing fat utilization and promoting adiposity. Given the multiple effects of ghrelin, its potential clinical applications have been evaluated in various conditions. Preliminary trials have shown that it may prove valuable in the management of disease-induced cachexia. Ghrelin may improve the wasting syndrome through GH-dependent or GH-independent effects. Moreover, ghrelin may play a role in the management of disorders of gut motility and obesity. Finally, other potential clinical applications of ghrelin include the treatment of patients with diabetes mellitus, infections, rheumatological diseases or GH deficiency and the diagnosis of this hormonal disorder.
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Affiliation(s)
- G Angelidis
- Department of Nuclear Medicine, University Hospital of Larissa, Mezourlo, Larissa, Hellas
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Satou M, Nishi Y, Yoh J, Hattori Y, Sugimoto H. Identification and characterization of acyl-protein thioesterase 1/lysophospholipase I as a ghrelin deacylation/lysophospholipid hydrolyzing enzyme in fetal bovine serum and conditioned medium. Endocrinology 2010; 151:4765-75. [PMID: 20685872 DOI: 10.1210/en.2010-0412] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ghrelin contains an octanoic acid at the third residue serine, and the presence of octanoic acid on ghrelin is critical to its physiological functions. The precise mechanism for the deacylation of ghrelin in circulation remains to be clarified, although the level of deacylated ghrelin (des-acyl ghrelin) is higher than that of acylated ghrelin in serum. In this study, rapid identification of ghrelin deacylation activity was achieved by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and a ghrelin deacylation enzyme was purified 1515-fold from fetal bovine serum. Chromatographic separation showed a 24-kDa band on SDS-PAGE corresponding to ghrelin deacylation activity, and the protein band was identified as acyl-protein thioesterase 1 (APT1)/lysophospholipase I. A ghrelin deacylation enzyme in medium from HepG2 cells was also purified and identified as APT1. Although it lacks a secretion signal sequence, APT1 may be released by cells expressing APT1, mainly from liver in vivo. APT1 was originally purified as a cytosolic lysophospholipid hydrolyzing enzyme (lysophospholipase I), and recombinant APT1 exhibited deacylation activity as well as lysophospholipase activity in vitro. APT1 is released at high levels from RAW264.7 macrophage-like cells into the culture medium after stimulation with lipopolysaccharide (LPS), and LPS suppresses APT1 mRNA and protein expressions in these cells. More potent ghrelin deacylase activities were detected in sera from LPS-treated rats than in control sera. These results suggested that the serum activity of APT1 may play an important role in determination of the concentration of des-acyl ghrelin in circulation, especially under septic inflammation.
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Affiliation(s)
- Motoyasu Satou
- Department of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
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31
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Nikolopoulos D, Theocharis S, Kouraklis G. Ghrelin: a potential therapeutic target for cancer. ACTA ACUST UNITED AC 2010; 163:7-17. [PMID: 20382189 DOI: 10.1016/j.regpep.2010.03.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 03/24/2010] [Accepted: 03/25/2010] [Indexed: 01/14/2023]
Abstract
Ghrelin is a recently identified 28-amino-acid peptide, capable of stimulating pituitary growth hormone release in humans and other mammals. It is mainly secreted from the gastric mucosa, but it is also widely expressed in a variety of tissues, in both normal and malignant conditions. Ghrelin has a multiplicity of physiological functions in gastrointestinal, cardiovascular, pulmonary and immune system, and also exerts a variety of roles, from increasing food intake (orexigenic effect) to affecting cell proliferation. The actions of ghrelin are mediated by the ghrelin receptor, also known as the growth hormone secretagogue receptor (GHS-R). The purpose of this review is to provide an overview of the expression and putative role of ghrelin and its receptor in cancer. Ghrelin and its receptor are detected in tumor tissues, and evidence is emerging that ghrelin plays an autocrine/paracrine role in cancer and could serve as a diagnostic or prognostic tool or as therapeutic target.
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Affiliation(s)
- Dimitrios Nikolopoulos
- 2nd Department of Propedeutic Surgery, University of Athens, Medical School, Laiko General Hospital, Athens, Greece.
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Veldhuis JD, Bowers CY. Integrating GHS into the Ghrelin System. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010:879503. [PMID: 20798846 PMCID: PMC2925380 DOI: 10.1155/2010/879503] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/30/2009] [Indexed: 12/21/2022]
Abstract
Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.
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Affiliation(s)
- Johannes D. Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN 55905, USA
| | - Cyril Y. Bowers
- Division of Endocrinology, Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Rucinski M, Ziolkowska A, Tyczewska M, Malendowicz LK. Expression of prepro-ghrelin and related receptor genes in the rat adrenal gland and evidences that ghrelin exerts a potent stimulating effect on corticosterone secretion by cultured rat adrenocortical cells. Peptides 2009; 30:1448-55. [PMID: 19416745 DOI: 10.1016/j.peptides.2009.04.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 04/24/2009] [Accepted: 04/25/2009] [Indexed: 11/30/2022]
Abstract
The orexigenic peptide ghrelin (GHREL) and obestatin (OBS) originate from the same peptide precursor, preproghrelin (ppGHREL). Apart from orexigenic effect, GHREL also regulates neuroendocrine function. We investigated GHREL and OBS effects on corticosterone secretion by freshly isolated and cultured rat adrenocortical cells. Classic RT-PCR revealed the presence of ppGHREL, GHS-R1a, GPR39v1 and GPR39v2 and GOAT4 (ghrelin O-acyl transferase) mRNAs in rat adrenals and cultured for 4 days rat adrenocortical cells. Expression of ppGHREL, GHS-R1a, and GOAT genes was notably higher in the cortex than in medulla. High expression level of GOAT gene was found in the zona glomerulosa, while expression level of both GPR39v1 and GPR39v2 genes was similar in adrenal cortical zones and in medulla. In freshly isolated cells neither GHREL nor OBS had an effect on corticosteroid output. Prolonged exposure of cultured cells to GHREL resulted in a potent, comparable to ACTH, stimulating effect of GHREL on corticosterone secretion. Prolonged exposure to OBS was ineffective. Neither GHREL nor OBS had any effect on proliferation of studied cells, while ACTH notably lowered it. GHREL down regulated GHS-R1a gene expression while both ACTH and GHREL stimulated expression level of GPR39v1 gene. Expression of CYP11A1 gene was notably stimulated and that of StAR gene remained unaffected by ACTH or GHREL. Thus, our study is the first to demonstrate direct stimulating effect of GHREL on corticosterone output by cultured rat adrenocortical cells. This stimulating action differs from that evoked by ACTH and is not dependent on the presence of functional ACTH receptor.
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Affiliation(s)
- Marcin Rucinski
- Department of Histology and Embryology, Medical University, 6 Swiecicki Street, 60-781 Poznan, Poland
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Abstract
Ghrelin is a peptide hormone that possesses unique orexigenic properties. By acting on the growth-hormone secretagogue receptor 1a, ghrelin induces a short-term increase in food consumption, which ultimately induces a positive energy balance and increases fat deposition. Reduced ghrelin levels have been observed in obese patients and after bariatric surgery. In particular, bariatric procedures that involve gastric resection or bypass lead to reduced ghrelin levels. Administration of physiological doses of exogenous ghrelin to humans does not significantly alter gastric motility; however, administration of high doses stimulates gastric motility, with increased gastric tone and emptying, and increased activity of migrating motor complexes in the small bowel. The potential of ghrelin agonists to be used as prokinetics is being tested in patients with gastroparesis and postoperative ileus. Ghrelin acts directly on pancreatic islet cells to reduce insulin production. Findings from studies in animals have revealed that small-molecule ghrelin antagonists favorably influence glucose tolerance, appetite suppression and weight loss. Other studies have demonstrated that ghrelin antagonists retard gastric emptying only at very high doses, which suggests that these agents will probably not induce upper gastrointestinal symptoms. The potential of this new class of therapeutic agents to influence appetite and glycemic control strongly indicates that they should be tested in clinical trials.
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Nikolopoulos D, Theocharis S, Kouraklis G. Ghrelin's role on gastrointestinal tract cancer. Surg Oncol 2009; 19:e2-e10. [PMID: 19328680 DOI: 10.1016/j.suronc.2009.02.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 01/10/2009] [Accepted: 02/14/2009] [Indexed: 12/15/2022]
Abstract
Ghrelin is a recently identified 28-amino-acid peptide, with pituitary growth hormone releasing activities in humans and other mammals. In mammals, ghrelin plays a variety of roles, including influence on food intake, gastric motility, and acid secretion of the gastrointestinal tract. It is mainly secreted from the stomach mucosa, but it is also expressed widely in other tissues - in normal and malignant conditions - and, therefore, ghrelin may exert such variable endocrine and paracrine effects, as autocrine and/or paracrine function in cancer. Ghrelin's actions are mediated via its receptor, known as growth hormone secretagogue receptor (GHS-R), type 1a and 1b. Several endocrine and non-endocrine cancers, such as gastro-entero-pancreatic carcinoids, colorectal neoplasms, pituitary adenomas, pulmonary and thyroid tumours, as well as lung, breast, and pancreatic carcinomas express ghrelin at both mRNA and protein levels. In the current review, we summarise the available so far data with regard to: (a) the structure of the ghrelin molecule and its receptor; (b) its tissue contribution in physiologic and neoplasmatic conditions; and (c) ghrelin's possible role in carcinogenesis; specifically, in the area of gastrointestinal tract cancer. The aim of the present study is to determine whether or not ghrelin promotes the proliferation rate of the gastrointestinal tract (GIT) tumours.
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Affiliation(s)
- Dimitrios Nikolopoulos
- 2nd Department of Propedeutic Surgery, University of Athens, Medical School, Laiko General Hospital, Athens, Greece.
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Xu J, Wang S, Lin Y, Cao L, Wang R, Chi Z. Ghrelin protects against cell death of hippocampal neurons in pilocarpine-induced seizures in rats. Neurosci Lett 2009; 453:58-61. [DOI: 10.1016/j.neulet.2009.01.067] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 01/25/2009] [Accepted: 01/26/2009] [Indexed: 10/21/2022]
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Rak A, Szczepankiewicz D, Gregoraszczuk EŁ. Expression of ghrelin receptor, GHSR-1a, and its functional role in the porcine ovarian follicles. Growth Horm IGF Res 2009; 19:68-76. [PMID: 18809347 DOI: 10.1016/j.ghir.2008.08.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 08/05/2008] [Accepted: 08/12/2008] [Indexed: 11/21/2022]
Abstract
Recently, we reported stimulatory effect of ghrelin alone and in combination with growth hormone (GH) on estradiol secretion, aromatase activity in parallel with inhibitory effect on cell apoptosis. The aim of this study was to analyze the expression of the functional ghrelin receptor (GHS-R type 1a) and the effect of GH on GHSR-1a expression in cultured whole porcine follicles. Using RT-PCR and Western Blots, we demonstrated the presence of GHSR-1a in prepubertal pig ovary and found no influence of GH on either GHSR-1a protein levels or mRNA expression. Additionally, to show if, noted previously by us action of ghrelin on ovarian follicular function is dependent of its binding to GHSR-1a, we used an antagonist of the ghrelin receptor, (D-Lys-3)-GHRP-6. In cultures treated together ghrelin and (D-Lys-3)-GHRP-6, estradiol secretion, aromatase activity and cell proliferation returned to control levels. Inhibitory action on caspase-3 activity was not reversed by a selective antagonist of GHSR-1a. In conclusion, results of the present data clearly showed: (1) the presence of GHSR-1a in prepubertal pig ovary and found no influence of GH on GHSR-1a protein levels and mRNA expression, and (2) ghrelin effect on estradiol secretion, aromatase activity and cell proliferation dependent of its binding to GHSR-1a, while the effect on cellular apoptosis was independent of its binding to GHSR-1a.
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Affiliation(s)
- Agnieszka Rak
- Department of Physiology and Toxicology of Reproduction, Chair of Animal Physiology, Institute of Zoology, Jagiellonian University, Kraków, Poland
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Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize recent studies that investigated the role of ghrelin and ghrelin analogs in wasting conditions. RECENT FINDINGS Numerous studies have demonstrated potential beneficial effects exerted by ghrelin in a number of diseases associated with wasting. Besides ghrelin's orexigenic effect, anabolic as well as anti-inflammatory activity mediated by ghrelin have been investigated in wasting conditions such as cancer, diabetes mellitus, malabsorptive diseases, chronic obstructive pulmonary disease, anorexia nervosa, renal failure, liver failure, and chronic heart failure. Encouraging results have been obtained from experimental studies and a few clinical trials using subcutaneous administration of ghrelin and ghrelin agonists in cachexia. In-vitro studies have shown ghrelin and des-acyl ghrelin biological activities on proliferation of tumor cells and abnormal tissues. SUMMARY The recent studies support the possible positive effects of ghrelin in therapeutic approaches and adjunct treatment of a number of diseases associated with wasting. Utilization of agonists of the ghrelin receptor growth hormone secretagogue-1a is a promising approach for clinical use. Randomized and placebo-controlled studies, including large number of patients are further required.
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Affiliation(s)
- Mayra M Kamiji
- Department of Gastroenterology, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil
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39
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Bibliography. Current world literature. Adrenal cortex. Curr Opin Endocrinol Diabetes Obes 2008; 15:284-299. [PMID: 18438178 DOI: 10.1097/med.0b013e3283040e80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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