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Lee S, Cai WT, Yoon HS, Kim JH. Visualization of the existence of growth hormone secretagogue receptor in the rat nucleus accumbens. Mol Brain 2024; 17:37. [PMID: 38872222 PMCID: PMC11177452 DOI: 10.1186/s13041-024-01109-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 06/04/2024] [Indexed: 06/15/2024] Open
Abstract
The potential role of the ghrelin receptor, also known as the growth hormone secretagogue receptor (GHSR), within the nucleus accumbens (NAcc) in regulating drug addiction and feeding has been documented; however, the pattern of its expression in this site remains elusive. In this study, we characterized the expression patterns of GHSR1a and 1b, two subtypes of GHSRs, within the NAcc of the rat brain by immunohistochemistry. We visually detected GHSR signals, for the first time, at the protein level in the NAcc in which they were mostly expressed in neurons including both medium spiny neurons (MSNs) and non-MSNs. Furthermore, GHSR1a was found expressed as localized near the cellular membrane or some in the cytoplasm, whereas GHSR1b expressed solely throughout the large cytoplasmic area. The existence and subcellular expression pattern of GHSRs in the NAcc identified in this study will contribute to improving our understanding about the role of GHSR-mediated neurosignaling in feeding and drug addiction.
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Affiliation(s)
- Seohyeon Lee
- Department of Medical Sciences, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Wen Ting Cai
- Department of Physiology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Hyung Shin Yoon
- Department of Physiology, Yonsei University College of Medicine, Seoul, 03722, South Korea.
| | - Jeong-Hoon Kim
- Department of Medical Sciences, Yonsei University College of Medicine, Seoul, 03722, South Korea.
- Department of Physiology, Yonsei University College of Medicine, Seoul, 03722, South Korea.
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2
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Vijayashankar U, Ramashetty R, Rajeshekara M, Vishwanath N, Yadav AK, Prashant A, Lokeshwaraiah R. Leptin and ghrelin dynamics: unraveling their influence on food intake, energy balance, and the pathophysiology of type 2 diabetes mellitus. J Diabetes Metab Disord 2024; 23:427-440. [PMID: 38932792 PMCID: PMC11196531 DOI: 10.1007/s40200-024-01418-2] [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: 12/29/2023] [Accepted: 03/12/2024] [Indexed: 06/28/2024]
Abstract
Purpose Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by insulin resistance and impaired glucose homeostasis. In recent years, there has been growing interest in the role of hunger and satiety hormones such as ghrelin and leptin in the development and progression of T2DM. In this context, the present literature review aims to provide a comprehensive overview of the current understanding of how ghrelin and leptin influences food intake and maintain energy balance and its implications in the pathophysiology of T2DM. Methods A thorough literature search was performed using PubMed and Google Scholar to choose the studies that associated leptin and ghrelin with T2DM. Original articles and reviews were included, letters to editors and case reports were excluded. Results This narrative review article provides a comprehensive summary on mechanism of action of leptin and ghrelin, its association with obesity and T2DM, how they regulate energy and glucose homeostasis and potential therapeutic implications of leptin and ghrelin in managing T2DM. Conclusion Ghrelin, known for its appetite-stimulating effects, and leptin, a hormone involved in the regulation of energy balance, have been implicated in insulin resistance and glucose metabolism. Understanding the complexities of ghrelin and leptin interactions in the context of T2DM may offer insights into novel therapeutic strategies for this prevalent metabolic disorder. Further research is warranted to elucidate the molecular mechanisms underlying these hormone actions and to explore their clinical implications for T2DM prevention and management.
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Affiliation(s)
- Uma Vijayashankar
- Department of Physiology, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru, 570015 India
| | - Rajalakshmi Ramashetty
- Department of Physiology, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru, 570015 India
| | - Mahesh Rajeshekara
- Department of Surgical Gastroenterology, Bangalore Medical College and Research Institute, Bangalore, 560002 India
| | - Nagashree Vishwanath
- Department of Physiology, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru, 570015 India
| | - Anshu Kumar Yadav
- Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru-15, Mysuru, 570015 India
| | - Akila Prashant
- Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru-15, Mysuru, 570015 India
| | - Rajeshwari Lokeshwaraiah
- Department of Physiology, JSS Medical College, JSS Academy of Higher Education & Research, Mysuru, 570015 India
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Han HW, Pradhan G, Villarreal D, Kim DM, Jain A, Gaharwar A, Tian Y, Guo S, Sun Y. GHSR Deletion in β-Cells of Male Mice: Ineffective in Obesity, but Effective in Protecting against Streptozotocin-Induced β-Cell Injury in Aging. Nutrients 2024; 16:1464. [PMID: 38794702 PMCID: PMC11123813 DOI: 10.3390/nu16101464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Insulin secretion from pancreatic β cells is a key pillar of glucose homeostasis, which is impaired under obesity and aging. Growth hormone secretagogue receptor (GHSR) is the receptor of nutrient-sensing hormone ghrelin. Previously, we showed that β-cell GHSR regulated glucose-stimulated insulin secretion (GSIS) in young mice. In the current study, we further investigated the effects of GHSR on insulin secretion in male mice under diet-induced obesity (DIO) and streptozotocin (STZ)-induced β-cell injury in aging. β-cell-specific-Ghsr-deficient (Ghsr-βKO) mice exhibited no glycemic phenotype under DIO but showed significantly improved ex vivo GSIS in aging. We also detected reduced insulin sensitivity and impaired insulin secretion during aging both in vivo and ex vivo. Accordingly, there were age-related alterations in expression of glucose transporter, insulin signaling pathway, and inflammatory genes. To further determine whether GHSR deficiency affected β-cell susceptibility to acute injury, young, middle-aged, and old Ghsr-βKO mice were subjected to STZ. We found that middle-aged and old Ghsr-βKO mice were protected from STZ-induced hyperglycemia and impaired insulin secretion, correlated with increased expression of insulin signaling regulators but decreased pro-inflammatory cytokines in pancreatic islets. Collectively, our findings indicate that β-cell GHSR has a major impact on insulin secretion in aging but not obesity, and GHSR deficiency protects against STZ-induced β-cell injury in aging.
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Affiliation(s)
- Hye Won Han
- Department of Nutrition, Texas A&M University, College Station, TX 77843, USA; (H.W.H.)
| | - Geetali Pradhan
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniel Villarreal
- Department of Nutrition, Texas A&M University, College Station, TX 77843, USA; (H.W.H.)
| | - Da Mi Kim
- Department of Nutrition, Texas A&M University, College Station, TX 77843, USA; (H.W.H.)
| | - Abhishek Jain
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Akhilesh Gaharwar
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Yanan Tian
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Shaodong Guo
- Department of Nutrition, Texas A&M University, College Station, TX 77843, USA; (H.W.H.)
| | - Yuxiang Sun
- Department of Nutrition, Texas A&M University, College Station, TX 77843, USA; (H.W.H.)
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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4
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Esteban JJ, Mason JR, Kaminski J, Ramachandran R, Luyt LG. A survey of stapling methods to increase affinity, activity, and stability of ghrelin analogues. RSC Med Chem 2024; 15:254-266. [PMID: 38283230 PMCID: PMC10809362 DOI: 10.1039/d3md00441d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/29/2023] [Indexed: 01/30/2024] Open
Abstract
The growth hormone secretagogue receptor (GHSR) is a G protein-coupled receptor which regulates various important physiological and pathophysiological processes in the body such as energy homeostasis, growth hormone secretion and regulation of appetite. As a result, it has been postulated as a potential therapeutic target for the treatment of cancer cachexia and other metabolic disorders, as well as a potential imaging agent target for cancers and cardiovascular diseases. Ghrelin is the primary high affinity endogenous ligand for GHSR and has limited secondary structure in solution, which makes it proteolytically unstable. This inherent instability in ghrelin can be overcome by incorporating helix-inducing staples that stabilize its structure and improve affinity and activity. We present an analysis of different stapling methods at positions 12 and 16 of ghrelin(1-20) analogues with the goal of increasing proteolytic stability and to retain or improve affinity and activity towards the GHSR. Ghrelin(1-20) analogues were modified with a wide range of chemical staples, including a lactam staple, triazole staple, hydrocarbon staple, Glaser staple, and xylene-thioether staple. Once synthesized, the receptor affinity and α-helicity were measured using competitive binding assays and circular dichroism spectroscopy, respectively. Generally, an increase in alpha-helicity using a flexible staple linker led to improved affinity towards GHSR. Ghrelin(1-20) analogues with a lactam, triazole, and hydrocarbon staple resulted in helical analogues with stronger affinity towards GHSR than unstapled ghrelin(1-20), a compound that lacks helical character. Compounds were also investigated for their agonist activity through β-arrestin 1 & 2 recruitment BRET assays and for their metabolic stability through serum stability analysis.
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Affiliation(s)
- Juan J Esteban
- Department of Chemistry, University of Western Ontario 1151 Richmond Street London Ontario N6A 3K7 Canada
| | - Julia R Mason
- Department of Chemistry, University of Western Ontario 1151 Richmond Street London Ontario N6A 3K7 Canada
| | - Jakob Kaminski
- Department of Chemistry, University of Western Ontario 1151 Richmond Street London Ontario N6A 3K7 Canada
| | - Rithwik Ramachandran
- Department of Physiology and Pharmacology, University of Western Ontario 1151 Richmond Street London Ontario N6A 5C1 Canada
| | - Leonard G Luyt
- Department of Chemistry, University of Western Ontario 1151 Richmond Street London Ontario N6A 3K7 Canada
- Departments of Medical Imaging and Oncology, University of Western Ontario 1151 Richmond Street London Ontario N6A 3K7 Canada
- London Regional Cancer Program, Lawson Health Research Institute 800 Commissioners Road East London Ontario N6A 4L6 Canada
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5
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Beheshti S, Ershadi S, Zamani F, Azimzadeh M, Wesal MW. Differential impact of a ghrelin receptor antagonist or inverse agonist in the electrical kindling model of epilepsy. Epilepsy Res 2023; 197:107234. [PMID: 37793283 DOI: 10.1016/j.eplepsyres.2023.107234] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/23/2023] [Accepted: 09/28/2023] [Indexed: 10/06/2023]
Abstract
Ghrelin is a peptide, which has been shown to affect seizures. However, there is not a consensus about its real impact on the control of seizure severity. We assessed the influence of intra-amygdala injections of a ghrelin receptor (GHSR) antagonist, as well as a GHSR inverse agonist on the electrical kindling-induced seizures. Two unipolar electrodes and a tripolar electrode twisted with a guide cannula were implanted in the skull surface or the basolateral amygdala of adult male rats, respectively. A rapid electrical kindling protocol was applied for kindling epileptogenesis. The stimulations were applied until rats showed three consecutive stage five seizures. Each rat was considered as its control. D-Lys-3-GHRP-6 (1, 12.5, and 25 μg/rat) or [D-Arg, D-phe, D-Trp, heu] substance P (D-SP) (50, 500 and 5000 ng/rat) as the GHSR antagonist or inverse agonist were injected into the basolateral amygdala. Seizure parameters including after-discharge duration (ADD), stage five duration (S5D), and seizure stage (SS) were documented thirty minutes following administration of the drugs or saline. Antagonism of the GHSR in the amygdala, significantly increased seizure induction in the kindled rats, in a dose-dependent manner, and induced spontaneous seizures leading to status epilepticus. Conversely, D-SP had a dose-dependent anticonvulsant activity, indicated by decreased ADD and S5D. The results show that GHSR inverse agonism suppressed seizure severity in the rat amygdala kindling model, whereas GHSR antagonism made seizures more severe. Therefore, when considering the ghrelin system to modulate seizures, it is crucial to note the differential impact of various GHSR ligands.
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Affiliation(s)
- Siamak Beheshti
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
| | - Shiva Ershadi
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Fatemeh Zamani
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Mansour Azimzadeh
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran; Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysis, 43400 UPM Serdang, Selangor, Malaysia
| | - Mohammad Wasil Wesal
- Department of Biology, Faculty of Education, University of Ghazni, Gazni, Afghanistan
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Jin R, Sun S, Hu Y, Zhang H, Sun X. Neuropeptides Modulate Feeding via the Dopamine Reward Pathway. Neurochem Res 2023:10.1007/s11064-023-03954-4. [PMID: 37233918 DOI: 10.1007/s11064-023-03954-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/13/2023] [Accepted: 05/16/2023] [Indexed: 05/27/2023]
Abstract
Dopamine (DA) is a catecholamine neurotransmitter widely distributed in the central nervous system. It participates in various physiological functions, such as feeding, anxiety, fear, sleeping and arousal. The regulation of feeding is exceptionally complex, involving energy homeostasis and reward motivation. The reward system comprises the ventral tegmental area (VTA), nucleus accumbens (NAc), hypothalamus, and limbic system. This paper illustrates the detailed mechanisms of eight typical orexigenic and anorexic neuropeptides that regulate food intake through the reward system. According to recent literature, neuropeptides released from the hypothalamus and other brain regions regulate reward feeding predominantly through dopaminergic neurons projecting from the VTA to the NAc. In addition, their effect on the dopaminergic system is mediated by the prefrontal cortex, paraventricular thalamus, laterodorsal tegmental area, amygdala, and complex neural circuits. Research on neuropeptides involved in reward feeding can help identify more targets to treat diseases with metabolic disorders, such as obesity.
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Affiliation(s)
- Ruijie Jin
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Shanbin Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Yang Hu
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Hongfei Zhang
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xiangrong Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China.
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Shimizu K, Kaneko K, Koyama D, Ohinata K. Soy-fortelin: A ghrelin sensitivity-enhancing peptide that stimulates food intake in aged mice. FASEB J 2023; 37:e22836. [PMID: 36856734 DOI: 10.1096/fj.202201482r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/24/2023] [Accepted: 02/13/2023] [Indexed: 03/02/2023]
Abstract
Ghrelin sensitivity is known to decrease with aging in mice and humans, and the decrease contributes to anorexia with aging. In this study, we discovered novel ghrelin sensitivity-enhancing peptides. Ghrelin sensitivity was evaluated by examining whether dipeptide samples enhanced the calcium response to ghrelin in the growth hormone secretagogue receptor-transfected cell line. First, dipeptides were screened using a 336-dipeptide library and we revealed that Ser-Tyr (SY) potentiated ghrelin sensitivity in particular. Based on the structure-activity relationship determined using the dipeptide library and comprehensive analysis of peptides in the chymotrypsin digest of soy β-conglycinin (β-CG), which enhanced ghrelin sensitivity, candidate peptides were narrowed down. Among the chemosynthesized peptides, we discovered that an undecapeptide, SLVNNDDRDSY, corresponding to β-CGα(267-277), stimulated ghrelin sensitivity in vitro. This peptide enhanced the orexigenic activity of ghrelin in C57BL/6 mice and stimulated food intake. Thus, we demonstrated that SLVNNDDRDSY stimulated ghrelin sensitivity in vitro and in vivo and named it "soy-fortelin". Moreover, orally administered soy-fortelin had a similar but smaller effect in the young C57BL/6 mice, whereas it strongly stimulated food intake in 2-year-old aged mice that exhibited high blood ghrelin levels and low ghrelin sensitivity. In conclusion, we discovered soy-fortelin as a novel peptide that enhances ghrelin sensitivity in vivo and in vitro and increases food intake in young and aged ghrelin-resistant mice. Soy-fortelin is the first food-derived peptide reported to enhance ghrelin sensitivity.
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Affiliation(s)
- Ken Shimizu
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kentaro Kaneko
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Daiki Koyama
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kousaku Ohinata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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Doyle ME, Premathilake HU, Yao Q, Mazucanti CH, Egan JM. Physiology of the tongue with emphasis on taste transduction. Physiol Rev 2023; 103:1193-1246. [PMID: 36422992 PMCID: PMC9942923 DOI: 10.1152/physrev.00012.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The tongue is a complex multifunctional organ that interacts and senses both interoceptively and exteroceptively. Although it is easily visible to almost all of us, it is relatively understudied and what is in the literature is often contradictory or is not comprehensively reported. The tongue is both a motor and a sensory organ: motor in that it is required for speech and mastication, and sensory in that it receives information to be relayed to the central nervous system pertaining to the safety and quality of the contents of the oral cavity. Additionally, the tongue and its taste apparatus form part of an innate immune surveillance system. For example, loss or alteration in taste perception can be an early indication of infection as became evident during the present global SARS-CoV-2 pandemic. Here, we particularly emphasize the latest updates in the mechanisms of taste perception, taste bud formation and adult taste bud renewal, and the presence and effects of hormones on taste perception, review the understudied lingual immune system with specific reference to SARS-CoV-2, discuss nascent work on tongue microbiome, as well as address the effect of systemic disease on tongue structure and function, especially in relation to taste.
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Affiliation(s)
- Máire E Doyle
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Hasitha U Premathilake
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Qin Yao
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Caio H Mazucanti
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Josephine M Egan
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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Azimzadeh M, Beheshti S. Down regulation of the hippocampal ghrelin receptor type-1a during electrical kindling-induced epileptogenesis. Epilepsy Res 2023; 189:107064. [PMID: 36516566 DOI: 10.1016/j.eplepsyres.2022.107064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/17/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022]
Abstract
Numerous studies have shown that the ghrelin hormone is involved in epileptic conditions. However, the profile of ghrelin or its functional receptor mRNAs in seizure-susceptible brain areas was not assessed during epileptogenesis. Here, we measured the expression levels of the hippocampal ghrelin or its receptor mRNAs during electrical kindling-induced epileptogenesis. The study was conducted on twenty adult male Wistar rats. One tri-polar and two uni-polar electrodes were stereotaxically implanted in the baso-lateral amygdala or skull surface, respectively. Animals were divided into four groups, consisting of two sham groups (sham1 and sham2), and two other groups, which were partially or fully kindled. After the establishment of partial or full kindling, the hippocampi of the animals and that of the corresponding sham groups were removed. A quantitative real-time PCR technique was used to measure the expression levels of ghrelin or its functional receptor mRNAs. The results indicated that the expression levels of ghrelin did not alter in either of the partially or fully kindled rats compared to the corresponding sham groups. Ghrelin receptor (ghrelinR) down regulated, significantly in the fully-kindled rats, compared to sham2 group. Meanwhile, the mRNA expression levels of ghrelinR did not change in partially-kindled rats compared to sham1 group. The outcomes of the current study highlight the crucial, unknown impact of the hippocampal ghrelinR through the development of electrical kindling epileptogenesis, and points out the importance of ghrelinR as a goal to adjust epileptogenic progression.
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Affiliation(s)
- Mansour Azimzadeh
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Siamak Beheshti
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
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Wang CH, Tseng CY, Hsu WL, Tzen JTC. Establishment of a Cell Line Stably Expressing the Growth Hormone Secretagogue Receptor to Identify Crocin as a Ghrelin Agonist. Biomolecules 2022; 12:biom12121813. [PMID: 36551241 PMCID: PMC9775697 DOI: 10.3390/biom12121813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022] Open
Abstract
The growth hormone secretagogue receptor-1a (GHSR1a) is the endogenous receptor for ghrelin. Activation of GHSR1a participates in many physiological processes including energy homeostasis and eating behavior. Due to its transitory half-life, the efficacy of ghrelin treatment in patients is restricted; hence the development of new adjuvant therapy is an urgent need. This study aimed to establish a cell line stably expressing GHSR1a, which could be employed to screen potential ghrelin agonists from natural compounds. First, by means of lentiviral transduction, the genome of a human HEK293T cell was modified, and a cell platform stably overexpressing GHSR1a was successfully established. In this platform, GHSR1a was expressed as a fusion protein tagged with mCherry, which allowed the monitoring of the dynamic cellular distribution of GHSR1a by fluorescent microscopy. Subsequently, the authenticity of the GHSR1a mediated signaling was further characterized by using ghrelin and teaghrelin, two molecules known to stimulate GHSR1a. The results indicated that both ghrelin and teaghrelin readily activated GHSR1a mediated signaling pathways, presumably via increasing phosphorylation levels of ERK. The specific GHSR1a signaling was further validated by using SP-analog, an antagonist of GHSR1a as well as using a cell model with the knockdown expression of GHSR1a. Molecular modeling predicted that crocin might be a potential ghrelin agonist, and this prediction was further confirmed by the established platform.
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Affiliation(s)
- Chia-Hao Wang
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 402, Taiwan
| | - Ching-Yu Tseng
- Graduate Institute of Microbiology and Public Health, National Chung-Hsing University, Taichung 402, Taiwan
| | - Wei-Li Hsu
- Graduate Institute of Microbiology and Public Health, National Chung-Hsing University, Taichung 402, Taiwan
- Correspondence: (W.-L.H.); (J.T.C.T.)
| | - Jason T. C. Tzen
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 402, Taiwan
- Correspondence: (W.-L.H.); (J.T.C.T.)
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11
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Kasprzak A, Adamek A. Role of the Ghrelin System in Colitis and Hepatitis as Risk Factors for Inflammatory-Related Cancers. Int J Mol Sci 2022; 23:ijms231911188. [PMID: 36232490 PMCID: PMC9569806 DOI: 10.3390/ijms231911188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/18/2022] [Accepted: 09/20/2022] [Indexed: 02/05/2023] Open
Abstract
It is not known exactly what leads to the development of colorectal cancer (CRC) and hepatocellular carcinoma (HCC), but there are specific risk factors that increase the probability of their occurrence. The unclear pathogenesis, too-late diagnosis, poor prognosis as a result of high recurrence and metastasis rates, and repeatedly ineffective therapy of both cancers continue to challenge both basic science and practical medicine. The ghrelin system, which is comprised of ghrelin and alternative peptides (e.g., obestatin), growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT), plays an important role in the physiology and pathology of the gastrointestinal (GI) tract. It promotes various physiological effects, including energy metabolism and amelioration of inflammation. The ghrelin system plays a role in the pathogenesis of inflammatory bowel diseases (IBDs), which are well known risk factors for the development of CRC, as well as inflammatory liver diseases which can trigger the development of HCC. Colitis-associated cancer serves as a prototype of inflammation-associated cancers. Little is known about the role of the ghrelin system in the mechanisms of transformation of chronic inflammation to low- and high-grade dysplasia, and, finally, to CRC. HCC is also associated with chronic inflammation and fibrosis arising from different etiologies, including alcoholic and nonalcoholic fatty liver diseases (NAFLD), and/or hepatitis B (HBV) and hepatitis C virus (HCV) infections. However, the exact role of ghrelin in the progression of the chronic inflammatory lesions into HCC is still unknown. The aim of this review is to summarize findings on the role of the ghrelin system in inflammatory bowel and liver diseases in order to better understand the impact of this system on the development of inflammatory-related cancers, namely CRC and HCC.
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Affiliation(s)
- Aldona Kasprzak
- Department of Histology and Embryology, University of Medical Sciences, Święcicki Street 6, 60-781 Poznań, Poland
- Correspondence: ; Tel.: +48-61-8546441; Fax: +48-61-8546440
| | - Agnieszka Adamek
- Department of Infectious Diseases, Hepatology and Acquired Immunodeficiencies, University of Medical Sciences, Szwajcarska Street 3, 61-285 Poznań, Poland
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Ringuet MT, Furness JB, Furness SGB. G protein-coupled receptor interactions and modification of signalling involving the ghrelin receptor, GHSR1a. J Neuroendocrinol 2022; 34:e13077. [PMID: 34931385 DOI: 10.1111/jne.13077] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/05/2021] [Indexed: 12/28/2022]
Abstract
The growth hormone secretagogue receptor 1a (GHSR1a) is intriguing because of its potential as a therapeutic target and its diverse molecular interactions. Initial studies of the receptor focused on the potential therapeutic ability for growth hormone (GH) release to reduce wasting in aging individuals, as well as food intake regulation for treatment of cachexia. Known roles of GHSR1a now extend to regulation of neurogenesis, learning and memory, gastrointestinal motility, glucose/lipid metabolism, the cardiovascular system, neuronal protection, motivational salience, and hedonic feeding. Ghrelin, the endogenous agonist of GHSR1a, is primarily located in the stomach and is absent from the central nervous system (CNS), including the spinal cord. However, ghrelin in the circulation does have access to a small number of CNS sites, including the arcuate nucleus, which is important in feeding control. At some sites, such as at somatotrophs, GHSR1a has high constitutive activity. Typically, ghrelin-dependent and constitutive GHSR1a activation occurs via Gαq/11 pathways. In vitro and in vivo data suggest that GHSR1a heterodimerises with multiple G protein-coupled receptors (GPCRs), including dopamine D1 and D2, serotonin 2C, orexin, oxytocin and melanocortin 3 receptors (MCR3), as well as the MCR3 accessory protein, MRAP2, providing possible mechanisms for its many physiological effects. In all cases, the receptor interaction changes downstream signalling and the responses to receptor agonists. This review discusses the signalling mechanisms of GHSR1a alone and in combination with other GPCRs, and explores the physiological consequences of GHSR1a coupling with other GPCRs.
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Affiliation(s)
- Mitchell Ty Ringuet
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia
| | - John Barton Furness
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
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13
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Effect of Ghrelin on the Cardiovascular System. BIOLOGY 2022; 11:biology11081190. [PMID: 36009817 PMCID: PMC9405061 DOI: 10.3390/biology11081190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/03/2022] [Accepted: 08/05/2022] [Indexed: 11/19/2022]
Abstract
Simple Summary Ghrelin is an octanoylated peptide that was initially isolated from rat and human stomachs in the process of searching for an endogenous ligand to the orphan growth hormone secretagogue receptor (GHS-R), a G-protein-coupled receptor. Exogenous or endogenous ghrelin secreted from the stomach binds to GHS-R on gastric vagal nerve terminals, and the signals are transmitted to the central nervous system via the vagal afferent nerve to facilitate growth hormone (GH) secretion, feeding, sympathetic inhibition, parasympathetic activation, and anabolic effects. Ghrelin also binds directly to the pituitary GHS-R and stimulates GH secretion. Ghrelin has beneficial effects on the cardiovascular system, including cardioprotective effects such as anti-heart failure, anti-arrhythmic, and anti-inflammatory actions, and it enhances vascular activity via GHS-R-dependent stimulation of GH/IGF-1 (insulin-like growth factor-1) and modulation of the autonomic nervous system. The anti-heart failure effects of ghrelin could be useful as a new therapeutic strategy for chronic heart failure. Abstract Ghrelin, an n-octanoyl-modified 28-amino-acid-peptide, was first discovered in the human and rat stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). Ghrelin-GHS-R1a signaling regulates feeding behavior and energy balance, promotes vascular activity and angiogenesis, improves arrhythmia and heart failure, and also protects against cardiovascular disease by suppressing cardiac remodeling after myocardial infarction. Ghrelin’s cardiovascular protective effects are mediated by the suppression of sympathetic activity; activation of parasympathetic activity; alleviation of vascular endothelial dysfunction; and regulation of inflammation, apoptosis, and autophagy. The physiological functions of ghrelin should be clarified to determine its pharmacological potential as a cardiovascular medication.
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Role of the Ghrelin System in Colorectal Cancer. Int J Mol Sci 2022; 23:ijms23105380. [PMID: 35628187 PMCID: PMC9141034 DOI: 10.3390/ijms23105380] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 02/06/2023] Open
Abstract
The ghrelin system contains several components (e.g., ghrelin with growing number of alternative peptides, growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT) and participates in regulation of a number of key processes of gastrointestinal (GI) tract cancer progression, including cell proliferation, migration, invasion, apoptosis, inflammation, and angiogenesis. However, its exact role in promoting or inhibiting cancer progression is still unclear. Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Molecular studies suggest an autocrine/paracrine mechanism for the secretion of ghrelin in colorectal carcinogenesis and its contribution to its initial stages. However, the signalling pathways of CRC development involving the ghrelin system are poorly understood. Potential mechanisms of colon carcinogenesis involving components of the ghrelin system were previously described in an animal model and in in vitro studies. However, the diagnostic–prognostic role of serum ghrelin concentrations, tissue expression, or genetic changes of this system in various stages of CRC progression remains an open case. Thus, the aim of this study is to discuss the role of the ghrelin system in colon carcinogenesis, diagnostics and CRC prognostics, as well as the results of studies on the use of ghrelin and its analogues in the therapy of CRC-related syndromes (e.g., cachexia and sarcopenia).
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15
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Karakoç Z, Topaloğlu U, Bayram B. Immunohistochemical distributions of leptin, ghrelin and obestatin hormones in bull and ram abomasum. Anat Histol Embryol 2022; 51:411-418. [PMID: 35288975 DOI: 10.1111/ahe.12801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/26/2022] [Accepted: 02/26/2022] [Indexed: 11/30/2022]
Abstract
In most mammals, leptin plays central and peripheral roles in a wide range of metabolic activities including feed consumption and digestion, energy expenditure and the regulation of carbohydrate-fat accumulation. Ghrelin is a strong appetite-stimulating hormone, while obestatin has the opposite effect of ghrelin. The latter is released during feeding, causing a sense of satiety. This study aimed to reveal if the metabolic hormones, as well as OB-R and GHS-R, were present in bull and ram abomasums. Streptavidin-biotin peroxidase method was implemented to determine the expressions and localizations of metabolic hormones and their receptors, and obestatin. Immunoreactivity for leptin and obestatin was present in the cytoplasms of luminal and glandular cells, while smooth muscle cells were immunoreactant for ghrelin, in both bull and ram abomasums. Immunoreactivity for OB-R was present in luminal and glandular cell, parietal cell cytoplasms, and blood vessels. Immunoreactivity for GHS-R, on the other hand, was found in glandular epithelial cell cytoplasms and parietal cell cytoplasms, in both bull and ram abomasums. Leptin immunoreactivity was detected in the glandular epithelial cells and stroma, and particularly in the parietal cells. Ghrelin immunoreactivity was not observed in glandular epithelial cells. Obestatin immunoreactivity was found intensely in the bull abomasum, while moderate immunoreactivity was observed in the ram abomasums. As such, leptin, ghrelin and obestatin hormones were expressed in bull and ram abomasums, similar to the abomasums of other species. It is believed that these hormones play important roles in the digestive system activities and the regulation of energy in bulls and rams.
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Affiliation(s)
- Zelal Karakoç
- Department of Laboratory Animals, Faculty of Veterinary Medicine, Dicle University, Diyarbakır, Turkey
| | - Uğur Topaloğlu
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Dicle University, Diyarbakır, Turkey
| | - Bayram Bayram
- Department of Veterinary Medicine, İdil Vocational School of Higher Education, Şırnak University, Şırnak, Turkey
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16
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Isokawa M. Ghrelin-O-acyltransferase (GOAT) acylates ghrelin in the hippocampus. VITAMINS AND HORMONES 2022; 118:369-392. [PMID: 35180934 DOI: 10.1016/bs.vh.2021.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Ghrelin is an appetite-stimulating peptide hormone and produced in the stomach. Serine 3 on ghrelin must be acylated by the lipid transferase known as Ghrelin-O-acyltransferase (GOAT) in order for the peptide to become physiologically-active and bind to the cognate receptor, growth hormone secretagogue receptor type 1a (GHSR1a). GHSR1a has been known to be expressed in the feeding center of the hypothalamus. However, the interest in GHSR1a increased dramatically among researchers in various biomedical fields when GHSR1a mRNA was found wide-spread in the brain including the hippocampus. Current understanding is that GHSR1a has multifaceted functions beyond the regulation of metabolism. In the blood, a nonacylated form of ghrelin (des-acyl ghrelin) exists in far greater amounts. Des-acyl ghrelin can cross the blood-brain barrier (BBB), but it cannot bind to GHSR1a in the brain. Thus, the identification of the source for acyl ghrelin in the brain became the critical and urgent quest. Here, we discuss the presence of GOAT in the hippocampus and its ability to acylate ghrelin locally within the hippocampus. We will show that GOAT is localized specifically at the base of the dentate granule cell layer in the rat and wild-type mouse, but not in the GHSR1a knockout mouse. This evidence points the possibility that the expression of GHSR1a may be a prerequisite for the synthesis of GOAT in the hippocampus. We will also show that: (1) the activation of GHSR1a by acyl ghrelin upregulates the cAMP and CREB phosphorylation, (2) amplifies the NMDA receptor-mediated synaptic transmission by phosphorylating GluN1 subunit at Ser896/897, and (3) activates Fyn kinase and induces GluN2B phosphorylation at Tyr1336. In summary, GOAT is a critical molecule that acts as the master switch in the initiation of ghrelin-induced hippocampal synapse and neuron plasticity.
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Affiliation(s)
- Masako Isokawa
- Department of Health and Biomedical Sciences, University of Texas Rio Grande Valley, Brownsville, TX, United States.
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17
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Azimzadeh M, Beheshti S. Antagonism of the ghrelin receptor type 1a in the rat brain induces status epilepticus in an electrical kindling model of epilepsy. Psychopharmacology (Berl) 2022; 239:479-487. [PMID: 34845505 DOI: 10.1007/s00213-021-06026-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
Studies have shown the anti-seizure properties of the ghrelin hormone in different models of epilepsy. Nevertheless, the role of the endogenous ghrelin is unknown in the electrical kindling model of epilepsy. In this study, we evaluated the effect of the antagonism of the ghrelin receptors in the brain of fully kindled rats. Adult male Wistar rats weighing 300 g were used. Animals were stereotaxically implanted with two uni-polar electrodes in the skull surface and a tri-polar electrode in the basolateral amygdala, and a guide cannula in the left lateral ventricle. Animals underwent a rapid kindling protocol. After showing three consecutive stages of five seizures, the animals were considered fully kindled. D-Lys-3-GHRP-6 (1, 50, and 100 μg/rat) was injected intracerebroventricularly (i.c.v.) in the kindled animals. Each rat was considered as its control and received a single dose of D-Lys-3-GHRP-6. Seizure parameters including after discharge duration (ADD), seizure stage (SS), stage four latency (S4L), and stage five duration (S5D) were recorded. The paired t test indicated a significant increase in seizure induction. D-Lys-3-GHRP-6 (1 μg/rat; i.c.v.) prolonged ADD in the kindled rats, significantly. D-Lys-3-GHRP-6 (50 and 100 μg/rat; i.c.v.) induced spontaneous seizures, which led to status epilepticus in the kindled rats. The results indicate that the antagonism of the ghrelin functional receptors prolongs seizures and induces status epilepticus in the kindling model of epilepsy, and propose that the endogenous ghrelin signaling has crucial antiepileptic properties.
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Affiliation(s)
- Mansour Azimzadeh
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Siamak Beheshti
- Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
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18
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Cifuentes L, Acosta A. Homeostatic regulation of food intake. Clin Res Hepatol Gastroenterol 2022; 46:101794. [PMID: 34481092 PMCID: PMC9721532 DOI: 10.1016/j.clinre.2021.101794] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 08/23/2021] [Indexed: 02/06/2023]
Abstract
Food intake and energy expenditure are key regulators of body weight. To regulate food intake, the brain must integrate physiological signals and hedonic cues. The brain plays an essential role in modulating the appropriate responses to the continuous update of the body energy-status by the peripheral signals and the neuronal pathways that generate the gut-brain axis. This regulation encompasses various steps involved in food consumption, include satiation, satiety, and hunger. It is important to have a comprehensive understanding of the mechanisms that regulate food consumption as well as to standardize the vocabulary for the steps involved. This review discusses the current knowledge of the regulation and the contribution peripheral and central signals at each step of the cycle to control appetite. We also highlight how food intake has been measured. The increasingly complex understanding of regulation and action mechanisms intervening in the gut-brain axis offers ambitious targets for new strategies to control appetite.
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19
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Masule MV, Rathod S, Agrawal Y, Patil CR, Nakhate KT, Ojha S, Goyal SN, Mahajan UB. Ghrelin mediated regulation of neurosynaptic transmitters in depressive disorders. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2022; 3:100113. [PMID: 35782191 PMCID: PMC9240712 DOI: 10.1016/j.crphar.2022.100113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/07/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Ghrelin is a peptide released by the endocrine cells of the stomach and the neurons in the arcuate nucleus of the hypothalamus. It modulates both peripheral and central functions. Although ghrelin has emerged as a potent stimulator of growth hormone release and as an orexigenic neuropeptide, the wealth of literature suggests its involvement in the pathophysiology of affective disorders including depression. Ghrelin exhibits a dual role through the advancement and reduction of depressive behavior with nervousness in the experimental animals. It modulates depression-related signals by forming neuronal networks with various neuropeptides and classical neurotransmitter systems. The present review emphasizes the integration and signaling of ghrelin with other neuromodulatory systems concerning depressive disorders. The role of ghrelin in the regulation of neurosynaptic transmission and depressive illnesses implies that the ghrelin system modulation can yield promising antidepressive therapies. Ghrelin is the orexigenic type of neuropeptide. It binds with the growth hormone secretagogue receptor (GHSR). GHSR is ubiquitously present in the various brain regions. Ghrelin is involved in the regulation of depression-related behavior. The review focuses on the neurotransmission and signaling of ghrelin in neuropsychiatric and depressive disorders.
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Affiliation(s)
- Milind V. Masule
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, 425405, Maharashtra, India
| | - Sumit Rathod
- Shri Vile Parle Kelavani Mandal's Institute of Pharmacy, Dhule, 424001, Maharashtra, India
| | - Yogeeta Agrawal
- Shri Vile Parle Kelavani Mandal's Institute of Pharmacy, Dhule, 424001, Maharashtra, India
| | - Chandragouda R. Patil
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, 425405, Maharashtra, India
| | - Kartik T. Nakhate
- Shri Vile Parle Kelavani Mandal's Institute of Pharmacy, Dhule, 424001, Maharashtra, India
| | - Shreesh Ojha
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Sameer N. Goyal
- Shri Vile Parle Kelavani Mandal's Institute of Pharmacy, Dhule, 424001, Maharashtra, India
- Corresponding author.
| | - Umesh B. Mahajan
- Department of Pharmacology, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, 425405, Maharashtra, India
- Corresponding author.
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20
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Lim Y, Lee V, Blanco A, Kelly SP, Unniappan S. Ion-poor water and dietary salt deprivation upregulate the ghrelinergic system in the goldfish (Carassius auratus). JOURNAL OF FISH BIOLOGY 2021; 99:1100-1109. [PMID: 34080192 DOI: 10.1111/jfb.14814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
Because the ghrelinergic system in teleost fishes is broadly expressed in organs that regulate appetite as well as those that contribute to the regulation of salt and water balance, we hypothesized that manipulating salt and water balance in goldfish (Carassius auratus) would modulate the ghrelinergic system. Goldfish were acclimated to either freshwater (FW) or ion-poor FW (IPW) and were fed either a control diet containing 1% NaCl or low-salt diet containing 0.1% NaCl. Endpoints of salt and water balance, i.e., serum Na+ and Cl- levels, muscle moisture content and organ-specific Na+ -K+ -ATPase (NKA) activity, were examined in conjunction with brain, gill and gut mRNA abundance of preproghrelin and its receptor, growth hormone secretagogue receptor (ghs-r). Acclimation of fish to IPW reduced serum osmolality and Cl- levels and elevated kidney NKA activity, while FW fish fed a low NaCl diet exhibited a modest reduction in muscle moisture content but otherwise no apparent osmoregulatory disturbance. In contrast, a combined treatment of IPW acclimation and low dietary NaCl content reduced serum osmolality and Cl- levels, elevated muscle moisture content and increased gill, kidney and intestinal NKA activity. This intensified response to the combined effects of water and dietary ion deprivation is consistent with an increased effort to enhance ion acquisition. In association with these latter observations, a significant upregulation of preproghrelin mRNA expression in brain and gut was observed. A significant increase in ghs-r mRNAs was also observed in the gill of goldfish acclimated to IPW alone but a reduction in dietary NaCl content did not impact the ghrelinergic system of goldfish in FW. The results support the hypothesis that the ghrelinergic system is modulated in response to manipulated salt and water balance. Whether the central and peripheral ghrelinergic system contributes to ionic homeostasis in goldfish currently remains unclear and warrants further research.
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Affiliation(s)
- YouRee Lim
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Vivienne Lee
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Ayelen Blanco
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Scott P Kelly
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Suraj Unniappan
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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21
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Micioni Di Bonaventura E, Botticelli L, Del Bello F, Giorgioni G, Piergentili A, Quaglia W, Cifani C, Micioni Di Bonaventura MV. Assessing the role of ghrelin and the enzyme ghrelin O-acyltransferase (GOAT) system in food reward, food motivation, and binge eating behavior. Pharmacol Res 2021; 172:105847. [PMID: 34438062 DOI: 10.1016/j.phrs.2021.105847] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/06/2023]
Abstract
The peripheral peptide hormone ghrelin is a powerful stimulator of food intake, which leads to body weight gain and adiposity in both rodents and humans. The hormone, thus, increases the vulnerability to obesity and binge eating behavior. Several studies have revealed that ghrelin's functions are due to its interaction with the growth hormone secretagogue receptor type 1a (GHSR1a) in the hypothalamic area; besides, ghrelin also promotes the reinforcing properties of hedonic food, acting at extra-hypothalamic sites and interacting with dopaminergic, cannabinoid, opioid, and orexin signaling. The hormone is primarily present in two forms in the plasma and the enzyme ghrelin O-acyltransferase (GOAT) allows the acylation reaction which causes the transformation of des-acyl-ghrelin (DAG) to the active form acyl-ghrelin (AG). DAG has been demonstrated to show antagonist properties; it is metabolically active, and counteracts the effects of AG on glucose metabolism and lipolysis, and reduces food consumption, body weight, and hedonic feeding response. Both peptides seem to influence the hypothalamic-pituitary-adrenal (HPA) axis and the corticosterone/cortisol level that drive the urge to eat under stressful conditions. These findings suggest that DAG and inhibition of GOAT may be targets for obesity and bingeing-related eating disorders and that AG/DAG ratio may be an important potential biomarker to assess the risk of developing maladaptive eating behaviors.
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Affiliation(s)
| | - Luca Botticelli
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 9, 62032 Camerino, Italy
| | - Fabio Del Bello
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Gianfabio Giorgioni
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Alessandro Piergentili
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Wilma Quaglia
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino, 1, 62032 Camerino, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 9, 62032 Camerino, Italy.
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22
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Role of the Endocannabinoid System in the Adipose Tissue with Focus on Energy Metabolism. Cells 2021; 10:cells10061279. [PMID: 34064024 PMCID: PMC8224009 DOI: 10.3390/cells10061279] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/12/2021] [Accepted: 05/15/2021] [Indexed: 12/15/2022] Open
Abstract
The endocannabinoid system is involved in a wide range of processes including the control of energy acquisition and expenditure. Endocannabinoids and their receptors are present in the central nervous system but also in peripheral tissues, notably the adipose tissues. The endocannabinoid system interacts with two main hormones regulating appetite, namely leptin and ghrelin. The inhibitory effect of the cannabinoid receptor 1 (CB1) antagonist rimonabant on fat mass suggested that the endocannabinoid system can also have a peripheral action in addition to its effect on appetite reduction. Thus, several investigations have focused on the peripheral role of the endocannabinoid system in the regulation of metabolism. The white adipose tissue stores energy as triglycerides while the brown adipose tissue helps to dissipate energy as heat. The endocannabinoid system regulates several functions of the adipose tissues to favor energy accumulation. In this review we will describe the presence of the endocannabinoid system in the adipose tissue. We will survey the role of the endocannabinoid system in the regulation of white and brown adipose tissue metabolism and how the eCB system participates in obesity and metabolic diseases.
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23
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Schalla MA, Taché Y, Stengel A. Neuroendocrine Peptides of the Gut and Their Role in the Regulation of Food Intake. Compr Physiol 2021; 11:1679-1730. [PMID: 33792904 DOI: 10.1002/cphy.c200007] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The regulation of food intake encompasses complex interplays between the gut and the brain. Among them, the gastrointestinal tract releases different peptides that communicate the metabolic state to specific nuclei in the hindbrain and the hypothalamus. The present overview gives emphasis on seven peptides that are produced by and secreted from specialized enteroendocrine cells along the gastrointestinal tract in relation with the nutritional status. These established modulators of feeding are ghrelin and nesfatin-1 secreted from gastric X/A-like cells, cholecystokinin (CCK) secreted from duodenal I-cells, glucagon-like peptide 1 (GLP-1), oxyntomodulin, and peptide YY (PYY) secreted from intestinal L-cells and uroguanylin (UGN) released from enterochromaffin (EC) cells. © 2021 American Physiological Society. Compr Physiol 11:1679-1730, 2021.
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Affiliation(s)
- Martha A Schalla
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Yvette Taché
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine, UCLA, Los Angeles, California, USA.,VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany
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24
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van Loenen MR, Geenen B, Arnoldussen IAC, Kiliaan AJ. Ghrelin as a prominent endocrine factor in stress-induced obesity. Nutr Neurosci 2020; 25:1413-1424. [PMID: 33373270 DOI: 10.1080/1028415x.2020.1863740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Objectives: Ghrelin acts on a variety of central- and peripheral organs causing an orexigenic effect, conclusively followed by increased caloric intake. Recent studies have indicated that ghrelin's function as an orexigenic agent does not entirely reflect the full functional properties of the peptide. Specifically, ghrelin regulates stress-hormone synthesis and secretion therewith affecting the stress-axis. The role of stress in the development of obesity has been extensively studied. However, the orexigenic and underlying stress-regulatory effect of ghrelin has not yet been further considered in the development of stress-induced obesity.Methods: Therefore, this review aims to accentuate the potential of ghrelin as a factor in the pathological development of stress-induced obesity.Results: In this review we discuss (1) the ghrelin-mediated intracellular cascades and elucidate the overall bioactivation of the peptide, and (2) the mechanisms of ghrelin signalling and regulation within the central nervous system and the gastro-intestinal system.Discussion: These biological processes will be ultimately discussed in relation to the pathogenesis of stress-induced obesity.
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Affiliation(s)
- Mark R van Loenen
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Preclinical Imaging Center PRIME, Nijmegen, Netherlands
| | - Bram Geenen
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Preclinical Imaging Center PRIME, Nijmegen, Netherlands
| | - Ilse A C Arnoldussen
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Preclinical Imaging Center PRIME, Nijmegen, Netherlands
| | - Amanda J Kiliaan
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Preclinical Imaging Center PRIME, Nijmegen, Netherlands
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25
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Gupta S, Mitra A. Heal the heart through gut (hormone) ghrelin: a potential player to combat heart failure. Heart Fail Rev 2020; 26:417-435. [PMID: 33025414 DOI: 10.1007/s10741-020-10032-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/21/2020] [Indexed: 12/17/2022]
Abstract
Ghrelin, a small peptide hormone (28 aa), secreted mainly by X/A-like cells of gastric mucosa, is also locally produced in cardiomyocytes. Being an orexigenic factor (appetite stimulant), it promotes release of growth hormone (GH) and exerts diverse physiological functions, viz. regulation of energy balance, glucose, and/or fat metabolism for body weight maintenance. Interestingly, administration of exogenous ghrelin significantly improves cardiac functions in CVD patients as well as experimental animal models of heart failure. Ghrelin ameliorates pathophysiological condition of the heart in myocardial infarction, cardiac hypertrophy, fibrosis, cachexia, and ischemia reperfusion injury. This peptide also exerts significant impact at the level of vasculature leading to lowering high blood pressure and reversal of endothelial dysfunction and atherosclerosis. However, the molecular mechanism of actions elucidating the healing effects of ghrelin on the cardiovascular system is still a matter of conjecture. Some experimental data indicate its beneficial effects via complex cellular cross talks between autonomic nervous system and cardiovascular cells, some other suggest more direct receptor-mediated molecular actions via autophagy or ionotropic regulation and interfering with apoptotic and inflammatory pathways of cardiomyocytes and vascular endothelial cells. Here, in this review, we summarise available recent data to encourage more research to find the missing links of unknown ghrelin receptor-mediated pathways as we see ghrelin as a future novel therapy in cardiovascular protection.
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Affiliation(s)
- Shreyasi Gupta
- Department of Zoology, Triveni Devi Bhalotia College, Raniganj, Paschim Bardhaman, 713347, India
| | - Arkadeep Mitra
- Department of Zoology, City College , 102/1, Raja Rammohan Sarani, Kolkata, 700009, India.
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26
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Jeon SG, Hong SB, Nam Y, Tae J, Yoo A, Song EJ, Kim KI, Lee D, Park J, Lee SM, Kim JI, Moon M. Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications. Ageing Res Rev 2019; 55:100945. [PMID: 31434007 DOI: 10.1016/j.arr.2019.100945] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022]
Abstract
Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.
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Acylated Ghrelin Renders Chemosensitive Ovarian Cancer Cells Resistant to Cisplatin Chemotherapy via Activation of the PI3K/Akt/mTOR Survival Pathway. Anal Cell Pathol (Amst) 2019; 2019:9627810. [PMID: 31360627 PMCID: PMC6644235 DOI: 10.1155/2019/9627810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/27/2019] [Accepted: 04/30/2019] [Indexed: 12/17/2022] Open
Abstract
This study investigated the effect of acylated synthetic ghrelin (AG) on the survival and proliferation of human chemosensitive ovarian cancer cells (A2780) and explored some mechanisms of action with a focus on the p53 apoptotic pathway and PI3K/Akt and NF-κB survival pathways. Human A2780 ovarian cancer cells were cultured with or without AG treatment in the presence or absence of cisplatin. In some cases, cisplatin+AG-treated cells were pre-incubated either with [D-Lys3]-GHRP-6, a ghrelin receptor antagonist, or with LY294002, a PI3K inhibitor. mRNA of ghrelin receptors(GHS-R1a and GHS-R1b), as well as, protein levels of GHS-R1a, were expressed abundantly in A2780 cells. AG treatment did not affect the mRNA and protein levels of GHS-R1a and GHS-R1b in both control and Cis-treated cells. However, while AG treatment had no effect on control cell viability, it significantly increased cell viability and proliferation and inhibited cell death in Cis-treated cells. In both control and Cis-treated cells, AG treatment significantly increased PI3K/Akt/mTOR signaling and enhanced the nuclear accumulation of NF-κB. Concomitantly, in both control and Cis-treated cells, AG significantly lowered the protein levels of p53, p-p53 (Ser16), PUMA, cytochrome C, and cleaved caspase-3. Interestingly, pre-incubating the cells with either [D-Lys3]-GHRP-6 or LY294002 completely abolished the above-mentioned effect of AG in both control and Cis-treated cells. In conclusion, the findings of this study show that AG promotes cell survival of the OC cells and renders them resistat to Cis therapy, an effect that is mediated by the activation of PI3K/Akt/mTOR and activation of NF-κB, and requires GHS-R1a.
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Serrenho D, Santos SD, Carvalho AL. The Role of Ghrelin in Regulating Synaptic Function and Plasticity of Feeding-Associated Circuits. Front Cell Neurosci 2019; 13:205. [PMID: 31191250 PMCID: PMC6546032 DOI: 10.3389/fncel.2019.00205] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 04/24/2019] [Indexed: 12/21/2022] Open
Abstract
Synaptic plasticity of the neuronal circuits associated with feeding behavior is regulated by peripheral signals as a response to changes in the energy status of the body. These signals include glucose, free fatty acids, leptin and ghrelin and are released into circulation, being able to reach the brain. Ghrelin, a small peptide released from the stomach, is an orexigenic hormone produced in peripheral organs, and its action regulates food intake, body weight and glucose homeostasis. Behavioral studies show that ghrelin is implicated in the regulation of both hedonic and homeostatic feeding and of cognition. Ghrelin-induced synaptic plasticity has been described in neuronal circuits associated with these behaviors. In this review, we discuss the neuromodulatory mechanisms induced by ghrelin in regulating synaptic plasticity in three main neuronal circuits previously associated with feeding behaviors, namely hypothalamic (homeostatic feeding), ventral tegmental (hedonic and motivational feeding) and hippocampal (cognitive) circuits. Given the central role of ghrelin in regulating feeding behaviors, and the altered ghrelin levels associated with metabolic disorders such as obesity and anorexia, it is of paramount relevance to understand the effects of ghrelin on synaptic plasticity of neuronal circuits associated with feeding behaviors.
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Affiliation(s)
- Débora Serrenho
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal.,PhD Program in Experimental Biology and Biomedicine (PDBEB), University of Coimbra, Coimbra, Portugal
| | - Sandra D Santos
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Ana Luísa Carvalho
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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Huang HJ, Chen XR, Han QQ, Wang J, Pilot A, Yu R, Liu Q, Li B, Wu GC, Wang YQ, Yu J. The protective effects of Ghrelin/GHSR on hippocampal neurogenesis in CUMS mice. Neuropharmacology 2019; 155:31-43. [PMID: 31103617 DOI: 10.1016/j.neuropharm.2019.05.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 04/27/2019] [Accepted: 05/12/2019] [Indexed: 12/18/2022]
Abstract
Ghrelin is an orexigenic hormone that also plays an important role in mood disorders. Our previous studies demonstrated that ghrelin administration could protect against depression-like behaviors of chronic unpredictable mild stress (CUMS) in rodents. However, the mechanism related to the effect of ghrelin on CUMS mice has yet to be revealed. This article shows that ghrelin (5 nmol/kg/day for 2 weeks, i.p.) decreased depression-like behaviors induced by CUMS and increased hippocampal integrity (neurogenesis and spine density) measured via Ki67, 5-bromo-2-deoxyuridine (BrdU), doublecortin (DCX) labeling and Golgi-cox staining, which were decreased under CUMS. The behavioral phenotypes of Growth hormone secretagogue receptor (Ghsr)-null and wild type (WT) mice were evaluated under no stress condition and after CUMS exposure to determine the effect of Ghsr knockout on the behavioral phenotypes and stress susceptibility of mice. Ghsr-null mice exhibited depression-like behaviors under no stress condition. CUMS induced similar depression- and anxiety-like behavioral manifestations in both Ghsr-null and WT mice. A similar pattern of behavioral changes was observed after hippocampal GHSR knockdown. Additionally, both Ghsr knockout as well as CUMS exhibited deleterious effects on neurogenesis and spine density in the dentate gyrus (DG). Besides, CCK8 assay and 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assay showed that ghrelin has a proliferative effect on primary cultured hippocampal neural stem cells (NSCs) and this proliferation was blocked by D-Lys3-GHRP-6 (DLS, the antagonist of GHSR, 100 μM) pretreatment. Ghrelin-induced proliferation is associated with the inhibition of G1 arrest, and this inhibition was blocked by LY294002 (specific inhibitor of PI3K, 20 μM). Furthermore, the in vivo data displayed that LY294002 (50 nmol, i.c.v.) can significantly block the antidepressant-like action of exogenous ghrelin treatment. All these results suggest that ghrelin/GHSR signaling maintains the integrity of hippocampus and has an inherent neuroprotective effect whether facing stress or not.
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Affiliation(s)
- Hui-Jie Huang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Xiao-Rong Chen
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Qiu-Qin Han
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Jing Wang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Adam Pilot
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Rui Yu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Qiong Liu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, 200032, China
| | - Bing Li
- Center Laboratories, Jinshan Hospital of Fudan University, Shanghai, 201508, China
| | - Gen-Cheng Wu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yan-Qing Wang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jin Yu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
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30
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Al Massadi O, Nogueiras R, Dieguez C, Girault JA. Ghrelin and food reward. Neuropharmacology 2019; 148:131-138. [PMID: 30615902 DOI: 10.1016/j.neuropharm.2019.01.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/02/2019] [Accepted: 01/02/2019] [Indexed: 12/14/2022]
Abstract
Food intake is tightly regulated by homeostatic and reward mechanisms and the adequate function of both is necessary for the proper maintenance of energy balance. Ghrelin impacts on these two levels to induce feeding. In this review, we present the actions of ghrelin in food reward, including their dependence on other relevant modulators implicated in the motivational aspects of feeding, including dopamine, opioid peptides, and endocannabinoids. We also describe the interaction between brain areas involved in homeostatic regulation of feeding and the reward system, with a special emphasis on the role of arcuate nucleus melanocortins and lateral hypothalamus orexins in ghrelin function. Finally, we briefly discuss the actions of ghrelin in food reward in obesity. We propose that new insights into the mechanism of action of ghrelin in the rewarding and motivational control of food intake will help to understand food-related disorders including obesity and anorexia.
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Affiliation(s)
- Omar Al Massadi
- Inserm UMR-S 839, 75005, Paris, France; Sorbonne Université, Sciences and Engineering Faculty, 75005 Paris, France; Institut du Fer a Moulin, 75005, Paris, France.
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Carlos Dieguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Jean-Antoine Girault
- Inserm UMR-S 839, 75005, Paris, France; Sorbonne Université, Sciences and Engineering Faculty, 75005 Paris, France; Institut du Fer a Moulin, 75005, Paris, France
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31
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Ramirez VT, van Oeffelen WEPA, Torres-Fuentes C, Chruścicka B, Druelle C, Golubeva AV, van de Wouw M, Dinan TG, Cryan JF, Schellekens H. Differential functional selectivity and downstream signaling bias of ghrelin receptor antagonists and inverse agonists. FASEB J 2018; 33:518-531. [PMID: 30020830 DOI: 10.1096/fj.201800655r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ghrelin receptor [growth hormone secretagogue receptor (GHSR)-1a] represents a promising pharmacologic target for the treatment of metabolic disorders, including obesity and cachexia, via central appetite modulation. The GHSR-1a has a complex pharmacology, highlighted by G-protein-dependent and -independent downstream signaling pathways and high basal constitutive activity. The functional selectivity and signaling bias of many GHSR-1a-specific ligands has not been fully characterized. In this study, we investigated the pharmacologic properties of ghrelin, MK-0677, L692,585, and [d-Lys3]-growth hormone-releasing peptide-6 (Dlys), JMV2959, and [d-Arg(1),d-Phe(5),d-Trp(7, 9),Leu(11)]-substance P (SP-analog). We investigated their effect on basal GHSR-1a constitutive signaling, ligand-directed downstream GHSR-1a signaling, functional selectivity, and signaling bias. Dlys behaved as a partial antagonist with a strong bias toward GHSR-1a-β-arrestin signaling, whereas JMV2959 acted as a full unbiased GHSR-1a antagonist. Moreover, the SP-analog behaved as an inverse agonist increasing G-protein-dependent signaling, but only at high concentrations, whereas, at low concentrations, the SP-analog attenuated β-arrestin-dependent signaling. Considering the limited success in the clinical development of GHSR-1a-targeted drugs so far, these findings provide a novel insight into the pharmacologic characteristics of GHSR-1a ligands and their signaling bias, which has important implications in the design of novel, more selective GHSR-1a ligands with predictable functional outcome and selectivity for preclinical and clinical drug development.-Ramirez, V. T., van Oeffelen, W. E. P. A., Torres-Fuentes, C., Chruścicka, B., Druelle, C., Golubeva, A. V., van de Wouw, M., Dinan, T. G., Cryan, J. F., Schellekens, H. Differential functional selectivity and downstream signaling bias of ghrelin receptor antagonists and inverse agonists.
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Affiliation(s)
- Valerie T Ramirez
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Cristina Torres-Fuentes
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Barbara Chruścicka
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Clementine Druelle
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Anna V Golubeva
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Marcel van de Wouw
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Psychiatry, University College Cork, Cork, Ireland; and
| | - John F Cryan
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Food for Health Ireland, University College Cork, Cork, Ireland
| | - Harriët Schellekens
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Food for Health Ireland, University College Cork, Cork, Ireland
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32
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Mandal A, Prabhavalkar KS, Bhatt LK. Gastrointestinal hormones in regulation of memory. Peptides 2018; 102:16-25. [PMID: 29466709 DOI: 10.1016/j.peptides.2018.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/16/2022]
Abstract
The connection between the gastrointestinal hormones and the brain has been established many years ago. This relation is termed the gut-brain axis (GBA). The GBA is a bidirectional communication which not only regulates gastrointestinal homeostasis but is also linked with higher emotional and cognitive functions. Hypothalamus plays a critical role in the regulation of energy metabolism, nutrient partitioning and control of feeding behaviors. Various gut hormones are released inside the gastrointestinal tract on food intake. These hormones act peripherally and influence the different responses of the tissues to the food intake, but do also have effects on the brain. The hypothalamus, in turn, integrates visceral function with limbic system structures such as hippocampus, amygdala, and cerebral cortex. The hippocampus has been known for its involvement in the cognitive function and the modulation of synaptic plasticity. This review aims to establish the role of various gut hormones in learning and memory, through the interaction of various receptors in the hippocampus. Understanding their role in memory can also aid in finding novel therapeutic strategies for the treatment of the neurological disorders associated with memory dysfunctions.
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Affiliation(s)
- Anwesha Mandal
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India
| | - Kedar S Prabhavalkar
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India.
| | - Lokesh K Bhatt
- Department of Pharmacology, SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India
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33
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Sominsky L, Hodgson DM, McLaughlin EA, Smith R, Wall HM, Spencer SJ. Linking Stress and Infertility: A Novel Role for Ghrelin. Endocr Rev 2017; 38:432-467. [PMID: 28938425 DOI: 10.1210/er.2016-1133] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 07/24/2017] [Indexed: 12/23/2022]
Abstract
Infertility affects a remarkable one in four couples in developing countries. Psychological stress is a ubiquitous facet of life, and although stress affects us all at some point, prolonged or unmanageable stress may become harmful for some individuals, negatively impacting on their health, including fertility. For instance, women who struggle to conceive are twice as likely to suffer from emotional distress than fertile women. Assisted reproductive technology treatments place an additional physical, emotional, and financial burden of stress, particularly on women, who are often exposed to invasive techniques associated with treatment. Stress-reduction interventions can reduce negative affect and in some cases to improve in vitro fertilization outcomes. Although it has been well-established that stress negatively affects fertility in animal models, human research remains inconsistent due to individual differences and methodological flaws. Attempts to isolate single causal links between stress and infertility have not yet been successful due to their multifaceted etiologies. In this review, we will discuss the current literature in the field of stress-induced reproductive dysfunction based on animal and human models, and introduce a recently unexplored link between stress and infertility, the gut-derived hormone, ghrelin. We also present evidence from recent seminal studies demonstrating that ghrelin has a principal role in the stress response and reward processing, as well as in regulating reproductive function, and that these roles are tightly interlinked. Collectively, these data support the hypothesis that stress may negatively impact upon fertility at least in part by stimulating a dysregulation in ghrelin signaling.
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Affiliation(s)
- Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
| | - Deborah M Hodgson
- School of Psychology, Faculty of Science and IT, The University of Newcastle, New South Wales 2308, Australia
| | - Eileen A McLaughlin
- School of Biological Sciences, Faculty of Science, The University of Auckland, Auckland 1010, New Zealand.,School of Environmental & Life Sciences, Faculty of Science and IT, The University of Newcastle, New South Wales 2308, Australia
| | - Roger Smith
- Mothers and Babies Research Centre, Hunter Medical Research Institute, Lookout Road, New Lambton Heights, New South Wales 2305, Australia.,Priority Research Centre in Reproductive Science, The University of Newcastle, New South Wales 2308, Australia
| | - Hannah M Wall
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
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34
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Chen SR, Chen H, Zhou JJ, Pradhan G, Sun Y, Pan HL, Li DP. Ghrelin receptors mediate ghrelin-induced excitation of agouti-related protein/neuropeptide Y but not pro-opiomelanocortin neurons. J Neurochem 2017; 142:512-520. [DOI: 10.1111/jnc.14080] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Shao-Rui Chen
- Department of Anesthesiology and Perioperative Medicine; Center for Neuroscience and Pain Research; The University of Texas MD Anderson Cancer Center; Houston Texas USA
| | - Hong Chen
- Department of Anesthesiology and Perioperative Medicine; Center for Neuroscience and Pain Research; The University of Texas MD Anderson Cancer Center; Houston Texas USA
| | - Jing-Jing Zhou
- Department of Anesthesiology and Perioperative Medicine; Center for Neuroscience and Pain Research; The University of Texas MD Anderson Cancer Center; Houston Texas USA
| | - Geetali Pradhan
- Department of Pediatrics; USDA/ARS Children's Nutrition Research Center; Baylor College of Medicine; Houston Texas USA
| | - Yuxiang Sun
- Department of Pediatrics; USDA/ARS Children's Nutrition Research Center; Baylor College of Medicine; Houston Texas USA
- Department of Nutrition and Food Science (NFSC); Texas A&M University; College Station Texas USA
| | - Hui-Lin Pan
- Department of Anesthesiology and Perioperative Medicine; Center for Neuroscience and Pain Research; The University of Texas MD Anderson Cancer Center; Houston Texas USA
| | - De-Pei Li
- Department of Anesthesiology and Perioperative Medicine; Center for Neuroscience and Pain Research; The University of Texas MD Anderson Cancer Center; Houston Texas USA
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35
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Luo QQ, Zhou YF, Chen MYJ, Liu L, Ma J, Zhang MW, Zhang FL, Ke Y, Qian ZM. Fasting up-regulates ferroportin 1 expression via a Ghrelin/GHSR/MAPK signaling pathway. J Cell Physiol 2017; 233:30-37. [PMID: 28338217 DOI: 10.1002/jcp.25931] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/22/2017] [Indexed: 01/18/2023]
Abstract
The significant positive correlation between ghrelin and iron and hepcidin levels in the plasma of children with iron deficiency anemia prompted us to hypothesize that ghrelin may affect iron metabolism. Here, we investigated the effects of fasting or ghrelin on the expression of hepcidin, ferroportin 1 (Fpn1), transferrin receptor 1 (TfR1), ferritin light chain (Ft-L) proteins, and ghrelin, and also hormone secretagogue receptor 1 alpha (GHSR1α) and ghrelin O-acyltransferase (GOAT) mRNAs in the spleen and/or macrophage. We demonstrated that fasting induces a significant increase in the expression of ghrelin, GHSR1α, GOAT, and hepcidin mRNAs, as well as Ft-L and Fpn1 but not TfR1 proteins in the spleens of mice in vivo. Similar to the effects of fasting on the spleen, ghrelin induced a significant increase in the expression of Ft-L and Fpn1 but not TfR1 proteins in macrophages in vitro. In addition, ghrelin was found to induce a significant enhancement in phosphorylation of ERK as well as translocation of pERK from the cytosol to nuclei. Furthermore, the increased pERK and Fpn1 induced by ghrelin was demonstrated to be preventable by pre-treatment with either GHSR1α antagonist or pERK inhibitor. Our findings support the hypothesis that fasting upregulates Fpn1 expression, probably via a ghrelin/GHSR/MAPK signaling pathway.
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Affiliation(s)
- Qian-Qian Luo
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China.,Pharmacological Evaluation and Research Center, Shanghai Institute of PharmaceuticalIndustry, Shanghai, China.,Department of Biochemistry, Institute for Nautical Medicine, Nantong University, Nantong, China
| | - Yu-Fu Zhou
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China
| | - Mesona Yung-Jin Chen
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China
| | - Li Liu
- Pharmacological Evaluation and Research Center, Shanghai Institute of PharmaceuticalIndustry, Shanghai, China
| | - Juan Ma
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China
| | - Meng-Wan Zhang
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China
| | - Fa-Li Zhang
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China
| | - Ya Ke
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
| | - Zhong-Ming Qian
- Laboratory of Neuropharmacology, Fudan University School of Pharmacy, Shanghai, China
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Attenuating the Biologic Drive for Weight Regain Following Weight Loss: Must What Goes Down Always Go Back Up? Nutrients 2017; 9:nu9050468. [PMID: 28481261 PMCID: PMC5452198 DOI: 10.3390/nu9050468] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 04/26/2017] [Accepted: 04/28/2017] [Indexed: 01/01/2023] Open
Abstract
Metabolic adaptations occur with weight loss that result in increased hunger with discordant simultaneous reductions in energy requirements—producing the so-called energy gap in which more energy is desired than is required. The increased hunger is associated with elevation of the orexigenic hormone ghrelin and decrements in anorexigenic hormones. The lower total daily energy expenditure with diet-induced weight loss results from (1) a disproportionately greater decrease in circulating leptin and resting metabolic rate (RMR) than would be predicted based on the decline in body mass, (2) decreased thermic effect of food (TEF), and (3) increased energy efficiency at work intensities characteristic of activities of daily living. These metabolic adaptations can readily promote weight regain. While more experimental research is needed to identify effective strategies to narrow the energy gap and attenuate weight regain, some factors contributing to long-term weight loss maintenance have been identified. Less hunger and greater satiation have been associated with higher intakes of protein and dietary fiber, and lower glycemic load diets. High levels of physical activity are characteristic of most successful weight maintainers. A high energy flux state characterized by high daily energy expenditure and matching energy intake may attenuate the declines in RMR and TEF, and may also result in more accurate regulation of energy intake to match daily energy expenditure.
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Jiao Q, Du X, Li Y, Gong B, Shi L, Tang T, Jiang H. The neurological effects of ghrelin in brain diseases: Beyond metabolic functions. Neurosci Biobehav Rev 2016; 73:98-111. [PMID: 27993602 DOI: 10.1016/j.neubiorev.2016.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 12/01/2016] [Accepted: 12/10/2016] [Indexed: 02/08/2023]
Abstract
Ghrelin, a peptide released by the stomach that plays a major role in regulating energy metabolism, has recently been shown to have effects on neurobiological behaviors. Ghrelin enhances neuronal survival by reducing apoptosis, alleviating inflammation and oxidative stress, and accordingly improving mitochondrial function. Ghrelin also stimulates the proliferation, differentiation and migration of neural stem/progenitor cells (NS/PCs). Additionally, the ghrelin is benefit for the recovery of memory, mood and cognitive dysfunction after stroke or traumatic brain injury. Because of its neuroprotective and neurogenic roles, ghrelin may be used as a therapeutic agent in the brain to combat neurodegenerative disease. In this review, we highlight the pre-clinical evidence and the proposed mechanisms underlying the role of ghrelin in physiological and pathological brain function.
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Affiliation(s)
- Qian Jiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China; Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Qingdao University, Qingdao, China.
| | - Xixun Du
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China; Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Qingdao University, Qingdao, China.
| | - Yong Li
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China; Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Qingdao University, Qingdao, China.
| | - Bing Gong
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China.
| | - Limin Shi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China; Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Qingdao University, Qingdao, China.
| | - Tingting Tang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China; Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Qingdao University, Qingdao, China.
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, China; Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Qingdao University, Qingdao, China.
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Abstract
G protein-coupled receptors are the largest family of targets for current therapeutics. The classic model of their activation was binary, where agonist binding induced an active conformation and subsequent downstream signaling. Subsequently, the revised concept of biased agonism emerged, where different ligands at the same G protein-coupled receptor selectively activate one downstream pathway versus another. Advances in understanding the mechanism of biased agonism have led to the development of novel ligands, which have the potential for improved therapeutic and safety profiles. In this review, we summarize the theory and most recent breakthroughs in understanding biased signaling, examine recent laboratory investigations concerning biased ligands across different organ systems, and discuss the promising clinical applications of biased agonism.
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Fujitsuka N, Asakawa A, Morinaga A, Amitani MS, Amitani H, Katsuura G, Sawada Y, Sudo Y, Uezono Y, Mochiki E, Sakata I, Sakai T, Hanazaki K, Yada T, Yakabi K, Sakuma E, Ueki T, Niijima A, Nakagawa K, Okubo N, Takeda H, Asaka M, Inui A. Increased ghrelin signaling prolongs survival in mouse models of human aging through activation of sirtuin1. Mol Psychiatry 2016; 21:1613-1623. [PMID: 26830139 PMCID: PMC5078860 DOI: 10.1038/mp.2015.220] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 12/01/2015] [Accepted: 12/15/2015] [Indexed: 02/07/2023]
Abstract
Caloric restriction (CR) is known to retard aging and delay functional decline as well as the onset of diseases in most organisms. Ghrelin is secreted from the stomach in response to CR and regulates energy metabolism. We hypothesized that in CR ghrelin has a role in protecting aging-related diseases. We examined the physiological mechanisms underlying the ghrelin system during the aging process in three mouse strains with different genetic and biochemical backgrounds as animal models of accelerated or normal human aging. The elevated plasma ghrelin concentration was observed in both klotho-deficient and senescence-accelerated mouse prone/8 (SAMP8) mice. Ghrelin treatment failed to stimulate appetite and prolong survival in klotho-deficient mice, suggesting the existence of ghrelin resistance in the process of aging. However, ghrelin antagonist hastened death and ghrelin signaling potentiators rikkunshito and atractylodin ameliorated several age-related diseases with decreased microglial activation in the brain and prolonged survival in klotho-deficient, SAMP8 and aged ICR mice. In vitro experiments, the elevated sirtuin1 (SIRT1) activity and protein expression through the cAMP-CREB pathway was observed after ghrelin and ghrelin potentiator treatment in ghrelin receptor 1a-expressing cells and human umbilical vein endothelial cells. Furthermore, rikkunshito increased hypothalamic SIRT1 activity and SIRT1 protein expression of the heart in the all three mouse models of aging. Pericarditis, myocardial calcification and atrophy of myocardial and muscle fiber were improved by treatment with rikkunshito. Ghrelin signaling may represent one of the mechanisms activated by CR, and potentiating ghrelin signaling may be useful to extend health and lifespan.
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Affiliation(s)
- N Fujitsuka
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan,Tsumura Research Laboratories, Tsumura, Ibaraki, Japan
| | - A Asakawa
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - A Morinaga
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - M S Amitani
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - H Amitani
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - G Katsuura
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Y Sawada
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan
| | - Y Sudo
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan
| | - Y Uezono
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan
| | - E Mochiki
- Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - I Sakata
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - T Sakai
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - K Hanazaki
- Department of Surgery, Kochi Medical School, Kochi, Japan
| | - T Yada
- Department of Physiology, Jichi Medical University School of Medicine, Tochigi, Japan
| | - K Yakabi
- Department of Gastroenterology and Hepatology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - E Sakuma
- Department of Integrative Anatomy, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - T Ueki
- Department of Integrative Anatomy, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - A Niijima
- Department of Physiology, Niigata University School of Medicine, Niigata, Japan
| | - K Nakagawa
- Pathophysiology and Therapeutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - N Okubo
- Pathophysiology and Therapeutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - H Takeda
- Pathophysiology and Therapeutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan,Hokkaido University Hospital Gastroenterological Medicine, Sapporo, Japan
| | - M Asaka
- Cancer Preventive Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - A Inui
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan,Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan. E-mail:
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Distinct phosphorylation sites on the ghrelin receptor, GHSR1a, establish a code that determines the functions of ß-arrestins. Sci Rep 2016; 6:22495. [PMID: 26935831 PMCID: PMC4776146 DOI: 10.1038/srep22495] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 02/15/2016] [Indexed: 01/14/2023] Open
Abstract
The growth hormone secretagogue receptor, GHSR1a, mediates the biological activities
of ghrelin, which includes the secretion of growth hormone, as well as the
stimulation of appetite, food intake and maintenance of energy homeostasis. Mapping
phosphorylation sites on GHSR1a and knowledge of how these sites control specific
functional consequences unlocks new strategies for the development of therapeutic
agents targeting individual functions. Herein, we have identified the
phosphorylation of different sets of sites within GHSR1a which engender distinct
functionality of ß-arrestins. More specifically, the
Ser362, Ser363 and Thr366 residues
at the carboxyl-terminal tail were primarily responsible for ß-arrestin
1 and 2 binding, internalization and ß-arrestin-mediated proliferation
and adipogenesis. The Thr350 and Ser349 are not
necessary for ß-arrestin recruitment, but are involved in the
stabilization of the GHSR1a-ß-arrestin complex in a manner that
determines the ultimate cellular consequences of ß-arrestin signaling.
We further demonstrated that the mitogenic and adipogenic effect of ghrelin were
mainly dependent on the ß-arrestin bound to the phosphorylated GHSR1a.
In contrast, the ghrelin function on GH secretion was entirely mediated by G protein
signaling. Our data is consistent with the hypothesis that the phosphorylation
pattern on the C terminus of GHSR1a determines the signaling and physiological
output.
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Bai RX, Wang WP, Zhao PW, Li CB. Ghrelin attenuates the growth of HO-8910 ovarian cancer cells through the ERK pathway. Braz J Med Biol Res 2016; 49:S0100-879X2016000300602. [PMID: 26840702 PMCID: PMC4763821 DOI: 10.1590/1414-431x20155043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/16/2015] [Indexed: 12/16/2022] Open
Abstract
Ovarian cancer is one of the most common causes of death from gynecologic tumors and is an important public health issue. Ghrelin is a recently discovered bioactive peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR). Several studies have identified the protective effects of ghrelin on the mammalian reproductive system. However, little research has been done on the effects of ghrelin on ovarian cancer cells, and the underlying mechanisms of these effects. We sought to understand the potential involvement of mitogen-activated protein kinases (MAPKs) in ghrelin-mediated inhibition of growth of the ovarian line HO-8910. We applied different concentrations of ghrelin and an inhibitor of the ghrelin receptor (D-Lys3-GHRP-6) to HO-8910 cells and observed the growth rate of cells and changes in phosphorylation of the MAPKs ERK1/2, JNK and p38. We discovered that ghrelin-induced apoptosis of HO-8910 cells was though phosphorylated ERK1/2, and that this phosphorylation (as well as p90rsk phosphorylation) was mediated by the GHSR. The ERK1/2 pathway is known to play an essential part in the ghrelin-mediated apoptosis of HO-8910 cells. Hence, our study suggests that ghrelin inhibits the growth of HO-8910 cells primarily through the GHSR/ERK pathway.
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Affiliation(s)
- R X Bai
- Department of Clinical Laboratory, Inner Mongolia People's Hospital, Hohhot, China
| | - W P Wang
- Graduate College, Inner Mongolia Medical University, Hohhot, China
| | - P W Zhao
- Microbiology and Immunology Laboratory, School of Basic Medical Science, Inner Mongolia Medical University, Hohhot, China
| | - C B Li
- School of Basic Medical Science, Inner Mongolia Medical University, Hohhot, China
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42
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Muniz BG, Isokawa M. Ghrelin receptor activity amplifies hippocampal N-methyl-d-aspartate receptor-mediated postsynaptic currents and increases phosphorylation of the GluN1 subunit at Ser896 and Ser897. Eur J Neurosci 2015; 42:3045-53. [PMID: 26490687 DOI: 10.1111/ejn.13107] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 12/31/2022]
Abstract
Although ghrelin and its cognate receptor growth hormone secretagogue receptor (GHSR1a) are highly localized in the hypothalamic nuclei for the regulation of metabolic states and feeding, GHSR1a is also highly localized in the hippocampus, suggesting its involvement in extra-hypothalamic functions. Indeed, exogenous application of ghrelin has been reported to improve hippocampal learning and memory. However, the underlying mechanism of ghrelin regulation of hippocampal functions is poorly understood. Here, we report ghrelin-promoted phosphorylation of GluN1 and amplified N-methyl-d-aspartate receptor (NMDAR)-mediated excitatory postsynaptic currents in the CA1 pyramidal cells of the hippocampus in slice preparations. The ghrelin-induced responses were sensitive to a GHSR1a antagonist and inverse agonist, and were absent in GHSR1a homozygous knock-out mice. These results indicated that activation of GHSR1a was critical in the ghrelin-induced enhancement of the NMDAR function. Interestingly, heterozygous mouse hippocampi were also insensitive to ghrelin treatment, suggesting that a slight reduction in the availability of GHSR1a may be sufficient to negate the effect of ghrelin on GluN1 phosphorylation and NMDAR channel activities. In addition, NMDAR-mediated spike currents, which are of dendritic origin, were blocked by the GHSR1a antagonist, suggesting the presence of GHSR1a on the pyramidal cell dendrites in physical proximity to NMDAR. Together with our findings on the localization of GHSR1a in the CA1 region of the hippocampus, which was shown by fluorescent ghrelin binding, immunoreactivity, and enhanced green fluorescent protein reporter gene expression, we conclude that the activation of GHSR1a favours rapid modulation of the NMDAR-mediated glutamatergic synaptic transmission by phosphorylating GluN1 in the hippocampus.
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Affiliation(s)
- Brandon G Muniz
- Department of Health and Biomedical Sciences, The University of Texas Rio Grande Valley, One West University Boulevard, Brownsville, TX, 78520, USA
| | - Masako Isokawa
- Department of Health and Biomedical Sciences, The University of Texas Rio Grande Valley, One West University Boulevard, Brownsville, TX, 78520, USA
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43
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Mirzaei Bavil F, Alipour MR, Keyhanmanesh R, Alihemmati A, Ghiyasi R, Mohaddes G. Ghrelin Decreases Angiogenesis, HIF-1α and VEGF Protein Levels in Chronic Hypoxia in Lung Tissue of Male Rats. Adv Pharm Bull 2015; 5:315-20. [PMID: 26504752 DOI: 10.15171/apb.2015.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/14/2014] [Accepted: 10/18/2014] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Hypoxia is a condition of decreased availability of oxygen. When cells are exposed to a low oxygen environment, they impel the hypoxia responses to adapt to new situation. The hypoxia response leads to the activation of various cellular signaling pathways. The aim of this study was to evaluate the effect of ghrelin on angiogenesis, Hypoxia-Inducible-Factor-1α (HIF-1) and Vascular endothelial growth factor (VEGF) levels in normobaric hypoxia situation. METHODS Twenty four animals were divided into 4 groups (n=6): control (C), ghrelin (Gh), hypoxia (H), and hypoxic animals that received ghrelin (H+Gh). 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 showed that hypoxia significantly (p<0.05) increased angiogenesis without any significant changes on HIF-1 and VEGF levels, whereas ghrelin significantly (p<0.05) decreased angiogenesis, expression of HIF-1 and VEGF in this condition. Ghrelin administration did not show any significant changes in normal conditions. CONCLUSION Ghrelin had no effect on angiogenesis, expression of HIF-1 and VEGF in normal oxygen conditions but it reduced angiogenesis process in lung tissue with reducing the level of HIF and VEGF in hypoxic condition. Therefore, effect of ghrelin on angiogenesis could be related to blood oxygen level.
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Affiliation(s)
- Fariba Mirzaei Bavil
- Tuberculosis and Lung Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Reza Alipour
- Tuberculosis and Lung Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Rana Keyhanmanesh
- Tuberculosis and Lung Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Alihemmati
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Rafigheh Ghiyasi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Gisou Mohaddes
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Luque RM, Sampedro-Nuñez M, Gahete MD, Ramos-Levi A, Ibáñez-Costa A, Rivero-Cortés E, Serrano-Somavilla A, Adrados M, Culler MD, Castaño JP, Marazuela M. In1-ghrelin, a splice variant of ghrelin gene, is associated with the evolution and aggressiveness of human neuroendocrine tumors: Evidence from clinical, cellular and molecular parameters. Oncotarget 2015; 6:19619-33. [PMID: 26124083 PMCID: PMC4637309 DOI: 10.18632/oncotarget.4316] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 06/06/2015] [Indexed: 01/27/2023] Open
Abstract
Ghrelin system comprises a complex family of peptides, receptors (GHSRs), and modifying enzymes [e.g. ghrelin-O-acyl-transferase (GOAT)] that control multiple pathophysiological processes. Aberrant alternative splicing is an emerging cancer hallmark that generates altered proteins with tumorigenic capacity. Indeed, In1-ghrelin and truncated-GHSR1b splicing variants can promote development/progression of certain endocrine-related cancers. Here, we determined the expression levels of key ghrelin system components in neuroendocrine tumor (NETs) and explored their potential functional role. Twenty-six patients with NETs were prospectively/retrospectively studied [72 samples from primary and metastatic tissues (30 normal/42 tumors)] and clinical data were obtained. The role of In1-ghrelin in aggressiveness was studied in vitro using NET cell lines (BON-1/QGP-1). In1-ghrelin, GOAT and GHSR1a/1b expression levels were elevated in tumoral compared to normal/adjacent tissues. Moreover, In1-ghrelin, GOAT, and GHSR1b expression levels were positively correlated within tumoral, but not within normal/adjacent samples, and were higher in patients with progressive vs. with stable/cured disease. Finally, In1-ghrelin increased aggressiveness (e.g. proliferation/migration) of NET cells. Altogether, our data strongly suggests a potential implication of ghrelin system in the pathogenesis and/or clinical outcome of NETs, and warrant further studies on their possible value for the future development of molecular biomarkers with diagnostic/prognostic/therapeutic value.
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Affiliation(s)
- Raul M Luque
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba Hospital Universitario Reina Sofía, Instituto Maimónides de Investigación Biomèdica de Córdoba (IMIBIC), Campus de Excelencia Internacional Agroalimentario (ceiA3), CIBER Fisiopatología de la Obesidad y Nutricón (CIBERObn), Córdoba, España
| | - Miguel Sampedro-Nuñez
- Servicio de Endocrinología y Nutrición, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Instituto de Investigación Sanitaria Princesa, Madrid, España
| | - Manuel D Gahete
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba Hospital Universitario Reina Sofía, Instituto Maimónides de Investigación Biomèdica de Córdoba (IMIBIC), Campus de Excelencia Internacional Agroalimentario (ceiA3), CIBER Fisiopatología de la Obesidad y Nutricón (CIBERObn), Córdoba, España
| | - Ana Ramos-Levi
- Servicio de Endocrinología y Nutrición, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Instituto de Investigación Sanitaria Princesa, Madrid, España
| | - Alejandro Ibáñez-Costa
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba Hospital Universitario Reina Sofía, Instituto Maimónides de Investigación Biomèdica de Córdoba (IMIBIC), Campus de Excelencia Internacional Agroalimentario (ceiA3), CIBER Fisiopatología de la Obesidad y Nutricón (CIBERObn), Córdoba, España
| | - Esther Rivero-Cortés
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba Hospital Universitario Reina Sofía, Instituto Maimónides de Investigación Biomèdica de Córdoba (IMIBIC), Campus de Excelencia Internacional Agroalimentario (ceiA3), CIBER Fisiopatología de la Obesidad y Nutricón (CIBERObn), Córdoba, España
| | - Ana Serrano-Somavilla
- Servicio de Endocrinología y Nutrición, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Instituto de Investigación Sanitaria Princesa, Madrid, España
| | - Magdalena Adrados
- Servicio de Patología, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Instituto de Investigación Sanitaria Princesa, Madrid, España
| | | | - Justo P Castaño
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba Hospital Universitario Reina Sofía, Instituto Maimónides de Investigación Biomèdica de Córdoba (IMIBIC), Campus de Excelencia Internacional Agroalimentario (ceiA3), CIBER Fisiopatología de la Obesidad y Nutricón (CIBERObn), Córdoba, España
| | - Mónica Marazuela
- Servicio de Endocrinología y Nutrición, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Instituto de Investigación Sanitaria Princesa, Madrid, España
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Magdaleno-Méndez A, Domínguez B, Rodríguez-Andrade A, Barrientos-Morales M, Cervantes-Acosta P, Hernández-Beltrán A, González-Ramírez R, Felix R. Ghrelin increases growth hormone production and functional expression of NaV1.1 and Na V1.2 channels in pituitary somatotropes. Endocrine 2015; 48:929-36. [PMID: 25151402 DOI: 10.1007/s12020-014-0392-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/11/2014] [Indexed: 12/19/2022]
Abstract
A variety of ion channels are expressed in the plasma membrane of somatotropes within the anterior pituitary gland. Modification of these channels is linked to intracellular Ca2+ levels and therefore to hormone secretion. Previous investigations have shown that the gut-derived orexigenic peptide hormone ghrelin and synthetic GH-releasing peptides (GHRPs) stimulate release of growth hormone (GH) and increase the number of functional voltage-gated Ca2+ and Na+ channels in the membrane of clonal GC somatotropes. Here, we reveal that chronic treatment with ghrelin and its synthetic analog GHRP-6 also increases GH release from bovine pituitary somatotropes in culture, and that this action is associated with a significant increase in Na+ macroscopic current. Consistent with this, Na+ current blockade with tetrodotoxin (TTX) abolished the ghrelin- and GHRP-6-induced increase in GH release. Furthermore, semi-quantitative and real-time RT-PCR analysis revealed an upregulation in the transcript levels of GH, as well as of NaV1.1 and NaV1.2, two isoforms of TTX-sensitive Na+ channels expressed in somatotropes, after treatment with ghrelin or GHRP-6. These findings improve our knowledge on (i) the cellular mechanisms involved in the control of GH secretion, (ii) the molecular diversity of Na+ channels in pituitary somatotropes, and (iii) the regulation of GH and Na+ channel gene expression by ghrelin and GHRPs.
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Affiliation(s)
- Adasue Magdaleno-Méndez
- Laboratory of Cell Biology, School of Veterinary Medicine and Animal Science, University of Veracruz, Circunvalación esquina Yáñez s/n, C.P. 91710, Veracruz, Mexico
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Mani BK, Walker AK, Lopez Soto EJ, Raingo J, Lee CE, Perelló M, Andrews ZB, Zigman JM. Neuroanatomical characterization of a growth hormone secretagogue receptor-green fluorescent protein reporter mouse. J Comp Neurol 2014; 522:3644-66. [PMID: 24825838 PMCID: PMC4142102 DOI: 10.1002/cne.23627] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 12/15/2022]
Abstract
Growth hormone secretagogue receptor (GHSR) 1a is the only molecularly identified receptor for ghrelin, mediating ghrelin-related effects on eating, body weight, and blood glucose control, among others. The expression pattern of GHSR within the brain has been assessed previously by several neuroanatomical techniques. However, inherent limitations to these techniques and the lack of reliable anti-GHSR antibodies and reporter rodent models that identify GHSR-containing neurons have prevented a more comprehensive functional characterization of ghrelin-responsive neurons. Here we have systematically characterized the brain expression of an enhanced green fluorescence protein (eGFP) transgene controlled by the Ghsr promoter in a recently reported GHSR reporter mouse. Expression of eGFP in coronal brain sections was compared with GHSR mRNA expression detected in the same sections by in situ hybridization histochemistry. eGFP immunoreactivity was detected in several areas, including the prefrontal cortex, insular cortex, olfactory bulb, amygdala, and hippocampus, which showed no or low GHSR mRNA expression. In contrast, eGFP expression was low in several midbrain regions and in several hypothalamic nuclei, particularly the arcuate nucleus, where robust GHSR mRNA expression has been well-characterized. eGFP expression in several brainstem nuclei showed high to moderate degrees of colocalization with GHSR mRNA labeling. Further quantitative PCR and electrophysiological analyses of eGFP-labeled hippocampal cells confirmed faithful expression of eGFP within GHSR-containing, ghrelin-responsive neurons. In summary, the GHSR-eGFP reporter mouse model may be a useful tool for studying GHSR function, particularly within the brainstem and hippocampus; however, it underrepresents GHSR expression in nuclei within the hypothalamus and midbrain.
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Affiliation(s)
- Bharath K. Mani
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Angela K. Walker
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Eduardo J. Lopez Soto
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Buenos Aires, Argentina
| | - Jesica Raingo
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Buenos Aires, Argentina
| | - Charlotte E. Lee
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Mario Perelló
- Laboratory of Electrophysiology, Multidisciplinary Institute of Cell Biology, Buenos Aires, Argentina
| | - Zane B. Andrews
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Jeffrey M. Zigman
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
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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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48
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Evron T, Peterson SM, Urs NM, Bai Y, Rochelle LK, Caron MG, Barak LS. G Protein and β-arrestin signaling bias at the ghrelin receptor. J Biol Chem 2014; 289:33442-55. [PMID: 25261469 DOI: 10.1074/jbc.m114.581397] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The G protein-coupled ghrelin receptor GHSR1a is a potential pharmacological target for treating obesity and addiction because of the critical role ghrelin plays in energy homeostasis and dopamine-dependent reward. GHSR1a enhances growth hormone release, appetite, and dopamine signaling through G(q/11), G(i/o), and G(12/13) as well as β-arrestin-based scaffolds. However, the contribution of individual G protein and β-arrestin pathways to the diverse physiological responses mediated by ghrelin remains unknown. To characterize whether a signaling bias occurs for GHSR1a, we investigated ghrelin signaling in a number of cell-based assays, including Ca(2+) mobilization, serum response factor response element, stress fiber formation, ERK1/2 phosphorylation, and β-arrestin translocation, utilizing intracellular second loop and C-tail mutants of GHSR1a. We observed that GHSR1a and β-arrestin rapidly form metastable plasma membrane complexes following exposure to an agonist, but replacement of the GHSR1a C-tail by the tail of the vasopressin 2 receptor greatly stabilizes them, producing complexes observable on the plasma membrane and also in endocytic vesicles. Mutations of the contiguous conserved amino acids Pro-148 and Leu-149 in the GHSR1a intracellular second loop generate receptors with a strong bias to G protein and β-arrestin, respectively, supporting a role for conformation-dependent signaling bias in the wild-type receptor. Our results demonstrate more balance in GHSR1a-mediated ERK signaling from G proteins and β-arrestin but uncover an important role for β-arrestin in RhoA activation and stress fiber formation. These findings suggest an avenue for modulating drug abuse-associated changes in synaptic plasticity via GHSR1a and indicate the development of GHSR1a-biased ligands as a promising strategy for selectively targeting downstream signaling events.
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Affiliation(s)
| | | | | | - Yushi Bai
- From the Departments of Cell Biology
| | | | - Marc G Caron
- From the Departments of Cell Biology, Neurobiology, and Medicine, Duke University, Medical Center, Durham, North Carolina 27710
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49
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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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50
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Callaghan B, Furness JB. Novel and Conventional Receptors for Ghrelin, Desacyl-Ghrelin, and Pharmacologically Related Compounds. Pharmacol Rev 2014; 66:984-1001. [DOI: 10.1124/pr.113.008433] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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