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Tanrıverdi LH, Özhan O, Ulu A, Yıldız A, Ateş B, Vardı N, Acet HA, Parlakpinar H. Activation of the Mas receptors by AVE0991 and MrgD receptor using alamandine to limit the deleterious effects of Ang II-induced hypertension. Fundam Clin Pharmacol 2023; 37:60-74. [PMID: 36117326 DOI: 10.1111/fcp.12829] [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: 07/04/2022] [Revised: 08/16/2022] [Accepted: 09/06/2022] [Indexed: 01/27/2023]
Abstract
The MrgD receptor agonist, alamandine (ALA) and Mas receptor agonist, AVE0991 have recently been identified as protective components of the renin-angiotensin system. We evaluated the effects of ALA and AVE0991 on cardiovascular function and remodeling in angiotensin (Ang) II-induced hypertension in rats. Sprague Dawley rats were subject to 4-week subcutaneous infusions of Ang II (80 ng/kg/min) or saline after which they were treated with ALA (50 μg/kg), AVE0991 (576 μg/kg), or ALA+AVE0991 during the last 2 weeks. Systolic blood pressure (SBP) and heart rate (HR) values were recorded with tail-cuff plethysmography at 1, 15, and 29 days post-treatment. After euthanization, the heart and thoracic aorta were removed for further analysis and vascular responses. SBP significantly increased in the Ang II group when compared to the control group. Furthermore, Ang II also caused an increase in cardiac and aortic cyclophilin-A (CYP-A), monocyte chemoattractant protein-1 (MCP-1), and cardiomyocyte degeneration but produced a decrease in vascular relaxation. HR, matrix metalloproteinase-2 and -9, NADPH oxidase-4, and lysyl oxidase levels were comparable among groups. ALA, AVE0991, and the drug combination produced antihypertensive effects and alleviated vascular responses. The inflammatory and oxidative stress related to cardiac MCP-1 and CYP-A levels decreased in the Ang II+ALA+AVE0991 group. Vascular but not cardiac angiotensin-converting enzyme-2 levels decreased with Ang II administration but were similar to the Ang II+ALA+AVE0991 group. Our experimental data showed the combination of ALA and AVE0991 was found beneficial in Ang II-induced hypertension in rats by reducing SBP, oxidative stress, inflammation, and improving vascular responses.
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Affiliation(s)
| | - Onural Özhan
- Department of Medical Pharmacology, Faculty of Medicine, İnönü University, Malatya, Türkiye
| | - Ahmet Ulu
- Biochemistry and Biomaterials Research Laboratory, Department of Chemistry, Faculty of Science, İnönü University, Malatya, Türkiye
| | - Azibe Yıldız
- Department of Histology and Medical Embryology, Faculty of Medicine, İnönü University, Malatya, Türkiye
| | - Burhan Ateş
- Biochemistry and Biomaterials Research Laboratory, Department of Chemistry, Faculty of Science, İnönü University, Malatya, Türkiye
| | - Nigar Vardı
- Department of Histology and Medical Embryology, Faculty of Medicine, İnönü University, Malatya, Türkiye
| | - Hacı Ahmet Acet
- Department of Medical Pharmacology, Faculty of Medicine, İnönü University, Malatya, Türkiye
| | - Hakan Parlakpinar
- Department of Medical Pharmacology, Faculty of Medicine, İnönü University, Malatya, Türkiye
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2
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Meanti R, Licata M, Rizzi L, Bresciani E, Molteni L, Coco S, Locatelli V, Omeljaniuk RJ, Torsello A. Protective Effects of Hexarelin and JMV2894 in a Human Neuroblastoma Cell Line Expressing the SOD1-G93A Mutated Protein. Int J Mol Sci 2023; 24:ijms24020993. [PMID: 36674509 PMCID: PMC9863688 DOI: 10.3390/ijms24020993] [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: 09/27/2022] [Revised: 12/22/2022] [Accepted: 12/22/2022] [Indexed: 01/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable motor neuron disease whose etiology remains unresolved; nonetheless, mutations of superoxide dismutase 1 (SOD1) have been associated with several variants of ALS. Currently available pharmacologic interventions are only symptomatic and palliative in effect; therefore, there is a pressing demand for more effective drugs. This study examined potential therapeutic effects of growth hormone secretagogues (GHSs), a large family of synthetic compounds, as possible candidates for the treatment of ALS. Human neuroblastoma cells expressing the SOD1-G93A mutated protein (SH-SY5Y SOD1G93A cells) were incubated for 24 h with H2O2 (150 µM) in the absence, or presence, of GHS (1 µM), in order to study the protective effect of GHS against increased oxidative stress. The two GHSs examined in this study, hexarelin and JMV2894, protected cells from H2O2-induced cytotoxicity by activating molecules that regulate apoptosis and promote cell survival processes. These findings suggest the possibility of developing new GHS-based anti-oxidant and neuroprotective drugs with improved therapeutic potential. Further investigations are required for the following: (i) to clarify GHS molecular mechanisms of action, and (ii) to envisage the development of new GHSs that may be useful in ALS therapy.
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Affiliation(s)
- Ramona Meanti
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | - Martina Licata
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | - Laura Rizzi
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
- Correspondence: ; Tel.: +39-02-6448-8224
| | - Elena Bresciani
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | - Laura Molteni
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | - Silvia Coco
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | - Vittorio Locatelli
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
| | | | - Antonio Torsello
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Monza, Italy
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Hexarelin Modulation of MAPK and PI3K/Akt Pathways in Neuro-2A Cells Inhibits Hydrogen Peroxide-Induced Apoptotic Toxicity. Pharmaceuticals (Basel) 2021; 14:ph14050444. [PMID: 34066741 PMCID: PMC8150489 DOI: 10.3390/ph14050444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 11/17/2022] Open
Abstract
Hexarelin, a synthetic hexapeptide, exerts cyto-protective effects at the mitochondrial level in cardiac and skeletal muscles, both in vitro and in vivo, may also have important neuroprotective bioactivities. This study examined the inhibitory effects of hexarelin on hydrogen peroxide (H2O2)-induced apoptosis in Neuro-2A cells. Neuro-2A cells were treated for 24 h with various concentrations of H2O2 or with the combination of H2O2 and hexarelin following which cell viability and nitrite (NO2−) release were measured. Cell morphology was also documented throughout and changes arising were quantified using Image J skeleton and fractal analysis procedures. Apoptotic responses were evaluated by Real-Time PCR (caspase-3, caspase-7, Bax, and Bcl-2 mRNA levels) and Western Blot (cleaved caspase-3, cleaved caspase-7, MAPK, and Akt). Our results indicate that hexarelin effectively antagonized H2O2-induced damage to Neuro-2A cells thereby (i) improving cell viability, (ii) reducing NO2− release and (iii) restoring normal morphologies. Hexarelin treatment also reduced mRNA levels of caspase-3 and its activation, and modulated mRNA levels of the BCL-2 family. Moreover, hexarelin inhibited MAPKs phosphorylation and increased p-Akt protein expression. In conclusion, our results demonstrate neuroprotective and anti-apoptotic effects of hexarelin, suggesting that new analogues could be developed for their neuroprotective effects.
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Piotrowska A, Chmielewska M, Andrzejewski W, Dziegiel P, Podhorska-Okolow M. Influence of Angiotensin II on cell viability and apoptosis in rat renal proximal tubular epithelial cells in in vitro studies. J Renin Angiotensin Aldosterone Syst 2020; 21:1470320320949850. [PMID: 32962526 PMCID: PMC7649907 DOI: 10.1177/1470320320949850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Introduction: Angiotensin II (Ang II) is multifunctional peptide that plays an important role in blood pressure regulation and maintenance electrolyte homeostasis. It shows biological effects by activating two main receptors: AT1 and AT2. The aim of the present work was to investigate the effect of Ang II on NRK-52E cells in in vitro studies. Furthermore, an attempt was made to determine the effectiveness of the AT1 and AT2 receptor blocker activity (respectively, losartan and PD123319). Methods: The study was carried out using adherent NRK-52E cell line. Immunofluorescence and Western Blot method were used to confirm the presence of AT1 and AT2 receptors in the cells. The SRB and MTT tests showed decrease in the viability of NRK-52E cells incubated with Ang II in comparison to the control (without Ang II). Results: The blockade of the AT1 receptor caused an increase in cell viability in comparison to cells incubated with Ang II only. The blockade of AT2 receptor also triggered statistically significant increase in cell viability in comparison with cells only exposed to Ang II. Combined administration of blockers for both receptors (losartan and PD123319) decreased Ang II cytotoxicity against NRK-52E cell line. The apoptosis was only observed in cells incubated with Ang II in comparison with control cells. However, simultaneous use of both blockers caused statistically significant decrease in apoptosis. Conclusions: The result of our study indicates that Ang II causes damaging effect on NRK-52E cells by directing them to programmed cell death. It seems that not only does the AT2 receptor itself play an important role in the induction of apoptosis, but also its interaction with AT1 receptor does as well.
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Affiliation(s)
- Aleksandra Piotrowska
- Division of Histology and Embryology, Department of Human Morphology and Embryology, Wroclaw Medical University, Poland
| | - Magdalena Chmielewska
- Amphibian Biology Group, Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wroclaw, Poland
| | - Waldemar Andrzejewski
- Department of Physiotherapy, Wroclaw University School of Physical Education, Poland
| | - Piotr Dziegiel
- Division of Histology and Embryology, Department of Human Morphology and Embryology, Wroclaw Medical University, Poland.,Department of Physiotherapy, Wroclaw University School of Physical Education, Poland
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Raghay K, Akki R, Bensaid D, Errami M. Ghrelin as an anti-inflammatory and protective agent in ischemia/reperfusion injury. Peptides 2020; 124:170226. [PMID: 31786283 DOI: 10.1016/j.peptides.2019.170226] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 11/27/2019] [Accepted: 11/27/2019] [Indexed: 02/06/2023]
Abstract
Ischemia/reperfusion (I/R) continue to be the most frequent cause of damaged tissues. Injured tissues resulted from the first ischemic insult, which is determined by the interruption in the blood supply, followed by subsequent impairment induced by reperfusion. In addition, ischemia-reperfusion injury is mediated by tumor necrosis factor (TNF) and other cytokines that activate complements and proteases responsible for free radical production. However, earlier studies have reported the protective roles of bioactive peptides during ischemia reperfusion injury. In fact, ghrelin is a peptide hormone discovered since 1999 as GH secretagogue and its production was identified in gastric X/A-like endocrine cells in rats and P/D1 type cells in humans. To date, this peptide receives growing attention due to its pleiotropic action in the organism and its role in maintaining energy homeostasis. Ghrelin is also involved in stress responses, assuming a modulatory action on immune pathways. Previous studies have identified many other functions related to an anti-inflammatory role in ischemia reperfusion injury. Under these challenging conditions, studies described acylated and unacylated ghrelin in activation and/or inhibition processes related to ischemia-reperfusion injury. The aim of this article is to provide a minireview about ghrelin mechanisms involved in the proinflammatory response of I/R injury. However, the regulatory processes of ghrelin in this pathologic event are still very limited and warrant further investigation.
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Affiliation(s)
- K Raghay
- Department of Biology, Faculty of Sciences, Abdelmalek Essaadi University, Tetouan, Morocco.
| | - R Akki
- Department of Biology, Faculty of Sciences, Abdelmalek Essaadi University, Tetouan, Morocco.
| | - D Bensaid
- Department of Biology, Faculty of Sciences, Abdelmalek Essaadi University, Tetouan, Morocco.
| | - M Errami
- Department of Biology, Faculty of Sciences, Abdelmalek Essaadi University, Tetouan, Morocco.
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Zhong S, Liu Y, Wang F, Wu Z, Zhao S. Microcystin-LR induced oxidative stress, inflammation, and apoptosis in alveolar type II epithelial cells of ICR mice in vitro. Toxicon 2019; 174:19-25. [PMID: 31874178 DOI: 10.1016/j.toxicon.2019.12.152] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 11/28/2019] [Accepted: 12/19/2019] [Indexed: 12/22/2022]
Abstract
Previous studies have shown that microcystin-LR (MC-LR) produced by toxic cyanobacterial blooms could inflict damage to the lung. However, the mechanisms underlying MC-induced pulmonary toxicity are not fully described. In this study, the primary' fetal alveolar type II epithelial cells (AEC II) from ICR mice, which are involved in formation of bioactive component of pulmonary epithelium and secretion of pulmonary surfactants, were exposed to MC-LR at different concentrations (0, 0.625, 1.25, 2.5, 5, 10, 20 μg/mL) for different time (12, 24, 36 h). Results showed that the viabilities of AEC II exposed to 10 and 20 μg MC-LR/mL were significantly decreased compared with the control group. Furthermore, MC-LR exposure resulted in overproduction of reactive oxygen species (ROS) and induced a significant reduction in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Expressions of apoptosis-related proteins including bax, cyt-c, and caspase-9 were significantly up-regulated by exposure to 2.5, 5, 10, or 20 μg MC-LR/mL. When exposed to 5, 10, or 20 μg MC-LR/mL, expressions of proteins involved in inflammatory, p-65 and iNOS were significantly greater than those of the controls. In conclusion, inflammation and apoptosis might be responsible for MC-LR-induced pulmonary injury.
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Affiliation(s)
- Shengzheng Zhong
- School of Public Health, Anhui Medical University, Hefei, 230032, China
| | - Ying Liu
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - Fang Wang
- School of Public Health, Anhui Medical University, Hefei, 230032, China
| | - Zaiwei Wu
- School of Public Health, Anhui Medical University, Hefei, 230032, China
| | - Sujuan Zhao
- School of Public Health, Anhui Medical University, Hefei, 230032, China.
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7
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Cheng XL, Ding F, Wang DP, Zhou L, Cao JM. Hexarelin attenuates atherosclerosis via inhibiting LOX-1-NF-κB signaling pathway-mediated macrophage ox-LDL uptake in ApoE -/- mice. Peptides 2019; 121:170122. [PMID: 31386895 DOI: 10.1016/j.peptides.2019.170122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 12/12/2022]
Abstract
Growth hormone secretagogues (GHS) have been proved to exert protective effects on the cardiovascular system, while their potential beneficial effects on macrophages in atherosclerosis (AS) are rarely been clarified. This study aimed to demonstrate whether hexarelin, a synthetic peptidyl GHS, can suppress AS progression via regulating the function of macrophages. AS was induced by chronic (3 months) feeding with high lipid diet in ApoE-/- mice. Mice were treated either with hexarelin (100 μg/kg s.c., q.d. for 3 months) (AS + Hex group) or saline (AS group). Age-matched C57BL/6 J mice were used as normal controls. AS and related signaling molecules in aortic tissues and RAW264.7 macrophages were identified with variant methods including histological staining, ELISA, western blotting, confocal microscopy and flow cytometry. AS significantly developed in ApoE-/- mice fed with high lipids diet. Hexarelin decreased serum TC, TG and LDL-c, increased serum HDL-c and attenuated the formation of atherosclerotic plaques and neointima compared with the AS group. Hexarelin decreased the aortic expressions of CD68 and LOX-1 which were elevated in the AS group. Hexarelin increased GHSR expression, suppressed ox-LDL uptake and LOX-1 expression and inhibited nuclear factor-kappa B (NF-κB) activation both in the aorta of ApoE-/- mice and in RAW264.7 macrophages. We conclude that hexarelin effectively attenuates AS progression in ApoE-/- mice by modulating circulatory lipids profile and inhibiting macrophage ox-LDL uptake via suppressing the LOX-1-NF-κB signaling pathway. The study supports the perspective of hexarelin as an anti-AS drug.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, Differentiation, Myelomonocytic/genetics
- Antigens, Differentiation, Myelomonocytic/metabolism
- Aorta/drug effects
- Aorta/metabolism
- Aorta/pathology
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Atherosclerosis/drug therapy
- Atherosclerosis/etiology
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Biological Transport/drug effects
- Cholesterol, HDL/blood
- Cholesterol, LDL/blood
- Diet, High-Fat/adverse effects
- Disease Models, Animal
- Gene Expression Regulation
- Lipoproteins, LDL/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NF-kappa B/antagonists & inhibitors
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Oligopeptides/pharmacology
- Plaque, Atherosclerotic/drug therapy
- Plaque, Atherosclerotic/etiology
- Plaque, Atherosclerotic/genetics
- Plaque, Atherosclerotic/metabolism
- RAW 264.7 Cells
- Receptors, Ghrelin/genetics
- Receptors, Ghrelin/metabolism
- Scavenger Receptors, Class E/antagonists & inhibitors
- Scavenger Receptors, Class E/genetics
- Scavenger Receptors, Class E/metabolism
- Signal Transduction
- Triglycerides/blood
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Affiliation(s)
- Xiu-Li Cheng
- Department of Clinical Laboratory, Tianjin Key Laboratory of Cerebral Vessels and Neural Degeneration, Tianjin Huanhu Hospital, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Fan Ding
- Office of Scientific R&D, Tsinghua University, Beijing, China
| | - De-Ping Wang
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Lan Zhou
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Ji-Min Cao
- Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China.
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8
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Growth Hormone Secretagogues and the Regulation of Calcium Signaling in Muscle. Int J Mol Sci 2019; 20:ijms20184361. [PMID: 31491959 PMCID: PMC6769538 DOI: 10.3390/ijms20184361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/02/2019] [Accepted: 09/03/2019] [Indexed: 12/22/2022] Open
Abstract
Growth hormone secretagogues (GHS) are a family of synthetic molecules, first discovered in the late 1970s for their ability to stimulate growth hormone (GH) release. Many effects of GHS are mediated by binding to GHS-R1a, the receptor for the endogenous hormone ghrelin, a 28-amino acid peptide isolated from the stomach. Besides endocrine functions, both ghrelin and GHS are endowed with some relevant extraendocrine properties, including stimulation of food intake, anticonvulsant and anti-inflammatory effects, and protection of muscle tissue in different pathological conditions. In particular, ghrelin and GHS inhibit cardiomyocyte and endothelial cell apoptosis and improve cardiac left ventricular function during ischemia–reperfusion injury. Moreover, in a model of cisplatin-induced cachexia, GHS protect skeletal muscle from mitochondrial damage and improve lean mass recovery. Most of these effects are mediated by GHS ability to preserve intracellular Ca2+ homeostasis. In this review, we address the muscle-specific protective effects of GHS mediated by Ca2+ regulation, but also highlight recent findings of their therapeutic potential in pathological conditions characterized by skeletal or cardiac muscle impairment.
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9
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A P, P SR, M PR, K G R. Apoptosis in angiotensin II-stimulated hypertrophic cardiac cells -modulation by phenolics rich extract of Boerhavia diffusa L. Biomed Pharmacother 2018; 108:1097-1104. [PMID: 30372810 DOI: 10.1016/j.biopha.2018.09.114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/19/2018] [Accepted: 09/19/2018] [Indexed: 02/04/2023] Open
Abstract
Herein, we investigated the effects of B. diffusa (BDE), a well-known cardiotonic edible medicinal plant against apoptosis in Angiotensin II (Ang II)-stimulated hypertrophic cardiac cells (H9c2). The cells were analyzed for viability, markers of hypertrophy, apoptosis, and the expression of various proteins related to apoptosis. Ang II (100 nM for 48 h)-exposed H9c2 cells treated with BDE (75 μg/ml) showed a significant reduction in apoptosis (58.60%↓) compared to Ang II-alone treated cells. BDE treatment significantly reduced the up-regulation of Bax and cytosolic cytochrome-C caused by Ang II as well as reduced the degree of Ang II- induced down-regulation of Bcl-2. A reduction in caspase-3 activity (33.77%↓) and down-regulation of TNF-α was also observed in BDE treated cells stimulated with Ang II. Furthermore, the up-regulation of phospho-p38 MAPK was attenuated by BDE treatment. Bioactive components in the extract were identified as boeravinone B, quercetin, kaempferol, and caffeic acid as evident from high-performance liquid chromatography (HPLC). Overall, our study shows that B. diffusa is effective in attenuating apoptosis in cardiac cells, which is a major contributor to sudden cardiac death in addition to its nutraceutical properties.
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Affiliation(s)
- Prathapan A
- Biochemistry & Molecular Mechanism Laboratory, Agro-Processing and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India
| | - Salin Raj P
- Biochemistry & Molecular Mechanism Laboratory, Agro-Processing and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India
| | - Priya Rani M
- Biochemistry & Molecular Mechanism Laboratory, Agro-Processing and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India
| | - Raghu K G
- Biochemistry & Molecular Mechanism Laboratory, Agro-Processing and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India.
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10
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McDonald H, Peart J, Kurniawan N, Galloway G, Royce S, Samuel CS, Chen C. Hexarelin treatment preserves myocardial function and reduces cardiac fibrosis in a mouse model of acute myocardial infarction. Physiol Rep 2018; 6:e13699. [PMID: 29756411 PMCID: PMC5949285 DOI: 10.14814/phy2.13699] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 04/14/2018] [Indexed: 12/11/2022] Open
Abstract
Ischemic heart disease (IHD) is a leading cause of morbidity and mortality worldwide. Growth hormone secretagogues (GHS) have been shown to improve cardiac function in models of IHD. This study determined whether hexarelin (HEX), a synthetic GHS, preserves cardiac function and morphology in a mouse model of myocardial infarction (MI). MI was induced by ligation of the left descending coronary artery in C57BL/6J mice followed by vehicle (VEH; n = 10) or HEX (0.3 mg/kg/day; n = 11) administration for 21 days. MI-injured and sham mice (treated with VEH; n = 6 or HEX; n = 5) underwent magnetic resonance imaging for measurement of left ventricular (LV) function, mass and infarct size at 24 h and 14 days post-MI. MI-HEX mice displayed a significant improvement (P < 0.05) in LV function compared with MI-VEH mice after 14 days treatment. A significant decrease in LV mass, interstitial collagen and collagen concentration was demonstrated with chronic HEX treatment (for 21 days), accompanied by a decrease in TGF-β1 expression, myofibroblast differentiation and an increase in collagen-degrading MMP-13 expression levels. Furthermore, heart rate variability analysis demonstrated that HEX treatment shifted the balance of autonomic nervous activity toward a parasympathetic predominance and sympathetic downregulation. This was combined with a HEX-dependent decrease in troponin-I, IL-1β and TNF-α levels suggestive of amelioration of cardiomyocyte injury. These results demonstrate that GHS may preserve ventricular function, reduce inflammation and favorably remodel the process of fibrotic healing in a mouse model of MI and hold the potential for translational application to patients suffering from MI.
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Affiliation(s)
- Hayley McDonald
- School of Biomedical ScienceUniversity of QueenslandBrisbaneAustralia
| | - Jason Peart
- Menzies Health Institute of QueenslandGriffith UniversityGold CoastAustralia
| | - Nyoman Kurniawan
- Centre for Advanced ImagingUniversity of QueenslandBrisbaneAustralia
| | - Graham Galloway
- Centre for Advanced ImagingUniversity of QueenslandBrisbaneAustralia
| | - Simon Royce
- Cardiovascular Disease ProgramBiomedical Discovery Institute and Department of PharmacologyMonash UniversityVictoriaAustralia
- Central Clinical SchoolMonash UniversityVictoriaAustralia
| | - Chrishan S. Samuel
- Cardiovascular Disease ProgramBiomedical Discovery Institute and Department of PharmacologyMonash UniversityVictoriaAustralia
| | - Chen Chen
- School of Biomedical ScienceUniversity of QueenslandBrisbaneAustralia
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11
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Zhang X, Qu L, Chen L, Chen C. Improvement of cardiomyocyte function by in vivo hexarelin treatment in streptozotocin-induced diabetic rats. Physiol Rep 2018; 6:e13612. [PMID: 29446246 PMCID: PMC5812882 DOI: 10.14814/phy2.13612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/12/2018] [Accepted: 01/16/2018] [Indexed: 01/27/2023] Open
Abstract
Diabetic cardiomyopathy is characterized by diastolic and systolic cardiac dysfunction, yet no therapeutic drug to specifically treat it. Hexarelin has been demonstrated to improve heart function in various types of cardiomyopathy via its receptor GHS-R. This experiment aims to test the effect of hexarelin on cardiomyocytes under experimental diabetes. Streptozotocin (STZ, 65 mg/kg)-induced diabetic rat model was employed with vehicle injection group as control. Daily hexarelin (100 μg/kg) treatment was performed for 2 weeks after 4-week STZ-induced diabetes. Cardiomyocytes were isolated by enzyme treatment under O2 -saturated perfusion for single-cell shortening, [Ca2+ ]i transient, and electrophysiology recordings. GHS-R expression and apoptosis-related signaling proteins Bax, Bcl-2, caspase-3 and 9, were assessed by western blot. Experimental data demonstrated a reduced cell contraction and relaxation in parallel with depressed rise and fall of [Ca2+ ]i transients in diabetic cardiomyocytes. Hexarelin reversed the changes in both contraction and [Ca2+ ]i . Action potential duration and transient outward potassium current (Ito ) density were dramatically increased in diabetic cardiomyocytes and hexarelin treatment reverse such changes. Upregulated GHS receptor (GHS-R) expression was observed in both control and diabetic groups after hexarelin treatment, which also caused antiapoptotic changes of Bax, Bcl-2, caspase-3 and 9 expression. In STZ-induced diabetic rats, hexarelin is able to improve cardiomyocyte function through recovery of Ito K+ currents, intracellular Ca2+ homeostasis and antiapoptotic signaling pathways.
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Affiliation(s)
- Xinli Zhang
- School of Biomedical SciencesUniversity of QueenslandSt LuciaBrisbaneQueenslandAustralia
| | - Linbing Qu
- State Key Laboratories of Respiratory DiseasesGuangzhou Institutes of Biomedicine and HealthChinese Academy of SciencesGuangzhouChina
| | - Ling Chen
- State Key Laboratories of Respiratory DiseasesGuangzhou Institutes of Biomedicine and HealthChinese Academy of SciencesGuangzhouChina
| | - Chen Chen
- School of Biomedical SciencesUniversity of QueenslandSt LuciaBrisbaneQueenslandAustralia
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12
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Chu L, Li P, Song T, Han X, Zhang X, Song Q, Liu T, Zhang Y, Zhang J. Protective effects of tannic acid on pressure overload-induced cardiac hypertrophy and underlying mechanisms in rats. J Pharm Pharmacol 2017. [DOI: 10.1111/jphp.12763] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Abstract
Objectives
The aim of this study was to examine the cardioprotective effects and latent mechanism of tannic acid (TA) on cardiac hypertrophy.
Methods
Abdominal aortic banding (AAB) was used to induce pressure overload-induced cardiac hypertrophy in male Wistar rats, sham-operated rats served as controls. AAB rats were treated with TA (20 and 40 mg/kg) or captoril.
Key findings
Abdominal aortic banding rats that received TA showed ameliorated pathological changes in cardiac morphology and coefficients, decreased cardiac hypertrophy and apoptosis, a reduction in over expressions of angiotensin type 1 receptor (AT1R), angiotensin type 2 receptor (AT2R), phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and transforming growth factor-β (TGF-β) mRNA, and modified expression of matrix metal proteinase-9 (MMP-9) mRNA in AAB rat hearts. Furthermore, TA treatment contributed to a decrease in malondialdehyde (MDA) and endothelin-1 (ET-1) activities and content, while it caused an increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), nitric oxide (NO) and endothelial NO synthase (e-NOS). Furthermore, TA downregulated expression of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), bax, caspase-3 and upregulated expression of bcl-2.
Conclusions
Tannic acid displayed obvious suppression of AAB-induced cardiac hypertrophy in rats. The cardioprotective effects of TA may be attributed to multitargeted inhibition of oxidative stress, inflammation, fibrosis and apoptosis in addition to an increase in NO levels, decrease in ET-1 levels, and downregulation of angiotensin receptors and the phosphorylation of ERK1/2.
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Affiliation(s)
- Li Chu
- Hebei Medical University, Shijiazhuang, Hebei, China
- Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Pinya Li
- Hebei Medical University, Shijiazhuang, Hebei, China
| | - Tao Song
- Hebei Medical University, Shijiazhuang, Hebei, China
| | - Xue Han
- Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Xuan Zhang
- Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Qiongtao Song
- Hebei Medical University, Shijiazhuang, Hebei, China
| | - Tao Liu
- Hebei Medical University, Shijiazhuang, Hebei, China
| | - Yuanyuan Zhang
- Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
| | - Jianping Zhang
- Hebei University of Chinese Medicine, Shijiazhuang, Hebei, China
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13
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Abstract
Ghrelin is a small peptide released primarily from the stomach. It is a potent stimulator of growth hormone secretion from the pituitary gland and is well known for its regulation of metabolism and appetite. There is also a strong relationship between ghrelin and the cardiovascular system. Ghrelin receptors are present throughout the heart and vasculature and have been linked with molecular pathways, including, but not limited to, the regulation of intracellular calcium concentration, inhibition of proapoptotic cascades, and protection against oxidative damage. Ghrelin shows robust cardioprotective effects including enhancing endothelial and vascular function, preventing atherosclerosis, inhibiting sympathetic drive, and decreasing blood pressure. After myocardial infarction, exogenous administration of ghrelin preserves cardiac function, reduces the incidence of fatal arrhythmias, and attenuates apoptosis and ventricular remodeling, leading to improvements in heart failure. It ameliorates cachexia in end-stage congestive heart failure patients and has shown clinical benefit in pulmonary hypertension. Nonetheless, since ghrelin's discovery is relatively recent, there remains a substantial amount of research needed to fully understand its clinical significance in cardiovascular disease.
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From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation. Int J Mol Sci 2017; 18:ijms18020273. [PMID: 28134808 PMCID: PMC5343809 DOI: 10.3390/ijms18020273] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 01/19/2017] [Indexed: 12/20/2022] Open
Abstract
Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a) internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrally-mediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin’s central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry.
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15
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Huang J, Li Y, Zhang J, Liu Y, Lu Q. The Growth Hormone Secretagogue Hexarelin Protects Rat Cardiomyocytes From in vivo Ischemia/Reperfusion Injury Through Interleukin-1 Signaling Pathway. Int Heart J 2017; 58:257-263. [DOI: 10.1536/ihj.16-241] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Jiannan Huang
- Department of Cardiology, The Second Hospital of Shandong University
- Department of Cardiology, The Central Hospital of Zibo City
| | - Yi Li
- Obstetric Genetic Disease Laboratory, Maternal and Child Health Hospital of Zibo City
| | - Juan Zhang
- Department of Cardiology, The Central Hospital of Zibo City
| | - Yusheng Liu
- Department of Cardiology, The Second Hospital of Shandong University
| | - Qinghua Lu
- Department of Cardiology, The Second Hospital of Shandong University
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16
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Nakayama H, Nishida K, Otsu K. Macromolecular Degradation Systems and Cardiovascular Aging. Circ Res 2016; 118:1577-92. [DOI: 10.1161/circresaha.115.307495] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 02/29/2016] [Indexed: 11/16/2022]
Abstract
Aging-related cardiovascular diseases are a rapidly increasing problem worldwide. Cardiac aging demonstrates progressive decline of diastolic dysfunction of ventricle and increase in ventricular and arterial stiffness accompanied by increased fibrosis stimulated by angiotensin II and proinflammatory cytokines. Reactive oxygen species and multiple signaling pathways on cellular senescence play major roles in the process. Aging is also associated with an alteration in steady state of macromolecular dynamics including a dysfunction of protein synthesis and degradation. Currently, impaired macromolecular degradation is considered to be closely related to enhanced inflammation and be involved in the process and mechanism of cardiac aging. Herein, we review the role and mechanisms of the degradation system of intracellular macromolecules in the process and pathophysiology of cardiovascular aging.
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Affiliation(s)
- Hiroyuki Nakayama
- From the Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan (H.N.); and Cardiovascular Division, King’s College London British Heart Foundation Centre of Research Excellence, London, United Kingdom (K.N., K.O.)
| | - Kazuhiko Nishida
- From the Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan (H.N.); and Cardiovascular Division, King’s College London British Heart Foundation Centre of Research Excellence, London, United Kingdom (K.N., K.O.)
| | - Kinya Otsu
- From the Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan (H.N.); and Cardiovascular Division, King’s College London British Heart Foundation Centre of Research Excellence, London, United Kingdom (K.N., K.O.)
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17
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Mosa RMH, Zhang Z, Shao R, Deng C, Chen J, Chen C. Implications of ghrelin and hexarelin in diabetes and diabetes-associated heart diseases. Endocrine 2015; 49:307-23. [PMID: 25645463 DOI: 10.1007/s12020-015-0531-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/12/2015] [Indexed: 02/07/2023]
Abstract
Ghrelin and its synthetic analog hexarelin are specific ligands of growth hormone secretagogue (GHS) receptor. GHS have strong growth hormone-releasing effect and other neuroendocrine activities such as stimulatory effects on prolactin and adrenocorticotropic hormone secretion. Recently, several studies have reported other beneficial functions of GHS that are independent of GH. Ghrelin and hexarelin, for examples, have been shown to exert GH-independent cardiovascular activity. Hexarelin has been reported to regulate peroxisome proliferator-activated receptor gamma (PPAR-γ) in macrophages and adipocytes. PPAR-γ is an important regulator of adipogenesis, lipid metabolism, and insulin sensitization. Ghrelin also shows protective effects on beta cells against lipotoxicity through activation of phosphatidylinositol-3 kinase/protein kinase B, c-Jun N-terminal kinase (JNK) inhibition, and nuclear exclusion of forkhead box protein O1. Acylated ghrelin (AG) and unacylated ghrelin (UAG) administration reduces glucose levels and increases insulin-producing beta cell number, and insulin secretion in pancreatectomized rats and in newborn rats treated with streptozotocin, suggesting a possible role of GHS in pancreatic regeneration. Therefore, the discovery of GHS has opened many new perspectives in endocrine, metabolic, and cardiovascular research areas, suggesting the possible therapeutic application in diabetes and diabetic complications especially diabetic cardiomyopathy. Here, we review the physiological roles of ghrelin and hexarelin in the protection and regeneration of beta cells and their roles in the regulation of insulin release, glucose, and fat metabolism and present their potential therapeutic effects in the treatment of diabetes and diabetic-associated heart diseases.
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18
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Li B, Tian J, Sun Y, Xu TR, Chi RF, Zhang XL, Hu XL, Zhang YA, Qin FZ, Zhang WF. Activation of NADPH oxidase mediates increased endoplasmic reticulum stress and left ventricular remodeling after myocardial infarction in rabbits. Biochim Biophys Acta Mol Basis Dis 2015; 1852:805-15. [DOI: 10.1016/j.bbadis.2015.01.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/12/2015] [Accepted: 01/16/2015] [Indexed: 12/21/2022]
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The cardiovascular action of hexarelin. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2014; 11:253-8. [PMID: 25278975 PMCID: PMC4178518 DOI: 10.11909/j.issn.1671-5411.2014.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 05/25/2014] [Accepted: 07/10/2014] [Indexed: 11/21/2022]
Abstract
Hexarelin, a synthetic growth hormone-releasing peptide, can bind to and activate the growth hormone secretagogue receptor (GHSR) in the brain similar to its natural analog ghrelin. However, the peripheral distribution of GHSR in the heart and blood vessels suggests that hexarelin might have direct cardiovascular actions beyond growth hormone release and neuroendocrine effects. Furthermore, the non-GHSR CD36 had been demonstrated to be a specific cardiac receptor for hexarelin and to mediate its cardioprotective effects. When compared with ghrelin, hexarelin is chemically more stable and functionally more potent. Therefore, it may be a promising therapeutic agent for some cardiovascular conditions. In this concise review, we discuss the current evidence for the cardiovascular action of hexarelin.
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Huang CY, Kuo WW, Kuo CH, Tsai FJ, Liu PY, Hsieh DJY. Protective effect of Danggui (Radix Angelicae Sinensis) on angiotensin II-induced apoptosis in H9c2 cardiomyoblast cells. Altern Ther Health Med 2014; 14:358. [PMID: 25256260 PMCID: PMC4182826 DOI: 10.1186/1472-6882-14-358] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/19/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND Danggui (Radix Angelicae Sinensis) is an herb often used in Traditional Chinese medicine. It is used to promote blood flow and has been used in the treatment of myocardial ischemia-reperfusion injury in animal models. Angiotensin II (Ang II) has been shown to play important roles in mediating cardiovascular diseases, and may cause cardiac hypertrophy and apoptosis. This study aimed to investigate whether Danggui has protective effects on Ang II-induced apoptosis in H9c2 cardiomyoblast cells and study the mechanisms involved. METHODS We evaluated the effect of Danggui on Ang II-induced apoptosis in an in vitro model. H9c2 cardiomyoblast cells were cultured in serum-free medium for 4 hr, then treated with Danggui (50, 100 μg/ml) 1 hr pre- or post-Ang II treatment. After a further 23 hr of culture, cells were harvested for analyses with assays for apoptosis markers and cell signaling pathways. RESULTS Our results showed that Ang II induced upregulation of pro-apoptotic Bad, instability of the mitochondria membrane potential, cytochrome c release, caspase-9 and caspase-3 activation and cardiomyocyte apoptosis. Pre- or post-treatment with Danggui reversed all of the above Ang II-induced apoptotic effects in H9c2 cells. Furthermore, the JNK (SP600125) inhibitor completely blocked Danggui inhibition of caspase-3 activation in Ang II-treated H9c2 cells. CONCLUSIONS Our results showed that Danggui either pre-treatment or post-treatment highly attenuated the Ang II-induced apoptosis in cardiomyoblast cells. The findings demonstrated that the anti-apoptosis effect of Danggui is mediated by JNK and PI3k inhibitors.
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21
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Park SJ, Chung YH, Lee JH, Dang DK, Nam Y, Jeong JH, Kim YS, Nabeshima T, Shin EJ, Kim HC. Growth Hormone-Releaser Diet Attenuates Cognitive Dysfunction in Klotho Mutant Mice via Insulin-Like Growth Factor-1 Receptor Activation in a Genetic Aging Model. Endocrinol Metab (Seoul) 2014; 29:336-48. [PMID: 25309793 PMCID: PMC4192803 DOI: 10.3803/enm.2014.29.3.336] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/26/2013] [Accepted: 12/13/2013] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND It has been recognized that a defect in klotho gene expression accelerates the degeneration of multiple age-sensitive traits. Accumulating evidence indicates that aging is associated with declines in cognitive function and the activity of growth hormone (GH)/insulin-like growth factor-1 (IGF-1). METHODS In this study, we examined whether a GH-releaser diet could be effective in protecting against cognitive impairment in klotho mutant mice. RESULTS The GH-releaser diet significantly induced the expression of IGF-1 and IGF-1 receptors in the hippocampus of klotho mutant mice. Klotho mutant mice showed significant memory impairments as compared with wild-type mice. In addition, the klotho mutation significantly decreased the expression of cell survival/antiapoptotic factors, including phospho-Akt (p-Akt)/phospho-glycogen synthase kinase3β (p-GSK3β), phospho-extracellular signal-related kinase (p-ERK), and Bcl-2, but significantly increased those of cell death/proapoptotic factors, such as phospho-c-jun N-terminal kinase (p-JNK), Bax, and cleaved caspase-3 in the hippocampus. Treatment with GH-releaser diet significantly attenuated both decreases in the expression of cell survival/antiapoptotic factors and increases in the expression of cell death/proapoptotic factors in the hippocampus of klotho mutant mice. In addition, klotho mutation-induced oxidative stress was significantly attenuated by the GH-releaser diet. Consequently, a GH-releaser diet significantly improved memory function in the klotho mutant mice. GH-releaser diet-mediated actions were significantly reversed by JB-1, an IGF-1 receptor antagonist. CONCLUSION The results suggest that a GH-releaser diet attenuates oxidative stress, proapoptotic changes and consequent dysfunction in klotho mutant mice by promoting IGF-1 expression and IGF-1 receptor activation.
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Affiliation(s)
- Seok Joo Park
- Neuropsychopharmacology and Toxicology Program, Kangwon National University College of Pharmacy, Chunchon, Korea
- Ilsong Institute of Life Science, Hallym University, Anyang, Korea
| | - Yoon Hee Chung
- Department of Anatomy, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jeong Hyun Lee
- Neuropsychopharmacology and Toxicology Program, Kangwon National University College of Pharmacy, Chunchon, Korea
| | - Duy-Khanh Dang
- Neuropsychopharmacology and Toxicology Program, Kangwon National University College of Pharmacy, Chunchon, Korea
| | - Yunsung Nam
- Neuropsychopharmacology and Toxicology Program, Kangwon National University College of Pharmacy, Chunchon, Korea
- Department of Pharmacology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Yong Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Korea
| | - Toshitaka Nabeshima
- Department of Regional Pharmaceutical Care and Science, Meijo University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, Kangwon National University College of Pharmacy, Chunchon, Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, Kangwon National University College of Pharmacy, Chunchon, Korea
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22
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Liantonio A, Gramegna G, Carbonara G, Sblendorio VT, Pierno S, Fraysse B, Giannuzzi V, Rizzi L, Torsello A, Camerino DC. Growth hormone secretagogues exert differential effects on skeletal muscle calcium homeostasis in male rats depending on the peptidyl/nonpeptidyl structure. Endocrinology 2013; 154:3764-75. [PMID: 23836033 DOI: 10.1210/en.2013-1334] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The orexigenic and anabolic effects induced by ghrelin and the synthetic GH secretagogues (GHSs) are thought to positively contribute to therapeutic approaches and the adjunct treatment of a number of diseases associated with muscle wasting such as cachexia and sarcopenia. However, many questions about the potential utility and safety of GHSs in both therapy and skeletal muscle function remain unanswered. By using fura-2 cytofluorimetric technique, we determined the acute effects of ghrelin, as well as of peptidyl and nonpeptidyl synthetic GHSs on calcium homeostasis, a critical biomarker of muscle function, in isolated tendon-to-tendon male rat skeletal muscle fibers. The synthetic nonpeptidyl GHSs, but not peptidyl ghrelin and hexarelin, were able to significantly increase resting cytosolic calcium [Ca²⁺]i. The nonpeptidyl GHS-induced [Ca²⁺]i increase was independent of GHS-receptor 1a but was antagonized by both thapsigargin/caffeine and cyclosporine A, indicating the involvement of the sarcoplasmic reticulum and mitochondria. Evaluation of the effects of a pseudopeptidyl GHS and a nonpeptidyl antagonist of the GHS-receptor 1a together with a drug-modeling study suggest the conclusion that the lipophilic nonpeptidyl structure of the tested compounds is the key chemical feature crucial for the GHS-induced calcium alterations in the skeletal muscle. Thus, synthetic GHSs can have different effects on skeletal muscle fibers depending on their molecular structures. The calcium homeostasis dysregulation specifically induced by the nonpeptidyl GHSs used in this study could potentially counteract the beneficial effects associated with these drugs in the treatment of muscle wasting of cachexia- or other age-related disorders.
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MESH Headings
- Animals
- Appetite Stimulants/adverse effects
- Appetite Stimulants/pharmacology
- Calcium Signaling/drug effects
- Cell Line
- Cell Membrane Permeability/drug effects
- Cell Survival/drug effects
- Cytosol/drug effects
- Cytosol/metabolism
- Ghrelin/analogs & derivatives
- Ghrelin/metabolism
- Growth Hormone/metabolism
- Male
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Oligopeptides/adverse effects
- Oligopeptides/pharmacology
- Piperidines/adverse effects
- Piperidines/pharmacology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/metabolism
- Rats
- Rats, Wistar
- Receptors, Ghrelin/agonists
- Receptors, Ghrelin/antagonists & inhibitors
- Receptors, Ghrelin/metabolism
- Sarcolemma/drug effects
- Sarcolemma/metabolism
- Sarcoplasmic Reticulum/drug effects
- Sarcoplasmic Reticulum/metabolism
- Spiro Compounds/adverse effects
- Spiro Compounds/pharmacology
- Structure-Activity Relationship
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Affiliation(s)
- Antonella Liantonio
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Via Orabona, 4, Campus, I-70125 Bari, Italy.
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Cao J, Ding R, Wang Y, Chen D, Guo D, Liang C, Feng Z, Che Z. Toxic effect of cooking oil fumes in primary fetal pulmonary type II-like epithelial cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2013; 36:320-331. [PMID: 23708313 DOI: 10.1016/j.etap.2013.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 04/16/2013] [Accepted: 04/24/2013] [Indexed: 06/02/2023]
Abstract
Epidemiological studies indicated that there is an increased risk of respiratory tract cancer among cooks and bakers. The cooking oil fumes are believed to conduct this risk, and many studies have focused on evaluating the mutagenicity and finding the mutagenic components in oil fumes. COFs contains two major classes of compounds. One class consists of polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene, benzo[b]fluoranthene, fluoranthene, and benzo[g,h,i]perylene. BaP is a known immunosuppressant. It can also alter cell cycle progression, induce inflammation, and impair DNA repair and apoptotic processes leading to aberrant cellular functioning. This study investigates the effect of toxicity of cooking oil fumes (COFs) in primary ICR mice' fetal lung type II-like epithelium cells (AEC II). The cells were cultured in different concentrations (0, 12.5, 25, 50, 100, and 200μg/ml) of COFs for different time periods. The results showed that cell viability decreased in a dose- and time- dependent manner, which is accompanied by increased malondialdehyde (MDA) level and decreased superoxide dismutase (SOD) and glutathione (GSH) activities. Moreover, comet assay suggested DNA damage, as well as increased production of DNA adducts induced by PAHs. The present study also shows that COFs may disturb cell cycles even at a very low dose. In summary, the present study indicates that COFs may lead to toxicity in AEC II cells.
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Affiliation(s)
- Jiyu Cao
- School of Public Health, Anhui Medical University, Hefei, China.
| | - Rui Ding
- School of Public Health, Anhui Medical University, Hefei, China
| | - Yong Wang
- School of Public Health, Anhui Medical University, Hefei, China
| | - Daojun Chen
- School of Public Health, Anhui Medical University, Hefei, China
| | - Dongmei Guo
- School of Public Health, Anhui Medical University, Hefei, China
| | - Chunmei Liang
- School of Public Health, Anhui Medical University, Hefei, China
| | - Zhewei Feng
- School of Public Health, Anhui Medical University, Hefei, China
| | - Zhen Che
- School of Public Health, Anhui Medical University, Hefei, China
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Ghrelin protects H9c2 cardiomyocytes from angiotensin II-induced apoptosis through the endoplasmic reticulum stress pathway. J Cardiovasc Pharmacol 2012; 59:465-71. [PMID: 22269847 DOI: 10.1097/fjc.0b013e31824a7b60] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ghrelin, a gastric hormone, exerts cardioprotective function by increasing myocardial contractility and vasodilation. Previous studies have reported that angiotensin II (Ang II) production increased in heart failure, which can induce cardiomyocyte apoptosis. In this study, we investigated the effect of ghrelin on Ang II-induced H9c2 cardiomyocyte apoptosis. The results showed that Ang II inhibited H9c2 cell viability, which was blocked by ghrelin. By annexin V-propidium iodide dual staining and 2'-deoxyuridine 5'-triphosphate nick end-labeling analysis, we found that Ang II induced H9c2 cell apoptosis, whereas coincubation of ghrelin with Ang II significantly reduced H9c2 cell apoptosis induced by Ang II. Simultaneously, the results revealed that ghrelin regulated the Ang II-induced imbalance of Bax and Bcl-2 expression and reduced Ang II-induced caspase-3 expression. Moreover, mRNA expressions of endoplasmic reticulum stress-related molecules GRP78, caspase-12, and C/EBP homologous protein were significantly upregulated by Ang II. However, their expressions were significantly inhibited by ghrelin. In addition, we found that ghrelin markedly inhibited Ang II-induced Ang II type 1 receptor expression. These data suggest that ghrelin may play an antagonistic role in Ang II-induced cardiomyocyte apoptosis via decreasing Ang II type 1 receptor expression and inhibiting the activation of endoplasmic reticulum stress pathway.
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25
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Stengel A, Taché Y. Ghrelin - a pleiotropic hormone secreted from endocrine x/a-like cells of the stomach. Front Neurosci 2012; 6:24. [PMID: 22355282 PMCID: PMC3280431 DOI: 10.3389/fnins.2012.00024] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 01/29/2012] [Indexed: 12/13/2022] Open
Abstract
The gastric X/A-like endocrine cell receives growing attention due to its peptide products with ghrelin being the best characterized. This peptide hormone was identified a decade ago as a stimulator of food intake and to date remains the only known peripherally produced and centrally acting orexigenic hormone. In addition, subsequent studies identified numerous other functions of this peptide including the stimulation of gastrointestinal motility, the maintenance of energy homeostasis and an impact on reproduction. Moreover, ghrelin is also involved in the response to stress and assumed to play a role in coping functions and exert a modulatory action on immune pathways. Our knowledge on the regulation of ghrelin has markedly advanced during the past years by the identification of the ghrelin acylating enzyme, ghrelin-O-acyltransferase, and by the description of changes in expression, activation, and release under different metabolic as well as physically and psychically challenging conditions. However, our insight on regulatory processes of ghrelin at the cellular and subcellular levels is still very limited and warrants further investigation.
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Affiliation(s)
- Andreas Stengel
- Division Psychosomatic Medicine and Psychotherapy, Department of Medicine, Charité - Universitätsmedizin Berlin Berlin, Germany
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26
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Endoplasmic reticulum stress caused by left ventricular hypertrophy in rats: effects of telmisartan. Am J Med Sci 2011; 342:318-23. [PMID: 21642821 DOI: 10.1097/maj.0b013e3182112baf] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Studies have revealed that excessive endoplasmic reticulum (ER) stress leads to apoptosis. Although cardiomyocytes apoptosis contributes to the transition from left ventricular hypertrophy (LVH) to heart failure, it is unknown whether ER stress participates in the pathologic process. The authors first induced coarctation of the abdominal aorta in rats to induce LVH and then investigated the effect of telmisartan on the resulting ER stress. METHODS Male Sprague-Dawley rats were randomly divided into 3 groups: sham operation, abdominal aortic coarctation (AAC) and AAC + telmisartan. Telmisartan (5 mg · kg · d) or vehicle was infused into the stomach 1 week after the operation. ER stress signaling pathway molecules and apoptosis were studied in pressure-overloaded hearts 9 weeks after AAC. RESULTS Telmisartan significantly reduced LVH and interstitial fibrosis and improved left ventricular function compared with AAC alone. Cardiac markers of ER stress such as GRP78, C/EBP homologous protein, caspase-12 and phospho c-Jun NH2-terminal kinase were significantly increased in rats with AAC, and telmisartan significantly blunted these changes. Rats that received both telmisartan and AAC had less apoptosis due to ER stress. CONCLUSIONS Increased ER stress might be responsible for enhanced cardiomyocyte apoptosis after aortic coarctation. Telmisartan may reduce ER stress and thereby attenuate both apoptosis and cardiac hypertrophy.
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Zhang G, Yin X, Qi Y, Pendyala L, Chen J, Hou D, Tang C. Ghrelin and cardiovascular diseases. Curr Cardiol Rev 2011; 6:62-70. [PMID: 21286280 PMCID: PMC2845796 DOI: 10.2174/157340310790231662] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/27/2009] [Accepted: 04/03/2009] [Indexed: 01/19/2023] Open
Abstract
Ghrelin, a newly discovered bioactive peptide, is a natural endogenous ligand of the growth hormone (GH) secretagogue receptor and initially identified as a strong stimulant for the release of GH. Subsequent research has shown that ghrelin and its various receptors are ubiquitous in many other organs and tissues. Moreover, they participate in the regulation of appetite, energy, bodyweight, metabolism of glucose and fat, as well as modulation of gastrointestinal, cardiovascular, pulmonary, immune functions and cell proliferation/apoptosis. Increasing evidence has demonstrated that ghrelin has a close relationship with cardiovascular system. Ghrelin and its receptors are widely distributed in cardiovascular tissues, and there is no doubt that the effects of ghrelin in the cardiovascular system are mediated not only via its growth-hormone-releasing effect but also by its direct effects on the heart. Exogenous administration of ghrelin can dilate peripheral blood vessels, constrict coronary artery, improve endothelial function, as well as inhibit myocardial cell apoptosis. So, ghrelin may have cardiovascular protective effect, including lowering of blood pressure, regulation of atherosclerosis, and protection from ischemia/reperfusion injury as well as improving the prognosis of myocardial infarction and heart failure. Some of these new functions of ghrelin may provide new potential therapeutic opportunities for ghrelin in cardiovascular medicine. In this paper, we will review the existing evidence for cardiovascular effects of ghrelin, including the cardiovascular function, the variations in ghrelin plasma levels in pathophysiologicalogical conditions, the possible protective mechanisms of ghrelin, as well as its future potential therapeutic roles.
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Affiliation(s)
- Gaigai Zhang
- Cardiology Department, the First Affiliated Hospital of Harbin Medical University, Harbin,P. R. China 150081
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Pang J, Xu X, Getman MR, Shi X, Belmonte SL, Michaloski H, Mohan A, Blaxall BC, Berk BC. G protein coupled receptor kinase 2 interacting protein 1 (GIT1) is a novel regulator of mitochondrial biogenesis in heart. J Mol Cell Cardiol 2011; 51:769-76. [PMID: 21756914 DOI: 10.1016/j.yjmcc.2011.06.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 06/15/2011] [Accepted: 06/26/2011] [Indexed: 12/22/2022]
Abstract
G-protein-coupled receptor (GPCR)-kinase interacting protein-1 (GIT1) is a multi-function scaffold protein. However, little is known about its physiological role in the heart. Here we sought to identify the cardiac function of GIT1. Global GIT1 knockout (KO) mice were generated and exhibited significant cardiac hypertrophy that progressed to heart failure. Electron microscopy revealed that the hearts of GIT1 KO mice demonstrated significant morphological abnormities in mitochondria, including decreased mitochondrial volume density, cristae density and increased vacuoles. Moreover, mitochondrial biogenesis-related gene peroxisome proliferator-activated receptor γ (PPARγ) co-activator-1α (PGC-1α), PGC-1β, mitochondrial transcription factor A (Tfam) expression, and total mitochondrial DNA were remarkably decreased in hearts of GIT1 KO mice. These animals also had impaired mitochondrial function, as evidenced by reduced ATP production and dissipated mitochondrial membrane potential (Ψ(m)) in adult cardiomyocytes. Concordant with these mitochondrial observations, GIT1 KO mice showed enhanced cardiomyocyte apoptosis and cardiac dysfunction. In conclusion, our findings identify GIT1 as a new regulator of mitochondrial biogenesis and function, which is necessary for postnatal cardiac maturation.
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Affiliation(s)
- Jinjiang Pang
- Aab Cardiovascular Research Institute, Rochester, NY 14642, USA.
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Isgaard J, Granata R. Ghrelin in cardiovascular disease and atherogenesis. Mol Cell Endocrinol 2011; 340:59-64. [PMID: 21458527 DOI: 10.1016/j.mce.2011.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 03/01/2011] [Accepted: 03/01/2011] [Indexed: 11/16/2022]
Abstract
Although initially associated with regulation of appetite, the cardiovascular system has also been recognized as a potentially important target for ghrelin. Moreover, a limited number of clinical studies suggest a role for ghrelin in the treatment of congestive heart failure. So far reported cardiovascular effects of growth hormone secretagogues and/or ghrelin include lowering of peripheral resistance, either direct at the vascular level and/or by modulating sympathetic nervous activity. Other observed effects indicate possible improvement of contractility and cardioprotective effects both in vivo and in vitro.Taken together, these results offer an interesting perspective on the future where further studies aiming at evaluating a role of GHS and ghrelin in the treatment of cardiovascular disease are warranted.
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Affiliation(s)
- Jörgen Isgaard
- Department of Internal Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gröna Stråket 8, Gothenburg, Sweden.
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Ghrelin protects spinal cord motoneurons against chronic glutamate-induced excitotoxicity via ERK1/2 and phosphatidylinositol-3-kinase/Akt/glycogen synthase kinase-3β pathways. Exp Neurol 2011; 230:114-22. [PMID: 21530509 DOI: 10.1016/j.expneurol.2011.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 03/29/2011] [Accepted: 04/07/2011] [Indexed: 12/13/2022]
Abstract
Excitotoxic degeneration of spinal cord motoneurons has been proposed as a pathogenic mechanism in amyotrophic lateral sclerosis (ALS). Recently, we have reported that ghrelin, an endogenous ligand for growth hormone secretagogue receptor (GHS-R) 1a, functions as a neuroprotective factor in various animal models of neurodegenerative diseases. In this study, the potential neuroprotective effects of ghrelin against chronic glutamate-induced cell death were studied by exposing organotypic spinal cord cultures (OSCC) to threohydroxyaspartate (THA), as a model of excitotoxic motoneuron degeneration. Ghrelin receptor was expressed on spinal cord motoneurons. Exposure of OSCC to THA for 3 weeks resulted in a significant loss of motoneurons. However, THA-induced loss of motoneurons was significantly reduced by treatment of ghrelin. Exposure of OSCC to the receptor-specific antagonist D-Lys-3-GHRP-6 abolished the protective effect of ghrelin against THA. Treatment of spinal cord cultures with ghrelin caused rapid phosphorylation of extracellular signal-regulated kinase 1/2, Akt, and glycogen synthase kinase-3β (GSK-3β). The effect of ghrelin on motoneuron survival was blocked by the MEK inhibitor PD98059 and the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002. Taken together, these findings indicate that ghrelin has neuroprotective effects against chronic glutamate toxicity by activating the MAPK and PI3K/Akt signaling pathways and suggest that administration of ghrelin may have the potential therapeutic value for the prevention of motoneuron degeneration in human ALS. Our data also suggest that PI3K/Akt-mediated inactivation of GSK-3β in motoneurons contributes to the protective effect of ghrelin.
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Repaci A, Gambineri A, Pasquali R. The role of low-grade inflammation in the polycystic ovary syndrome. Mol Cell Endocrinol 2011; 335:30-41. [PMID: 20708064 DOI: 10.1016/j.mce.2010.08.002] [Citation(s) in RCA: 186] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 07/27/2010] [Accepted: 08/05/2010] [Indexed: 11/29/2022]
Abstract
PCOS is not only the most frequent cause of oligomenorrhea in young women, but also a metabolic disorder characterized by insulin resistance, glucose intolerance, dyslipidemia, and obesity, especially the visceral phenotype. PCOS represents a broad spectrum of endocrine and metabolic alterations which change with age and with increasing adiposity. In fact, during adolescence and youth the predominant clinical manifestations of PCOS are menstrual abnormalities, hirsutism and acne, whereas in peri-menopausal and post-menopausal periods metabolic disorders and an increased risk for cardiovascular diseases prevail. The pathogenetic links between PCOS and metabolic or cardiovascular complications are still debated. However, recent evidence has been focused on a condition of low-grade chronic inflammation as a potential cause of the long-term consequence of the syndrome. In this review we describe the state of low-grade inflammation observed in PCOS. In addition, we hypothesize the potential mechanisms responsible for the generation of this inflammatory state and the role played by low-grade inflammation in linking hyperandrogenism and insulin resistance with the metabolic and cardiovascular long-term complications of the syndrome.
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Affiliation(s)
- Andrea Repaci
- Division of Endocrinology, Department of Clinical Medicine, S. Orsola-Malpighi Hospital, University Alma Mater Studiorum of Bologna, Via Massarenti 9, 40138 Bologna, Italy
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Yu Y, Satoh H, Vila A, Wu SM, Marshak DW. Effects of histamine on light responses of amacrine cells in tiger salamander retina. Neurochem Res 2010; 36:645-54. [PMID: 20878231 DOI: 10.1007/s11064-010-0278-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2010] [Indexed: 11/24/2022]
Abstract
Using immunofluorescence, we showed that histamine receptor 1 is expressed by horizontal cell axons and a subset of amacrine cells in the tiger salamander retina. The effects of histamine on light responses of amacrine cells were studied in slice preparations. Histamine modulated the light responses of many salamander amacrine cells, depending upon the morphological type. The most pronounced effects of histamine were decreases in the light responses of broadly stratified amacrine cells, particularly those having medium-sized dendritic field diameters. To determine whether the effects of histamine were direct, Co(++) was substituted for Ca(++) in the extracellular medium to block synaptic transmission. Histamine still affected broadly stratified amacrine cells, but not narrowly stratified amacrine cells under these conditions. Taken together, these findings suggest that inhibitory interactions between strata of the IPL and within the classical receptive fields of the ganglion cells would be particularly sensitive to histamine released from retinopetal axons.
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Affiliation(s)
- Yongchun Yu
- Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, Houston, TX 77225, USA
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Pang J, Xu Q, Xu X, Yin H, Xu R, Guo S, Hao W, Wang L, Chen C, Cao JM. Hexarelin suppresses high lipid diet and vitamin D3-induced atherosclerosis in the rat. Peptides 2010; 31:630-8. [PMID: 19931584 DOI: 10.1016/j.peptides.2009.11.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 11/10/2009] [Accepted: 11/10/2009] [Indexed: 10/20/2022]
Abstract
Growth hormone-releasing peptides (GHRP) and ghrelin are synthetic and natural ligands of growth hormone secretagogue receptor (GHSR) respectively and are shown to exert protective actions on cardiac dysfunction. Because ghrelin has been reported to inhibit proinflammatory responses in human endothelium and GHSR has been identified in blood vessels, we hypothesized that GHRP could alleviate the development of atherosclerosis (As). Atherosclearosis was induced by a short period (4 days) of vitamin D(3) and chronic (three months) intragastric feeding of high fat emulsion (containing 0.5% propylthiouracil) in adult SD rats. Some As rats received chronic hexarelin (a variant of GHRP) injection (SC BID, 30 days) and normal rats received placebo as control. Significant atherosclerosis developed in animals fed with the emulsion. Serum total cholesterol and LDL-c increased, and HDL-c and aortic nitric oxide (NO) decreased significantly in As group. Hexarelin suppressed the formation of atherosclerotic plaques and neointima, partially reversed serum HDL-c/LDL-c ratio and increased the levels of serum NO and aortic mRNAs of eNOS, GHSR and CD36 in As rats. Hexarelin also decreased [(3)H]-TdR incorporation in cultured vascular smooth muscle cell (VSMC) and calcium sedimentation in aortic wall. Furthermore, foam cell formation induced by ox-LDL was decreased by hexarelin. In conclusion, hexarelin suppresses high lipid diet and vitamin D3-induced atherosclerosis in rats, possibly through upregulating HDL-c/LDL-c ratio, vascular NO production and downregulating the VSMC proliferation, aortic calcium sedimentation and foam cell formation. These novel anti-atherosclerotic actions of hexarelin suggest that the peptide might have a clinical potential in treating atherosclerosis.
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Affiliation(s)
- Jinjiang Pang
- Department of Physiology, School of Basic Medicine, Peking Union Medical College, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, 5 Dong Dan San Tiao, Beijing 100005, China
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Sun Q, Zang WJ, Chen C. Growth hormone secretagogues reduce transient outward K+ current via phospholipase C/protein kinase C signaling pathway in rat ventricular myocytes. Endocrinology 2010; 151:1228-35. [PMID: 20056829 DOI: 10.1210/en.2009-0877] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Endogenous ghrelin and its synthetic counterpart hexarelin are peptide GH secretagogues (GHS) that exert a positive ionotropic effect in the cardiovascular system. The mechanism by which GHS modulate cardiac electrophysiology properties to alter myocyte contraction is poorly understood. In the present study, we examined whether GHS regulates the transient outward potassium current (I(to)) as well as the putative intracellular signaling cascade responsible for such regulation. GHS and experimental agents were applied locally onto freshly isolated adult Sprague-Dawley rat ventricular myocytes and action potential morphology and I(to) was recorded using nystatin-perforated whole-cell patch-clamp recording technique. Under current clamp, ghrelin and hexarelin (10 nm) significantly prolonged action potential duration. Under voltage clamp, hexarelin and ghrelin inhibited I(to) in a concentration-dependent manner. This inhibition was abolished in the presence of the GHS receptor (GHS-R) antagonist [D-Lys(3)]GH-releasing peptide-6 (10 microm) and GHS-R1a-specific antagonist BIM28163 (1 microm). GHS-induced I(to) inhibition was totally reversed by the phospholipase C inhibitor U73122 (5 microm) and protein kinase C inhibitors GO6983 (1 microm) and calphostin C (0.1 microm) but not by the cAMP antagonist Rp-cAMP (100 microm) or the PKA inhibitor H89 (1 microm). We conclude that hexarelin and ghrelin activate phospholipase C and protein kinase C signaling cascade through the stimulation of the GHS-R, resulting in a decrease in the I(to) current and subsequent prolongation of action potential duration.
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Affiliation(s)
- Qiang Sun
- Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China
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Xu J, Lü XW, Huang Y, Zhu PL, Li J. Synergism of simvastatin with losartan prevents angiotensin II-induced cardiomyocyte apoptosis in vitro. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.61.04.0013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Objectives
Increasing evidence suggests that cardiomyocyte apoptosis has an important role in the transition from compensatory cardiac remodelling to heart failure. The synergistic effect of statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) and angiotensin II (Ang II) type 1 receptor antagonists reduces the incidence of cardiovascular events. However, the anti-apoptotic potential of the synergism between losartan and simvastatin in heart failure remains unexplored. Here, we demonstrate that Ang II-induced apoptosis is prevented by losartan and simvastatin in neonatal cardiomyocytes.
Methods
The in-vitro cardiomyocyte apoptosis model was established by co-culturing neonate rat cardiomyocytes with Ang II. Cell viability was analysed by the MTT assay. Cell apoptosis was evaluated using fluorescence microscopy and flow cytometry. Apoptosis-related proteins Bax and Bcl-2 expressions were measured by flow cytometry detection.
Key findings
Incubation with 10−7 m Ang II for 48 h increased cardiomyocyte apoptosis and decreased cell viability. Losartan (10−5 m) and simvastatin (10−5 m), either alone or in combination, significantly decreased Ang II-induced cardiomyocyte apoptosis and increased cell viability. The q values calculated by the probability sum test were 1.31 for cardiomyocyte apoptosis and 1.21 for cell viability. Ang II induced a significant increase in Bax protein expression, whereas Bcl-2 protein expression was decreased. Losartan alone or in combination with simvastatin blocked the increased Bax expression and increased Bcl-2 expression. However, simvastatin had no such effect.
Conclusions
Our data provide the first evidence that synergism of simvastatin with losartan prevents angiotensin II-induced cardiomyocyte apoptosis in vitro. Synergism between simvastatin and losartan may provide a new therapeutic approach to the prevention of cardiac remodelling.
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Affiliation(s)
- Jian Xu
- School of Pharmacy, Anhui Medical University, Hefei, China
- Department of Cardiology, Anhui Provincial Hospital, Hefei, China
| | - Xiong-wen Lü
- School of Pharmacy, Anhui Medical University, Hefei, China
| | - Yan Huang
- School of Pharmacy, Anhui Medical University, Hefei, China
| | - Peng-li Zhu
- School of Pharmacy, Anhui Medical University, Hefei, China
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei, China
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Lei XY, Yao SQ, Zu XY, Huang ZX, Liu LJ, Zhong M, Zhu BY, Tang SS, Liao DF. Apoptosis induced by diallyl disulfide in human breast cancer cell line MCF-7. Acta Pharmacol Sin 2008; 29:1233-9. [PMID: 18817629 DOI: 10.1111/j.1745-7254.2008.00851.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
AIM To investigate the effect of diallyl disulfide (DADS), a component of garlic, on apoptosis in human mammary cancer cell line (MCF-7) and its mechanisms. METHODS Cytotoxicity was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assays. Morphology of apoptotic cells was detected by acridine orange and ethidium bromide staining. Apoptotic cells stained with propidium iodide were examined using flow cytometry. Protein levels were detected by Western blot analysis. RESULTS DADS inhibited the proliferation of MCF-7 cells and induced the apoptotic ratio to increase rapidly. Cleavage of the caspase-3 and caspase-3 substrate poly(ADP-ribose) polymerase was observed in MCF-7 cells after 24 h of treatment with DADS. When the MCF-7 cells were treated with 200 micromol x L DADS, the stress-activated protein kinase extracellular signal-regulated kinase (ERK), a mitogen-activated protein kinase, was inhibited after 6 h; c-Jun N-terminal kinase (JNK), that is stress-activated protein kinase (SAPK), and p38 mitogen-activated protein kinase were activated after 6 h. CONCLUSION These results suggest that DADS both inhibits the proliferation of MCF-7 cells and induces apoptosis of MCF-7 cells. The mechanisms may include the inhibition of ERK and the activation of the SAPK/JNK and p38 pathways.
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Affiliation(s)
- Xiao-yong Lei
- Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, China.
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Xu X, Jhun BS, Ha CH, Jin ZG. Molecular mechanisms of ghrelin-mediated endothelial nitric oxide synthase activation. Endocrinology 2008; 149:4183-92. [PMID: 18450953 PMCID: PMC2488251 DOI: 10.1210/en.2008-0255] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Metabolic syndrome accelerates the atherosclerotic process, and the earliest event of which is endothelial dysfunction. Ghrelin, a newly discovered gastric peptide, improves endothelial function and inhibits proatherogenic changes. In particular, low ghrelin concentration has been associated with several features of metabolic syndrome, including obesity, insulin resistance, and high blood pressure. However, the molecular mechanisms underlying ghrelin vascular actions remain largely unclear. Here, we showed that ghrelin activated endothelial nitric oxide (NO) synthase (eNOS) in cultured endothelial cells (ECs) and in intact vessels. Specifically, ghrelin rapidly induced phosphorylation of eNOS on an activation site and production of NO in human umbilical vein ECs and bovine aortic ECs. The eNOS phosphorylation was also observed in mouse aortas ex vivo perfused with ghrelin and in aortic tissues isolated from mice injected with ghrelin. Mechanistically, ghrelin stimulated AMP-activated protein kinase (AMPK) and Akt activation in cultured ECs and intact vessels. Inhibiting AMPK and Akt with their pharmacological inhibitors, small interference RNA and adenoviruses carried dominant-negative mutants, markedly attenuated ghrelin-induced eNOS activation, and NO production. Furthermore, ghrelin receptor/Gq protein/calcium-dependent pathway mediates activation of AMPK, Akt, and eNOS, and calmodulin-dependent kinase kinase is a potential convergent point to regulate Akt and AMPK activation in ghrelin signaling. Importantly, eNOS activation is critical for ghrelin inhibition of vascular inflammation. Together, both in vitro and in vivo data demonstrate a new role of ghrelin signaling for eNOS activation, and highlight the therapeutic potential for ghrelin to correct endothelial dysfunction associated with atherosclerotic vascular diseases and metabolic syndrome.
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Affiliation(s)
- Xiangbin Xu
- Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 679, Rochester, New York 14642, USA
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Haxhija EQ, Yang H, Spencer AU, Koga H, Sun X, Teitelbaum DH. Modulation of mouse intestinal epithelial cell turnover in the absence of angiotensin converting enzyme. Am J Physiol Gastrointest Liver Physiol 2008; 295:G88-G98. [PMID: 18483182 PMCID: PMC2494725 DOI: 10.1152/ajpgi.00589.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Angiotensin converting enzyme (ACE) has been shown to be involved in regulation of apoptosis in nonintestinal tissues. This study examined the role of ACE in the modulation of intestinal adaptation utilizing ACE knockout mice (ACE-/-). A 60% small bowel resection (SBR) was used, since this model results in a significant increase in intestinal epithelial cell (EC) apoptosis as well as proliferation. Baseline villus height, crypt depth, and intestinal EC proliferation were higher, and EC apoptosis rates were lower in ACE-/- compared with ACE+/+ mice. After SBR, EC apoptosis rates remained significantly lower in ACE-/- compared with ACE+/+ mice. Furthermore, villus height and crypt depth after SBR continued to be higher in ACE-/- mice. The finding of a lower bax-to-bcl-2 protein ratio in ACE-/- mice may account for reduced EC apoptotic rates after SBR in ACE-/- compared with ACE+/+ mice. The baseline higher rate of EC proliferation in ACE-/- compared with ACE+/+ mice may be due to an increase in the expression of several EC growth factor receptors. In conclusion, ACE appears to have an important role in the modulation of intestinal EC apoptosis and proliferation and suggests that the presence of ACE in the intestinal epithelium has a critical role in guiding epithelial cell adaptive response.
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Affiliation(s)
- Emir Q. Haxhija
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, and C. S. Mott Children's Hospital, Ann Arbor, Michigan; and Department of Pediatric Surgery, Medical University Graz, Graz, Austria
| | - Hua Yang
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, and C. S. Mott Children's Hospital, Ann Arbor, Michigan; and Department of Pediatric Surgery, Medical University Graz, Graz, Austria
| | - Ariel U. Spencer
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, and C. S. Mott Children's Hospital, Ann Arbor, Michigan; and Department of Pediatric Surgery, Medical University Graz, Graz, Austria
| | - Hiroyuki Koga
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, and C. S. Mott Children's Hospital, Ann Arbor, Michigan; and Department of Pediatric Surgery, Medical University Graz, Graz, Austria
| | - Xiaoyi Sun
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, and C. S. Mott Children's Hospital, Ann Arbor, Michigan; and Department of Pediatric Surgery, Medical University Graz, Graz, Austria
| | - Daniel H. Teitelbaum
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School, and C. S. Mott Children's Hospital, Ann Arbor, Michigan; and Department of Pediatric Surgery, Medical University Graz, Graz, Austria
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Johansson I, Destefanis S, Aberg ND, Aberg MAI, Blomgren K, Zhu C, Ghè C, Granata R, Ghigo E, Muccioli G, Eriksson PS, Isgaard J. Proliferative and protective effects of growth hormone secretagogues on adult rat hippocampal progenitor cells. Endocrinology 2008; 149:2191-9. [PMID: 18218693 DOI: 10.1210/en.2007-0733] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Progenitor cells in the subgranular zone of the hippocampus may be of significance for functional recovery after various injuries because they have a regenerative potential to form new neuronal cells. The hippocampus has been shown to express the GH secretagogue (GHS) receptor 1a, and recent studies suggest GHS to both promote neurogenesis and have neuroprotective effects. The aim of the present study was to investigate whether GHS could stimulate cellular proliferation and exert cell protective effects in adult rat hippocampal progenitor (AHP) cells. Both hexarelin and ghrelin stimulated increased incorporation of (3)H-thymidine, indicating an increased cell proliferation. Furthermore, hexarelin, but not ghrelin, showed protection against growth factor deprivation-induced apoptosis, as measured by annexin V binding and caspase-3 activity and also against necrosis, as measured by lactate dehydrogenase release. Hexarelin activated the MAPK and the phosphatidylinositol 3-kinase/Akt pathways, whereas ghrelin activated only the MAPK pathway. AHP cells did not express the GHS receptor 1a, but binding studies could show specific binding of both hexarelin and ghrelin, suggesting effects to be mediated by an alternative GHS receptor subtype. In conclusion, our results suggest a differential effect of hexarelin and ghrelin in AHP cells. We have demonstrated stimulation of (3)H-thymidine incorporation with both hexarelin and ghrelin. Hexarelin, but not ghrelin, also showed a significant inhibition of apoptosis and necrosis. These results suggest a novel cell protective and proliferative role for GHS in the central nervous system.
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Affiliation(s)
- Inger Johansson
- Laboratory of Experimental Endocrinology, Sahlgrenska Academy, University of Göteborg, SE-413 45 Göteborg, Sweden.
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Wildhaber BE, Yang H, Haxhija EQ, Spencer AU, Teitelbaum DH. Intestinal intraepithelial lymphocyte derived angiotensin converting enzyme modulates epithelial cell apoptosis. Apoptosis 2008; 10:1305-15. [PMID: 16215678 PMCID: PMC1351359 DOI: 10.1007/s10495-005-2138-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Intestinal adaptation in short bowel syndrome (SBS) consists of increased epithelial cell (EC) proliferation as well as apoptosis. Previous microarray analyses of intraepithelial lymphocytes (IEL) gene expression after SBS showed an increased expression of angiotensin converting enzyme (ACE). Because ACE has been shown to promote alveolar EC apoptosis, we examined if IEL-derived ACE plays a role in intestinal EC apoptosis. METHODS Mice underwent either a 70% mid-intestinal resection (SBS group) or a transection (Sham group) and were studied at 7 days. ACE expression was measured, and ACE inhibition (ACE-I, enalaprilat) was used to assess ACE function. RESULTS IEL-derived ACE was significantly elevated in SBS mice. The addition of an ACE-I to SBS mice resulted in a significant decline in EC apoptosis. To address a possible mechanism, tumor necrosis factor alpha (TNF-alpha) mRNA expression was measured. TNF-alpha was significantly increased in SBS mice, and decreased with ACE-I. Interestingly, ACE-I was not able to decrease EC apoptosis in TNF-alpha knockout mice. CONCLUSIONS This study shows a previously undescribed expression of ACE by IEL. SBS was associated with an increase in IEL-derived ACE. ACE appears to be associated with an up-regulation of intestinal EC apoptosis. ACE-I significantly decreased EC apoptosis.
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Affiliation(s)
| | | | | | | | - Daniel H. Teitelbaum
- Correspondence to: Daniel H. Teitelbaum, MD, Section of Pediatric Surgery, University of Michigan Hospitals, Mott F3970, Box 0245, Ann Arbor, MI, 48109, USA, Phone: 734 764 4151, fax :734 936 9784 e-mail:
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Li Q, Yang X, Sreejayan N, Ren J. Insulin-like growth factor I deficiency prolongs survival and antagonizes paraquat-induced cardiomyocyte dysfunction: role of oxidative stress. Rejuvenation Res 2008; 10:501-12. [PMID: 17979500 DOI: 10.1089/rej.2007.0552] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Interruption of insulin-like growth factor I (IGF-1) signaling has been demonstrated to prolong life span although the underlying mechanism has not been elucidated. The aim of this study was to examine the influence of severe IGF-1 deficiency on survival rate, cardiomyocyte viability, contractile function, and intracellular Ca(2+) property in response to challenge with the pro-oxidant paraquat. C57 negative and liver IGF-1 deficient (LID) transgenic mice were administrated paraquat (75 mg/kg) and survival was monitored. LID mice displayed a significantly improved survival than did C57 mice evaluated by the Kaplan-Meier curve. MTT assay revealed that in vitro IGF-1 treatment significantly sensitized paraquat-induced cell death in both C57 and LID groups, with significantly better cell viability in LID cardiomyocytes. Compared to C57 mouse cardiomyocytes, LID myocytes displayed reduced peak shortening (PS), decreased maximal velocity of shortening/relengthening (+/- dL/dt), prolonged time-to-90% relengthening (TR(90)), and comparable tolerance to high stimulus frequency and intracellular Ca(2+) homeostasis. Paraquat treatment for 48 hours reduced PS, +/- dL/dt, tolerance to high stimulus frequency, resting and rise in intracellular Ca(2+), and prolonged TR(90), all of which were nullified or masked by IGF-1 deficiency. Paraquat increased reactive oxygen species and carbonyl production upregulated the Ca(2+) regulating protein SERCA2a, and downregulated Na(+) -Ca(2+) exchanger, the effects of which were nullified or masked by IGF-1 deficiency. Although LID mice displayed reduced whole body glucose clearance, cardiomyocytes from LID mice exhibited dramatically enhanced insulin-stimulated phosphorylation of insulin receptor and Akt. These data demonstrated that IGF-1 deficiency may antagonize or mask the paraquat-induced decrease in survival, cardiomyocyte dysfunction, oxidative stress, and change in Ca(2+) regulating proteins.
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Affiliation(s)
- Qun Li
- Division of Pharmaceutical Sciences, Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
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Yang QH, Xu JN, Xu RK, Pang SF. Antiproliferative effects of melatonin on the growth of rat pituitary prolactin-secreting tumor cells in vitro. J Pineal Res 2007; 42:172-9. [PMID: 17286750 DOI: 10.1111/j.1600-079x.2006.00403.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Earlier studies showed that melatonin reduced the growth of 17-beta-estradiol (E(2))-induced rat pituitary prolactin-secreting tumor (prolactinoma) in vivo. The mechanisms of melatonin's inhibitory action on the prolactin-secreting tumor were further explored by investigating the in vitro effects of melatonin on the growth of pituitary prolactin-secreting tumor cells. Primary cultured prolactinoma cells from E(2)-induced rat pituitary prolactin-secreting tumor were treated with 10(-5), 10(-4) or 10(-3) m melatonin for 5 days. Apoptosis was evaluated using flow cytometry and the TdT-mediated dUTP nick-end labeling (TUNEL) method. In addition, cell viability was analyzed by (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It was found that incubation of prolactinoma cells with 10(-5), 10(-4) or 10(-3) m melatonin for 5 days inhibited cell growth and increased cell apoptosis. Furthermore, melatonin increased caspase-3 activity, Bax mRNA expression, and cytochrome c protein expression. Conversely, Bcl-2 mRNA expression and mitochondrial membrane potential were inhibited by melatonin treatment. Our results further suggest that melatonin inhibits tumor growth by inducing apoptosis of rat pituitary prolactin-secreting tumor directly via the damage of mitochondria.
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Affiliation(s)
- Quan-Hui Yang
- Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China
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Chung H, Kim E, Lee DH, Seo S, Ju S, Lee D, Kim H, Park S. Ghrelin inhibits apoptosis in hypothalamic neuronal cells during oxygen-glucose deprivation. Endocrinology 2007; 148:148-59. [PMID: 17053024 DOI: 10.1210/en.2006-0991] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ghrelin is an endogenous ligand for the GH secretagogue receptor, produced and secreted mainly from the stomach. Ghrelin stimulates GH release and induces positive energy balances. Previous studies have reported that ghrelin inhibits apoptosis in several cell types, but its antiapoptotic effect in neuronal cells is unknown. Therefore, we investigated the role of ghrelin in ischemic neuronal injury using primary hypothalamic neurons exposed to oxygen-glucose deprivation (OGD). Here we report that treatment of hypothalamic neurons with ghrelin inhibited OGD-induced cell death and apoptosis. Exposure of neurons to ghrelin caused rapid activation of ERK1/2. Ghrelin-induced activation of ERK1/2 and the antiapoptotic effect of ghrelin were blocked by chemical inhibition of MAPK, phosphatidylinositol 3 kinase, protein kinase C, and protein kinase A. Ghrelin attenuated OGD-induced activation of c-Jun NH2-terminal kinase and p-38 but not ERK1/2. We also investigated ghrelin regulation of apoptosis at the mitochondrial level. Ghrelin protected cells from OGD insult by inhibiting reactive oxygen species generation and stabilizing mitochondrial transmembrane potential. In addition, ghrelin-treated cells showed an increased Bcl-2/Bax ratio, prevention of cytochrome c release, and inhibition of caspase-3 activation. Finally, in vivo administration of ghrelin significantly reduced infarct volume in an animal model of ischemia. Our data indicate that ghrelin may act as a survival factor that preserves mitochondrial integrity and inhibits apoptotic pathways.
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Affiliation(s)
- Hyunju Chung
- Department of Pharmacology, Kyunghee University School of Medicine, Dongdaemun-ku, Seoul 130-701, Korea
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Gupta MK, Neelakantan TV, Sanghamitra M, Tyagi RK, Dinda A, Maulik S, Mukhopadhyay CK, Goswami SK. An assessment of the role of reactive oxygen species and redox signaling in norepinephrine-induced apoptosis and hypertrophy of H9c2 cardiac myoblasts. Antioxid Redox Signal 2006; 8:1081-93. [PMID: 16771697 DOI: 10.1089/ars.2006.8.1081] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cardiac myocytes, upon exposure to increasing doses of norepinephrine (NE), transit from hypertrophic to apoptotic phenotype. Since reactive oxygen species (ROS) generation is attributed to both phenomena, the authors tested whether an elevation in intracellular ROS level causes such transition. H9c2 cardiac myoblasts upon treatment with hypertrophic and apoptotic doses of NE (2 and 100 microM, respectively) transiently induced intracellular ROS at a comparable level, while 200 microM H(2)O(2), another proapoptotic agonist, showed robust and sustained ROS generation. Upon analysis of a number of redox-responsive transcription factors as the downstream targets of ROS signaling, the authors observed that NE (2 and 100 microM) and H(2)O(2) (200 microM) were ineffective in inducing NF-kappaB while both the agonists upregulated AP-1 and Nrf-2. However, the extents of induction of AP-1 and Nrf-2 were not in direct correlation with the respective ROS levels. Also, AP-1 activities induced by two doses of NE were intrinsically different, since at 2 microM, it primarily induced FosB, and at 100 microM it activated Fra-1. Differential induction of FosB and Fra-1 was also reiterated in adult rat myocardium injected with increasing doses of NE. Therefore, NE induces hypertrophy and apoptosis in cardiac myocytes by distinct redox-signaling rather than a general surge of ROS.
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Affiliation(s)
- Manveen K Gupta
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
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Qin F, Patel R, Yan C, Liu W. NADPH oxidase is involved in angiotensin II-induced apoptosis in H9C2 cardiac muscle cells: effects of apocynin. Free Radic Biol Med 2006; 40:236-46. [PMID: 16413406 DOI: 10.1016/j.freeradbiomed.2005.08.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2004] [Revised: 07/17/2005] [Accepted: 08/05/2005] [Indexed: 11/26/2022]
Abstract
Angiotensin II stimulates NADPH oxidase activity in vascular cells. However, it is not fully understood whether angiotensin II, which plays an important role in heart failure, stimulates NADPH oxidase activation and expression in cardiac myocytes. Previous studies have shown that angiotensin II induces myocyte apoptosis, but whether the change is mediated via NADPH oxidase remains to be elucidated. In this study we proposed to determine whether angiotensin II stimulated NADPH oxidase activation and NADPH oxidase subunit p47-phox expression in H9C2 cardiac muscle cells. If so, we would determine whether the NADPH oxidase inhibitor apocynin prevented angiotensin II-induced apoptosis. The results showed that angiotensin II increased NADPH oxidase activity, p47-phox protein and mRNA expression, intracellular reactive oxygen species, and apoptosis in H9C2 cells. Angiotensin II elevated p38 mitogen-activated protein kinase (MAPK) activity, decreased Bcl-2 protein, and increased Bax protein and caspase-3 activity. Apocynin treatment inhibited angiotensin II-induced NADPH oxidase activation and increases in p47-phox expression, intracellular reactive oxygen species, and apoptosis. The effect of apocynin on apoptosis was associated with reduced p38 MAPK activity, increased Bcl-2 protein, and decreased Bax protein and caspase-3 activity. These results suggest that angiotensin II-induced apoptosis is mediated via NADPH oxidase activation probably through p38 MAPK activation, a decrease in Bcl-2 protein, and caspase activation.
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Affiliation(s)
- Fuzhong Qin
- Cardiology Unit, Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
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Cao JM, Ong H, Chen C. Effects of ghrelin and synthetic GH secretagogues on the cardiovascular system. Trends Endocrinol Metab 2006; 17:13-8. [PMID: 16309920 DOI: 10.1016/j.tem.2005.11.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Revised: 09/29/2005] [Accepted: 11/14/2005] [Indexed: 02/06/2023]
Abstract
Ghrelin, a newly discovered endogenous hormone that is produced by the stomach, and synthetic peptides have been identified recently as potent growth-hormone secretagogues. This effect is exerted through interaction with a specific G-protein-coupled receptor, GHS-R1a, which is expressed mainly in the hypothalamus-pituitary complex. A study of the peripheral distribution of GHS receptors has shown that it is also present in cardiovascular tissue, which has led to the exploration of the cardiovascular functions of ghrelin and synthetic, growth-hormone-releasing peptides. These ligands have several cardiovascular activities, including a cardioprotective effect against myocardial ischemia, and vasoactive and cardiotropic effects in both experimental models and humans. These effects are mediated by the interaction of these ligands with binding sites, including GHS-1Ra, for which the signalling pathways are not documented fully. Identification of the cardiac and vascular binding sites for ghrelin and synthetic, growth-hormone-releasing peptides will provide new perspectives for treating cardiovascular diseases with these ligands.
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Affiliation(s)
- Ji-Min Cao
- Department of Physiology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing 100730, People's Republic of China
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Brywe KG, Leverin AL, Gustavsson M, Mallard C, Granata R, Destefanis S, Volante M, Hagberg H, Ghigo E, Isgaard J. Growth hormone-releasing peptide hexarelin reduces neonatal brain injury and alters Akt/glycogen synthase kinase-3beta phosphorylation. Endocrinology 2005; 146:4665-72. [PMID: 16081643 DOI: 10.1210/en.2005-0389] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hexarelin (HEX) is a peptide GH secretagogue with a potent ability to stimulate GH secretion and recently reported cardioprotective actions. However, its effects in the brain are largely unknown, and the aim of the present study was to examine the potential protective effect of HEX on the central nervous system after injury, as well as on caspase-3, Akt, and extracellular signal-regulated protein kinase (ERK) signaling cascades in a rat model of neonatal hypoxia-ischemia. Hypoxic-ischemic insult was induced by unilateral carotid ligation and hypoxic exposure (7.7% oxygen), and HEX treatment was administered intracerebroventricularly, directly after the insult. Brain damage was quantified at four coronal levels and by regional neuropathological scoring. Brain damage was reduced by 39% in the treatment group, compared with vehicle group, and injury was significantly reduced in the cerebral cortex, hippocampus, and thalamus but not in the striatum. The cerebroprotective effect was accompanied by a significant reduction of caspase-3 activity and an increased phosphorylation of Akt and glycogen synthase kinase-3beta, whereas ERK was unaffected. In conclusion, we demonstrate for the first time that HEX is neuroprotective in the neonatal setting in vivo and that increased Akt signaling is associated with downstream attenuation of glycogen synthase kinase-3beta activity and caspase-dependent cell death.
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Affiliation(s)
- Katarina G Brywe
- Perinatal Center, Department of Obstetrics and Gynecology, Sahlgrenska Academy, Box 432, 405 30 Göteborg, Sweden.
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Abstract
Although initially recognised for their GH-releasing properties, the cardiovascular system has been recognised as a potentially important target for GH secretagogues (GHS). Moreover, a limited number of studies also indicate cardiovascular effects of ghrelin. So far reported cardiovascular effects of GHS and/or ghrelin include lowering of peripheral resistance, possible improvement of contractility and cardioprotective effects both in vivo and in vitro. Taken together, these results offer an interesting perspective on the future where further studies aiming at evaluating a role of GHS and ghrelin in the treatment of cardiovascular disease are warranted.
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Affiliation(s)
- J Isgaard
- Research Center for Endocrinology and Metabolism, Department of Internal Medicine, Sahlgrenska Academy, University of Göteborg, Sweden.
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