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Owesny P, Grune T. The link between obesity and aging - insights into cardiac energy metabolism. Mech Ageing Dev 2023; 216:111870. [PMID: 37689316 DOI: 10.1016/j.mad.2023.111870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
Obesity and aging are well-established risk factors for a range of diseases, including cardiovascular diseases and type 2 diabetes. Given the escalating prevalence of obesity, the aging population, and the subsequent increase in cardiovascular diseases, it is crucial to investigate the underlying mechanisms involved. Both aging and obesity have profound effects on the energy metabolism through various mechanisms, including metabolic inflexibility, altered substrate utilization for energy production, deregulated nutrient sensing, and mitochondrial dysfunction. In this review, we aim to present and discuss the hypothesis that obesity, due to its similarity in changes observed in the aging heart, may accelerate the process of cardiac aging and exacerbate the clinical outcomes of elderly individuals with obesity.
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Affiliation(s)
- Patricia Owesny
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany; German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
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2
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Zhang Y, Jia S, Wen G, Xie S, Song Z, Qi M, Liang Y, Bi W, Dong W. Zoledronate Promotes Peri-Implant Osteogenesis in Diabetic Osteoporosis by the AMPK Pathway. Calcif Tissue Int 2023; 113:329-343. [PMID: 37392365 DOI: 10.1007/s00223-023-01112-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/23/2023] [Indexed: 07/03/2023]
Abstract
Together with diabetic osteoporosis (DOP), diabetes patients experience poor peri-implant osteogenesis following implantation for dentition defects. Zoledronate (ZOL) is widely used to treat osteoporosis clinically. To evaluate the mechanism of ZOL for the treatment of DOP, experiments with DOP rats and high glucose-grown MC3T3-E1 cells were used. The DOP rats treated with ZOL and/or ZOL implants underwent a 4-week implant-healing interval, and then microcomputed tomography, biomechanical testing, and immunohistochemical staining were performed to elucidate the mechanism. In addition, MC3T3-E1 cells were maintained in an osteogenic medium with or without ZOL to confirm the mechanism. The cell migration, cellular actin content, and osteogenic differentiation were evaluated by a cell activity assay, a cell migration assay, as well as alkaline phosphatase, alizarin red S, and immunofluorescence staining. The mRNA and protein expression of adenosine monophosphate-activated protein kinase (AMPK), phosphorylated AMPK (p-AMPK), osteoprotegerin (OPG), receptor activator of nuclear factor kappa B ligand (RANKL), bone morphogenetic protein 2 (BMP2), and collagen type I (Col-I) were detected using real-time quantitative PCRs and western blot assays, respectively. In the DOP rats, ZOL markedly improved osteogenesis, enhanced bone strength and increased the expression of AMPK, p-AMPK, and Col-I in peri-implant bones. The in vitro findings showed that ZOL reversed the high glucose-induced inhibition of osteogenesis via the AMPK signaling pathway. In conclusion, the ability of ZOL to promote osteogenesis in DOP by targeting AMPK signaling suggests that therapy with ZOL, particularly simultaneous local and systemic administration, may be a unique approach for future implant repair in diabetes patients.
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Affiliation(s)
- Yan Zhang
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Shunyi Jia
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Guochen Wen
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Shanen Xie
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Zhiqiang Song
- Oral and Maxillofacial Surgery, TangShan BoChuang Stomatology Hospital, Tangshan, 063000, Hebei, China
| | - Mengchun Qi
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Yongqiang Liang
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Wenjuan Bi
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China
| | - Wei Dong
- School of Stomatology, North China University of Science and Technology, Tangshan, 063210, Hebei, China.
- Institute of Stomatology, Chinese PLA General Hospital, Fuxing Lu 28#, Beijing, 100853, China.
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Zhang Y, Nie H, Yan X. Metabolomic analysis provides new insights into the heat-hardening response of Manila clam (Ruditapes philippinarum) to high temperature stress. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159430. [PMID: 36244479 DOI: 10.1016/j.scitotenv.2022.159430] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/15/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The temperature has always been a key environmental factor in Manila clam (Ruditapes philippinarum) culture. In this study, the Manila clam was treated to different temperature pre-heat (28 °C, 30 °C) and gained heat tolerance after recover of 12 h, and a survival rate (14.7 %-49.1 %) advantage after high temperature challenge (30 and 32 °C). To further investigate the physiological and metabolism changes in Manila clam that had experienced a heat stress, non-targeted metabolomics (LC-MS/MS) was used to analyze the metabolic responses of gills in three group Manila clams during the heat challenge. Metabolic profiles revealed that high temperature caused changes in fatty acid composition, energy metabolism, antioxidant metabolites, hydroxyl compounds, and amino acids in heat-hardened clams compared to non-hardened clams. We found a number of significantly enriched pathways, including cAMP signaling pathway, serotonergic synapse, and biosynthesis of unsaturated fatty acids in heat-hardened Manila clam compared with non-hardened and untreated Manila clam. After a brief high temperature treatment, the physiological maintenance ability of Manila clam was improved. Combined with metabolomics analysis, heat hardening treatment may improve the energy metabolism and antioxidant ability of Manila clam. These results provide new insights into the cellular and metabolic responses of Manila clams following high temperature stress.
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Affiliation(s)
- Yanming Zhang
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Hongtao Nie
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China.
| | - Xiwu Yan
- Engineering and Technology Research Center of Shellfish Breeding in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
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Uprety B, Abrahamse H. Targeting Breast Cancer and Their Stem Cell Population through AMPK Activation: Novel Insights. Cells 2022; 11:576. [PMID: 35159385 PMCID: PMC8834477 DOI: 10.3390/cells11030576] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023] Open
Abstract
Despite some significant advancements, breast cancer has become the most prevalent cancer in the world. One of the main reasons for failure in treatment and metastasis has been attributed to the presence of cancer initiating cells-cancer stem cells. Consequently, research is now being focussed on targeting cancer cells along with their stem cell population. Non-oncology drugs are gaining increasing attention for their potent anticancer activities. Metformin, a drug commonly used to treat type 2 diabetes, is the best example in this regard. It exerts its therapeutic action by activating 5' adenosine monophosphate-activated protein kinase (AMPK). Activated AMPK subsequently phosphorylates and targets several cellular pathways involved in cell growth and proliferation and the maintenance of stem-like properties of cancer stem cells. Therefore, AMPK is emerging as a target of choice for developing effective anticancer drugs. Vanadium compounds are well-known PTP inhibitors and AMPK activators. They find extensive applications in treatment of diabetes and obesity via PTP1B inhibition and AMPK-mediated inhibition of adipogenesis. However, their role in targeting cancer stem cells has not been explored yet. This review is an attempt to establish the applications of insulin mimetic vanadium compounds for the treatment of breast cancer by AMPK activation and PTP1B inhibition pathways.
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Affiliation(s)
- Bhawna Uprety
- Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, South Africa;
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Zhang XM, Li YC, Chen P, Ye S, Xie SH, Xia WJ, Yang JH. MG-132 attenuates cardiac deterioration of viral myocarditis via AMPK pathway. Biomed Pharmacother 2020; 126:110091. [PMID: 32278272 DOI: 10.1016/j.biopha.2020.110091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Coxsackievirus B3 (CVB3) is the primary cause of infectious myocarditis. Aggressive immunological activation and apoptosis of myocytes contributes to progressive dysfunction of cardiac contraction and poor prognosis. MG-132, a proteasome inhibitor, regulates mitochondrial-mediated intrinsic myocardial apoptosis and downregulates NF-κB-mediated inflammation. Here, we determined whether AMPK pathway participates in MG-132-mediated myocardial protection in viral-induced myocarditis. METHODS AND RESULTS Acute viral myocarditis models were established by intraperitoneal inoculation of CVB3 in male BALB/c mice. Myocarditis and age-matched control mice were administered MG-132 and/or BML-275 dihydrochloride (BML) (AMPK antagonist) intraperitoneally daily from the day following CVB3 inoculation. MG-132 improved hemodynamics and inhibited the structural remodeling of the ventricle in mice with myocarditis, while BML largely blunted these effects. TUNEL staining and immunochemistry suggested that MG-132 exerts anti-apoptotic and anti-inflammatory effects against CVB3-induced myocardial injuries. BML attenuated the effects of MG-132 on anti-apoptosis and anti-inflammation. CONCLUSION MG-132 modulated apoptosis and inflammation, improved hemodynamics, and inhibited the structural remodeling of ventricles in a myocarditis mouse model via regulation of the AMPK signal pathway.
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Affiliation(s)
- Xin-Min Zhang
- The First Affiliated Hospital of Soochow University, Suzhou, 215006, China; The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Yue-Chun Li
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Peng Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Sheng Ye
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Shang-He Xie
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Wu-Jie Xia
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Jun-Hua Yang
- The First Affiliated Hospital of Soochow University, Suzhou, 215006, China.
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Daniels LJ, Varma U, Annandale M, Chan E, Mellor KM, Delbridge LMD. Myocardial Energy Stress, Autophagy Induction, and Cardiomyocyte Functional Responses. Antioxid Redox Signal 2019; 31:472-486. [PMID: 30417655 DOI: 10.1089/ars.2018.7650] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Significance: Energy stress in the myocardium occurs in a variety of acute and chronic pathophysiological contexts, including ischemia, nutrient deprivation, and diabetic disease settings of substrate disturbance. Although the heart is highly adaptive and flexible in relation to fuel utilization and routes of adenosine-5'-triphosphate (ATP) generation, maladaptations in energy stress situations confer functional deficit. An understanding of the mechanisms that link energy stress to impaired myocardial performance is crucial. Recent Advances: Emerging evidence suggests that, in parallel with regulated enzymatic pathways that control intracellular substrate supply, other processes of "bulk" autophagic macromolecular breakdown may be important in energy stress conditions. Recent findings indicate that cargo-specific autophagic activity may be important in different stress states. In particular, induction of glycophagy, a glycogen-specific autophagy, has been described in acute and chronic energy stress situations. The impact of elevated cardiomyocyte glucose flux relating to glycophagy dysregulation on contractile function is unknown. Critical Issues: Ischemia- and diabetes-related cardiac adverse events comprise the majority of cardiovascular disease morbidity and mortality. Current therapies involve management of systemic comorbidities. Cardiac-specific adjunct treatments targeted to manage myocardial energy stress responses are lacking. Future Directions: New knowledge is required to understand the mechanisms involved in selective recruitment of autophagic responses in the cardiomyocyte energy stress response. In particular, exploration of the links between cell substrate flux, calcium ion (Ca2+) flux, and phagosomal cargo flux is required. Strategies to target specific fuel "bulk" management defects in cardiac energy stress states may be of therapeutic value.
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Affiliation(s)
- Lorna J Daniels
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Upasna Varma
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Marco Annandale
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Eleia Chan
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Kimberley M Mellor
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand.,2 Department of Physiology, University of Melbourne, Melbourne, Australia.,3 Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Lea M D Delbridge
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
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Yang H, Zhu L, Gu Y, Kong X, yan liu, Chen M, Xie X, Luo J, Chen S. Berberine inhibits low shear stress-induced glycocalyx degradation via modulating AMPK and p47phox/Hyal2 signal pathway. Eur J Pharmacol 2019; 856:172413. [DOI: 10.1016/j.ejphar.2019.172413] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/15/2019] [Accepted: 05/22/2019] [Indexed: 12/17/2022]
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Zhang DS, Liang GY, Liu DX, Yu J, Wang F. Role of Phosphorylated AMP-Activated Protein Kinase (AMPK) in Myocardial Insulin Resistance After Myocardial Ischemia-Reperfusion During Cardiopulmonary Bypass Surgery in Dogs. Med Sci Monit 2019; 25:4149-4158. [PMID: 31160548 PMCID: PMC6561136 DOI: 10.12659/msm.916517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Background The aim of this study was to determine the role of AMP-activated protein kinase (AMPK) in myocardial insulin resistance after myocardial ischemia-reperfusion during cardiopulmonary bypass surgery in dogs. Material/Methods Twenty-four mongrel dogs were randomly assigned to 4 groups. The control group did not undergo aortic cross-clamping; the model group underwent 60 mins of aortic cross-clamping with 150 ml cardioplegic solution. The treatment group, the inhibition group respectively with 0.11mg/kg AICAR (AMPK agonist) in 150 ml cardioplegic solution and 0.11 mg/kg Compound C (AMPK inhibitor) in 150 ml cardioplegic solution. The blood flow was determined and left ventricular myocardial tissue were taken at pre-bypass, 15, 60, and 90 min after aorta declamping, respectively. Expression of AMPK mRNA, p-AMPK and GLUT-4 proteins was determined by RT-PCR, IHC and WB. Results Compared with the control group, receiving 60 min ischemia at 15 min after reperfusion, Myocardial Glucose Extraction Ratio were significantly decreased in the other 3 groups, it was significantly decreased from 20.0% to 1.2% at 60 min of reperfusion, and recovered to 6.1% after 90 min reperfusion in model group, while recovered to 4.1%, 12.0% after 90 min reperfusion respectively exposed to Compound C and AICAR. The expressions of p-AMPK, GLUT-4 protein and AMPK mRNA in myocardium were decreased in different experiment groups, but these changes occurred to a lesser extent in the treatment group. Conclusions The inability of GLUT-4 expression induced by the decreases in p-AMPK protein expression that may be one of the reasons for myocardial insulin resistance.
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Affiliation(s)
- Deng-Shen Zhang
- Department of Thoracic and Cardiovascular Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China (mainland)
| | - Gui-You Liang
- Department of Thoracic and Cardiovascular Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China (mainland)
| | - Da-Xing Liu
- Department of Thoracic and Cardiovascular Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China (mainland)
| | - Jie Yu
- School of Public Health, Zunyi Medical University, Zunyi, Guizhou, China (mainland)
| | - Feng Wang
- Department of Thoracic and Cardiovascular Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China (mainland)
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Miyamoto L. Molecular Pathogenesis of Familial Wolff-Parkinson-White Syndrome. THE JOURNAL OF MEDICAL INVESTIGATION 2018; 65:1-8. [PMID: 29593177 DOI: 10.2152/jmi.65.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Familial Wolff-Parkinson-White (WPW) syndrome is an autosomal dominant inherited disease and consists of a small percentage of WPW syndrome which exhibits ventricular pre-excitation by development of accessory atrioventricular pathway. A series of mutations in PRKAG2 gene encoding gamma2 subunit of 5'AMP-activated protein kinase (AMPK) has been identified as the cause of familial WPW syndrome. AMPK is one of the most important metabolic regulators of carbohydrates and lipids in many types of tissues including cardiac and skeletal muscles. Patients and animals with the mutation in PRKAG2 gene exhibit aberrant atrioventricular conduction associated with cardiac glycogen overload. Recent studies have revealed "novel" significance of canonical pathways leading to glycogen synthesis and provided us profound insights into molecular mechanism of the regulation of glycogen metabolism by AMPK. This review focuses on the molecular basis of the pathogenesis of cardiac abnormality due to PRKAG2 mutation and will provide current overviews of the mechanism of glycogen regulation by AMPK. J. Med. Invest. 65:1-8, February, 2018.
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Varjabedian L, Bourji M, Pourafkari L, Nader ND. Cardioprotection by Metformin: Beneficial Effects Beyond Glucose Reduction. Am J Cardiovasc Drugs 2018; 18:181-193. [PMID: 29478240 DOI: 10.1007/s40256-018-0266-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metformin is a biguanide that is widely used as an insulin-sparing agent to treat diabetes. When compared with the general population, diabetics are twice as likely to die from fatal myocardial infarction and congestive heart failure (CHF). There has been a significant concern regarding the use of metformin in patients with CHF because of their higher tendency to develop lactic acidosis. However, large epidemiological trials have reported better cardiovascular prognosis with metformin compared to other glucose-lowering agents among diabetics. Additionally, metformin has reduced the risk of reinfarction and all-cause mortality in patients with coronary artery disease and CHF, respectively. The protection against cardiovascular diseases appears to be independent of the anti-hyperglycemic effects of metformin. These effects are mediated through an increase in 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and by increased phosphorylation of endothelial nitric oxide synthase (eNOS) in cardiomyocytes with an increased production of nitric oxide (NO). Metformin preconditions the heart against ischemia-reperfusion injury and may improve myocardial remodeling after an ischemic insult. The preponderance of evidence currently suggests that metformin is safe in patients with CHF, prompting the Food and Drug Administration to remove CHF as a contraindication from the package insert of all generic metformin preparations. In this narrative, along with a limited meta-analysis of available studies, we have reviewed the pleiotropic (non-glucose-lowering) effects of metformin that potentially contribute to its cardioprotective properties. Additionally, we have reviewed issues surrounding the safety of metformin in patients with cardiac diseases.
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Affiliation(s)
| | - Mohammad Bourji
- Department of Medicine, University at Buffalo, Buffalo, NY, 14203, USA
| | - Leili Pourafkari
- Department of Anesthesiology, University at Buffalo, 77 Goodell Street # 550, Buffalo, NY, 14203, USA
| | - Nader D Nader
- Department of Anesthesiology, University at Buffalo, 77 Goodell Street # 550, Buffalo, NY, 14203, USA.
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Qiu F, Zhang H, Yuan Y, Liu Z, Huang B, Miao H, Liu X, Zhao Q, Zhang H, Dong H, Zhang Z. A decrease of ATP production steered by PEDF in cardiomyocytes with oxygen-glucose deprivation is associated with an AMPK-dependent degradation pathway. Int J Cardiol 2018; 257:262-271. [PMID: 29361350 DOI: 10.1016/j.ijcard.2018.01.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/08/2018] [Indexed: 01/01/2023]
Abstract
AIMS The activated AMP activated protein kinase (AMPK) serves as a transient protective cardiovascular kinase via preserving adenosine triphosphate (ATP) production under ischemic conditions. However, recent studies reveal that inhibition of AMPK in stroke is neuroprotection. Pigment epithelium derived factor (PEDF) is also known for the protection of ischemic cardiomyocytes. However, the relationship between PEDF and AMPK in cardiomyocytes is poorly understood. METHODS AND RESULTS Rat neonatal and adult left ventricular cardiomyocytes were isolated and subjected to oxygen-glucose deprivation (OGD). During OGD, PEDF significantly reduced AMPKα levels to decrease ATP production and reduced ATP expenditure both in neonatal and adult cardiomyocytes, which increased energy reserves and cell viability. Importantly, pharmacological AMPK inhibitor reduced ATP production but failed to decrease ATP expenditure, thus leading cells into death. Furthermore, AMPKα was degraded by a ubiquitin-dependent proteasomal degradation pathway, which is associated with a PEDF/PEDFR/peroxisome proliferator activated receptor γ (PPARγ) axis. Inhibition of PPARγ or proteasome disrupted the interaction of AMPKα and PPARγ, which abolished AMPKα degradation. Importantly, the decrease of AMPKα and ATP level was normalized after recovery of oxygen and glucose. CONCLUSIONS We demonstrate a novel mechanism for regulation of cardiac ATP production by PEDF involving AMPKα and PPARγ. PEDF promotes proteasomal degradation of AMPK and, subsequently, reduces ATP production. The reduction of ATP production associated with the decrease of ATP expenditure completed by PEDF increase energy reserves and reduces cell energy failure, prolonging the cell activity during OGD.
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Affiliation(s)
- Fan Qiu
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Hao Zhang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Yanliang Yuan
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Zhiwei Liu
- Morphological Research Experiment Center, Xuzhou Medical University, 209 Tongshan Road, Xuzhou 221004, Jiangsu, China
| | - Bing Huang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Haoran Miao
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Xiucheng Liu
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Qixiang Zhao
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Hu Zhang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China
| | - Hongyan Dong
- Morphological Research Experiment Center, Xuzhou Medical University, 209 Tongshan Road, Xuzhou 221004, Jiangsu, China.
| | - Zhongming Zhang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou 221006, Jiangsu, China.
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Hermann R, Mestre Cordero VE, Fernández Pazos MDLM, Reznik FJ, Vélez DE, Savino EA, Marina Prendes MG, Varela A. Differential effects of AMP-activated protein kinase in isolated rat atria subjected to simulated ischemia-reperfusion depending on the energetic substrates available. Pflugers Arch 2017; 470:367-383. [PMID: 29032506 DOI: 10.1007/s00424-017-2075-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/24/2017] [Accepted: 09/28/2017] [Indexed: 12/31/2022]
Abstract
AMP-activated protein kinase (AMPK) is a serine-threonine kinase that functions primarily as a metabolic sensor to coordinate anabolic and catabolic processes in the cell, via phosphorylation of multiple proteins involved in metabolic pathways, aimed to re-establish energy homeostasis at a cell-autonomous level. Myocardial ischemia and reperfusion represents a metabolic stress situation for myocytes. Whether AMPK plays a critical role in the metabolic and functional responses involved in these conditions remains uncertain. In this study, in order to gain a deeper insight into the role of endogenous AMPK activation during myocardial ischemia and reperfusion, we explored the effects of the pharmacological inhibition of AMPK on contractile function rat, contractile reserve, tissue lactate production, tissue ATP content, and cellular viability. For this aim, isolated atria subjected to simulated 75 min ischemia-75 min reperfusion (Is-Rs) in the presence or absence of the pharmacological inhibitor of AMPK (compound C) were used. Since in most clinical situations of ischemia-reperfusion the heart is exposed to high levels of fatty acids, the influence of palmitate present in the incubation medium was also investigated. The present results suggest that AMPK activity significantly increases during Is, remaining activated during Rs. The results support that intrinsic activation of AMPK has functional protective effects in the reperfused atria when glucose is the only available energetic substrate whereas it is deleterious when palmitate is also available. Cellular viability was not affected by either of these conditions.
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Affiliation(s)
- Romina Hermann
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina.
| | - Victoria Evangelina Mestre Cordero
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
| | - María de Las Mercedes Fernández Pazos
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
| | - Federico Joaquín Reznik
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
| | - Débora Elisabet Vélez
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
| | - Enrique Alberto Savino
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
| | - María Gabriela Marina Prendes
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
| | - Alicia Varela
- Physiology Unit, Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, Junín, 956, Buenos Aires, Argentina
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Xing T, Zhao X, Wang P, Chen H, Xu X, Zhou G. Different oxidative status and expression of calcium channel components in stress-induced dysfunctional chicken muscle. J Anim Sci 2017; 95:1565-1573. [PMID: 28464077 DOI: 10.2527/jas.2016.0868] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The objective of this study was to assess the effects of transport stress at high ambient temperatures on the oxidation status and the expression of essential elements responsible for the Ca transport (sarco- (endo-) plasmic reticulum Ca-ATPase (SERCA1) and the ryanodine receptor (RyR) in (PM) muscles of broilers. Briefly, Arbor Acres broiler chickens ( = 112) were randomly categorized into 2 treatments: unstressed control (C) and 0.5 h transport (T). Each treatment consisted of 8 replicates of 7 birds each. Birds were transported according to a designed protocol. PM muscle samples in T group were collected and classified as normal (T-NOR) or pale, soft, and exudative-like (T-PSE) using meat quality parameters. The results indicated that production of corticosterone (CORT) and reactive oxygen species (ROS) increased significantly after transportation ( < 0.05). Thiobarbituric acid reactive substance values and carbonyl contents increased significantly in the T group ( < 0.05). Moreover, the extent of lipid peroxidation and protein oxidation was more severe in the T-PSE group compared to the T-NOR group ( < 0.05). The mRNA and protein expression of SERCA1 and αRyR increased in the T-NOR group but decreased significantly in the T-PSE group compared to the CON group ( < 0.05). The mRNA expression of βRyR was found to be enhanced in the T-NOR group compared to the CON group, whereas there was no difference in the T-PSE group ( < 0.05). The results indicate that short-distance transport of broilers affects their physiological responses and biochemical changes which may lead to different oxidative states and, importantly, to different expressions of SERCA and RyR. These induced changes in abnormal sarcoplasmic Ca homeostasis have significant implications for the development of PSE-like meat.
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Bairwa SC, Parajuli N, Dyck JRB. The role of AMPK in cardiomyocyte health and survival. Biochim Biophys Acta Mol Basis Dis 2016; 1862:2199-2210. [PMID: 27412473 DOI: 10.1016/j.bbadis.2016.07.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/05/2016] [Accepted: 07/05/2016] [Indexed: 01/09/2023]
Abstract
Cellular energy homeostasis is a fundamental process that governs the overall health of the cell and is paramount to cell survival. Central to this is the control of ATP generation and utilization, which is regulated by a complex myriad of enzymatic reactions controlling cellular metabolism. In the cardiomyocyte, ATP generated from substrate catabolism is used for numerous cellular processes including maintaining ionic homeostasis, cell repair, protein synthesis and turnover, organelle turnover, and contractile function. In many instances, cardiovascular disease is associated with impaired cardiac energetics and thus the signalling that regulates pathways involved in cardiomyocyte metabolism may be potential targets for pharmacotherapy designed to help treat cardiovascular disease. An important regulator of cardiomyocyte energy homeostasis is adenosine monophosphate-activated protein kinase (AMPK). AMPK is a serine-threonine kinase that functions primarily as a metabolic sensor to coordinate anabolic and catabolic activities in the cell via the phosphorylation of multiple proteins involved in metabolic pathways. In addition to the direct role that AMPK plays in the regulation of cardiomyocyte metabolism, AMPK can also either directly or indirectly influence other cellular processes such as regulating mitochondrial function, post-translation acetylation, autophagy, mitophagy, endoplasmic reticulum stress, and apoptosis. Thus, AMPK is implicated in the control of a wide variety of cellular processes that can influence cardiomyocyte health and survival. In this review, we will discuss the important role that AMPK plays in regulating cardiac metabolism, as well as the additional cellular processes that may contribute to cardiomyocyte function and survival in the healthy and the diseased heart. This article is part of a Special Issue entitled: The role of post-translational protein modifications on heart and vascular metabolism edited by Jason R.B. Dyck & Jan. F.C. Glatz.
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Affiliation(s)
- Suresh C Bairwa
- Department of Medicine, Faculty of Medicine and Dentistry, Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Nirmal Parajuli
- Department of Medicine, Faculty of Medicine and Dentistry, Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Jason R B Dyck
- Department of Medicine, Faculty of Medicine and Dentistry, Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada.
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15
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Liver Kinase B1 complex acts as a novel modifier of myofilament function and localizes to the Z-disk in cardiac myocytes. Arch Biochem Biophys 2016; 601:32-41. [PMID: 26971467 DOI: 10.1016/j.abb.2016.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/09/2016] [Accepted: 03/08/2016] [Indexed: 01/15/2023]
Abstract
Contractile perturbations downstream of Ca(2+) binding to troponin C, the so-called sarcomere-controlled mechanisms, represent the earliest indicators of energy remodeling in the diseased heart [1]. Central to cellular energy "sensing" is the adenosine monophosphate-activated kinase (AMPK) pathway, which is known to directly target myofilament proteins and alter contractility [2-6]. We previously showed that the upstream AMPK kinase, LKB1/MO25/STRAD, impacts myofilament function independently of AMPK [5]. Therefore, we hypothesized that the LKB1 complex associated with myofilament proteins and that alterations in energy signaling modulated targeting or localization of the LKB1 complex to the myofilament. Using an integrated strategy of myofilament mechanics, immunoblot analysis, co-immunoprecipitation, mass spectroscopy, and immunofluorescence, we showed that 1) LKB1 and MO25 associated with myofibrillar proteins, 2) cellular energy stress re-distributed AMPK/LKB1 complex proteins within the sarcomere, and 3) the LKB1 complex localized to the Z-Disk and interacted with cytoskeletal and energy-regulating proteins, including vinculin and ATP Synthase (Complex V). These data represent a novel role for LKB1 complex proteins in myofilament function and myocellular "energy" sensing in the heart.
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16
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Jiang S, Jiang D, Zhao P, He X, Tian S, Wu X, Tao Y. Activation of AMP-activated protein kinase reduces collagen production via p38 MAPK in cardiac fibroblasts induced by coxsackievirus B3. Mol Med Rep 2016; 14:989-94. [PMID: 27221787 DOI: 10.3892/mmr.2016.5319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 04/26/2016] [Indexed: 11/05/2022] Open
Abstract
Collagen deposition is the major cause of myocardial fibrosis, contributing to impaired cardiac contractile function in coxsackie virus B3 (CVB3)-infected hearts. Adenosine monophosphate-activated protein kinase (AMPK) has been considered as a cellular fuel gauge and super metabolic regulator, however, whether AMPK has an effect on collagen production in CVB3‑infected heart remains to be elucidated. In the present study, the association between AMPK activation and CVB3‑infected neonatal rat cardiac fibroblasts (NRCFs) was investigated. Collagen production was determined by the hydroxyproline content of the supernatant and by the expression of type I/IV collagen in the cell lysate. Rat hydroxyproline ELISA was used to detect hydroxyproline content in the supernatant. The expression of type I/IV collagen, and the phosphorylation of AMPKα‑Thr172 and p38 in the cell lysate were evaluated using western blotting. As expected, it was found that the hydroxyproline content in the supernatant, and the production of collagen I/IV in the cell lysate were significantly promoted at 48 h post‑CVB3‑infection. However, this effect was inhibited in a dose‑dependent manner when pretreated with 5‑aminoimidazole‑4‑carboxamide‑1‑4‑ribofuranoside (AICAR) for 2 h prior to CVB3‑infection. However, if the cells were preincubated with compound C or SB203580 for 30 min prior the treatment with AICAR, the inhibitive effects of AICAR were reversed. The results of the western blotting indicated that the phosphorylation of AMPKα‑Thr172 and p38 were significantly increased by AICAR in the NRCFs. However, only the phosphorylation of p38 mitogen‑activated protein kinase (MAPK) was inhibited by SB203580. In conclusion, AMPK activation reduced collagen production via the p38 MAPK‑dependent pathway in the cardiac fibroblasts induced by CVB3. The results of the present study may contribute to identifying an effective therapy for CVB3‑induced myocarditis and CVB3-associated dilated cardiomyopathy.
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Affiliation(s)
- Shengyang Jiang
- Department of Cardiology, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Donglin Jiang
- Clinical Central Laboratory, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Peng Zhao
- Clinical Central Laboratory, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Xinlong He
- Clinical Central Laboratory, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Shunli Tian
- Department of Geratology, Tianjin Geriatric Institute, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Xueming Wu
- Department of Cardiology, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Yijia Tao
- Department of Cardiology, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
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17
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Behunin SM, Lopez-Pier MA, Birch CL, McKee LAK, Danilo C, Khalpey Z, Konhilas JP. LKB1/Mo25/STRAD uniquely impacts sarcomeric contractile function and posttranslational modification. Biophys J 2016; 108:1484-1494. [PMID: 25809261 DOI: 10.1016/j.bpj.2015.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 01/27/2015] [Accepted: 02/02/2015] [Indexed: 01/17/2023] Open
Abstract
The myocardium undergoes extensive metabolic and energetic remodeling during the progression of cardiac disease. Central to remodeling are changes in the adenine nucleotide pool. Fluctuations in these pools can activate AMP-activated protein kinase (AMPK), the central regulator of cellular energetics. Binding of AMP to AMPK not only allosterically activates AMPK but also promotes phosphorylation of AMPK by an upstream kinase complex, LKB1/Mo25/STRAD (liver kinase B 1, mouse protein 25, STE-related adaptor protein). AMPK phosphorylation by the LKB1 complex results in a substantial increase in AMPK activity. Molecular targeting by the LKB1 complex depends on subcellular localization and transcriptional expression. Yet, little is known about the ability of the LKB1 complex to modulate targeting of AMPK after activation. Accordingly, we hypothesized that differing stoichiometric ratios of LKB1 activator complex to AMPK would uniquely impact myofilament function. Demembranated rat cardiac trabeculae were incubated with varying ratios of the LKB1 complex to AMPK or the LKB1 complex alone. After incubation, we measured the Ca(2+) sensitivity of tension, rate constant for tension redevelopment, maximum tension generation, length-dependent activation, cooperativity, and sarcomeric protein phosphorylation status. We found that the Ca(2+) sensitivity of tension and cross-bridge dynamics were dependent on the LKB1 complex/AMPK ratio. We also found that the LKB1 complex desensitizes and suppresses myofilament function independently of AMPK. A phospho-proteomic analysis of myofilament proteins revealed site-specific changes in cardiac Troponin I (cTnI) phosphorylation, as well as a unique distribution of cTnI phosphospecies that were dependent on the LKB1 complex/ AMPK ratio. Fibers treated with the LKB1 complex alone did not alter cTnI phosphorylation or phosphospecies distribution. However, LKB1 complex treatment independent of AMPK increased phosphorylation of myosin-binding protein C. Therefore, we conclude that the LKB1/AMPK signaling axis is able to alter muscle function through multiple mechanisms.
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Affiliation(s)
- Samantha M Behunin
- Sarver Molecular Cardiovascular Research Program, Department of Physiology, University of Arizona, Tucson, Arizona
| | - Marissa A Lopez-Pier
- Sarver Molecular Cardiovascular Research Program, Department of Physiology, University of Arizona, Tucson, Arizona
| | - Camille L Birch
- Sarver Molecular Cardiovascular Research Program, Department of Physiology, University of Arizona, Tucson, Arizona
| | - Laurel A K McKee
- Sarver Molecular Cardiovascular Research Program, Department of Physiology, University of Arizona, Tucson, Arizona
| | - Christiane Danilo
- Sarver Molecular Cardiovascular Research Program, Department of Physiology, University of Arizona, Tucson, Arizona
| | - Zain Khalpey
- Department of Surgery, University of Arizona, Tucson, Arizona
| | - John P Konhilas
- Sarver Molecular Cardiovascular Research Program, Department of Physiology, University of Arizona, Tucson, Arizona.
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Jiang S, Tian S, Wu X, Tao Y, Jiang D. Effect of AMP-activated protein kinase activation on cardiac fibroblast proliferation induced by coxsackievirus B3. Exp Ther Med 2016; 11:2547-2552. [PMID: 27284347 DOI: 10.3892/etm.2016.3174] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/01/2016] [Indexed: 12/31/2022] Open
Abstract
Excessive fibroblast proliferation and collagen production are the major pathogenic mechanisms in the progression of viral myocarditis, which is most frequently associated with infection by coxsackievirus B3 (CVB3). AMP-activated protein kinase (AMPK) has been confirmed to be involved in the progression of myocardial remodeling. However, it remains unclear whether AMPK has an effect on CVB3-induced cardiac fibroblast proliferation. In the present study, the effects of AMPK on cardiac fibroblast proliferation and collagen secretion induced by CVB3 were investigated. Proliferation of neonatal cardiac fibroblasts was determined by cell counting and detection of newly synthesized DNA in cells, and the proportion of cells in the S phase was measured. Hydroxyproline ELISA was used to detect collagen secretion. Phosphorylation of AMPKα-Thr172 was evaluated by western blotting. It was found that neonatal cardiac fibroblasts were clearly proliferating markedly and secreting collagen at 24 h after CVB3 infection, and peaked at 48 h. These effects were inhibited following pretreatment of the fibroblasts with 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR), a specific AMPK activator, for 2 h prior to CVB3 infection. However, if the cells were preincubated with compound C for 30 min, the inhibitive effects of AICAR were reversed. Western blotting results indicated that AMPK α-Thr172 phosphorylation was increased by AICAR and attenuated by Compound C. The results of the present study suggest that CVB3 infection increases cardiac fibroblast proliferation and collagen secretion, and that these phenomena can be inhibited by activated AMPK. These findings contribute to our understanding of AMPK function and the future design of therapeutic approaches for the treatment of cardiac fibrosis caused by chronic viral infection, such as CVB3-induced myocarditis.
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Affiliation(s)
- Shengyang Jiang
- Department of Cardiology, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Shunli Tian
- Department of Geratology, Tianjin Geriatric Institute, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Xueming Wu
- Department of Cardiology, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Yijia Tao
- Department of Cardiology, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
| | - Donglin Jiang
- Clinical Central Laboratory, The Third Affiliated Hospital of Nantong University, Wuxi Institute of Integrated Traditional Chinese and Western Medicine, Wuxi, Jiangsu 214041, P.R. China
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19
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Activation of Adenosine Monophosphate-activated Protein Kinase Suppresses Neuroinflammation and Ameliorates Bone Cancer Pain: Involvement of Inhibition on Mitogen-activated Protein Kinase. Anesthesiology 2016; 123:1170-85. [PMID: 26378398 DOI: 10.1097/aln.0000000000000856] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Activation of adenosine monophosphate-activated kinase (AMPK) has been associated with the inhibition of inflammatory nociception and the attenuation of morphine antinociceptive tolerance. In this study, the authors investigated the impact of AMPK activation through resveratrol treatment on bone cancer pain. METHODS The nociception was assessed by measuring the incidence of foot withdrawal in response to mechanical indentation in rats (n = 8). Cytokine expression was measured using quantitative polymerase chain reaction (n = 8). Cell signalings were assayed by western blot (n = 4) and immunohistochemistry (n = 5). The microglial cell line BV-2, primary astrocytes, and neuron-like SH-SY5Y cells were cultured to investigate the in vitro effects. RESULTS Resveratrol and 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide, the AMPK activators, significantly attenuated bone cancer pain in rats with tumor cell implantation (TCI; threshold of mechanical withdrawal, resveratrol vs. vehicle: 10.1 ± 0.56 vs. 4.1 ± 0.37; 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide vs. vehicle: 8.2 ± 0.17 vs. 4.1 ± 0.37, mean ± SEM); these effects were reversed by the AMPK inhibitor compound C (compound C vs. resveratrol: 6.2 ± 1.35 vs. 10.1 ± 0.56, mean ± SEM). Resveratrol has an AMPK-dependent inhibitory effect on TCI-evoked astrocyte and microglial activation. The antinociceptive effects of resveratrol were partially mediated by the reduced phosphorylation of mitogen-activated protein kinases and decreased production of proinflammatory cytokines in an AMPK-dependent manner. Furthermore, resveratrol potently inhibited inflammatory factors-mediated protein kinase B/mammalian target of rapamycin signaling in neurons. Acute pain evoked by proinflammatory cytokines in the spinal cord was significantly attenuated by resveratrol. CONCLUSIONS AMPK activation in the spinal glia by resveratrol may have utility in the treatment of TCI-induced neuroinflammation, and our results further implicate AMPK as a novel target for the attenuation of bone cancer pain.
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20
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Yu D, Peng Y, Ayaz-Guner S, Gregorich ZR, Ge Y. Comprehensive Characterization of AMP-Activated Protein Kinase Catalytic Domain by Top-Down Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:220-32. [PMID: 26489410 PMCID: PMC4840101 DOI: 10.1007/s13361-015-1286-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/25/2015] [Accepted: 09/26/2015] [Indexed: 05/12/2023]
Abstract
AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase that is essential in regulating energy metabolism in all eukaryotic cells. It is a heterotrimeric protein complex composed of a catalytic subunit (α) and two regulatory subunits (β and γ). C-terminal truncation of AMPKα at residue 312 yielded a protein that is active upon phosphorylation of Thr172 in the absence of β and γ subunits, which is refered to as the AMPK catalytic domain and commonly used to substitute for the AMPK heterotrimeric complex in in vitro kinase assays. However, a comprehensive characterization of the AMPK catalytic domain is lacking. Herein, we expressed a His-tagged human AMPK catalytic domin (denoted as AMPKΔ) in E. coli, comprehensively characterized AMPKΔ in its basal state and after in vitro phosphorylation using top-down mass spectrometry (MS), and assessed how phosphorylation of AMPKΔ affects its activity. Unexpectedly, we found that bacterially-expressed AMPKΔ was basally phosphorylated and localized the phosphorylation site to the His-tag. We found that AMPKΔ had noticeable basal activity and was capable of phosphorylating itself and its substrates without activating phosphorylation at Thr172. Moreover, our data suggested that Thr172 is the only site phosphorylated by its upstream kinase, liver kinase B1, and that this phosphorylation dramatically increases the kinase activity of AMPKΔ. Importantly, we demonstrated that top-down MS in conjunction with in vitro phosphorylation assay is a powerful approach for monitoring phosphorylation reaction and determining sequential order of phosphorylation events in kinase-substrate systems.
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Affiliation(s)
- Deyang Yu
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Molecular and Environmental Toxicology Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Ying Peng
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Serife Ayaz-Guner
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Zachery R. Gregorich
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Ying Ge
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Molecular and Environmental Toxicology Training Program, University of Wisconsin-Madison, Madison, WI, USA
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Address reprint requests to: Dr. Ying Ge, 1300 University Ave., SMI 130, Madison, Wisconsin, USA. Tel: 608-263-9212, Fax: 608-265-5512,
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21
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Oestrogen receptors interact with the α-catalytic subunit of AMP-activated protein kinase. Biosci Rep 2015; 35:BSR20150074. [PMID: 26374855 PMCID: PMC4626870 DOI: 10.1042/bsr20150074] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 09/10/2015] [Indexed: 01/19/2023] Open
Abstract
We identified a novel interaction between the classical oestrogen receptors (ERα and ERβ) and the catalytic subunit of AMP-activated protein kinase (AMPK) in several cell types. In addition, we demonstrate that oestradiol (E2) activates AMPK through ERα and requires the upstream kinase complex liver kinase B (LKB1). Normal and pathological stressors engage the AMP-activated protein kinase (AMPK) signalling axis to protect the cell from energetic pressures. Sex steroid hormones also play a critical role in energy metabolism and significantly modify pathological progression of cardiac disease, diabetes/obesity and cancer. AMPK is targeted by 17β-oestradiol (E2), the main circulating oestrogen, but the mechanism by which E2 activates AMPK is currently unknown. Using an oestrogen receptor α/β (ERα/β) positive (T47D) breast cancer cell line, we validated E2-dependent activation of AMPK that was mediated through ERα (not ERβ) by using three experimental strategies. A series of co-immunoprecipitation experiments showed that both ERs associated with AMPK in cancer and striated (skeletal and cardiac) muscle cells. We further demonstrated direct binding of ERs to the α-catalytic subunit of AMPK within the βγ-subunit-binding domain. Finally, both ERs interacted with the upstream liver kinase B 1 (LKB1) kinase complex, which is required for E2-dependent activation of AMPK. We conclude that E2 activates AMPK through ERα by direct interaction with the βγ-binding domain of AMPKα.
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Abstract
The heart is a very special organ in the body and has a high requirement for metabolism due to its constant workload. As a consequence, to provide a consistent and sufficient energy a high steady-state demand of metabolism is required by the heart. When delicately balanced mechanisms are changed by physiological or pathophysiological conditions, the whole system's homeostasis will be altered to a new balance, which contributes to the pathologic process. So it is no wonder that almost every heart disease is related to metabolic shift. Furthermore, aging is also found to be related to the reduction in mitochondrial function, insulin resistance, and dysregulated intracellular lipid metabolism. Adenosine monophosphate-activated protein kinase (AMPK) functions as an energy sensor to detect intracellular ATP/AMP ratio and plays a pivotal role in intracellular adaptation to energy stress. During different pathology (like myocardial ischemia and hypertension), the activation of cardiac AMPK appears to be essential for repairing cardiomyocyte's function by accelerating ATP generation, attenuating ATP depletion, and protecting the myocardium against cardiac dysfunction and apoptosis. In this overview, we will talk about the normal heart's metabolism, how metabolic shifts during aging and different pathologies, and how AMPK regulates metabolic changes during these conditions.
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Affiliation(s)
- Yina Ma
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, NY 14214
| | - Ji Li
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, NY 14214
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23
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Rybakowska IM, Slominska EM, Romaszko P, Olkowicz M, Kaletha K, Smolenski RT. AMP-regulated protein kinase activity in the hearts of mice treated with low- or high-fat diet measured using novel LC-MS method. Mol Cell Biochem 2015; 404:5-10. [PMID: 25711403 PMCID: PMC4544673 DOI: 10.1007/s11010-015-2360-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/14/2015] [Indexed: 11/25/2022]
Abstract
AMP-regulated protein kinase (AMPK) is involved in regulation of energy-generating pathways in response to the metabolic needs in different organs including the heart. The activity of AMPK is mainly controlled by AMP concentration that in turn could be affected by nucleotide metabolic pathways. This study aimed to develop a procedure for measurement of AMPK activity together with nucleotide metabolic enzymes and its application for studies of mice treated with high-fat diet. The method developed was based on analysis of conversion of AMARA peptide to pAMARA by partially purified heart homogenate by liquid chromatography/mass spectrometry (LC/MS). Activities of the enzymes of nucleotide metabolism were evaluated by analysis of conversion of substrates into products by HPLC. The method was applied for analysis of hearts of mice fed 12 weeks with low- (LFD) or high-fat diet (HFD). The optimized method for AMPK activity analysis (measured in presence of AMP) revealed change of activity from 0.089 ± 0.035 pmol/min/mg protein in LFD to 0.024 ± 0.002 in HFD. This coincided with increase of adenosine deaminase (ADA) activity from 0.11 ± 0.02 to 0.19 ± 0.06 nmol/mg tissue/min and decrease of AMP-deaminase (AMPD) activity from 1.26 ± 0.35 to 0.56 ± 0.15 nmol/mg tissue/min for LFD and HFD, respectively. We have proven quality of our LC/MS method for analysis of AMPK activity. We observed decrease in AMPK activity in the heart of mice treated with high-fat diet. However, physiological consequences of this change could be modulated by decrease in AMPD activity.
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Affiliation(s)
- I M Rybakowska
- Department of Biochemistry and Clinical Physiology, Medical University of Gdansk, Debinki 1, 80-211, Gdańsk, Poland,
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Morrison A, Chen L, Wang J, Zhang M, Yang H, Ma Y, Budanov A, Lee JH, Karin M, Li J. Sestrin2 promotes LKB1-mediated AMPK activation in the ischemic heart. FASEB J 2015; 29:408-17. [PMID: 25366347 PMCID: PMC4314228 DOI: 10.1096/fj.14-258814] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/19/2014] [Indexed: 11/11/2022]
Abstract
The regulation of AMPK in the ischemic heart remains incompletely understood. Recent evidence implicates the role of Sestrin2 in the AMPK signaling pathway, and it is hypothesized that Sestrin2 plays an influential role during myocardial ischemia to promote AMPK activation. Sestrin2 protein was found to be expressed in adult cardiomyocytes and accumulated in the heart during ischemic conditions. Sestrin2 knockout (KO) mice were used to determine the importance of Sestrin2 during ischemia and reperfusion (I/R) injury. When wild-type (WT) and Sestrin2 KO mice were subjected to in vivo I/R, myocardial infarct size was significantly greater in Sestrin2 KO compared with WT hearts. Similarly, Langendorff perfused hearts indicated exacerbated postischemic contractile function in Sestrin2 KO hearts compared with WT. Ischemic AMPK activation was found to be impaired in the Sestrin2 KO hearts. Immunoprecipitation of Sestrin2 demonstrated an association with AMPK. Moreover, liver kinase B1 (LKB1), a major AMPK upstream kinase, was associated with the Sestrin2-AMPK complex in a time-dependent manner during ischemia, whereas this interaction was nearly abolished in Sestrin2 KO hearts. Thus, Sestrin2 plays an important role in cardioprotection against I/R injury, serving as an LKB1-AMPK scaffold to initiate AMPK activation during ischemic insults.
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Affiliation(s)
- Alex Morrison
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York, USA
| | - Li Chen
- Department of Pharmacology, College of Basic Medicine, Jilin University, Changchun, Jilin, China
| | - Jinli Wang
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York, USA
| | - Ming Zhang
- Department of Pharmacology, College of Basic Medicine, Jilin University, Changchun, Jilin, China
| | - Hui Yang
- Department of Pathology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yina Ma
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York, USA
| | - Andrei Budanov
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Jun Hee Lee
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA; and
| | - Michael Karin
- Department of Pharmacology, University of California at San Diego, La Jolla, California, USA
| | - Ji Li
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York, USA;
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Khatri N, Man HY. Synaptic activity and bioenergy homeostasis: implications in brain trauma and neurodegenerative diseases. Front Neurol 2013; 4:199. [PMID: 24376435 PMCID: PMC3858785 DOI: 10.3389/fneur.2013.00199] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/26/2013] [Indexed: 12/14/2022] Open
Abstract
Powered by glucose metabolism, the brain is the most energy-demanding organ in our body. Adequate ATP production and regulation of the metabolic processes are essential for the maintenance of synaptic transmission and neuronal function. Glutamatergic synaptic activity utilizes the largest portion of bioenergy for synaptic events including neurotransmitter synthesis, vesicle recycling, and most importantly, the postsynaptic activities leading to channel activation and rebalancing of ionic gradients. Bioenergy homeostasis is coupled with synaptic function via activities of the sodium pumps, glutamate transporters, glucose transport, and mitochondria translocation. Energy insufficiency is sensed by the AMP-activated protein kinase (AMPK), a master metabolic regulator that stimulates the catalytic process to enhance energy production. A decline in energy supply and a disruption in bioenergy homeostasis play a critical role in multiple neuropathological conditions including ischemia, stroke, and neurodegenerative diseases including Alzheimer’s disease and traumatic brain injuries.
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Affiliation(s)
- Natasha Khatri
- Department of Biology, Boston University , Boston, MA , USA ; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine , Boston, MA , USA
| | - Heng-Ye Man
- Department of Biology, Boston University , Boston, MA , USA ; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine , Boston, MA , USA
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26
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Turkseven S, Ertuna E. Prolonged AMP-activated protein kinase induction impairs vascular functions. Can J Physiol Pharmacol 2013; 91:1025-30. [DOI: 10.1139/cjpp-2013-0160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AMP-activated protein kinase (AMPK) is a regulator of cellular metabolism and is involved in the pathogenesis of several diseases, including type 2 diabetes and cardiovascular diseases. Data showing the effects of AMPK on vasculature are controversial. Therefore, the aim of this study was to determine the impact of prolonged AMPK activation on vascular functions. For this purpose we have examined the role of AMPK in endothelium-dependent and -independent relaxation and vascular contractions. For this, we incubated thoracic aortic rings, from rats, with AMPK activator 5-aminoimidazole-4-carboxamide-1-4-ribofuranoside (AICAR, 500 μmol/L or 2 mmol/L) in the presence or absence of AMPK inhibitor compound C (10 μmol/L). Next, cumulative dose–response curves to acetylcholine (ACh) (10−9−10−4 mol/L), nitroglycerine (NG) (10−9–3 × 10−5 mol/L), and noradrenaline (NA) (10−9−10−4 mol/L) were obtained. Endothelial nitric oxide synthase (eNOS) protein expression was determined. Our results show that endothelium-dependent relaxation was inhibited after AICAR treatment, and that this effect was reversed by AMPK inhibition. Moreover, AICAR enhanced the contractile response to NA and caused a decrease in eNOS protein expression. In conclusion, prolonged AMPK induction causes endothelial impairment, possibly via increased degradation and (or) reduced expression of eNOS.
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Affiliation(s)
- Saadet Turkseven
- Ege University, Faculty of Pharmacy, Department of Pharmacology, Bornova-Izmir 35100, Turkey
| | - Elif Ertuna
- Ege University, Faculty of Pharmacy, Department of Pharmacology, Bornova-Izmir 35100, Turkey
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Jiang S, Park DW, Stigler WS, Creighton J, Ravi S, Darley-Usmar V, Zmijewski JW. Mitochondria and AMP-activated protein kinase-dependent mechanism of efferocytosis. J Biol Chem 2013; 288:26013-26026. [PMID: 23897815 DOI: 10.1074/jbc.m113.489468] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Defective clearance of apoptotic cells is frequently associated with perpetuation of inflammatory conditions. Our results show a rapid activation of AMP-activated kinase (AMPK) in macrophages upon exposure to apoptotic cells or lysophosphatidylcholine, a specific phospholipid that is produced and released from dying cells. AMPK activation resulted from inhibition of mitochondrial oxygen consumption and ATP production and further depended on Ca(2+) mobilization and mitochondrial reactive oxygen species generation. Once activated, AMPK increased microtubule synthesis and chemokinesis and provided adaptation to energy demand during tracking and engulfment. Uptake of apoptotic cells was increased in lungs of mice that received lysophosphatidylcholine. Furthermore, inhibition of AMPK diminished clearance of apoptotic thymocytes in vitro and in dexamethasone-treated mice. Taken together, we conclude that the mitochondrial AMPK axis is a sensor and enhancer of tracking and removal of apoptotic cell, processes crucial to resolution of inflammatory conditions and a return to tissue homeostasis.
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Affiliation(s)
| | - Dae Won Park
- From the Department of Medicine,; the Division of Infectious Diseases, Korea University Ansan Hospital, Ansan 425-707, Republic of Korea
| | | | | | | | - Victor Darley-Usmar
- Department of Pathology, and; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0012 and
| | - Jaroslaw W Zmijewski
- From the Department of Medicine,; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0012 and.
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28
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Huke S, Venkataraman R, Faggioni M, Bennuri S, Hwang HS, Baudenbacher F, Knollmann BC. Focal energy deprivation underlies arrhythmia susceptibility in mice with calcium-sensitized myofilaments. Circ Res 2013; 112:1334-44. [PMID: 23532597 DOI: 10.1161/circresaha.113.301055] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
RATIONALE The Ca(2+) sensitivity of the myofilaments is increased in hypertrophic cardiomyopathy and other heart diseases and may contribute to a higher risk for sudden cardiac death. Ca(2+) sensitization increases susceptibility to reentrant ventricular tachycardia in animal models, but the underlying mechanism is unknown. OBJECTIVE To investigate how myofilament Ca(2+) sensitization creates reentrant arrhythmia susceptibility. METHODS AND RESULTS Using hypertrophic cardiomyopathy mouse models (troponinT-I79N) and a Ca(2+) sensitizing drug (EMD57033), here we identify focal energy deprivation as a direct consequence of myofilament Ca(2+) sensitization. To detect ATP depletion and thus energy deprivation, we measured accumulation of dephosphorylated Connexin 43 (Cx43) isoform P0 and AMP kinase activation by Western blotting and immunostaining. No differences were detected between groups at baseline, but regional accumulation of Connexin 43 isoform P0 occurred within minutes in all Ca(2+)-sensitized hearts, in vivo after isoproterenol challenge and in isolated hearts after rapid pacing. Lucifer yellow dye spread demonstrated reduced gap junctional coupling in areas with Connexin 43 isoform P0 accumulation. Optical mapping revealed that selectively the transverse conduction velocity was slowed and anisotropy increased. Myofilament Ca(2+) desensitization with blebbistatin prevented focal energy deprivation, transverse conduction velocity slowing, and the reentrant ventricular arrhythmias. CONCLUSIONS Myofilament Ca(2+) sensitization rapidly leads to focal energy deprivation and reduced intercellular coupling during conditions that raise arrhythmia susceptibility. This is a novel proarrhythmic mechanism that can increase arrhythmia susceptibility in structurally normal hearts within minutes and may, therefore, contribute to sudden cardiac death in diseases with increased myofilament Ca(2+) sensitivity.
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Affiliation(s)
- Sabine Huke
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA.
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29
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Yan H, Zhang DX, Shi X, Zhang Q, Huang YS. Activation of the prolyl-hydroxylase oxygen-sensing signal cascade leads to AMPK activation in cardiomyocytes. J Cell Mol Med 2013; 16:2049-59. [PMID: 22128786 PMCID: PMC3822975 DOI: 10.1111/j.1582-4934.2011.01500.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The proline hydroxylase domain-containing enzymes (PHD) act as cellular oxygen sensors and initiate a hypoxic signal cascade to induce a range of cellular responses to hypoxia especially in the aspect of energy and metabolic homeostasis regulation. AMP-activated protein kinase (AMPK) is recognized as a major energetic sensor and regulator of cardiac metabolism. However, the effect of PHD signal on AMPK has never been studied before. A PHD inhibitor (PHI), dimethyloxalylglycine and PHD2-specific RNA interference (RNAi) have been used to activate PHD signalling in neonatal rat cardiomyocytes. Both PHI and PHD2-RNAi activated AMPK pathway in cardiomyocytes effectively. In addition, the increased glucose uptake during normoxia and enhanced myocyte viability during hypoxia induced by PHI pretreatment were abrogated substantially upon AMPK inhibition with an adenoviral vector expressing a dominant negative mutant of AMPK-α1. Furthermore, chelation of intracellular Ca2+ by BAPTA, inhibition of calmodulin-dependent kinase kinase (CaMKK) with STO-609, or RNAi-mediated down-regulation of CaMKK α inhibited PHI-induced AMPK activation significantly. In contrast, down-regulation of LKB1 with adenoviruses expressing the dominant negative form did not affect PHI-induced AMPK activation. We establish for the first time that activation of PHD signal cascade can activate AMPK pathway mainly through a Ca(2+)/CaMKK-dependent mechanism in cardiomyocytes. Furthermore, activation of AMPK plays an essential role in hypoxic protective responses induced by PHI.
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Affiliation(s)
- Hong Yan
- Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns and Combined Injury, The Third Military Medical University, Chongqing, China
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30
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Abstract
AMP-activated protein kinase (AMPK) is a stress-activated kinase that functions as a cellular fuel gauge and master metabolic regulator. Recent investigation has elucidated novel molecular mechanisms of AMPK regulation and important biological actions of the AMPK pathway that are highly relevant to cardiovascular disease. Activation of the intrinsic AMPK pathway plays an important role in the myocardial response to ischemia, pressure overload, and heart failure. Pharmacological activation of AMPK shows promise as a therapeutic strategy in the treatment of heart disease. The purpose of this review is to assess how recent discoveries have extended and in some cases challenged existing paradigms, providing new insights into the regulation of AMPK, its diverse biological actions, and therapeutic potential in the heart.
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Affiliation(s)
- Vlad G Zaha
- Department of Internal Medicine, Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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31
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Abstract
There has been considerable progress in our understanding of cardiac cell metabolism in health and disease, yet important gaps remain in basic knowledge and its translation to clinical care. AMP-activated protein kinase (AMPK) functions either to conserve ATP or to promote alternative methods of ATP generation. Since the discovery of AMPK more than three decades ago and demonstration of its expression in the heart, interest has grown exponentially in this major fuel gauge as a modulator of the cellular response to ischemia. Such pathway may potentially explain the strong association between metabolic syndrome and ischemic heart disease. Still missing from our most recent cardiology textbooks, this article aims to summarize our understanding so far of the role of AMPK in coordinating the cellular response to ischemic stress and reperfusion injury in the heart. We aim to provide a focused update on the pharmacological agents activating AMPK for treatment of diabetes that show potential cardioprotective effects. Our hope is to stimulate future researchers to the potential benefits of harnessing the AMPK signaling pathway, or better one of its novel downstream targets for the treatment of myocardial ischemia.
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32
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The role of PPARα in metformin-induced attenuation of mitochondrial dysfunction in acute cardiac ischemia/reperfusion in rats. Int J Mol Sci 2012; 13:7694-7709. [PMID: 22837722 PMCID: PMC3397554 DOI: 10.3390/ijms13067694] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 05/31/2012] [Accepted: 06/18/2012] [Indexed: 12/25/2022] Open
Abstract
Metformin, an anti-diabetic drug, exerts cardioprotection against ischemia-reperfusion (IR) through the activation of AMPK. However, the molecular mechanisms underlying these beneficial effects remain elusive. In this study, we examined the role of PPARα in mediating cardioprotective effects of metformin on mitochondria. Hearts of male Sprague-Dawley rats perfused by Langendorff were subjected to IR in the presence or absence of metformin and the PPARβ inhibitor, GW6471. IR reduced cardiac function and compromised the structural integrity of cardiac cells evidenced by increased LDH release from the hearts. In addition, IR induced mitochondrial dysfunction as evidenced by reduced respiration and increased mitochondrial permeability transition pore (PTP) opening. However, metformin-treated hearts demonstrated improved post-ischemic recovery of cardiac function and reduced cell death that were associated with increased state 3 respiration at complexes I and II (by 27% and 32%, respectively, both p < 0.05) and decreased PTP opening (by 27%, p < 0.05) compared to untreated hearts. The protective effects of metformin on cardiac function and mitochondria were blocked by GW6471. Thus, our results demonstrate that inhibition of PPARα attenuates the beneficial effects of metformin on mitochondria in acute IR.
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Hurtado de Llera A, Martin-Hidalgo D, Gil MC, Garcia-Marin LJ, Bragado MJ. AMP-activated kinase AMPK is expressed in boar spermatozoa and regulates motility. PLoS One 2012; 7:e38840. [PMID: 22719961 PMCID: PMC3375287 DOI: 10.1371/journal.pone.0038840] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 05/11/2012] [Indexed: 01/23/2023] Open
Abstract
The main functions of spermatozoa required for fertilization are dependent on the energy status and metabolism. AMP-activated kinase, AMPK, acts a sensor and regulator of cell metabolism. As AMPK studies have been focused on somatic cells, our aim was to investigate the expression of AMPK protein in spermatozoa and its possible role in regulating motility. Spermatozoa from boar ejaculates were isolated and incubated under different conditions (38,5°C or 17°C, basal medium TBM or medium with Ca(2+) and bicarbonate TCM, time from 1-24 hours) in presence or absence of AMPK inhibitor, compound C (CC, 30 µM). Western blotting reveals that AMPK is expressed in boar spermatozoa at relatively higher levels than in somatic cells. AMPK phosphorylation (activation) in spermatozoa is temperature-dependent, as it is undetectable at semen preservation temperature (17°C) and increases at 38,5°C in a time-dependent manner. AMPK phosphorylation is independent of the presence of Ca(2+) and/or bicarbonate in the medium. We confirm that CC effectively blocks AMPK phosphorylation in boar spermatozoa. Analysis of spermatozoa motility by CASA shows that CC treatment either in TBM or in TCM causes a significant reduction of any spermatozoa motility parameter in a time-dependent manner. Thus, AMPK inhibition significantly decreases the percentages of motile and rapid spermatozoa, significantly reduces spermatozoa velocities VAP, VCL and affects other motility parameters and coefficients. CC treatment does not cause additional side effects in spermatozoa that might lead to a lower viability even at 24 h incubation. Our results show that AMPK is expressed in spermatozoa at high levels and is phosphorylated under physiological conditions. Moreover, our study suggests that AMPK regulates a relevant function of spermatozoa, motility, which is essential for their ultimate role of fertilization.
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Affiliation(s)
- Ana Hurtado de Llera
- Research Group of Intracellular Signalling and Technology of Reproduction (SINTREP), Veterinary School, University of Extremadura, Caceres, Spain
| | - David Martin-Hidalgo
- Research Group of Intracellular Signalling and Technology of Reproduction (SINTREP), Veterinary School, University of Extremadura, Caceres, Spain
| | - María C. Gil
- Research Group of Intracellular Signalling and Technology of Reproduction (SINTREP), Veterinary School, University of Extremadura, Caceres, Spain
| | - Luis J. Garcia-Marin
- Research Group of Intracellular Signalling and Technology of Reproduction (SINTREP), Veterinary School, University of Extremadura, Caceres, Spain
| | - María J. Bragado
- Research Group of Intracellular Signalling and Technology of Reproduction (SINTREP), Veterinary School, University of Extremadura, Caceres, Spain
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34
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Tadie JM, Bae HB, Deshane JS, Bell CP, Lazarowski ER, Chaplin DD, Thannickal VJ, Abraham E, Zmijewski JW. Toll-like receptor 4 engagement inhibits adenosine 5'-monophosphate-activated protein kinase activation through a high mobility group box 1 protein-dependent mechanism. Mol Med 2012; 18:659-68. [PMID: 22396017 DOI: 10.2119/molmed.2011.00401] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 03/01/2012] [Indexed: 12/29/2022] Open
Abstract
Despite the potent antiinflammatory effects of pharmacologically induced adenosine 5'-monophosphate kinase (AMPK) activation on Toll-like receptor 4 (TLR4)-induced cellular activation, there is little evidence that AMPK is activated during inflammatory conditions. In the present studies, we examined mechanisms by which TLR4 engagement may affect the ability of AMPK to become activated in neutrophils and macrophages under in vitro conditions and in the lungs during lipopolysaccharide (LPS)-induced acute lung injury. We found that incubation of neutrophils or macrophages with LPS diminished the ability of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) or hydrogen peroxide (H(2)O(2)) to activate AMPK. Although ratios of AMP to adenosine 5'-triphosphate (ATP) were increased in LPS-treated neutrophils and in the lungs of LPS exposed mice, a condition that should result in AMPK activation, no activation of AMPK was found. Immunocytochemistry and Western blot analysis revealed that nuclear to cytosolic translocation of the proinflammatory mediator high mobility group box 1 protein (HMGB1) correlated with inhibition of AMPK activation in LPS-stimulated macrophages. Moreover, while induced overexpression of HMGB1 resulted in inhibition of AMPK activation, Small interfering RNA (siRNA)-induced knockdown of HMGB1 was associated with enhanced activation of AMPK in macrophages incubated with AICAR. Increased interaction between liver kinase B1 (LKB1), an upstream activator of AMPK, and HMGB1 was found in LPS-stimulated macrophages and in the lungs of mice exposed to LPS. These results suggest that nuclear to cytoplasmic translocation of HMGB1 in TLR4-activated cells potentiates inflammatory responses by binding to LKB1, thereby inhibiting the antiinflammatory effects of AMPK activation.
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Affiliation(s)
- Jean-Marc Tadie
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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35
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Song P, Zou MH. Regulation of NAD(P)H oxidases by AMPK in cardiovascular systems. Free Radic Biol Med 2012; 52:1607-19. [PMID: 22357101 PMCID: PMC3341493 DOI: 10.1016/j.freeradbiomed.2012.01.025] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are ubiquitously produced in cardiovascular systems. Under physiological conditions, ROS/RNS function as signaling molecules that are essential in maintaining cardiovascular function. Aberrant concentrations of ROS/RNS have been demonstrated in cardiovascular diseases owing to increased production or decreased scavenging, which have been considered common pathways for the initiation and progression of cardiovascular diseases such as atherosclerosis, hypertension, (re)stenosis, and congestive heart failure. NAD(P)H oxidases are primary sources of ROS and can be induced or activated by all known cardiovascular risk factors. Stresses, hormones, vasoactive agents, and cytokines via different signaling cascades control the expression and activity of these enzymes and of their regulatory subunits. But the molecular mechanisms by which NAD(P)H oxidase is regulated in cardiovascular systems remain poorly characterized. Investigations by us and others suggest that adenosine monophosphate-activated protein kinase (AMPK), as an energy sensor and modulator, is highly sensitive to ROS/RNS. We have also obtained convincing evidence that AMPK is a physiological suppressor of NAD(P)H oxidase in multiple cardiovascular cell systems. In this review, we summarize our current understanding of how AMPK functions as a physiological repressor of NAD(P)H oxidase.
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Affiliation(s)
| | - Ming-Hui Zou
- To whom correspondence should be addressed: Ming-Hui Zou, M.D., Ph.D., Department of Medicine, University of Oklahoma Health Science Center, 941 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA, Phone: 405-271-3974, Fax: 405-271-3973,
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36
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Yoshida H, Bao L, Kefaloyianni E, Taskin E, Okorie U, Hong M, Dhar-Chowdhury P, Kaneko M, Coetzee WA. AMP-activated protein kinase connects cellular energy metabolism to KATP channel function. J Mol Cell Cardiol 2011; 52:410-8. [PMID: 21888913 DOI: 10.1016/j.yjmcc.2011.08.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 06/21/2011] [Accepted: 08/17/2011] [Indexed: 11/29/2022]
Abstract
AMPK is an important sensor of cellular energy levels. The aim of these studies was to investigate whether cardiac K(ATP) channels, which couple cellular energy metabolism to membrane excitability, are regulated by AMPK activity. We investigated effects of AMPK on rat ventricular K(ATP) channels using electrophysiological and biochemical approaches. Whole-cell K(ATP) channel current was activated by metabolic inhibition; this occurred more rapidly in the presence of AICAR (an AMPK activator). AICAR had no effects on K(ATP) channel activity recorded in the inside-out patch clamp configuration, but ZMP (the intracellular intermediate of AICAR) strongly activated K(ATP) channels. An AMPK-mediated effect is demonstrated by the finding that ZMP had no effect on K(ATP) channels in the presence of Compound C (an AMPK inhibitor). Recombinant AMPK activated Kir6.2/SUR2A channels in a manner that was dependent on the AMP concentration, whereas heat-inactivated AMPK was without effect. Using mass-spectrometry and co-immunoprecipitation approaches, we demonstrate that the AMPK α-subunit physically associates with K(ATP) channel subunits. Our data demonstrate that the cardiac K(ATP) channel function is directly regulated by AMPK activation. During metabolic stress, a small change in cellular AMP that activates AMPK can be a potential trigger for K(ATP) channel opening. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
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Affiliation(s)
- Hidetada Yoshida
- Pediatric Cardiology, NYU School of Medicine, New York, NY 10016, USA
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Heidrich F, Schotola H, Popov AF, Sohns C, Schuenemann J, Friedrich M, Coskun KO, von Lewinski D, Hinz J, Bauer M, Mokashi SA, Sossalla S, Schmitto JD. AMPK - Activated Protein Kinase and its Role in Energy Metabolism of the Heart. Curr Cardiol Rev 2010; 6:337-42. [PMID: 22043210 PMCID: PMC3083815 DOI: 10.2174/157340310793566073] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 04/30/2010] [Accepted: 05/01/2010] [Indexed: 11/22/2022] Open
Abstract
Adenosine monophosphate - activated kinase (AMPK) plays a key role in the coordination of the heart's anabolic and catabolic pathways. It induces a cellular cascade at the center of maintaining energy homeostasis in the cardiomyocytes.. The activated AMPK is a heterotrimeric protein, separated into a catalytic α - subunit (63kDa), a regulating β - subunit (38kDa) and a γ - subunit (38kDa), which is allosterically adjusted by adenosine triphosphate (ATP) and adenosine monophosphate (AMP). The actual binding of AMP to the γ - subunit is the step which activates AMPK. AMPK serves also as a protein kinase in several metabolic pathways of the heart, including cellular energy sensoring or cardiovascular protection. The AMPK cascade represents a sensitive system, activated by cellular stresses that deplete ATP and acts as an indicator of intracellular ATP/AMP. In the context of cellular stressors (i.e. hypoxia, pressure overload, hypertrophy or ATP deficiency) the increasing levels of AMP promote allosteric activation and phosphorylation of AMPK. As the concentration of AMP begins to increase, ATP competitively inhibits further phosphorylation of AMPK. The increase of AMP may also be induced either from an iatrogenic emboli, percutaneous coronary intervention, or from atherosclerotic plaque rupture leading to an ischemia in the microcirculation. To modulate energy metabolism by phosphorylation and dephosphorylation is vital in terms of ATP usage, maintaining transmembrane transporters and preserving membrane potential. In this article, we review AMPK and its role as an important regulatory enzyme during periods of myocardial stress, regulating energy metabolism, protein synthesis and cardiovascular protection.
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Affiliation(s)
- Florian Heidrich
- Department of Thoracic, Cardiac and Vascular Surgery, University of Goettingen, Goettingen, Germany
| | - Hanna Schotola
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Goettingen, Goettingen, Germany
| | - Aron F Popov
- Department of Thoracic, Cardiac and Vascular Surgery, University of Goettingen, Goettingen, Germany
| | - Christian Sohns
- Department of Cardiology, University of Goettingen, Goettingen, Germany
| | - Julia Schuenemann
- Department of Thoracic, Cardiac and Vascular Surgery, University of Goettingen, Goettingen, Germany
| | - Martin Friedrich
- Department of Thoracic, Cardiac and Vascular Surgery, University of Goettingen, Goettingen, Germany
| | - Kasim O Coskun
- Department of Thoracic, Cardiac and Vascular Surgery, University of Goettingen, Goettingen, Germany
| | | | - Jose Hinz
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Goettingen, Goettingen, Germany
| | - Martin Bauer
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Goettingen, Goettingen, Germany
| | - Suyog A Mokashi
- Division of Cardiac Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Samuel Sossalla
- Department of Cardiology, University of Goettingen, Goettingen, Germany
| | - Jan D Schmitto
- Department of Thoracic, Cardiac and Vascular Surgery, University of Goettingen, Goettingen, Germany
- Division of Cardiac Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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Abstract
AbstractAdenosine Monophosphate-activated Protein Kinase (AMPK), a serine/threonine kinase and a member of the Snf1/AMPK protein kinase family, consists of three protein subunits that together make a functional enzyme. AMPK, which is expressed in a number of tissues, including the liver, brain, and skeletal muscle, is allosterically activated by a rise in the AMP: ATP ratio (ie in a low ATP or energy depleted state). The net effect of AMPK activation is to halt energy consuming (anabolic) pathways but to promote energy conserving (catabolic) cellular pathways. AMPK has therefore often been dubbed the "metabolic master switch". AMPK also plays a critical physiological role in the cardiovascular system. Increasing evidence suggest that AMPK might also function as a sensor by responding to oxidative stress. Mostly importantly, AMPK modulates endogenous antioxidant gene expression and/or suppress the production of oxidants. AMPK promotes cardiovascular homeostasis by ensuring an optimum redox balance on the heart and vascular tissues. Dysfunctional AMPK is thought to underlie several cardiovascular pathologies. Here we review this kinase from its structure and discovery to current knowledge of its adaptive and maladaptive role in the cardiovascular system.
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Zmijewski JW, Banerjee S, Bae H, Friggeri A, Lazarowski ER, Abraham E. Exposure to hydrogen peroxide induces oxidation and activation of AMP-activated protein kinase. J Biol Chem 2010; 285:33154-33164. [PMID: 20729205 DOI: 10.1074/jbc.m110.143685] [Citation(s) in RCA: 295] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Although metabolic conditions associated with an increased AMP/ATP ratio are primary factors in the activation of 5'-adenosine monophosphate-activated protein kinase (AMPK), a number of recent studies have shown that increased intracellular levels of reactive oxygen species can stimulate AMPK activity, even without a decrease in cellular levels of ATP. We found that exposure of recombinant AMPKαβγ complex or HEK 293 cells to H(2)O(2) was associated with increased kinase activity and also resulted in oxidative modification of AMPK, including S-glutathionylation of the AMPKα and AMPKβ subunits. In experiments using C-terminal truncation mutants of AMPKα (amino acids 1-312), we found that mutation of cysteine 299 to alanine diminished the ability of H(2)O(2) to induce kinase activation, and mutation of cysteine 304 to alanine totally abrogated the enhancing effect of H(2)O(2) on kinase activity. Similar to the results obtained with H(2)O(2)-treated HEK 293 cells, activation and S-glutathionylation of the AMPKα subunit were present in the lungs of acatalasemic mice or mice treated with the catalase inhibitor aminotriazole, conditions in which intracellular steady state levels of H(2)O(2) are increased. These results demonstrate that physiologically relevant concentrations of H(2)O(2) can activate AMPK through oxidative modification of the AMPKα subunit. The present findings also imply that AMPK activation, in addition to being a response to alterations in intracellular metabolic pathways, is directly influenced by cellular redox status.
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Affiliation(s)
- Jaroslaw W Zmijewski
- From the Department of Medicine, Birmingham, Alabama 35294-0012; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0012.
| | - Sami Banerjee
- From the Department of Medicine, Birmingham, Alabama 35294-0012
| | - Hongbeom Bae
- From the Department of Medicine, Birmingham, Alabama 35294-0012; Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju 501-746, Republic of Korea
| | - Arnaud Friggeri
- From the Department of Medicine, Birmingham, Alabama 35294-0012
| | - Eduardo R Lazarowski
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248
| | - Edward Abraham
- From the Department of Medicine, Birmingham, Alabama 35294-0012; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0012.
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40
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Ren J, Pulakat L, Whaley-Connell A, Sowers JR. Mitochondrial biogenesis in the metabolic syndrome and cardiovascular disease. J Mol Med (Berl) 2010; 88:993-1001. [PMID: 20725711 DOI: 10.1007/s00109-010-0663-9] [Citation(s) in RCA: 263] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 07/26/2010] [Accepted: 07/28/2010] [Indexed: 12/23/2022]
Abstract
The metabolic syndrome is a constellation of metabolic disorders including obesity, hypertension, and insulin resistance, components which are risk factors for the development of diabetes, hypertension, cardiovascular, and renal disease. Pathophysiological abnormalities that contribute to the development of the metabolic syndrome include impaired mitochondrial oxidative phosphorylation and mitochondrial biogenesis, dampened insulin metabolic signaling, endothelial dysfunction, and associated myocardial functional abnormalities. Recent evidence suggests that impaired myocardial mitochondrial biogenesis, fatty acid metabolism, and antioxidant defense mechanisms lead to diminished cardiac substrate flexibility, decreased cardiac energetic efficiency, and diastolic dysfunction. In addition, enhanced activation of the renin-angiotensin-aldosterone system and associated increases in oxidative stress can lead to mitochondrial apoptosis and degradation, altered bioenergetics, and accumulation of lipids in the heart. In addition to impairments in metabolic signaling and oxidative stress, genetic and environmental factors, aging, and hyperglycemia all contribute to reduced mitochondrial biogenesis and mitochondrial dysfunction. These mitochondrial abnormalities can predispose a metabolic cardiomyopathy characterized by diastolic dysfunction. Mitochondrial dysfunction and resulting lipid accumulation in skeletal muscle, liver, and pancreas also impede insulin metabolic signaling and glucose metabolism, ultimately leading to a further increase in mitochondrial dysfunction. Interventions to improve mitochondrial function have been shown to correct insulin metabolic signaling and other metabolic and cardiovascular abnormalities. This review explores mechanisms of mitochondrial dysfunction with a focus on impaired oxidative phosphorylation and mitochondrial biogenesis in the pathophysiology of metabolic heart disease.
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Affiliation(s)
- Jun Ren
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA
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41
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Lopaschuk GD, Ussher JR, Folmes CDL, Jaswal JS, Stanley WC. Myocardial fatty acid metabolism in health and disease. Physiol Rev 2010; 90:207-58. [PMID: 20086077 DOI: 10.1152/physrev.00015.2009] [Citation(s) in RCA: 1459] [Impact Index Per Article: 104.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
There is a constant high demand for energy to sustain the continuous contractile activity of the heart, which is met primarily by the beta-oxidation of long-chain fatty acids. The control of fatty acid beta-oxidation is complex and is aimed at ensuring that the supply and oxidation of the fatty acids is sufficient to meet the energy demands of the heart. The metabolism of fatty acids via beta-oxidation is not regulated in isolation; rather, it occurs in response to alterations in contractile work, the presence of competing substrates (i.e., glucose, lactate, ketones, amino acids), changes in hormonal milieu, and limitations in oxygen supply. Alterations in fatty acid metabolism can contribute to cardiac pathology. For instance, the excessive uptake and beta-oxidation of fatty acids in obesity and diabetes can compromise cardiac function. Furthermore, alterations in fatty acid beta-oxidation both during and after ischemia and in the failing heart can also contribute to cardiac pathology. This paper reviews the regulation of myocardial fatty acid beta-oxidation and how alterations in fatty acid beta-oxidation can contribute to heart disease. The implications of inhibiting fatty acid beta-oxidation as a potential novel therapeutic approach for the treatment of various forms of heart disease are also discussed.
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Affiliation(s)
- Gary D Lopaschuk
- Cardiovascular Research Group, Mazankowski Alberta Heart Institute, University of Alberta, Alberta T6G 2S2, Canada.
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42
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Peairs A, Radjavi A, Davis S, Li L, Ahmed A, Giri S, Reilly CM. Activation of AMPK inhibits inflammation in MRL/lpr mouse mesangial cells. Clin Exp Immunol 2009; 156:542-51. [PMID: 19438609 DOI: 10.1111/j.1365-2249.2009.03924.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Recent reports show that 5-amino-4-imidazole carboxamide riboside (AICAR), a pharmacological activator of AMP-activated protein kinase (AMPK), inhibits the lipopolysaccharide (LPS)-induced production of proinflammatory cytokines. MRL/MPJ-Fas(lpr) (MRL/lpr) mice show an intrinsic decreased threshold for the production of inflammatory mediators when stimulated. In our current studies, we sought to determine if AMPK activation would inhibit inflammatory mediator production in stimulated kidney mesangial cells. Cultured mesangial cells from MRL/lpr mice were treated with AICAR and stimulated with LPS/interferon (IFN)-gamma. AICAR decreased dose-dependently inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and interleukin-6 production in LPS/IFN-gamma-stimulated mesangial cells. Mechanistically, AICAR inhibited the LPS/IFN-gamma-stimulated PI3K/Akt signalling inflammatory cascade but did not affect LPS/IFN-gamma-mediated inhibitory kappa B phosphorylation or nuclear factor (NF)-kappaB (p65) nuclear translocation. Treatment with the adenosine kinase inhibitor 5'-iodotubercidin blocked the ability of AICAR to activate AMPK and prevented AICAR from inhibiting the LPS/IFN-gamma-stimulated PI3K/Akt pathway and attenuating iNOS expression. Taken together, these observations suggest that AICAR inhibits LPS/IFN-gamma-induced Akt phosphorylation through AMPK activation and may serve as a potential therapeutic target in inflammatory diseases.
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Affiliation(s)
- A Peairs
- Virginia College of Osteopathic Medicine, Blacksburg, VA 24060, USA
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43
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AMP-activated protein kinase pathway: a potential therapeutic target in cardiometabolic disease. Clin Sci (Lond) 2009; 116:607-20. [PMID: 19275766 PMCID: PMC2762688 DOI: 10.1042/cs20080066] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AMPK (AMP-activated protein kinase) is a heterotrimetric enzyme that is expressed in many tissues, including the heart and vasculature, and plays a central role in the regulation of energy homoeostasis. It is activated in response to stresses that lead to an increase in the cellular AMP/ATP ratio caused either by inhibition of ATP production (i.e. anoxia or ischaemia) or by accelerating ATP consumption (i.e. muscle contraction or fasting). In the heart, AMPK activity increases during ischaemia and functions to sustain ATP, cardiac function and myocardial viability. There is increasing evidence that AMPK is implicated in the pathophysiology of cardiovascular and metabolic diseases. A principle mode of AMPK activation is phosphorylation by upstream kinases [e.g. LKB1 and CaMK (Ca2+/calmodulin-dependent protein kinase], which leads to direct effects on tissues and phosphorylation of various downstream kinases [e.g. eEF2 (eukaryotic elongation factor 2) kinase and p70 S6 kinase]. These upstream and downstream kinases of AMPK have fundamental roles in glucose metabolism, fatty acid oxidation, protein synthesis and tumour suppression; consequently, they have been implicated in cardiac ischaemia, arrhythmias and hypertrophy. Recent mechanistic studies have shown that AMPK has an important role in the mechanism of action of MF (metformin), TDZs (thiazolinediones) and statins. Increased understanding of the beneficial effects of AMPK activation provides the rationale for targeting AMPK in the development of new therapeutic strategies for cardiometabolic disease.
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44
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Zhao P, Wang J, He L, Ma H, Zhang X, Zhu X, Dolence EK, Ren J, Li J. Deficiency in TLR4 signal transduction ameliorates cardiac injury and cardiomyocyte contractile dysfunction during ischemia. J Cell Mol Med 2009; 13:1513-25. [PMID: 19508385 PMCID: PMC3828863 DOI: 10.1111/j.1582-4934.2009.00798.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Toll-like receptor 4 (TLR4), a proximal signalling receptor in innate immune responses to lipopolysaccharide of gram-negative pathogens, is expressed in the heart. Accumulating evidence have consolidated the notion that TLR4 plays an essential role in the pathogenesis of cardiac dysfunction. However, the molecular mechanisms of TLR4 responsible for ischemia-induced cardiac dysfunction remain unclear. To address the signalling mechanisms of TLR4-deficiency cardioprotection against ischemic injury, in vivo regional ischemia was induced by occlusion of the left anterior descending coronary artery in wild-type (WT) C3H/HeN and TLR4-mutated C3H/HeJ mice. The results demonstrated that blunted ischemic activation of p38 mitogen-activated protein kinase and JNK signalling occurred in C3H/HeJ hearts versus C3H/HeN hearts, while ERK and AMP-activated protein kinase (AMPK) signalling pathways were augmented during ischemia in C3H/HeJ hearts versus C3H/HeN hearts. Intriguingly, ischemia-stimulated endoplasmic reticulum stress was higher in C3H/HeN hearts than that in C3H/HeJ as demonstrated by up-regulation of Grp78/BiP, Gadd153/CHOP and IRE-1α. Myocardial infarct, caspase-3 activity and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining demonstrated that C3H/HeN hearts suffered more damage than those of C3H/HeJ hearts during ischemia. Moreover, isolated cardiomyocytes from C3H/HeJ hearts showed resistance to hypoxia-induced contractile dysfunction compared to those from C3H/HeN hearts, which are associated with greater hypoxic activation of AMPK and ERK signalling, better intracellular Ca2+ handling in C3H/HeJ versus C3H/HeN cardiomyocytes. These findings suggest that the cardioprotective effects against ischemic injury of hearts with deficiency in TLR4 signalling may be mediated through modulating AMPK and ERK signalling pathway during ischemia.
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Affiliation(s)
- Peng Zhao
- Department of Cardiology, Shandong Provincial Hospital, Shandong University, Jinan, China
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45
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Russell RR. Myocardial metabolic imaging: Viability and beyond. CURRENT CARDIOVASCULAR IMAGING REPORTS 2009. [DOI: 10.1007/s12410-009-0027-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Betti M, Schneider B, Wismer W, Carney V, Zuidhof M, Renema R. Omega-3-enriched broiler meat: 2. Functional properties, oxidative stability, and consumer acceptance. Poult Sci 2009; 88:1085-95. [DOI: 10.3382/ps.2008-00158] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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47
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Abstract
Over the past decade, AMP-activated protein kinase (AMPK) has emerged as an important intracellular signalling pathway in the heart. Activated AMPK stimulates the production of ATP by regulating key steps in both glucose and fatty acid metabolism. It has an inhibitory effect on cardiac protein synthesis. AMPK also interacts with additional intracellular signalling pathways in a coordinated network that modulates essential cellular processes in the heart. Evidence is accumulating that AMPK may protect the heart from ischaemic injury and limit the development of cardiac myocyte hypertrophy to various stimuli. Heart AMPK is activated by hormones, cytokines and oral hypoglycaemic drugs that are used in the treatment of type 2 diabetes. The tumour suppressor LKB1 is the major regulator of AMPK activity, but additional upstream kinases and protein phosphatases also contribute. Mutations in the regulatory gamma2 subunit of AMPK lead to an inherited syndrome of hypertrophic cardiomyopathy and ventricular pre-excitation, which appears to be due to intracellular glycogen accumulation. Future research promises to elucidate the molecular mechanisms responsible for AMPK activation, novel downstream AMPK targets, and the therapeutic potential of targeting AMPK for the prevention and treatment of myocardial ischaemia or cardiac hypertrophy.
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Affiliation(s)
- A S Kim
- Departments of Internal Medicine and Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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48
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Jian Z, Li JB, Ma RY, Chen L, Zhong QJ, Wang XF, Wang W, Hong Y, Xiao YB. Increase of macrophage migration inhibitory factor (MIF) expression in cardiomyocytes during chronic hypoxia. Clin Chim Acta 2009; 405:132-8. [PMID: 19394321 DOI: 10.1016/j.cca.2009.04.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 04/21/2009] [Accepted: 04/21/2009] [Indexed: 01/12/2023]
Abstract
BACKGROUND Macrophage migration inhibitory factor (MIF) might play an important role in the myocardium during chronic hypoxia because MIF protects the heart during myocardial ischemia by activating 5'-adenosine monophosphate activated protein kinase (AMPK). METHODS We investigated 35 infants with cyanotic or acyanotic cardiac defects and H9c2 embryonic rat cardiomyocytes to examine the effect of chronic hypoxia on the expression of MIF in vivo and in vitro, respectively. RESULTS We found out an increase of endogenous cardiac MIF expression positively correlated with degree of hypoxia. Also, AMPK activation was elevated while MIF expression was increased in cells exposed to long periods of hypoxia in vitro. There was no significant difference in the growth ratio of cells cultivated in long periods of hypoxia and normoxia. CONCLUSIONS The expression of MIF is significantly increased in cardiomyocytes exposed to chronic hypoxia, and the activation of AMPK was increased accordingly.
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Affiliation(s)
- Zhao Jian
- Department of Cardiovascular Surgery, Xinqiao Hospital, Third Military Medical University, 183 Xinqiao Street, Chongqing 400037, PR China
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49
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Lopaschuk GD. AMP-activated protein kinase control of energy metabolism in the ischemic heart. Int J Obes (Lond) 2009; 32 Suppl 4:S29-35. [PMID: 18719595 DOI: 10.1038/ijo.2008.120] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Myocardial ischemia produces an energy-deficient state in heart muscle, which if not corrected can lead to cardiomyocyte death. AMP-activated protein kinase (AMPK) is a key kinase that can increase energy production in the ischemic heart. During ischemia a rapid activation of AMPK occurs, resulting in an activation of both myocardial glucose uptake and glycolysis, as well as an increase in fatty acid oxidation. This activation of AMPK has the potential to increase energy production, thereby protecting the heart during ischemic stress. However, at clinically relevant high levels of fatty acids, ischemia-induced activation of AMPK also stimulates fatty acid oxidation during and following ischemia. This can contribute to ischemic injury secondary to an inhibition of glucose oxidation, which results in a decrease in cardiac efficiency. As a result, AMPK activation has the potential to be either beneficial or harmful in the ischemic heart.
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Affiliation(s)
- G D Lopaschuk
- Cardiovascular Research Group, Departments of Pediatrics and Pharmacology, Faculty of Medicine, University of Alberta, Edmonton, AB, Canada.
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50
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Ussher JR, Lopaschuk GD. Targeting malonyl CoA inhibition of mitochondrial fatty acid uptake as an approach to treat cardiac ischemia/reperfusion. Basic Res Cardiol 2009; 104:203-10. [PMID: 19242641 DOI: 10.1007/s00395-009-0003-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 01/22/2009] [Accepted: 01/30/2009] [Indexed: 12/21/2022]
Abstract
Cardiovascular disease is the major cause of death and disability in the world, with ischemic heart disease accounting for the vast majority of this health problem. Current treatments for ischemic heart disease are primarily aimed at either increasing blood and oxygen supply to the heart or decreasing the heart's oxygen demand. A novel treatment strategy involves increasing the efficiency of oxygen use by the heart. During and following ischemia, the heart can become inefficient in using oxygen, due in part to an excessive use of fatty acids as a source of fuel. One potential strategy to increase cardiac efficiency is to inhibit this use of fatty acid oxidation as a fuel source, while stimulating the use of glucose oxidation as a fuel source, which allows the heart to produce energy more efficiently and reduces the acidosis associated with ischemia/reperfusion, both of which are beneficial to the heart. Malonyl CoA is a potent endogenous inhibitor of cardiac fatty acid oxidation, secondary to inhibition of carnitine palmitoyl transferase-I, the gatekeeper of mitochondrial fatty acid uptake. Malonyl CoA is synthesized in the heart by acetyl CoA carboxylase and degraded by malonyl CoA decarboxylase (MCD). Strategies aimed at increasing cardiac malonyl CoA levels, such as via inhibition of MCD, are associated with a decrease in fatty acid oxidation rates, and a parallel increase in glucose oxidation rates. This is associated with a decrease in acidosis and an improvement in cardiac function and efficiency during and following ischemia. Therefore, targeting malonyl CoA is a novel exciting approach for the treatment of cardiac ischemia/reperfusion.
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Affiliation(s)
- John R Ussher
- Department of Pediatrics, 423 Heritage Medical Research Center, University of Alberta, Edmonton, Canada
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