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Cao Y, Song J, Shen S, Fu H, Li X, Xu Y, Wang A, Li X, Zhang M. Trimedazidine alleviates pulmonary artery banding-induced acute right heart dysfunction and activates PRAS40 in rats. Oncotarget 2017; 8:92064-92078. [PMID: 29190898 PMCID: PMC5696164 DOI: 10.18632/oncotarget.20752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/08/2017] [Indexed: 02/01/2023] Open
Abstract
The molecular mechanism underlying acute right heart failure (RHF) is poorly understood. We used pulmonary artery banding (PAB) to induce acute RHF characterized by a rapid rise of right ventricular pressure, and then a decrease in right ventricular pressure along with a decrease in blood pressure right after banding. We found higher brain natriuretic peptide (BNP) and beta-myosin heavy chain (βMHC) levels and lower alpha-myosin heavy chain (αMHC) levels in RHF rats than sham-operated rats. Hemodynamic indexes in rats with acute RHF were slightly improved by trimedazidine TMZ, a key inhibitor of fatty acid (FA) oxidation. TMZ also reversed downregulation of peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC-1β) and peroxisome proliferator-activated receptor alpha (PPARα) by PAB and up-regulates peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), peroxisome proliferator-activated receptor delta (PPARδ) and pyruvate dehydrogenase kinase isoform 4 (PDK4). In addition, TMZ reversed upregulation of phosphorylated Akt by PAB and increased phosphorylated proline-rich Akt-substrate 40 (PRAS40). Autophagy and apoptosis were not modified by PAB or TMZ. An acute RHF model was established in rats through 70% constriction of the pulmonary artery. TMZ treatment alleviated PAB-induced acute RHF by activating PRAS40 and upregulatingPGC-1α, PGC-1β, PPARα, PPARδ, and PDK4.
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Affiliation(s)
- Yunshan Cao
- Department of Cardiology, Gansu Provincial Hospital, Lanzhou 730000, China.,Department of Heart Failure, Shanghai East Hospital, Tongji University School of Medicine, Research Center for Translational Medicine, Shanghai 200120, China
| | - Jiyang Song
- Department of Cardiology, Gansu Provincial Hospital, Lanzhou 730000, China
| | - Shutong Shen
- Department of Cardiology, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China
| | - Heling Fu
- Animal Core Facility, Nanjing Medical University, Nanjing 210029, China
| | - Xiang Li
- Department of Intensive Care, Minhang Hospital, Fudan University, Shanghai 201100, China
| | - Ying Xu
- Intensive Care Unit, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Aqian Wang
- Department of Cardiology, Gansu Provincial Hospital, Lanzhou 730000, China
| | - Xinli Li
- Department of Cardiology, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, China
| | - Min Zhang
- Department of Pathology, Gansu Provincial Hospital, Lanzhou 730000, China
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Muthuramu I, Amin R, Postnov A, Mishra M, Aboumsallem JP, Dresselaers T, Himmelreich U, Van Veldhoven PP, Gheysens O, Jacobs F, De Geest B. Cholesterol-Lowering Gene Therapy Counteracts the Development of Non-ischemic Cardiomyopathy in Mice. Mol Ther 2017; 25:2513-2525. [PMID: 28822689 DOI: 10.1016/j.ymthe.2017.07.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/20/2017] [Accepted: 07/27/2017] [Indexed: 02/02/2023] Open
Abstract
A causal role of hypercholesterolemia in non-ischemic heart failure has never been demonstrated. Adeno-associated viral serotype 8 (AAV8)-low-density lipoprotein receptor (AAV8-LDLr) gene transfer was performed in LDLr-deficient mice without and with pressure overload induced by transverse aortic constriction (TAC). AAV8-LDLr gene therapy resulted in an 82.8% (p < 0.0001) reduction of plasma cholesterol compared with controls. Mortality rate was lower (p < 0.05) in AAV8-LDLr TAC mice compared with control TAC mice (hazard ratio for mortality 0.457, 95% confidence interval [CI] 0.237-0.882) during 8 weeks of follow-up. AAV8-LDLr gene therapy attenuated cardiac hypertrophy, reduced interstitial and perivascular fibrosis, and decreased lung congestion in TAC mice. Cardiac function, quantified by invasive hemodynamic measurements and magnetic resonance imaging, was significantly improved 8 weeks after sham operation or after TAC in AAV8-LDLr mice compared with respective control groups. Myocardial protein levels of mammalian target of rapamycin and of acetyl-coenzyme A carboxylase were strikingly decreased following cholesterol lowering in mice without and with pressure overload. AAV8-LDLr therapy potently reduced cardiac glucose uptake and counteracted metabolic remodeling following pressure overload. Furthermore, oxidative stress and myocardial apoptosis were decreased following AAV8-LDLr therapy in mice with pressure overload. In conclusion, cholesterol-lowering gene therapy potently counteracts structural and metabolic remodeling, and enhances cardiac function.
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Affiliation(s)
- Ilayaraja Muthuramu
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Ruhul Amin
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Andrey Postnov
- Nuclear Medicine & Molecular Imaging, Department of Imaging & Pathology, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Mudit Mishra
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Joseph Pierre Aboumsallem
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Tom Dresselaers
- Biomedical MRI, Department of Imaging & Pathology, Catholic University of Leuven, 3000 Leuven, Belgium; Department of Radiology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Uwe Himmelreich
- Biomedical MRI, Department of Imaging & Pathology, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Paul P Van Veldhoven
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Olivier Gheysens
- Nuclear Medicine & Molecular Imaging, Department of Imaging & Pathology, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Frank Jacobs
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Catholic University of Leuven, 3000 Leuven, Belgium
| | - Bart De Geest
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, Catholic University of Leuven, 3000 Leuven, Belgium.
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53
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Suhara T, Baba Y, Shimada BK, Higa JK, Matsui T. The mTOR Signaling Pathway in Myocardial Dysfunction in Type 2 Diabetes Mellitus. Curr Diab Rep 2017; 17:38. [PMID: 28434143 PMCID: PMC8219468 DOI: 10.1007/s11892-017-0865-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW T2DM (type 2 diabetes mellitus) is a risk factor for heart failure. The mTOR (mechanistic target of rapamycin) is a key mediator of the insulin signaling pathway. We will discuss the role of mTOR in myocardial dysfunction in T2DM. RECENT FINDINGS In T2DM, chronically activated mTOR induces multiple pathological events, including a negative feedback loop that suppresses IRS (insulin receptor substrate)-1. While short-term treatment with rapamycin, an mTOR inhibitor, is a promising strategy for cardiac diseases such as acute myocardial infarction and cardiac hypertrophy in T2DM, there are many concerns about chronic usage of rapamycin. Two mTOR complexes, mTORC1 and mTORC2, affect many molecules and processes via distinct signaling pathways that regulate cardiomyocyte function and survival. Understanding mechanisms underlying mTOR-mediated pathophysiological features in the heart is essential for developing effective therapies for cardiac diseases in the context of T2DM.
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Affiliation(s)
- Tomohiro Suhara
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
- Department of Anesthesiology, Keio University School of Medicine, Tokyo, Japan
| | - Yuichi Baba
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
- Department of Cardiology and Geriatrics, Kochi Medical School, Kochi University, Kochi, Japan
| | - Briana K Shimada
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
| | - Jason K Higa
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA
| | - Takashi Matsui
- Department of Anatomy, Biochemistry & Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo St., BSB no. 110, Honolulu, HI, 96813, USA.
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Dong B, Xue R, Sun Y, Dong Y, Liu C. Sestrin 2 attenuates neonatal rat cardiomyocyte hypertrophy induced by phenylephrine via inhibiting ERK1/2. Mol Cell Biochem 2017; 433:113-123. [PMID: 28497371 DOI: 10.1007/s11010-017-3020-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 03/21/2017] [Indexed: 11/24/2022]
Abstract
Cardiac hypertrophy is an adaptive response triggered by many physiological and pathological conditions and will lead to heart failure eventually. Sestrin 2, which is a stress-responsive protein, was reported to protect heart from ischemia reperfusion injury. However, the role of Sestrin 2 in cardiac hypertrophy remains unknown. In our present study, we aimed to explore the effects of Sestrin 2 on cardiomyocyte hypertrophy. We found that knockdown of Sestrin 2 protein aggravated cardiomyocyte hypertrophy induced by phenylephrine (PE), featured by increased hypertrophic marker ANP and cell surface area. During this process, ERK1/2 cascade was further activated, while p38, JNK1/2, and mTOR signaling pathways were not affected by downregulation of Sestrin 2. Moreover, overexpression of Sestrin 2 protein protected cardiomyocytes from PE-induced hypertrophy and ERK1/2 cascade was suppressed correspondingly. Importantly, pharmacological inhibition of ERK1/2 eliminated the exacerbated hypertrophic phenotype due to Sestrin 2 protein knockdown. In conclusion, we discovered that Sestrin 2 protected against cardiomyocyte hypertrophy induced by PE via inhibiting ERK1/2 signaling.
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Affiliation(s)
- Bin Dong
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou, 510080, China
- Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou, 510080, China
| | - Ruicong Xue
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou, 510080, China
- Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou, 510080, China
| | - Yu Sun
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou, 510080, China
- Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou, 510080, China
| | - Yugang Dong
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou, 510080, China.
- Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou, 510080, China.
| | - Chen Liu
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou, 510080, China.
- Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou, 510080, China.
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55
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Kaur A, Sharma S. Mammalian target of rapamycin (mTOR) as a potential therapeutic target in various diseases. Inflammopharmacology 2017; 25:293-312. [PMID: 28417246 DOI: 10.1007/s10787-017-0336-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/02/2017] [Indexed: 12/28/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that belongs to Phosphatidylinositol-3-kinase related kinase superfamily. The signaling pathways of mTOR are integrated through the protein complexes of mTORC1 and mTORC2. mTORC1 controls protein synthesis, cell growth, proliferation, autophagy, cell metabolism, and stress responses, whereas mTORC2 seems to regulate cell survival and polarity. Dysregulation of the mTOR pathway has been implicated in the pathophysiology of a number of disease conditions, including cancer, cardiovascular, neurodegenerative, and various renal diseases. The hyperactivation of the mTOR pathway leads to increase in cell growth and proliferation and also has been documented to stimulate tumor growth. Therefore, investigation of the involvement of mTOR and its downstream pathways in various diseases intensively preoccupied scientific community. The present review is focussed on recent advances in the understanding of the mTOR signaling pathway and its role in health and various diseases.
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Affiliation(s)
- Avileen Kaur
- Cardiovascular Division, Department of Pharmacology, I. S. F. College of Pharmacy, Moga, Punjab, 142001, India
| | - Saurabh Sharma
- Cardiovascular Division, Department of Pharmacology, I. S. F. College of Pharmacy, Moga, Punjab, 142001, India.
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56
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Reperfusion Therapy with Rapamycin Attenuates Myocardial Infarction through Activation of AKT and ERK. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:4619720. [PMID: 28373901 PMCID: PMC5360974 DOI: 10.1155/2017/4619720] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/26/2017] [Accepted: 02/14/2017] [Indexed: 01/04/2023]
Abstract
Prompt coronary reperfusion is the gold standard for minimizing injury following acute myocardial infarction. Rapamycin, mammalian target of Rapamycin (mTOR) inhibitor, exerts preconditioning-like cardioprotective effects against ischemia/reperfusion (I/R) injury. We hypothesized that Rapamycin, given at the onset of reperfusion, reduces myocardial infarct size through modulation of mTOR complexes. Adult C57 male mice were subjected to 30 min of myocardial ischemia followed by reperfusion for 1 hour/24 hours. Rapamycin (0.25 mg/kg) or DMSO (7.5%) was injected intracardially at the onset of reperfusion. Post-I/R survival (87%) and cardiac function (fractional shortening, FS: 28.63 ± 3.01%) were improved in Rapamycin-treated mice compared to DMSO (survival: 63%, FS: 17.4 ± 2.6%). Rapamycin caused significant reduction in myocardial infarct size (IS: 26.2 ± 2.2%) and apoptosis (2.87 ± 0.64%) as compared to DMSO-treated mice (IS: 47.0 ± 2.3%; apoptosis: 7.39 ± 0.81%). Rapamycin induced phosphorylation of AKT S473 (target of mTORC2) but abolished ribosomal protein S6 phosphorylation (target of mTORC1) after I/R. Rapamycin induced phosphorylation of ERK1/2 but inhibited p38 phosphorylation. Infarct-limiting effect of Rapamycin was abolished with ERK inhibitor, PD98059. Rapamycin also attenuated Bax and increased Bcl-2/Bax ratio. These results suggest that reperfusion therapy with Rapamycin protects the heart against I/R injury by selective activation of mTORC2 and ERK with concurrent inhibition of mTORC1 and p38.
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57
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MicroRNA-365 accelerates cardiac hypertrophy by inhibiting autophagy via the modulation of Skp2 expression. Biochem Biophys Res Commun 2017; 484:304-310. [PMID: 28130111 DOI: 10.1016/j.bbrc.2017.01.108] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/21/2017] [Indexed: 01/15/2023]
Abstract
Evidence is emerging of a tight link between cardiomyocyte autophagy and cardiac hypertrophy (CH). Sustained exposure to stress leads CH to progress to heart failure. Several miRNAs have been described in heart failure, and miRNA-based therapeutic approaches are being pursued. Although microRNA-365 (miR-365) has been testified as a positive modulator of CH, the specific mechanism remains unclear. In the present study, we observed that miR-365 expression was up-regulated in hypertrophic cardiomyocytes both in vivo and in vitro, and was accompanied by dysregulation of autophagy. We found that miR-365 negatively modulates autophagy in hypertrophic cardiomyocytes by targeting Skp2. Overexpression of Skp2 promoted autophagy and rescued CH induced by Ang-II; conversely, Skp2 knockdown further inhibited autophagy and CH. Furthermore, we found that the activation of mammalian target of rapamycin (mTOR) signaling was regulated by Skp2 following Ang-II treatment, as indicated by the up-regulation of p-S6K and p-4EBP1 levels. The inactivation of mTOR by rapamycin completely abolished the Ang-II-induced inhibition of autophagy. In conclusion, our study provides substantial evidence that miR-365 and its target gene Skp2 play a functional role in CH and suggests the development of novel therapeutic options based on miR-365 and Skp2.
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58
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Weeks KL, Bernardo BC, Ooi JYY, Patterson NL, McMullen JR. The IGF1-PI3K-Akt Signaling Pathway in Mediating Exercise-Induced Cardiac Hypertrophy and Protection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1000:187-210. [PMID: 29098623 DOI: 10.1007/978-981-10-4304-8_12] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Regular physical activity or exercise training can lead to heart enlargement known as cardiac hypertrophy. Cardiac hypertrophy is broadly defined as an increase in heart mass. In adults, cardiac hypertrophy is often considered a poor prognostic sign because it often progresses to heart failure. Heart enlargement in a setting of cardiac disease is referred to as pathological cardiac hypertrophy and is typically characterized by cell death and depressed cardiac function. By contrast, physiological cardiac hypertrophy, as occurs in response to chronic exercise training (i.e. the 'athlete's heart'), is associated with normal or enhanced cardiac function. The following chapter describes the morphologically distinct types of heart growth, and the key role of the insulin-like growth factor 1 (IGF1) - phosphoinositide 3-kinase (PI3K)-Akt signaling pathway in regulating exercise-induced physiological cardiac hypertrophy and cardiac protection. Finally we summarize therapeutic approaches that target the IGF1-PI3K-Akt signaling pathway which are showing promise in preclinical models of heart disease.
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Affiliation(s)
- Kate L Weeks
- Baker Heart & Diabetes Institute, P.O. Box 6492, Melbourne, VIC, 3004, Australia.
| | - Bianca C Bernardo
- Baker Heart & Diabetes Institute, P.O. Box 6492, Melbourne, VIC, 3004, Australia
| | - Jenny Y Y Ooi
- Baker Heart & Diabetes Institute, P.O. Box 6492, Melbourne, VIC, 3004, Australia
| | - Natalie L Patterson
- Baker Heart & Diabetes Institute, P.O. Box 6492, Melbourne, VIC, 3004, Australia
| | - Julie R McMullen
- Baker Heart & Diabetes Institute, P.O. Box 6492, Melbourne, VIC, 3004, Australia.
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59
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Abstract
Exercise-induced cardiac remodeling is typically an adaptive response associated with cardiac myocyte hypertrophy and renewal, increased cardiac myocyte contractility, sarcomeric remodeling, cell survival, metabolic and mitochondrial adaptations, electrical remodeling, and angiogenesis. Initiating stimuli/triggers of cardiac remodeling include increased hemodynamic load, increased sympathetic activity, and the release of hormones and growth factors. Prolonged and strenuous exercise may lead to maladaptive exercise-induced cardiac remodeling including cardiac dysfunction and arrhythmia. In addition, this article describes novel therapeutic approaches for the treatment of heart failure that target mechanisms responsible for adaptive exercise-induced cardiac remodeling, which are being developed and tested in preclinical models.
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Affiliation(s)
- Bianca C Bernardo
- Baker IDI Heart and Diabetes Institute, Cardiac Hypertrophy Laboratory, PO Box 6492, Melbourne, VIC 3004, Australia
| | - Julie R McMullen
- Baker IDI Heart and Diabetes Institute, Cardiac Hypertrophy Laboratory, PO Box 6492, Melbourne, VIC 3004, Australia; Department of Medicine, Central Clinical School, Monash University, 99 Commercial Road, Melbourne, VIC 3004, Australia; Department of Physiology, Monash University, Wellington Road, Clayton, VIC 3800, Australia.
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60
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Liu R, Kenney JW, Manousopoulou A, Johnston HE, Kamei M, Woelk CH, Xie J, Schwarzer M, Garbis SD, Proud CG. Quantitative Non-canonical Amino Acid Tagging (QuaNCAT) Proteomics Identifies Distinct Patterns of Protein Synthesis Rapidly Induced by Hypertrophic Agents in Cardiomyocytes, Revealing New Aspects of Metabolic Remodeling. Mol Cell Proteomics 2016; 15:3170-3189. [PMID: 27512079 PMCID: PMC5054342 DOI: 10.1074/mcp.m115.054312] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 01/16/2023] Open
Abstract
Cardiomyocytes undergo growth and remodeling in response to specific pathological or physiological conditions. In the former, myocardial growth is a risk factor for cardiac failure and faster protein synthesis is a major factor driving cardiomyocyte growth. Our goal was to quantify the rapid effects of different pro-hypertrophic stimuli on the synthesis of specific proteins in ARVC and to determine whether such effects are caused by alterations on mRNA abundance or the translation of specific mRNAs. Cardiomyocytes have very low rates of protein synthesis, posing a challenging problem in terms of studying changes in the synthesis of specific proteins, which also applies to other nondividing primary cells. To study the rates of accumulation of specific proteins in these cells, we developed an optimized version of the Quantitative Noncanonical Amino acid Tagging LC/MS proteomic method to label and selectively enrich newly synthesized proteins in these primary cells while eliminating the suppressive effects of pre-existing and highly abundant nonisotope-tagged polypeptides. Our data revealed that a classical pathologic (phenylephrine; PE) and the recently identified insulin stimulus that also contributes to the development of pathological cardiac hypertrophy (insulin), both increased the synthesis of proteins involved in, e.g. glycolysis, the Krebs cycle and beta-oxidation, and sarcomeric components. However, insulin increased synthesis of many metabolic enzymes to a greater extent than PE. Using a novel validation method, we confirmed that synthesis of selected candidates is indeed up-regulated by PE and insulin. Synthesis of all proteins studied was up-regulated by signaling through mammalian target of rapamycin complex 1 without changes in their mRNA levels, showing the key importance of translational control in the rapid effects of hypertrophic stimuli. Expression of PKM2 was up-regulated in rat hearts following TAC. This isoform possesses specific regulatory properties, so this finding indicates it may be involved in metabolic remodeling and also serve as a novel candidate biomarker. Levels of translation factor eEF1 also increased during TAC, likely contributing to faster cell mass accumulation. Interestingly those two candidates were not up-regulated in pregnancy or exercise induced CH, indicating PKM2 and eEF1 were pathological CH specific markers. We anticipate that the methodologies described here will be valuable for other researchers studying protein synthesis in primary cells.
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Affiliation(s)
- Rui Liu
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom; §South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia
| | - Justin W Kenney
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Antigoni Manousopoulou
- From the ‡Center for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom; ¶Clinical and Experimental Sciences Unit, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Harvey E Johnston
- From the ‡Center for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom; ‖Cancer Sciences Unit, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Makoto Kamei
- §South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia
| | - Christopher H Woelk
- ¶Clinical and Experimental Sciences Unit, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Jianling Xie
- §South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia
| | - Michael Schwarzer
- **Department of Cardiovascular Surgery, Jena University Hospital-Friedrich Schiller University of Jena, Erlanger Allee 101, 07747 Jena, Germany
| | - Spiros D Garbis
- From the ‡Center for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom; ¶Clinical and Experimental Sciences Unit, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK; ‖Cancer Sciences Unit, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK;
| | - Christopher G Proud
- From the ‡Center for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom; §South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia; School of Biological Sciences, University of Adelaide, Adelaide, SA5005, Australia
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61
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Shin MJ, Kim DW, Jo HS, Cho SB, Park JH, Lee CH, Yeo EJ, Choi YJ, Kim JA, Hwang JS, Sohn EJ, Jeong JH, Kim DS, Kwon HY, Cho YJ, Lee K, Han KH, Park J, Eum WS, Choi SY. Tat-PRAS40 prevent hippocampal HT-22 cell death and oxidative stress induced animal brain ischemic insults. Free Radic Biol Med 2016; 97:250-262. [PMID: 27317854 DOI: 10.1016/j.freeradbiomed.2016.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/27/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022]
Abstract
Proline rich Akt substrate (PRAS40) is a component of mammalian target of rapamycin complex 1 (mTORC1) and is known to play an important role against reactive oxygen species-induced cell death. However, the precise function of PRAS40 in ischemia remains unclear. Thus, we investigated whether Tat-PRAS40, a cell-permeable fusion protein, has a protective function against oxidative stress-induced hippocampal neuronal (HT-22) cell death in an animal model of ischemia. We showed that Tat-PRAS40 transduced into HT-22 cells, and significantly protected against cell death by reducing the levels of H2O2 and derived reactive species, and DNA fragmentation as well as via the regulation of Bcl-2, Bax, and caspase 3 expression levels in H2O2 treated cells. Also, we showed that transduced Tat-PARS40 protein markedly increased phosphorylated RRAS40 expression levels and 14-3-3σ complex via the Akt signaling pathway. In an animal ischemia model, Tat-PRAS40 effectively transduced into the hippocampus in animal brain and significantly protected against neuronal cell death in the CA1 region. We showed that Tat-PRAS40 protein effectively transduced into hippocampal neuronal cells and markedly protected against neuronal cell damage. Therefore, we suggest that Tat-PRAS40 protein may be used as a therapeutic protein for ischemia and oxidative stress-induced brain disorders.
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Affiliation(s)
- Min Jea Shin
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
| | - Hyo Sang Jo
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Su Bin Cho
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Jung Hwan Park
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Chi Hern Lee
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Eun Ji Yeo
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Yeon Joo Choi
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Ji An Kim
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea; Bioceltran Co., Ltd., Chuncheon 24234, Republic of Korea
| | - Jung Soon Hwang
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea; Bioceltran Co., Ltd., Chuncheon 24234, Republic of Korea
| | - Eun Jeong Sohn
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Ji-Heon Jeong
- Department of Anatomy, College of Medicine, Soonchunhyang University, Cheonan-Si 31538, Republic of Korea
| | - Duk-Soo Kim
- Department of Anatomy, College of Medicine, Soonchunhyang University, Cheonan-Si 31538, Republic of Korea
| | - Hyeok Yil Kwon
- Department of Physiology, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
| | - Yong-Jun Cho
- Department of Neurosurgery, Hallym University Medical Center, Chuncheon 24253, Republic of Korea
| | - Keunwook Lee
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Kyu Hyung Han
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Jinseu Park
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Won Sik Eum
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea.
| | - Soo Young Choi
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea.
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He B, Zhao YC, Gao LC, Ying XY, Xu LW, Su YY, Ji QQ, Lin N, Pu J. Ubiquitin-Specific Protease 4 Is an Endogenous Negative Regulator of Pathological Cardiac Hypertrophy. Hypertension 2016; 67:1237-48. [PMID: 27045030 DOI: 10.1161/hypertensionaha.116.07392] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/08/2016] [Indexed: 11/16/2022]
Abstract
Dysregulation of the ubiquitin proteasome system components ubiquitin ligases and proteasome plays an important role in the pathogenesis of cardiac hypertrophy. However, little is known about the role of another ubiquitin proteasome system component, the deubiquitinating enzymes, in cardiac hypertrophy. Here, we revealed a crucial role of ubiquitin specific protease 4 (USP4), a deubiquitinating enzyme prominently expressed in the heart, in attenuating pathological cardiac hypertrophy and dysfunction. USP4 levels were consistently decreased in human failing hearts and in murine hypertrophied hearts. Adenovirus-mediated gain- and loss-of-function approaches indicated that deficiency of endogenous USP4 promoted myocyte hypertrophy induced by angiotensin II in vitro, whereas restoration of USP4 significantly attenuated the prohypertrophic effect of angiotensin II. To corroborate the role of USP4 in vivo, we generated USP4 global knockout mice and mice with cardiac-specific overexpression of USP4. Consistent with the in vitro study, USP4 depletion exacerbated the hypertrophic phenotype and cardiac dysfunction in mice subjected to pressure overload, whereas USP4 transgenic mice presented ameliorated pathological cardiac hypertrophy compared with their control littermates. Molecular analysis revealed that USP4 deficiency augmented the activation of the transforming growth factor β–activated kinase 1 (TAK1)-(JNK1/2)/P38 signaling in response to hypertrophic stress, and blockage of TAK1 activation abolished the pathological effects of USP4 deficiency in vivo. These findings provide the first evidence for the involvement of USP4 in cardiac hypertrophy, and shed light on the therapeutic potential of targeting USP4 in the treatment of cardiac hypertrophy.
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Affiliation(s)
- Ben He
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yi-Chao Zhao
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ling-Chen Gao
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Ying Ying
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Long-Wei Xu
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yuan-Yuan Su
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qing-Qi Ji
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Nan Lin
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jun Pu
- From the Department of Cardiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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63
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Chong ZZ. Targeting PRAS40 for multiple diseases. Drug Discov Today 2016; 21:1222-31. [PMID: 27086010 DOI: 10.1016/j.drudis.2016.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/18/2016] [Accepted: 04/07/2016] [Indexed: 12/19/2022]
Abstract
Proline-rich Akt substrate 40kDa (PRAS40) bridges cell signaling between protein kinase B (Akt) and the mammalian target of rapamycin complex 1 (mTORC1). Both Akt and mTORC1 can phosphorylate PRAS40. As a negative regulator of mTORC1, PRAS40 prevents the binding of mTOR to its substrates. The phosphorylation of PRAS40 results in its dissociation from mTORC1 and enhanced mTOR activation. PRAS40 in conjunction with mTORC1 has been closely associated with programmed cell death and is implicated in diabetes mellitus (DM), cardiovascular diseases, cancer, and neurological diseases. Thus, targeting PRAS40 might hold great promise for innovative therapeutic strategies for these diseases.
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Affiliation(s)
- Zhao Zhong Chong
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA; Institute of Materia Medica, Shandong Academy of Medical Sciences, Jinan, China.
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64
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Lv D, Liu J, Guo L, Wu D, Matsumoto K, Huang L. PRAS40 deregulates apoptosis in Ewing sarcoma family tumors by enhancing the insulin receptor/Akt and mTOR signaling pathways. Am J Cancer Res 2016; 6:486-497. [PMID: 27186418 PMCID: PMC4859675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023] Open
Abstract
EWS expression in Ewing sarcoma family tumors (ESFTs) is decreased due to the haploinsufficiency elicited by chromosomal translocation. The abnormal expression levels of EWS and its downstream factors contribute to the manifestation of ESFTs. Previously, we reported that increased Proline-rich Akt substrate of 40 kDa (PRAS40), which is encoded by an EWS mRNA target, promotes the development of ESFTs. However, the mechanism remains elusive. To clarify the role of PRAS40 in ESFTs, we silenced PRAS40 expression in ESFT cells using siRNAs and found increased levels of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. Cleaved caspase 3 levels and cytochrome C release were increased simultaneously. Furthermore, with PRAS40 knockdown, the phosphorylation of Akt and mTOR downstream factors, i.e., S6K and S6, was attenuated notably. Ectopic expression of PRAS40 increased Akt and S6 phosphorylation. Activation of Akt only partially reversed the apoptosis induced by PRAS40 knockdown, and downregulation of S6 phosphorylation by PRAS40 silencing could not be sufficiently restored via Akt activation. Searching the upstream factors in this pathway, the autophosphorylation of insulin receptor (IR) was found to be inhibited significantly by PRAS40 silencing but increased by PRAS40 overexpression. Therefore, PRAS40 may enhance IR phosphorylation to facilitate Akt and mTOR signaling leading to the apoptosis deregulation in ESFTs. Moreover, in vivo results confirmed that PRAS40 deletion suppressed the growth of ESFT xenografts and downregulated IR and S6 phosphorylation. Our findings suggest a novel functioning model for PRAS40, which represents a novel therapeutic target for ESFTs.
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Affiliation(s)
- Dan Lv
- Department of Pathophysiology, Dalian Medical University9 South Lvshun Road, Dalian, Liaoning 116044, P. R. China
| | - Jinye Liu
- Department of Pathophysiology, Dalian Medical University9 South Lvshun Road, Dalian, Liaoning 116044, P. R. China
| | - Lianying Guo
- Department of Pathophysiology, Dalian Medical University9 South Lvshun Road, Dalian, Liaoning 116044, P. R. China
| | - Dawei Wu
- Department of Pathophysiology, Dalian Medical University9 South Lvshun Road, Dalian, Liaoning 116044, P. R. China
| | - Ken Matsumoto
- Chemical Genetics Laboratory, RIKEN2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Lin Huang
- Department of Pathophysiology, Dalian Medical University9 South Lvshun Road, Dalian, Liaoning 116044, P. R. China
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Xu L, Brink M. mTOR, cardiomyocytes and inflammation in cardiac hypertrophy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1894-903. [PMID: 26775585 DOI: 10.1016/j.bbamcr.2016.01.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/30/2015] [Accepted: 01/07/2016] [Indexed: 02/07/2023]
Abstract
Mammalian target of rapamycin (mTOR) is an evolutionary conserved kinase that senses the nutrient and energy status of cells, the availability of growth factors, stress stimuli and other cellular and environmental cues. It responds by regulating a range of cellular processes related to metabolism and growth in accordance with the available resources and intracellular needs. mTOR has distinct functions depending on its assembly in the structurally distinct multiprotein complexes mTORC1 or mTORC2. Active mTORC1 enhances processes including glycolysis, protein, lipid and nucleotide biosynthesis, and it inhibits autophagy. Reported functions for mTORC2 after growth factor stimulation are very diverse, are tissue and cell-type specific, and include insulin-stimulated glucose transport and enhanced glycogen synthesis. In accordance with its cellular functions, mTOR has been demonstrated to regulate cardiac growth in response to pressure overload and is also known to regulate cells of the immune system. The present manuscript presents recently obtained insights into mechanisms whereby mTOR may change anabolic, catabolic and stress response pathways in cardiomocytes and discusses how mTOR may affect inflammatory cells in the heart during hemodynamic stress. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Lifen Xu
- Department of Biomedicine, University of Basel and University Hospital Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland
| | - Marijke Brink
- Department of Biomedicine, University of Basel and University Hospital Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland.
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Tan VP, Miyamoto S. Nutrient-sensing mTORC1: Integration of metabolic and autophagic signals. J Mol Cell Cardiol 2016; 95:31-41. [PMID: 26773603 DOI: 10.1016/j.yjmcc.2016.01.005] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/11/2015] [Accepted: 01/04/2016] [Indexed: 12/26/2022]
Abstract
The ability of adult cardiomyocytes to regenerate is limited, and irreversible loss by cell death plays a crucial role in heart diseases. Autophagy is an evolutionarily conserved cellular catabolic process through which long-lived proteins and damaged organelles are targeted for lysosomal degradation. Autophagy is important in cardiac homeostasis and can serve as a protective mechanism by providing an energy source, especially in the face of sustained starvation. Cellular metabolism is closely associated with cell survival, and recent evidence suggests that metabolic and autophagic signaling pathways exhibit a high degree of crosstalk and are functionally interdependent. In this review, we discuss recent progress in our understanding of regulation of autophagy and its crosstalk with metabolic signaling, with a focus on the nutrient-sensing mTOR complex 1 (mTORC1) pathway.
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Affiliation(s)
- Valerie P Tan
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA
| | - Shigeki Miyamoto
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA.
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67
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Ackermann MA. Links between mTOR and the immunoproteasome: Therapeutic targets for cardiac hypertrophy? J Mol Cell Cardiol 2015; 89:113-5. [DOI: 10.1016/j.yjmcc.2015.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 09/22/2015] [Indexed: 12/16/2022]
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Basheer W, Shaw R. The "tail" of Connexin43: An unexpected journey from alternative translation to trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1848-56. [PMID: 26526689 DOI: 10.1016/j.bbamcr.2015.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
Abstract
With each heartbeat, Connexin43 (Cx43) cell-cell communication gap junctions are needed to rapidly spread and coordinate excitation signals for an effective heart contraction. The correct formation and delivery of channels to their respective membrane subdomain is referred to as protein trafficking. Altered Cx43 trafficking is a dangerous complication of diseased myocardium which contributes to the arrhythmias of sudden cardiac death. Cx43 has also been found to regulate many other cellular processes that cannot be explained by cell-cell communication. We recently identified the existence of up to six endogenous internally translated Cx43 N-terminal truncated isoforms from the same full-length mRNA molecule. This is the first evidence that alternative translation is possible for human ion channels and in human heart. Interestingly, we found that these internally translated isoforms, more specifically the 20 kDa isoform (GJA1-20k), is important for delivery of Cx43 to its respective membrane subdomain. This review covers recent advances in Cx43 trafficking and potential importance of alternatively translated Cx43 truncated isoforms. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Wassim Basheer
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Robin Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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69
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Drolet MC, Desbiens-Brassard V, Roussel E, Tu V, Couet J, Arsenault M. Blockade of the acute activation of mTOR complex 1 decreases hypertrophy development in rats with severe aortic valve regurgitation. SPRINGERPLUS 2015; 4:435. [PMID: 26306297 PMCID: PMC4542859 DOI: 10.1186/s40064-015-1230-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/10/2015] [Indexed: 01/19/2023]
Abstract
Background Hypertrophy (H) is an adaptive response of the heart to a hemodynamic overload. Severe left ventricular (LV) volume overload (VO) from valve regurgitations (aortic (AR) or mitral regurgitation) leads to eccentric LVH. Increased protein turnover is a major event during development of LVH and the mechanistic target of rapamycin (mTOR) is a key molecule for its control. The role of mTOR inhibition in the development of LVH using rapamycin for relatively short periods of time (days to a few weeks) has been studied in the past in pressure overload models but not in VO models. We investigated if mTOR pathway was activated during LVH development in a model of severe VO (AR) in rats and if a rapamycin treatment can slow heart remodeling in this situation. Methods and Results Male rats with severe AR were studied acutely at 2 days, at 8 weeks (compensated phase) and 6 months (late phase) after VO induction. mTOR complex (mTORC) 1 (ribosomal S6 protein phosphorylation) was activated early after AR induction but not later in the disease whereas mTORC2 activity levels (Akt phosphorylation at Ser473) remained stable. We observed that a moderate dose of rapamycin (2 mg/kg/day; orally) for 8 weeks prevented severe LVH caused by AR (−46 %: p < 0.001). Rapamycin treatment specifically inhibited LV mTORC1 without altering mTORC2 activity at 8 weeks. Rapamycin also prevented cardiac myocyte hypertrophy caused by AR. Conclusion Rapamycin slows hypertrophy in LV VO by inhibiting early activation of mTORC1 without modulating mTORC2.
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Affiliation(s)
- Marie-Claude Drolet
- Groupe de Recherche sur les Valvulopathies, Centre de Recherche de l'Institut universitaire de Cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC G1V 4G5 Canada
| | - Vincent Desbiens-Brassard
- Groupe de Recherche sur les Valvulopathies, Centre de Recherche de l'Institut universitaire de Cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC G1V 4G5 Canada
| | - Elise Roussel
- Groupe de Recherche sur les Valvulopathies, Centre de Recherche de l'Institut universitaire de Cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC G1V 4G5 Canada
| | - Veronique Tu
- Groupe de Recherche sur les Valvulopathies, Centre de Recherche de l'Institut universitaire de Cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC G1V 4G5 Canada
| | - Jacques Couet
- Groupe de Recherche sur les Valvulopathies, Centre de Recherche de l'Institut universitaire de Cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC G1V 4G5 Canada
| | - Marie Arsenault
- Groupe de Recherche sur les Valvulopathies, Centre de Recherche de l'Institut universitaire de Cardiologie et pneumologie de Québec, Université Laval, 2725, Chemin Sainte-Foy, Quebec, QC G1V 4G5 Canada
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Li Z, Song Y, Liu L, Hou N, An X, Zhan D, Li Y, Zhou L, Li P, Yu L, Xia J, Zhang Y, Wang J, Yang X. miR-199a impairs autophagy and induces cardiac hypertrophy through mTOR activation. Cell Death Differ 2015; 24:1205-1213. [PMID: 26160071 PMCID: PMC5520159 DOI: 10.1038/cdd.2015.95] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/22/2015] [Accepted: 06/04/2015] [Indexed: 12/18/2022] Open
Abstract
Basal autophagy is tightly regulated by transcriptional and epigenetic factors to maintain cellular homeostasis. Dysregulation of cardiac autophagy is associated with heart diseases, including cardiac hypertrophy, but the mechanism governing cardiac autophagy is rarely identified. To analyze the in vivo function of miR-199a in cardiac autophagy and cardiac hypertrophy, we generated cardiac-specific miR-199a transgenic mice and showed that overexpression of miR-199a was sufficient to inhibit cardiomyocyte autophagy and induce cardiac hypertrophy in vivo. miR-199a impaired cardiomyocyte autophagy in a cell-autonomous manner by targeting glycogen synthase kinase 3β (GSK3β)/mammalian target of rapamycin (mTOR) complex signaling. Overexpression of autophagy related gene 5 (Atg5) attenuated the hypertrophic effects of miR-199a overexpression on cardiomyocytes, and activation of autophagy using rapamycin was sufficient to restore cardiac autophagy and decrease cardiac hypertrophy in miR-199a transgenic mice. These results reveal a novel role of miR-199a as a key regulator of cardiac autophagy, suggesting that targeting miRNAs controlling autophagy as a potential therapeutic strategy for cardiac disease.
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Affiliation(s)
- Z Li
- State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing, China
| | - Y Song
- Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, China
| | - L Liu
- State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing, China
| | - N Hou
- State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing, China
| | - X An
- Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, China
| | - D Zhan
- The First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Y Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - L Zhou
- MOE key laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - P Li
- MOE key laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - L Yu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - J Xia
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Y Zhang
- Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, China
| | - J Wang
- State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing, China
| | - X Yang
- State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing, China
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Doroudgar S, Völkers M, Thuerauf DJ, Khan M, Mohsin S, Respress JL, Wang W, Gude N, Müller OJ, Wehrens XHT, Sussman MA, Glembotski CC. Hrd1 and ER-Associated Protein Degradation, ERAD, are Critical Elements of the Adaptive ER Stress Response in Cardiac Myocytes. Circ Res 2015; 117:536-46. [PMID: 26137860 DOI: 10.1161/circresaha.115.306993] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/01/2015] [Indexed: 11/16/2022]
Abstract
RATIONALE Hydroxymethyl glutaryl-coenzyme A reductase degradation protein 1 (Hrd1) is an endoplasmic reticulum (ER)-transmembrane E3 ubiquitin ligase that has been studied in yeast, where it contributes to ER protein quality control by ER-associated degradation (ERAD) of misfolded proteins that accumulate during ER stress. Neither Hrd1 nor ERAD has been studied in the heart, or in cardiac myocytes, where protein quality control is critical for proper heart function. OBJECTIVE The objective of this study were to elucidate roles for Hrd1 in ER stress, ERAD, and viability in cultured cardiac myocytes and in the mouse heart, in vivo. METHODS AND RESULTS The effects of small interfering RNA-mediated Hrd1 knockdown were examined in cultured neonatal rat ventricular myocytes. The effects of adeno-associated virus-mediated Hrd1 knockdown and overexpression were examined in the hearts of mice subjected to pressure overload-induced pathological cardiac hypertrophy, which challenges protein-folding capacity. In cardiac myocytes, the ER stressors, thapsigargin and tunicamycin increased ERAD, as well as adaptive ER stress proteins, and minimally affected cell death. However, when Hrd1 was knocked down, thapsigargin and tunicamycin dramatically decreased ERAD, while increasing maladaptive ER stress proteins and cell death. In vivo, Hrd1 knockdown exacerbated cardiac dysfunction and increased apoptosis and cardiac hypertrophy, whereas Hrd1 overexpression preserved cardiac function and decreased apoptosis and attenuated cardiac hypertrophy in the hearts of mice subjected to pressure overload. CONCLUSIONS Hrd1 and ERAD are essential components of the adaptive ER stress response in cardiac myocytes. Hrd1 contributes to preserving heart structure and function in a mouse model of pathological cardiac hypertrophy.
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Affiliation(s)
- Shirin Doroudgar
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Mirko Völkers
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Donna J Thuerauf
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Mohsin Khan
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Sadia Mohsin
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Jonathan L Respress
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Wei Wang
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Natalie Gude
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Oliver J Müller
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Xander H T Wehrens
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Mark A Sussman
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.)
| | - Christopher C Glembotski
- From the San Diego State University Heart Institute and the Department of Biology, San Diego State University, CA (S.D., M.V., D.J.T., M.K., S.M., N.G., M.A.S., C.C.G.); Department of Cardiology, University of Heidelberg, Heidelberg, Germany (M.V.); DZKH (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, Heidelberg, Germany (M.V.); Department of Internal Medicine III (O.J.M.), University of Heidelberg, Heidelberg, Germany; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA (M.K., S.M.); and Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX (J.L.R., W.W., X.H.T.W.).
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Crozatier B, Ventura-Clapier R. Inhibition of Hypertrophy, Per Se, May Not Be a Good Therapeutic Strategy in Ventricular Pressure Overload: Other Approaches Could Be More Beneficial. Circulation 2015; 131:1448-57. [DOI: 10.1161/circulationaha.114.013895] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Bertrand Crozatier
- From Université Paris-Sud 11, and Institut National de la Santé et de la Recherche Médicale, Unit 1180, Châtenay-Malabry, France
| | - Renée Ventura-Clapier
- From Université Paris-Sud 11, and Institut National de la Santé et de la Recherche Médicale, Unit 1180, Châtenay-Malabry, France
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73
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Orogo AM, Gustafsson ÅB. Therapeutic targeting of autophagy: potential and concerns in treating cardiovascular disease. Circ Res 2015; 116:489-503. [PMID: 25634972 DOI: 10.1161/circresaha.116.303791] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Autophagy is an evolutionarily conserved process by which long-lived proteins and organelles are sequestered by autophagosomes and subsequently degraded by lysosomes for recycling. Autophagy is important for maintaining cardiac homeostasis and is a survival mechanism that is upregulated during stress or starvation. Accumulating evidence suggests that dysregulated or reduced autophagy is associated with heart failure and aging. Thus, modulating autophagy represents an attractive future therapeutic target for treating cardiovascular disease. Activation of autophagy is generally considered to be cardioprotective, whereas excessive autophagy can lead to cell death and cardiac atrophy. It is important to understand how autophagy is regulated to identify ideal therapeutic targets for treating disease. Here, we discuss the key proteins in the core autophagy machinery and describe upstream regulators that respond to extracellular and intracellular signals to tightly coordinate autophagic activity. We review various genetic and pharmacological studies that demonstrate the important role of autophagy in the heart and consider the advantages and limitations of approaches that modulate autophagy.
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Affiliation(s)
- Amabel M Orogo
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla
| | - Åsa B Gustafsson
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla.
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74
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Tham YK, Bernardo BC, Ooi JYY, Weeks KL, McMullen JR. Pathophysiology of cardiac hypertrophy and heart failure: signaling pathways and novel therapeutic targets. Arch Toxicol 2015; 89:1401-38. [DOI: 10.1007/s00204-015-1477-x] [Citation(s) in RCA: 371] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/09/2015] [Indexed: 12/18/2022]
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75
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The heart: mostly postmitotic or mostly premitotic? Myocyte cell cycle, senescence, and quiescence. Can J Cardiol 2014; 30:1270-8. [PMID: 25442430 DOI: 10.1016/j.cjca.2014.08.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/21/2014] [Accepted: 08/21/2014] [Indexed: 11/21/2022] Open
Abstract
The concept of myocyte division and myocyte-mediated regeneration has re-emerged in the past 5 years through development of sophisticated transgenic mice and carbon-dating of cells. Although recently, a couple of studies have been conducted as an attempt to intervene in myocyte division, the efficiency in adult animals remains discouragingly low. Re-enforcing myocyte division is a vision that has been desired for decades, leading to years of experience in myocyte resistance to proproliferative stimuli. Previous attempts have indeed provided a platform for basic knowledge on molecular players and signalling in myocytes. However, natural biological processes such as hypertrophy and binucleation provide layers of complexity in interpretation of previous and current findings. A major hurdle in mediating myocyte division is a lack of insight in the myocyte cell cycle. To date, no knowledge is gained on myoycte cell cycle progression and/or duration. This review will include an overview of previous and current literature on myocyte cell cycle and division. Furthermore, the limitations of current approaches and basic questions that might be essential in understanding myocardial resistance to division will be discussed.
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76
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Zhang X, Ma D, Caruso M, Lewis M, Qi Y, Yi Z. Quantitative phosphoproteomics reveals novel phosphorylation events in insulin signaling regulated by protein phosphatase 1 regulatory subunit 12A. J Proteomics 2014; 109:63-75. [PMID: 24972320 DOI: 10.1016/j.jprot.2014.06.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/11/2014] [Accepted: 06/14/2014] [Indexed: 01/07/2023]
Abstract
UNLABELLED Serine/threonine protein phosphatase 1 regulatory subunit 12A (PPP1R12A) modulates the activity and specificity of the catalytic subunit of protein phosphatase 1, regulating various cellular processes via dephosphorylation. Nonetheless, little is known about phosphorylation events controlled by PPP1R12A in skeletal muscle insulin signaling. Here, we used quantitative phosphoproteomics to generate a global picture of phosphorylation events regulated by PPP1R12A in a L6 skeletal muscle cell line, which were engineered for inducible PPP1R12A knockdown. Phosphoproteomics revealed 3876 phosphorylation sites (620 were novel) in these cells. Furthermore, PPP1R12A knockdown resulted in increased overall phosphorylation in L6 cells at the basal condition, and changed phosphorylation levels for 698 sites (assigned to 295 phosphoproteins) at the basal and/or insulin-stimulated conditions. Pathway analysis on the 295 phosphoproteins revealed multiple significantly enriched pathways related to insulin signaling, such as mTOR signaling and RhoA signaling. Moreover, phosphorylation levels for numerous regulatory sites in these pathways were significantly changed due to PPP1R12A knockdown. These results indicate that PPP1R12A indeed plays a role in skeletal muscle insulin signaling, providing novel insights into the biology of insulin action. This new information may facilitate the design of experiments to better understand mechanisms underlying skeletal muscle insulin resistance and type 2 diabetes. BIOLOGICAL SIGNIFICANCE These results identify a large number of potential new substrates of serine/threonine protein phosphatase 1 and suggest that serine/threonine protein phosphatase 1 regulatory subunit 12A indeed plays a regulatory role in multiple pathways related to insulin action, providing novel insights into the biology of skeletal muscle insulin signaling. This information may facilitate the design of experiments to better understand the molecular mechanism responsible for skeletal muscle insulin resistance and associated diseases, such as type 2 diabetes and cardiovascular diseases.
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Affiliation(s)
- Xiangmin Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Danjun Ma
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Michael Caruso
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Monique Lewis
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Yue Qi
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Zhengping Yi
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48202, USA.
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77
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Abstract
The protein kinase mammalian or mechanistic target of rapamycin (mTOR) is an atypical serine/threonine kinase that exerts its main cellular functions by interacting with specific adaptor proteins to form 2 different multiprotein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). mTORC1 regulates protein synthesis, cell growth and proliferation, autophagy, cell metabolism, and stress responses, whereas mTORC2 seems to regulate cell survival and polarity. The mTOR pathway plays a key regulatory function in cardiovascular physiology and pathology. However, the majority of information available about mTOR function in the cardiovascular system is related to the role of mTORC1 in the unstressed and stressed heart. mTORC1 is required for embryonic cardiovascular development and for postnatal maintenance of cardiac structure and function. In addition, mTORC1 is necessary for cardiac adaptation to pressure overload and development of compensatory hypertrophy. However, partial and selective pharmacological and genetic inhibition of mTORC1 was shown to extend life span in mammals, reduce pathological hypertrophy and heart failure caused by increased load or genetic cardiomyopathies, reduce myocardial damage after acute and chronic myocardial infarction, and reduce cardiac derangements caused by metabolic disorders. The optimal therapeutic strategy to target mTORC1 and increase cardioprotection is under intense investigation. This article reviews the information available regarding the effects exerted by mTOR signaling in cardiovascular physiology and pathological states.
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Affiliation(s)
- Sebastiano Sciarretta
- From the Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ (S.S., J.S.); IRCCS Neuromed, Pozzilli, Italy (S.S., M.V.); and Division of Cardiology, Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, University Sapienza, Rome, Italy (M.V.)
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Xie J, Proud CG. Signaling crosstalk between the mTOR complexes. ACTA ACUST UNITED AC 2014; 2:e28174. [PMID: 26779402 PMCID: PMC4705829 DOI: 10.4161/trla.28174] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/12/2014] [Accepted: 02/10/2014] [Indexed: 12/16/2022]
Abstract
mTOR is a protein kinase which integrates a variety of environmental and intracellular stimuli to positively regulate many anabolic processes of the cell, including protein synthesis. It exists within two highly conserved multi-protein complexes known as mTORC1 and 2 mTORC2. Each of these complexes phosphorylates different downstream targets, and play roles in different cellular functions. They also show distinctive sensitivity to the mTOR inhibitor rapamycin. Nevertheless, despite their biochemical and functional differences, recent studies have suggested that the regulation of these complexes is tightly linked to each other. For instance, both mTORC1 and 2 share some common upstream signaling molecules, such as PI3K and tuberous sclerosis complex TSC, which control their activation. Stimulation of the mTOR complexes may also trigger both positive and negative feedback mechanisms, which then in turn either further enhance or suppress their activation. Here, we summarize some recently discovered features relating to the crosstalk between mTORC1 and 2. We then discuss how aberrant mTOR complex crosstalk mechanisms may have an impact on the development of human diseases and drug resistance.
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Affiliation(s)
- Jianling Xie
- Centre for Biological Sciences; University of Southampton; Southampton, UK
| | - Chris G Proud
- Centre for Biological Sciences; University of Southampton; Southampton, UK
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Abstract
Cardiac senescence and age-related disease development have gained general attention and recognition in the past decades due to increased accessibility and quality of health care. The advancement in global civilization is complementary to concerns regarding population aging and development of chronic degenerative diseases. Cardiac degeneration has been rigorously studied. The molecular mechanisms of cardiac senescence are on multiple cellular levels and hold a multilayer complexity level, thereby hampering development of unambiguous treatment protocols. In particular, the synergistic exchange of the senescence phenotype through a senescence secretome between myocytes and stem cells appears complicated and is of great future therapeutic value. The current review article will highlight hallmarks of senescence, cardiac myocyte and stem cell senescence, and the mutual exchange of senescent secretome. Future cardiac cell therapy approaches require a comprehensive understanding of myocardial senescence to improve therapeutic efficiency as well as efficacy.
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Affiliation(s)
- Mirko Völkers
- SDSU Heart Institute and the Department of Biology; San Diego State University; San Diego, CA USA
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Bernardo BC, Ooi JY, McMullen JR. The yin and yang of adaptive and maladaptive processes in heart failure. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.ddstr.2013.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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