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Nakanishi A, Hatano N, Fujiwara Y, Sha'ri A, Takabatake S, Akano H, Kanayama N, Magari M, Nozaki N, Tokumitsu H. AMP-activated protein kinase-mediated feedback phosphorylation controls the Ca 2+/calmodulin (CaM) dependence of Ca 2+/CaM-dependent protein kinase kinase β. J Biol Chem 2017; 292:19804-19813. [PMID: 28974582 DOI: 10.1074/jbc.m117.805085] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 09/18/2017] [Indexed: 11/06/2022] Open
Abstract
The Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ)/5'-AMP-activated protein kinase (AMPK) phosphorylation cascade affects various Ca2+-dependent metabolic pathways and cancer growth. Unlike recombinant CaMKKβ that exhibits higher basal activity (autonomous activity), activation of the CaMKKβ/AMPK signaling pathway requires increased intracellular Ca2+ concentrations. Moreover, the Ca2+/CaM dependence of CaMKKβ appears to arise from multiple phosphorylation events, including autophosphorylation and activities furnished by other protein kinases. However, the effects of proximal downstream kinases on CaMKKβ activity have not yet been evaluated. Here, we demonstrate feedback phosphorylation of CaMKKβ at multiple residues by CaMKKβ-activated AMPK in addition to autophosphorylation in vitro, leading to reduced autonomous, but not Ca2+/CaM-activated, CaMKKβ activity. MS analysis and site-directed mutagenesis of AMPK phosphorylation sites in CaMKKβ indicated that Thr144 phosphorylation by activated AMPK converts CaMKKβ into a Ca2+/CaM-dependent enzyme as shown by completely Ca2+/CaM-dependent CaMKK activity of a phosphomimetic T144E CaMKKβ mutant. CaMKKβ mutant analysis indicated that the C-terminal domain (residues 471-587), including the autoinhibitory region, plays an important role in stabilizing an inactive conformation in a Thr144 phosphorylation-dependent manner. Furthermore, immunoblot analysis with anti-phospho-Thr144 antibody revealed phosphorylation of Thr144 in CaMKKβ in transfected COS-7 cells that was further enhanced by exogenous expression of AMPKα. These results indicate that AMPK-mediated feedback phosphorylation of CaMKKβ regulates the CaMKKβ/AMPK signaling cascade and may be physiologically important for intracellular maintenance of Ca2+-dependent AMPK activation by CaMKKβ.
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Affiliation(s)
- Akihiro Nakanishi
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Naoya Hatano
- The Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan, and
| | - Yuya Fujiwara
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Arian Sha'ri
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Shota Takabatake
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Hiroki Akano
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Naoki Kanayama
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Masaki Magari
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | | | - Hiroshi Tokumitsu
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan,
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52
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Morgan AH, Andrews ZB, Davies JS. Less is more: Caloric regulation of neurogenesis and adult brain function. J Neuroendocrinol 2017; 29. [PMID: 28771924 DOI: 10.1111/jne.12512] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/20/2017] [Accepted: 07/26/2017] [Indexed: 12/11/2022]
Abstract
Calorie intake is essential for regulating normal physiological processes and is fundamental to maintaining life. Indeed, both extremes of calorie intake result in increased morbidity and mortality. In this review, we discuss the effect of calorie intake on adult brain function, with an emphasis on the beneficial effects of mild calorie restriction. Recent findings relating to the regenerative and protective effects of the gastrointestinal hormone, ghrelin, suggest that it may underlie the beneficial effects of calorie restriction. We discuss the putative cellular mechanisms underlying the action of ghrelin and their possible role in supporting healthy brain ageing.
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Affiliation(s)
- A H Morgan
- Molecular Neurobiology, Institute of Life Science, School of Medicine, Swansea University, Swansea, UK
| | - Z B Andrews
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - J S Davies
- Molecular Neurobiology, Institute of Life Science, School of Medicine, Swansea University, Swansea, UK
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53
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Jiang F. Autophagy in vascular endothelial cells. Clin Exp Pharmacol Physiol 2017; 43:1021-1028. [PMID: 27558982 DOI: 10.1111/1440-1681.12649] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/30/2016] [Accepted: 08/08/2016] [Indexed: 12/18/2022]
Abstract
The importance of autophagy in cardiovascular physiology and cardiovascular disease is increasingly recognized; however, the precise biological effects and underlying mechanisms of autophagy in the cardiovascular system are still poorly understood. In the last few years, the effects of autophagy in endothelial cells have attracted great interests. This article provides a summary of our current knowledge on the regulatory factors, signalling mechanisms, and functional outcomes of autophagy in endothelial cells. It is suggested that in most situations, induction of an autophagic response has cytoprotective effects. The beneficial effects of autophagy in endothelial cells are likely to be context-dependent, since autophagy may also contribute to cell death under certain circumstances. In addition to regulating endothelial cell survival or death, autophagy is also involved in modulating other important functions, such as nitric oxide production, angiogenesis and haemostasis/thrombosis. The mounting data will help us draw a clear picture of the roles of autophagy in endothelial cell biology and dysfunction. Given the pivotal role of endothelial dysfunction in the pathogenesis of vascular disease, disruptions of autophagy in endothelial cells are likely to have significant contributions. This is supported by some preliminary ex vivo data indicating that compromised autophagic functions may be important in the development of endothelial dysfunctions associated with diabetes and ageing.
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Affiliation(s)
- Fan Jiang
- Department of Pathology and Pathophysiology, School of Basic Medicine, Shandong University, Jinan, Shandong Province, China.
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54
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Bootman MD, Chehab T, Bultynck G, Parys JB, Rietdorf K. The regulation of autophagy by calcium signals: Do we have a consensus? Cell Calcium 2017; 70:32-46. [PMID: 28847414 DOI: 10.1016/j.ceca.2017.08.005] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/14/2017] [Accepted: 08/14/2017] [Indexed: 12/12/2022]
Abstract
Macroautophagy (hereafter called 'autophagy') is a cellular process for degrading and recycling cellular constituents, and for maintenance of cell function. Autophagy initiates via vesicular engulfment of cellular materials and culminates in their degradation via lysosomal hydrolases, with the whole process often being termed 'autophagic flux'. Autophagy is a multi-step pathway requiring the interplay of numerous scaffolding and signalling molecules. In particular, orthologs of the family of ∼30 autophagy-regulating (Atg) proteins that were first characterised in yeast play essential roles in the initiation and processing of autophagic vesicles in mammalian cells. The serine/threonine kinase mTOR (mechanistic target of rapamycin) is a master regulator of the canonical autophagic response of cells to nutrient starvation. In addition, AMP-activated protein kinase (AMPK), which is a key sensor of cellular energy status, can trigger autophagy by inhibiting mTOR, or by phosphorylating other downstream targets. Calcium (Ca2+) has been implicated in autophagic signalling pathways encompassing both mTOR and AMPK, as well as in autophagy seemingly not involving these kinases. Numerous studies have shown that cytosolic Ca2+ signals can trigger autophagy. Moreover, introduction of an exogenous chelator to prevent cytosolic Ca2+ signals inhibits autophagy in response to many different stimuli, with suggestions that buffering Ca2+ affects not only the triggering of autophagy, but also proximal and distal steps during autophagic flux. Observations such as these indicate that Ca2+ plays an essential role as a pro-autophagic signal. However, cellular Ca2+ signals can exert anti-autophagic actions too. For example, Ca2+ channel blockers induce autophagy due to the loss of autophagy-suppressing Ca2+ signals. In addition, the sequestration of Ca2+ by mitochondria during physiological signalling appears necessary to maintain cellular bio-energetics, thereby suppressing AMPK-dependent autophagy. This article attempts to provide an integrated overview of the evidence for the proposed roles of various Ca2+ signals, Ca2+ channels and Ca2+ sources in controlling autophagic flux.
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Affiliation(s)
- Martin D Bootman
- School of Life, Health and Chemical Sciences, The Open University, MK7 6AA, UK.
| | - Tala Chehab
- School of Life, Health and Chemical Sciences, The Open University, MK7 6AA, UK
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), B-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), B-3000 Leuven, Belgium
| | - Katja Rietdorf
- School of Life, Health and Chemical Sciences, The Open University, MK7 6AA, UK
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55
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Poillet-Perez L, Jacquet M, Hervouet E, Gauthier T, Fraichard A, Borg C, Pallandre JR, Gonzalez BJ, Ramdani Y, Boyer-Guittaut M, Delage-Mourroux R, Despouy G. GABARAPL1 tumor suppressive function is independent of its conjugation to autophagosomes in MCF-7 breast cancer cells. Oncotarget 2017; 8:55998-56020. [PMID: 28915569 PMCID: PMC5593540 DOI: 10.18632/oncotarget.19639] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 07/18/2017] [Indexed: 12/19/2022] Open
Abstract
The GABARAPL1 protein belongs to the ATG8 family whose members are involved in autophagy. Our laboratory previously demonstrated that GABARAPL1 associates with autophagic vesicles, regulates autophagic flux and acts as a tumor suppressor protein in breast cancer. In this study, we aimed to determine whether GABARAPL1 conjugation to autophagosomes is necessary for its tumor suppressive functions using the MCF-7 breast cancer cell line overexpressing GABARAPL1 or a G116A mutant, which is unable to be lipidated and associated to autophagosomes. We show that the G116A mutation impaired GABARAPL1 function in autophagosome/lysosome fusion and inhibited lysosome activity but did not alter MTOR and ULK1 activities or tumor growth in vivo. Our results demonstrate for the first time that GABARAPL1 plays different regulatory functions during early and late stages of autophagy, independently or not of its conjugation to autophagosomes, but its tumor suppressive function appeared to be independent of its conjugation to autophagic vesicles.
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Affiliation(s)
- Laura Poillet-Perez
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France.,Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - Marine Jacquet
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Eric Hervouet
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Thierry Gauthier
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Annick Fraichard
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Christophe Borg
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Jean-René Pallandre
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Bruno J Gonzalez
- Microvascular Endothelium and Neonatal Brain Lesions, Université de Normandie, UFR de Médecine et de Pharmacie, Rouen, France
| | - Yasmina Ramdani
- Microvascular Endothelium and Neonatal Brain Lesions, Université de Normandie, UFR de Médecine et de Pharmacie, Rouen, France
| | - Michaël Boyer-Guittaut
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Régis Delage-Mourroux
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
| | - Gilles Despouy
- Unité Mixte de Recherche, Interactions Hôte-Greffon-Tumeur, Ingénierie Cellulaire et Génique, Université Bourgogne Franche-Comté, Besançon, France
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56
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Liou B, Peng Y, Li R, Inskeep V, Zhang W, Quinn B, Dasgupta N, Blackwood R, Setchell KDR, Fleming S, Grabowski GA, Marshall J, Sun Y. Modulating ryanodine receptors with dantrolene attenuates neuronopathic phenotype in Gaucher disease mice. Hum Mol Genet 2017; 25:5126-5141. [PMID: 27655403 DOI: 10.1093/hmg/ddw322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/14/2016] [Indexed: 12/12/2022] Open
Abstract
Neuronopathic Gaucher disease (nGD) manifests as severe neurological symptoms in patients with no effective treatment available. Ryanodine receptors (Ryrs) are a family of calcium release channels on intracellular stores. The goal of this study is to determine if Ryrs are potential targets for nGD treatment. A nGD cell model (CBE-N2a) was created by inhibiting acid β-glucosidase (GCase) in N2a cells with conduritol B epoxide (CBE). Enhanced cytosolic calcium in CBE-N2a cells was blocked by either ryanodine or dantrolene, antagonists of Ryrs and by Genz-161, a glucosylceramide synthase inhibitor, suggesting substrate-mediated ER-calcium efflux occurs through ryanodine receptors. In the brain of a nGD (4L;C*) mouse model, expression of Ryrs was normal at 13 days of age, but significantly decreased below the wild type level in end-stage 4L;C* brains at 40 days. Treatment with dantrolene in 4L;C* mice starting at postnatal day 5 delayed neurological pathology and prolonged survival. Compared to untreated 4L;C* mice, dantrolene treatment significantly improved gait, reduced LC3-II levels, improved mitochondrial ATP production and reduced inflammation in the brain. Dantrolene treatment partially normalized Ryr expression and its potential regulators, CAMK IV and calmodulin. Furthermore, dantrolene treatment increased residual mutant GCase activity in 4L;C* brains. These data demonstrate that modulating Ryrs has neuroprotective effects in nGD through mechanisms that protect the mitochondria, autophagy, Ryr expression and enhance GCase activity. This study suggests that calcium signalling stabilization, e.g. with dantrolene, could be a potential disease modifying therapy for nGD.
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Affiliation(s)
- Benjamin Liou
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Yanyan Peng
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Ronghua Li
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Venette Inskeep
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Wujuan Zhang
- Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Brian Quinn
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Nupur Dasgupta
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Rachel Blackwood
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Kenneth D R Setchell
- Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Sheila Fleming
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Gregory A Grabowski
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | | | - Ying Sun
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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57
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Meseguer S, Boix O, Navarro-González C, Villarroya M, Boutoual R, Emperador S, García-Arumí E, Montoya J, Armengod ME. microRNA-mediated differential expression of TRMU, GTPBP3 and MTO1 in cell models of mitochondrial-DNA diseases. Sci Rep 2017; 7:6209. [PMID: 28740091 PMCID: PMC5524753 DOI: 10.1038/s41598-017-06553-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/14/2017] [Indexed: 11/12/2022] Open
Abstract
Mitochondrial diseases due to mutations in the mitochondrial (mt) DNA are heterogeneous in clinical manifestations but usually include OXPHOS dysfunction. Mechanisms by which OXPHOS dysfunction contributes to the disease phenotype invoke, apart from cell energy deficit, maladaptive responses to mitochondria-to-nucleus retrograde signaling. Here we used five different cybrid models of mtDNA diseases to demonstrate that the expression of the nuclear-encoded mt-tRNA modification enzymes TRMU, GTPBP3 and MTO1 varies in response to specific pathological mtDNA mutations, thus altering the modification status of mt-tRNAs. Importantly, we demonstrated that the expression of TRMU, GTPBP3 and MTO1 is regulated by different miRNAs, which are induced by retrograde signals like ROS and Ca2+ via different pathways. Our data suggest that the up- or down-regulation of the mt-tRNA modification enzymes is part of a cellular response to cope with a stoichiometric imbalance between mtDNA- and nuclear-encoded OXPHOS subunits. However, this miRNA-mediated response fails to provide full protection from the OXPHOS dysfunction; rather, it appears to aggravate the phenotype since transfection of the mutant cybrids with miRNA antagonists improves the energetic state of the cells, which opens up options for new therapeutic approaches.
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Affiliation(s)
- Salvador Meseguer
- Laboratory of RNA Modification and Mitochondrial Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain.
| | - Olga Boix
- Laboratory of RNA Modification and Mitochondrial Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Carmen Navarro-González
- Laboratory of RNA Modification and Mitochondrial Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Magda Villarroya
- Laboratory of RNA Modification and Mitochondrial Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Rachid Boutoual
- Laboratory of RNA Modification and Mitochondrial Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Sonia Emperador
- Universidad de Zaragoza - CIBERER (node 727)-Instituto de Investigación Sanitaria de Aragón, Zaragoza, Spain
| | - Elena García-Arumí
- Hospital Universitario Vall d'Hebron (Barcelona, Spain) and Biomedical Research Networking Centre for Rare Diseases CIBERER, node 701, Barcelona, Spain
| | - Julio Montoya
- Universidad de Zaragoza - CIBERER (node 727)-Instituto de Investigación Sanitaria de Aragón, Zaragoza, Spain
| | - M-Eugenia Armengod
- Laboratory of RNA Modification and Mitochondrial Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain. .,CIBERER node 721, Valencia, Spain.
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58
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Wang P, Wang ZY. Metal ions influx is a double edged sword for the pathogenesis of Alzheimer's disease. Ageing Res Rev 2017; 35:265-290. [PMID: 27829171 DOI: 10.1016/j.arr.2016.10.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 09/08/2016] [Accepted: 10/17/2016] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) is a common form of dementia in aged people, which is defined by two pathological characteristics: β-amyloid protein (Aβ) deposition and tau hyperphosphorylation. Although the mechanisms of AD development are still being debated, a series of evidence supports the idea that metals, such as copper, iron, zinc, magnesium and aluminium, are involved in the pathogenesis of the disease. In particular, the processes of Aβ deposition in senile plaques (SP) and the inclusion of phosphorylated tau in neurofibrillary tangles (NFTs) are markedly influenced by alterations in the homeostasis of the aforementioned metal ions. Moreover, the mechanisms of oxidative stress, synaptic plasticity, neurotoxicity, autophagy and apoptosis mediate the effects of metal ions-induced the aggregation state of Aβ and phosphorylated tau on AD development. More importantly, imbalance of these mechanisms finally caused cognitive decline in different experiment models. Collectively, reconstructing the signaling network that regulates AD progression by metal ions may provide novel insights for developing chelators specific for metal ions to combat AD.
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Affiliation(s)
- Pu Wang
- College of Life and Health Sciences, Northeastern University, No. 3-11, Wenhua Road, Shenyang, 110819, PR China.
| | - Zhan-You Wang
- College of Life and Health Sciences, Northeastern University, No. 3-11, Wenhua Road, Shenyang, 110819, PR China.
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59
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Luyten T, Welkenhuyzen K, Roest G, Kania E, Wang L, Bittremieux M, Yule DI, Parys JB, Bultynck G. Resveratrol-induced autophagy is dependent on IP 3Rs and on cytosolic Ca 2. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:947-956. [PMID: 28254579 DOI: 10.1016/j.bbamcr.2017.02.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/22/2017] [Accepted: 02/25/2017] [Indexed: 12/14/2022]
Abstract
Previous work revealed that intracellular Ca2+ signals and the inositol 1,4,5-trisphosphate (IP3) receptors (IP3R) are essential to increase autophagic flux in response to mTOR inhibition, induced by either nutrient starvation or rapamycin treatment. Here, we investigated whether autophagy induced by resveratrol, a polyphenolic phytochemical reported to trigger autophagy in a non-canonical way, also requires IP3Rs and Ca2+ signaling. Resveratrol augmented autophagic flux in a time-dependent manner in HeLa cells. Importantly, autophagy induced by resveratrol (80μM, 2h) was completely abolished in the presence of 10μM BAPTA-AM, an intracellular Ca2+-chelating agent. To elucidate the IP3R's role in this process, we employed the recently established HEK 3KO cells lacking all three IP3R isoforms. In contrast to the HEK293 wt cells and to HEK 3KO cells re-expressing IP3R1, autophagic responses in HEK 3KO cells exposed to resveratrol were severely impaired. These altered autophagic responses could not be attributed to alterations in the mTOR/p70S6K pathway, since resveratrol-induced inhibition of S6 phosphorylation was not abrogated by chelating cytosolic Ca2+ or by knocking out IP3Rs. Finally, we investigated whether resveratrol by itself induced Ca2+ release. In permeabilized HeLa cells, resveratrol neither affected the sarco- and endoplasmic reticulum Ca2+ ATPase (SERCA) activity nor the IP3-induced Ca2+ release nor the basal Ca2+ leak from the ER. Also, prolonged (4 h) treatment with 100μM resveratrol did not affect subsequent IP3-induced Ca2+ release. However, in intact HeLa cells, although resveratrol did not elicit cytosolic Ca2+ signals by itself, it acutely decreased the ER Ca2+-store content irrespective of the presence or absence of IP3Rs, leading to a dampened agonist-induced Ca2+ signaling. In conclusion, these results reveal that IP3Rs and cytosolic Ca2+ signaling are fundamentally important for driving autophagic flux, not only in response to mTOR inhibition but also in response to non-canonical autophagy inducers like resveratrol. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Tomas Luyten
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium
| | - Kirsten Welkenhuyzen
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium
| | - Gemma Roest
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium
| | - Elzbieta Kania
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium
| | - Liwei Wang
- University of Rochester, Department of Pharmacology and Physiology, Rochester, NY 14642, USA
| | - Mart Bittremieux
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium
| | - David I Yule
- University of Rochester, Department of Pharmacology and Physiology, Rochester, NY 14642, USA
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium.
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-I box 802, Herestraat 49, 3000 Leuven, Belgium.
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60
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Gαq Signaling in the Regulation of Autophagy and Heart Failure. J Cardiovasc Pharmacol 2017; 69:212-214. [PMID: 28166086 DOI: 10.1097/fjc.0000000000000471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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61
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Wang F, Jia J, Rodrigues B. Autophagy, Metabolic Disease, and Pathogenesis of Heart Dysfunction. Can J Cardiol 2017; 33:850-859. [PMID: 28389131 DOI: 10.1016/j.cjca.2017.01.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 12/12/2022] Open
Abstract
In normal physiology, autophagy is recognized as a protective housekeeping mechanism that enables elimination of unhealthy organelles, protein aggregates, and invading pathogens, as well as recycling cell components and producing new building blocks and energy for cellular renovation and homeostasis. However, overactive or depressed autophagy is often associated with the pathogenesis of multiple disorders, including cardiac disease. During metabolic disorders, such as diabetes and obesity, dysregulation of autophagy frequently leads to cell death, cardiomyopathy, and cardiac dysfunction. In this article, we summarize the current understanding of autophagy-its classification, progression, and regulation; its roles in both physiological and pathophysiological conditions; and the balance between autophagy and apoptosis. We also explore how dysregulation of autophagy leads to cell death in models of metabolic disease and its contributing factors-including nutrient state, hyperglycemia, dyslipidemia, insulin inefficiency, and oxidative stress-and outline some recent efforts to restore normal autophagy in pathophysiological states. This information could provide potential targets for the prevention of, or intervention in, cardiac failure in metabolic disorders such as diabetes and obesity.
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Affiliation(s)
- Fulong Wang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jocelyn Jia
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
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62
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Cramer SL, Saha A, Liu J, Tadi S, Tiziani S, Yan W, Triplett K, Lamb C, Alters SE, Rowlinson S, Zhang YJ, Keating MJ, Huang P, DiGiovanni J, Georgiou G, Stone E. Systemic depletion of L-cyst(e)ine with cyst(e)inase increases reactive oxygen species and suppresses tumor growth. Nat Med 2017; 23:120-127. [PMID: 27869804 PMCID: PMC5218918 DOI: 10.1038/nm.4232] [Citation(s) in RCA: 364] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/14/2016] [Indexed: 02/07/2023]
Abstract
Cancer cells experience higher oxidative stress from reactive oxygen species (ROS) than do non-malignant cells because of genetic alterations and abnormal growth; as a result, maintenance of the antioxidant glutathione (GSH) is essential for their survival and proliferation. Under conditions of elevated ROS, endogenous L-cysteine (L-Cys) production is insufficient for GSH synthesis. This necessitates uptake of L-Cys that is predominantly in its disulfide form, L-cystine (CSSC), via the xCT(-) transporter. We show that administration of an engineered and pharmacologically optimized human cyst(e)inase enzyme mediates sustained depletion of the extracellular L-Cys and CSSC pool in mice and non-human primates. Treatment with this enzyme selectively causes cell cycle arrest and death in cancer cells due to depletion of intracellular GSH and ensuing elevated ROS; yet this treatment results in no apparent toxicities in mice even after months of continuous treatment. Cyst(e)inase suppressed the growth of prostate carcinoma allografts, reduced tumor growth in both prostate and breast cancer xenografts and doubled the median survival time of TCL1-Tg:p53-/- mice, which develop disease resembling human chronic lymphocytic leukemia. It was observed that enzyme-mediated depletion of the serum L-Cys and CSSC pool suppresses the growth of multiple tumors, yet is very well tolerated for prolonged periods, suggesting that cyst(e)inase represents a safe and effective therapeutic modality for inactivating antioxidant cellular responses in a wide range of malignancies.
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MESH Headings
- Animals
- Blotting, Western
- Breast Neoplasms/metabolism
- Cell Line, Tumor
- Cystathionine gamma-Lyase/pharmacology
- Cysteine/drug effects
- Cysteine/metabolism
- Cystine/drug effects
- Cystine/metabolism
- Female
- Glutathione/metabolism
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Macaca fascicularis
- Male
- Mice
- Mice, Knockout
- Mice, Transgenic
- Neoplasm Transplantation
- Oxidative Stress
- Polyethylene Glycols/pharmacology
- Prostatic Neoplasms/metabolism
- Reactive Oxygen Species/metabolism
- Tumor Suppressor Protein p53/genetics
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Affiliation(s)
- Shira L. Cramer
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
| | - Achinto Saha
- Division of Pharmacology and Toxicology and Dell Pediatric Research Institute, The University of Texas at Austin, Austin, TX 78712, United States
| | - Jinyun Liu
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States
| | - Surendar Tadi
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, TX 78712, United States
| | - Stefano Tiziani
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, TX 78712, United States
| | - Wupeng Yan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, United States
| | - Kendra Triplett
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, United States
| | - Candice Lamb
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, United States
| | | | | | - Yan Jessie Zhang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, United States
| | - Michael J. Keating
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States
| | - Peng Huang
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States
| | - John DiGiovanni
- Division of Pharmacology and Toxicology and Dell Pediatric Research Institute, The University of Texas at Austin, Austin, TX 78712, United States
| | - George Georgiou
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, United States
| | - Everett Stone
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, United States
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63
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A systems study reveals concurrent activation of AMPK and mTOR by amino acids. Nat Commun 2016; 7:13254. [PMID: 27869123 PMCID: PMC5121333 DOI: 10.1038/ncomms13254] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 09/13/2016] [Indexed: 12/17/2022] Open
Abstract
Amino acids (aa) are not only building blocks for proteins, but also signalling molecules, with the mammalian target of rapamycin complex 1 (mTORC1) acting as a key mediator. However, little is known about whether aa, independently of mTORC1, activate other kinases of the mTOR signalling network. To delineate aa-stimulated mTOR network dynamics, we here combine a computational–experimental approach with text mining-enhanced quantitative proteomics. We report that AMP-activated protein kinase (AMPK), phosphatidylinositide 3-kinase (PI3K) and mTOR complex 2 (mTORC2) are acutely activated by aa-readdition in an mTORC1-independent manner. AMPK activation by aa is mediated by Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ). In response, AMPK impinges on the autophagy regulators Unc-51-like kinase-1 (ULK1) and c-Jun. AMPK is widely recognized as an mTORC1 antagonist that is activated by starvation. We find that aa acutely activate AMPK concurrently with mTOR. We show that AMPK under aa sufficiency acts to sustain autophagy. This may be required to maintain protein homoeostasis and deliver metabolite intermediates for biosynthetic processes. mTORC1 is known to mediate the signalling activity of amino acids. Here, the authors combine modelling with experiments and find that amino acids acutely stimulate mTORC2, IRS/PI3K and AMPK, independently of mTORC1. AMPK activation through CaMKKβ sustains autophagy under non-starvation conditions.
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64
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Sun F, Xu X, Wang X, Zhang B. Regulation of autophagy by Ca 2. Tumour Biol 2016; 37:10.1007/s13277-016-5353-y. [PMID: 27864685 PMCID: PMC5250648 DOI: 10.1007/s13277-016-5353-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 09/07/2016] [Indexed: 01/20/2023] Open
Abstract
Autophagy is an evolutionarily conserved lysosomal catabolic process used as an internal engine in response to nutrient starvation or metabolic stress. A number of protein complexes and an intricate network of stress signaling cascades impinge on the regulation of autophagy; the mammalian target of rapamycin serves as a canonical player. Ca2+, as a major intracellular second messenger, regulates multiple physiological and pathological functions. Although significant information is already well-established about the role of Ca2+ in apoptosis, its role in autophagy has been recently determined and is poorly understood. Intracellular Ca2+ positively and negatively affects autophagy. In this review, evidence for both views and the interplay of Ca2+ between autophagy and apoptosis induction are discussed. The available data revealed the bidirectional role of Ca2+ in the regulation of autophagy. Moreover, the data also indicated that this role probably depends on the context of time, space, Ca2+ source, and cell state, thus either preventing or enhancing autophagy.
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Affiliation(s)
- Fang Sun
- Department of Clinical Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China
- Department of Obstetrics and Gynecology, Xuzhou Central Hospital, Xuzhou, Jiangsu, 221009, China
| | - Xia Xu
- Department of Obstetrics and Gynecology, Xuzhou Hospital of Traditional Chinese Medicine, Xuzhou, Jiangsu, 221002, China
| | - Xiaohong Wang
- Department of Obstetrics and Gynecology, Xuzhou Hospital of Traditional Chinese Medicine, Xuzhou, Jiangsu, 221002, China
| | - Bei Zhang
- Department of Clinical Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China.
- Department of Obstetrics and Gynecology, Xuzhou Central Hospital, Xuzhou, Jiangsu, 221009, China.
- Department of Obstetrics and Gynecology, Xuzhou Central Hospital, Xuzhou, Jiangsu, 221002, China.
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65
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Yang J, Yu J, Li D, Yu S, Ke J, Wang L, Wang Y, Qiu Y, Gao X, Zhang J, Huang L. Store-operated calcium entry-activated autophagy protects EPC proliferation via the CAMKK2-MTOR pathway in ox-LDL exposure. Autophagy 2016; 13:82-98. [PMID: 27791458 DOI: 10.1080/15548627.2016.1245261] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Improving biological functions of endothelial progenitor cells (EPCs) is beneficial to maintaining endothelium homeostasis and promoting vascular re-endothelialization. Because macroautophagy/autophagy has been documented as a double-edged sword in cell functions, its effects on EPCs remain to be elucidated. This study was designed to explore the role and molecular mechanisms of store-operated calcium entry (SOCE)-activated autophagy in proliferation of EPCs under hypercholesterolemia. We employed oxidized low-density lipoprotein (ox-LDL) to mimic hypercholesterolemia in bone marrow-derived EPCs from rat. Ox-LDL dose-dependently activated autophagy flux, while inhibiting EPC proliferation. Importantly, inhibition of autophagy either by silencing Atg7 or by 3-methyladenine treatment, further aggravated proliferative inhibition by ox-LDL, suggesting the protective effects of autophagy against ox-LDL. Interestingly, ox-LDL increased STIM1 expression and intracellular Ca2+ concentration. Either Ca2+ chelators or deficiency in STIM1 attenuated ox-LDL-induced autophagy activation, confirming the involvement of SOCE in the process. Furthermore, CAMKK2 (calcium/calmodulin-dependent protein kinase kinase 2, β) activation and MTOR (mechanistic target of rapamycin [serine/threonine kinase]) deactivation were associated with autophagy modulation. Together, our results reveal a novel signaling pathway of SOCE-CAMKK2 in the regulation of autophagy and offer new insights into the important roles of autophagy in maintaining proliferation and promoting the survival capability of EPCs. This may be beneficial to improving EPC transplantation efficacy and enhancing vascular re-endothelialization in patients with hypercholesterolemia.
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Affiliation(s)
- Jie Yang
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Jie Yu
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Dongdong Li
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Sanjiu Yu
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Jingbin Ke
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Lianyou Wang
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Yanwei Wang
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Youzhu Qiu
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Xubin Gao
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Jihang Zhang
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
| | - Lan Huang
- a Institute of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University , Chongqing , China
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66
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Ali M, Devkota S, Roh JI, Lee J, Lee HW. Telomerase reverse transcriptase induces basal and amino acid starvation-induced autophagy through mTORC1. Biochem Biophys Res Commun 2016; 478:1198-204. [DOI: 10.1016/j.bbrc.2016.08.094] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/16/2016] [Indexed: 01/06/2023]
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67
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Wang S, Chen Y, Kou R, Wang Y, Zeng T, Xie K, Song F. Carbon disulfide activates p62-Nrf2-keap1 pathway in rat nerve tissues. Toxicology 2016; 368-369:19-27. [DOI: 10.1016/j.tox.2016.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/29/2016] [Accepted: 08/13/2016] [Indexed: 12/30/2022]
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68
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Mukherjee K, Ghoshal B, Ghosh S, Chakrabarty Y, Shwetha S, Das S, Bhattacharyya SN. Reversible HuR-microRNA binding controls extracellular export of miR-122 and augments stress response. EMBO Rep 2016; 17:1184-203. [PMID: 27402548 PMCID: PMC4967961 DOI: 10.15252/embr.201541930] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 06/09/2016] [Indexed: 01/10/2023] Open
Abstract
microRNAs (miRNAs), the tiny but stable regulatory RNAs in metazoan cells, can undergo selective turnover in presence of specific internal and external cues to control cellular response against the changing environment. We have observed reduction in cellular miR-122 content, due to their accelerated extracellular export in human hepatic cells starved for small metabolites including amino acids. In this context, a new role of human ELAV protein HuR has been identified. HuR, a negative regulator of miRNA function, accelerates extracellular vesicle (EV)-mediated export of miRNAs in human cells. In stressed cells, HuR replaces miRNPs from target messages and is both necessary and sufficient for the extracellular export of corresponding miRNAs. HuR could reversibly bind miRNAs to replace them from Ago2 and subsequently itself gets freed from bound miRNAs upon ubiquitination. The ubiquitinated form of HuR is predominantly associated with multivesicular bodies (MVB) where HuR-unbound miRNAs also reside. These MVB-associated pool of miRNAs get exported out via EVs thereby delimiting cellular miR-122 level during starvation. Therefore, by modulating extracellular export of miR-122, HuR could control stress response in starved human hepatic cells.
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Affiliation(s)
- Kamalika Mukherjee
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Bartika Ghoshal
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Souvik Ghosh
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Yogaditya Chakrabarty
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Shivaprasad Shwetha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Saumitra Das
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Suvendra N Bhattacharyya
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
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69
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Pan H, Zhong XP, Lee S. Sustained activation of mTORC1 in macrophages increases AMPKα-dependent autophagy to maintain cellular homeostasis. BMC BIOCHEMISTRY 2016; 17:14. [PMID: 27387347 PMCID: PMC4937593 DOI: 10.1186/s12858-016-0069-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/29/2016] [Indexed: 12/25/2022]
Abstract
Background The mechanistic target of rapamycin complex 1 (mTORC1) is a well-conserved serine/threonine protein kinase that controls autophagy as well as many other processes such as protein synthesis, cell growth, and metabolism. The activity of mTORC1 is stringently and negatively controlled by the tuberous sclerosis proteins 1 and 2 complex (TSC1/2). Results In contrast to the previous studies using Tsc1 knockout mouse embryonic fibroblasts (MEF) cells, we demonstrated evidence that TSC1 deficient macrophages exhibited enhanced basal and mycobacterial infection-induced autophagy via AMPKα-dependent phosphorylation of ULK1 (Ser555). These effects were concomitant with constitutive activation of mTORC1 and can be reversed by addition of amino acids or rapamycin, and by the knockdown of the regulatory-associated protein of mTOR, Raptor. In addition, increased autophagy in TSC1 deficient macrophages resulted in suppression of inflammation during mycobacterial infection, which was reversed upon amino acid treatment of the TSC1 deficient macrophages. We further demonstrated that TSC1 conditional knockout mice infected with Mycobacterium tuberculosis, the causative agent of tuberculosis, resulted in less bacterial burden and a comparable level of inflammation when compared to wild type mice. Conclusions Our data revealed that sustained activation of mTORC1 due to defects in TSC1 promotes AMPKα-dependent autophagic flux to maintain cellular homeostasis.
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Affiliation(s)
- Hongjie Pan
- Human Vaccine Institute and Department of Medicine, Duke University, Durham, NC, 27710, USA
| | - Xiao-Ping Zhong
- Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Sunhee Lee
- Human Vaccine Institute and Department of Medicine, Duke University, Durham, NC, 27710, USA.
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70
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Monahan Z, Shewmaker F, Pandey UB. Stress granules at the intersection of autophagy and ALS. Brain Res 2016; 1649:189-200. [PMID: 27181519 DOI: 10.1016/j.brainres.2016.05.022] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/06/2016] [Accepted: 05/12/2016] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive, fatal disease caused by loss of upper and lower motor neurons. The majority of ALS cases are classified as sporadic (80-90%), with the remaining considered familial based on patient history. The last decade has seen a surge in the identification of ALS-causing genes - including TARDBP (TDP-43), FUS, MATR3 (Matrin-3), C9ORF72 and several others - providing important insights into the molecular pathways involved in pathogenesis. Most of the protein products of ALS-linked genes fall into two functional categories: RNA-binding/homeostasis and protein-quality control (i.e. autophagy and proteasome). The RNA-binding proteins tend to be aggregation-prone with low-complexity domains similar to the prion-forming domains of yeast. Many also incorporate into stress granules (SGs), which are cytoplasmic ribonucleoprotein complexes that form in response to cellular stress. Mutant forms of TDP-43 and FUS perturb SG dynamics, lengthening their cytoplasmic persistence. Recent evidence suggests that SGs are regulated by the autophagy pathway, suggesting a unifying connection between many of the ALS-linked genes. Persistent SGs may give rise to intractable aggregates that disrupt neuronal homeostasis, thus failure to clear SGs by autophagic processes may promote ALS pathogenesis. This article is part of a Special Issue entitled SI:Autophagy.
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Affiliation(s)
- Zachary Monahan
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Frank Shewmaker
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Udai Bhan Pandey
- Department of Pediatrics, Division of Child Neurology, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, United States; Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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71
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Fujiwara Y, Kawaguchi Y, Fujimoto T, Kanayama N, Magari M, Tokumitsu H. Differential AMP-activated Protein Kinase (AMPK) Recognition Mechanism of Ca2+/Calmodulin-dependent Protein Kinase Kinase Isoforms. J Biol Chem 2016; 291:13802-8. [PMID: 27151216 DOI: 10.1074/jbc.m116.727867] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Indexed: 11/06/2022] Open
Abstract
Ca(2+)/calmodulin-dependent protein kinase kinase β (CaMKKβ) is a known activating kinase for AMP-activated protein kinase (AMPK). In vitro, CaMKKβ phosphorylates Thr(172) in the AMPKα subunit more efficiently than CaMKKα, with a lower Km (∼2 μm) for AMPK, whereas the CaMKIα phosphorylation efficiencies by both CaMKKs are indistinguishable. Here we found that subdomain VIII of CaMKK is involved in the discrimination of AMPK as a native substrate by measuring the activities of various CaMKKα/CaMKKβ chimera mutants. Site-directed mutagenesis analysis revealed that Leu(358) in CaMKKβ/Ile(322) in CaMKKα confer, at least in part, a distinct recognition of AMPK but not of CaMKIα.
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Affiliation(s)
- Yuya Fujiwara
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan and
| | - Yoshinori Kawaguchi
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan and
| | | | - Naoki Kanayama
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan and
| | - Masaki Magari
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan and
| | - Hiroshi Tokumitsu
- From the Division of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan and
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72
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Wang JD, Cao YL, Li Q, Yang YP, Jin M, Chen D, Wang F, Wang GH, Qin ZH, Hu LF, Liu CF. A pivotal role of FOS-mediated BECN1/Beclin 1 upregulation in dopamine D2 and D3 receptor agonist-induced autophagy activation. Autophagy 2015; 11:2057-2073. [PMID: 26649942 PMCID: PMC4824582 DOI: 10.1080/15548627.2015.1100930] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Autophagy dysfunction is implicated in the pathogenesis of Parkinson disease (PD). BECN1/Beclin 1 acts as a critical regulator of autophagy and other cellular processes; yet, little is known about the function and regulation of BECN1 in PD. In this study, we report that dopamine D2 and D3 receptor (DRD2 and DRD3) activation by pramipexole and quinpirole could enhance BECN1 transcription and promote autophagy activation in several cell lines, including PC12, MES23.5 and differentiated SH-SY5Y cells, and also in tyrosine hydroxylase positive primary midbrain neurons. Moreover, we identified a novel FOS (FBJ murine osteosarcoma viral oncogene homolog) binding sequence (5′-TGCCTCA-3′) in the rat and human Becn1/BECN1 promoter and uncovered an essential role of FOS binding in the enhancement of Becn1 transcription in PC12 cells in response to the dopamine agonist(s). In addition, we demonstrated a critical role of intracellular Ca2+ elevation, followed by the enhanced phosphorylation of CAMK4 (calcium/calmodulin-dependent protein kinase IV) and CREB (cAMP responsive element binding protein) in the increases of FOS expression and autophagy activity. More importantly, pramipexole treatment ameliorated the SNCA/α-synuclein accumulation in rotenone-treated PC12 cells that overexpress wild-type or A53T mutant SNCA by promoting autophagy flux. This effect was also demonstrated in the substantia nigra and the striatum of SNCAA53T transgenic mice. The inhibition of SNCA accumulation by pramipexole was attenuated by cotreatment with the DRD2 and DRD3 antagonists and Becn1 siRNAs. Thus, our findings suggest that DRD2 and DRD3 agonist(s) may induce autophagy activation via a BECN1-dependent pathway and have the potential to reduce SNCA accumulation in PD.
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Affiliation(s)
- Jian-Da Wang
- a Department of Neurology ; Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases; The Second Affiliated Hospital of Soochow University; Soochow University ; Suzhou , China.,b Institute of Neuroscience; Soochow University ; Suzhou , China.,c Department of Pediatrics ; Second Affiliated Hospital; School of Medicine, Zhejiang University ; Hangzhou, Zhejiang , China
| | - Yu-Lan Cao
- a Department of Neurology ; Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases; The Second Affiliated Hospital of Soochow University; Soochow University ; Suzhou , China.,b Institute of Neuroscience; Soochow University ; Suzhou , China
| | - Qian Li
- b Institute of Neuroscience; Soochow University ; Suzhou , China.,d Department of Pharmacology ; Soochow University; College of Pharmaceutical Sciences ; Suzhou , China
| | - Ya-Ping Yang
- a Department of Neurology ; Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases; The Second Affiliated Hospital of Soochow University; Soochow University ; Suzhou , China
| | - Mengmeng Jin
- a Department of Neurology ; Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases; The Second Affiliated Hospital of Soochow University; Soochow University ; Suzhou , China
| | - Dong Chen
- d Department of Pharmacology ; Soochow University; College of Pharmaceutical Sciences ; Suzhou , China
| | - Fen Wang
- b Institute of Neuroscience; Soochow University ; Suzhou , China
| | - Guang-Hui Wang
- d Department of Pharmacology ; Soochow University; College of Pharmaceutical Sciences ; Suzhou , China
| | - Zheng-Hong Qin
- d Department of Pharmacology ; Soochow University; College of Pharmaceutical Sciences ; Suzhou , China
| | - Li-Fang Hu
- b Institute of Neuroscience; Soochow University ; Suzhou , China.,d Department of Pharmacology ; Soochow University; College of Pharmaceutical Sciences ; Suzhou , China
| | - Chun-Feng Liu
- a Department of Neurology ; Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases; The Second Affiliated Hospital of Soochow University; Soochow University ; Suzhou , China.,b Institute of Neuroscience; Soochow University ; Suzhou , China
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73
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Abstract
Pathogenic bacteria produce virulence factors called effectors, which are important components of the infection process. Effectors aid in pathogenesis by facilitating bacterial attachment, pathogen entry into or exit from the host cell, immunoevasion, and immunosuppression. Effectors also have the ability to subvert host cellular processes, such as hijacking cytoskeletal machinery or blocking protein translation. However, host cells possess an evolutionarily conserved innate immune response that can sense the pathogen through the activity of its effectors and mount a robust immune response. This “effector triggered immunity” (ETI) was first discovered in plants but recent evidence suggest that the process is also well conserved in metazoans. We will discuss salient points of the mechanism of ETI in metazoans from recent studies done in mammalian cells and invertebrate model hosts.
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Affiliation(s)
- Rajmohan Rajamuthiah
- a Division of Infectious Diseases; Rhode Island Hospital; Alpert Medical School of Brown University; Providence, RI USA
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74
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Bertrand L, Toborek M. Dysregulation of Endoplasmic Reticulum Stress and Autophagic Responses by the Antiretroviral Drug Efavirenz. Mol Pharmacol 2015; 88:304-15. [PMID: 25987489 DOI: 10.1124/mol.115.098590] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 05/15/2015] [Indexed: 12/23/2022] Open
Abstract
Increasing evidence demonstrates that the antiretroviral drugs (ARVds) used for human immunodeficiency virus (HIV) treatment have toxic effects that result in various cellular and tissue pathologies; however, their impact on the cells composing the blood-brain barrier is poorly understood. The current study focused on ARVds, used either in combination or alone, on the induction of endoplasmic reticulum (ER) stress responses in human brain endothelial cells. Among studied drugs (efavirenz, tenofovir, emtricitabine, lamivudine, and indinavir), only efavirenz increased ER stress via upregulation and activation of protein kinase-like ER kinase PERK and inositol requiring kinase 1α (IRE1α). At the same time, efavirenz diminished autophagic activity, a surprising result because typically the induction of ER stress is linked to enhanced autophagy. These results were confirmed in microvessels of HIV transgenic mice chronically administered with efavirenz. In a series of further experiments, we identified that efavirenz dysregulated ER stress and autophagy by blocking the activity of the Beclin-1/Atg14/PI3KIII complex in regard to synthesis of phosphatidylinositol 3-phosphate, a process that is linked to the formation of autophagosomes. Because autophagy is a protective mechanism involved in the removal of dysfunctional proteins and organelles, its inhibition can contribute to the toxicity of efavirenz or the development of neurodegenerative disease in HIV patients treated with this drug.
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Affiliation(s)
- Luc Bertrand
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, Florida
| | - Michal Toborek
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, Florida
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75
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Zhou X, Clister TL, Lowry PR, Seldin MM, Wong GW, Zhang J. Dynamic Visualization of mTORC1 Activity in Living Cells. Cell Rep 2015; 10:1767-1777. [PMID: 25772363 DOI: 10.1016/j.celrep.2015.02.031] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 01/15/2015] [Accepted: 02/09/2015] [Indexed: 12/18/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) senses diverse signals to regulate cell growth and metabolism. It has become increasingly clear that mTORC1 activity is regulated in time and space inside the cell, but direct interrogation of such spatiotemporal regulation is challenging. Here, we describe a genetically encoded mTORC1 activity reporter (TORCAR) that exhibits a change in FRET in response to phosphorylation by mTORC1. Co-imaging mTORC1 activity and calcium dynamics revealed that a growth-factor-induced calcium transient contributes to mTORC1 activity. Dynamic activity maps generated with the use of subcellularly targeted TORCAR uncovered mTORC1 activity not only in cytosol and at the lysosome but also in the nucleus and at the plasma membrane. Furthermore, a wide distribution of activities was observed upon growth factor stimulation, whereas leucine ester, an amino acid surrogate, induces more compartmentalized activities at the lysosome and in the nucleus. Thus, mTORC1 activities are spatiotemporally regulated in a signal-specific manner.
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Affiliation(s)
- Xin Zhou
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Terri L Clister
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pamela R Lowry
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Marcus M Seldin
- Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - G William Wong
- Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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76
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Yang CM, Huang YJ, Hsu SH. Enhanced Autophagy of Adipose-Derived Stem Cells Grown on Chitosan Substrates. Biores Open Access 2015; 4:89-96. [PMID: 26309785 PMCID: PMC4497627 DOI: 10.1089/biores.2014.0032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Autophagy is an important protein quality control mechanism for cells under stress conditions to promote cell survival. Modulation of autophagy on biomaterial substrates is rarely reported. In this study, the autophagy of adipose-derived stem cells (ADSCs) cultured on chitosan (CS) substrates was examined. Compared to the traditional monolayer culture, ADSCs cultured on CS substrates showed spheroid formation as well as a prolonged upregulation of autophagosomal marker-microtubule-associated protein 1 light chain 3 (LC3) II protein expression. In addition, the green fluorescent protein tagged-LC3 (GFP-LC3) expressing ADSCs also revealed more GFP-LC3 puncta on CS substrates. The enhanced autophagy on CS substrates was associated with Ca(2+), while ethylene glycol tetraacetic acid (EGTA), a Ca(2+) chelator, repressed the autophagy in a dose-dependent manner. Moreover, ADSC spheroids on CS substrates demonstrated a higher survival rate and autophagy response upon H2O2 treatment. The upstream components of autophagy signal pathway-UNC51-like kinase 1 (Ulk1), autophagy-related protein 13 (Atg13), and autophagy/beclin-1 regulator 1 (Ambra1) genes were more highly expressed in ADSC spheroids before and after adding H2O2 than those in the conventional culture. EGTA also decreased the cell viability and autophagy-associated gene expression for ADSC spheroids on CS substrates after H2O2 treatment. Therefore, we suggest that three-dimensional (3D) cell culture on CS may confer ADSCs the ability to increase the autophagic flux in response to stimulations in a Ca(2+)-dependent manner.
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Affiliation(s)
- Ching-Ming Yang
- Institute of Polymer Science and Engineering, National Taiwan University, Taipei, Taiwan
| | - Yen-Jang Huang
- Institute of Polymer Science and Engineering, National Taiwan University, Taipei, Taiwan
| | - Shan-hui Hsu
- Institute of Polymer Science and Engineering, National Taiwan University, Taipei, Taiwan
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan
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77
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Lim JA, Li L, Kakhlon O, Myerowitz R, Raben N. Defects in calcium homeostasis and mitochondria can be reversed in Pompe disease. Autophagy 2015; 11:385-402. [PMID: 25758767 PMCID: PMC4502791 DOI: 10.1080/15548627.2015.1009779] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/08/2014] [Accepted: 11/28/2014] [Indexed: 02/08/2023] Open
Abstract
Mitochondria-induced oxidative stress and flawed autophagy are common features of neurodegenerative and lysosomal storage diseases (LSDs). Although defective autophagy is particularly prominent in Pompe disease, mitochondrial function has escaped examination in this typical LSD. We have found multiple mitochondrial defects in mouse and human models of Pompe disease, a life-threatening cardiac and skeletal muscle myopathy: a profound dysregulation of Ca(2+) homeostasis, mitochondrial Ca(2+) overload, an increase in reactive oxygen species, a decrease in mitochondrial membrane potential, an increase in caspase-independent apoptosis, as well as a decreased oxygen consumption and ATP production of mitochondria. In addition, gene expression studies revealed a striking upregulation of the β 1 subunit of L-type Ca(2+) channel in Pompe muscle cells. This study provides strong evidence that disturbance of Ca(2+) homeostasis and mitochondrial abnormalities in Pompe disease represent early changes in a complex pathogenetic cascade leading from a deficiency of a single lysosomal enzyme to severe and hard-to-treat autophagic myopathy. Remarkably, L-type Ca(2+)channel blockers, commonly used to treat other maladies, reversed these defects, indicating that a similar approach can be beneficial to the plethora of lysosomal and neurodegenerative disorders.
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Key Words
- AIFM1, apoptosis-inducing factor, mitochondrion-associated, 1
- CCCP, carbonyl cyanide m-chlorophenylhydrazone
- DMEM, Dulbecco's modified Eagle's medium
- EGTA, ethylene glycol-bis(2-aminoethylether)-N, N, N′, N′-tetraacetic acid
- ERT, enzyme replacement therapy
- GAA, glucosidase
- GFP, green fluorescent protein
- LAMP1, lysosomal-associated membrane protein 1
- LSD, lysosomal storage disease
- MAP1LC3A/B (LC3), microtubule-associated protein 1 light chain 3 α/β
- MOPS, 3-morpholinopropane-1-sulfonic acid
- MitoG, MitoTracker Green
- OMM, outer mitochondrial membrane
- Pompe disease
- RFP, red fluorescent protein
- ROS, reactive oxygen species
- TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling
- Ub, ubiquitinated
- VDCC, voltage-dependent Ca2+ channel
- autophagy
- calcium
- lysosome
- mitochondria
- mitophagy
- α, acid
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Affiliation(s)
- Jeong-A Lim
- Laboratory of Muscle Stem Cells and Gene Regulation; National Institute of Arthritis and Musculoskeletal and Skin Diseases; National Institutes of Health; Bethesda; MD USA
| | - Lishu Li
- Laboratory of Muscle Stem Cells and Gene Regulation; National Institute of Arthritis and Musculoskeletal and Skin Diseases; National Institutes of Health; Bethesda; MD USA
| | - Or Kakhlon
- Department of Neurology; Hadassah-Hebrew University Medical Center; Ein Kerem; Jerusalem, Israel
| | - Rachel Myerowitz
- Laboratory of Muscle Stem Cells and Gene Regulation; National Institute of Arthritis and Musculoskeletal and Skin Diseases; National Institutes of Health; Bethesda; MD USA
- St. Mary's College of Maryland; St. Mary's City, MD USA
| | - Nina Raben
- Laboratory of Muscle Stem Cells and Gene Regulation; National Institute of Arthritis and Musculoskeletal and Skin Diseases; National Institutes of Health; Bethesda; MD USA
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78
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Yu X, Long YC, Shen HM. Differential regulatory functions of three classes of phosphatidylinositol and phosphoinositide 3-kinases in autophagy. Autophagy 2015; 11:1711-28. [PMID: 26018563 PMCID: PMC4824607 DOI: 10.1080/15548627.2015.1043076] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/11/2015] [Accepted: 04/14/2015] [Indexed: 02/06/2023] Open
Abstract
Autophagy is an evolutionarily conserved and exquisitely regulated self-eating cellular process with important biological functions. Phosphatidylinositol 3-kinases (PtdIns3Ks) and phosphoinositide 3-kinases (PI3Ks) are involved in the autophagic process. Here we aim to recapitulate how 3 classes of these lipid kinases differentially regulate autophagy. Generally, activation of the class I PI3K suppresses autophagy, via the well-established PI3K-AKT-MTOR (mechanistic target of rapamycin) complex 1 (MTORC1) pathway. In contrast, the class III PtdIns3K catalytic subunit PIK3C3/Vps34 forms a protein complex with BECN1 and PIK3R4 and produces phosphatidylinositol 3-phosphate (PtdIns3P), which is required for the initiation and progression of autophagy. The class II enzyme emerged only recently as an alternative source of PtdIns3P and autophagic initiator. However, the orthodox paradigm is challenged by findings that the PIK3CB catalytic subunit of class I PI3K acts as a positive regulator of autophagy, and PIK3C3 was thought to be an amino acid sensor for MTOR, which curbs autophagy. At present, a number of PtdIns3K and PI3K inhibitors, including specific PIK3C3 inhibitors, have been developed for suppression of autophagy and for clinical applications in autophagy-related human diseases.
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Affiliation(s)
- Xinlei Yu
- a Department of Biochemistry; Yong Loo Lin School of Medicine, National University of Singapore ; Singapore
| | - Yun Chau Long
- a Department of Biochemistry; Yong Loo Lin School of Medicine, National University of Singapore ; Singapore
| | - Han-Ming Shen
- b Department of Physiology; Yong Loo Lin School of Medicine, National University of Singapore ; Singapore
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79
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Hall DP, Cost NG, Hegde S, Kellner E, Mikhaylova O, Stratton Y, Ehmer B, Abplanalp WA, Pandey R, Biesiada J, Harteneck C, Plas DR, Meller J, Czyzyk-Krzeska MF. TRPM3 and miR-204 establish a regulatory circuit that controls oncogenic autophagy in clear cell renal cell carcinoma. Cancer Cell 2014; 26:738-53. [PMID: 25517751 PMCID: PMC4269832 DOI: 10.1016/j.ccell.2014.09.015] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 08/06/2014] [Accepted: 09/25/2014] [Indexed: 12/14/2022]
Abstract
Autophagy promotes tumor growth by generating nutrients from the degradation of intracellular structures. Here we establish, using shRNAs, a dominant-negative mutant, and a pharmacologic inhibitor, mefenamic acid (MFA), that the Transient Receptor Potential Melastatin 3 (TRPM3) channel promotes the growth of clear cell renal cell carcinoma (ccRCC) and stimulates MAP1LC3A (LC3A) and MAP1LC3B (LC3B) autophagy. Increased expression of TRPM3 in RCC leads to Ca(2+) influx, activation of CAMKK2, AMPK, and ULK1, and phagophore formation. In addition, TRPM3 Ca(2+) and Zn(2+) fluxes inhibit miR-214, which directly targets LC3A and LC3B. The von Hippel-Lindau tumor suppressor (VHL) represses TRPM3 directly through miR-204 and indirectly through another miR-204 target, Caveolin 1 (CAV1).
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Affiliation(s)
- Daniel P Hall
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Nicholas G Cost
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA; Division of Pediatric Urology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Shailaja Hegde
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Emily Kellner
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Olga Mikhaylova
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Yiwen Stratton
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Birgit Ehmer
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - William A Abplanalp
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Raghav Pandey
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Jacek Biesiada
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Christian Harteneck
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, 72074 Tübingen, Germany
| | - David R Plas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
| | - Jarek Meller
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0056, USA; Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Informatics, Nicolas Copernicus University, 87-100 Torun, Poland
| | - Maria F Czyzyk-Krzeska
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA; Department of Veterans Affairs, VA Research Service, Cincinnati, OH 45220, USA.
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80
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Jiang P, Gan M, Lin WL, Yen SHC. Nutrient deprivation induces α-synuclein aggregation through endoplasmic reticulum stress response and SREBP2 pathway. Front Aging Neurosci 2014; 6:268. [PMID: 25339898 PMCID: PMC4189422 DOI: 10.3389/fnagi.2014.00268] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 09/16/2014] [Indexed: 12/25/2022] Open
Abstract
Abnormal accumulation of filamentous α-synuclein (α-syn) in neurons, regarded as Lewy bodies (LBs), are a hallmark of Parkinson disease (PD). Although the exact mechanism(s) underlying LBs formation remains unknown, autophagy and ER stress response have emerged as two important pathways affecting α-syn aggregation. In present study we tested whether cells with the tetracycline-off inducible overexpression of α-syn and accumulating α-syn aggregates can benefit from autophagy activation elicited by nutrient deprivation (ND), since this approach was reported to effectively clear cellular polyglutamine aggregates. We found that nutrient deprivation of non-induced cells did not affect cell viability, but significantly activated autophagy reflected by increasing the level of autophagy marker LC3-II and autophagic flux and decrease of endogenous α-syn. Cells with induced α-syn expression alone displayed autophagy activation in an α-syn dose-dependent manner to reach a level comparable to that found in non-induced, nutrient deprived counterparts. Nutrient deprivation also activated autophagy further in α-syn induced cells, but the extent was decreased with increase of α-syn dose, indicating α-syn overexpression reduces the responsiveness of cells to nutrient deprivation. Moreover, the nutrient deprivation enhanced α-syn aggregations concomitant with significant increase of apoptosis as well as ER stress response, SREBP2 activation and cholesterolgenesis. Importantly, α-syn aggregate accumulation and other effects caused by nutrient deprivation were counteracted by knockdown of SREBP2, treatment with cholesterol lowering agent-lovastatin, or by GRP78 overexpression, which also caused decrease of SREBP2 activity. Similar results were obtained from studies of primary neurons with α-syn overexpression under nutrient deprivation. Together our findings suggested that down-regulation of SREBP2 activity might be a means to prevent α-syn aggregation in PD via reducing cholesterol levels.
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Affiliation(s)
- Peizhou Jiang
- Department of Neuroscience, Mayo Clinic College of Medicine Jacksonville, FL, USA
| | - Ming Gan
- Department of Neuroscience, Mayo Clinic College of Medicine Jacksonville, FL, USA
| | - Wen-Lang Lin
- Department of Neuroscience, Mayo Clinic College of Medicine Jacksonville, FL, USA
| | - Shu-Hui C Yen
- Department of Neuroscience, Mayo Clinic College of Medicine Jacksonville, FL, USA
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81
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Ribas VT, Schnepf B, Challagundla M, Koch JC, Bähr M, Lingor P. Early and sustained activation of autophagy in degenerating axons after spinal cord injury. Brain Pathol 2014; 25:157-70. [PMID: 25040536 DOI: 10.1111/bpa.12170] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 06/25/2014] [Indexed: 12/16/2022] Open
Abstract
Axonal degeneration is one of the initial steps in many neurological disorders and has been associated with increased autophagic activity. Although there are increasing data on the regulation of autophagy proteins in the neuronal soma after spinal cord injury (SCI), their characterization in the axon is scarce. Here, we examined the regulation of autophagy during axonal degeneration in a rat model of SCI following a lesion at Th 8. We analyzed the morphological and ultrastructural changes in injured axons by immunohistochemical evaluation of autophagy-related proteins and electron microscopy at different time points following SCI. The expression of ULK1, Atg7 and Atg5 in damaged axons was rapidly upregulated within hours after SCI. The number of axonal LC3-positive autophagosomes was also rapidly increased after SCI and remained at an increased level for up to 6 weeks. Ultrastructural analysis showed early signs of axonal degeneration and increased autophagy. In conclusion, we show that autophagy is increased early and for a sustained period in degenerating axons after SCI and that it might be an important executive step involved in axonal degeneration. Therefore, autophagy may represent a promising target for future therapeutic interventions in the treatment of axonal degeneration in traumatic central nervous system disorders.
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82
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Sanchez AMJ, Bernardi H, Py G, Candau RB. Autophagy is essential to support skeletal muscle plasticity in response to endurance exercise. Am J Physiol Regul Integr Comp Physiol 2014; 307:R956-69. [PMID: 25121614 DOI: 10.1152/ajpregu.00187.2014] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physical exercise is a stress that can substantially modulate cellular signaling mechanisms to promote morphological and metabolic adaptations. Skeletal muscle protein and organelle turnover is dependent on two major cellular pathways: Forkhead box class O proteins (FOXO) transcription factors that regulate two main proteolytic systems, the ubiquitin-proteasome, and the autophagy-lysosome systems, including mitochondrial autophagy, and the MTORC1 signaling associated with protein translation and autophagy inhibition. In recent years, it has been well documented that both acute and chronic endurance exercise can affect the autophagy pathway. Importantly, substantial efforts have been made to better understand discrepancies in the literature on its modulation during exercise. A single bout of endurance exercise increases autophagic flux when the duration is long enough, and this response is dependent on nutritional status, since autophagic flux markers and mRNA coding for actors involved in mitophagy are more abundant in the fasted state. In contrast, strength and resistance exercises preferentially raise ubiquitin-proteasome system activity and involve several protein synthesis factors, such as the recently characterized DAGK for mechanistic target of rapamycin activation. In this review, we discuss recent progress on the impact of acute and chronic exercise on cell component turnover systems, with particular focus on autophagy, which until now has been relatively overlooked in skeletal muscle. We especially highlight the most recent studies on the factors that can impact its modulation, including the mode of exercise and the nutritional status, and also discuss the current limitations in the literature to encourage further works on this topic.
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Affiliation(s)
- Anthony M J Sanchez
- Department of Critical Care, McGill University Health Centre and Meakins-Christie Laboratories, Department of Medicine, McGill University, Montreal, Quebec, Canada; University of Perpignan Via Domitia, Laboratoire Performance Santé Altitude, EA 4604, Font-Romeu, France;
| | - Henri Bernardi
- Institut National de la Recherche Agronomique, UMR 866 Dynamique Musculaire et Métabolisme, Montpellier, France; and
| | - Guillaume Py
- Faculty of Sport Sciences, University of Montpellier 1, Montpellier, France
| | - Robin B Candau
- Faculty of Sport Sciences, University of Montpellier 1, Montpellier, France
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83
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Regulation of autophagy by amino acids and MTOR-dependent signal transduction. Amino Acids 2014; 47:2037-63. [PMID: 24880909 PMCID: PMC4580722 DOI: 10.1007/s00726-014-1765-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 05/12/2014] [Indexed: 01/05/2023]
Abstract
Amino acids not only participate in intermediary metabolism but also stimulate insulin-mechanistic target of rapamycin (MTOR)-mediated signal transduction which controls the major metabolic pathways. Among these is the pathway of autophagy which takes care of the degradation of long-lived proteins and of the elimination of damaged or functionally redundant organelles. Proper functioning of this process is essential for cell survival. Dysregulation of autophagy has been implicated in the etiology of several pathologies. The history of the studies on the interrelationship between amino acids, MTOR signaling and autophagy is the subject of this review. The mechanisms responsible for the stimulation of MTOR-mediated signaling, and the inhibition of autophagy, by amino acids have been studied intensively in the past but are still not completely clarified. Recent developments in this field are discussed.
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84
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Wauson EM, Dbouk HA, Ghosh AB, Cobb MH. G protein-coupled receptors and the regulation of autophagy. Trends Endocrinol Metab 2014; 25:274-82. [PMID: 24751357 PMCID: PMC4082244 DOI: 10.1016/j.tem.2014.03.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/14/2014] [Accepted: 03/17/2014] [Indexed: 01/06/2023]
Abstract
Autophagy is an important catabolic cellular process that eliminates damaged and unnecessary cytoplasmic proteins and organelles. Basal autophagy occurs during normal physiological conditions, but the activity of this process can be significantly altered in human diseases. Thus, defining the regulatory inputs and signals that control autophagy is essential. Nutrients are key modulators of autophagy. Although autophagy is generally accepted to be regulated in a cell-autonomous fashion, recent studies suggest that nutrients can modulate autophagy in a systemic manner by inducing the secretion of hormones and neurotransmitters that regulate G protein-coupled receptors (GPCRs). Emerging studies show that GPCRs also regulate autophagy by directly detecting extracellular nutrients. We review the role of GPCRs in autophagy regulation, highlighting their potential as therapeutic drug targets.
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Affiliation(s)
- Eric M Wauson
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA 50312, USA.
| | - Hashem A Dbouk
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA
| | - Anwesha B Ghosh
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
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85
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Hurtado de Llera A, Martin-Hidalgo D, Gil MC, Garcia-Marin LJ, Bragado MJ. The calcium/CaMKKalpha/beta and the cAMP/PKA pathways are essential upstream regulators of AMPK activity in boar spermatozoa. Biol Reprod 2014; 90:29. [PMID: 24389872 DOI: 10.1095/biolreprod.113.112797] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Spermatozoa successfully fertilize oocytes depending on cell energy-sensitive processes. We recently showed that the cell energy sensor, the AMP-activated protein kinase (AMPK), plays a relevant role in spermatozoa by regulating motility as well as plasma membrane organization and acrosomal integrity, and contributes to the maintenance of mitochondrial membrane potential. As the signaling pathways that control AMPK activity have been studied exclusively in somatic cells, our aim is to investigate the intracellular pathways that regulate AMPK phosphorylation at Thr(172) (activity) in male germ cells. Boar spermatozoa were incubated under different conditions in the presence or absence of Ca(2+), 8Br-cAMP, IBMX, PMA, the AMPK activator A769662, or inhibitors of PKA, PKC, or CaMKKalpha/beta. AMPK phosphorylation was evaluated by Western blot using anti-phospho-Thr(172)-AMPK antibody. Data show that AMPK phosphorylation in spermatozoa is potently stimulated by an elevation of cAMP levels through the activation of PKA, as the PKA inhibitor H89 blocks phospho-Thr(172)-AMPK. Another mechanism to potently activate AMPK is Ca(2+) that acts through two pathways, PKA (blocked by H89) and CaMKKalpha/beta (blocked by STO-609). Moreover, phospho-Thr(172)-AMPK levels greatly increased upon PKC activation induced by PMA, and the PKC inhibitor Ro-32-0432 inhibits TCM-induced AMPK activation. Different stimuli considered as cell stresses (rotenone, cyanide, sorbitol, and complete absence of intracellular Ca(2+) by BAPTA-AM) also cause AMPK phosphorylation in spermatozoa. In summary, AMPK activity in boar spermatozoa is regulated upstream by different kinases, such as PKA, CaMKKalpha/beta, and PKC, as well as by the essential intracellular messengers for spermatozoan function, Ca(2+) and cAMP levels.
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Affiliation(s)
- Ana Hurtado de Llera
- Research Group of Intracellular Signaling and Technology of Reproduction, School of Veterinary Medicine, University of Extremadura, Caceres, Spain
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86
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Chi Y, Gao K, Li K, Nakajima S, Kira S, Takeda M, Yao J. Purinergic control of AMPK activation by ATP released through connexin 43 hemichannels - pivotal roles in hemichannel-mediated cell injury. J Cell Sci 2014; 127:1487-99. [PMID: 24496445 DOI: 10.1242/jcs.139089] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Connexin hemichannels regulate many cell functions. However, the molecular mechanisms involved remain elusive. Hemichannel opening causes loss of ATP, we therefore speculated a potential role for AMPK in the biological actions of hemichannels. Activation of hemichannels by removal of extracellular Ca(2+) led to an efflux of ATP and a weak activation of AMPK. Unexpectedly, dysfunction of hemichannels markedly potentiated AMPK activation, which was reproduced by promotion of extracellular ATP degradation or inhibition of P2 purinoceptors but counteracted by exogenous ATP. Further analysis revealed that ATP induced a purinoceptor-dependent activation of Akt and mTOR. Suppression of Akt or mTOR augmented AMPK activation, whereas activation of Akt by transfection of cells with myristoylated Akt, a constitutively active form of Akt, abolished AMPK activation. In a pathological model of hemichannel opening triggered by Cd(2+), disclosure of hemichannels similarly enhanced AMPK activity, which protected cells from Cd(2+)-induced cell injury through suppression of mTOR. In summary, our data point to a channel-mediated mechanism for the regulation of AMPK through a purinergic signaling pathway. Furthermore, we define AMPK as a pivotal molecule that underlies the regulatory effects of hemichannels on cell survival.
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Affiliation(s)
- Yuan Chi
- Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
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87
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Calcineurin suppresses AMPK-dependent cytoprotective autophagy in cardiomyocytes under oxidative stress. Cell Death Dis 2014; 5:e997. [PMID: 24434520 PMCID: PMC4040710 DOI: 10.1038/cddis.2013.533] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/24/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
Abstract
Calcineurin signalling plays a critical role in the pathogenesis of many cardiovascular diseases. Calcineurin has been proven to affect a series of signalling pathways and to exert a proapoptotic effect in cardiomyocytes. However, whether it is able to regulate autophagy remains largely unknown. Here, we report that prolonged oxidative stress-induced activation of calcineurin contributes to the attenuation of adaptive AMP-activated protein kinase (AMPK) signalling and inhibits autophagy in cardiomyocytes. Primary cardiomyocytes exhibited rapid formation of autophagosomes, microtubule-associated protein 1 light chain 3 (LC3) expression and phosphorylation of AMPK in response to hydrogen peroxide (H2O2) treatment. However, prolonged (12 h) H2O2 treatment attenuated these effects and was accompanied by a significant increase in calcineurin activity and apoptosis. Inhibition of calcineurin by FK506 restored AMPK function and LC3 expression, and decreased the extent of apoptosis caused by prolonged oxidative stress. In contrast, overexpression of the constitutively active form of calcineurin markedly attenuated the increase in LC3 induced by short-term (3 h) H2O2 treatment and sensitised cells to apoptosis. In addition, FK506 failed to induce autophagy and alleviate apoptosis in cardiomyocytes expressing a kinase-dead K45R AMPK mutant. Furthermore, inhibition of autophagy by 3-methylanine (3-MA) or by knockdown of the essential autophagy-related gene ATG7 abrogated the protective effect of FK506. These findings suggest a novel role of calcineurin in suppressing adaptive autophagy during oxidative stress by downregulating the AMPK signalling pathway. The results also provide insight into how altered calcineurin and autophagic signalling is integrated to control cell survival during oxidative stress and may guide strategies to prevent cardiac oxidative damage.
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88
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Berchtold MW, Villalobo A. The many faces of calmodulin in cell proliferation, programmed cell death, autophagy, and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:398-435. [PMID: 24188867 DOI: 10.1016/j.bbamcr.2013.10.021] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 10/24/2013] [Accepted: 10/26/2013] [Indexed: 12/21/2022]
Abstract
Calmodulin (CaM) is a ubiquitous Ca(2+) receptor protein mediating a large number of signaling processes in all eukaryotic cells. CaM plays a central role in regulating a myriad of cellular functions via interaction with multiple target proteins. This review focuses on the action of CaM and CaM-dependent signaling systems in the control of vertebrate cell proliferation, programmed cell death and autophagy. The significance of CaM and interconnected CaM-regulated systems for the physiology of cancer cells including tumor stem cells, and processes required for tumor progression such as growth, tumor-associated angiogenesis and metastasis are highlighted. Furthermore, the potential targeting of CaM-dependent signaling processes for therapeutic use is discussed.
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Key Words
- (4-[3,5-bis-[2-(4-hydroxy-3-methoxy-phenyl)-ethyl]-4,5-dihydro-pyrazol-1-yl]-benzoic acid
- (4-[3,5-bis-[2-(4-hydroxy-3-methoxy-phenyl)-vinyl]-4,5-dihydro-pyrazol-1-yl]-phenyl)-(4-methyl-piperazin-1-yl)-methanone
- (−) enantiomer of dihydropyrine 3-methyl-5-3-(4,4-diphenyl-1-piperidinyl)-propyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-piridine-3,5-dicarboxylate-hydrochloride (niguldipine)
- 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine
- 12-O-tetradecanoyl-phorbol-13-acetate
- 2-chloro-(ε-amino-Lys(75))-[6-(4-(N,N′-diethylaminophenyl)-1,3,5-triazin-4-yl]-CaM adduct
- 3′-(β-chloroethyl)-2′,4′-dioxo-3,5′-spiro-oxazolidino-4-deacetoxy-vinblastine
- 7,12-dimethylbenz[a]anthracene
- Apoptosis
- Autophagy
- B859-35
- CAPP(1)-CaM
- Ca(2+) binding protein
- Calmodulin
- Cancer biology
- Cell proliferation
- DMBA
- EBB
- FL-CaM
- FPCE
- HBC
- HBCP
- J-8
- KAR-2
- KN-62
- KN-93
- N-(4-aminobutyl)-2-naphthalenesulfonamide
- N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide
- N-(6-aminohexyl)-1-naphthalenesulfonamide
- N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide
- N-8-aminooctyl-5-iodo-naphthalenesulfonamide
- N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide
- O-(4-ethoxyl-butyl)-berbamine
- RITC-CaM
- TA-CaM
- TFP
- TPA
- W-12
- W-13
- W-5
- W-7
- fluorescein-CaM adduct
- fluphenazine-N-2-chloroethane
- norchlorpromazine-CaM adduct
- rhodamine isothiocyanate-CaM adduct
- trifluoperazine
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Affiliation(s)
- Martin W Berchtold
- Department of Biology, University of Copenhagen, Copenhagen Biocenter 4-2-09 Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Antonio Villalobo
- Instituto de Investigaciones Biomédicas, Department of Cancer Biology, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Arturo Duperier 4, E-28029 Madrid, Spain.
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89
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Macronutrient composition of the diet affects the feeding-mediated down regulation of autophagy in muscle of rainbow trout (O. mykiss). PLoS One 2013; 8:e74308. [PMID: 24069294 PMCID: PMC3771976 DOI: 10.1371/journal.pone.0074308] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 07/31/2013] [Indexed: 01/18/2023] Open
Abstract
Autophagy functions as an important catabolic mechanism by mediating the turnover of intracellular organelles and protein complexes through a lysosome dependent degradative pathway. Although the induction of autophagy by starvation has been extensively studied, we still know very little about how autophagy is regulated under normal nutritional conditions. The purpose of the present study was to characterize both in vivo and in vitro the response of the autophagy-lysosomal degradative pathway to nutrient (amino acids and carbohydrates) availability in the muscle of the carnivorous rainbow trout. We report that meal feeding is accompanied by a rapid activation of Akt, FoxO1 and the Target of Rapamycin (TOR) signaling pathways and a concomitant decrease of autophagosome formation. We also show that this effect occurs only when the proportion of dietary proteins increases at the expense of carbohydrates. Concurrently, our in vitro study on primary culture of trout muscle cells demonstrates an opposite effect of amino acids and glucose on the regulation of autophagy-lysosomal pathways. More specifically, the addition of amino acids in cell culture medium inhibited the formation of autophagosomes, whereas the addition of glucose had an opposite effect. The effect of amino acids was accompanied by an activation of TOR, considered as an important regulator of autophagosomal formation. However, the mechanisms involved in the effect of glucose were independent of Akt, TOR and AMPK and remain to be determined. Together, these results demonstrated the specific role of macronutrients as well as that of their interactions in the regulation of autophagy and highlight the interest to consider the macronutrient composition of the diets in the control of this degradative pathway.
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90
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East DA, Campanella M. Ca2+ in quality control: an unresolved riddle critical to autophagy and mitophagy. Autophagy 2013; 9:1710-9. [PMID: 24121708 DOI: 10.4161/auto.25367] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Calcium (Ca (2+)) has long been known as a ubiquitous intracellular second messenger, exploited by cells to control processes as diverse as development, proliferation, learning, muscle contraction and secretion. The spatial and temporal patterns of these Ca (2+)-associated signals, as well as their amplitude, is precisely controlled to create gradients of the ion, varying considerably depending on cell type and function. Tuning of intracellular Ca (2+) is achieved in part by the buffering role of mitochondria, whose unperturbed function is essential for maintaining cellular energy balance. Quality of mitochondria is ensured by the process of targeted autophagy or mitophagy, which depends on a molecular cascade driving the catabolic process of autophagy toward damaged or deficient organelles for elimination via the lysosomal pathway. Nonspecific and targeted autophagy are highly regulated processes fundamental to cell growth and tissue homeostasis, allowing resources to be reallocated in nutrient-deprived cells as well as being instrumental in the repair of damaged organelles or the elimination of those in excess. Given the role of Ca (2+) signaling in many fundamental cellular processes requiring precise regulation, the involvement of Ca (2+) in autophagy is still somewhat ill-defined, and only in the past few years has evidence emerged linking the two. This mini-review aims to summarize recent work implicating Ca (2+) as an important regulator of autophagy, outlining a role for Ca (2+) that may be even more critical in the regulation of targeted mitochondrial autophagy.
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Affiliation(s)
- Daniel A East
- Royal Veterinary College; University of London; London, UK
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91
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Engedal N, Torgersen ML, Guldvik IJ, Barfeld SJ, Bakula D, Sætre F, Hagen LK, Patterson JB, Proikas-Cezanne T, Seglen PO, Simonsen A, Mills IG. Modulation of intracellular calcium homeostasis blocks autophagosome formation. Autophagy 2013; 9:1475-90. [PMID: 23970164 DOI: 10.4161/auto.25900] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cellular stress responses often involve elevation of cytosolic calcium levels, and this has been suggested to stimulate autophagy. Here, however, we demonstrated that agents that alter intracellular calcium ion homeostasis and induce ER stress-the calcium ionophore A23187 and the sarco/endoplasmic reticulum Ca (2+)-ATPase inhibitor thapsigargin (TG)-potently inhibit autophagy. This anti-autophagic effect occurred under both nutrient-rich and amino acid starvation conditions, and was reflected by a strong reduction in autophagic degradation of long-lived proteins. Furthermore, we found that the calcium-modulating agents inhibited autophagosome biogenesis at a step after the acquisition of WIPI1, but prior to the closure of the autophagosome. The latter was evident from the virtually complete inability of A23187- or TG-treated cells to sequester cytosolic lactate dehydrogenase. Moreover, we observed a decrease in both the number and size of starvation-induced EGFP-LC3 puncta as well as reduced numbers of mRFP-LC3 puncta in a tandem fluorescent mRFP-EGFP-LC3 cell line. The anti-autophagic effect of A23187 and TG was independent of ER stress, as chemical or siRNA-mediated inhibition of the unfolded protein response did not alter the ability of the calcium modulators to block autophagy. Finally, and remarkably, we found that the anti-autophagic activity of the calcium modulators did not require sustained or bulk changes in cytosolic calcium levels. In conclusion, we propose that local perturbations in intracellular calcium levels can exert inhibitory effects on autophagy at the stage of autophagosome expansion and closure.
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Affiliation(s)
- Nikolai Engedal
- Centre for Molecular Medicine Norway (NCMM); Nordic EMBL Partnership; University of Oslo, Norway
| | - Maria L Torgersen
- Department of Biochemistry; Institute of Basic Medical Sciences; Faculty of Medicine; University of Oslo, Norway
| | - Ingrid J Guldvik
- Centre for Molecular Medicine Norway (NCMM); Nordic EMBL Partnership; University of Oslo, Norway
| | - Stefan J Barfeld
- Centre for Molecular Medicine Norway (NCMM); Nordic EMBL Partnership; University of Oslo, Norway
| | - Daniela Bakula
- Autophagy Laboratory; Department of Molecular Biology; Interfaculty Institute for Cell Biology; Faculty of Science; Eberhard Karls University; Tuebingen, Germany
| | - Frank Sætre
- Department of Cell Biology; Institute for Cancer Research; Norwegian Radium Hospital; Oslo University Hospital; Nydalen, Oslo Norway
| | - Linda K Hagen
- Department of Cell Biology; Institute for Cancer Research; Norwegian Radium Hospital; Oslo University Hospital; Nydalen, Oslo Norway
| | | | - Tassula Proikas-Cezanne
- Autophagy Laboratory; Department of Molecular Biology; Interfaculty Institute for Cell Biology; Faculty of Science; Eberhard Karls University; Tuebingen, Germany
| | - Per O Seglen
- Department of Cell Biology; Institute for Cancer Research; Norwegian Radium Hospital; Oslo University Hospital; Nydalen, Oslo Norway
| | - Anne Simonsen
- Department of Biochemistry; Institute of Basic Medical Sciences; Faculty of Medicine; University of Oslo, Norway
| | - Ian G Mills
- Centre for Molecular Medicine Norway (NCMM); Nordic EMBL Partnership; University of Oslo, Norway; Department of Cancer Prevention and Department of Urology; Oslo University Hospitals; Oslo, Norway
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92
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Decuypere JP, Kindt D, Luyten T, Welkenhuyzen K, Missiaen L, De Smedt H, Bultynck G, Parys JB. mTOR-Controlled Autophagy Requires Intracellular Ca(2+) Signaling. PLoS One 2013; 8:e61020. [PMID: 23565295 PMCID: PMC3614970 DOI: 10.1371/journal.pone.0061020] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 03/05/2013] [Indexed: 11/17/2022] Open
Abstract
Autophagy is a lysosomal degradation pathway important for cellular homeostasis and survival. Inhibition of the mammalian target of rapamycin (mTOR) is the best known trigger for autophagy stimulation. In addition, intracellular Ca2+ regulates autophagy, but its exact role remains ambiguous. Here, we report that the mTOR inhibitor rapamycin, while enhancing autophagy, also remodeled the intracellular Ca2+-signaling machinery. These alterations include a) an increase in the endoplasmic-reticulum (ER) Ca2+-store content, b) a decrease in the ER Ca2+-leak rate, and c) an increased Ca2+ release through the inositol 1,4,5-trisphosphate receptors (IP3Rs), the main ER-resident Ca2+-release channels. Importantly, buffering cytosolic Ca2+ with BAPTA impeded rapamycin-induced autophagy. These results reveal intracellular Ca2+ signaling as a crucial component in the canonical mTOR-dependent autophagy pathway.
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Affiliation(s)
- Jean-Paul Decuypere
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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93
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