351
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Mulvey L, Sinclair A, Selman C. Lifespan modulation in mice and the confounding effects of genetic background. J Genet Genomics 2014; 41:497-503. [PMID: 25269675 PMCID: PMC4257991 DOI: 10.1016/j.jgg.2014.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 02/04/2023]
Abstract
We are currently in the midst of a revolution in ageing research, with several dietary, genetic and pharmacological interventions now known to modulate ageing in model organisms. Excitingly, these interventions also appear to have beneficial effects on late-life health. For example, dietary restriction (DR) has been shown to slow the incidence of age-associated cardiovascular disease, metabolic disease, cancer and brain ageing in non-human primates and has been shown to improve a range of health indices in humans. While the idea that DR's ability to extend lifespan is often thought of as being universal, studies in a range of organisms, including yeast, mice and monkeys, suggest that this may not actually be the case. The precise reasons underlying these differential effects of DR on lifespan are currently unclear, but genetic background may be an important factor in how an individual responds to DR. Similarly, recent findings also suggest that the responsiveness of mice to specific genetic or pharmacological interventions that modulate ageing may again be influenced by genetic background. Consequently, while there is a clear driver to develop interventions to improve late-life health and vitality, understanding precisely how these act in response to particular genotypes is critical if we are to translate these findings to humans. We will consider of the role of genetic background in the efficacy of various lifespan interventions and discuss potential routes of utilising genetic heterogeneity to further understand how particular interventions modulate lifespan and healthspan.
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Affiliation(s)
- Lorna Mulvey
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medicine, Veterinary and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Amy Sinclair
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medicine, Veterinary and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medicine, Veterinary and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK.
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352
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Houédé N, Pourquier P. Targeting the genetic alterations of the PI3K-AKT-mTOR pathway: its potential use in the treatment of bladder cancers. Pharmacol Ther 2014; 145:1-18. [PMID: 24929024 DOI: 10.1016/j.pharmthera.2014.06.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 02/07/2023]
Abstract
Urothelial carcinoma of the bladder is the most frequent tumor of the urinary tract and represents the fifth cause of death by cancer worldwide. The current first line chemotherapy is a combination of cisplatin and gemcitabine with median survival not exceeding 15months. Vinflunine is the only drug approved by EMEA as second-line treatment and few progresses have been made for the past 20years to increase the survival of metastatic patients, especially those who are not eligible for cisplatin-based regimen. The recent studies characterizing the genetic background of urothelial cancers of the bladder, revealed chromosomal alterations that are not seen at the same level in other types of cancers. This is especially the case for mutations of genes involved in the PI3K/AKT/mTOR signaling pathway that occupies a major place in the etiology of these tumors. Here, we describe the mutations leading to constitutive activation of the PI3K/AKT/mTOR pathway and discuss the potential use of the different classes of PI3K/AKT/mTOR inhibitors in the treatment of urothelial bladder cancers. Despite the recent pivotal study evidencing specific mutations of TSC1 in bladder cancer patients responding to everolimus and the encouraging results obtained with other derivatives than rapalogs, few clinical trials are ongoing in bladder cancers. Because of the genetic complexity of these tumors, the cross-talks of the PI3K/AKT/mTOR pathway with other pathways, and the small number of eligible patients, it will be of utmost importance to carefully choose the drugs or drug combinations to be further tested in the clinic.
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Affiliation(s)
- Nadine Houédé
- Service d'Oncologie Médicale, Centre Hospitalier Universitaire de Nîmes, France; INSERM U896, Institut de Recherche en Cancérologie de Montpellier & Université de Montpellier 1, France.
| | - Philippe Pourquier
- Service d'Oncologie Médicale, Centre Hospitalier Universitaire de Nîmes, France; INSERM U896, Institut de Recherche en Cancérologie de Montpellier & Université de Montpellier 1, France
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353
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Nassif M, Valenzuela V, Rojas-Rivera D, Vidal R, Matus S, Castillo K, Fuentealba Y, Kroemer G, Levine B, Hetz C. Pathogenic role of BECN1/Beclin 1 in the development of amyotrophic lateral sclerosis. Autophagy 2014; 10:1256-71. [PMID: 24905722 DOI: 10.4161/auto.28784] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pharmacological activation of autophagy is becoming an attractive strategy to induce the selective degradation of aggregate-prone proteins. Recent evidence also suggests that autophagy impairment may underlie the pathogenesis of several neurodegenerative diseases. Mutations in the gene encoding SOD1 (superoxide disumutase 1) trigger familial amyotrophic lateral sclerosis (ALS), inducing its misfolding and aggregation and the progressive loss of motoneurons. It is still under debate whether autophagy has a protective or detrimental role in ALS. Here we evaluate the impact of BECN1/Beclin 1, an essential autophagy regulator, in ALS. BECN1 levels were upregulated in both cells and animals expressing mutant SOD1. To evaluate the impact of BECN1 to the pathogenesis of ALS in vivo, we generated mutant SOD1 transgenic mice heterozygous for Becn1. We observed an unexpected increase in life span of mutant SOD1 transgenic mice haploinsufficient for Becn1 compared with littermate control animals. These effects were accompanied by enhanced accumulation of SQSTM1/p62 and reduced levels of LC3-II, and an altered equilibrium between monomeric and oligomeric mutant SOD1 species in the spinal cord. At the molecular level, we detected an abnormal interaction of mutant SOD1 with the BECN1-BCL2L1 complex that may impact autophagy stimulation. Our data support a dual role of BECN1 in ALS and depict a complex scenario in terms of predicting the effects of manipulating autophagy in a disease context.
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Affiliation(s)
- Melissa Nassif
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Vicente Valenzuela
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Diego Rojas-Rivera
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - René Vidal
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Neurounion Biomedical Foundation; Santiago, Chile
| | - Soledad Matus
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Neurounion Biomedical Foundation; Santiago, Chile
| | - Karen Castillo
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Yerko Fuentealba
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Guido Kroemer
- INSERM U848; Villejuif, France; Metabolomics and Cell Biology Platforms; Institut Gustave Roussy; Villejuif, France; Equipe 11 labellisée par la Ligue contre le Cancer; Centre de Recherche des Cordeliers; Paris, France; Pôle de Biologie; Hôpital Européen Georges Pompidou; Paris, France; Université Paris Descartes; Sorbonne Paris Cité; Paris, France
| | - Beth Levine
- Department of Internal Medicine and Howard Hughes Medical Institute; UT Southwestern Medical Center; Dallas, TX USA
| | - Claudio Hetz
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Neurounion Biomedical Foundation; Santiago, Chile; Department of Immunology and Infectious Diseases; Harvard School of Public Health; Boston, MA USA
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354
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Kennedy BK, Pennypacker JK. Drugs that modulate aging: the promising yet difficult path ahead. Transl Res 2014; 163:456-65. [PMID: 24316383 PMCID: PMC4004650 DOI: 10.1016/j.trsl.2013.11.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 11/07/2013] [Accepted: 11/12/2013] [Indexed: 12/12/2022]
Abstract
Once a backwater in medical sciences, aging research has emerged and now threatens to take the forefront. This dramatic change of stature is driven from 3 major events. First and foremost, the world is rapidly getting old. Never before have we lived in a demographic environment like today, and the trends will continue such that 20% percent of the global population of 9 billion will be over the age of 60 by 2050. Given current trends of sharply increasing chronic disease incidence, economic disaster from the impending silver tsunami may be ahead. A second major driver on the rise is the dramatic progress that aging research has made using invertebrate models such as worms, flies, and yeast. Genetic approaches using these organisms have led to hundreds of aging genes and, perhaps surprisingly, strong evidence of evolutionary conservation among longevity pathways between disparate species, including mammals. Current studies suggest that this conservation may extend to humans. Finally, small molecules such as rapamycin and resveratrol have been identified that slow aging in model organisms, although only rapamycin to date impacts longevity in mice. The potential now exists to delay human aging, whether it is through known classes of small molecules or a plethora of emerging ones. But how can a drug that slows aging become approved and make it to market when aging is not defined as a disease. Here, we discuss the strategies to translate discoveries from aging research into drugs. Will aging research lead to novel therapies toward chronic disease, prevention of disease or be targeted directly at extending lifespan?
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355
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Altman JK, Szilard A, Goussetis DJ, Sassano A, Colamonici M, Gounaris E, Frankfurt O, Giles FJ, Eklund EA, Beauchamp EM, Platanias LC. Autophagy is a survival mechanism of acute myelogenous leukemia precursors during dual mTORC2/mTORC1 targeting. Clin Cancer Res 2014; 20:2400-9. [PMID: 24610825 DOI: 10.1158/1078-0432.ccr-13-3218] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE To examine whether induction of autophagy is a mechanism of leukemic cell resistance to dual mTORC1/mTORC2 inhibitors in acute myelogenous leukemia (AML) leukemic progenitors. EXPERIMENTAL DESIGN Combinations of different experimental approaches were used to assess induction of autophagy, including immunoblotting to detect effects on LC3II and p62/SQTM1 expression and on ULK1 phosphorylation, immunofluorescence, and electron microscopy. Functional responses were assessed using cell viability and apoptosis assays, and clonogenic leukemic progenitor assays in methylcellulose. RESULTS We provide evidence that treatment of AML cells with catalytic mTOR inhibitors results in induction of autophagy, which acts as a regulatory mechanism to promote leukemic cell survival. Such induction of autophagy by dual mTORC1/mTORC2 inhibitors partially protects primitive leukemic precursors from the inhibitory effects of such agents and limits their activities. Simultaneous blockade of the autophagic process using chloroquine or by knockdown of ULK1 results in enhanced antileukemic responses. CONCLUSIONS Dual targeting of mTORC2 and mTORC1 results in induction of autophagy in AML cells. Combinations of catalytic mTOR targeting agents and autophagy inhibitors may provide a unique approach to target primitive leukemic precursors in AML.
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Affiliation(s)
- Jessica K Altman
- Authors' Affiliations: Robert H. Lurie Comprehensive Cancer Center of Northwestern University; Division of Hematology/Oncology, Department of Medicine; Department of Radiology, Northwestern University, Feinberg School of Medicine; and Division of Hematology-Oncology, Department of Medicine, Jesse Brown VA Medical Center, Chicago, Illinois
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356
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Abstract
The mammalian target of rapamycin (mTOR) signaling pathway is a master regulator of cell growth and metabolism. Deregulation of the mTOR pathway has been implicated in a number of human diseases such as cancer, diabetes, obesity, neurological diseases, and genetic disorders. Rapamycin, a specific inhibitor of mTOR, has been shown to be useful in the treatment of certain diseases. Here we discuss its mechanism of action and highlight recent findings regarding the effects and limitations of rapamycin monotherapy and the potential utility of combination therapy with rapamycin.
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Affiliation(s)
- Jing Li
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Sang Gyun Kim
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - John Blenis
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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357
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Darzynkiewicz Z, Zhao H, Halicka HD, Li J, Lee YS, Hsieh TC, Wu JM. In search of antiaging modalities: evaluation of mTOR- and ROS/DNA damage-signaling by cytometry. Cytometry A 2014; 85:386-99. [PMID: 24677687 DOI: 10.1002/cyto.a.22452] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/06/2014] [Accepted: 06/02/2014] [Indexed: 12/31/2022]
Abstract
This review presents the evidence in support of the IGF-1/mTOR/S6K1 signaling as the primary factor contributing to aging and cellular senescence. Reviewed are also specific interactions between mTOR/S6K1 and ROS-DNA damage signaling pathways. Outlined are critical sites along these pathways, including autophagy, as targets for potential antiaging (gero-suppressive) and/or chemopreventive agents. Presented are applications of flow- and laser scanning- cytometry utilizing phospho-specific Abs, to monitor activation along these pathways in response to the reported antiaging drugs rapamycin, metformin, berberine, resveratrol, vitamin D3, 2-deoxyglucose, and acetylsalicylic acid. Specifically, effectiveness of these agents to attenuate the level of constitutive mTOR signaling was tested by cytometry and confirmed by Western blotting through measuring phosphorylation of the mTOR-downstream targets including ribosomal protein S6. The ratiometric analysis of phosphorylated to total protein along the mTOR pathway offers a useful parameter reporting the effects of gero-suppressive agents. In parallel, their ability to suppress the level of constitutive DNA damage signaling induced by endogenous ROS was measured. While the primary target of each of these agents may be different the data obtained on several human cancer cell lines, WI-38 fibroblasts and normal lymphocytes suggest common downstream mechanism in which the decline in mTOR/S6K1 signaling and translation rate is coupled with a reduction of oxidative phosphorylation and ROS that leads to decreased oxidative DNA damage. The combined assessment of constitutive γH2AX expression, mitochondrial activity (ROS, ΔΨm), and mTOR signaling provides an adequate gamut of cell responses to test effectiveness of gero-suppressive agents. Described is also an in vitro model of induction of cellular senescence by persistent replication stress, its quantitative analysis by laser scanning cytometry, and application to detect the property of the studied agents to attenuate the induction of senescence. Discussed is cytometric analysis of cell size and heterogeneity of size as a potential biomarker used to asses gero-suppressive agents and longevity.
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Affiliation(s)
- Zbigniew Darzynkiewicz
- Brander Cancer Research Institute and Department of Pathology, New York Medical College, Valhalla, New York, 10595
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358
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Signaling pathways in the development of infantile hemangioma. J Hematol Oncol 2014; 7:13. [PMID: 24479731 PMCID: PMC3913963 DOI: 10.1186/1756-8722-7-13] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/28/2014] [Indexed: 02/05/2023] Open
Abstract
Infantile hemangioma (IH), which is the most common tumor in infants, is a benign vascular neoplasm resulting from the abnormal proliferation of endothelial cells and pericytes. For nearly a century, researchers have noted that IH exhibits diverse and often dramatic clinical behaviors. On the one hand, most lesions pose no threat or potential for complication and resolve spontaneously without concern in most children with IH. On the other hand, approximately 10% of IHs are destructive, disfiguring and even vision- or life-threatening. Recent studies have provided some insight into the pathogenesis of these vascular tumors, leading to a better understanding of the biological features of IH and, in particular, indicating that during hemangioma neovascularization, two main pathogenic mechanisms prevail, angiogenesis and vasculogenesis. Both mechanisms have been linked to alterations in several important cellular signaling pathways. These pathways are of interest from a therapeutic perspective because targeting them may help to reverse, delay or prevent hemangioma neovascularization. In this review, we explore some of the major pathways implicated in IH, including the VEGF/VEGFR, Notch, β-adrenergic, Tie2/angiopoietins, PI3K/AKT/mTOR, HIF-α-mediated and PDGF/PDGF-R-β pathways. We focus on the role of these pathways in the pathogenesis of IH, how they are altered and the consequences of these abnormalities. In addition, we review the latest preclinical and clinical data on the rationally designed targeted agents that are now being directed against some of these pathways.
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359
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Boyette LB, Tuan RS. Adult Stem Cells and Diseases of Aging. J Clin Med 2014; 3:88-134. [PMID: 24757526 PMCID: PMC3992297 DOI: 10.3390/jcm3010088] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 12/15/2013] [Accepted: 12/17/2013] [Indexed: 02/06/2023] Open
Abstract
Preservation of adult stem cells pools is critical for maintaining tissue homeostasis into old age. Exhaustion of adult stem cell pools as a result of deranged metabolic signaling, premature senescence as a response to oncogenic insults to the somatic genome, and other causes contribute to tissue degeneration with age. Both progeria, an extreme example of early-onset aging, and heritable longevity have provided avenues to study regulation of the aging program and its impact on adult stem cell compartments. In this review, we discuss recent findings concerning the effects of aging on stem cells, contributions of stem cells to age-related pathologies, examples of signaling pathways at work in these processes, and lessons about cellular aging gleaned from the development and refinement of cellular reprogramming technologies. We highlight emerging therapeutic approaches to manipulation of key signaling pathways corrupting or exhausting adult stem cells, as well as other approaches targeted at maintaining robust stem cell pools to extend not only lifespan but healthspan.
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Affiliation(s)
- Lisa B Boyette
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA; ; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Rocky S Tuan
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA; ; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA ; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
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360
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Berry LM, Liu J, Colletti A, Krolikowski P, Zhao Z, Teffera Y. Species Difference in Glucuronidation Formation Kinetics with a Selective mTOR Inhibitor. Drug Metab Dispos 2014; 42:707-17. [DOI: 10.1124/dmd.113.054809] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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361
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Abstract
Dietary restriction (DR) has been shown to extend both median and maximum lifespan in a range of animals, although recent findings suggest that these effects are not universally enjoyed across all animals. In particular, the lifespan effect following DR in mice is highly strain-specific and there is little current evidence that DR induces a positive effect on all-cause mortality in non-human primates. However, the positive effects of DR on health appear to be highly conserved across the vast majority of species, including human subjects. Despite these effects on health, it is highly unlikely that DR will become a realistic or popular life choice for most human subjects given the level of restraint required. Consequently significant research is focusing on identifying compounds that will bestow the benefits of DR without the obligation to adhere to stringent reductions in daily food intake. Several such compounds, including rapamycin, metformin and resveratrol, have been identified as potential DR mimetics. Although these compounds show significant promise, there is a need to properly understand the mechanisms through which these drugs act. This review will discuss the importance in understanding the role that genetic background and heterogeneity play in mediating the lifespan and healthspan effects of DR. It will also provide an overview of the most promising current DR mimetics and their effects on healthy lifespan.
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362
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Guan P, Wang N. Mammalian target of rapamycin coordinates iron metabolism with iron-sulfur cluster assembly enzyme and tristetraprolin. Nutrition 2014; 30:968-74. [PMID: 24976419 DOI: 10.1016/j.nut.2013.12.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/13/2013] [Accepted: 12/15/2013] [Indexed: 01/07/2023]
Abstract
Both iron deficiency and excess are relatively common health concerns. Maintaining the body's levels of iron within precise boundaries is critical for cell functions. However, the difference between iron deficiency and overload is often a question of a scant few milligrams of iron. The mammalian target of rapamycin (mTOR), an atypical Ser/Thr protein kinase, is attracting significant amounts of interest due to its recently described role in iron homeostasis. Despite extensive study, a complete understanding of mTOR function has remained elusive. mTOR can form two multiprotein complexes that consist of mTOR complex 1 (mTORC1) and mTOR complex 2. Recent advances clearly demonstrate that mTORC1 can phosphorylate iron-sulfur cluster assembly enzyme ISCU and affect iron-sulfur clusters assembly. Moreover, mTOR is reported to control iron metabolism through modulation of tristetraprolin expression. It is now well appreciated that the hormonal hepcidin-ferroportin system and the cellular iron-responsive element/iron-regulatory protein regulatory network play important regulatory roles for systemic iron metabolism. Sustained ISCU protein levels enhanced by mTORC1 can inhibit iron-responsive element and iron-regulatory protein binding activities. In this study, hepcidin gene and protein expression in the livers of tristetraprolin knockout mice were dramatically reduced. Here, we highlight and summarize the current understanding of how mTOR pathways serve to modulate iron metabolism and homeostasis as the third iron-regulatory system.
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Affiliation(s)
- Peng Guan
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, Hebei Normal University, Hebei Province, China
| | - Na Wang
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, Hebei Normal University, Hebei Province, China; School of Basic Medical Sciences, Hebei University of Traditional Chinese Medicine, Hebei Province, China.
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363
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D’Alessandro A, Zolla L. Proteomics and metabolomics in cancer drug development. Expert Rev Proteomics 2014; 10:473-88. [DOI: 10.1586/14789450.2013.840440] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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364
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De Tata V. Age-related impairment of pancreatic Beta-cell function: pathophysiological and cellular mechanisms. Front Endocrinol (Lausanne) 2014; 5:138. [PMID: 25232350 PMCID: PMC4153315 DOI: 10.3389/fendo.2014.00138] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/07/2014] [Indexed: 12/13/2022] Open
Abstract
The incidence of type 2 diabetes significantly increases with age. The relevance of this association is dramatically magnified by the concomitant global aging of the population, but the underlying mechanisms remain to be fully elucidated. Here, some recent advances in this field are reviewed at the level of both the pathophysiology of glucose homeostasis and the cellular senescence of pancreatic islets. Overall, recent results highlight the crucial role of beta-cell dysfunction in the age-related impairment of pancreatic endocrine function and delineate the possibility of new original therapeutic interventions.
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Affiliation(s)
- Vincenzo De Tata
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- *Correspondence: Vincenzo De Tata, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma, 55 Scuola Medica, Pisa 56126, Italy e-mail:
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365
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Villa-Cuesta E, Fan F, Rand DM. Rapamycin reduces Drosophila longevity under low nutrition. ACTA ACUST UNITED AC 2014; 4:43-51. [PMID: 28593179 DOI: 10.9790/3013-0408043051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Rapamycin treatment is considered a pharmacological intervention with the potential to mimic the longevity benefits of dietary manipulations. However, how rapamycin interacts with nutrition is not fully understood. Here we studied the effect of rapamycin on the longevity of Drosophila under a range of dietary conditions. In diets low in nutrients, rapamycin reduced longevity in a dosage-dependent manner. This dosage effect requires some nutrients as rapamycin has no impact on survival under starvation conditions. Under a balanced diet of yeast and sugar, rapamycin had no repeatable beneficial effect on organismal longevity. These results show that the effect of rapamycin on longevity is sensitive to the nutritional environment and it can reduce lifespan when nutrients are limited.
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Affiliation(s)
| | - Frances Fan
- Department of Biology, Adelphi University. Garden City, NY 11530, USA
| | - David M Rand
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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366
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Callaghan B, Feldman E. The metabolic syndrome and neuropathy: therapeutic challenges and opportunities. Ann Neurol 2013; 74:397-403. [PMID: 23929529 DOI: 10.1002/ana.23986] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/25/2013] [Accepted: 07/29/2013] [Indexed: 12/11/2022]
Abstract
The metabolic syndrome and neuropathy are common conditions, especially in the elderly, that are associated with significant morbidity. Furthermore, the metabolic syndrome is reaching epidemic proportions across the world. Current evidence supports the association of the metabolic syndrome and its individual components with neuropathy. Several clinical trials have demonstrated that treating hyperglycemia, a component of the metabolic syndrome, has a significant effect on reducing the incidence of neuropathy in those with type 1 diabetes. However, glucose control has only a marginal effect on preventing neuropathy in those with type 2 diabetes, suggesting that other factors may be driving nerve injury in these patients. Emerging evidence supports the metabolic syndrome as including risk factors for neuropathy. Interventions exist for treatment of all of the metabolic syndrome components, but only glucose control has strong evidence to support its use and is widely employed. Our understanding of the biology of metabolic nerve injury has rapidly expanded over the past several years. Mechanisms of injury include fatty deposition in nerves, extracellular protein glycation, mitochondrial dysfunction, and oxidative stress. Additionally, the activation of counter-regulatory signaling pathways leads to chronic metabolic inflammation. Medications that target these signaling pathways are being used for a variety of diseases and are intriguing therapeutic agents for future neuropathy clinical trials. As we move forward, we need to expand our understanding of the association between the metabolic syndrome and neuropathy by addressing limitations of previous studies. Just as importantly, we must continue to investigate the pathophysiology of metabolically induced nerve injury.
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Affiliation(s)
- Brian Callaghan
- Department of Neurology, University of Michigan, Ann Arbor, MI
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367
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Mazzoccoli G, Tevy MF, Borghesan M, Delle Vergini MR, Vinciguerra M. Caloric restriction and aging stem cells: the stick and the carrot? Exp Gerontol 2013; 50:137-48. [PMID: 24211426 DOI: 10.1016/j.exger.2013.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/03/2013] [Accepted: 10/28/2013] [Indexed: 12/24/2022]
Abstract
Adult tissue stem cells have the ability to adjust to environmental changes and affect also the proliferation of neighboring cells, with important consequences on tissue maintenance and regeneration. Stem cell renewal and proliferation is strongly regulated during aging of the organism. Caloric restriction is the most powerful anti-aging strategy conserved throughout evolution in the animal kingdom. Recent studies relate the properties of caloric restriction to its ability in reprogramming stem-like cell states and in prolonging the capacity of stem cells to self-renew, proliferate, differentiate, and replace cells in several adult tissues. However this general paradigm presents with exceptions. The scope of this review is to highlight how caloric restriction impacts on diverse stem cell compartments and, by doing so, might differentially delay aging in the tissues of lower and higher organisms.
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Affiliation(s)
- Gianluigi Mazzoccoli
- Department of Medical Sciences, Division of Internal Medicine and Chronobiology Unit, IRCCS Scientific Institute and Regional General Hospital "Casa Sollievo della Sofferenza", S. Giovanni Rotondo, FG, Italy.
| | - Maria Florencia Tevy
- Genomics and Bioinformatics Centre, Major University of Santiago, Santiago, Chile
| | - Michela Borghesan
- Department of Medical Sciences, Division of Internal Medicine and Chronobiology Unit, IRCCS Scientific Institute and Regional General Hospital "Casa Sollievo della Sofferenza", S. Giovanni Rotondo, FG, Italy; University College London, Institute for Liver and Digestive Health, Division of Medicine, Royal Free Campus, London, United Kingdom
| | - Maria Rita Delle Vergini
- Department of Medical Sciences, Division of Internal Medicine and Chronobiology Unit, IRCCS Scientific Institute and Regional General Hospital "Casa Sollievo della Sofferenza", S. Giovanni Rotondo, FG, Italy
| | - Manlio Vinciguerra
- Department of Medical Sciences, Division of Internal Medicine and Chronobiology Unit, IRCCS Scientific Institute and Regional General Hospital "Casa Sollievo della Sofferenza", S. Giovanni Rotondo, FG, Italy; Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy; University College London, Institute for Liver and Digestive Health, Division of Medicine, Royal Free Campus, London, United Kingdom.
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368
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Ye L, Widlund AL, Sims CA, Lamming DW, Guan Y, Davis JG, Sabatini DM, Harrison DE, Vang O, Baur JA. Rapamycin doses sufficient to extend lifespan do not compromise muscle mitochondrial content or endurance. Aging (Albany NY) 2013; 5:539-50. [PMID: 23929887 PMCID: PMC3765582 DOI: 10.18632/aging.100576] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rapamycin extends lifespan in mice, but can have a number of undesirable effects that may ultimately limit its utility in humans. The canonical target of rapamycin, and the one thought to account for its effects on lifespan, is the mammalian/mechanistic target of rapamycin, complex 1 (mTORC1). We have previously shown that at least some of the detrimental side effects of rapamycin are due to "off target" disruption of mTORC2, suggesting they could be avoided by more specific targeting of mTORC1. However, mTORC1 inhibitionper se can reduce the mRNA expression of mitochondrial genes and compromise the function of mitochondria in cultured muscle cells, implying that defects in bioenergetics might be an unavoidable consequence of targeting mTORC1 in vivo. Therefore, we tested whether rapamycin, at the same doses used to extend lifespan, affects mitochondrial function in skeletal muscle. While mitochondrial transcripts were decreased, particularly in the highly oxidative soleus muscle, we found no consistent change in mitochondrial DNA or protein levels. In agreement with the lack of change in mitochondrial components, rapamycin-treated mice had endurance equivalent to that of untreated controls, and isolated, permeabilized muscle fibers displayed similar rates of oxygen consumption. We conclude that the doses of rapamycin required to extend life do not cause overt mitochondrial dysfunction in skeletal muscle.
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Affiliation(s)
- Lan Ye
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
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369
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Hartman NW, Lin TV, Zhang L, Paquelet GE, Feliciano DM, Bordey A. mTORC1 targets the translational repressor 4E-BP2, but not S6 kinase 1/2, to regulate neural stem cell self-renewal in vivo. Cell Rep 2013; 5:433-44. [PMID: 24139800 DOI: 10.1016/j.celrep.2013.09.017] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/14/2013] [Accepted: 09/11/2013] [Indexed: 12/21/2022] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) integrates signals important for cell growth, and its dysregulation in neural stem cells (NSCs) is implicated in several neurological disorders associated with abnormal neurogenesis and brain size. However, the function of mTORC1 on NSC self-renewal and the downstream regulatory mechanisms are ill defined. Here, we found that genetically decreasing mTORC1 activity in neonatal NSCs prevented their differentiation, resulting in reduced lineage expansion and aborted neuron production. Constitutive activation of the translational repressor 4E-BP1, which blocked cap-dependent translation, had similar effects and prevented hyperactive mTORC1 induction of NSC differentiation and promoted self-renewal. Although 4E-BP2 knockdown promoted NSC differentiation, p70 S6 kinase 1 and 2 (S6K1/S6K2) knockdown did not affect NSC differentiation but reduced NSC soma size and prevented hyperactive mTORC1-induced increase in soma size. These data demonstrate a crucial role of mTORC1 and 4E-BP for switching on and off cap-dependent translation in NSC differentiation.
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Affiliation(s)
- Nathaniel W Hartman
- Departments of Neurosurgery, and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8082, USA
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370
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Sherman MY, Qian SB. Less is more: improving proteostasis by translation slow down. Trends Biochem Sci 2013; 38:585-91. [PMID: 24126073 DOI: 10.1016/j.tibs.2013.09.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/04/2013] [Accepted: 09/10/2013] [Indexed: 11/29/2022]
Abstract
Protein homeostasis, or proteostasis, refers to a proper balance between synthesis, maturation, and degradation of cellular proteins. A growing body of evidence suggests that the ribosome serves as a hub for co-translational folding, chaperone interaction, degradation, and stress response. Accordingly, in addition to the chaperone network and proteasome system, the ribosome has emerged as a major factor in protein homeostasis. Recent work revealed that high rates of elongation of translation negatively affect both the fidelity of translation and the co-translational folding of nascent polypeptides. Accordingly, by slowing down translation one can significantly improve protein folding. In this review, we discuss how to target translational processes to improve proteostasis and implications in treating protein misfolding diseases.
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Affiliation(s)
- Michael Y Sherman
- Department of Biochemistry, Boston University Medical School, Boston, MA 02118, USA.
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371
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Abstract
The mechanistic target of rapamycin (mTOR) signaling pathway regulates many fundamental metabolic and physiological processes, including lipid metabolism. We explore recent findings on the role of mTOR in lipid homeostasis, with an emphasis on recent findings from in vivo models regarding the role of mTORC2 in lipolysis, lipogenesis, and adipogenesis.
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372
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Abstract
Biological functions of antibiotics are not limited to killing. The most likely function of antibiotics in natural microbial ecosystems is signaling. Does this signaling function of antibiotics also extend to the eukaryotic – in particular mammalian – cells? In this review, the host modulating properties of three classes of antibiotics (macrolides, tetracyclines, and β-lactams) will be briefly discussed. Antibiotics can be effective in treatment of a broad spectrum of diseases and pathological conditions other than those of infectious etiology and, in this capacity, may find widespread applications beyond the intended antimicrobial use. This use, however, should not compromise the primary function antibiotics are used for. The biological background for this inter-kingdom signaling is also discussed.
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Affiliation(s)
- Rustam I Aminov
- Faculty of Medical Sciences, University of the West Indies Kingston, Jamaica
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373
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Targeting the mTOR Signaling Network for Alzheimer’s Disease Therapy. Mol Neurobiol 2013; 49:120-35. [DOI: 10.1007/s12035-013-8505-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 07/01/2013] [Indexed: 12/29/2022]
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374
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Newgard CB, Sharpless NE. Coming of age: molecular drivers of aging and therapeutic opportunities. J Clin Invest 2013; 123:946-50. [PMID: 23454756 DOI: 10.1172/jci68833] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Aging is like the weather: everyone talks about it, but no one seems to do anything about it. We believe this may soon change, as an improved understanding of the molecular and genetic pathways underlying aging suggests it is possible to therapeutically target the aging process and increase health span. This Review series focuses on fundamental cellular mechanisms of aging and their relationship to human disease. These pathways include telomere dysfunction in cellular senescence and induction of the senescence-associated secretory phenotype (SASP) in systemic aging, sirtuin family regulation of metabolism and aging-associated diseases, mitochondrial metabolism in aging, the mechanistic target of rapamycin (mTOR) signaling pathway and the use of mTOR inhibitors to increase longevity, the progressive decline of the immune system with age, and aging-associated changes to pancreatic islet β cells that may contribute to diabetes. Together, these articles explore pathways affecting aging and possible interventional targets to slow or delay the onset of age-related pathologies.
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Affiliation(s)
- Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27704, USA.
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