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Lanza IR, Short DK, Short KR, Raghavakaimal S, Basu R, Joyner MJ, McConnell JP, Nair KS. Endurance exercise as a countermeasure for aging. Diabetes 2008; 57:2933-42. [PMID: 18716044 PMCID: PMC2570389 DOI: 10.2337/db08-0349] [Citation(s) in RCA: 402] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE We determined whether reduced insulin sensitivity, mitochondrial dysfunction, and other age-related dysfunctions are inevitable consequences of aging or secondary to physical inactivity. RESEARCH DESIGN AND METHODS Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp and ATP production in mitochondria isolated from vastus lateralis biopsies of 42 healthy sedentary and endurance-trained young (18-30 years old) and older (59-76 years old) subjects. Expression of proteins involved in fuel metabolism was measured by mass spectrometry. Citrate synthase activity, mitochondrial DNA (mtDNA) abundance, and expression of nuclear-encoded transcription factors for mitochondrial biogenesis were measured. SIRT3, a mitochondrial sirtuin linked to lifespan-enhancing effects of caloric restriction, was measured by immunoblot. RESULTS Insulin-induced glucose disposal and suppression of endogenous glucose production were higher in the trained young and older subjects, but no age effect was noted. Age-related decline in mitochondrial oxidative capacity was absent in endurance-trained individuals. Although endurance-trained individuals exhibited higher expression of mitochondrial proteins, mtDNA, and mitochondrial transcription factors, there were persisting effects of age. SIRT3 expression was lower with age in sedentary but equally elevated regardless of age in endurance-trained individuals. CONCLUSIONS The results demonstrate that reduced insulin sensitivity is likely related to changes in adiposity and to physical inactivity rather than being an inevitable consequence of aging. The results also show that regular endurance exercise partly normalizes age-related mitochondrial dysfunction, although there are persisting effects of age on mtDNA abundance and expression of nuclear transcription factors and mitochondrial protein. Furthermore, exercise may promote longevity through pathways common to effects of caloric restriction.
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Affiliation(s)
- Ian R Lanza
- Division of Endocrinology, Endocrinology Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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102
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Autiero I, Costantini S, Colonna G. Human sirt-1: molecular modeling and structure-function relationships of an unordered protein. PLoS One 2008; 4:e7350. [PMID: 19806227 PMCID: PMC2753774 DOI: 10.1371/journal.pone.0007350] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2009] [Accepted: 09/14/2009] [Indexed: 12/02/2022] Open
Abstract
Background Sirt-1 is a NAD+-dependent nuclear deacetylase of 747 residues that in mammals is involved in various important metabolic pathways, such as glucose metabolism and insulin secretion, and often works on many different metabolic substrates as a multifunctional protein. Sirt-1 down-regulates p53 activity, rising lifespan, and cell survival; it also deacetylases peroxisome proliferator-activated receptor-gamma (PPAR-γ) and its coactivator 1 alpha (PGC-1α), promoting lipid mobilization, positively regulating insulin secretion, and increasing mitochondrial dimension and number. Therefore, it has been implicated in diseases such as diabetes and the metabolic syndrome and, also, in the mechanisms of longevity induced by calorie restriction. Its whole structure is not yet experimentally determined and the structural features of its allosteric site are unknown, and no information is known about the structural changes determined by the binding of its allosteric effectors. Methodology In this study, we modelled the whole three-dimensional structure of Sirt-1 and that of its endogenous activator, the nuclear protein AROS. Moreover, we modelled the Sirt-1/AROS complex in order to study the structural basis of its activation and regulation. Conclusions Amazingly, the structural data show that Sirt-1 is an unordered protein with a globular core and two large unordered structural regions at both termini, which play an important role in the protein-protein interaction. Moreover, we have found on Sirt-1 a conserved pharmacophore pocket of which we have discussed the implication.
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Affiliation(s)
- Ida Autiero
- CRISCEB (Interdepartmental Research Center for Computational and Biotechnological Sciences) Second University of Naples, Naples, Italy
| | - Susan Costantini
- CRISCEB (Interdepartmental Research Center for Computational and Biotechnological Sciences) Second University of Naples, Naples, Italy
- CROM (Oncology Research Centre of Mercogliano) “Fiorentino Lo Vuolo”, Mercogliano, Italy
- Department of Biochemistry and Biophysics, Second University of Naples, Naples, Italy
- * E-mail:
| | - Giovanni Colonna
- CRISCEB (Interdepartmental Research Center for Computational and Biotechnological Sciences) Second University of Naples, Naples, Italy
- Department of Biochemistry and Biophysics, Second University of Naples, Naples, Italy
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103
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Compounds that confer thermal stress resistance and extended lifespan. Exp Gerontol 2008; 43:882-91. [PMID: 18755260 DOI: 10.1016/j.exger.2008.08.049] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 08/21/2008] [Accepted: 08/21/2008] [Indexed: 02/07/2023]
Abstract
The observation that long-lived and relatively healthy animals can be obtained by simple genetic manipulation prompts the search for chemical compounds that have similar effects. Since aging is the most important risk factor for many socially and economically important diseases, the discovery of a wide range of chemical modulators of aging in model organisms could prompt new strategies for attacking age-related disease such as diabetes, cancer and neurodegenerative disorders [Collins, J.J., Evason, K., Kornfeld, K., 2006. Pharmacology of delayed aging and extended lifespan of Caenorhabditis elegans. Exp. Gerontol.; Floyd, R.A., 2006. Nitrones as therapeutics in age-related diseases. Aging Cell 5, 51-57; Gill, M.S., 2006. Endocrine targets for pharmacological intervention in aging in Caenorhabditis elegans. Aging Cell 5, 23-30; Hefti, F.F., Bales, R., 2006. Regulatory issues in aging pharmacology. Aging Cell 5, 3-8]. Resistance to multiple types of stress is a common trait in long-lived genetic variants of a number of species; therefore, we have tested compounds that act as stress response mimetics. We have focused on compounds with antioxidant properties and identified those that confer thermal stress resistance in the nematode Caenorhabditis elegans. Some of these compounds (lipoic acid, propyl gallate, trolox and taxifolin) also extend the normal lifespan of this simple invertebrate, consistent with the general model that enhanced stress resistance slows aging.
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104
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Rattan SIS, Fernandes RA, Demirovic D, Dymek B, Lima CF. Heat stress and hormetin-induced hormesis in human cells: effects on aging, wound healing, angiogenesis, and differentiation. Dose Response 2008; 7:90-103. [PMID: 19343114 DOI: 10.2203/dose-response.08-014.rattan] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Accumulation of molecular damage and increased molecular heterogeneity are hallmarks of cellular aging. Mild stress-induced hormesis can be an effective way for reducing the accumulation of molecular damage, and thus slowing down aging from within. We have shown that repeated mild heat stress (RMHS) has anti-aging effects on growth and various other cellular and biochemical characteristics of normal human skin fibroblasts and keratinocytes undergoing aging in vitro. RMHS given to human cells increased the basal levels of various chaperones, reduced the accumulation of damaged proteins, stimulated proteasomal activities, increased the cellular resistance to other stresses, enhanced the levels of various antioxidant enzymes, enhanced the activity and amounts of sodium-potassium pump, and increased the phosphorylation-mediated activities of various stress kinases. We have now observed novel hormetic effects of mild heat stress on improving the wound healing capacity of skin fibroblasts and on enhancing the angiogenic ability of endothelial cells. We have also tested potential hormetins, such as curcumin and rosmarinic acid in bringing about their beneficial effects in human cells by inducing stress response pathways involving heat shock proteins and hemeoxygenase HO-1. These data further support the view that mild stress-induced hormesis can be applied for the modulation, intervention and prevention of aging and age-related impairments.
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Affiliation(s)
- Suresh I S Rattan
- Laboratory of Cellular Ageing, Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, Aarhus-C, Denmark.
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105
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Epi-drugs to fight cancer: from chemistry to cancer treatment, the road ahead. Int J Biochem Cell Biol 2008; 41:199-213. [PMID: 18790076 DOI: 10.1016/j.biocel.2008.08.020] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 08/08/2008] [Accepted: 08/08/2008] [Indexed: 12/16/2022]
Abstract
In addition to genetic events, a variety of epigenetic events have been widely reported to contribute to the onset of many diseases including cancer. DNA methylation and histone modifications (such as acetylation, methylation, sumoylation, and phosphorylation) involving chromatin remodelling are among the most studied epigenetic mechanisms for regulation of gene expression leading, when altered, to some diseases. Epigenetic therapy tries to reverse the aberrations followed to the disruption of the balance of the epigenetic signalling ways through the use of both natural compounds and synthetic molecules, active on specific epi-targets. Such epi-drugs are, for example, inhibitors of DNA methyltransferases, histone deacetylases, histone acetyltransferases, histone methyltransferases, and histone demethylases. In this review we will focus on the chemical aspects of such molecules, joined to their effective (or potential) application in cancer therapy.
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106
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Tikoo K, Singh K, Kabra D, Sharma V, Gaikwad A. Change in histone H3 phosphorylation, MAP kinase p38, SIR 2 and p53 expression by resveratrol in preventing streptozotocin induced type I diabetic nephropathy. Free Radic Res 2008; 42:397-404. [PMID: 18404539 DOI: 10.1080/10715760801998646] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Resveratrol has been reported to have a wide variety of biological effects. However, little is known regarding its role on phosphorylation of histone H3, MAP kinase p38, SIR2 and p53 in type I diabetic nephropathy (DN). Hence, the present study was undertaken to examine changes in the above said parameters by resveratrol treatment. Male Sprague-Dawley rats were rendered diabetic using a single dose of streptozotocin (55 mg/kg, i.p.). DN was assessed by measurements of blood urea nitrogen and creatinine levels. Phosphorylation of histone H3, SIR2, p53 and MAP kinase p38 expression were examined by western blotting. This study reports that treatment of resveratrol prevents the decrease in the expression of SIR2 in diabetic kidney. It also prevents increase in p38, p53 expression and dephosphorylation of histone H3 in diabetic kidney. This is the first report which suggests that protection against development of diabetic nephropathy by resveratrol treatment involves change in phosphorylation of histone H3, expression of Sir-2, p53 and p38 in diabetic kidney.
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Affiliation(s)
- Kulbhushan Tikoo
- Laboratory of Chromatin Biology, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Punjab, India.
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107
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Mattson MP. Hormesis and disease resistance: activation of cellular stress response pathways. Hum Exp Toxicol 2008; 27:155-62. [PMID: 18480142 DOI: 10.1177/0960327107083417] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The survival of all organisms depends upon their ability to overcome stressful conditions, an ability that involves adaptive changes in cells and molecules. Findings from studies of animal models and human populations suggest that hormesis (beneficial effects of low levels of stress) is an effective means of protecting against many different diseases including diabetes, cardiovascular disease, cancers and neurodegenerative disorders. Such stress resistance mechanisms can be bolstered by diverse environmental factors including exercise, dietary restriction, cognitive stimulation and exposure to low levels of toxins. Some commonly used vitamins and dietary supplements may also induce beneficial stress responses. Several interrelated cellular signaling molecules are involved in the process of hormesis. Examples include the gases oxygen, carbon monoxide and nitric oxide, the neurotransmitter glutamate, the calcium ion and tumor necrosis factor. In each case low levels of these signaling molecules are beneficial and protect against disease, whereas high levels can cause the dysfunction and/or death of cells. The cellular and molecular mechanisms of hormesis are being revealed and include activation of growth factor signaling pathways, protein chaperones, cell survival genes and enzymes called sirtuins. Knowledge of hormesis mechanisms is leading to novel approaches for preventing and treating a range of human diseases.
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Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA.
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108
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Rattan SI. Principles and practice of hormetic treatment of aging and age-related diseases. Hum Exp Toxicol 2008; 27:151-4. [PMID: 18480141 DOI: 10.1177/0960327107083409] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aging is characterized by stochastic accumulation of molecular damage, progressive failure of maintenance and repair, and consequent onset of age-related diseases. Applying hormesis in aging research and therapy is based on the principle of stimulation of maintenance and repair pathways by repeated exposure to mild stress. Studies on the beneficial biological effects of repeated mild heat shock on human cells in culture, and other studies on the anti-aging and life-prolonging effects of proxidants, hypergravity, irradiation and ethanol on cells and organisms suggest that hormesis as an antiaging and gerontomodulatory approach has a promising future. Its clinical applications include prevention and treatment of diabetes, cataract, osteoporosis, dementia and some cancers.
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Affiliation(s)
- Suresh Is Rattan
- Laboratory of Cellular Ageing, Department of Molecular Biology, University of Aarhus, Aarhus-C, Denmark.
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109
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Ohlsson AB, Landberg T, Berglund T, Greger M. Increased metal tolerance in Salix by nicotinamide and nicotinic acid. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:655-664. [PMID: 18524611 DOI: 10.1016/j.plaphy.2008.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Indexed: 05/26/2023]
Abstract
We have earlier shown that nicotinamide (NIC) and nicotinic acid (NiA) can induce defence-related metabolism in plant cells; e.g. increase the level of glutathione. Here we investigated if NIC and NiA could increase the metal tolerance in metal sensitive clones of Salix viminalis and whether this would be mediated via increased glutathione level. Salix clones, sensitive or tolerant to zinc (Zn), copper (Cu) and cadmium (Cd) were grown in the presence of heavy metals (Cd, Cu or Zn) or NIC and NiA as well as in combination. In addition, the influence of N-acetyl-cystein (NAC) and l-2-oxothiazolidine 4-carboxylate (OTC), stimulators of reduced glutathione (GSH) biosynthesis, and the glutathione biosynthesis inhibitor buthionine sulfoximine (BSO) was analysed. Tolerance was measured as effects on root and shoot dry weight, and the glutathione and metal concentrations in the tissues were analysed. Results showed that NIC and NiA decreased the toxic effects of Cd, Cu and Zn on growth significantly in sensitive clones, but also to some extent in tolerant clones. However, the glutathione level and metal concentration did not change by NIC or NiA addition. Treatment with NAC, OTC or BSO did not per se influence the sensitivity to Cd, although the glutathione level increased in the presence of NAC and OTC and decreased in response to BSO. The results suggest that NIC and NiA increased the defence against heavy metals but not via glutathione formation per se.
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Affiliation(s)
- Anna B Ohlsson
- Department of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - Tommy Landberg
- Department of Botany, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Torkel Berglund
- Department of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - Maria Greger
- Department of Botany, Stockholm University, SE-106 91 Stockholm, Sweden
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110
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Mitochondrial medicine for aging and neurodegenerative diseases. Neuromolecular Med 2008; 10:291-315. [PMID: 18566920 DOI: 10.1007/s12017-008-8044-z] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 05/22/2008] [Indexed: 12/22/2022]
Abstract
Mitochondria are key cytoplasmic organelles, responsible for generating cellular energy, regulating intracellular calcium levels, altering the reduction-oxidation potential of cells, and regulating cell death. Increasing evidence suggests that mitochondria play a central role in aging and in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and Freidriech ataxia. Further, several lines of evidence suggest that mitochondrial dysfunction is an early event in most late-onset neurodegenerative diseases. Biochemical and animal model studies of inherited neurodegenerative diseases have revealed that mutant proteins of these diseases are associated with mitochondria. Mutant proteins are reported to block the transport of nuclear-encoded mitochondrial proteins to mitochondria, interact with mitochondrial proteins and disrupt the electron transport chain, induce free radicals, cause mitochondrial dysfunction, and, ultimately, damage neurons. This article discusses critical issues of mitochondria causing dysfunction in aging and neurodegenerative diseases, and discusses the potential of developing mitochondrial medicine, particularly mitochondrially targeted antioxidants, to treat aging and neurodegenerative diseases.
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111
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Bavaresco L, Vezzulli S, Civardi S, Gatti M, Battilani P, Pietri A, Ferrari F. Effect of lime-induced leaf chlorosis on ochratoxin A, trans-resveratrol, and epsilon-viniferin production in grapevine (Vitis vinifera L.) berries infected by Aspergillus carbonarius. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:2085-2089. [PMID: 18290620 DOI: 10.1021/jf073456+] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Berries of Vitis vinifera L. cv. Merlot, grown on a neutral or calcareous soil, were infected, at phenological phases of veraison and ripening, by a conidial suspension of Aspergillus carbonarius to control ochratoxin A production and trans-resveratrol- and epsilon-viniferin-induced synthesis as affected by the soil lime content. Chlorosis occurrence was evaluated by a visual rating scale at veraison, and the leaves from vines growing on the calcareous soil showed the typical yellowing, whereas those grown on the neutral soil were dark green. Berry mineral element yield was recorded at veraison and ripening. Infection symptoms on berries were more severe at ripening in bunches collected from vines grown in calcareous soil. Ochratoxin A concentration increased at phenological phase of veraison in berries harvested from vines cultivated in calcareous soil. A. carbonarius enhanced trans-resveratrol and epsilon-viniferin production in infected berries more than in the control samples. Moreover, at veraison their concentration in the berries collected from vines grown in calcareous soil was greater than that recorded from berries collected from vines grown in the neutral soil. The lowest symptom severity was observed on berries containing the highest copper concentration.
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Affiliation(s)
- Luigi Bavaresco
- Istituto di Frutti-Viticoltura, Università Cattolica del Sacro Cuore, Piacenza, Italy.
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112
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Abstract
Polyphenols such as resveratrol and quercetin, which are produced by stressed plants, activate sirtuin enzymes and extend the lifespan of fungi and animals, ostensibly by mimicking the beneficial effects of caloric restriction. This observation raises an interesting question: Why should foreign molecules that are non-nutritive and seemingly unrelated to any endogenous molecule modulate the same biochemical pathways that mediate the response to an energy deficit? A possible explanation is that the sirtuin enzymes have evolved to respond to plant stress molecules as indicators of an impending deterioration of the environment. This idea has become known as the Xenohormesis Hypothesis, the name stemming from a combination of the prefix xeno-(for stranger) with hormesis (a protective response induced by mild stress). Here we review the evidence for xenohormesis in a broader context, taking into account the diverse spectrum of phytochemicals to which animals are exposed. We also consider alternative hypotheses that may explain some of the beneficial effects of plant-based foods. We suggest that xenohormesis, defined as an adaptive response in the physiology of an organism to molecular cues that are neither nutritive nor direct stressors, most likely occurs at some level. Whether this can fully or partially account for the beneficial effects of resveratrol and other phytochemicals remains to be seen. However, there is already sufficient cause to re-evaluate the relationship between complex organisms, including humans and their food.
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Affiliation(s)
- Joseph A Baur
- Department of Pathology, Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115
| | - David A Sinclair
- Department of Pathology, Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115
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113
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Putics A, Végh EM, Csermely P, Soti C. Resveratrol induces the heat-shock response and protects human cells from severe heat stress. Antioxid Redox Signal 2008; 10:65-75. [PMID: 17956190 DOI: 10.1089/ars.2007.1866] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Molecular chaperones play key roles in protein quality control, signal transduction, proliferation, and cell death, and confer cytoprotection and assure survival after environmental stress. The heat-shock response is implicated in a variety of conditions including ischemic diseases, infection and immunity, neurodegeneration, and aging. Physiologic and pharmacologic chaperone inducers were shown to be an efficient therapeutic approach in different acute and chronic diseases. Here we characterize resveratrol, a polyphenol from red wine, as an inducer of the heat-shock response. Resveratrol activated the heat-shock promoter and the expression of the major chaperone Hsp70 in cell lines and in human peripheral lymphocytes, comparable to moderate heat stress. This effect was not due to its antioxidant property, because 5 mM N-acetylcysteine was unable to activate the heat-shock response. Moreover, resveratrol failed to upregulate Grp78, and tunicamycin was unable to induce Hsp70, suggesting that the resveratrol-induced heat-shock response was not mediated by canonic endoplasmic reticulum stress. Resveratrol synergized with mild to moderate heat shock and conferred cytoprotection against severe heat stress. Our results reveal resveratrol as a chaperone inducer that may contribute to its pleiotropic effects in ameliorating stress and promoting longevity.
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Affiliation(s)
- Akos Putics
- Department of Medical Chemistry, Semmelweis University, Budapest, Hungary
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114
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Abstract
Hormesis is defined operationally as responses of cells or organisms to an exogenous or intrinsic factor (chemical, temperature, psychological challenge, etc.) in which the factor induces stimulatory or beneficial effects at low doses and inhibitory or adverse effects at high doses. The compendium of articles by Calabrese entitled "Neuroscience and Hormesis" provides a broad range of examples of neurobiological processes and responses to environmental factors that exhibit biphasic dose responses, the signature of hormesis. Nerve cell networks are the "first responders" to environmental challenges--they perceive the challenge and orchestrate coordinated adaptive responses that typically involve autonomic, neuroendocrine, and behavioral changes. In addition to direct adaptive responses of neurons to environmental stressors, cells subjected to a stressor produce and release molecules such as growth factors, cytokines, and hormones that alert adjacent and even distant cells to impending danger. The discoveries that some molecules (e.g., carbon monoxide and nitric oxide) and elements (e.g., selenium and iron) that are toxic at high doses play fundamental roles in cellular signaling or metabolism suggest that during evolution, organisms (and their nervous systems) co-opted environmental toxins and used them to their advantage. Neurons also respond adaptively to everyday stressors, including physical exercise, cognitive challenges, and dietary energy restriction, each of which activates pathways linked to the production of neurotrophic factors and cellular stress resistance proteins. The development of interventions that activate hormetic signaling pathways in neurons is a promising new approach for the preventation and treatment of a range of neurological disorders.
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Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224, USA.
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115
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Abstract
Hormesis in aging is represented by mild stress-induced stimulation of protective mechanisms in cells and organisms resulting in biologically beneficial effects. Single or multiple exposure to low doses of otherwise harmful agents, such as irradiation, food limitation, heat stress, hypergravity, reactive oxygen species and other free radicals have a variety of anti-aging and longevity-extending hormetic effects. Detailed molecular mechanisms that bring about the hormetic effects are being increasingly understood, and comprise a cascade of stress response and other pathways of maintenance and repair. Although the extent of immediate hormetic effects after exposure to a particular stress may only be moderate, the chain of events following initial hormesis leads to biologically amplified effects that are much larger, synergistic and pleiotropic. A consequence of hormetic amplification is an increase in the homeodynamic space of a living system in terms of increased defence capacity and reduced load of damaged macromolecules. Hormetic strengthening of the homeodynamic space provides wider margins for metabolic fluctuation, stress tolerance, adaptation and survival. Hormesis thus counter-balances the progressive shrinkage of the homeodynamic space, which is the ultimate cause of aging, diseases and death. Healthy aging may be achieved by hormesis through mild and periodic, but not severe or chronic, physical and mental challenges, and by the use of nutritional hormesis incorporating mild stress-inducing molecules called hormetins. The established scientific foundations of hormesis are ready to pave the way for new and effective approaches in aging research and intervention.
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Affiliation(s)
- Suresh I S Rattan
- Laboratory of Cellular Ageing, Department of Molecular Biology, University of Aarhus, Aarhus-C, Denmark.
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116
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Bordone L, Cohen D, Robinson A, Motta MC, van Veen E, Czopik A, Steele AD, Crowe H, Marmor S, Luo J, Gu W, Guarente L. SIRT1 transgenic mice show phenotypes resembling calorie restriction. Aging Cell 2007; 6:759-67. [PMID: 17877786 DOI: 10.1111/j.1474-9726.2007.00335.x] [Citation(s) in RCA: 520] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We generated mice that overexpress the sirtuin, SIRT1. Transgenic mice have been generated by knocking in SIRT1 cDNA into the beta-actin locus. Mice that are hemizygous for this transgene express normal levels of beta-actin and higher levels of SIRT1 protein in several tissues. Transgenic mice display some phenotypes similar to mice on a calorie-restricted diet: they are leaner than littermate controls; are more metabolically active; display reductions in blood cholesterol, adipokines, insulin and fasted glucose; and are more glucose tolerant. Furthermore, transgenic mice perform better on a rotarod challenge and also show a delay in reproduction. Our findings suggest that increased expression of SIRT1 in mice elicits beneficial phenotypes that may be relevant to human health and longevity.
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Affiliation(s)
- Laura Bordone
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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118
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Pletcher SD, Kabil H, Partridge L. Chemical Complexity and the Genetics of Aging. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2007; 38:299-326. [PMID: 25685107 PMCID: PMC4326673 DOI: 10.1146/annurev.ecolsys.38.091206.095634] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We examine how aging is impacted by various chemical challenges that organisms face and by the molecular mechanisms that have evolved to regulate lifespan in response to them. For example, environmental information, which is detected and processed through sensory systems, can modulate lifespan by providing information about the presence and quality of food as well as presence and density of conspecifics and predators. In addition, the diverse forms of molecular damage that result from constant exposure to damaging chemicals that are generated from the environment and from metabolism pose an informatic and energetic challenge for detoxification systems, which are important in ensuring longevity. Finally, systems of innate immunity are vital for recognizing and combating pathogens but are also seen as of increasing importance in causing the aging process. Integrating ideas of molecular mechanism with context derived from evolutionary considerations will lead to exciting new insights into the evolution of aging.
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Affiliation(s)
- Scott D. Pletcher
- Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
| | - Hadise Kabil
- Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
| | - Linda Partridge
- Center for Research on Ageing, University College London, Darwin Building, Gower Street, London, WC1E6BT
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119
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Kim D, Nguyen MD, Dobbin MM, Fischer A, Sananbenesi F, Rodgers JT, Delalle I, Baur JA, Sui G, Armour SM, Puigserver P, Sinclair DA, Tsai LH. SIRT1 deacetylase protects against neurodegeneration in models for Alzheimer's disease and amyotrophic lateral sclerosis. EMBO J 2007; 26:3169-79. [PMID: 17581637 PMCID: PMC1914106 DOI: 10.1038/sj.emboj.7601758] [Citation(s) in RCA: 786] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 05/22/2007] [Indexed: 01/10/2023] Open
Abstract
A progressive loss of neurons with age underlies a variety of debilitating neurological disorders, including Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), yet few effective treatments are currently available. The SIR2 gene promotes longevity in a variety of organisms and may underlie the health benefits of caloric restriction, a diet that delays aging and neurodegeneration in mammals. Here, we report that a human homologue of SIR2, SIRT1, is upregulated in mouse models for AD, ALS and in primary neurons challenged with neurotoxic insults. In cell-based models for AD/tauopathies and ALS, SIRT1 and resveratrol, a SIRT1-activating molecule, both promote neuronal survival. In the inducible p25 transgenic mouse, a model of AD and tauopathies, resveratrol reduced neurodegeneration in the hippocampus, prevented learning impairment, and decreased the acetylation of the known SIRT1 substrates PGC-1alpha and p53. Furthermore, injection of SIRT1 lentivirus in the hippocampus of p25 transgenic mice conferred significant protection against neurodegeneration. Thus, SIRT1 constitutes a unique molecular link between aging and human neurodegenerative disorders and provides a promising avenue for therapeutic intervention.
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Affiliation(s)
- Dohoon Kim
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
- Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
| | - Minh Dang Nguyen
- Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - Matthew M Dobbin
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Andre Fischer
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Farahnaz Sananbenesi
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Joseph T Rodgers
- Dana Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Cell Biology, Johns Hopkins University School of Medicine, Boston, MA, USA
| | - Ivana Delalle
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Joseph A Baur
- Department of Pathology and Paul F Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA, USA
| | - Guangchao Sui
- Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - Sean M Armour
- Department of Pathology and Paul F Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA, USA
| | - Pere Puigserver
- Dana Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Cell Biology, Johns Hopkins University School of Medicine, Boston, MA, USA
| | - David A Sinclair
- Department of Pathology and Paul F Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA, USA
| | - Li-Huei Tsai
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
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120
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Jacobs DR, Andersen LF, Blomhoff R. Whole-grain consumption is associated with a reduced risk of noncardiovascular, noncancer death attributed to inflammatory diseases in the Iowa Women's Health Study. Am J Clin Nutr 2007; 85:1606-14. [PMID: 17556700 DOI: 10.1093/ajcn/85.6.1606] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND It has recently been shown that oxidative stress, infection, and inflammation are predominant pathophysiologic factors for several major diseases. OBJECTIVE We investigated the association of whole-grain intake with death attributed to noncardiovascular, noncancer inflammatory diseases. DESIGN Postmenopausal women (n = 41 836) aged 55-69 y at baseline in 1986 were followed for 17 y. After exclusions for cardiovascular disease, cancer, diabetes, colitis, and liver cirrhosis at baseline, 27 312 participants remained, of whom 5552 died during the 17 y. A proportional hazards regression model was adjusted for age, smoking, adiposity, education, physical activity, and other dietary factors. RESULTS Inflammation-related death was inversely associated with whole-grain intake. Compared with the hazard ratios in women who rarely or never ate whole-grain foods, the hazard ratio was 0.69 (95% CI: 0.57, 0.83) for those who consumed 4-7 servings/wk, 0.79 (0.66, 0.95) for 7.5-10.5 servings/wk, 0.64 (0.53, 0.79) for 11-18.5 servings/wk, and 0.66 (0.54, 0.81) for >or=19 servings/wk (P for trend = 0.01). Previously reported inverse associations of whole-grain intake with total and coronary heart disease mortality persisted after 17 y of follow-up. CONCLUSIONS The reduction in inflammatory mortality associated with habitual whole-grain intake was larger than that previously reported for coronary heart disease and diabetes. Because a variety of phytochemicals are found in whole grains that may directly or indirectly inhibit oxidative stress, and because oxidative stress is an inevitable consequence of inflammation, we suggest that oxidative stress reduction by constituents of whole grain is a likely mechanism for the protective effect.
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Affiliation(s)
- David R Jacobs
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
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121
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Gruber J, Tang SY, Halliwell B. Evidence for a trade-off between survival and fitness caused by resveratrol treatment of Caenorhabditis elegans. Ann N Y Acad Sci 2007; 1100:530-42. [PMID: 17460219 DOI: 10.1196/annals.1395.059] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Resveratrol is a naturally occurring polyphenolic compound commonly found in plant-derived products, including red wine. A large number of beneficial effects including anticarcinogenic action and protection from atherosclerotic disease have been attributed to resveratrol. Increased resveratrol intake has been suggested as an explanation for the beneficial effects of moderate red wine consumption. Resveratrol also consistently extends the mean and maximum life span in model organisms including nematode worms. It has been suggested that resveratrol exerts its life-span-extending effect through calorie restriction or hormesis mimetic effects. We have characterized the effect of resveratrol on stress resistance, developmental rate, growth, and fecundity in the nematode worm Caenorhabditis elegans in order to determine whether the beneficial effects of resveratrol on life span are associated with trade-offs in terms of early life fitness in nematodes. We find that resveratrol treatment increases stress resistance, specifically to oxidative stress, and causes a small but significant decrease in fecundity early in life without affecting overall fecundity. Resveratrol increased mean and maximum life span by delaying the onset of the exponential increase in mortality characterizing the "dying phase" in C. elegans, but did not affect the dying phase itself, suggesting that it did not act by directly affecting metabolism.
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Affiliation(s)
- Jan Gruber
- National University of Singapore University Hall, Lee Kong Chian Wing, UHL no. 05-02G, 21 Lower Kent Ridge Road, Singapore
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122
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Salvioli S, Sikora E, Cooper EL, Franceschi C. Curcumin in cell death processes: a challenge for CAM of age-related pathologies. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2007; 4:181-90. [PMID: 17549234 PMCID: PMC1876609 DOI: 10.1093/ecam/nem043] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Accepted: 03/24/2007] [Indexed: 12/28/2022]
Abstract
Curcumin, the yellow pigment from the rhizoma of Curcuma longa, is a widely studied phytochemical which has a variety of biological activities: anti-inflammatory and anti-oxidative. In this review we discuss the biological mechanisms and possible clinical effects of curcumin treatment on cancer therapy, and neurodegenerative diseases such as Alzheimer's Disease, with particular attention to the cell death processes induced by curcumin. Since oxidative stress and inflammation are major determinants of the aging process, we also argue that curcumin can have a more general effect that slows down the rate of aging. Finally, the effects of curcumin can be described as xenohormetic, since it activates a sort of stress response in mammalian cells.
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Affiliation(s)
- S Salvioli
- Department of Experimental Pathology and Centro Interdipartimentale "L. Galvani", University of Bologna, via S. Giacomo 12, 40126 Bologna, Italy
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124
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Abstract
Sirtuins are a family of NAD+-dependent protein deacetylases widely distributed in all phyla of life. Accumulating evidence indicates that sirtuins are important regulators of organism life span. In yeast, these unique enzymes regulate gene silencing by histone deacetylation and via formation of the novel compound 2'-O-acetyl-ADP-ribose. In multicellular organisms, sirtuins deacetylate histones and transcription factors that regulate stress, metabolism, and survival pathways. The chemical mechanism of sirtuins provides novel opportunities for signaling and metabolic regulation of protein deacetylation. The biological, chemical, and structural characteristics of these unusual enzymes are discussed in this review.
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Affiliation(s)
- Anthony A Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, New York, New York 10021, USA.
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125
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Kazantsev AG. Developing a neuroprotective therapy for Parkinson’s and Huntington’s diseases. Expert Opin Ther Pat 2007. [DOI: 10.1517/13543776.17.2.159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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126
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Yun AJ, Doux JD. Unhappy meal: How our need to detect stress may have shaped our preferences for taste. Med Hypotheses 2007; 69:746-51. [PMID: 17374557 DOI: 10.1016/j.mehy.2007.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2007] [Accepted: 02/02/2007] [Indexed: 11/20/2022]
Abstract
Conventional wisdom says that our preferences for particular tastes evolved to ensure an adequate instinctual intake of metabolic resources. Yet we discern scant taste in many vital dietary components, such as vitamins, minerals, co-factors, essential fatty acids and amino acids. We propose that taste preferences evolved to serve a secondary function--that of xenohormesis. Stress causes organisms to convert complex sugars to simple sugars, as seen during fruit ripening, and to increase the proportion of high-energy saturated fats relative to unsaturated fats, as seen among farmed livestock. The presence of dietary simple sugars, saturated fats, and salt within an organism may echo its stress experience--an experience assimilated by others when consumed. As each successive consumer in the food chain incorporates the stress phenotypes of its dietary components, cues for stress may accumulate in a game of "you-are-what-you-eat". Detection of environmental stress embedded in diet may promote adaptive phenotype remodeling such as caloric hoarding to contend with potential ecologic challenges. The phenotype remodeling may be the result of direct stress signaling properties of fats, sugars, and salt. Since food ecosystems typically exhibit seasonality in composition, early detection of cues of ecologic stress during autumn, such as dehydration, lowered ambient temperatures, and impending resource scarcity, likely confers advantages in fitness. Taste preferences may represent a form of "Darwinian rubbernecking. Much like paying attention to vignettes of violence and trauma, recognizing proxies of ecologic stress and adapting accordingly may yield fitness advantages. Many aspects of agricultural modernization may increase the level of stress embedded in the food chain, catering to pre-existing taste preferences in a form of illegitimate signaling. Globalization and technology have transformed the dietary experience of autumn--when the food chain undergoes stress and therefore tastes the best--into a year-round bacchanal. Instead of experiencing ecologic stress through their diet in a seasonal pattern, modern humans have become creatures of chronic stress. Many human conditions related to stress dysfunctions may partly arise from maladaptive consumption of stressed foods. We anticipate that low-stress and stress-free food may have therapeutic potential in the treatment of diseases and the promotion of health.
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Affiliation(s)
- Anthony J Yun
- Palo Alto Institute, 470 University Avenue, Palo Alto, CA 94301, USA
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127
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Marwah RS, Doux JD, Lee PY, Yun AJ. Is atherosclerosis a neurogenic phenomenon? Med Hypotheses 2007; 69:884-7. [PMID: 17400398 DOI: 10.1016/j.mehy.2007.01.066] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 01/21/2007] [Indexed: 11/23/2022]
Abstract
Identified risk factors for atherosclerosis include diet, age, gender, family history, stress, lifestyle, smoking, diabetes, dyslipidemias, hypertension, and HIV. The mechanistic rationale to explain these associations remains poorly understood. We believe that these seemingly unrelated entities may promote atherosclerosis through a common pathway by inducing adventitial autonomic dysfunction, specifically as an adventitial stress dysfunction of neurogenic origin. Atherosclerosis may represent a local vascular manifestation of the global autonomic dysfunction induced by age, smoking, hypertension, HIV, and diabetes. Atherosclerosis may also participate in a feed-forward cycle as aging, diabetes, dyslipidemia, and hypertension may also represent independent downstream consequences of global sympathetic bias. Chronic physiologic stress and behavioral stress can shift the autonomic balance towards a state of sympathetic predominance. The highly communicable nature of behavioral stress may partially implicate the familial association of atherosclerosis as an epigenetic phenomenon, independent of putative genetic mechanisms. Host stress, global autonomic dysfunction, and sympathetic bias may also arise from chronic maladaptive consumption of stressed foods, as organisms detect and assimilate the stress phenotypes of their dietary constituents through a process called xenohormesis. The benefits of exercise may operate through reduction of chronic physiologic stress associated with global sympathetic bias. The neurogenic adventitial stress response may explain the local tissue remodeling seen in atherosclerosis, including adventitial adipose dysfunction, inflammation, adventitial angiogenesis, thrombosis, and endothelial dysfunction. We believe that the locations of atherosclerotic lesions correspond to regions of neurogenic adventitial autonomic dysfunction, in similar fashion to the segmental patterns of involvement found in inflammatory bowel disease. The diffuse atherosclerosis exhibited in transplanted hearts may reflect a diffuse sympathetic bias of the donor heart, since tissues and organs exhibit an intrinsic sympathetic bias in the absence of an extrinsic source of autonomic hegemony. Once we regard atherosclerosis as a neurogenic phenomenon manifested in adventitial autonomic dysfunction, novel diagnostic and therapeutic paradigms become evident.
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Affiliation(s)
- Rakesh S Marwah
- Palo Alto Institute, 470 University Avenue, Palo Alto, CA 94301, USA
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128
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North BJ, Sinclair DA. Sirtuins: a conserved key unlocking AceCS activity. Trends Biochem Sci 2006; 32:1-4. [PMID: 17141505 PMCID: PMC2396790 DOI: 10.1016/j.tibs.2006.11.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 10/26/2006] [Accepted: 11/23/2006] [Indexed: 11/30/2022]
Abstract
Bacterial acetyl-coenzyme A (acetyl-CoA) synthetase (AceCS), an evolutionarily conserved enzyme that converts acetate to acetyl-CoA, is activated by sirtuin-mediated deacetylation. Two recent studies show that this mechanism of regulation is also crucial for mammalian AceCS activity, indicating that control of metabolism at the step of converting acetate to acetyl-CoA is conserved. These findings highlight a metabolic regulatory network controlled by sirtuins that has implications for the mechanisms of calorie restriction and modulation of mammalian lifespan.
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Affiliation(s)
- Brian J North
- Department of Pathology, Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
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129
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Cook R, Calabrese EJ. The importance of hormesis to public health. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:1631-5. [PMID: 17107845 PMCID: PMC1665397 DOI: 10.1289/ehp.8606] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND Hormesis is a specific type of nonmonotonic dose response whose occurrence has been documented across a broad range of biological models, diverse types of exposure, and a variety of outcomes. The effects that occur at various points along this curve can be interpreted as beneficial or detrimental, depending on the biological or ecologic context in which they occur. OBJECTIVE Because hormesis appears to be a relatively common phenomenon that has not yet been incorporated into regulatory practice, the objective of this commentary is to explore some of its more obvious public health and risk assessment implications, with particular reference to issues raised recently within this journal by other authors. DISCUSSION Hormesis appears to be more common than dose-response curves that are currently used in the risk assessment process [e.g., linear no-threshold (LNT)]. Although a number of mechanisms have been identified that explain many hormetic dose-response relationships, better understanding of this phenomenon will likely lead to different strategies not only for the prevention and treatment of disease but also for the promotion of improved public health as it relates to both specific and more holistic health outcomes. CONCLUSIONS We believe that ignoring hormesis is poor policy because it ignores knowledge that could be used to improve public health.
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Affiliation(s)
- Ralph Cook
- RRC Consulting, LLC, Midland, Michigan,
USA
| | - Edward J. Calabrese
- School of Public Health and Health Sciences,
Department of Environmental Health, University of Massachusetts, Amherst, Massachusetts,
USA
- Address correspondence to E.J. Calabrese, Department of
Environmental Health, School of Public Health and Health Sciences, University of
Massachusetts, Morrill Science I, N344, Amherst, MA 01003 USA. Telephone: (413) 545-3164.
Fax: (413) 545-4692. E-mail:
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130
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Swindell WR. The association among gene expression responses to nine abiotic stress treatments in Arabidopsis thaliana. Genetics 2006; 174:1811-24. [PMID: 17028338 PMCID: PMC1698639 DOI: 10.1534/genetics.106.061374] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The identification and analysis of genes exhibiting large expression responses to several different types of stress may provide insights into the functional basis of multiple stress tolerance in plant species. This study considered whole-genome transcriptional profiles from Arabidopsis thaliana root and shoot organs under nine abiotic stress conditions (cold, osmotic stress, salt, drought, genotoxic stress, ultraviolet light, oxidative stress, wounding, and high temperature) and at six different time points of stress exposure (0.5, 1, 3, 6, 12, and 24 hr). In roots, genomewide correlations between transcriptional responses to different stress treatments peaked following 1 hr of stress exposure, while in shoots, correlations tended to increase following 6 hr of stress exposure. The generality of stress responses at the transcriptional level was therefore time and organ dependent. A total of 67 genes were identified as exhibiting a statistically significant pattern of gene expression characterized by large transcriptional responses to all nine stress treatments. Most genes were identified from early to middle (1-6 hr) time points of stress exposure. Analysis of this gene set indicated that cell rescue/defense/virulence, energy, and metabolism functional classes were overrepresented, providing novel insight into the functional basis of multiple stress tolerance in Arabidopsis.
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Affiliation(s)
- William R Swindell
- Department of Probability and Statistics, Michigan State University, East Lansing, Michigan 48824, USA.
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131
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Anekonda TS. Resveratrol—A boon for treating Alzheimer's disease? ACTA ACUST UNITED AC 2006; 52:316-26. [PMID: 16766037 DOI: 10.1016/j.brainresrev.2006.04.004] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 04/18/2006] [Accepted: 04/19/2006] [Indexed: 11/16/2022]
Abstract
Resveratrol, a red wine polyphenol, is known to protect against cardiovascular diseases and cancers, as well as to promote antiaging effects in numerous organisms. It also modulates pathomechanisms of debilitating neurological disorders, such as strokes, ischemia, and Huntington's disease. The role of resveratrol in Alzheimer's disease is still unclear, although some recent studies on red wine bioactive compounds suggest that resveratrol modulates multiple mechanisms of Alzheimer's disease pathology. Emerging literature indicates that mechanisms of aging and Alzheimer's disease are intricately linked and that these mechanisms can be modulated by both calorie restriction regimens and calorie restriction mimetics, the prime mediator of which is the SIRT1 protein, a human homologue of yeast silent information regulator (Sir)-2, and a member of NAD+-dependent histone deacetylases. Calorie restriction regimens and calorie restriction-mimetics trigger sirtuins in a wide variety of organisms, ranging from bacteria to mouse. In a mouse model of Huntington's disease, resveratrol-induced SIRT1 was found to protect neurons against ployQ toxicity and in Wallerian degeneration slow mice, resveratrol was found to protect the degeneration of neurons from axotomy, suggesting that resveratrol may possess therapeutic value to neuronal degeneration. This paper mainly focuses on the role of resveratrol in modulating AD pathomechanisms.
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Affiliation(s)
- Thimmappa S Anekonda
- Neurological Sciences Institute, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, 97006, USA.
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132
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Abstract
Resveratrol mimics calorie restriction to extend lifespan of Caenorhabditis elegans, yeast and Drosophila, possibly through activation of Sir2 (silent information regulator 2), a NAD+-dependent histone deacetylase. In the present study, resveratrol is shown to inhibit the insulin signalling pathway in several cell lines and rat primary hepatocytes in addition to its broad-spectrum inhibition of several signalling pathways. Resveratrol effectively inhibits insulin-induced Akt and MAPK (mitogen-activated protein kinase) activation mainly through disruption of the interactions between insulin receptor substrates and its downstream binding proteins including p85 regulatory subunit of phosphoinositide 3-kinase and Grb2 (growth factor receptor-bound protein 2). The inhibitory effect of resveratrol on insulin signalling is also demonstrated at mRNA level, where resveratrol reverses insulin effects on phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, fatty acid synthase and glucokinase. In addition, RNA interference experiment shows that the inhibitory effect of resveratrol on insulin signalling pathway is not weakened in cells with reduced expression of SirT1, the mammalian counterpart of Sir2. These observations raise the possibility that resveratrol may additionally modulate lifespan through inhibition of insulin signalling pathway, independently of its activation of SirT1 histone deacetylase. Furthermore, the present study may help to explain a wide range of biological effects of resveratrol, and provides further insight into the molecular basis of calorie restriction.
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Affiliation(s)
- Jiandi Zhang
- Center for Human Nutrition, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9052, USA.
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133
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Qin W, Yang T, Ho L, Zhao Z, Wang J, Chen L, Zhao W, Thiyagarajan M, MacGrogan D, Rodgers JT, Puigserver P, Sadoshima J, Deng H, Pedrini S, Gandy S, Sauve AA, Pasinetti GM. Neuronal SIRT1 Activation as a Novel Mechanism Underlying the Prevention of Alzheimer Disease Amyloid Neuropathology by Calorie Restriction. J Biol Chem 2006; 281:21745-21754. [PMID: 16751189 DOI: 10.1074/jbc.m602909200] [Citation(s) in RCA: 475] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD)+-dependent sirtuins have been identified to be key regulators in the lifespan extending effects of calorie restriction (CR) in a number of species. In this study we report for the first time that promotion of the NAD+-dependent sirtuin, SIRT1-mediated deacetylase activity, may be a mechanism by which CR influences Alzheimer disease (AD)-type amyloid neuropathology. Most importantly, we report that the predicted attenuation of beta-amyloid content in the brain during CR can be reproduced in mouse neurons in vitro by manipulating cellular SIRT1 expression/activity through mechanisms involving the regulation of the serine/threonine Rho kinase ROCK1, known in part for its role in the inhibition of the non-amyloidogenic alpha-secretase processing of the amyloid precursor protein. Conversely, we found that the expression of constitutively active ROCK1 in vitro cultures significantly prevented SIRT1-mediated response, suggesting that alpha-secretase activity is required for SIRT1-mediated prevention of AD-type amyloid neuropathology. Consistently we found that the expression of exogenous human (h) SIRT1 in the brain of hSIRT1 transgenics also resulted in decreased ROCK1 expression and elevated alpha-secretase activity in vivo. These results demonstrate for the first time a role for SIRT1 activation in the brain as a novel mechanism through which CR may influence AD amyloid neuropathology. The study provides a potentially novel pharmacological strategy for AD prevention and/or treatment.
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Affiliation(s)
- Weiping Qin
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029
| | - Tianle Yang
- Department of Pharmacology, Tri-Institutional Program in Chemical Biology, Weill Medical College of Cornell University, New York, New York 10021
| | - Lap Ho
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029; Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029; Geriatric Research and Clinical Center, Bronx Veterans Affairs Medical Center, Bronx, New York 10468
| | - Zhong Zhao
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029
| | - Jun Wang
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029
| | - Linghong Chen
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029
| | - Wei Zhao
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029
| | | | - Donal MacGrogan
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029
| | - Joseph T Rodgers
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Pere Puigserver
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Junichi Sadoshima
- Cardiovascular Research Institute, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey 07103
| | - Haiteng Deng
- Proteomics Resource Center, The Rockefeller University, New York, New York 10021
| | - Steven Pedrini
- Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-5099
| | - Samuel Gandy
- Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-5099
| | - Anthony A Sauve
- Department of Pharmacology, Tri-Institutional Program in Chemical Biology, Weill Medical College of Cornell University, New York, New York 10021.
| | - Giulio M Pasinetti
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029; Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029; Geriatric Research and Clinical Center, Bronx Veterans Affairs Medical Center, Bronx, New York 10468.
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134
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Vargo MA, Voss OH, Poustka F, Cardounel AJ, Grotewold E, Doseff AI. Apigenin-induced-apoptosis is mediated by the activation of PKCdelta and caspases in leukemia cells. Biochem Pharmacol 2006; 72:681-92. [PMID: 16844095 DOI: 10.1016/j.bcp.2006.06.010] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 05/31/2006] [Accepted: 06/01/2006] [Indexed: 11/20/2022]
Abstract
Apigenin, a flavone abundantly found in fruits and vegetables, exhibits antiproliferative, anti-inflammatory, and antimetastatic activities through poorly defined mechanisms. In the present study, the treatment of different cell lines with apigenin resulted in selective antiproliferative and apoptotic effect in monocytic and lymphocytic leukemias. Apigenin-induced-apoptosis was mediated by the activation of caspase-9 and caspase-3. Apigenin was found intracellularly and localized to the mitochondria. Treatment of monocytic cells with apigenin was accompanied by an increase in reactive oxygen species (ROS) and phosphorylation of the MAPKs, p38 and ERK. However, the inhibition of ROS, p38 or ERK failed to block apoptosis, suggesting that these cellular responses induced by apigenin are not essential for the induction of apoptosis. In addition, apigenin induced the activation of PKCdelta. Pharmacological inhibition of PKCdelta, the expression of dominant-negative PKCdelta and silencing of PKCdelta in leukemia cells showed that apigenin-induced-apoptosis requires PKCdelta activity. Together, these results indicate that this flavonoid provides selective activity to promote caspase-dependent-apoptosis of leukemia cells and uncover an essential role of PKCdelta during the induction of apoptosis by apigenin.
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135
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Abstract
Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.
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Affiliation(s)
- Joseph A Baur
- Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
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136
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Howell A, Sims AH, Ong KR, Harvie MN, Evans DGR, Clarke RB. Mechanisms of Disease: prediction and prevention of breast cancer--cellular and molecular interactions. ACTA ACUST UNITED AC 2006; 2:635-46. [PMID: 16341119 DOI: 10.1038/ncponc0361] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 10/12/2005] [Indexed: 01/31/2023]
Abstract
Breast cancer is the most prevalent female cancer in the world and its incidence is increasing, largely because of the Western lifestyle. There is a need, not only to predict women who will develop the disease, but also to apply drug and lifestyle measures in order to prevent the disease. Current risk prediction models are based on combinations of risk factors and have good predictive but low discriminatory power. New risk prediction methods might come from examination of single nucleotide polymorphisms in several genes or from an increased knowledge of the molecular and cellular biology of the breast, particularly with respect to aberrant gene expression and protein synthesis. These methods might also determine new targets for preventive agents and lifestyle change. Many potential preventive measures are available and some have been successful. New approaches are required, however, not only to prevent the disease but to devise methods for their assessment that do not require very large and expensive clinical trials.
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Affiliation(s)
- Anthony Howell
- Dept of Medical Oncology, University of Manchester, Christie Hospital, Withington, UK.
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137
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Jeon JY, Bradley RL, Kokkotou EG, Marino FE, Wang X, Pissios P, Maratos-Flier E. MCH-/- mice are resistant to aging-associated increases in body weight and insulin resistance. Diabetes 2006; 55:428-34. [PMID: 16443777 DOI: 10.2337/diabetes.55.02.06.db05-0203] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ablation of the hypothalamic peptide, melanin-concentrating hormone (MCH), leads to a lean phenotype and resistance to diet-induced obesity. Observation of MCH(-/-) mice at older ages suggested that these effects persist in mice >1 year old. Leanness secondary to caloric restriction is known to be associated with improved glucose tolerance as well as an overall increase in life span. Because the MCH(-/-) model represents leanness secondary to increased energy expenditure rather than caloric restriction, we were interested in determining whether this model of leanness would be associated with beneficial metabolic effects at older ages. To assess the effects of MCH ablation over a more prolonged period, we monitored male and female MCH(-/-) mice up to 19 months. The lean phenotype of MCH(-/-) mice persisted over the duration of the study. At 19 months, MCH(-/-) male and female mice weighed 23.4 and 30.8% less than their wild-type counterparts, a result of reduced fat mass in MCH(-/-) mice. Aged MCH(-/-) mice exhibited better glucose tolerance and were more insulin sensitive compared with wild-type controls. Aging-associated decreases in locomotor activity were also attenuated in MCH(-/-) mice. We also evaluated two molecules implicated in the pathophysiology of aging, p53 and silent inflammatory regulator 2 (Sir2). We found that expression of the tumor suppressor protein p53 was higher in MCH(-/-) mice at 9 and 19 months of age. In contrast, expression of Sir2 was unchanged. In aggregate, these findings suggest that MCH ablation improves the long-term outcome for several indicators of the aging process.
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Affiliation(s)
- Justin Y Jeon
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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138
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Galli C. Bioactive minor compounds of extra-virgin olive oil: the ibuprofen-like activity of oleocanthal. EUR J LIPID SCI TECH 2006. [DOI: 10.1002/ejlt.200690010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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139
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Myhrstad MCW, Carlsen H, Dahl LI, Ebihara K, Glemmestad L, Haffner K, Moskaug JØ, Blomhoff R. Bilberry Extracts Induce Gene Expression Through the Electrophile Response Element. Nutr Cancer 2006; 54:94-101. [PMID: 16800777 DOI: 10.1207/s15327914nc5401_11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
A number of genes important for detoxification and antioxidant defense induced by mild stress generated by, for example, physical activity/exercise, caloric restriction, or alcohol may provide health benefits by causing the organism to mount such a defense response. More recently, induction of these defenses has also been attributed to phytochemicals or secondary metabolites from dietary plants. Many polyphenols, which constitute a large fraction of these phytochemicals, increase cellular levels of antioxidants, such as glutathione and other components of the detoxification systems, via the transactivation of genes containing electrophile response elements (EpREs) within their promoters. One such gene, gamma-glutamylcysteine synthetase, has previously been shown to be positively regulated by quercetin, a flavonoid found in high concentrations in onions, apples, and bilberries through EpRE transactivation. As a further step, we have investigated whether bilberries and quercetin have the ability to induce transcription of Fos-related antigen 1 (Fra-1), which contains two EpREs in its promoter. Fra-1 is a member of the activator protein 1 (AP-1) family of transcription factors and, due to the lack of transactivation domain Fra-1, can suppress activation of AP-1. We present results demonstrating that extracts from bilberries, and the flavonoid quercetin, abundant in bilberries, induce the fra-1 promoter and the cellular content of Fra-1 mRNA. We further provide evidence that this induction is mediated through EpREs.
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140
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Abstract
Yeast has essentially two lifespans: a replicative lifespan (the number of daughters produced by each dividing mother cell) and a chronological lifespan (the capacity of stationary (G0) cultures to maintain viability over time). There is a tendency now to label every investigation that addresses these lifespans as ageing research. It is, though, analyses of the longest lifespans that will be most informative about the determinants of longevity and yield results most relevant to ageing in more complex systems. This review addresses these issues and describes the ongoing studies that are now attempting to address ageing in yeast cells of maximal replicative or chronological longevity.
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Affiliation(s)
- Peter W Piper
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
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141
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Bordone L, Motta MC, Picard F, Robinson A, Jhala US, Apfeld J, McDonagh T, Lemieux M, McBurney M, Szilvasi A, Easlon EJ, Lin SJ, Guarente L. Sirt1 regulates insulin secretion by repressing UCP2 in pancreatic beta cells. PLoS Biol 2005; 4:e31. [PMID: 16366736 PMCID: PMC1318478 DOI: 10.1371/journal.pbio.0040031] [Citation(s) in RCA: 522] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Accepted: 11/22/2005] [Indexed: 02/06/2023] Open
Abstract
Sir2 and insulin/IGF-1 are the major pathways that impinge upon aging in lower organisms. In Caenorhabditis elegans a possible genetic link between Sir2 and the insulin/IGF-1 pathway has been reported. Here we investigate such a link in mammals. We show that Sirt1 positively regulates insulin secretion in pancreatic β cells. Sirt1 represses the uncoupling protein (UCP) gene UCP2 by binding directly to the UCP2 promoter. In β cell lines in which Sirt1 is reduced by SiRNA, UCP2 levels are elevated and insulin secretion is blunted. The up-regulation of UCP2 is associated with a failure of cells to increase ATP levels after glucose stimulation. Knockdown of UCP2 restores the ability to secrete insulin in cells with reduced Sirt1, showing that UCP2 causes the defect in glucose-stimulated insulin secretion. Food deprivation induces UCP2 in mouse pancreas, which may occur via a reduction in NAD (a derivative of niacin) levels in the pancreas and down-regulation of Sirt1. Sirt1 knockout mice display constitutively high UCP2 expression. Our findings show that Sirt1 regulates UCP2 in β cells to affect insulin secretion. Sirt1 is shown to regulate the expression of the metabolic decoupling gene UCP2 in pancreatic β cells, highlighting a possible role for Sirt1 in coordinating insulin release in response to changing dietary conditions.
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Affiliation(s)
- Laura Bordone
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail: (LB); E-mail: (LG)
| | - Maria Carla Motta
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Frederic Picard
- 2Laval Hospital Research Center, Québec City, Québec, Canada
| | - Ashley Robinson
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Ulupi S Jhala
- 3The Whittier Institute for Diabetes, University of California San Diego, La Jolla, California, United States of America
| | - Javier Apfeld
- 4Elixir Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Thomas McDonagh
- 4Elixir Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Madeleine Lemieux
- 5Department of Medicine and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, and the Ottawa Regional Cancer Centre, Ottawa, Ontario, Canada
| | - Michael McBurney
- 5Department of Medicine and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, and the Ottawa Regional Cancer Centre, Ottawa, Ontario, Canada
| | - Akos Szilvasi
- 6Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Erin J Easlon
- 7Center for Genetics and Development, and Section of Microbiology, University of California Davis, Davis, California, United States of America
| | - Su-Ju Lin
- 7Center for Genetics and Development, and Section of Microbiology, University of California Davis, Davis, California, United States of America
| | - Leonard Guarente
- 1Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail: (LB); E-mail: (LG)
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142
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Porcu M, Chiarugi A. The emerging therapeutic potential of sirtuin-interacting drugs: from cell death to lifespan extension. Trends Pharmacol Sci 2005; 26:94-103. [PMID: 15681027 DOI: 10.1016/j.tips.2004.12.009] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acetylation of chromatin-interacting proteins is central to the epigenetic regulation of genome architecture and gene expression. Chemicals that modulate the acetylation of nuclear proteins have proved instrumental in experimental models of several human diseases. Sirtuins represent a new class of evolutionary conserved histone deacetylases, originally identified in yeast, that have emerging pathogenetic roles in cancer, diabetes, muscle differentiation, heart failure, neurodegeneration and aging. In this article, we focus on sirtuins and provide an appraisal of current compounds that either activate or inhibit sirtuin activity, highlighting their therapeutic potential for the treatment of human diseases.
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Affiliation(s)
- Marco Porcu
- Department of Preclinical and Clinical Pharmacology, University of Florence, 50139 Florence, Italy
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143
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Mai A, Massa S, Lavu S, Pezzi R, Simeoni S, Ragno R, Mariotti FR, Chiani F, Camilloni G, Sinclair DA. Design, Synthesis, and Biological Evaluation of Sirtinol Analogues as Class III Histone/Protein Deacetylase (Sirtuin) Inhibitors. J Med Chem 2005; 48:7789-95. [PMID: 16302818 DOI: 10.1021/jm050100l] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a search for potent inhibitors of class III histone/protein deacetylases (sirtuins), a series of sirtinol analogues have been synthesized and the degree of inhibition was assessed in vitro using recombinant yeast Sir2, human SIRT1, and human SIRT2 and in vivo with a yeast phenotypic assay. Two analogues, namely, 3- and 4-[(2-hydroxy-1-naphthalenylmethylene)amino]-N-(1-phenylethyl)benzamide (i.e., m- and p-sirtinol), were 2- to 10-fold more potent than sirtinol against human SIRT1 and SIRT2 enzymes. In yeast in vivo assay, these two small molecules were as potent as sirtinol. Compounds lacking the 2-hydroxy group at the naphthalene moiety or bearing several modifications at the benzene 2'-position of the aniline portion (carbethoxy, carboxy, and cyano) were 1.3-13 times less potent than sirtinol, whereas the 2'-carboxamido analogue was totally inactive. Both (R)- and (S)-sirtinol had similar inhibitory effects on the yeast and human enzymes, demonstrating no enantioselective inhibitory effect.
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Affiliation(s)
- Antonello Mai
- Dipartimento di Studi Farmaceutici, Istituto Pasteur, Fondazione Cenci Bolognetti, Università degli Studi di Roma "La Sapienza", P. le A. Moro 5, 00185 Roma, Italy.
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144
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Kharade SV, Mittal N, Das SP, Sinha P, Roy N. Mrg19 depletion increasesS. cerevisiaelifespan by augmenting ROS defence. FEBS Lett 2005; 579:6809-13. [PMID: 16336970 DOI: 10.1016/j.febslet.2005.11.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 10/05/2005] [Accepted: 11/08/2005] [Indexed: 11/29/2022]
Abstract
Caloric restriction (CR) is the most compelling example of lifespan extension by external manipulation. Although the molecular mechanisms remain unknown, the theory of hormesis has been invoked to explain the life promoting effects of CR. Hormesis is defined as the beneficial effects of low intensity stressor on a cell or organism. Mrg19 is a putative transcription factor that regulates carbon and nitrogen metabolism in yeast. In this study, we have found that deletion of MRG19 gene causes metabolic shift in yeast cells, leading to higher intracellular reactive oxygen species, augmentation of scavenging enzymes and longer lifespan compared to wild-type cells. All these results together suggest that similar to CR, depletion of Mrg19 leads to a condition of mild stress which in turn enhances vitality.
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Affiliation(s)
- Sujay V Kharade
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab 160062, India
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145
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Sinclair DA. Toward a unified theory of caloric restriction and longevity regulation. Mech Ageing Dev 2005; 126:987-1002. [PMID: 15893363 DOI: 10.1016/j.mad.2005.03.019] [Citation(s) in RCA: 398] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 02/03/2005] [Accepted: 03/15/2005] [Indexed: 12/15/2022]
Abstract
The diet known as calorie restriction (CR) is the most reproducible way to extend the lifespan of mammals. Many of the early hypotheses to explain this effect were based on it being a passive alteration in metabolism. Yet, recent data from yeast, worms, flies, and mammals support the idea that CR is not simply a passive effect but an active, highly conserved stress response that evolved early in life's history to increase an organism's chance of surviving adversity. This perspective updates the evidence for and against the various hypotheses of CR, and concludes that many of them can be synthesized into a single, unifying hypothesis. This has important implications for how we might develop novel medicines that can harness these newly discovered innate mechanisms of disease resistance and survival.
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Affiliation(s)
- David A Sinclair
- Department of Pathology, Harvard Medical School, 77 Avenue Louis Paster, Boston, MA 02115, USA.
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146
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Vergnes B, Sereno D, Tavares J, Cordeiro-da-Silva A, Vanhille L, Madjidian-Sereno N, Depoix D, Monte-Alegre A, Ouaissi A. Targeted disruption of cytosolic SIR2 deacetylase discloses its essential role in Leishmania survival and proliferation. Gene 2005; 363:85-96. [PMID: 16236469 DOI: 10.1016/j.gene.2005.06.047] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 06/08/2005] [Accepted: 06/27/2005] [Indexed: 11/20/2022]
Abstract
Proteins of the SIR2 family are characterized by a conserved catalytic domain that exerts unique NAD-dependent deacetylase activity on histone and various other cellular substrates. Functional analyses of such proteins have been carried out in a number of prokaryotes and eukaryotes organisms but until now, none have described an essential function for any SIR2 genes. Here using genetic approach, we report that a cytosolic SIR2 homolog in Leishmania is determinant to parasite survival. L. infantum promastigote tolerates deletion of one wild-type LiSIR2 allele (LiSIR2+/-) but achievement of null chromosomal mutants (LiSIR2-/-) requires episomal rescue. Accordingly, plasmid cure shows that these parasites maintain episome even in absence of drug pressure. Though single LiSIR2 gene disruption (LiSIR2+/-) does not affect the growth of parasite in the promastigote form, axenic amastigotes display a marked reduction in their capacity to multiply in vitro inside macrophages and in vivo in Balb/c mice. Taken together these data support a stage specific requirement and/or activity of the Leishmania cytosolic SIR2 protein and reveal an unrelated essential function for the life cycle of this unicellular pathogenic organism. The lack of an effective vaccine against leishmaniasis, and the need for alternative drug treatments, makes LiSIR2 protein a new attractive therapeutic target.
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Affiliation(s)
- Baptiste Vergnes
- IRD UR008 Pathogénie des Trypanosomatidés, Institut de Recherche pour le Développement, Centre IRD de Montpellier, 911 Av. Agropolis, BP 5045, 34032, Montpellier, France
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147
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Abstract
Silent information regulator 2, a member of NAD+-dependent histone deacetylase in yeast, and its homologs in mice and humans, participate in numerous important cell functions, including cell protection and cell cycle regulation. The sirtuin family members are highly conserved evolutionarily, and are predicted to have a role in cell survival. The science of sirtuins is an emerging field and is expected to contribute significantly to the role of sirtuins in healthy aging in humans. The role of sirtuins in neuronal protection has been studied in lower organisms, such as yeast, worms, flies and rodents. Both yeast Sir2 and mammalian sirtuin proteins are up-regulated under calorie-restricted and resveratrol treatments. Increased sirtuin expression protects cells from various insults. Caloric restriction and antioxidant treatments have shown useful effects in mouse models of aging and Alzheimer's disease (AD) and in limited human AD clinical trials. The role sirtuins may play in modifying and protecting neurons in patients with neurodegenerative diseases is still unknown. However, a recent report of Huntington's disease revealed that Sirtuin protects neurons in a Huntington's disease mouse model, suggesting that sirtuins may protect neurons in patients with neurodegenerative diseases, such as AD. In this review, we discuss the possible mechanisms of sirtuins involved in neuronal protection and the potential therapeutic value of sirtuins in healthy aging and AD.
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Affiliation(s)
- Thimmappa S Anekonda
- Neurogenetics Laboratory, Neurological Sciences Institute, Oregon Health and Science University, Beaverton, Oregon 97006, USA
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148
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Abstract
The size and frequency of meals are fundamental aspects of nutrition that can have profound effects on the health and longevity of laboratory animals. In humans, excessive energy intake is associated with increased incidence of cardiovascular disease, diabetes, and certain cancers and is a major cause of disability and death in industrialized countries. On the other hand, the influence of meal frequency on human health and longevity is unclear. Both caloric (energy) restriction (CR) and reduced meal frequency/intermittent fasting can suppress the development of various diseases and can increase life span in rodents by mechanisms involving reduced oxidative damage and increased stress resistance. Many of the beneficial effects of CR and fasting appear to be mediated by the nervous system. For example, intermittent fasting results in increased production of brain-derived neurotrophic factor (BDNF), which increases the resistance of neurons in the brain to dysfunction and degeneration in animal models of neurodegenerative disorders; BDNF signaling may also mediate beneficial effects of intermittent fasting on glucose regulation and cardiovascular function. A better understanding of the neurobiological mechanisms by which meal size and frequency affect human health may lead to novel approaches for disease prevention and treatment.
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Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, and Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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149
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Abstract
Ageing is characterized by a progressive accumulation of molecular damage in nucleic acids, proteins and lipids. The inefficiency and failure of maintenance, repair and turnover pathways is the main cause of age-related accumulation of damage. Research in molecular gerontology is aimed at understanding the genetic and epigenetic regulation of survival and maintenance mechanisms at the levels of transcription, post-transcriptional processing, post-translational modifications, and interactions among various gene products. Concurrently, several approaches are being tried and tested to modulate ageing in a wide variety of organisms. The ultimate aim of such studies is to improve the quality of human life in old age and prolong the health-span. Various gerontomodulatory approaches include gene therapy, hormonal supplementation, nutritional modulation and intervention by free radical scavengers and other molecules. A recent approach is that of applying hormesis in ageing research and therapy, which is based on the principle of stimulation of maintenance and repair pathways by repeated exposure to mild stress. A combination of molecular, physiological and psychological modulatory approaches can realize "healthy ageing" as an achievable goal in the not-so-distant future.
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Affiliation(s)
- Suresh I S Rattan
- Danish Centre for Molecular Gerontology, Department of Molecular Biology, University of Aarhus, Aarhus, Denmark.
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150
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Alonso DA, Fuensanta M, Nájera C, Varea M. 3,5-Bis(trifluoromethyl)phenyl Sulfones in the Direct Julia−Kocienski Olefination. J Org Chem 2005; 70:6404-16. [PMID: 16050703 DOI: 10.1021/jo050852n] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3,5-bis(trifluoromethyl)phenyl (BTFP) sulfones 7 have been employed in the Julia-Kocienski olefination reaction with carbonyl compounds. Sulfones 7 are readily prepared in high yields (64-97%) from commercially available 3,5-bis(trifluoromethyl)thiophenol through an alkylation/oxidation two-step sequence. The stability of metalated BTFP sulfones has been studied and compared with heteroaryl benzothiazol-2-yl (BT), 1-phenyl-1H-tetrazol-5-yl (PT), and 1-tert-butyl-1H-tetrazol-5-yl (TBT) sulfones 9-11 under different reaction conditions. The Julia-Kocienski olefination between alkyl BTFP sulfones 7 and a wide variety of aldehydes affords the corresponding 1,2-disubstituted alkenes and dienes in good yields and stereoselectivities. This one-pot protocol can be performed using KOH at room temperature or the phosphazene bases P2-Et and P4-t-Bu at -78 degrees C or rt and has been successfully used in a high-yielding and stereoselective synthesis of various methoxylated stilbenes such as trimethylated resveratrol. These new reaction conditions for the Julia-Kocienski olefination reaction have been also studied with BT, PT, and TBT sulfones, giving poorer results. Methylenation of aliphatic and aromatic aldehydes, ketones, and 1,2-dicarbonyl compounds is carried out through the modified Julia olefination using BTFP methyl sulfone 7d to give terminal alkenes and dienes. Mechanistic studies of the olefination reaction between benzyl BTFP sulfone 7a and aromatic aldehydes performed by KOH-induced Smiles rearrangement of stereodefined syn- and anti-beta-hydroxyalkyl BTFP sulfones indicate that the stereocontrol of the reaction is determined in the elimination step.
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Affiliation(s)
- Diego A Alonso
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Facultad de Ciencias, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
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