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Newsom SA, Miller BF, Hamilton KL, Ehrlicher SE, Stierwalt HD, Robinson MM. Long-term rates of mitochondrial protein synthesis are increased in mouse skeletal muscle with high-fat feeding regardless of insulin-sensitizing treatment. Am J Physiol Endocrinol Metab 2017; 313:E552-E562. [PMID: 28698283 PMCID: PMC5792140 DOI: 10.1152/ajpendo.00144.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/05/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022]
Abstract
Skeletal muscle mitochondrial protein synthesis is regulated in part by insulin. The development of insulin resistance with diet-induced obesity may therefore contribute to impairments to protein synthesis and decreased mitochondrial respiration. Yet the impact of diet-induced obesity and insulin resistance on mitochondrial energetics is controversial, with reports varying from decreases to increases in mitochondrial respiration. We investigated the impact of changes in insulin sensitivity on long-term rates of mitochondrial protein synthesis as a mechanism for changes to mitochondrial respiration in skeletal muscle. Insulin resistance was induced in C57BL/6J mice using 4 wk of a high-fat compared with a low-fat diet. For 8 additional weeks, diets were enriched with pioglitazone to restore insulin sensitivity compared with nonenriched control low-fat or high-fat diets. Skeletal muscle mitochondrial protein synthesis was measured using deuterium oxide labeling during weeks 10-12 High-resolution respirometry was performed using palmitoyl-l-carnitine, glutamate+malate, and glutamate+malate+succinate as substrates for mitochondria isolated from quadriceps. Mitochondrial protein synthesis and palmitoyl- l-carnitine oxidation were increased in mice consuming a high-fat diet, regardless of differences in insulin sensitivity with pioglitazone treatment. There was no effect of diet or pioglitazone treatment on ADP-stimulated respiration or H2O2 emission using glutamate+malate or glutamate+malate+succinate. The results demonstrate no impairments to mitochondrial protein synthesis or respiration following induction of insulin resistance. Instead, mitochondrial protein synthesis was increased with a high-fat diet and may contribute to remodeling of the mitochondria to increase lipid oxidation capacity. Mitochondrial adaptations with a high-fat diet appear driven by nutrient availability, not intrinsic defects that contribute to insulin resistance.
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Affiliation(s)
- Sean A Newsom
- School of Biological and Population Health Sciences, College of Public Health and Human Sciences, Oregon State University, Corvallis, Oregon
| | - Benjamin F Miller
- Department of Health and Exercise Science, College of Health and Human Sciences, Colorado State University, Fort Collins, Colorado; and
| | - Karyn L Hamilton
- Department of Health and Exercise Science, College of Health and Human Sciences, Colorado State University, Fort Collins, Colorado; and
| | - Sarah E Ehrlicher
- School of Biological and Population Health Sciences, College of Public Health and Human Sciences, Oregon State University, Corvallis, Oregon
| | - Harrison D Stierwalt
- School of Biological and Population Health Sciences, College of Public Health and Human Sciences, Oregon State University, Corvallis, Oregon
| | - Matthew M Robinson
- School of Biological and Population Health Sciences, College of Public Health and Human Sciences, Oregon State University, Corvallis, Oregon;
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota
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Drake JC, Yan Z. Mitophagy in maintaining skeletal muscle mitochondrial proteostasis and metabolic health with ageing. J Physiol 2017; 595:6391-6399. [PMID: 28795394 PMCID: PMC5638883 DOI: 10.1113/jp274337] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/05/2017] [Indexed: 12/26/2022] Open
Abstract
Skeletal muscle is important for overall functionality and health. Ageing is associated with an accumulation of damage to mitochondrial DNA and proteins. In particular, damage to mitochondrial proteins in skeletal muscle, which is a loss of mitochondrial proteostasis, contributes to tissue dysfunction and negatively impacts systemic health. Therefore, understanding the mechanisms underlying the regulation of mitochondrial proteostasis and how those mechanisms change with age is important for the development of interventions to promote healthy ageing. Herein, we examine how impairment in the selective degradation of damaged/dysfunctional mitochondria through mitophagy may play a central role in the loss of mitochondrial proteostasis in skeletal muscle ageing, as well as its broader implications for systemic health. Further, we explore how stimulating mitophagy through exercise may promote healthy ageing.
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Affiliation(s)
- Joshua C. Drake
- Department of MedicineUniversity of Virginia School of MedicineCharlottesvilleVA22908USA
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research CenterUniversity of Virginia School of MedicineCharlottesvilleVA22908USA
| | - Zhen Yan
- Department of MedicineUniversity of Virginia School of MedicineCharlottesvilleVA22908USA
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research CenterUniversity of Virginia School of MedicineCharlottesvilleVA22908USA
- Department of PharmacologyUniversity of Virginia School of MedicineCharlottesvilleVA22908USA
- Department of Molecular Physiology and Biological PhysicsUniversity of Virginia School of MedicineCharlottesvilleVA22908USA
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Konopka AR, Castor WM, Wolff CA, Musci RV, Reid JJ, Laurin JL, Valenti ZJ, Hamilton KL, Miller BF. Skeletal muscle mitochondrial protein synthesis and respiration in response to the energetic stress of an ultra-endurance race. J Appl Physiol (1985) 2017; 123:1516-1524. [PMID: 28883046 DOI: 10.1152/japplphysiol.00457.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The 2016 Colorado Trail Race (CTR) was an ultra-endurance mountain bike race in which competitors cycled for up to 24 h/day between altitudes of 1,675 and 4,025 m to complete 800 km and 21,000 m of elevation gain. In one athlete, we had the unique opportunity to characterize skeletal muscle protein synthesis and mitochondrial respiration in response to a normal activity control period (CON) and the CTR. We hypothesized that mitochondrial protein synthesis would be elevated and mitochondrial respiration would be maintained during the extreme stresses of the CTR. Titrated and bolus doses of ADP were provided to determine substrate-specific oxidative phosphorylation (OXPHOS) and electron transport system (ETS) capacities in permeabilized muscle fibers via high-resolution respirometry. Protein synthetic rates were determined by daily oral consumption of deuterium oxide (2H2O). The endurance athlete had OXPHOS (226 pmol·s-1·mg tissue-1) and ETS (231 pmol·s-1·mg tissue-1) capacities that rank among the highest published to date in humans. Mitochondrial (3.2-fold), cytoplasmic (2.3-fold), and myofibrillar (1.5-fold) protein synthesis rates were greater during CTR compared with CON. With titrated ADP doses, the apparent Km of ADP, OXPHOS, and ETS increased after the CTR. With provision of ADP boluses after the CTR, the addition of fatty acids (-12 and -14%) mitigated the decline in OXPHOS and ETS capacity during carbohydrate-supported respiration (-26 and -31%). In the face of extreme stresses during the CTR, elevated rates of mitochondrial protein synthesis may contribute to rapid adaptations in mitochondrial bioenergetics. NEW & NOTEWORTHY The mechanisms that maintain skeletal muscle function during extreme stresses remain incompletely understood. In the current study, greater rates of mitochondrial protein synthesis during the energetic demands of ultra-endurance exercise may contribute to rapid adaptations in mitochondrial bioenergetics. The endurance athlete herein achieved mitochondrial respiratory capacities among the highest published for humans. Greater mitochondrial protein synthesis during ultra-endurance exercise may contribute to improved mitochondrial respiration and serve as a mechanism to resist cellular energetic stresses.
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Affiliation(s)
- Adam R Konopka
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado.,Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign , Urbana, Illinois
| | - William M Castor
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Christopher A Wolff
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Robert V Musci
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Justin J Reid
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Jaime L Laurin
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Zackary J Valenti
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
| | - Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado
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Hamilton KL, Miller BF. Mitochondrial proteostasis as a shared characteristic of slowed aging: the importance of considering cell proliferation. J Physiol 2017; 595:6401-6407. [PMID: 28719097 DOI: 10.1113/jp274335] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 06/21/2017] [Indexed: 12/28/2022] Open
Abstract
Proteostasis is one of the seven "pillars of aging research" identified by the Trans-NIH Geroscience Initiative and loss of proteostasis is associated with aging and age-related chronic disease. Accumulated protein damage and resultant cellular dysfunction are consequences of limited protein repair systems and slowed protein turnover. When relatively high rates of protein turnover are maintained despite advancing age, damaged proteins are more quickly degraded and replaced, maintaining proteome fidelity. Therefore, maintenance of protein turnover represents an important proteostatic mechanism. However, measurement of protein synthesis without consideration for cell proliferation can result in an incomplete picture, devoid of information about how new proteins are being allocated. Simultaneous measurement of protein and DNA synthesis provides necessary mechanistic insight about proteins apportioned for newly proliferating cells versus for somatic maintenance. Using this approach with a number of murine models of slowed aging shows that, compared to controls, energetic resources are directed more toward somatic maintenance and proteostasis, and away from cell growth and proliferation. In particular, slowed aging models are associated with heightened mechanisms of mitochondrial proteostatic maintenance. Taking cell proliferation into account may explain the paradoxical findings that aging itself and slowed aging interventions can both be characterized by slower rates of protein synthesis.
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Affiliation(s)
- Karyn L Hamilton
- Translational Research on Aging and Chronic Disease Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523-1582, USA
| | - Benjamin F Miller
- Translational Research on Aging and Chronic Disease Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523-1582, USA
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Gheller BJF, Riddle ES, Lem MR, Thalacker-Mercer AE. Understanding Age-Related Changes in Skeletal Muscle Metabolism: Differences Between Females and Males. Annu Rev Nutr 2017; 36:129-56. [PMID: 27431365 DOI: 10.1146/annurev-nutr-071715-050901] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Skeletal muscle is the largest metabolic organ system in the human body. As such, metabolic dysfunction occurring in skeletal muscle impacts whole-body nutrient homeostasis. Macronutrient metabolism changes within the skeletal muscle with aging, and these changes are associated in part with age-related skeletal muscle remodeling. Moreover, age-related changes in skeletal muscle metabolism are affected differentially between males and females and are likely driven by changes in sex hormones. Intrinsic and extrinsic factors impact observed age-related changes and sex-related differences in skeletal muscle metabolism. Despite some support for sex-specific differences in skeletal muscle metabolism with aging, more research is necessary to identify underlying differences in mechanisms. Understanding sex-specific aging skeletal muscle will assist with the development of therapies to attenuate adverse metabolic and functional outcomes.
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Affiliation(s)
- Brandon J F Gheller
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853;
| | - Emily S Riddle
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853;
| | - Melinda R Lem
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853;
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Pettit AP, Jonsson WO, Bargoud AR, Mirek ET, Peelor FF, Wang Y, Gettys TW, Kimball SR, Miller BF, Hamilton KL, Wek RC, Anthony TG. Dietary Methionine Restriction Regulates Liver Protein Synthesis and Gene Expression Independently of Eukaryotic Initiation Factor 2 Phosphorylation in Mice. J Nutr 2017; 147:1031-1040. [PMID: 28446632 PMCID: PMC5443467 DOI: 10.3945/jn.116.246710] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 01/20/2017] [Accepted: 03/15/2017] [Indexed: 01/12/2023] Open
Abstract
Background: The phosphorylation of eukaryotic initiation factor 2 (p-eIF2) during dietary amino acid insufficiency reduces protein synthesis and alters gene expression via the integrated stress response (ISR).Objective: We explored whether a Met-restricted (MR) diet activates the ISR to reduce body fat and regulate protein balance.Methods: Male and female mice aged 3-6 mo with either whole-body deletion of general control nonderepressible 2 (Gcn2) or liver-specific deletion of protein kinase R-like endoplasmic reticulum kinase (Perk) alongside wild-type or floxed control mice were fed an obesogenic diet sufficient in Met (0.86%) or an MR (0.12% Met) diet for ≤5 wk. Ala enrichment with deuterium was measured to calculate protein synthesis rates. The guanine nucleotide exchange factor activity of eIF2B was measured alongside p-eIF2 and hepatic mRNA expression levels at 2 d and 5 wk. Metabolic phenotyping was conducted at 4 wk, and body composition was measured throughout. Results were evaluated with the use of ANOVA (P < 0.05).Results: Feeding an MR diet for 2 d did not increase hepatic p-eIF2 or reduce eIF2B activity in wild-type or Gcn2-/- mice, yet many genes transcriptionally regulated by the ISR were altered in both strains in the same direction and amplitude. Feeding an MR diet for 5 wk increased p-eIF2 and reduced eIF2B activity in wild-type but not Gcn2-/- mice, yet ISR-regulated genes altered in both strains similarly. Furthermore, the MR diet reduced mixed and cytosolic but not mitochondrial protein synthesis in both the liver and skeletal muscle regardless of Gcn2 status. Despite the similarities between strains, the MR diet did not increase energy expenditure or reduce body fat in Gcn2-/- mice. Finally, feeding the MR diet to mice with Perk deleted in the liver increased hepatic p-eIF2 and altered body composition similar to floxed controls.Conclusions: Hepatic activation of the ISR resulting from an MR diet does not require p-eIF2. Gcn2 status influences body fat loss but not protein balance when Met is restricted.
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Affiliation(s)
- Ashley P Pettit
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - William O Jonsson
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Albert R Bargoud
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Emily T Mirek
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Frederick F Peelor
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO
| | - Yongping Wang
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ
| | - Thomas W Gettys
- Laboratory of Nutrient Sensing and Adipocyte Signaling, Pennington Biomedical Research Center, Baton Rouge, LA
| | - Scot R Kimball
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA; and
| | - Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO
| | - Ronald C Wek
- Department of Biochemistry of Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Tracy G Anthony
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ;
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Konopka AR, Laurin JL, Musci RV, Wolff CA, Reid JJ, Biela LM, Zhang Q, Peelor FF, Melby CL, Hamilton KL, Miller BF. Influence of Nrf2 activators on subcellular skeletal muscle protein and DNA synthesis rates after 6 weeks of milk protein feeding in older adults. GeroScience 2017; 39:175-186. [PMID: 28283797 DOI: 10.1007/s11357-017-9968-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/02/2017] [Indexed: 12/12/2022] Open
Abstract
In older adults, chronic oxidative and inflammatory stresses are associated with an impaired increase in skeletal muscle protein synthesis after acute anabolic stimuli. Conjugated linoleic acid (CLA) and Protandim have been shown to activate nuclear factor erythroid-derived 2-like 2 (Nrf2), a transcription factor for the antioxidant response element and anti-inflammatory pathways. This study tested the hypothesis that compared to a placebo control (CON), CLA and Protandim would increase skeletal muscle subcellular protein (myofibrillar, mitochondrial, cytoplasmic) and DNA synthesis in older adults after 6 weeks of milk protein feeding. CLA decreased oxidative stress and skeletal muscle oxidative damage with a trend to increase messenger RNA (mRNA) expression of a Nrf2 target, NAD(P)H dehydrogenase quinone 1 (NQO1). However, CLA did not influence other Nrf2 targets (heme oxygenase-1 (HO-1), glutathione peroxidase 1 (Gpx1)) or protein or DNA synthesis. Conversely, Protandim increased HO-1 protein content but not the mRNA expression of downstream Nrf2 targets, oxidative stress, or skeletal muscle oxidative damage. Rates of myofibrillar protein synthesis were maintained despite lower mitochondrial and cytoplasmic protein syntheses after Protandim versus CON. Similarly, DNA synthesis was non-significantly lower after Protandim compared to CON. After Protandim, the ratio of protein to DNA synthesis tended to be greater in the myofibrillar fraction and maintained in the mitochondrial and cytoplasmic fractions, emphasizing the importance of measuring both protein and DNA synthesis to gain insight into proteostasis. Overall, these data suggest that Protandim may enhance proteostatic mechanisms of skeletal muscle contractile proteins after 6 weeks of milk protein feeding in older adults.
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Affiliation(s)
- Adam R Konopka
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA.
| | - Jaime L Laurin
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Robert V Musci
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Christopher A Wolff
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Justin J Reid
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Laurie M Biela
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Qian Zhang
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Fredrick F Peelor
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Christopher L Melby
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
| | - Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University, 110 Moby B Complex, Fort Collins, CO, 80523, USA
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Abstract
Mitochondria were first postulated to contribute to aging more than 40 years ago. During the following decades, multiple lines of evidence in model organisms and humans showed that impaired mitochondrial function can contribute to age-associated disease phenotypes and aging. However, in contrast to the original theory favoring oxidative damage as a cause for mtDNA mutations, there are now strong data arguing that most mammalian mtDNA mutations originate as replication errors made by the mtDNA polymerase. Currently, a substantial amount of mitochondrial research is focused on finding ways to either remove or counteract the effects of mtDNA mutations with the hope of extending the human health- and lifespan. This review summarizes the current knowledge regarding the formation of mtDNA mutations and their impact on mitochondrial function. We also critically discuss proposed pathways interlinked with mammalian mtDNA mutations and suggest future research strategies to elucidate the role of mtDNA mutations in aging.
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Affiliation(s)
- Timo E S Kauppila
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, D-50931 Cologne, Germany
| | - Johanna H K Kauppila
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, D-50931 Cologne, Germany
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, D-50931 Cologne, Germany; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden.
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Margolis LM, Rivas DA, Berrone M, Ezzyat Y, Young AJ, McClung JP, Fielding RA, Pasiakos SM. Prolonged Calorie Restriction Downregulates Skeletal Muscle mTORC1 Signaling Independent of Dietary Protein Intake and Associated microRNA Expression. Front Physiol 2016; 7:445. [PMID: 27761114 PMCID: PMC5050214 DOI: 10.3389/fphys.2016.00445] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 09/20/2016] [Indexed: 01/18/2023] Open
Abstract
Short-term (5-10 days) calorie restriction (CR) downregulates muscle protein synthesis, with consumption of a high protein-based diet attenuating this decline. Benefit of increase protein intake is believed to be due to maintenance of amino acid-mediated anabolic signaling through the mechanistic target of rapamycin complex 1 (mTORC1), however, there is limited evidence to support this contention. The purpose of this investigation was to determine the effects of prolonged CR and high protein diets on skeletal muscle mTORC1 signaling and expression of associated microRNA (miR). Twelve-week old male Sprague Dawley rats consumed ad libitum (AL) or calorie restricted (CR; 40%) adequate (10%, AIN-93M) or high (32%) protein milk-based diets for 16 weeks. Body composition was determined using dual energy X-ray absorptiometry and muscle protein content was calculated from muscle homogenate protein concentrations expressed relative to fat-free mass to estimate protein content. Western blot and RT-qPCR were used to determine mTORC1 signaling and mRNA and miR expression in fasted mixed gastrocnemius. Independent of dietary protein intake, muscle protein content was 38% lower (P < 0.05) in CR compared to AL. Phosphorylation and total Akt, mTOR, rpS6, and p70S6K were lower (P < 0.05) in CR vs. AL, and total rpS6 was associated with muscle protein content (r = 0.64, r2 = 0.36). Skeletal muscle miR expression was not altered by either energy or protein intake. This study provides evidence that chronic CR attenuates muscle protein content by downregulating mTORC1 signaling. This response is independent of skeletal muscle miR and dietary protein.
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Affiliation(s)
- Lee M Margolis
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, U.S. Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts UniversityBoston, MA, USA; Military Nutrition Division, US Army Research Institute of Environmental MedicineNatick, MA, USA
| | - Donato A Rivas
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, U.S. Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University Boston, MA, USA
| | - Maria Berrone
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, U.S. Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University Boston, MA, USA
| | - Yassine Ezzyat
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, U.S. Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University Boston, MA, USA
| | - Andrew J Young
- Military Nutrition Division, US Army Research Institute of Environmental Medicine Natick, MA, USA
| | - James P McClung
- Military Nutrition Division, US Army Research Institute of Environmental Medicine Natick, MA, USA
| | - Roger A Fielding
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, U.S. Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University Boston, MA, USA
| | - Stefan M Pasiakos
- Military Nutrition Division, US Army Research Institute of Environmental Medicine Natick, MA, USA
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Hepple RT. Impact of aging on mitochondrial function in cardiac and skeletal muscle. Free Radic Biol Med 2016; 98:177-186. [PMID: 27033952 DOI: 10.1016/j.freeradbiomed.2016.03.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/12/2016] [Indexed: 12/13/2022]
Abstract
Both skeletal muscle and cardiac muscle are subject to marked structural and functional impairment with aging and these changes contribute to the reduced capacity for exercise as we age. Since mitochondria are involved in multiple aspects of cellular homeostasis including energetics, reactive oxygen species signaling, and regulation of intrinsic apoptotic pathways, defects in this organelle are frequently implicated in the deterioration of skeletal and cardiac muscle with aging. On this basis, the purpose of this review is to evaluate the evidence that aging causes dysfunction in mitochondria in striated muscle with a view towards drawing conclusions about the potential of these changes to contribute to the deterioration seen in striated muscle with aging. As will be shown, impairment in respiration and reactive oxygen species emission with aging are highly variable between studies and seem to be largely a consequence of physical inactivity. On the other hand, both skeletal and cardiac muscle mitochondria are more susceptible to permeability transition and this seems a likely cause of the increased recruitment of mitochondrial-mediated pathways of apoptosis seen in striated muscle. The review concludes by examining the role of degeneration of mitochondrial DNA versus impaired mitochondrial quality control mechanisms in the accumulation of mitochondria that are sensitized to permeability transition, whereby the latter mechanism is favored as the most likely cause.
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Affiliation(s)
- R T Hepple
- Department of Kinesiology, Centre for Translational Biology, McGill University Health Center, Canada; Meakins Christie Laboratories, Canada; Department of Medicine, McGill University, Canada
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Kitaoka Y, Nakazato K, Ogasawara R. Combined effects of resistance training and calorie restriction on mitochondrial fusion and fission proteins in rat skeletal muscle. J Appl Physiol (1985) 2016; 121:806-810. [PMID: 27539498 DOI: 10.1152/japplphysiol.00465.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/12/2016] [Indexed: 02/04/2023] Open
Abstract
Recent studies have demonstrated that resistance exercise leads not only to muscle hypertrophy, but it also improves mitochondrial function. Because calorie restriction (CR) has been suggested as a way to induce mitochondrial biogenesis, we examined the effects of resistance training with or without CR on muscle weight and key mitochondrial parameters in rat skeletal muscle. Four weeks of resistance training (thrice/wk) resulted in increased gastrocnemius muscle weight by 14% in rats fed ad libitum (AL). The degree of muscle-weight increase via resistance training was lower in rats with CR (7.4%). CR showed no effect on phosphorylation of mammalian target of rapamycin (mTOR) signaling proteins rpS6 and ULK1. Our results revealed that CR resulted in elevated levels of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) protein, a known master regulator of mitochondrial biogenesis. Resistance training alone also resulted in increased PGC-1α levels in skeletal muscle. The magnitude of the increase in PGC-1α was similar in rats in both the CR and AL groups. Moreover, we found that resistance training with CR resulted in elevated levels of proteins involved in mitochondrial fusion (Opa1 and Mfn1), and oxidative phosphorylation, whereas there was no effect of CR on the fission-regulatory proteins Fis1 and Drp1. These results indicate that CR attenuates resistance training-induced muscle hypertrophy, and that it may enhance mitochondrial adaptations in skeletal muscle.
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Affiliation(s)
- Yu Kitaoka
- Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan; and
| | - Riki Ogasawara
- Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan; Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
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Unravelling the mechanisms regulating muscle mitochondrial biogenesis. Biochem J 2016; 473:2295-314. [DOI: 10.1042/bcj20160009] [Citation(s) in RCA: 350] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
Abstract
Skeletal muscle is a tissue with a low mitochondrial content under basal conditions, but it is responsive to acute increases in contractile activity patterns (i.e. exercise) which initiate the signalling of a compensatory response, leading to the biogenesis of mitochondria and improved organelle function. Exercise also promotes the degradation of poorly functioning mitochondria (i.e. mitophagy), thereby accelerating mitochondrial turnover, and preserving a pool of healthy organelles. In contrast, muscle disuse, as well as the aging process, are associated with reduced mitochondrial quality and quantity in muscle. This has strong negative implications for whole-body metabolic health and the preservation of muscle mass. A number of traditional, as well as novel regulatory pathways exist in muscle that control both biogenesis and mitophagy. Interestingly, although the ablation of single regulatory transcription factors within these pathways often leads to a reduction in the basal mitochondrial content of muscle, this can invariably be overcome with exercise, signifying that exercise activates a multitude of pathways which can respond to restore mitochondrial health. This knowledge, along with growing realization that pharmacological agents can also promote mitochondrial health independently of exercise, leads to an optimistic outlook in which the maintenance of mitochondrial and whole-body metabolic health can be achieved by taking advantage of the broad benefits of exercise, along with the potential specificity of drug action.
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Simmons E, Fluckey JD, Riechman SE. Cumulative Muscle Protein Synthesis and Protein Intake Requirements. Annu Rev Nutr 2016; 36:17-43. [PMID: 27215586 DOI: 10.1146/annurev-nutr-071813-105549] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Muscle protein synthesis (MPS) fluctuates widely over the course of a day and is influenced by many factors. The time course of MPS responses to exercise and the influence of training and nutrition can only be pieced together from several different investigations and methods, many of which create unnatural experimental conditions. Measurements of cumulative MPS, the sum synthesis over an extended period, using deuterium oxide have been shown to accurately reflect muscle responses and may allow investigations of the response to exercise, total protein intake requirements, and interaction with protein timing in free-living experimental conditions; these factors have yet to be carefully integrated. Such studies could include clinical and athletic populations to integrate nutritional and exercise recommendations and help guide their revisions to optimize the skeletal muscle function that is so important to overall health.
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Affiliation(s)
- Erin Simmons
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843; ,
| | - James D Fluckey
- Department of Health and Kinesiology, Texas A&M University, College Station, Texas 77843;
| | - Steven E Riechman
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843; , .,Department of Health and Kinesiology, Texas A&M University, College Station, Texas 77843;
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64
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López-Lluch G, Navas P. Calorie restriction as an intervention in ageing. J Physiol 2016; 594:2043-60. [PMID: 26607973 PMCID: PMC4834802 DOI: 10.1113/jp270543] [Citation(s) in RCA: 170] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 11/21/2015] [Indexed: 12/20/2022] Open
Abstract
Ageing causes loss of function in tissues and organs, is accompanied by a chronic inflammatory process and affects life- and healthspan. Calorie restriction (CR) is a non-genetic intervention that prevents age-associated diseases and extends longevity in most of the animal models studied so far. CR produces a pleiotropic effect and improves multiple metabolic pathways, generating benefits to the whole organism. Among the effects of CR, modulation of mitochondrial activity and a decrease in oxidative damage are two of the hallmarks. Oxidative damage is reduced by the induction of endogenous antioxidant systems and modulation of the peroxidability index in cell membranes. Mitochondrial activity changes are regulated by inhibition of IGF-1 and Target of Rapamycin (TOR)-dependent activities and activation of AMP-dependent kinase (AMPK) and the sirtuin family of proteins. The activity of PGC-1α and FoxO is regulated by these systems and is involved in mitochondria biogenesis, oxidative metabolism activity and mitochondrial turnover. The use of mimetics and the regulation of common factors have demonstrated that these molecular pathways are essential to explain the effect of CR in the organism. Finally, the anti-inflammatory effect of CR is an interesting emerging factor to be taken into consideration. In the present revision we focus on the general effect of CR and other mimetics in longevity, focusing especially on the cardiovascular system and skeletal muscle.
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Affiliation(s)
- Guillermo López-Lluch
- Universidad Pablo de Olavide, Centro Andaluz de Biología del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Carretera de Utrera km. 1, 41013, Sevilla, Spain
| | - Plácido Navas
- Universidad Pablo de Olavide, Centro Andaluz de Biología del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Carretera de Utrera km. 1, 41013, Sevilla, Spain
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65
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Jacobs RA, Lundby AKM, Fenk S, Gehrig S, Siebenmann C, Flück D, Kirk N, Hilty MP, Lundby C. Twenty-eight days of exposure to 3454 m increases mitochondrial volume density in human skeletal muscle. J Physiol 2015; 594:1151-66. [PMID: 26339730 DOI: 10.1113/jp271118] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/28/2015] [Indexed: 12/11/2022] Open
Abstract
The role of hypoxia on skeletal muscle mitochondria is controversial. Studies superimposing exercise training on hypoxic exposure demonstrate an increase in skeletal muscle mitochondrial volume density (Mito(VD)) over equivalent normoxic training. In contrast, reductions in both skeletal muscle mass and Mito(VD) have been reported following mountaineering expeditions. These observations may, however, be confounded by negative energy balance, which may obscure the results. Accordingly we sought to examine the effects of high altitude hypoxic exposure on mitochondrial characteristics, with emphasis on Mito(VD), while minimizing changes in energy balance. For this purpose, skeletal muscle biopsies were obtained from nine lowlanders at sea level (Pre) and following 7 and 28 days of exposure to 3454 m. Maximal ergometer power output, whole body weight and composition, leg lean mass and skeletal muscle fibre area all remained unchanged following the altitude exposure. Transmission electron microscopy determined that intermyofibrillar (IMF) Mito(VD) was augmented (P = 0.028) by 11.5 ± 9.2% from Pre (5.05 ± 0.9%) to 28 Days (5.61 ± 0.04%). In contrast, there was no change in subsarcolemmal (SS) Mito(VD). As a result, total Mito(VD) (IMF + SS) was increased (P = 0.031) from 6.20 ± 1.5% at Pre to 6.62 ± 1.4% at 28 Days (7.8 ± 9.3%). At the same time no changes in mass-specific respiratory capacities, mitochondrial protein or antioxidant content were found. This study demonstrates that skeletal muscle Mito(VD) may increase with 28 days acclimation to 3454 m.
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Affiliation(s)
- Robert A Jacobs
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland.,Health and Physical Education, School of Teaching and Learning, Western Carolina University, Cullowhee, NC, USA.,Physical Therapy Department, Western Carolina University, Cullowhee, NC, USA
| | | | - Simone Fenk
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | - Saskia Gehrig
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | - Christoph Siebenmann
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland.,Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Solna, Sweden
| | - Daniela Flück
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | - Niels Kirk
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | | | - Carsten Lundby
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
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66
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Abstract
AbstractEnergy restriction (ER; also known as caloric restriction) is the only nutritional intervention that has repeatedly been shown to increase lifespan in model organisms and may delay ageing in humans. In the present review we discuss current scientific literature on ER and its molecular, metabolic and hormonal effects. Moreover, criteria for the classification of substances that might induce positive ER-like changes without having to reduce energy intake are summarised. Additionally, the putative ER mimetics (ERM) 2-deoxy-d-glucose, metformin, rapamycin, resveratrol, spermidine and lipoic acid and their suggested molecular targets are discussed. While there are reports on these ERM candidates that describe lifespan extension in model organisms, data on longevity-inducing effects in higher organisms such as mice remain controversial or are missing. Furthermore, some of these candidates produce detrimental side effects such as immunosuppression or lactic acidosis, or have not been tested for safety in long-term studies. Up to now, there are no known ERM that could be recommended without limitations for use in humans.
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67
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Quarles EK, Dai DF, Tocchi A, Basisty N, Gitari L, Rabinovitch PS. Quality control systems in cardiac aging. Ageing Res Rev 2015; 23:101-15. [PMID: 25702865 PMCID: PMC4686341 DOI: 10.1016/j.arr.2015.02.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 02/02/2015] [Accepted: 02/12/2015] [Indexed: 12/31/2022]
Abstract
Cardiac aging is an intrinsic process that results in impaired cardiac function, along with cellular and molecular changes. These degenerative changes are intimately associated with quality control mechanisms. This review provides a general overview of the clinical and cellular changes which manifest in cardiac aging, and the quality control mechanisms involved in maintaining homeostasis and retarding aging. These mechanisms include autophagy, ubiquitin-mediated turnover, apoptosis, mitochondrial quality control and cardiac matrix homeostasis. Finally, we discuss aging interventions that have been observed to impact cardiac health outcomes. These include caloric restriction, rapamycin, resveratrol, GDF11, mitochondrial antioxidants and cardiolipin-targeted therapeutics. A greater understanding of the quality control mechanisms that promote cardiac homeostasis will help to understand the benefits of these interventions, and hopefully lead to further improved therapeutic modalities.
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Affiliation(s)
- Ellen K Quarles
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, United States.
| | - Dao-Fu Dai
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, United States.
| | - Autumn Tocchi
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, United States.
| | - Nathan Basisty
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, United States.
| | - Lemuel Gitari
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, United States.
| | - Peter S Rabinovitch
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, United States.
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68
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Brook MS, Wilkinson DJ, Smith K, Atherton PJ. The metabolic and temporal basis of muscle hypertrophy in response to resistance exercise. Eur J Sport Sci 2015; 16:633-44. [PMID: 26289597 DOI: 10.1080/17461391.2015.1073362] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Constituting ∼40% of body mass, skeletal muscle has essential locomotory and metabolic functions. As such, an insight into the control of muscle mass is of great importance for maintaining health and quality-of-life into older age, under conditions of cachectic disease and with rehabilitation. In healthy weight-bearing individuals, muscle mass is maintained by the equilibrium between muscle protein synthesis (MPS) and muscle protein breakdown; when this balance tips in favour of MPS hypertrophy occurs. Despite considerable research into pharmacological/nutraceutical interventions, resistance exercise training (RE-T) remains the most potent stimulator of MPS and hypertrophy (in the majority of individuals). However, the mechanism(s) and time course of hypertrophic responses to RE-T remain poorly understood. We would suggest that available data are very much in favour of the notion that the majority of hypertrophy occurs in the early phases of RE-T (though still controversial to some) and that, for the most part, continued gains are hard to come by. Whilst the mechanisms of muscle hypertrophy represent the culmination of mechanical, auto/paracrine and endocrine events, the measurement of MPS remains a cornerstone for understanding the control of hypertrophy - mainly because it is the underlying driving force behind skeletal muscle hypertrophy. Development of sophisticated isotopic techniques (i.e. deuterium oxide) that lend to longer term insight into the control of hypertrophy by sustained RE-T will be paramount in providing insights into the metabolic and temporal regulation of hypertrophy. Such technologies will have broad application in muscle mass intervention for both athletes and for mitigating disease/age-related cachexia and sarcopenia, alike.
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Affiliation(s)
- Matthew S Brook
- a MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology , University of Nottingham , UK
| | - Daniel J Wilkinson
- a MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology , University of Nottingham , UK
| | - Kenneth Smith
- a MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology , University of Nottingham , UK
| | - Philip J Atherton
- a MRC-ARUK Centre of Excellence for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular Physiology , University of Nottingham , UK
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69
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Tocchi A, Quarles EK, Basisty N, Gitari L, Rabinovitch PS. Mitochondrial dysfunction in cardiac aging. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1424-33. [PMID: 26191650 DOI: 10.1016/j.bbabio.2015.07.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/06/2015] [Accepted: 07/09/2015] [Indexed: 02/07/2023]
Abstract
Cardiovascular diseases are the leading cause of death in most developed nations. While it has received the least public attention, aging is the dominant risk factor for developing cardiovascular diseases, as the prevalence of cardiovascular diseases increases dramatically with increasing age. Cardiac aging is an intrinsic process that results in impaired cardiac function, along with cellular and molecular changes. Mitochondria play a great role in these processes, as cardiac function is an energetically demanding process. In this review, we examine mitochondrial dysfunction in cardiac aging. Recent research has demonstrated that mitochondrial dysfunction can disrupt morphology, signaling pathways, and protein interactions; conversely, mitochondrial homeostasis is maintained by mechanisms that include fission/fusion, autophagy, and unfolded protein responses. Finally, we describe some of the recent findings in mitochondrial targeted treatments to help meet the challenges of mitochondrial dysfunction in aging.
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Affiliation(s)
- Autumn Tocchi
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Ellen K Quarles
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Nathan Basisty
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Lemuel Gitari
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
| | - Peter S Rabinovitch
- University of Washington School of Medicine, Department of Pathology, Box 357470, Seattle, WA 98195-7470, USA.
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70
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Drake JC, Bruns DR, Peelor FF, Biela LM, Miller RA, Miller BF, Hamilton KL. Long-lived Snell dwarf mice display increased proteostatic mechanisms that are not dependent on decreased mTORC1 activity. Aging Cell 2015; 14:474-82. [PMID: 25720574 PMCID: PMC4406676 DOI: 10.1111/acel.12329] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2015] [Indexed: 12/02/2022] Open
Abstract
Maintaining proteostasis is thought to be a key factor in slowed aging. In several growth-restricted models of long-life, we have shown evidence of increased proteostatic mechanisms, suggesting that proteostasis may be a shared characteristic of slowed aging. The Snell dwarf mouse is generated through the mutation of the Pit-1 locus causing reductions in multiple hormonal growth factors and mTORC1 signaling. Snell dwarfs are one of the longest lived rodent models of slowed aging. We hypothesized that proteostatic mechanisms would be increased in Snell compared to control (Con) as in other models of slowed aging. Using D2O, we simultaneously assessed protein synthesis in multiple subcellular fractions along with DNA synthesis in skeletal muscle, heart, and liver over 2 weeks in both sexes. We also assessed mTORC1-substrate phosphorylation. Skeletal muscle protein synthesis was decreased in all protein fractions of Snell compared to Con, varied by fraction in heart, and was not different between groups in liver. DNA synthesis was lower in Snell skeletal muscle and heart but not in liver when compared to Con. The new protein to new DNA synthesis ratio was increased threefold in Snell skeletal muscle and heart compared to Con. Snell mTORC1-substrate phosphorylation was decreased only in heart and liver. No effect of sex was seen in this study. Together with our previous investigations in long-lived models, we provide evidence further supporting proteostasis as a shared characteristic of slowed aging and show that increased proteostatic mechanisms may not necessarily require a decrease in mTORC1.
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Affiliation(s)
- Joshua C. Drake
- Health and Exercise Science Department Colorado State University 220 Moby B ComplexFort Collins CO 80523‐1582USA
| | - Danielle R. Bruns
- Health and Exercise Science Department Colorado State University 220 Moby B ComplexFort Collins CO 80523‐1582USA
| | - Frederick F. Peelor
- Health and Exercise Science Department Colorado State University 220 Moby B ComplexFort Collins CO 80523‐1582USA
| | - Laurie M. Biela
- Health and Exercise Science Department Colorado State University 220 Moby B ComplexFort Collins CO 80523‐1582USA
| | - Richard A. Miller
- Department of Pathology and Geriatrics Center University of Michigan 109 Zina Pitcher PlaceAnn Arbor MI 48109‐2200USA
| | - Benjamin F. Miller
- Health and Exercise Science Department Colorado State University 220 Moby B ComplexFort Collins CO 80523‐1582USA
| | - Karyn L. Hamilton
- Health and Exercise Science Department Colorado State University 220 Moby B ComplexFort Collins CO 80523‐1582USA
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71
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Barreiro E, Sznajder JI, Nader GA, Budinger GRS. Muscle dysfunction in patients with lung diseases: a growing epidemic. Am J Respir Crit Care Med 2015; 191:616-9. [PMID: 25767924 DOI: 10.1164/rccm.201412-2189oe] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Esther Barreiro
- 1 Respiratory Medicine Department-Lung Cancer Research Group, Institute of Medical Research of Hospital del Mar (IMIM)-Hospital del Mar, Parc de Salut Mar, Barcelona Biomedical Research Park, Barcelona, Spain
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72
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Ruetenik A, Barrientos A. Dietary restriction, mitochondrial function and aging: from yeast to humans. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1434-47. [PMID: 25979234 DOI: 10.1016/j.bbabio.2015.05.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/30/2015] [Accepted: 05/05/2015] [Indexed: 12/20/2022]
Abstract
Dietary restriction (DR) attenuates many detrimental effects of aging and consequently promotes health and increases longevity across organisms. While over the last 15 years extensive research has been devoted towards understanding the biology of aging, the precise mechanistic aspects of DR are yet to be settled. Abundant experimental evidence indicates that the DR effect on stimulating health impinges several metabolic and stress-resistance pathways. Downstream effects of these pathways include a reduction in cellular damage induced by oxidative stress, enhanced efficiency of mitochondrial functions and maintenance of mitochondrial dynamics and quality control, thereby attenuating age-related declines in mitochondrial function. However, the literature also accumulates conflicting evidence regarding how DR ameliorates mitochondrial performance and whether that is enough to slow age-dependent cellular and organismal deterioration. Here, we will summarize the current knowledge about how and to which extent the influence of different DR regimes on mitochondrial biogenesis and function contribute to postpone the detrimental effects of aging on health-span and lifespan. This article is part of a Special Issue entitled: Mitochondrial Dysfunction in Aging.
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Affiliation(s)
| | - Antoni Barrientos
- Neuroscience Graduate Program; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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73
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The pleiotropic effect of physical exercise on mitochondrial dynamics in aging skeletal muscle. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:917085. [PMID: 25945152 PMCID: PMC4402202 DOI: 10.1155/2015/917085] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/18/2015] [Indexed: 12/25/2022]
Abstract
Decline in human muscle mass and strength (sarcopenia) is one of the principal hallmarks of the aging process. Regular physical exercise and training programs are certain powerful stimuli to attenuate the physiological skeletal muscle alterations occurring during aging and contribute to promote health and well-being. Although the series of events that led to these muscle adaptations are poorly understood, the mechanisms that regulate these processes involve the “quality” of skeletal muscle mitochondria. Aerobic/endurance exercise helps to maintain and improve cardiovascular fitness and respiratory function, whereas strength/resistance-exercise programs increase muscle strength, power development, and function. Due to the different effect of both exercises in improving mitochondrial content and quality, in terms of biogenesis, dynamics, turnover, and genotype, combined physical activity programs should be individually prescribed to maximize the antiaging effects of exercise.
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74
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Lau E, Huang D, Cao Q, Dincer TU, Black CM, Lin AJ, Lee JM, Wang D, Liem DA, Lam MP, Ping P. Spatial and temporal dynamics of the cardiac mitochondrial proteome. Expert Rev Proteomics 2015; 12:133-46. [PMID: 25752359 PMCID: PMC4721584 DOI: 10.1586/14789450.2015.1024227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondrial proteins alter in their composition and quantity drastically through time and space in correspondence to changing energy demands and cellular signaling events. The integrity and permutations of this dynamism are increasingly recognized to impact the functions of the cardiac proteome in health and disease. This article provides an overview on recent advances in defining the spatial and temporal dynamics of mitochondrial proteins in the heart. Proteomics techniques to characterize dynamics on a proteome scale are reviewed and the physiological consequences of altered mitochondrial protein dynamics are discussed. Lastly, we offer our perspectives on the unmet challenges in translating mitochondrial dynamics markers into the clinic.
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Affiliation(s)
- Edward Lau
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Derrick Huang
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Quan Cao
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - T. Umut Dincer
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Caitie M. Black
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Amanda J. Lin
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Jessica M. Lee
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Ding Wang
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - David A. Liem
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Maggie P.Y. Lam
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Peipei Ping
- Departments of Physiology, The NHLBI Proteomics Center at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
- Departments of Medicine, and Bioinformatics, NIH Center of Excellence in Big Data Computing at UCLA, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
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75
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Wang D, Wu M, Li S, Gao Q, Zeng Q. Artemisinin mimics calorie restriction to extend yeast lifespan via a dual-phase mode: a conclusion drawn from global transcriptome profiling. SCIENCE CHINA-LIFE SCIENCES 2015; 58:451-65. [PMID: 25682392 DOI: 10.1007/s11427-014-4736-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 06/17/2014] [Indexed: 12/14/2022]
Abstract
Calorie restriction (CR) promotes longevity among distinct organisms from yeast to mammals. Although CR-prolonged lifespan is believed to associate with enhanced respiratory activity, it is apparently controversial for accelerated energy consumption regardless of insufficient nutrient intake. In reconciling the contradiction of less food supply versus much metabolite dispense, we revealed a CR-based mode of dual-phase responses that encompass a phase of mitochondrial enhancement (ME) and a phase of post-mitochondrial enhancement (PME), which can be distinguished by the expression patterns and activity dynamics of mitochondrial signatures. ME is characterized by global antioxidative activation, and PME is denoted by systemic metabolic modulation. CR-mediated aging-delaying effects are replicated by artesunate, a semi-synthetic derivative of the antimalarial artemisinin that can alkylate heme-containing proteins, suggesting artesunate-heme conjugation functionally resembles nitric oxide-heme interaction. A correlation of artesunate-heme conjugation with cytochrome c oxidase activation has been established from adduct formation and activity alteration. Exogenous hydrogen peroxide also mimics CR to trigger antioxidant responses, affect signaling cascades, and alter respiratory rhythms, implying hydrogen peroxide is engaged in lifespan extension. Conclusively, artesunate mimics CR-triggered nitric oxide and hydrogen peroxide to induce antioxidative networks for scavenging reactive oxygen species and mitigating oxidative stress, thereby directing metabolic conversion from anabolism to catabolism, maintaining essential metabolic functionality, and extending life expectancy in yeast.
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Affiliation(s)
- DaTing Wang
- Tropical Medicine Institute, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
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76
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Valerio A, Nisoli E. Nitric oxide, interorganelle communication, and energy flow: a novel route to slow aging. Front Cell Dev Biol 2015; 3:6. [PMID: 25705617 PMCID: PMC4319459 DOI: 10.3389/fcell.2015.00006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/12/2015] [Indexed: 12/14/2022] Open
Abstract
The mitochondrial lifecycle (mitochondrial biogenesis, dynamics, and removal by mitophagy) is carefully orchestrated to ensure the efficient generation of cellular energy and to maintain reactive oxygen species (ROS) production within an optimal range for cellular health. Based on latest research, these processes largely depend on mitochondrial interactions with other cell organelles, so that the ER- and peroxisome-mitochondrial connections might intervene in the control of cellular energy flow. Damaged organelles are cleared by autophagic mechanisms to assure the quality and proper function of the intracellular organelle pool. Nitric oxide (NO) generated through the endothelial nitric oxide synthase (eNOS) acts a gas signaling mediator to promote mitochondrial biogenesis and bioenergetics, with a favorable impact in diverse chronic diseases of the elderly. Obesity, diabetes and aging share common pathophysiological mechanisms, including mitochondrial impairment and dysfunctional eNOS. Here we review the evidences that eNOS-dependent mitochondrial biogenesis and quality control, and possibly the complex interplay among cellular organelles, may be affected by metabolic diseases and the aging processes, contributing to reduce healthspan and lifespan. Drugs or nutrients able to sustain the eNOS-NO generating system might contribute to maintain organelle homeostasis and represent novel preventive and/or therapeutic approaches to chronic age-related diseases.
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Affiliation(s)
- Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
| | - Enzo Nisoli
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan Milan, Italy
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Miller BF, Ehrlicher SE, Drake JC, Peelor FF, Biela LM, Pratt-Phillips S, Davis M, Hamilton KL. Assessment of protein synthesis in highly aerobic canine species at the onset and during exercise training. J Appl Physiol (1985) 2015; 118:811-7. [PMID: 25614602 DOI: 10.1152/japplphysiol.00982.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/21/2015] [Indexed: 11/22/2022] Open
Abstract
Canis lupus familiaris, the domesticated dog, is capable of extreme endurance performance. The ability to perform sustained aerobic exercise is dependent on a well-developed mitochondrial reticulum. In this study we examined the cumulative muscle protein and DNA synthesis in groups of athletic dogs at the onset of an exercise training program and following a strenuous exercise training program. We hypothesized that both at the onset and during an exercise training program there would be greater mitochondrial protein synthesis rates compared with sedentary control with no difference in mixed or cytoplasmic protein synthesis rates. Protein synthetic rates of three protein fractions and DNA synthesis were determined over 1 wk using (2)H2O in competitive Alaskan Huskies and Labrador Retrievers trained for explosive device detection. Both groups of dogs had very high rates of skeletal muscle protein synthesis in the sedentary state [Alaskan Huskies: Mixed = 2.28 ± 0.12, cytoplasmic (Cyto) = 2.91 ± 0.10, and mitochondrial (Mito) = 2.62 ± 0.07; Labrador Retrievers: Mixed = 3.88 ± 0.37, Cyto = 3.85 ± 0.06, and Mito = 2.92 ± 0.20%/day]. Mitochondrial (Mito) protein synthesis rates did not increase at the onset of an exercise training program. Exercise-trained dogs maintained Mito protein synthesis during exercise training when mixed (Mixed) and cytosolic (Cyto) fractions decreased, and this coincided with a decrease in p-RpS6 but also a decrease in p-ACC signaling. Contrary to our hypothesis, canines did not have large increases in mitochondrial protein synthesis at the onset or during an exercise training program. However, dogs have a high rate of protein synthesis compared with humans that perhaps does not necessitate an extra increase in protein synthesis at the onset of aerobic exercise training.
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Affiliation(s)
- Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
| | - Sarah E Ehrlicher
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Joshua C Drake
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Frederick F Peelor
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Laurie M Biela
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Shannon Pratt-Phillips
- Department of Animal Science, North Carolina State University, Raleigh, North Carolina; and
| | - Michael Davis
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
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78
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Miller BF, Wolff CA, Peelor FF, Shipman PD, Hamilton KL. Modeling the contribution of individual proteins to mixed skeletal muscle protein synthetic rates over increasing periods of label incorporation. J Appl Physiol (1985) 2015; 118:655-61. [PMID: 25593288 DOI: 10.1152/japplphysiol.00987.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Advances in stable isotope approaches, primarily the use of deuterium oxide ((2)H2O), allow for long-term measurements of protein synthesis, as well as the contribution of individual proteins to tissue measured protein synthesis rates. Here, we determined the influence of individual protein synthetic rates, individual protein content, and time of isotopic labeling on the measured synthesis rate of skeletal muscle proteins. To this end, we developed a mathematical model, applied the model to an established data set collected in vivo, and, to experimentally test the impact of different isotopic labeling periods, used (2)H2O to measure protein synthesis in cultured myotubes over periods of 2, 4, and 7 days. We first demonstrated the influence of both relative protein content and individual protein synthesis rates on measured synthesis rates over time. When expanded to include 286 individual proteins, the model closely approximated protein synthetic rates measured in vivo. The model revealed a 29% difference in measured synthesis rates from the slowest period of measurement (20 min) to the longest period of measurement (6 wk). In support of these findings, culturing of C2C12 myotubes with isotopic labeling periods of 2, 4, or 7 days revealed up to a doubling of the measured synthesis rate in the shorter labeling period compared with the longer period of labeling. From our model, we conclude that a 4-wk period of labeling is ideal for considering all proteins in a mixed-tissue fraction, while minimizing the slowing effect of fully turned-over proteins. In addition, we advocate that careful consideration must be paid to the period of isotopic labeling when comparing mixed protein synthetic rates between studies.
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Affiliation(s)
- Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; and
| | - Christopher A Wolff
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; and
| | - Fredrick F Peelor
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; and
| | - Patrick D Shipman
- Department of Mathematics, Colorado State University, Fort Collins, Colorado
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; and
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79
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Bruns DR, Brown RD, Stenmark KR, Buttrick PM, Walker LA. Mitochondrial integrity in a neonatal bovine model of right ventricular dysfunction. Am J Physiol Lung Cell Mol Physiol 2015; 308:L158-67. [PMID: 25416385 PMCID: PMC4338944 DOI: 10.1152/ajplung.00270.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/17/2014] [Indexed: 11/22/2022] Open
Abstract
Right ventricular (RV) function is a key determinant of survival in patients with both RV and left ventricular (LV) failure, yet the mechanisms of RV failure are poorly understood. Recent studies suggest cardiac metabolism is altered in RV failure in pulmonary hypertension (PH). Accordingly, we assessed mitochondrial content, dynamics, and function in hearts from neonatal calves exposed to hypobaric hypoxia (HH). This model develops severe PH with concomitant RV hypertrophy, dilation, and dysfunction. After 2 wk of HH, pieces of RV and LV were obtained along with samples from age-matched controls. Comparison with control assesses the effect of hypoxia, whereas comparison between the LV and RV in HH assesses the additional impact of RV overload. Mitochondrial DNA was unchanged in HH, as was mitochondrial content as assessed by electron microscopy. Immunoblotting for electron transport chain subunits revealed a small increase in mitochondrial content in HH in both ventricles. Mitochondrial dynamics were largely unchanged. Activity of individual respiratory chain complexes was reduced (complex I) or unchanged (complex V) in HH. Key enzymes in the glycolysis pathway were upregulated in both HH ventricles, alongside upregulation of hypoxia-inducible factor-1α protein. Importantly, none of the changes in expression or activity were different between ventricles, suggesting the changes are in response to HH and not RV overload. Upregulation of glycolytic modulators without chamber-specific mitochondrial dysfunction suggests that mitochondrial capacity and activity are maintained at the onset of PH, and the early RV dysfunction in this model results from mechanisms independent of the mitochondria.
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Affiliation(s)
- Danielle R Bruns
- Department of Medicine, Cardiology, University of Colorado-Denver, Aurora, Colorado; and
| | - R Dale Brown
- Department of Pediatrics, University of Colorado-Denver, Aurora, Colorado
| | - Kurt R Stenmark
- Department of Pediatrics, University of Colorado-Denver, Aurora, Colorado
| | - Peter M Buttrick
- Department of Medicine, Cardiology, University of Colorado-Denver, Aurora, Colorado; and
| | - Lori A Walker
- Department of Medicine, Cardiology, University of Colorado-Denver, Aurora, Colorado; and
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80
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Chan XCY, Black CM, Lin AJ, Ping P, Lau E. Mitochondrial protein turnover: methods to measure turnover rates on a large scale. J Mol Cell Cardiol 2014; 78:54-61. [PMID: 25451168 DOI: 10.1016/j.yjmcc.2014.10.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 12/27/2022]
Abstract
Mitochondrial proteins carry out diverse cellular functions including ATP synthesis, ion homeostasis, cell death signaling, and fatty acid metabolism and biogenesis. Compromised mitochondrial quality control is implicated in various human disorders including cardiac diseases. Recently it has emerged that mitochondrial protein turnover can serve as an informative cellular parameter to characterize mitochondrial quality and uncover disease mechanisms. The turnover rate of a mitochondrial protein reflects its homeostasis and dynamics under the quality control systems acting on mitochondria at a particular cell state. This review article summarizes some recent advances and outstanding challenges for measuring the turnover rates of mitochondrial proteins in health and disease. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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Affiliation(s)
- X'avia C Y Chan
- The NHLBI Proteomics Center at UCLA, Los Angeles, CA 90095, USA; Department of Physiology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Caitlin M Black
- The NHLBI Proteomics Center at UCLA, Los Angeles, CA 90095, USA; Department of Physiology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Amanda J Lin
- The NHLBI Proteomics Center at UCLA, Los Angeles, CA 90095, USA; Department of Physiology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Peipei Ping
- The NHLBI Proteomics Center at UCLA, Los Angeles, CA 90095, USA; Department of Physiology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA; Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA; Department of Bioinformatics, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA.
| | - Edward Lau
- The NHLBI Proteomics Center at UCLA, Los Angeles, CA 90095, USA; Department of Physiology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA.
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81
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Drake JC, Bruns DR, Peelor FF, Biela LM, Miller RA, Hamilton KL, Miller BF. Long-lived crowded-litter mice have an age-dependent increase in protein synthesis to DNA synthesis ratio and mTORC1 substrate phosphorylation. Am J Physiol Endocrinol Metab 2014; 307:E813-21. [PMID: 25205819 PMCID: PMC4216950 DOI: 10.1152/ajpendo.00256.2014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Increasing mouse litter size [crowded litter (CL)] presumably imposes a transient nutrient stress during suckling and extends lifespan through unknown mechanisms. Chronic calorically restricted and rapamycin-treated mice have decreased DNA synthesis and mTOR complex 1 (mTORC1) signaling but maintained protein synthesis, suggesting maintenance of existing cellular structures. We hypothesized that CL would exhibit similar synthetic and signaling responses to other long-lived models and, by comparing synthesis of new protein to new DNA, that insight may be gained into the potential preservation of existing cellular structures in the CL model. Protein and DNA synthesis was assessed in gastroc complex, heart, and liver of 4- and 7-mo CL mice. We also examined mTORC1 signaling in 3- and 7-mo aged animals. Compared with controls, 4-mo CL had greater DNA synthesis in gastroc complex with no differences in protein synthesis or mTORC1 substrate phosphorylation across tissues. Seven-month CL had less DNA synthesis than controls in heart and greater protein synthesis and mTORC1 substrate phosphorylation across tissues. The increased new protein-to-new DNA synthesis ratio suggests that new proteins are synthesized more so in existing cells at 7 mo, differing from 4 mo, in CL vs. controls. We propose that, in CL, protein synthesis shifts from being directed toward new cells (4 mo) to maintenance of existing cellular structures (7 mo), independently of decreased mTORC1.
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Affiliation(s)
- Joshua C Drake
- Health and Exercise Science Department, Colorado State University, Fort Collins, Colorado; and
| | - Danielle R Bruns
- Health and Exercise Science Department, Colorado State University, Fort Collins, Colorado; and
| | - Frederick F Peelor
- Health and Exercise Science Department, Colorado State University, Fort Collins, Colorado; and
| | - Laurie M Biela
- Health and Exercise Science Department, Colorado State University, Fort Collins, Colorado; and
| | - Richard A Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, Michigan
| | - Karyn L Hamilton
- Health and Exercise Science Department, Colorado State University, Fort Collins, Colorado; and
| | - Benjamin F Miller
- Health and Exercise Science Department, Colorado State University, Fort Collins, Colorado; and
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82
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The measurement of protein synthesis for assessing proteostasis in studies of slowed aging. Ageing Res Rev 2014; 18:106-11. [PMID: 25283966 DOI: 10.1016/j.arr.2014.09.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/11/2014] [Accepted: 09/18/2014] [Indexed: 11/19/2022]
Abstract
Slowing the aging process can reduce the risk for multiple chronic diseases simultaneously. It is increasingly recognized that maintaining protein homeostasis (or proteostasis) is important for slowing the aging process. Since proteostasis is a dynamic process, monitoring it is not a simple task and requires use of appropriate methods. This review will introduce methods to assess protein and DNA synthesis using deuterium oxide (D2O), and how protein and DNA synthesis outcomes provide insight into proteostatic mechanisms. Finally, we provide a discussion on how these assessments of protein and DNA synthesis are "mechanistic" investigations and provide an appropriate framework for the further development of slowed aging treatments.
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83
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Scalzo RL, Peltonen GL, Binns SE, Shankaran M, Giordano GR, Hartley DA, Klochak AL, Lonac MC, Paris HLR, Szallar SE, Wood LM, Peelor FF, Holmes WE, Hellerstein MK, Bell C, Hamilton KL, Miller BF. Greater muscle protein synthesis and mitochondrial biogenesis in males compared with females during sprint interval training. FASEB J 2014; 28:2705-14. [DOI: 10.1096/fj.13-246595] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Rebecca L. Scalzo
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Garrett L. Peltonen
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Scott E. Binns
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | | | - Gregory R. Giordano
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Dylan A. Hartley
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Anna L. Klochak
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Mark C. Lonac
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Hunter L. R. Paris
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Steve E. Szallar
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Lacey M. Wood
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Frederick F. Peelor
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | | | - Marc K. Hellerstein
- KineMed, Inc.EmeryvilleCaliforniaUSA
- Department of Nutritional Sciences and ToxicologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Christopher Bell
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Karyn L. Hamilton
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Benjamin F. Miller
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
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84
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Wilkinson DJ, Franchi MV, Brook MS, Narici MV, Williams JP, Mitchell WK, Szewczyk NJ, Greenhaff PL, Atherton PJ, Smith K. A validation of the application of D(2)O stable isotope tracer techniques for monitoring day-to-day changes in muscle protein subfraction synthesis in humans. Am J Physiol Endocrinol Metab 2014; 306:E571-9. [PMID: 24381002 PMCID: PMC3948971 DOI: 10.1152/ajpendo.00650.2013] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Quantification of muscle protein synthesis (MPS) remains a cornerstone for understanding the control of muscle mass. Traditional [(13)C]amino acid tracer methodologies necessitate sustained bed rest and intravenous cannulation(s), restricting studies to ~12 h, and thus cannot holistically inform on diurnal MPS. This limits insight into the regulation of habitual muscle metabolism in health, aging, and disease while querying the utility of tracer techniques to predict the long-term efficacy of anabolic/anticatabolic interventions. We tested the efficacy of the D2O tracer for quantifying MPS over a period not feasible with (13)C tracers and too short to quantify changes in mass. Eight men (22 ± 3.5 yr) undertook one-legged resistance exercise over an 8-day period (4 × 8-10 repetitions, 80% 1RM every 2nd day, to yield "nonexercised" vs. "exercise" leg comparisons), with vastus lateralis biopsies taken bilaterally at 0, 2, 4, and 8 days. After day 0 biopsies, participants consumed a D2O bolus (150 ml, 70 atom%); saliva was collected daily. Fractional synthetic rates (FSRs) of myofibrillar (MyoPS), sarcoplasmic (SPS), and collagen (CPS) protein fractions were measured by GC-pyrolysis-IRMS and TC/EA-IRMS. Body water initially enriched at 0.16-0.24 APE decayed at ~0.009%/day. In the nonexercised leg, MyoPS was 1.45 ± 0.10, 1.47 ± 0.06, and 1.35 ± 0.07%/day at 0-2, 0-4, and 0-8 days, respectively (~0.05-0.06%/h). MyoPS was greater in the exercised leg (0-2 days: 1.97 ± 0.13%/day; 0-4 days: 1.96 ± 0.15%/day, P < 0.01; 0-8 days: 1.79 ± 0.12%/day, P < 0.05). CPS was slower than MyoPS but followed a similar pattern, with the exercised leg tending to yield greater FSRs (0-2 days: 1.14 ± 0.13 vs. 1.45 ± 0.15%/day; 0-4 days: 1.13 ± 0.07%/day vs. 1.47 ± 0.18%/day; 0-8 days: 1.03 ± 0.09%/day vs. 1.40 ± 0.11%/day). SPS remained unchanged. Therefore, D2O has unrivaled utility to quantify day-to-day MPS in humans and inform on short-term changes in anabolism and presumably catabolism alike.
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Affiliation(s)
- Daniel J Wilkinson
- Medical Research Council-Arthritis Research United Kingdom Centre of Excellence for Musculoskeletal Ageing Research, University of Nottingham, Metabolic and Molecular Physiology, Nottingham, United Kingdom
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85
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Demontis F, Piccirillo R, Goldberg AL, Perrimon N. Mechanisms of skeletal muscle aging: insights from Drosophila and mammalian models. Dis Model Mech 2013; 6:1339-52. [PMID: 24092876 PMCID: PMC3820258 DOI: 10.1242/dmm.012559] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A characteristic feature of aged humans and other mammals is the debilitating, progressive loss of skeletal muscle function and mass that is known as sarcopenia. Age-related muscle dysfunction occurs to an even greater extent during the relatively short lifespan of the fruit fly Drosophila melanogaster. Studies in model organisms indicate that sarcopenia is driven by a combination of muscle tissue extrinsic and intrinsic factors, and that it fundamentally differs from the rapid atrophy of muscles observed following disuse and fasting. Extrinsic changes in innervation, stem cell function and endocrine regulation of muscle homeostasis contribute to muscle aging. In addition, organelle dysfunction and compromised protein homeostasis are among the primary intrinsic causes. Some of these age-related changes can in turn contribute to the induction of compensatory stress responses that have a protective role during muscle aging. In this Review, we outline how studies in Drosophila and mammalian model organisms can each provide distinct advantages to facilitate the understanding of this complex multifactorial condition and how they can be used to identify suitable therapies.
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Affiliation(s)
- Fabio Demontis
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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86
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Guéant JL, Elakoum R, Ziegler O, Coelho D, Feigerlova E, Daval JL, Guéant-Rodriguez RM. Nutritional models of foetal programming and nutrigenomic and epigenomic dysregulations of fatty acid metabolism in the liver and heart. Pflugers Arch 2013; 466:833-50. [PMID: 23999818 DOI: 10.1007/s00424-013-1339-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/16/2013] [Accepted: 08/17/2013] [Indexed: 12/23/2022]
Abstract
Barker's concept of 'foetal programming' proposes that intrauterine growth restriction (IUGR) predicts complex metabolic diseases through relationships that may be further modified by the postnatal environment. Dietary restriction and deficit in methyl donors, folate, vitamin B12, and choline are used as experimental conditions of foetal programming as they lead to IUGR and decreased birth weight. Overfeeding and deficit in methyl donors increase central fat mass and lead to a dramatic increase of plasma free fatty acids (FFA) in offspring. Conversely, supplementing the mothers under protein restriction with folic acid reverses metabolic and epigenomic phenotypes of offspring. High-fat diet or methyl donor deficiency (MDD) during pregnancy and lactation produce liver steatosis and myocardium hypertrophy that result from increased import of FFA and impaired fatty acid β-oxidation, respectively. The underlying molecular mechanisms show dysregulations related with similar decreased expression and activity of sirtuin 1 (SIRT1) and hyperacetylation of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α). High-fat diet and overfeeding impair AMPK-dependent phosphorylation of PGC-1α, while MDD decreases PGC-1α methylation through decreased expression of PRMT1 and cellular level of S-adenosyl methionine. The visceral manifestations of metabolic syndrome are under the influence of endoplasmic reticulum (ER) stress in overnourished animal models. These mechanisms should also deserve attention in the foetal programming effects of MDD since vitamin B12 influences ER stress through impaired SIRT1 deacetylation of HSF1. Taken together, similarities and synergies of high-fat diet and MDD suggest, therefore, considering their consecutive or contemporary influence in the mechanisms of complex metabolic diseases.
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Affiliation(s)
- Jean-Louis Guéant
- Inserm U954, Nutrition-Genetics-Environmental Risk Exposure (N-GERE), University of Lorraine and University Hospital Center of Nancy, BP 184, 54511, Vandœuvre-lès-Nancy, France,
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87
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Dominy JE, Puigserver P. Mitochondrial biogenesis through activation of nuclear signaling proteins. Cold Spring Harb Perspect Biol 2013; 5:5/7/a015008. [PMID: 23818499 DOI: 10.1101/cshperspect.a015008] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The dynamics of mitochondrial biogenesis and function is a complex interplay of cellular and molecular processes that ultimately shape bioenergetics capacity. Mitochondrial mass, by itself, represents the net balance between rates of biogenesis and degradation. Mitochondrial biogenesis is dependent on different signaling cascades and transcriptional complexes that promote the formation and assembly of mitochondria--a process that is heavily dependent on timely and coordinated transcriptional control of genes encoding for mitochondrial proteins. In this article, we discuss the major signals and transcriptional complexes, programming mitochondrial biogenesis, and bioenergetic activity. This regulatory network represents a new therapeutic window into the treatment of the wide spectrum of mitochondrial and neurodegenerative diseases characterized by dysregulation of mitochondrial dynamics and bioenergetic deficiencies.
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Affiliation(s)
- John E Dominy
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02215, USA
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88
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Fleming TH, Theilen TM, Masania J, Wunderle M, Karimi J, Vittas S, Bernauer R, Bierhaus A, Rabbani N, Thornalley PJ, Kroll J, Tyedmers J, Nawrotzki R, Herzig S, Brownlee M, Nawroth PP. Aging-dependent reduction in glyoxalase 1 delays wound healing. Gerontology 2013; 59:427-37. [PMID: 23797271 DOI: 10.1159/000351628] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 04/22/2013] [Indexed: 11/19/2022] Open
Abstract
Methylglyoxal (MG), the major dicarbonyl substrate of the enzyme glyoxalase 1 (GLO1), is a reactive metabolite formed via glycolytic flux. Decreased GLO1 activity in situ has been shown to result in an accumulation of MG and increased formation of advanced glycation endproducts, both of which can accumulate during physiological aging and at an accelerated rate in diabetes and other chronic degenerative diseases. To determine the physiological consequences which result from elevated MG levels and the role of MG and GLO1 in aging, wound healing in young (≤12 weeks) and old (≥52 weeks) wild-type mice was studied. Old mice were found to have a significantly slower rate of wound healing compared to young mice (74.9 ± 2.2 vs. 55.4 ± 1.5% wound closure at day 6; 26% decrease; p < 0.0001). This was associated with decreases in GLO1 transcription, expression and activity. The importance of GLO1 was confirmed in mice by inhibition of GLO1. Direct application of MG to the wounds of young mice, decreased wound healing by 24% compared to untreated mice, whereas application of BSA modified minimally by MG had no effect. Treatment of either young or old mice with aminoguanidine, a scavenger of free MG, significantly increased wound closure by 16% (66.8 ± 1.6 vs. 77.2 ± 3.1%; p < 0.05) and 64% (40.4 ± 7.9 vs. 66.4 ± 5.2%; p < 0.05), respectively, by day 6. As a result of the aminoguanidine treatment, the overall rate of wound healing in the old mice was restored to the level observed in the young mice. These findings were confirmed in vitro, as MG reduced migration and proliferation of fibroblasts derived from young and old, wild-type mice. The data demonstrate that the balance between MG and age-dependent GLO1 downregulation contributes to delayed wound healing in old mice.
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Affiliation(s)
- Thomas H Fleming
- Department of Medicine I and Clinical Chemistry, University of Heidelberg, Heidelberg, Germany
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89
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Gesing A, Masternak MM, Lewinski A, Karbownik-Lewinska M, Kopchick JJ, Bartke A. Decreased levels of proapoptotic factors and increased key regulators of mitochondrial biogenesis constitute new potential beneficial features of long-lived growth hormone receptor gene-disrupted mice. J Gerontol A Biol Sci Med Sci 2013; 68:639-51. [PMID: 23197187 PMCID: PMC3708518 DOI: 10.1093/gerona/gls231] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 10/19/2012] [Indexed: 01/06/2023] Open
Abstract
Decreased somatotrophic signaling is among the most important mechanisms associated with extended longevity. Mice homozygous for the targeted disruption of the growth hormone (GH) receptor gene (GH receptor knockout; GHRKO) are obese and dwarf, are characterized by a reduced weight and body size, undetectable levels of GH receptor, high concentration of serum GH, and greatly reduced plasma levels of insulin and insulin-like growth factor-I, and are remarkably long lived. Recent results suggest new features of GHRKO mice that may positively affect longevity-decreased levels of proapoptotic factors and increased levels of key regulators of mitochondrial biogenesis. The alterations in levels of the proapoptotic factors and key regulators of mitochondrial biogenesis were not further improved by two other potential life-extending interventions-calorie restriction and visceral fat removal. This may attribute the primary role to GH resistance in the regulation of apoptosis and mitochondrial biogenesis in GHRKO mice in terms of increased life span.
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Affiliation(s)
- Adam Gesing
- Department of Oncological Endocrinology, Medical University of Lodz, Lodz, Poland.
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90
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Drake JC, Peelor FF, Biela LM, Watkins MK, Miller RA, Hamilton KL, Miller BF. Assessment of mitochondrial biogenesis and mTORC1 signaling during chronic rapamycin feeding in male and female mice. J Gerontol A Biol Sci Med Sci 2013; 68:1493-501. [PMID: 23657975 DOI: 10.1093/gerona/glt047] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chronic inhibition of the protein synthesis regulator mTORC1 through rapamycin extends life span in mice, with longer extension in females than in males. Whether rapamycin treatment inhibits protein synthesis or whether it does so differently between sexes has not been examined. UM-HET3 mice were fed a control or rapamycin-supplemented (Rap) diet for 12 weeks. Protein synthesis in mixed, cytosolic (cyto), and mitochondrial (mito) fractions and DNA synthesis and mTORC1 signaling were determined in skeletal muscle, heart, and liver. In both sexes, mito protein synthesis was maintained in skeletal muscle from Rap despite decreases in mixed and cyto fractions, DNA synthesis, and rpS6 phosphorylation. In the heart, no change in protein synthesis occurred despite the decreased DNA synthesis. In the heart and liver, Rap males were more sensitive to mTORC1 inhibition than Rap females. In conclusion, we show changes in protein synthesis and mTORC1 signaling that differ by sex and tissue.
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Affiliation(s)
- Joshua C Drake
- Department of Health and Exercise Science, Colorado State University, 220 Moby B Complex, Fort Collins, CO 80523-1582.
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91
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Johnson ML, Robinson MM, Nair KS. Skeletal muscle aging and the mitochondrion. Trends Endocrinol Metab 2013; 24:247-56. [PMID: 23375520 PMCID: PMC3641176 DOI: 10.1016/j.tem.2012.12.003] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 01/06/2023]
Abstract
Decline in human muscle mass and strength (sarcopenia) is a hallmark of the aging process. A growing body of research in the areas of bioenergetics and protein turnover has placed the mitochondria at the center of this process. It is now clear that, unless an active lifestyle is rigorously followed, skeletal muscle mitochondrial decline occurs as humans age. Increasing research on mitochondrial biology has elucidated the regulatory pathways involved in mitochondrial biogenesis, many of which are potential therapeutic targets, and highlight the beneficial effects of vigorous physical activity on skeletal muscle health for an aging population.
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Affiliation(s)
- Matthew L Johnson
- Mayo Clinic, Division of Endocrinology, 200 First Street SW, Joseph 5-194, Rochester, MN 55905, USA
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92
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Gouspillou G, Hepple RT. Facts and controversies in our understanding of how caloric restriction impacts the mitochondrion. Exp Gerontol 2013; 48:1075-84. [PMID: 23523973 DOI: 10.1016/j.exger.2013.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/26/2013] [Accepted: 03/11/2013] [Indexed: 12/11/2022]
Abstract
Caloric restriction (CR) has pronounced benefits in promoting healthy aging. Amongst the most frequently implicated physiological mechanisms implicated in this benefit is altered mitochondrial function. Whereas a reduction in mitochondrial reactive oxygen species (ROS) production is a widely consistent effect of CR, an increase in mitochondrial biogenesis, which is accepted by many as fact, is contradicted on several levels, most critically by a lack of increase in mitochondrial protein synthesis rate in vivo. Furthermore, an increase in PGC-1α protein and markers of mitochondrial content with CR is a highly variable observation between studies. On the other hand, deacetylation of several mitochondrial proteins by the sirtuin, Sirt3, is an increasingly reported observation and at least so far, this observation is consistent between studies. Notwithstanding this point, the controversies evident in the published literature underscore the significant questions that remain in our understanding of how CR impacts the mitochondrion and suggest we have yet to fully understand the complexities herein.
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Affiliation(s)
- Gilles Gouspillou
- McGill University Health Center, Department of Kinesiology, McGill University, Montreal, QC, Canada
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93
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Perše M, Injac R, Erman A. Oxidative status and lipofuscin accumulation in urothelial cells of bladder in aging mice. PLoS One 2013; 8:e59638. [PMID: 23527235 PMCID: PMC3603863 DOI: 10.1371/journal.pone.0059638] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 02/16/2013] [Indexed: 01/23/2023] Open
Abstract
Age-related changes in various tissues have been associated with the onset of a number of age-related diseases, including inflammation and cancer. Bladder cancer, for instance, is a disease that mainly afflicts middle-aged or elderly people and is mostly of urothelial origin. Although research on age-related changes of long-lived post-mitotic cells such as neurons is rapidly progressing, nothing is known about age-related changes in the urothelium of the urinary bladder, despite all the evidence confirming the important role of oxidative stress in urinary bladder pathology. The purpose of this study was thus to investigate the oxidative status and age-related changes in urothelial cells of the urinary bladder of young (2 months) and aging (20 months) mice by means of various methods. Our results demonstrated that healthy young urothelium possesses a powerful antioxidant defence system that functions as a strong defence barrier against reactive species. In contrast, urothelial cells of aging bladder show significantly decreased total antioxidant capacity and significantly increased levels of lipid peroxides (MDA) and iNOS, markers of oxidative stress. Our study demonstrates for the first time that ultrastructural alterations in mitochondria and accumulation of lipofuscin, known to be one of the aging pigments, can clearly be found in superficial urothelial cells of the urinary bladder in aging mice. Since the presence of lipofuscin in the urothelium has not yet been reported, we applied various methods to confirm our finding. Our results reveal changes in the oxidative status and structural alterations to superficial urothelial cells similar to those of other long-lived post-mitotic cells.
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Affiliation(s)
- Martina Perše
- Medical Experimental Centre, Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Rade Injac
- Institute of Pharmaceutical Biology, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Andreja Erman
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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94
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Dideriksen K, Reitelseder S, Holm L. Influence of amino acids, dietary protein, and physical activity on muscle mass development in humans. Nutrients 2013; 5:852-76. [PMID: 23486194 PMCID: PMC3705323 DOI: 10.3390/nu5030852] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/13/2013] [Accepted: 02/25/2013] [Indexed: 12/14/2022] Open
Abstract
Ingestion of protein is crucial for maintenance of a variety of body functions and within the scope of this review we will specifically focus on the regulation of skeletal muscle mass. A quantitative limitation exists as to how much muscle protein the body can synthesize in response to protein intake. Ingestion of excess protein exerts an unwanted load to the body and therefore, it is important to find the least amount of protein that provides the maximal hypertrophic stimulus. Hence, research has focused on revealing the relationship between protein intake (dose) and its resulting stimulation of muscle protein synthesis (response). In addition to the protein amount, the protein digestibility and, hence, the availability of its constituent amino acids is decisive for the response. In this regard, recent studies have provided in-depth knowledge about the time-course of the muscle protein synthetic response dependent on the characteristics of the protein ingested. The effect of protein intake on muscle protein accretion can further be stimulated by prior exercise training. In the ageing population, physical training may counteract the development of “anabolic resistance” and restore the beneficial effect of protein feeding. Presently, our knowledge is based on measures obtained in standardized experimental settings or during long-term intervention periods. However, to improve coherence between these types of data and to further improve our knowledge of the effects of protein ingestion, other investigative approaches than those presently used are requested.
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Affiliation(s)
- Kasper Dideriksen
- Institute of Sports Medicine, Department of Orthopedic Surgery M81, Bispebjerg Hospital, Bispebjerg Bakke 23, DK-2400 Copenhagen NV, Denmark; E-Mails: (S.R.); (L.H.)
- Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +45-3531-3948; Fax: +45-3531-2733
| | - Søren Reitelseder
- Institute of Sports Medicine, Department of Orthopedic Surgery M81, Bispebjerg Hospital, Bispebjerg Bakke 23, DK-2400 Copenhagen NV, Denmark; E-Mails: (S.R.); (L.H.)
- Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Lars Holm
- Institute of Sports Medicine, Department of Orthopedic Surgery M81, Bispebjerg Hospital, Bispebjerg Bakke 23, DK-2400 Copenhagen NV, Denmark; E-Mails: (S.R.); (L.H.)
- Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
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95
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Khraiwesh H, López-Domínguez JA, López-Lluch G, Navas P, de Cabo R, Ramsey JJ, Villalba JM, González-Reyes JA. Alterations of ultrastructural and fission/fusion markers in hepatocyte mitochondria from mice following calorie restriction with different dietary fats. J Gerontol A Biol Sci Med Sci 2013; 68:1023-34. [PMID: 23403066 DOI: 10.1093/gerona/glt006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We analyzed ultrastructural changes and markers of fission/fusion in hepatocyte mitochondria from mice submitted to 40% calorie restriction (CR) for 6 months versus ad-libitum-fed controls. To study the effects of dietary fat under CR, animals were separated into three CR groups with soybean oil (also in controls), fish oil, and lard. CR induced differential changes in hepatocyte and mitochondrial size, in the volume fraction occupied by mitochondria, and in the number of mitochondria per hepatocyte. The number of cristae per mitochondrion was significantly higher in all CR groups compared with controls. Proteins related to mitochondrial fission (Fis1 and Drp1) increased with CR, but no changes were detected in proteins involved in mitochondrial fusion (Mfn1, Mfn2, and OPA1). Although many of these changes could be attributed to CR regardless of dietary fat, changing membrane lipid composition by different fat sources did modulate the effects of CR on hepatocyte mitochondria.
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Affiliation(s)
- Husam Khraiwesh
- Departamento de Biologia Celular, Fisiologia e Inmunologia, Universidad de Cordoba, Campus de Excelencia Internacional Agroalimentario, ceiA3, Cordoba, Spain
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96
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Jacobs RA, Diaz V, Soldini L, Haider T, Thomassen M, Nordsborg NB, Gassmann M, Lundby C. Fast-Twitch Glycolytic Skeletal Muscle Is Predisposed to Age-Induced Impairments in Mitochondrial Function. J Gerontol A Biol Sci Med Sci 2013; 68:1010-22. [DOI: 10.1093/gerona/gls335] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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97
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Hebert AS, Dittenhafer-Reed KE, Yu W, Bailey DJ, Selen ES, Boersma MD, Carson JJ, Tonelli M, Balloon A, Higbee AJ, Westphall MS, Pagliarini DJ, Prolla TA, Assadi-Porter F, Roy S, Denu JM, Coon JJ. Calorie restriction and SIRT3 trigger global reprogramming of the mitochondrial protein acetylome. Mol Cell 2013; 49:186-99. [PMID: 23201123 PMCID: PMC3704155 DOI: 10.1016/j.molcel.2012.10.024] [Citation(s) in RCA: 500] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 09/11/2012] [Accepted: 10/23/2012] [Indexed: 12/18/2022]
Abstract
Calorie restriction (CR) extends life span in diverse species. Mitochondria play a key role in CR adaptation; however, the molecular details remain elusive. We developed and applied a quantitative mass spectrometry method to probe the liver mitochondrial acetyl-proteome during CR versus control diet in mice that were wild-type or lacked the protein deacetylase SIRT3. Quantification of 3,285 acetylation sites-2,193 from mitochondrial proteins-rendered a comprehensive atlas of the acetyl-proteome and enabled global site-specific, relative acetyl occupancy measurements between all four experimental conditions. Bioinformatic and biochemical analyses provided additional support for the effects of specific acetylation on mitochondrial protein function. Our results (1) reveal widespread reprogramming of mitochondrial protein acetylation in response to CR and SIRT3, (2) identify three biochemically distinct classes of acetylation sites, and (3) provide evidence that SIRT3 is a prominent regulator in CR adaptation by coordinately deacetylating proteins involved in diverse pathways of metabolism and mitochondrial maintenance.
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Affiliation(s)
- Alexander S. Hebert
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, United States
| | | | - Wei Yu
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Derek J. Bailey
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Ebru Selin Selen
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Melissa D. Boersma
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Joshua J. Carson
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison, University of Wisconsin, Madison, Wisconsin, United States
| | - Allison Balloon
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Alan J. Higbee
- Genome Center of Wisconsin, University of Wisconsin, Madison, Wisconsin, United States
| | - Michael S. Westphall
- Genome Center of Wisconsin, University of Wisconsin, Madison, Wisconsin, United States
| | - David J. Pagliarini
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Tomas A. Prolla
- Genetics and Medical Genetics, University of Wisconsin, Madison, Wisconsin, United States
| | - Fariba Assadi-Porter
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
- National Magnetic Resonance Facility at Madison, University of Wisconsin, Madison, Wisconsin, United States
| | - Sushmita Roy
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, Wisconsin, United States
| | - John M. Denu
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Joshua J. Coon
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, United States
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin, United States
- Genome Center of Wisconsin, University of Wisconsin, Madison, Wisconsin, United States
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98
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Lanza IR, Zabielski P, Klaus KA, Morse DM, Heppelmann CJ, Bergen HR, Dasari S, Walrand S, Short KR, Johnson ML, Robinson MM, Schimke JM, Jakaitis DR, Asmann YW, Sun Z, Nair KS. Chronic caloric restriction preserves mitochondrial function in senescence without increasing mitochondrial biogenesis. Cell Metab 2012; 16:777-88. [PMID: 23217257 PMCID: PMC3544078 DOI: 10.1016/j.cmet.2012.11.003] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 09/10/2012] [Accepted: 11/06/2012] [Indexed: 12/21/2022]
Abstract
Caloric restriction (CR) mitigates many detrimental effects of aging and prolongs life span. CR has been suggested to increase mitochondrial biogenesis, thereby attenuating age-related declines in mitochondrial function, a concept that is challenged by recent studies. Here we show that lifelong CR in mice prevents age-related loss of mitochondrial oxidative capacity and efficiency, measured in isolated mitochondria and permeabilized muscle fibers. We find that these beneficial effects of CR occur without increasing mitochondrial abundance. Whole-genome expression profiling and large-scale proteomic surveys revealed expression patterns inconsistent with increased mitochondrial biogenesis, which is further supported by lower mitochondrial protein synthesis with CR. We find that CR decreases oxidant emission, increases antioxidant scavenging, and minimizes oxidative damage to DNA and protein. These results demonstrate that CR preserves mitochondrial function by protecting the integrity and function of existing cellular components rather than by increasing mitochondrial biogenesis.
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Affiliation(s)
- Ian R Lanza
- Division of Endocrinology and Metabolism, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
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99
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Jacobs RA, Díaz V, Meinild AK, Gassmann M, Lundby C. The C57Bl/6 mouse serves as a suitable model of human skeletal muscle mitochondrial function. Exp Physiol 2012. [PMID: 23180810 DOI: 10.1113/expphysiol.2012.070037] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is debatable whether differences in mitochondrial function exist across skeletal muscle types and whether mouse skeletal muscle mitochondrial function can serve as a valid model for human skeletal muscle mitochondrial function. The aims of this study were to compare and contrast three different mouse skeletal muscles and to identify the mouse muscle that most closely resembles human skeletal muscle respiratory capacity and control. Mouse quadriceps (QUAD(M)), soleus (SOL(M)) and gastrocnemius (GAST(M)) skeletal muscles were obtained from 8- to 10-week-old healthy mice (n = 8), representing mixed, oxidative and glycolytic muscle, respectively. Skeletal muscle samples were also collected from young, active, healthy human subjects (n = 8) from the vastis lateralis (QUAD(H)). High-resolution respirometry was used to examine mitochondrial function in all skeletal muscle samples, and mitochondrial content was quantified with citrate synthase activity. Mass-specific respiration was higher across all respiratory states in SOL(M) versus both GAST(M) and QUAD(H) (P < 0.01). When controlling for mitochondrial content, however, SOL(M) respiration was lower than GAST(M) and QUAD(H) (P < 0.05 and P < 0.01, respectively). When comparing respiratory capacity between mouse and human muscle, QUAD(M) exhibited only one different respiratory state when compared with QUAD(H). These results demonstrate that qualitative differences in mitochondrial function exist between different mouse skeletal muscles types when respiratory capacity is normalized to mitochondrial content, and that skeletal muscle respiratory capacity in young, healthy QUAD(M) does correspond well with that of young, healthy QUAD(H).
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Affiliation(s)
- Robert A Jacobs
- Institute of Physiology and Zurich Center for Integrative Human Physiology, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
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100
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Miller BF, Robinson MM, Reuland DJ, Drake JC, Peelor FF, Bruss MD, Hellerstein MK, Hamilton KL. Calorie restriction does not increase short-term or long-term protein synthesis. J Gerontol A Biol Sci Med Sci 2012; 68:530-8. [PMID: 23105041 DOI: 10.1093/gerona/gls219] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Increased protein synthesis is proposed as a mechanism of life-span extension during caloric restriction (CR). We hypothesized that CR does not increase protein synthesis in all tissues and protein fractions and that any increased protein synthesis with CR would be due to an increased anabolic effect of feeding. We used short- (4 hours) and long-term (6 weeks) methods to measure in vivo protein synthesis in lifelong ad libitum (AL) and CR mice. We did not detect an acute effect of feeding on protein synthesis while liver mitochondrial protein synthesis was lower in CR mice versus AL mice. Mammalian target of rapamycin (mTOR) signaling was repressed in liver and heart from CR mice indicative of energetic stress and suppression of growth. Our main findings were that CR did not increase rates of mixed protein synthesis over the long term or in response to acute feeding, and protein synthesis was maintained despite decreased mTOR signaling.
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Affiliation(s)
- Benjamin F Miller
- Department of Health and Exercise Science, Colorado State University, Fort Collins CO 80523-1582, USA.
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