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O'Reilly CL, Bodine SC, Miller BF. Current limitations and future opportunities of tracer studies of muscle ageing. J Physiol 2023:10.1113/JP285616. [PMID: 38051758 PMCID: PMC11150331 DOI: 10.1113/jp285616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/22/2023] [Indexed: 12/07/2023] Open
Affiliation(s)
- Colleen L O'Reilly
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Sue C Bodine
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Oklahoma City Veterans Association, Oklahoma City, OK, USA
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Oklahoma City Veterans Association, Oklahoma City, OK, USA
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2
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Vardar Acar N, Özgül RK. A big picture of the mitochondria-mediated signals: From mitochondria to organism. Biochem Biophys Res Commun 2023; 678:45-61. [PMID: 37619311 DOI: 10.1016/j.bbrc.2023.08.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/02/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
Mitochondria, well-known for years as the powerhouse and biosynthetic center of the cell, are dynamic signaling organelles beyond their energy production and biosynthesis functions. The metabolic functions of mitochondria, playing an important role in various biological events both in physiological and stress conditions, transform them into important cellular stress sensors. Mitochondria constantly communicate with the rest of the cell and even from other cells to the organism, transmitting stress signals including oxidative and reductive stress or adaptive signals such as mitohormesis. Mitochondrial signal transduction has a vital function in regulating integrity of human genome, organelles, cells, and ultimately organism.
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Affiliation(s)
- Neşe Vardar Acar
- Department of Pediatric Metabolism, Institute of Child Health, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - R Köksal Özgül
- Department of Pediatric Metabolism, Institute of Child Health, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
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3
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Evaluation of the Combination of Metformin and Rapamycin in an MPP +-Treated SH-SY5Y Model of Parkinson's Disease. Adv Pharmacol Pharm Sci 2023; 2023:3830861. [PMID: 36698448 PMCID: PMC9870674 DOI: 10.1155/2023/3830861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 01/07/2023] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
Metformin (MET) and rapamycin (RAPA) have been reported to protect against neurodegeneration in cellular and animal models of Parkinson's disease (PD). MET, which is a first-line drug for type 2 diabetes, and RAPA are known as mTORC1 inhibitors. MET also acts as an AMPK activator, which leads to the inhibition of mTORC1 activity. mTORC1 is a downstream target of Akt signaling. Inactivation of Akt/mTORC1 and its downstream S6K1 can promote autophagy, a process involved in PD pathogenesis. Based on their mechanisms and potential benefits, we evaluated the potential protective effect of pretreatment with combinations of MET and RAPA in a 1-methyl-4-phenylpyridinium ion (MPP+)-treated SH-SY5Y neuronal cell model of PD. The results showed that MET and RAPA combinations lowered cell viability after exposure to MPP+. Increased LC3-II levels by MPP+ were not altered by MET and RAPA pretreatment. In normal neuronal cells, MET and RAPA pretreatment inhibited the phosphorylation of both Akt and S6K1, and the phosphorylation remained suppressed after MPP+ exposure. These findings suggest that when cells were exposed to MPP+, suppressed phosphorylation of both Akt and S6K1 by the MET and RAPA combination may lead to an inappropriate autophagic response, resulting in increased cell death.
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4
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Integrated or Independent Actions of Metformin in Target Tissues Underlying Its Current Use and New Possible Applications in the Endocrine and Metabolic Disorder Area. Int J Mol Sci 2021; 22:ijms222313068. [PMID: 34884872 PMCID: PMC8658259 DOI: 10.3390/ijms222313068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/18/2021] [Accepted: 11/29/2021] [Indexed: 12/14/2022] Open
Abstract
Metformin is considered the first-choice drug for type 2 diabetes treatment. Actually, pleiotropic effects of metformin have been recognized, and there is evidence that this drug may have a favorable impact on health beyond its glucose-lowering activity. In summary, despite its long history, metformin is still an attractive research opportunity in the field of endocrine and metabolic diseases, age-related diseases, and cancer. To this end, its mode of action in distinct cell types is still in dispute. The aim of this work was to review the current knowledge and recent findings on the molecular mechanisms underlying the pharmacological effects of metformin in the field of metabolic and endocrine pathologies, including some endocrine tumors. Metformin is believed to act through multiple pathways that can be interconnected or work independently. Moreover, metformin effects on target tissues may be either direct or indirect, which means secondary to the actions on other tissues and consequent alterations at systemic level. Finally, as to the direct actions of metformin at cellular level, the intracellular milieu cooperates to cause differential responses to the drug between distinct cell types, despite the primary molecular targets may be the same within cells. Cellular bioenergetics can be regarded as the primary target of metformin action. Metformin can perturb the cytosolic and mitochondrial NAD/NADH ratio and the ATP/AMP ratio within cells, thus affecting enzymatic activities and metabolic and signaling pathways which depend on redox- and energy balance. In this context, the possible link between pyruvate metabolism and metformin actions is extensively discussed.
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5
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Brown JL, Lawrence MM, Borowik A, Oliver L, Peelor FF, Van Remmen H, Miller BF. Tumor burden negatively impacts protein turnover as a proteostatic process in noncancerous liver, heart, and muscle, but not brain. J Appl Physiol (1985) 2021; 131:72-82. [PMID: 34013745 DOI: 10.1152/japplphysiol.01026.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cancer survivors are more susceptible to pathologies such as hypertension, liver disease, depression, and coronary artery disease when compared with individuals who have never been diagnosed with cancer. Therefore, it is important to understand how tumor burden negatively impacts nontumor-bearing tissues that may impact future disease susceptibility. We hypothesized that the energetic costs of a tumor would compromise proteostatic maintenance in other tissues. Therefore, the purpose of this study was to determine if tumor burden changes protein synthesis and proliferation rates in heart, brain, and liver. One million Lewis lung carcinoma (LLC) cells or phosphate-buffered saline (PBS, sham) were injected into the hind flank of female mice at ∼4.5 mo of age, and the tumor developed for 3 wk. Rates of proliferation and protein synthesis were measured in heart, brain, liver, and tumor tissue. Compared with sham, rates of protein synthesis (structural/nuclear, cytosolic, mitochondrial, and collagen) relative to proliferation were lower in the heart and liver of LLC mice, but higher in the brain of LLC mice. In the tumor tissue, the ratio of protein synthesis to DNA synthesis was approximately 1.0 showing that protein synthesis in the tumor was used for proliferation with little proteostatic maintenance. We further provide evidence that the differences in tissue responses may be due to energetic stress. We concluded that the decrease in proteostatic maintenance in liver, heart, and muscle might contribute to the increased risk of disease in cancer survivors.NEW & NOTEWORTHY We present data showing that simultaneously measuring protein synthesis and cell proliferation can help in the understanding of protein turnover as a proteostatic process in response to tumor burden. In some tissues, like hepatic, cardiac, and skeletal muscle, there was a decrease in the protein to DNA synthesis ratio indicating less proteostatic maintenance. In contrast, the brain maintained or even increased this protein to DNA synthesis ratio indicating more proteostatic maintenance.
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Affiliation(s)
- Jacob L Brown
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Marcus M Lawrence
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma.,Department of Kinesiology and Outdoor Recreation, Southern Utah University, Cedar City, Utah
| | - Agnieszka Borowik
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Lauren Oliver
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma.,Oklahoma University Health Science Center, Oklahoma City, Oklahoma
| | - Fredrick F Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Holly Van Remmen
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma.,Oklahoma City VA Medical Center, Oklahoma City, Oklahoma
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
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6
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Abbott CB, Lawrence MM, Kobak KA, Lopes EBP, Peelor FF, Donald EJ, Van Remmen H, Griffin TM, Miller BF. A Novel Stable Isotope Approach Demonstrates Surprising Degree of Age-Related Decline in Skeletal Muscle Collagen Proteostasis. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab028. [PMID: 34124684 PMCID: PMC8187230 DOI: 10.1093/function/zqab028] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/08/2021] [Accepted: 05/07/2021] [Indexed: 02/06/2023]
Abstract
Age-related deterioration in turnover of collagen proteins accelerates extracellular matrix fibrosis and hinders adaptation to external stimuli. This project sought to understand factors that increase skeletal muscle fibrosis with age by studying what we term the dynamic protein pool. We hypothesized that the dynamic protein pool size of muscle collagen decreases with age, thus indicating a decrease in proteostatic maintenance (ie, ability to maintain proteostasis), and that failure to account for these changes impacts the interpretation of tracer-measured synthesis rates. We used deuterium oxide (D2O) labeling for up to 60 days in adult (6 months) and old (23 months) mice. The dynamic protein pool in adult skeletal muscle was 65% in tibialis anterior (TA), but only 28% in gastrocnemius (Gastroc). In aged muscle, the dynamic protein pool was further decreased to only 35% and 14% for TA and Gastroc, respectively. We showed that this loss in dynamic pool size was associated with increases in markers of fibrosis and decreased proteostatic maintenance. We demonstrate that aged muscle has higher rates of collagen protein synthesis and lower rates of collagen protein breakdown, which causes collagen accumulation. We further demonstrated that the normal assumption of complete protein renewal and the standard practice of taking a single sample with isotope labeling have profound impacts on interpretation of the genesis of fibrosis. Strategies to maintain muscle function with aging should focus on the dynamic protein pool with attention to methodological strategies to assess those changes.
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Affiliation(s)
| | | | - Kamil A Kobak
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Erika Barboza Prado Lopes
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Frederick F Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Elizabeth J Donald
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Holly Van Remmen
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Timothy M Griffin
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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7
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Lu G, Wu Z, Shang J, Xie Z, Chen C, Zhang C. The effects of metformin on autophagy. Biomed Pharmacother 2021; 137:111286. [PMID: 33524789 DOI: 10.1016/j.biopha.2021.111286] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/11/2022] Open
Abstract
Metformin is the first-line option for treating newly diagnosed diabetic patients and also involved in other pharmacological actions, including antitumor effect, anti-aging effect, polycystic ovarian syndrome prevention, cardiovascular action, and neuroprotective effect, etc. However, the mechanisms of metformin actions were not fully illuminated. Recently, increasing researches showed that autophagy is a vital medium of metformin playing pharmacological actions. Nevertheless, results on the effects of metformin on autophagy were inconsistent. Apart from few clinical evidences, more data focused on kinds of no-clinical models. First, many studies showed that metformin could induce autophagy via a number of signaling pathways, including AMPK-related signaling pathways (e.g. AMPK/mTOR, AMPK/CEBPD, MiTF/TFE, AMPK/ULK1, and AMPK/miR-221), Redd1/mTOR, STAT, SIRT, Na+/H+ exchangers, MAPK/ERK, PK2/PKR/AKT/ GSK3β, and TRIB3. Secondly, some signaling pathways were involved in the process of metformin inhibiting autophagy, such as AMPK-related signaling pathways (AMPK/NF-κB and other undetermined AMPK-related signaling pathways), Hedgehog, miR-570-3p, miR-142-3p, and MiR-3127-5p. Thirdly, two types of signaling pathways including PI3K/AKT/mTOR and endoplasmic reticulum (ER) stress could bidirectionally impact the effectiveness of metformin on autophagy. Finally, multiple signal pathways were reviewed collectively in terms of affecting the effectiveness of metformin on autophagy. The pharmacological effects of metformin combining its actions on autophagy were also discussed. It would help better apply metformin to treat diseases in term of mediating autophagy.
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Affiliation(s)
- Guangli Lu
- School of Business, Henan University, Henan, Kaifeng, China
| | - Zhen Wu
- Institute of Nursing and Health, College of Nursing and Health, Henan University, Henan, Kaifeng, China
| | - Jia Shang
- School of Kaifeng Culture and Tourism, Henan, Kaifeng, China
| | - Zhenxing Xie
- School of Basic Medicine, Henan University, Henan, Kaifeng, Jinming Avenue, 475004, China.
| | - Chaoran Chen
- Institute of Nursing and Health, College of Nursing and Health, Henan University, Henan, Kaifeng, China.
| | - Chuning Zhang
- Institute of Nursing and Health, College of Nursing and Health, Henan University, Henan, Kaifeng, China
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8
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Lamming DW, Salmon AB. TORwards a Victory Over Aging. J Gerontol A Biol Sci Med Sci 2020; 75:1-3. [PMID: 31544928 DOI: 10.1093/gerona/glz212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Indexed: 01/12/2023] Open
Affiliation(s)
- Dudley W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin.,Department of Medicine, University of Wisconsin-Madison, San Antonio
| | - Adam B Salmon
- Geriatric Research, Education and Clinical Center, South Texas Veterans Healthcare System, San Antonio.,The Sam and Ann Barshop Institute for Longevity and Aging Studies, Department of Molecular Medicine, UT Health San Antonio, Texas
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9
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Malin SK, Stewart NR. Metformin May Contribute to Inter-individual Variability for Glycemic Responses to Exercise. Front Endocrinol (Lausanne) 2020; 11:519. [PMID: 32849302 PMCID: PMC7431621 DOI: 10.3389/fendo.2020.00519] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/26/2020] [Indexed: 12/20/2022] Open
Abstract
Metformin and exercise independently improve glycemic control. Metformin traditionally is considered to reduce hepatic glucose production, while exercise training is thought to stimulate skeletal muscle glucose disposal. Collectively, combining treatments would lead to the anticipation for additive glucose regulatory effects. Herein, we discuss recent literature suggesting that metformin may inhibit, enhance or have no effect on exercise mediated benefits toward glucose regulation, with particular emphasis on insulin sensitivity. Importantly, we address issues surrounding the impact of metformin on exercise induced glycemic benefit across multiple insulin sensitive tissues (e.g., skeletal muscle, liver, adipose, vasculature, and the brain) in effort to illuminate potential sources of inter-individual glycemic variation. Therefore, the review identifies gaps in knowledge that require attention in order to optimize medical approaches that improve care of people with elevated blood glucose levels and are at risk of cardiovascular disease.
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Affiliation(s)
- Steven K. Malin
- Department of Kinesiology, University of Virginia, Charlottesville, VA, United States
- Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, United States
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, United States
| | - Nathan R. Stewart
- Department of Kinesiology, University of Virginia, Charlottesville, VA, United States
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Wolff CA, Lawrence MM, Porter H, Zhang Q, Reid JJ, Laurin JL, Musci RV, Linden MA, Peelor FF, Wren JD, Creery JS, Cutler KJ, Carson RH, Price JC, Hamilton KL, Miller BF. Sex differences in changes of protein synthesis with rapamycin treatment are minimized when metformin is added to rapamycin. GeroScience 2020; 43:809-828. [PMID: 32761290 PMCID: PMC8110668 DOI: 10.1007/s11357-020-00243-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/29/2020] [Indexed: 12/18/2022] Open
Abstract
Loss of protein homeostasis is a hallmark of the aging process. We and others have previously shown that maintenance of proteostasis is a shared characteristic of slowed-aging models. Rapamycin (Rap) exerts sex-specific effects on murine lifespan, but the combination of Rap with the anti-hyperglycemic drug metformin (Rap + Met) equally increases male and female mouse median lifespan. In the current investigation, we compare the effects of short-term (8 weeks) Rap and Rap + Met treatments on bulk and individual protein synthesis in two key metabolic organs (the liver and skeletal muscle) of young genetically heterogeneous mice using deuterium oxide. We report for the first time distinct effects of Rap and Rap + Met treatments on bulk and individual protein synthesis in young mice. Although there were decreases in protein synthesis as assessed by bulk measurements, individual protein synthesis analyses demonstrate there were nearly as many proteins that increased synthesis as decreased synthesis rates. While we observed the established sex- and tissue-specific effects of Rap on protein synthesis, adding Met yielded more uniform effects between tissue and sex. These data offer mechanistic insight as to how Rap + Met may extend lifespan in both sexes while Rap does not.
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Affiliation(s)
- Christopher A Wolff
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, 32610, USA
| | - Marcus M Lawrence
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA.
| | - Hunter Porter
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Qian Zhang
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Justin J Reid
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Jaime L Laurin
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Robert V Musci
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Melissa A Linden
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Pennington Biomedical Research Foundation, Baton Rouge, LA, 70808, USA
| | - Frederick F Peelor
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Jonathan D Wren
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Joseph S Creery
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA
| | - Kyle J Cutler
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA
| | - Richard H Carson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA
| | - John C Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
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11
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Miller BF, Reid JJ, Price JC, Lin HJL, Atherton PJ, Smith K. CORP: The use of deuterated water for the measurement of protein synthesis. J Appl Physiol (1985) 2020; 128:1163-1176. [PMID: 32213116 DOI: 10.1152/japplphysiol.00855.2019] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The use of deuterium oxide (D2O) has greatly expanded the scope of what is possible for the measurement of protein synthesis. The greatest asset of D2O labeling is that it facilitates the measurement of synthesis rates over prolonged periods of time from single proteins through integrated tissue-based measurements. Because the ease of administration, the method is amenable for use in a variety of models and conditions. Although the method adheres to the same rules as other isotope methods, the flexibility can create conditions that are not the same as other approaches and thus requires careful execution to maintain validity and reliability. For this CORP article, we provide a history that gave rise to the method and discuss the advantages and disadvantages of the method, the critical assumptions, guidelines, and best practices based on instrumentation, models, and experimental design. The goal of this CORP article is to propagate additional use of D2O in a manner that produces reliable and valid data.
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Affiliation(s)
- Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Justin J Reid
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - John C Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah
| | - Hsien-Jung L Lin
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah
| | - Philip J Atherton
- MRC-ARUK Center for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - Kenneth Smith
- MRC-ARUK Center for Musculoskeletal Ageing Research, School of Medicine, University of Nottingham, Derby, United Kingdom
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12
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Musci RV, Hamilton KL, Linden MA. Exercise-Induced Mitohormesis for the Maintenance of Skeletal Muscle and Healthspan Extension. Sports (Basel) 2019; 7:E170. [PMID: 31336753 PMCID: PMC6681340 DOI: 10.3390/sports7070170] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/07/2019] [Accepted: 07/09/2019] [Indexed: 12/25/2022] Open
Abstract
Oxidative damage is one mechanism linking aging with chronic diseases including the progressive loss of skeletal muscle mass and function called sarcopenia. Thus, mitigating oxidative damage is a potential avenue to prevent or delay the onset of chronic disease and/or extend healthspan. Mitochondrial hormesis (mitohormesis) occurs when acute exposure to stress stimulates adaptive mitochondrial responses that improve mitochondrial function and resistance to stress. For example, an acute oxidative stress via mitochondrial superoxide production stimulates the activation of endogenous antioxidant gene transcription regulated by the redox sensitive transcription factor Nrf2, resulting in an adaptive hormetic response. In addition, acute stresses such as aerobic exercise stimulate the expansion of skeletal muscle mitochondria (i.e., mitochondrial biogenesis), constituting a mitohormetic response that protects from sarcopenia through a variety of mechanisms. This review summarized the effects of age-related declines in mitochondrial and redox homeostasis on skeletal muscle protein homeostasis and highlights the mitohormetic mechanisms by which aerobic exercise mitigates these age-related declines and maintains function. We discussed the potential efficacy of targeting the Nrf2 signaling pathway, which partially mediates adaptation to aerobic exercise, to restore mitochondrial and skeletal muscle function. Finally, we highlight knowledge gaps related to improving redox signaling and make recommendations for future research.
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Affiliation(s)
- Robert V Musci
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA.
| | - Karyn L Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
| | - Melissa A Linden
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
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