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Hesketh SJ. Advancing cancer cachexia diagnosis with -omics technology and exercise as molecular medicine. SPORTS MEDICINE AND HEALTH SCIENCE 2024; 6:1-15. [PMID: 38463663 PMCID: PMC10918365 DOI: 10.1016/j.smhs.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 03/12/2024] Open
Abstract
Muscle atrophy exacerbates disease outcomes and increases mortality, whereas the preservation of skeletal muscle mass and function play pivotal roles in ensuring long-term health and overall quality-of-life. Muscle atrophy represents a significant clinical challenge, involving the continued loss of muscle mass and strength, which frequently accompany the development of numerous types of cancer. Cancer cachexia is a highly prevalent multifactorial syndrome, and although cachexia is one of the main causes of cancer-related deaths, there are still no approved management strategies for the disease. The etiology of this condition is based on the upregulation of systemic inflammation factors and catabolic stimuli, resulting in the inhibition of protein synthesis and enhancement of protein degradation. Numerous necessary cellular processes are disrupted by cachectic pathology, which mediate intracellular signalling pathways resulting in the net loss of muscle and organelles. However, the exact underpinning molecular mechanisms of how these changes are orchestrated are incompletely understood. Much work is still required, but structured exercise has the capacity to counteract numerous detrimental effects linked to cancer cachexia. Primarily through the stimulation of muscle protein synthesis, enhancement of mitochondrial function, and the release of myokines. As a result, muscle mass and strength increase, leading to improved mobility, and quality-of-life. This review summarises existing knowledge of the complex molecular networks that regulate cancer cachexia and exercise, highlighting the molecular interplay between the two for potential therapeutic intervention. Finally, the utility of mass spectrometry-based proteomics is considered as a way of establishing early diagnostic biomarkers of cachectic patients.
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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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Agergaard J, Justesen TEH, Jespersen SE, Tagmose Thomsen T, Holm L, van Hall G. Even or skewed dietary protein distribution is reflected in the whole-body protein net-balance in healthy older adults: A randomized controlled trial. Clin Nutr 2023; 42:899-908. [PMID: 37086618 DOI: 10.1016/j.clnu.2023.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/21/2023] [Accepted: 04/05/2023] [Indexed: 04/24/2023]
Abstract
BACKGROUND & AIM For older adults, the dietary protein intake has shown to be skewed towards the evening meal. Resultingly, the vital source of essential amino acids could be insufficient after some meals, while after the evening meal the dietary protein could be suboptimally utilized for protein synthesis. The present study explored if an even distribution of the protein intake could improve the dietary amino acid absorption and whole-body protein net-balance. METHODS Twenty-four healthy elderly males and females were included in a randomized controlled trial. Ten days of habituation to either an EVEN (n = 12) or SKEWED (n = 12) protein intake, was followed by a trial day. The total protein intake was controlled at 1.5 g/kg LBM, divided into 30% at each main meal in EVEN, and into 15% at breakfast and lunch and 60% at dinner in SKEWED. Snacks with 5% of the protein intake were served between meals. Energy intake in the meals and snacks were equal in both groups. Intrinsically labelled 2H5-phenylalanine minced meat was served as the dietary protein to assess the amino acid absorption. On the trial day, infusion of 2H8-phenylalanine and 2H2-tyrosine, and blood samples taken over 11 h were used to measure whole-body protein turnover. Vastus lateralis muscle biopsies were taken to measure 9 h muscle protein FSR. RESULTS Amino acid absorption rates and concentrations were greater in EVEN compared to SKEWED protein intake. Whole-body protein breakdown rates were lower with similar protein synthesis rates, and consequently the net-balance was greater in EVEN after breakfast and lunch compared to SKEWED and were the same in both groups after dinner. Muscle protein FSR were not different between EVEN and SKEWED. CONCLUSIONS The whole-body protein net-balance was more positive in EVEN compared to SKEWED for an extended time of the measured period, driven by a lower whole-body protein breakdown in EVEN. CLINICAL TRIALS REGISTRATION NCT03870425, https://clinicaltrials.gov/ct2/show/NCT03870425.
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Affiliation(s)
- Jakob Agergaard
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark; Center for Healthy Ageing, Department of Clinical Medicine, University of Copenhagen, Denmark.
| | - Thomas Ehlig Hjermind Justesen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark; Center for Healthy Ageing, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Simon Elmer Jespersen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark; Center for Healthy Ageing, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Thomas Tagmose Thomsen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark; Center for Healthy Ageing, Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Lars Holm
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, United Kingdom
| | - Gerrit van Hall
- Clinical Metabolomics Core Facility, Clinical Biochemistry, Rigshospitalet & Department of Biomedical Sciences, Faculty of Health & Medical Science, University of Copenhagen, Denmark
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Sadri H, Ghaffari MH, Sauerwein H. Invited review: Muscle protein breakdown and its assessment in periparturient dairy cows. J Dairy Sci 2023; 106:822-842. [PMID: 36460512 DOI: 10.3168/jds.2022-22068] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022]
Abstract
Mobilization of body reserves including fat, protein, and glycogen is necessary to overcome phases of negative nutrient balance typical for high-yielding dairy cows during the periparturient period. Skeletal muscle, the largest internal organ in mammals, plays a crucial role in maintaining metabolic homeostasis. However, unlike in liver and adipose tissue, the metabolic and regulatory role of skeletal muscle in the adaptation of dairy cows to the physiological needs of pregnancy and lactation has not been studied extensively. The functional integrity and quality of skeletal muscle are maintained through a constant turnover of protein, resulting from both protein breakdown and protein synthesis. Thus, muscle protein breakdown (MPB) and synthesis are intimately connected and tightly controlled to ensure proper protein homeostasis. Understanding the regulation of MPB, the catabolic component of muscle turnover, and its assessment are therefore important considerations to provide information about the timing and extent of tissue mobilization in periparturient dairy cows. Based on animal models and human studies, it is now evident that MPB occurs via the integration of 3 main systems: autophagy-lysosomal, calpain Ca2+-dependent cysteine proteases, and the ubiquitin-proteasome system. These 3 main systems are interconnected and do not work separately, and the regulation is complex. The ubiquitin-proteasomal system is the most well-known cellular proteolytic system and plays a fundamental role in muscle physiology. Complete degradation of a protein often requires a combination of the systems, depending on the physiological situation. Determination of MPB in dairy cows is technically challenging, resulting in a relative dearth of information. The methods for assessing MPB can be divided into either direct or indirect measurements, both having their strengths and limitations. Available information on the direct measures of MPB primarily comes from stable isotopic tracer methods and those of indirect measurements from assessing expression and activity measures of the components of the 3 MPB systems in muscle biopsy samples. Other indirect approaches (i.e., potential indicators of MPB), including ultrasound imaging and measuring metabolites from muscle degradation (i.e., 3-methylhistidine and creatinine), seem to be applicable methods and can provide useful information about the extent and timing of MPB. This review presents our current understanding, including methodological considerations, of the process of MPB in periparturient dairy cows.
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Affiliation(s)
- H Sadri
- Department of Clinical Science, Faculty of Veterinary Medicine, University of Tabriz, 5166616471 Tabriz, Iran; Institute of Animal Science, Physiology Unit, University of Bonn, 53111 Bonn, Germany.
| | - M H Ghaffari
- Institute of Animal Science, Physiology Unit, University of Bonn, 53111 Bonn, Germany
| | - H Sauerwein
- Institute of Animal Science, Physiology Unit, University of Bonn, 53111 Bonn, Germany
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Comparing Even with Skewed Dietary Protein Distribution Shows No Difference in Muscle Protein Synthesis or Amino Acid Utilization in Healthy Older Individuals: A Randomized Controlled Trial. Nutrients 2022; 14:nu14214442. [PMID: 36364705 PMCID: PMC9654411 DOI: 10.3390/nu14214442] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/22/2022] Open
Abstract
Sarcopenia is a multifactorial disease that limits autonomy for the growing elderly population. An optimal amount of dietary protein has shown to be important to maintain muscle mass during aging. Yet, the optimal distribution of that dietary protein has not been fully clarified. The aim of the present study was to examine whether an even, compared to a skewed, distribution of daily dietary protein leads to higher muscle protein synthesis and amino acid utilization. Twelve healthy males and twelve healthy females aged between 65 and 80 years were block randomized to either an even (EVEN, n = 12) or skewed (SKEWED, n = 12) dietary protein distribution for three daily main meals. Seven days of habituation were followed by three trial days, which were initiated by oral intake of deuterium oxide (D2O). The dietary protein throughout all trial meals was intrinsically labelled with 2H5-phenylalanine. Blood samples were drawn daily, and muscle biopsies were taken before and at the end of the trial to measure muscle protein synthesis (FSR) and muscle protein incorporation of the dietary-protein-derived tracer. Muscle protein FSR was no different between the two groups (EVEN 2.16 ± 0.13%/day and SKEWED 2.23 ± 0.09%/day, p = 0.647), and the muscle protein incorporation of the intrinsically labeled 2H5-phenylalanine tracer was not different between the two groups (EVEN 0.0049 ± 0.0004 MPE% and SKEWED 0.0054 ± 0.0003 MPE%, p = 0.306). In conclusion, the daily distribution pattern of the dietary protein did not affect muscle protein synthesis or the utilization of dietary protein.
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Brook MS, Stokes T, Gorissen SH, Bass JJ, McGlory C, Cegielski J, Wilkinson DJ, Phillips BE, Smith K, Phillips SM, Atherton PJ. Declines in muscle protein synthesis account for short-term muscle disuse atrophy in humans in the absence of increased muscle protein breakdown. J Cachexia Sarcopenia Muscle 2022; 13:2005-2016. [PMID: 35606155 PMCID: PMC9397550 DOI: 10.1002/jcsm.13005] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND We determined the short-term (i.e. 4 days) impacts of disuse atrophy in relation to muscle protein turnover [acute fasted-fed muscle protein synthesis (MPS)/muscle protein breakdown (MPB) and integrated MPS/estimated MPB]. METHODS Healthy men (N = 9, 22 ± 2 years, body mass index 24 ± 3 kg m-2 ) underwent 4 day unilateral leg immobilization. Vastus lateralis (VL) muscle thickness (MT) and extensor strength and thigh lean mass (TLM) were measured. Bilateral VL muscle biopsies were collected on Day 4 at t = -120, 0, 90, and 180 min to determine integrated MPS, estimated MPB, acute fasted-fed MPS (l-[ring-13 C6 ]-phe), and acute fasted tracer decay rate representative of MPB (l-[15 N]-phe and l-[2 H8 ]-phe). Protein turnover cell signalling was measured by immunoblotting. RESULTS Immobilization decreased TLM [pre: 7477 ± 1196 g, post: 7352 ± 1209 g (P < 0.01)], MT [pre: 2.67 ± 0.50 cm, post: 2.55 ± 0.51 cm (P < 0.05)], and strength [pre: 260 ± 43 N m, post: 229 ± 37 N m (P < 0.05)] with no change in control legs. Integrated MPS decreased in immob vs. control legs [control: 1.55 ± 0.21% day-1 , immob: 1.29 ± 0.17% day-1 (P < 0.01)], while tracer decay rate (i.e. MPB) (control: 0.02 ± 0.006, immob: 0.015 ± 0.015) and fractional breakdown rate (FBR) remained unchanged [control: 1.44 ± 0.51% day-1 , immob: 1.73 ± 0.35% day-1 (P = 0.21)]. Changes in MT correlated with those in MPS but not FBR. MPS increased in the control leg following feeding [fasted: 0.043 ± 0.012% h-1 , fed: 0.065 ± 0.017% h-1 (P < 0.05)] but not in immob [fasted: 0.034 ± 0.014% h-1 , fed: 0.049 ± 0.023% h-1 (P = 0.09)]. There were no changes in markers of MPB with immob (P > 0.05). CONCLUSIONS Human skeletal muscle disuse atrophy is driven by declines in MPS, not increases in MPB. Pro-anabolic therapies to mitigate disuse atrophy would likely be more effective than therapies aimed at attenuating protein degradation.
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Affiliation(s)
- Matthew S. Brook
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
- School of Life SciencesUniversity of NottinghamNottinghamUK
| | - Tanner Stokes
- Department of KinesiologyMcMaster UniversityHamiltonONCanada
| | | | - Joseph J. Bass
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
| | - Chris McGlory
- School of Kinesiology and Health StudiesQueen's UniversityKingstonONCanada
| | - Jessica Cegielski
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
| | - Daniel J. Wilkinson
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
| | - Bethan E. Phillips
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
| | - Ken Smith
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
| | | | - Philip J. Atherton
- MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre Of Metabolism, Ageing and Physiology (COMAP), School of MedicineUniversity of NottinghamDerbyUK
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The regional turnover of cartilage collagen matrix in late-stage human knee osteoarthritis. Osteoarthritis Cartilage 2022; 30:886-895. [PMID: 35358700 DOI: 10.1016/j.joca.2022.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/03/2022] [Accepted: 03/22/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Cartilage collagen has very limited repair potential, though some turnover and incorporation has not been fully excluded. We aim to determine the regional turnover of human osteoarthritis cartilage. DESIGN Patients scheduled for knee joint replacement surgery due to osteoarthritis were recruited in this prospective study of four weeks duration. Deuterium oxide (D2O) was administered orally by weekly boluses at 70% D2O, initially 150 ml followed by three boluses of 50 ml. Cartilage from the medial tibia plateau was sampled centrally, under the meniscus, and from osteophytes and treated enzymatically with hyaluronidase and trypsin. Samples were analysed for deuterium incorporation in alanine using mass spectrometry and for gene expression by real-time reverse transcriptase polymerase chain reaction. RESULTS Twenty participants completed the study: mean (SD) age 64 ± 9.1 years, 45% female, BMI 29.5 ± 4.8 kg/m2. Enzymatically treated cartilage from central and submeniscal regions showed similar enrichments at 0.063% APE, while osteophytes showed significantly greater enrichment at 0.072% APE (95% confidence interval of difference) [0.004-0.015]). Fractional synthesis rates were similar for central 0.027%/day and submeniscal cartilage 0.022%/day but 10-fold higher in osteophytes 0.22%/day [0.098-0.363]. When compared to central cartilage, submeniscal cartilage had increased gene expression of MMP-3 and decreased lubricin expression. Untreated cartilage had higher turnover (enrichments at 0.073% APE) than enzymatically treated cartilage (0.063% APE). CONCLUSIONS In OA, despite regional differences in gene expression, the turnover of the articular cartilage matrix across the entire joint surface is very limited, but higher turnover was observed in osteophyte cartilage.
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Jaconelli M, Greenhaff PL, Atherton PJ, Lobo DN, Brook MS. The effects of elective abdominal surgery on protein turnover: A meta-analysis of stable isotope techniques to investigate postoperative catabolism. Clin Nutr 2022; 41:709-722. [PMID: 35168004 PMCID: PMC8902515 DOI: 10.1016/j.clnu.2022.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND & AIMS Elective surgery induces skeletal muscle wasting driven by an imbalance between muscle protein synthesis and breakdown. From examination of diverse stable isotope tracer techniques, the dynamic processes driving this imbalance are unclear. This meta-analysis aimed to elucidate the mechanistic driver(s) of postoperative protein catabolism through stable isotope assessment of protein turnover before and after abdominal surgery. METHODS Meta-analysis was performed of randomized controlled trials and cohort studies in patients undergoing elective abdominal surgery that contained measurements of whole-body or skeletal muscle protein turnover using stable isotope tracer methodologies pre- and postoperatively. Postoperative changes in protein synthesis and breakdown were assessed through subgroup analysis of tracer methodology and perioperative care. RESULTS Surgery elicited no overall change in protein synthesis [standardized mean difference (SMD) -0.47, 95% confidence interval (CI): -1.32, 0.39, p = 0.25]. However, subgroup analysis revealed significant suppressions via direct-incorporation methodology [SMD -1.53, 95%CI: -2.89, -0.17, p = 0.03] within skeletal muscle. Changes of this nature were not present among arterio-venous [SMD 0.61, 95%CI: -1.48, 2.70, p = 0.58] or end-product [SMD -0.09, 95%CI: -0.81, 0.64, p = 0.82] whole-body measures. Surgery resulted in no overall change in protein breakdown [SMD 0.63, 95%CI: -0.06, 1.32, p = 0.07]. Yet, separation by tracer methodology illustrated significant increases in urinary end-products (urea/ammonia) [SMD 0.70, 95%CI: 0.38, 1.02, p < 0.001] that were not present among arterio-venous measures [SMD 0.67, 95%CI: -1.05, 2.38, p = 0.45]. CONCLUSIONS Elective abdominal surgery elicits suppressions in skeletal muscle protein synthesis that are not reflected on a whole-body level. Lack of uniform changes across whole-body tracer techniques are likely due to contribution from tissues other than skeletal muscle.
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Affiliation(s)
- Matthew Jaconelli
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Paul L Greenhaff
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK; National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals and University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Philip J Atherton
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals and University of Nottingham, Queen's Medical Centre, Nottingham, UK; School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Dileep N Lobo
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals and University of Nottingham, Queen's Medical Centre, Nottingham, UK; Gastrointestinal Surgery, Nottingham Digestive Diseases Centre, Nottingham University Hospitals and University of Nottingham, Queen's Medical Centre, Nottingham, UK.
| | - Matthew S Brook
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK; National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals and University of Nottingham, Queen's Medical Centre, Nottingham, UK
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Reitelseder S, Bülow J, Holm L. Divergent Anabolic Response to Exercise in Young and Older Adult Men-Dependency on Time Frame of Measurement. J Gerontol A Biol Sci Med Sci 2021; 76:996-999. [PMID: 33539523 PMCID: PMC8266534 DOI: 10.1093/gerona/glab040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Indexed: 01/08/2023] Open
Abstract
Older adults’ skeletal muscle has shown to be less responsive to anabolic stimuli as compared to young both in vitro, in short and controlled in vivo settings and in long-term training studies. However, to translate controlled mechanistic findings to long-term adaptations intermediate measures allowing daily life routines with regard to activity and diet would be useful to evaluate physiological interventions. The purpose of this study was to investigate the exercise effect in young and older adults with 2 independent methods to measure muscle protein synthesis rate. Healthy young and old men were recruited to the study protocol where myofibrillar fractional synthesis rate was measured during 2 days allowing normal activities of daily living with D2O-labeled alanine and during 4 hours in the overnight fasted state with [13C6]phenylalanine infusion. During this period 1 leg completed an exercise session every day (exercise leg) while the contralateral leg was kept inactive (normal leg). Both legs were used for activities of daily living. Two-day myofibrillar fractional synthesis rate was significantly higher in the exercise leg in both young and old as compared to normal leg with no age difference. The 4-hour overnight fasted myofibrillar fractional synthesis rate showed that only young exercise leg was significantly higher than normal leg. The present findings support the notion that anabolic resistance exists in the skeletal muscle of healthy older men when evaluated in controlled settings. However, this response is not as clear when measured during daily life where variance is greater, which calls for further investigations in larger cohorts.
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Affiliation(s)
- Søren Reitelseder
- Department of Orthopedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jacob Bülow
- Department of Orthopedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Denmark
| | - Lars Holm
- Department of Orthopedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Denmark.,School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, UK
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Nishimura Y, Musa I, Holm L, Lai YC. Recent advances in measuring and understanding the regulation of exercise-mediated protein degradation in skeletal muscle. Am J Physiol Cell Physiol 2021; 321:C276-C287. [PMID: 34038244 DOI: 10.1152/ajpcell.00115.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Skeletal muscle protein turnover plays a crucial role in controlling muscle mass and protein quality control, including sarcomeric (structural and contractile) proteins. Protein turnover is a dynamic and continual process of protein synthesis and degradation. The ubiquitin proteasome system (UPS) is a key degradative system for protein degradation and protein quality control in skeletal muscle. UPS-mediated protein quality control is known to be impaired in aging and diseases. Exercise is a well-recognized, nonpharmacological approach to promote muscle protein turnover rates. Over the past decades, we have acquired substantial knowledge of molecular mechanisms of muscle protein synthesis after exercise. However, there have been considerable gaps in the mechanisms of how muscle protein degradation is regulated at the molecular level. The main challenge to understand muscle protein degradation is due in part to the lack of solid stable isotope tracer methodology to measure muscle protein degradation rate. Understanding the mechanisms of UPS with the concomitant measurement of protein degradation rate in skeletal muscle will help identify novel therapeutic strategies to ameliorate impaired protein turnover and protein quality control in aging and diseases. Thus, the goal of this present review was to highlight how recent advances in the field may help improve our understanding of exercise-mediated protein degradation. We discuss 1) the emerging roles of protein phosphorylation and ubiquitylation modifications in regulating proteasome-mediated protein degradation after exercise and 2) methodological advances to measure in vivo myofibrillar protein degradation rate using stable isotope tracer methods.
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Affiliation(s)
- Yusuke Nishimura
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ibrahim Musa
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Lars Holm
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom
| | - Yu-Chiang Lai
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
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11
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McKendry J, Stokes T, Mcleod JC, Phillips SM. Resistance Exercise, Aging, Disuse, and Muscle Protein Metabolism. Compr Physiol 2021; 11:2249-2278. [PMID: 34190341 DOI: 10.1002/cphy.c200029] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Skeletal muscle is the organ of locomotion, its optimal function is critical for athletic performance, and is also important for health due to its contribution to resting metabolic rate and as a site for glucose uptake and storage. Numerous endogenous and exogenous factors influence muscle mass. Much of what is currently known regarding muscle protein turnover is owed to the development and use of stable isotope tracers. Skeletal muscle mass is determined by the meal- and contraction-induced alterations of muscle protein synthesis and muscle protein breakdown. Increased loading as resistance training is the most potent nonpharmacological strategy by which skeletal muscle mass can be increased. Conversely, aging (sarcopenia) and muscle disuse lead to the development of anabolic resistance and contribute to the loss of skeletal muscle mass. Nascent omics-based technologies have significantly improved our understanding surrounding the regulation of skeletal muscle mass at the gene, transcript, and protein levels. Despite significant advances surrounding the mechanistic intricacies that underpin changes in skeletal muscle mass, these processes are complex, and more work is certainly needed. In this article, we provide an overview of the importance of skeletal muscle, describe the influence that resistance training, aging, and disuse exert on muscle protein turnover and the molecular regulatory processes that contribute to changes in muscle protein abundance. © 2021 American Physiological Society. Compr Physiol 11:2249-2278, 2021.
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Affiliation(s)
- James McKendry
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Tanner Stokes
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Jonathan C Mcleod
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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12
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Understanding the effects of nutrition and post-exercise nutrition on skeletal muscle protein turnover: Insights from stable isotope studies. CLINICAL NUTRITION OPEN SCIENCE 2021. [DOI: 10.1016/j.nutos.2021.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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13
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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: 38] [Impact Index Per Article: 9.5] [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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Muscle protein breakdown is impaired during immobilization compared to during a subsequent retraining period in older men: no effect of anti-inflammatory medication. Pflugers Arch 2020; 472:281-292. [PMID: 32025814 PMCID: PMC7035225 DOI: 10.1007/s00424-020-02353-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/29/2019] [Accepted: 01/26/2020] [Indexed: 12/25/2022]
Abstract
Muscle inactivity reduces muscle protein synthesis (MPS), whereas a subsequent period of rehabilitation resistance training (retraining) increases MPS. However, less is known regarding muscle protein breakdown (MPB) during such conditions. Furthermore, nonsteroidal anti-inflammatory drugs (NSAIDs) may have a dampening effect on MPB during periods of inactivity in older individuals. Thus, we measured the average MPB, by use of the deuterated water methodology, during an immobilization period and a subsequent retraining period in older individuals with and without NSAID treatment. Eighteen men (60–80 years: range) were randomly assigned to ibuprofen (1200 mg/d, Ibu) or placebo (Plc). One lower limb was immobilized in a cast for 2 weeks and retrained for 2 weeks, and 2 × 20 g of whey protein was ingested daily during both periods. Besides MPB, the protein expression of different muscle degradation signaling molecules was investigated. MPB was lower during immobilization compared to retraining (p < 0.01). NSAID treatment did not affect the MPB rate during immobilization or retraining (p > 0.05). The protein expression of muscle degradation signaling molecules changed during the study intervention but were unaffected by NSAID treatment. The finding that MPB was lower during immobilization than during retraining indicates that an increased MPB may play an important role in the muscle protein remodeling processes taking place within the initial retraining period. Moreover, NSAID treatment did not significantly influence the MPB rate during 2 weeks of lower limb immobilization or during 2 weeks of subsequent retraining in older individuals.
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Holm L, Dideriksen K, Nielsen RH, Doessing S, Bechshoeft RL, Højfeldt G, Moberg M, Blomstrand E, Reitelseder S, van Hall G. An exploration of the methods to determine the protein-specific synthesis and breakdown rates in vivo in humans. Physiol Rep 2019; 7:e14143. [PMID: 31496135 PMCID: PMC6732504 DOI: 10.14814/phy2.14143] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 01/02/2023] Open
Abstract
The present study explores the methods to determine human in vivo protein-specific myofibrillar and collagenous connective tissue protein fractional synthesis and breakdown rates. We found that in human myofibrillar proteins, the protein-bound tracer disappearance method to determine the protein fractional breakdown rate (FBR) (via 2 H2 O ingestion, endogenous labeling of 2 H-alanine that is incorporated into proteins, and FBR quantified by its disappearance from these proteins) has a comparable intrasubject reproducibility (range: 0.09-53.5%) as the established direct-essential amino acid, here L-ring-13 C6 -phenylalanine, incorporation method to determine the muscle protein fractional synthesis rate (FSR) (range: 2.8-56.2%). Further, the determination of the protein breakdown in a protein structure with complex post-translational processing and maturation, exemplified by human tendon tissue, was not achieved in this experimentation, but more investigation is encouraged to reveal the possibility. Finally, we found that muscle protein FBR measured with an essential amino acid tracer prelabeling is inappropriate presumably because of significant and prolonged intracellular recycling, which also may become a significant limitation for determination of the myofibrillar FSR when repeated infusion trials are completed in the same participants.
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Affiliation(s)
- Lars Holm
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- School of Sport, Exercise and Rehabilitation SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Kasper Dideriksen
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
| | - Rie H. Nielsen
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
| | - Simon Doessing
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
| | - Rasmus L. Bechshoeft
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Grith Højfeldt
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
| | - Marcus Moberg
- Aastrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden
| | - Eva Blomstrand
- Aastrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Søren Reitelseder
- Institute of Sports Medicine and Department of Orthopedic Surgery MBispebjerg HospitalCopenhagenDenmark
| | - Gerrit van Hall
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Clinical Metabolomics Core FacilityDepartment of Clinical Biochemistry, RigshospitaletCopenhagenDenmark
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Eldeeb MA, Siva-Piragasam R, Ragheb MA, Esmaili M, Salla M, Fahlman RP. A molecular toolbox for studying protein degradation in mammalian cells. J Neurochem 2019; 151:520-533. [PMID: 31357232 DOI: 10.1111/jnc.14838] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/03/2019] [Accepted: 07/24/2019] [Indexed: 12/14/2022]
Abstract
Protein degradation is a crucial regulatory process in maintaining cellular proteostasis. The selective degradation of intracellular proteins controls diverse cellular and biochemical processes in all kingdoms of life. Targeted protein degradation is implicated in controlling the levels of regulatory proteins as well as eliminating misfolded and any otherwise abnormal proteins. Deregulation of protein degradation is concomitant with the progression of various neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. Thus, methods of measuring metabolic half-lives of proteins greatly influence our understanding of the diverse functions of proteins in mammalian cells including neuronal cells. Historically, protein degradation rates have been studied via exploiting methods that estimate overall protein degradation or focus on few individual proteins. Notably, with the recent technical advances and developments in proteomic and imaging techniques, it is now possible to measure degradation rates of a large repertoire of defined proteins and analyze the degradation profile in a detailed spatio-temporal manner, with the aim of determining proteome-wide protein stabilities upon different physiological conditions. Herein, we discuss some of the classical and novel methods for determining protein degradation rates highlighting the crucial role of some state of art approaches in deciphering the global impact of dynamic nature of targeted degradation of cellular proteins. This article is part of the Special Issue "Proteomics".
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Affiliation(s)
- Mohamed A Eldeeb
- Department of Chemistry (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt.,Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | | | - Mohamed A Ragheb
- Department of Chemistry (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Mansoore Esmaili
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Mohamed Salla
- Department of Biological Sciences, Lebanese International University, Bekaa, Lebanon
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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Abstract
Muscle protein breakdown (MPB) is an important metabolic component of muscle remodeling, adaptation to training, and increasing muscle mass. Degradation of muscle proteins occurs via the integration of three main systems—autophagy and the calpain and ubiquitin-proteasome systems. These systems do not operate independently, and the regulation is complex. Complete degradation of a protein requires some combination of the systems. Determination of MPB in humans is technically challenging, leading to a relative dearth of information. Available information on the dynamic response of MPB primarily comes from stable isotopic methods with expression and activity measures providing complementary information. It seems clear that resistance exercise increases MPB, but not as much as the increase in muscle protein synthesis. Both hyperaminoacidemia and hyperinsulinemia inhibit the post-exercise response of MPB. Available data do not allow a comprehensive examination of the mechanisms behind these responses. Practical nutrition recommendations for interventions to suppress MPB following exercise are often made. However, it is likely that some degree of increased MPB following exercise is an important component for optimal remodeling. At this time, it is not possible to determine the impact of nutrition on any individual muscle protein. Thus, until we can develop and employ better methods to elucidate the role of MPB following exercise and the response to nutrition, recommendations to optimize post exercise nutrition should focus on the response of muscle protein synthesis. The aim of this review is to provide a comprehensive examination of the state of knowledge, including methodological considerations, of the response of MPB to exercise and nutrition in humans.
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The fractional synthesis rates of plasma proteins as determined using deuterated water are sensitive to dietary intake of lysine in rats. Amino Acids 2018; 50:1719-1727. [DOI: 10.1007/s00726-018-2645-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/27/2018] [Indexed: 11/26/2022]
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19
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Wilkinson DJ. Historical and contemporary stable isotope tracer approaches to studying mammalian protein metabolism. MASS SPECTROMETRY REVIEWS 2018; 37:57-80. [PMID: 27182900 PMCID: PMC5763415 DOI: 10.1002/mas.21507] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/22/2016] [Indexed: 06/05/2023]
Abstract
Over a century ago, Frederick Soddy provided the first evidence for the existence of isotopes; elements that occupy the same position in the periodic table are essentially chemically identical but differ in mass due to a different number of neutrons within the atomic nucleus. Allied to the discovery of isotopes was the development of some of the first forms of mass spectrometers, driven forward by the Nobel laureates JJ Thomson and FW Aston, enabling the accurate separation, identification, and quantification of the relative abundance of these isotopes. As a result, within a few years, the number of known isotopes both stable and radioactive had greatly increased and there are now over 300 stable or radioisotopes presently known. Unknown at the time, however, was the potential utility of these isotopes within biological disciplines, it was soon discovered that these stable isotopes, particularly those of carbon (13 C), nitrogen (15 N), oxygen (18 O), and hydrogen (2 H) could be chemically introduced into organic compounds, such as fatty acids, amino acids, and sugars, and used to "trace" the metabolic fate of these compounds within biological systems. From this important breakthrough, the age of the isotope tracer was born. Over the following 80 yrs, stable isotopes would become a vital tool in not only the biological sciences, but also areas as diverse as forensics, geology, and art. This progress has been almost exclusively driven through the development of new and innovative mass spectrometry equipment from IRMS to GC-MS to LC-MS, which has allowed for the accurate quantitation of isotopic abundance within samples of complex matrices. This historical review details the development of stable isotope tracers as metabolic tools, with particular reference to their use in monitoring protein metabolism, highlighting the unique array of tools that are now available for the investigation of protein metabolism in vivo at a whole body down to a single protein level. Importantly, it will detail how this development has been closely aligned to the technological development within the area of mass spectrometry. Without the dedicated development provided by these mass spectrometrists over the past century, the use of stable isotope tracers within the field of protein metabolism would not be as widely applied as it is today, this relationship will no doubt continue to flourish in the future and stable isotope tracers will maintain their importance as a tool within the biological sciences for many years to come. © 2016 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc. Mass Spec Rev.
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Affiliation(s)
- Daniel James Wilkinson
- MRC‐ARUK Centre for Musculoskeletal Ageing Research, Clinical, Metabolic and Molecular PhysiologyUniversity of Nottingham, Royal Derby Hospital CentreDerbyUnited Kingdom
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Oh JH, Chen SJ, Varshavsky A. A reference-based protein degradation assay without global translation inhibitors. J Biol Chem 2017; 292:21457-21465. [PMID: 29122887 DOI: 10.1074/jbc.m117.814236] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/05/2017] [Indexed: 11/06/2022] Open
Abstract
Although it is widely appreciated that the use of global translation inhibitors, such as cycloheximide, in protein degradation assays may result in artefacts, these inhibitors continue to be employed, owing to the absence of robust alternatives. We describe here the promoter reference technique (PRT), an assay for protein degradation with two advantageous features: a reference protein and a gene-specific inhibition of translation. In PRT assays, one measures, during a chase, the ratio of a test protein to a long-lived reference protein, a dihydrofolate reductase (DHFR). The test protein and DHFR are coexpressed, in the yeast Saccharomyces cerevisiae, on a low-copy plasmid from two identical P TDH3 promoters containing additional, previously developed DNA elements. Once transcribed, these elements form 5'-RNA aptamers that bind to the added tetracycline, which represses translation of aptamer-containing mRNAs. The selectivity of repression avoids a global inhibition of translation. This selectivity is particularly important if a component of a relevant proteolytic pathway (e.g. a specific ubiquitin ligase) is itself short-lived. We applied PRT to the Pro/N-end rule pathway, whose substrates include the short-lived Mdh2 malate dehydrogenase. Mdh2 is targeted for degradation by the Gid4 subunit of the GID ubiquitin ligase. Gid4 is also a metabolically unstable protein. Through analyses of short-lived Mdh2 as a target of short-lived Gid4, we illustrate the advantages of PRT over degradation assays that lack a reference and/or involve cycloheximide. In sum, PRT avoids the use of global translation inhibitors during a chase and also provides a "built-in" reference protein.
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Affiliation(s)
- Jang-Hyun Oh
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Shun-Jia Chen
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Alexander Varshavsky
- From the Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
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Bechshøft CL, Schjerling P, Bornø A, Holm L. Existence of life-time stable proteins in mature rats-Dating of proteins' age by repeated short-term exposure to labeled amino acids throughout age. PLoS One 2017; 12:e0185605. [PMID: 28957442 PMCID: PMC5619800 DOI: 10.1371/journal.pone.0185605] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 09/15/2017] [Indexed: 01/08/2023] Open
Abstract
In vivo turnover rates of proteins covering the processes of protein synthesis and breakdown rates have been measured in many tissues and protein pools using various techniques. Connective tissue and collagen protein turnover is of specific interest since existing results are rather diverging. The aim of this study is to investigate whether we can verify the presence of protein pools within the same tissue with very distinct turnover rates over the life-span of rats with special focus on connective tissue. Male and female Lewis rats (n = 35) were injected with five different isotopically labeled amino acids tracers. The tracers were injected during fetal development (Day -10 to -2), after birth (Day 5-9), at weaning (Day 25-32) at puberty (Day 54-58) and at adulthood (Day 447-445). Subgroups of rats were euthanized three days after every injection period, at different time point between injection periods and lastly at day 472. Tissue (liver, muscle, eye lens and patellar tendon) and blood samples were collected after euthanization. The enrichment of the labeled amino acids in the tissue or blood samples was measured using GC-MS-MS. In muscle and liver we demonstrated a rapid decrease of tracer enrichments throughout the rat's life, indicating that myofibrillar and cytoskeleton proteins have a high turnover. In contrast, the connective tissue protein in the eye lens and patellar tendon of the mature rat showed detainment of tracer enrichment injected during fetal development and first living days, indicating very slow turnover. The data support the hypothesis that some proteins synthesized during the early development and growth still exist much later in life of animals and hence has a very slow turnover rate.
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Affiliation(s)
- Cecilie Leidesdorff Bechshøft
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center of Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center of Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Bornø
- Clinical Metabolomics Core Facility, Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Lars Holm
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center of Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Metabolomics Core Facility, Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Institute of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Bila WC, Mariano RMDS, Silva VR, Dos Santos MESM, Lamounier JA, Ferriolli E, Galdino AS. Applications of deuterium oxide in human health. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2017; 53:327-343. [PMID: 28165769 DOI: 10.1080/10256016.2017.1281806] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 10/12/2016] [Indexed: 06/06/2023]
Abstract
The main aim goal of this review was to gather information about recent publications related to deuterium oxide (D2O), and its use as a scientific tool related to human health. Searches were made in electronic databases Pubmed, Scielo, Lilacs, Medline and Cochrane. Moreover, the following patent databases were consulted: EPO (Espacenet patent search), USPTO (United States Patent and Trademark Office) and Google Patents, which cover researches worldwide related to innovations using D2O.
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Affiliation(s)
- Wendell Costa Bila
- a Graduate Programme in Health Sciences , Federal University of São João Del Rei-West Centre Campus , Divinópolis , Brazil
| | - Reysla Maria da Silveira Mariano
- b Graduate Programme in Biochemistry and Molecular Biology , Federal University of São João del Rei , Divinópolis , Brazil
- c Graduate Program in Biotechnology , Federal University of São João del Rei , Divinópolis , Brazil
| | - Valmin Ramos Silva
- d Faculty of Medicine, School of Sciences of Santa Casa de Misericórdia of Vitória , Nossa Senhora da Glória Children's Hospital , Vitória , Brazil
| | | | - Joel Alves Lamounier
- a Graduate Programme in Health Sciences , Federal University of São João Del Rei-West Centre Campus , Divinópolis , Brazil
| | - Eduardo Ferriolli
- e Ribeirão Preto Medical School , University of São Paulo , Ribeirão Preto , Brazil
| | - Alexsandro Sobreira Galdino
- b Graduate Programme in Biochemistry and Molecular Biology , Federal University of São João del Rei , Divinópolis , Brazil
- c Graduate Program in Biotechnology , Federal University of São João del Rei , Divinópolis , Brazil
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Daurio NA, Wang SP, Chen Y, Zhou H, McLaren DG, Roddy TP, Johns DG, Milot D, Kasumov T, Erion MD, Kelley DE, Previs SF. Enhancing Studies of Pharmacodynamic Mechanisms via Measurements of Metabolic Flux: Fundamental Concepts and Guiding Principles for Using Stable Isotope Tracers. J Pharmacol Exp Ther 2017; 363:80-91. [DOI: 10.1124/jpet.117.241091] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 06/14/2017] [Indexed: 11/22/2022] Open
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Anthony TG. Mechanisms of protein balance in skeletal muscle. Domest Anim Endocrinol 2016; 56 Suppl:S23-32. [PMID: 27345321 PMCID: PMC4926040 DOI: 10.1016/j.domaniend.2016.02.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 02/23/2016] [Accepted: 02/29/2016] [Indexed: 01/07/2023]
Abstract
Increased global demand for adequate protein nutrition against a backdrop of climate change and concern for animal agriculture sustainability necessitates new and more efficient approaches to livestock growth and production. Anabolic growth is achieved when rates of new synthesis exceed turnover, producing a positive net protein balance. Conversely, deterioration or atrophy of lean mass is a consequence of a net negative protein balance. During early life and periods of growth, muscle mass is driven by increases in protein synthesis at the level of mRNA translation. Throughout life, muscle mass is further influenced by degradative processes such as autophagy and the ubiquitin proteasome pathway. Multiple signal transduction networks guide and coordinate these processes alongside quality control mechanisms to maintain protein homeostasis (proteostasis). Genetics, hormones, and environmental stimuli each influence proteostasis control, altering capacity and/or efficiency of muscle growth. An overview of recent findings and current methods to assess muscle protein balance and proteostasis is presented. Current efforts to identify novel control points have the potential through selective breeding design or development of hormetic strategies to better promote growth and health span during environmental stress.
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Affiliation(s)
- T G Anthony
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901, USA.
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Bülow J, Agergaard J, Kjaer M, Holm L, Reitelseder S. No additional effect of different types of physical activity on 10-hour muscle protein synthesis in elderly men on a controlled energy- and protein-sufficient diet. Exp Gerontol 2016; 79:16-25. [DOI: 10.1016/j.exger.2016.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/07/2016] [Accepted: 03/11/2016] [Indexed: 12/19/2022]
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Methods of Assessing Human Tendon Metabolism and Tissue Properties in Response to Changes in Mechanical Loading. METABOLIC INFLUENCES ON RISK FOR TENDON DISORDERS 2016; 920:97-106. [DOI: 10.1007/978-3-319-33943-6_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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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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Zhou H, Wang SP, Herath K, Kasumov T, Sadygov RG, Previs SF, Kelley DE. Tracer-based estimates of protein flux in cases of incomplete product renewal: evidence and implications of heterogeneity in collagen turnover. Am J Physiol Endocrinol Metab 2015; 309:E115-21. [PMID: 26015435 PMCID: PMC4596733 DOI: 10.1152/ajpendo.00435.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 05/04/2015] [Indexed: 11/22/2022]
Abstract
The synthesis of various molecules can be estimated by measuring the incorporation of a labeled precursor into a product of interest. Unfortunately, a central problem in many studies has been an inability to estimate the intracellular dilution of the precursor and therein correctly calculate the synthesis of the product; it is generally assumed that measuring the true product labeling is straightforward. We initiated a study to examine liver collagen synthesis and identified an apparent problem with assumptions regarding measurements of the product labeling. Since it is well known that collagen production is relatively slow, we relied on the use of [(2)H]H2O labeling (analogous to a primed infusion) and sampled animals over the course of 16 days. Although the water labeling (the precursor) remained stable and we observed the incorporation of labeled amino acids into collagen, the asymptotic protein labeling was considerably lower than what would be expected based on the precursor labeling. Although this observation is not necessarily surprising (i.e., one might expect that a substantial fraction of the collagen pool would appear "inert" or turn over at a very slow rate), its implications are of interest in certain areas. Herein, we discuss a novel situation in which tracers are used to quantify rates of flux under conditions where a product may not undergo complete replacement. We demonstrate how heterogeneity in the product pool can lead one to the wrong conclusions regarding estimates of flux, and we outline an approach that may help to minimize errors surrounding data interpretation.
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Affiliation(s)
- Haihong Zhou
- Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, New Jersey
| | - Sheng-Ping Wang
- Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, New Jersey
| | - Kithsiri Herath
- Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, New Jersey
| | - Takhar Kasumov
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio; and
| | - Rovshan G Sadygov
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Stephen F Previs
- Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, New Jersey;
| | - David E Kelley
- Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, New Jersey
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Walker DK, Thaden JJ, Deutz NEP. Application of gas chromatography-tandem mass spectrometry (GC/MS/MS) for the analysis of deuterium enrichment of water. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:838-843. [PMID: 26169138 PMCID: PMC4503389 DOI: 10.1002/jms.3593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/04/2015] [Accepted: 03/10/2015] [Indexed: 06/04/2023]
Abstract
Incorporation of deuterium from deuterium oxide ((2) H2 O) into biological components is a commonly used approach in metabolic studies. Determining the dilution of deuterium in the body water (BW) pool can be used to estimate body composition. We describe three sensitive GC/MS/MS methods to measure water enrichment in BW. Samples were reacted with NaOH and U-(13) C3 -acetone in an autosampler vial to promote deuterium exchange with U-(13) C3 -acetone hydrogens. Headspace injections were made of U-(13) C3 -acetone-saturated air onto a 30-m DB-1MS column in electron impact-mode. Subjects ingested 30 ml (2) H2 O, and plasma samples were collected. BW was determined by standard equation. Dual-energy X-ray absorptiometry scans were performed to calculate body mass, body volume and bone mineral content. A four-compartmental model was used to estimate body composition (fat and fat free mass). Full-scan experiments generated an m/z 45 peak and to a lesser extent an m/z 61 peak. Product fragment ions further monitored included 45 and 46 using selected ion monitoring (Method1), the 61 > 45 and 62 > 46 transition using multiple reaction monitoring (MRM; Method2) and the neutral loss, 62 > 45, transition (Method3). MRM methods were optimized for collision energy (CE) and collision-induced dissociation (CID) argon gas pressure with 6 eV CE and 1.5 mTorr CID gas being optimal. Method2 was used for final determination of (2) H2 O enrichment of subjects because of lower natural background. We have developed a sensitive method to determine (2) H2 O enrichment in BW to enable measurement of FM and FFM.
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Affiliation(s)
- Dillon K Walker
- Center for Translational Research in Aging and Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, 77843, USA
| | - John J Thaden
- Center for Translational Research in Aging and Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, 77843, USA
| | - Nicolaas E P Deutz
- Center for Translational Research in Aging and Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, 77843, USA
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30
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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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31
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McGlory C, Phillips SM. Assessing the regulation of skeletal muscle plasticity in response to protein ingestion and resistance exercise: recent developments. Curr Opin Clin Nutr Metab Care 2014; 17:412-7. [PMID: 25105927 DOI: 10.1097/mco.0000000000000083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The main purpose of this review is to discuss novel methodological advances in the assessment of muscle protein synthesis (MPS) in response to protein feeding and resistance exercise. RECENT FINDINGS In the past 20 years, there has been a shift from application of the nitrogen balance methods toward the infusion of stable isotopic tracers to assess rates of MPS in response to a range of perturbations. Although this approach has enabled MPS to be assessed with a greater temporal resolution and precision, the method limits the capture of MPS to relatively short-duration infusions of approximately 3-12 h. Recent refinement of analytical methods to assess long-term MPS responses have now provided a platform for studying the impact of exercise and nutrition on muscle anabolism with an extended temporal resolution from hours to days or even weeks. Finally, novel insights into cellular signaling processes may help delineate the molecular mechanisms that govern skeletal muscle plasticity in response to exercise and feeding. SUMMARY Future work should focus on the impact of novel exercise and nutritional interventions on MPS in an extended postexercise adaptive period, that is, days. The findings of such investigations will help test the long-term efficacy of interventions to enhance skeletal muscle protein reconditioning and hypertrophy.
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Affiliation(s)
- Chris McGlory
- Department of Kinesiology, Exercise Metabolism Research Group, McMaster University, Hamilton, Ontario, USA
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32
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Pasiakos SM, Carbone JW. Assessment of skeletal muscle proteolysis and the regulatory response to nutrition and exercise. IUBMB Life 2014; 66:478-84. [PMID: 25052691 DOI: 10.1002/iub.1291] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/01/2014] [Indexed: 01/07/2023]
Abstract
Skeletal muscle proteolysis is highly regulated, involving complex intramuscular proteolytic systems that recognize and degrade muscle proteins, and recycle free amino acid precursors for protein synthesis and energy production. Autophagy-lysosomal, calpain, and caspase systems are contributors to muscle proteolysis, although the ubiquitin proteasome system (UPS) is the primary mechanism by which actomyosin fragments are degraded in healthy muscle. The UPS is sensitive to mechanical force and nutritional deprivation, as recent reports have demonstrated increased proteolytic gene expression and activity of the UPS in response to resistance and endurance exercise, and short-term negative energy balance. However, consuming dietary protein alone (or free amino acids), or as a primary component of a mixed meal, may attenuate intramuscular protein loss by down-regulating proteolytic gene expression and the catabolic activity of the UPS. Although these studies provide novel insight regarding the intramuscular regulation of skeletal muscle mass, the role of proteolysis in the regulation of skeletal muscle protein turnover in healthy human muscle is not well described. This article provides a contemporary review of the intramuscular regulation of skeletal muscle proteolysis in healthy muscle, methodological approaches to assess proteolysis, and highlights the effects of nutrition and exercise on skeletal muscle proteolysis.
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Affiliation(s)
- Stefan M Pasiakos
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA
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33
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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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