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Rahman FA, Baechler BL, Quadrilatero J. Key considerations for investigating and interpreting autophagy in skeletal muscle. Autophagy 2024:1-12. [PMID: 39007805 DOI: 10.1080/15548627.2024.2373676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024] Open
Abstract
Skeletal muscle plays a crucial role in generating force to facilitate movement. Skeletal muscle is a heterogenous tissue composed of diverse fibers with distinct contractile and metabolic profiles. The intricate classification of skeletal muscle fibers exists on a continuum ranging from type I (slow-twitch, oxidative) to type II (fast-twitch, glycolytic). The heterogenous distribution and characteristics of fibers within and between skeletal muscles profoundly influences cellular signaling; however, this has not been broadly discussed as it relates to macroautophagy/autophagy. The growing interest in skeletal muscle autophagy research underscores the necessity of comprehending the interplay between autophagic responses among skeletal muscles and fibers with different contractile properties, metabolic profiles, and other related signaling processes. We recommend approaching the interpretation of autophagy findings with careful consideration for two key reasons: 1) the distinct behaviors and responses of different skeletal muscles or fibers to various perturbations, and 2) the potential impact of alterations in skeletal muscle fiber type or metabolic profile on observed autophagic outcomes. This review provides an overview of the autophagic profile and response in skeletal muscles/fibers of different types and metabolic profiles. Further, this review discusses autophagic findings in various conditions and diseases that may differentially affect skeletal muscle. Finally, we provide key points of consideration to better enable researchers to fine-tune the design and interpretation of skeletal muscle autophagy experiments.Abbreviation: AKT1: AKT serine/threonine kinase 1; AMPK: AMP-activated protein kinase; ATG: autophagy related; ATG4: autophagy related 4 cysteine peptidase; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; CKD: chronic kidney disease; COPD: chronic obstructive pulmonary disease; CS: citrate synthase; DIA: diaphragm; EDL: extensor digitorum longus; FOXO3/FOXO3A: forkhead box O3; GAS; gastrocnemius; GP: gastrocnemius-plantaris complex; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MYH: myosin heavy chain; PINK1: PTEN induced kinase 1; PLANT: plantaris; PRKN: parkin RBR E3 ubiquitin protein ligase; QUAD: quadriceps; RA: rectus abdominis; RG: red gastrocnemius; RQ: red quadriceps; SOL: soleus; SQSTM1: sequestosome 1; TA: tibialis anterior; WG: white gastrocnemius; WQ: white quadriceps; WVL: white vastus lateralis; VL: vastus lateralis; ULK1: unc-51 like autophagy activating kinase 1.
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Affiliation(s)
- Fasih A Rahman
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Brittany L Baechler
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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Schenk S, Sagendorf TJ, Many GM, Lira AK, de Sousa LGO, Bae D, Cicha M, Kramer KS, Muehlbauer M, Hevener AL, Rector RS, Thyfault JP, Williams JP, Goodyear LJ, Esser KA, Newgard CB, Bodine SC. Physiological Adaptations to Progressive Endurance Exercise Training in Adult and Aged Rats: Insights from the Molecular Transducers of Physical Activity Consortium (MoTrPAC). FUNCTION 2024; 5:zqae014. [PMID: 38984994 PMCID: PMC11245678 DOI: 10.1093/function/zqae014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/31/2024] [Accepted: 03/19/2024] [Indexed: 07/11/2024] Open
Abstract
While regular physical activity is a cornerstone of health, wellness, and vitality, the impact of endurance exercise training on molecular signaling within and across tissues remains to be delineated. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to characterize molecular networks underlying the adaptive response to exercise. Here, we describe the endurance exercise training studies undertaken by the Preclinical Animal Sites Studies component of MoTrPAC, in which we sought to develop and implement a standardized endurance exercise protocol in a large cohort of rats. To this end, Adult (6-mo) and Aged (18-mo) female (n = 151) and male (n = 143) Fischer 344 rats were subjected to progressive treadmill training (5 d/wk, ∼70%-75% VO2max) for 1, 2, 4, or 8 wk; sedentary rats were studied as the control group. A total of 18 solid tissues, as well as blood, plasma, and feces, were collected to establish a publicly accessible biorepository and for extensive omics-based analyses by MoTrPAC. Treadmill training was highly effective, with robust improvements in skeletal muscle citrate synthase activity in as little as 1-2 wk and improvements in maximum run speed and maximal oxygen uptake by 4-8 wk. For body mass and composition, notable age- and sex-dependent responses were observed. This work in mature, treadmill-trained rats represents the most comprehensive and publicly accessible tissue biorepository, to date, and provides an unprecedented resource for studying temporal-, sex-, and age-specific responses to endurance exercise training in a preclinical rat model.
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Affiliation(s)
- Simon Schenk
- Department of Orthopaedic Surgery, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Tyler J Sagendorf
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Gina M Many
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Ana K Lira
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Luis G O de Sousa
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Dam Bae
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Michael Cicha
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Kyle S Kramer
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Michael Muehlbauer
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Andrea L Hevener
- Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, University of California, Los Angeles, CA 90095, USA
| | - R Scott Rector
- Research Service,
Harry S. Truman Memorial Veterans’ Medical Center, Columbia, MO 65201, USA
- NextGen Precision Health,
University of Missouri, Columbia, MO 65201, USA
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO 65211, USA
| | - John P Thyfault
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
- KU Diabetes Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - John P Williams
- Division of Aging Biology, National Institute on Aging, National Institutes of Health, Bethesda, MD 20898, USA
| | - Laurie J Goodyear
- Section on Integrative Physiology and Metabolism,
Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Christopher B Newgard
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Sue C Bodine
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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Zhou Y, Zhang X, Baker JS, Davison GW, Yan X. Redox signaling and skeletal muscle adaptation during aerobic exercise. iScience 2024; 27:109643. [PMID: 38650987 PMCID: PMC11033207 DOI: 10.1016/j.isci.2024.109643] [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] [Indexed: 04/25/2024] Open
Abstract
Redox regulation is a fundamental physiological phenomenon related to oxygen-dependent metabolism, and skeletal muscle is mainly regarded as a primary site for oxidative phosphorylation. Several studies have revealed the importance of reactive oxygen and nitrogen species (RONS) in the signaling process relating to muscle adaptation during exercise. To date, improving knowledge of redox signaling in modulating exercise adaptation has been the subject of comprehensive work and scientific inquiry. The primary aim of this review is to elucidate the molecular and biochemical pathways aligned to RONS as activators of skeletal muscle adaptation and to further identify the interconnecting mechanisms controlling redox balance. We also discuss the RONS-mediated pathways during the muscle adaptive process, including mitochondrial biogenesis, muscle remodeling, vascular angiogenesis, neuron regeneration, and the role of exogenous antioxidants.
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Affiliation(s)
- Yingsong Zhou
- Faculty of Sports Science, Ningbo University, Ningbo, China
| | - Xuan Zhang
- School of Wealth Management, Ningbo University of Finance and Economics, Ningbo, China
| | - Julien S. Baker
- Centre for Health and Exercise Science Research, Hong Kong Baptist University, Kowloon Tong 999077, Hong Kong
| | - Gareth W. Davison
- Sport and Exercise Sciences Research Institute, Ulster University, Belfast BT15 IED, UK
| | - Xiaojun Yan
- School of Marine Sciences, Ningbo University, Ningbo, China
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Tibúrcio FC, Leite APS, Muller KS, Pinto CG, Valentino E, Castro PATDS, Matsumura CY, de Carvalho SF, Matheus SMM. Effects of Nandrolone Decanoate on Skeletal Muscle and Neuromuscular Junction of Sedentary and Exercised Rats. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1940. [PMID: 38003989 PMCID: PMC10673219 DOI: 10.3390/medicina59111940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/03/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023]
Abstract
Background and Objectives: Nandrolone decanoate (ND) is the most widely used among the anabolic androgenic steroids (AAS), synthetic substances derived from testosterone, to improve muscular and health gains associated with exercises. The AAS leads to physical performance enhancement and presents anti-aging properties, but its abuse is associated with several adverse effects. Supraphysiological doses of AAS with or without physical exercise can cause morphological and functional alterations in neuromuscular interactions. This study aims to investigate the effects of ND supraphysiological doses in neuromuscular interactions, focusing on the soleus muscle and its neuromuscular junctions (NMJs) in rats, associated or not with physical exercise. Materials and Methods: Forty male Sprague Dawley rats were divided into four groups: sedentary and exercised groups, with or without ND at the dose of 10 mg/kg/week. The animals were treated for eight weeks, with intramuscular injections, and the soleus muscle was collected for morphological analyses. Results: The supraphysiological doses of ND in the sedentary group caused muscle degeneration, evidenced by splitting fibers, clusters of small fibers, irregular myofibrils, altered sarcomeres, an increase in collagen deposition and in the number of type I muscle fibers (slow-twitch) and central nuclei, as well as a decrease in fibers with peripheral nuclei. On the other hand, in the ND exercise group, there was an increase in the NMJs diameter with scattering of its acetylcholine receptors, although no major morphological changes were found in the skeletal muscle. Thus, the alterations caused by ND in sedentary rats were partially reversed by physical exercise. Conclusions: The supraphysiological ND exposure in the sedentary rats promoted an increase in muscle oxidative pattern and adverse morphological alterations in skeletal muscle, resulting from damage or post-injury regeneration. In the ND-exercised rats, no major morphological changes were found. Thus, the physical exercise partially reversed the alterations caused by ND in sedentary rats.
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Affiliation(s)
- Felipe Cantore Tibúrcio
- Medical School, São Paulo State University (Unesp), Botucatu 18618-687, SP, Brazil; (F.C.T.); (A.P.S.L.); (K.S.M.); (C.G.P.)
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
| | - Ana Paula Silveira Leite
- Medical School, São Paulo State University (Unesp), Botucatu 18618-687, SP, Brazil; (F.C.T.); (A.P.S.L.); (K.S.M.); (C.G.P.)
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
| | - Kevin Silva Muller
- Medical School, São Paulo State University (Unesp), Botucatu 18618-687, SP, Brazil; (F.C.T.); (A.P.S.L.); (K.S.M.); (C.G.P.)
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
| | - Carina Guidi Pinto
- Medical School, São Paulo State University (Unesp), Botucatu 18618-687, SP, Brazil; (F.C.T.); (A.P.S.L.); (K.S.M.); (C.G.P.)
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
| | - Erick Valentino
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
| | - Paula Aiello Tomé de Souza Castro
- Department of Physical Therapy, Center for Biological and Health Sciences, Federal University of São Carlos (UFSCar), São Carlos 13565-905, SP, Brazil;
| | - Cintia Yuri Matsumura
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
| | - Shelly Favorito de Carvalho
- Electron Microscopy Center, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil;
| | - Selma Maria Michelin Matheus
- Division of Anatomy, Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University (Unesp), Botucatu 18618-689, SP, Brazil; (C.Y.M.)
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Bersiner K, Park SY, Schaaf K, Yang WH, Theis C, Jacko D, Gehlert S. Resistance exercise: a mighty tool that adapts, destroys, rebuilds and modulates the molecular and structural environment of skeletal muscle. Phys Act Nutr 2023; 27:78-95. [PMID: 37583075 PMCID: PMC10440184 DOI: 10.20463/pan.2023.0021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 08/17/2023] Open
Abstract
PURPOSE Skeletal muscle regulates health and performance by maintaining or increasing strength and muscle mass. Although the molecular mechanisms in response to resistance exercise (RE) significantly target the activation of protein synthesis, a plethora of other mechanisms and structures must be involved in orchestrating the communication, repair, and restoration of homeostasis after RE stimulation. In practice, RE can be modulated by variations in intensity, continuity and volume, which affect molecular responses and skeletal muscle adaptation. Knowledge of these aspects is important with respect to planning of training programs and assessing the impact of RE training on skeletal muscle. METHODS In this narrative review, we introduce general aspects of skeletal muscle substructures that adapt in response to RE. We further highlighted the molecular mechanisms that control human skeletal muscle anabolism, degradation, repair and memory in response to acute and repeated RE and linked these aspects to major training variables. RESULTS Although RE is a key stimulus for the activation of skeletal muscle anabolism, it also induces myofibrillar damage. Nevertheless, to increase muscle mass accompanied by a corresponding adaptation of the essential substructures of the sarcomeric environment, RE must be continuously repeated. This requires the permanent engagement of molecular mechanisms that re-establish skeletal muscle integrity after each RE-induced muscle damage. CONCLUSION Various molecular regulators coordinately control the adaptation of skeletal muscle after acute and repeated RE and expand their actions far beyond muscle growth. Variations of key resistance training variables likely affect these mechanisms without affecting muscle growth.
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Affiliation(s)
- Käthe Bersiner
- Department for Biosciences of Sports, Institute of Sports Science, University of Hildesheim, Hildesheim, Germany
| | - So-Young Park
- Graduate School of Sports Medicine, CHA University, Pocheon, Republic of Korea
| | - Kirill Schaaf
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Woo-Hwi Yang
- Graduate School of Sports Medicine, CHA University, Pocheon, Republic of Korea
- Department of Medicine, General Graduate School, CHA University, Pocheon, Republic of Korea
| | - Christian Theis
- Center for Anaesthesiology, Helios University Hospital Wuppertal, Wuppertal, Germany
| | - Daniel Jacko
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Sebastian Gehlert
- Department for Biosciences of Sports, Institute of Sports Science, University of Hildesheim, Hildesheim, Germany
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Human and African ape myosin heavy chain content and the evolution of hominin skeletal muscle. Comp Biochem Physiol A Mol Integr Physiol 2023; 281:111415. [PMID: 36931425 DOI: 10.1016/j.cbpa.2023.111415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023]
Abstract
Humans are unique among terrestrial mammals in our manner of walking and running, reflecting 7 to 8 Ma of musculoskeletal evolution since diverging with the genus Pan. One component of this is a shift in our skeletal muscle biology towards a predominance of myosin heavy chain (MyHC) I isoforms (i.e. slow fibers) across our pelvis and lower limbs, which distinguishes us from chimpanzees. Here, new MyHC data from 35 pelvis and hind limb muscles of a Western gorilla (Gorilla gorilla) are presented. These data are combined with a similar chimpanzee dataset to assess the MyHC I content of humans in comparison to African apes (chimpanzees and gorillas) and other terrestrial mammals. The responsiveness of human skeletal muscle to behavioral interventions is also compared to the human-African ape differential. Humans are distinct from African apes and among a small group of terrestrial mammals whose pelvis and hind/lower limb muscle is slow fiber dominant, on average. Behavioral interventions, including immobilization, bed rest, spaceflight and exercise, can induce modest decreases and increases in human MyHC I content (i.e. -9.3% to 2.3%, n = 2033 subjects), but these shifts are much smaller than the mean human-African ape differential (i.e. 31%). Taken together, these results indicate muscle fiber content is likely an evolvable trait under selection in the hominin lineage. As such, we highlight potential targets of selection in the genome (e.g. regions that regulate MyHC content) that may play an important role in hominin skeletal muscle evolution.
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Limonium tetragonum Promotes Running Endurance in Mice through Mitochondrial Biogenesis and Oxidative Fiber Formation. Nutrients 2022; 14:nu14193904. [PMID: 36235564 PMCID: PMC9570989 DOI: 10.3390/nu14193904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/16/2022] [Accepted: 09/18/2022] [Indexed: 11/17/2022] Open
Abstract
The purpose of this study was to examine whether Limonium tetragonum, cultivated in a smart-farming system with LED lamps, could increase exercise capacity in mice. C57BL/6 male mice were orally administered vehicle or Limonium tetragonum water extract (LTE), either 30 or 100 mg/kg, and were subjected to moderate intensity treadmill exercise for 4 weeks. Running distance markedly increased in the LTE group (100 mg/kg) by 80 ± 4% compared to the vehicle group, which was accompanied by a higher proportion of oxidative fibers (6 ± 6% vs. 10 ± 4%). Mitochondrial DNA content and gene expressions related to mitochondrial biogenesis were significantly increased in LTE-supplemented gastrocnemius muscles. At the molecular level, the expression of PGC-1α, a master regulator of fast-to-slow fiber-type transition, was increased downstream of the PKA/CREB signaling pathway. LTE induction of the PKA/CREB signaling pathway was also observed in C2C12 cells, which was effectively suppressed by PKA inhibitors H89 and Rp-cAMP. Altogether, these findings indicate that LTE treatment enhanced endurance exercise capacity via an improvement in mitochondrial biosynthesis and the increases in the formation of oxidative slow-twitch fibers. Future study is warranted to validate the exercise-enhancing effect of LTE in the human.
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Andresen B, de Marees M, Schiffer T, Bloch W, Suhr F. Skeletal muscle fiber type-specific expressions of mechanosensors integrin-linked kinase, talin, and vinculin and their modulation by loading and environmental conditions in humans. FASEB J 2022; 36:e22458. [PMID: 35867073 DOI: 10.1096/fj.202101377rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 07/02/2022] [Accepted: 07/07/2022] [Indexed: 11/11/2022]
Abstract
Mechanosensors control muscle integrity as demonstrated in mice. However, no information is available in human muscle about the distribution of mechanosensors and their adaptations to mechanical loading and environmental conditions (hypoxia). Here, we hypothesized that mechanosensors show fiber-type-specific distributions and that loading and environmental conditions specifically regulate mechanosensors. We randomly subjected 28 healthy males to one of the following groups (n = 7 each) consisting of nine loading sessions within 3 weeks: normoxia moderate (NM), normoxia intensive (NI), hypoxia moderate (HM), and hypoxia intensive (HI). We took six biopsies: pre (T0), 4 h (T1), and 24 h (T2) after the third as well as 4 h (T3), 24 h (T4), and 72 h (T5) after the ninth training session. We analyzed subjects' maximal oxygen consumption (V̇O2 max), maximal power output (Pmax), muscle fiber types and cross-sectional areas (CSA), fiber-type-specific integrin-linked kinase (ILK) localizations as well as ILK, vinculin and talin protein and gene expressions in dependence on loading and environmental conditions. V̇O2 max increased upon NM and HM, Pmax upon all interventions. Fiber types did not change, whereas CSA increased upon NI and HI, but decreased upon HM. ILK showed a type 2-specific fiber type localization. ILK, vinculin, and talin protein and gene expressions differed depending on loading and environmental conditions. Our data demonstrate that mechanosensors show fiber type-specific distributions and that exercise intensities rather than environmental variables influence their profiles in human muscles. These data are the first of their kind in human muscle and indicate that mechanosensors manage the mechanosensing at a fiber-type-specific resolution and that the intensity of mechanical stimulation has a major impact.
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Affiliation(s)
- Bernhard Andresen
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Markus de Marees
- Institute of Sports Medicine and Sports Nutrition, Ruhr University Bochum, Bochum, Germany
| | - Thorsten Schiffer
- Outpatient Clinic for Sports Traumatology and Public Health Consultation, Cologne, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Frank Suhr
- Exercise Physiology Research Group, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium
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Wackerhage H, Gehlert S, Schulz H, Weber S, Ring-Dimitriou S, Heine O. Lactate Thresholds and the Simulation of Human Energy Metabolism: Contributions by the Cologne Sports Medicine Group in the 1970s and 1980s. Front Physiol 2022; 13:899670. [PMID: 35936918 PMCID: PMC9353623 DOI: 10.3389/fphys.2022.899670] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022] Open
Abstract
Today, researchers, practitioners, and physicians measure the concentration of lactate during a graded exercise test to determine thresholds related to the maximal lactate steady state (maxLass) as a sensitive measure of endurance capacity. In the 1970s and 1980s, a group of Cologne-based researchers around Wildor Hollmann, Alois Mader, and Hermann Heck developed the methodology for systematic lactate testing and introduced a 4 mmol.L−1 lactate threshold. Later, they also developed the concept of the maxLass, and Mader designed a sophisticated mathematical model of human energy metabolism during exercise. Mader`s model simulates metabolic responses to exercise based on individual variables such as maximum oxygen uptake (V˙O2max) and the maximal rate of lactate formation (νLa.max). Mader’s model predicts that the νLa.max reduces the power at the anaerobic threshold and endurance performance but that a high νLa.max is required for events with high power outputs in elite athletes. Mader’s model also assumed before the millennium that the rate of fat oxidation is explained by the difference between glycolytic pyruvate synthesis and the actual rate of pyruvate oxidation which is consistent with current opinion. Mader’s model also simulated the V˙O2max slow component in the mid-1980s. Unfortunately, several landmark studies by the Cologne group were only published in German, and as a result, contributions by the Cologne group are under-appreciated in the English-speaking world. This narrative review aims to introduce key contributions of the Cologne group to human metabolism research especially for readers who do not speak German.
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Affiliation(s)
- Henning Wackerhage
- Department of Sport and Exercise Sciences, Technical University of Munich, Munich, Germany
- *Correspondence: Henning Wackerhage, ; Sebastian Gehlert,
| | - Sebastian Gehlert
- Department of Sports Biosciences, Institute for Sports Science, University of Hildesheim, Hildesheim, Germany
- *Correspondence: Henning Wackerhage, ; Sebastian Gehlert,
| | - Henry Schulz
- Chair of Sports Medicine/Sports Biology, Technical University of Chemnitz, Chemnitz, Germany
| | | | - Susanne Ring-Dimitriou
- Department of Sport and Exercise Science, Paris Lodron University of Salzburg, Hallein, Austria
| | - Oliver Heine
- Olympic Training Centre Rhineland, Cologne, Germany
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Plotkin DL, Roberts MD, Haun CT, Schoenfeld BJ. Muscle Fiber Type Transitions with Exercise Training: Shifting Perspectives. Sports (Basel) 2021; 9:sports9090127. [PMID: 34564332 PMCID: PMC8473039 DOI: 10.3390/sports9090127] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 11/22/2022] Open
Abstract
Human muscle fibers are generally classified by myosin heavy chain (MHC) isoforms characterized by slow to fast contractile speeds. Type I, or slow-twitch fibers, are seen in high abundance in elite endurance athletes, such as long-distance runners and cyclists. Alternatively, fast-twitch IIa and IIx fibers are abundant in elite power athletes, such as weightlifters and sprinters. While cross-sectional comparisons have shown marked differences between athletes, longitudinal data have not clearly converged on patterns in fiber type shifts over time, particularly between slow and fast fibers. However, not all fiber type identification techniques are created equal and, thus, may limit interpretation. Hybrid fibers, which express more than one MHC type (I/IIa, IIa/IIx, I/IIa/IIx), may make up a significant proportion of fibers. The measurement of the distribution of fibers would necessitate the ability to identify hybrid fibers, which is best done through single fiber analysis. Current evidence using the most appropriate techniques suggests a clear ability of fibers to shift between hybrid and pure fibers as well as between slow and fast fiber types. The context and extent to which this occurs, along with the limitations of current evidence, are discussed herein.
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Affiliation(s)
- Daniel L. Plotkin
- Health Sciences Department, CUNY Lehman College, Bronx, NY 10468, USA; (D.L.P.); (B.J.S.)
| | | | - Cody T. Haun
- Fitomics, LLC., Pelham, AL 35124, USA
- Correspondence:
| | - Brad J. Schoenfeld
- Health Sciences Department, CUNY Lehman College, Bronx, NY 10468, USA; (D.L.P.); (B.J.S.)
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Verbrugge SAJ, Gehlert S, Stadhouders LEM, Jacko D, Aussieker T, M. J. de Wit G, Vogel ISP, Offringa C, Schönfelder M, Jaspers RT, Wackerhage H. PKM2 Determines Myofiber Hypertrophy In Vitro and Increases in Response to Resistance Exercise in Human Skeletal Muscle. Int J Mol Sci 2020; 21:E7062. [PMID: 32992783 PMCID: PMC7583908 DOI: 10.3390/ijms21197062] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 12/22/2022] Open
Abstract
Nearly 100 years ago, Otto Warburg investigated the metabolism of growing tissues and discovered that tumors reprogram their metabolism. It is poorly understood whether and how hypertrophying muscle, another growing tissue, reprograms its metabolism too. Here, we studied pyruvate kinase muscle (PKM), which can be spliced into two isoforms (PKM1, PKM2). This is of interest, because PKM2 redirects glycolytic flux towards biosynthetic pathways, which might contribute to muscle hypertrophy too. We first investigated whether resistance exercise changes PKM isoform expression in growing human skeletal muscle and found that PKM2 abundance increases after six weeks of resistance training, whereas PKM1 decreases. Second, we determined that Pkm2 expression is higher in fast compared to slow fiber types in rat skeletal muscle. Third, by inducing hypertrophy in differentiated C2C12 cells and by selectively silencing Pkm1 and/or Pkm2 with siRNA, we found that PKM2 limits myotube growth. We conclude that PKM2 contributes to hypertrophy in C2C12 myotubes and indicates a changed metabolic environment within hypertrophying human skeletal muscle fibers. PKM2 is preferentially expressed in fast muscle fibers and may partly contribute to the increased potential for hypertrophy in fast fibers.
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Affiliation(s)
- Sander A. J. Verbrugge
- Department for Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992 München/Munich, Germany; (S.A.J.V.); (M.S.)
| | - Sebastian Gehlert
- Department for the Biosciences of Sports, Institute of Sports Science, University of Hildesheim, Universitätsplatz 1, 31141 Hildesheim, Germany
- Department for Molecular and Cellular Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (T.A.)
| | - Lian E. M. Stadhouders
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands; (L.E.M.S.); (G.M.J.d.W.); (I.S.P.V.); (C.O.)
| | - Daniel Jacko
- Department for Molecular and Cellular Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (T.A.)
| | - Thorben Aussieker
- Department for Molecular and Cellular Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany; (D.J.); (T.A.)
| | - Gerard M. J. de Wit
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands; (L.E.M.S.); (G.M.J.d.W.); (I.S.P.V.); (C.O.)
| | - Ilse S. P. Vogel
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands; (L.E.M.S.); (G.M.J.d.W.); (I.S.P.V.); (C.O.)
| | - Carla Offringa
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands; (L.E.M.S.); (G.M.J.d.W.); (I.S.P.V.); (C.O.)
| | - Martin Schönfelder
- Department for Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992 München/Munich, Germany; (S.A.J.V.); (M.S.)
| | - Richard T. Jaspers
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands; (L.E.M.S.); (G.M.J.d.W.); (I.S.P.V.); (C.O.)
| | - Henning Wackerhage
- Department for Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992 München/Munich, Germany; (S.A.J.V.); (M.S.)
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Raz Y, Akker EB, Roest T, Riaz M, Rest O, Suchiman HED, Lakenberg N, Stassen SA, Putten M, Feskens EJM, Reinders MJT, Goeman J, Beekman M, Raz V, Slagboom PE. A data‐driven methodology reveals novel myofiber clusters in older human muscles. FASEB J 2020; 34:5525-5537. [DOI: 10.1096/fj.201902350r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/07/2020] [Accepted: 02/13/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Yotam Raz
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Erik B. Akker
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
- Leiden Computational Biology Center Leiden University Medical Center Leiden the Netherlands
- The Delft Bioinformatics Lab Delft University of Technology Delft the Netherlands
| | - Tijmen Roest
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Muhammad Riaz
- Department of Human Genetics Leiden University Medical Center Leiden the Netherlands
| | - Ondine Rest
- Division of Human Nutrition Wageningen University & Research Wageningen the Netherlands
| | - H. Eka D. Suchiman
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Nico Lakenberg
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Stefanie A. Stassen
- Section of Gerontology and Geriatrics Leiden University Medical Center Leiden the Netherlands
| | - Maaike Putten
- Department of Human Genetics Leiden University Medical Center Leiden the Netherlands
| | - Edith J. M. Feskens
- Division of Human Nutrition Wageningen University & Research Wageningen the Netherlands
| | - Marcel J. T. Reinders
- Leiden Computational Biology Center Leiden University Medical Center Leiden the Netherlands
- The Delft Bioinformatics Lab Delft University of Technology Delft the Netherlands
| | - Jelle Goeman
- Department of Medical Statistics Leiden University Medical Center Leiden the Netherlands
| | - Marian Beekman
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Vered Raz
- Department of Human Genetics Leiden University Medical Center Leiden the Netherlands
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Van Thienen R, Hespel P. Enhanced muscular oxygen extraction in athletes exaggerates hypoxemia during exercise in hypoxia. J Appl Physiol (1985) 2015; 120:351-61. [PMID: 26607244 DOI: 10.1152/japplphysiol.00210.2015] [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] [Received: 03/09/2015] [Accepted: 11/22/2015] [Indexed: 01/11/2023] Open
Abstract
High rate of muscular oxygen utilization facilitates the development of hypoxemia during exercise at altitude. Because endurance training stimulates oxygen extraction capacity, we investigated whether endurance athletes are at higher risk to developing hypoxemia and thereby acute mountain sickness symptoms during exercise at simulated high altitude. Elite athletes (ATL; n = 8) and fit controls (CON; n = 7) cycled for 20 min at 100 W (EX100W), as well as performed an incremental maximal oxygen consumption test (EXMAX) in normobaric hypoxia (0.107 inspired O2 fraction) or normoxia (0.209 inspired O2 fraction). Cardiorespiratory responses, arterial Po2 (PaO2), and oxygenation status in m. vastus lateralis [tissue oxygenation index (TOIM)] and frontal cortex (TOIC) by near-infrared spectroscopy, were measured. Muscle O2 uptake rate was estimated from change in oxyhemoglobin concentration during a 10-min arterial occlusion in m. gastrocnemius. Maximal oxygen consumption in normoxia was 70 ± 2 ml·min(-1·)kg(-1) in ATL vs. 43 ± 2 ml·min(-1·)kg(-1) in CON, and in hypoxia decreased more in ATL (-41%) than in CON (-25%, P < 0.05). Both in normoxia at PaO2 of ∼95 Torr, and in hypoxia at PaO2 of ∼35 Torr, muscle O2 uptake was twofold higher in ATL than in CON (0.12 vs. 0.06 ml·min(-1)·100 g(-1); P < 0.05). During EX100W in hypoxia, PaO2 dropped to lower (P < 0.05) values in ATL (27.6 ± 0.7 Torr) than in CON (33.5 ± 1.0 Torr). During EXMAX, but not during EX100W, TOIM was ∼15% lower in ATL than in CON (P < 0.05). TOIC was similar between the groups at any time. This study shows that maintenance of high muscular oxygen extraction rate at very low circulating PaO2 stimulates the development of hypoxemia during submaximal exercise in hypoxia in endurance-trained individuals. This effect may predispose to premature development of acute mountain sickness symptoms during exercise at altitude.
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Affiliation(s)
- Ruud Van Thienen
- Exercise Physiology Research Group, Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Peter Hespel
- Exercise Physiology Research Group, Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium
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Skeletal muscle function during exercise-fine-tuning of diverse subsystems by nitric oxide. Int J Mol Sci 2013; 14:7109-39. [PMID: 23538841 PMCID: PMC3645679 DOI: 10.3390/ijms14047109] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/17/2013] [Accepted: 03/19/2013] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle is responsible for altered acute and chronic workload as induced by exercise. Skeletal muscle adaptations range from immediate change of contractility to structural adaptation to adjust the demanded performance capacities. These processes are regulated by mechanically and metabolically induced signaling pathways, which are more or less involved in all of these regulations. Nitric oxide is one of the central signaling molecules involved in functional and structural adaption in different cell types. It is mainly produced by nitric oxide synthases (NOS) and by non-enzymatic pathways also in skeletal muscle. The relevance of a NOS-dependent NO signaling in skeletal muscle is underlined by the differential subcellular expression of NOS1, NOS2, and NOS3, and the alteration of NO production provoked by changes of workload. In skeletal muscle, a variety of highly relevant tasks to maintain skeletal muscle integrity and proper signaling mechanisms during adaptation processes towards mechanical and metabolic stimulations are taken over by NO signaling. The NO signaling can be mediated by cGMP-dependent and -independent signaling, such as S-nitrosylation-dependent modulation of effector molecules involved in contractile and metabolic adaptation to exercise. In this review, we describe the most recent findings of NO signaling in skeletal muscle with a special emphasis on exercise conditions. However, to gain a more detailed understanding of the complex role of NO signaling for functional adaptation of skeletal muscle (during exercise), additional sophisticated studies are needed to provide deeper insights into NO-mediated signaling and the role of non-enzymatic-derived NO in skeletal muscle physiology.
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Laser capture microdissection of metachromatically stained skeletal muscle allows quantification of fiber type specific gene expression. Mol Cell Biochem 2012. [PMID: 23196635 DOI: 10.1007/s11010-012-1538-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Skeletal muscle contains various myofiber types closely associated with satellite stem cells, vasculature, and neurons, thus making it difficult to perform genetic or proteomic expression analysis with sufficient cellular specificity to resolve differences at the individual cell or myofiber type level. Here, we describe the combination of a simple histochemical method capable of simultaneously identifying Type I, IIA, IIB, and IIC myofibers followed by laser capture micro-dissection (LCM) to compare the expression profiles of individual fiber types, myonuclear domains, and satellite cells in frozen muscle sections of control and atrophied muscle. Quantitative RT-PCR (qPCR) was used to verify the integrity of the cell-specific RNAs harvested after histologic staining, while qPCR for specific genes of interest was used to quantify atrophy-associated changes in mRNA. Our data demonstrate that the differential myofiber atrophy previously described by histologic means is related to differential expression of atrophy-related genes, such as MuRF1 and MAFbx (a.k.a. Atrogin-1), within different myofiber type populations. This spatially resolved molecular pathology (SRMP) technique allowed quantitation of atrophy-related gene products within individual fiber types that could not be resolved by expression analysis of the whole muscle. The present study demonstrates the importance of fiber type specific expression profiling in understanding skeletal muscle biology especially during muscle atrophy and provides a practical method of performing such research.
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