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Zhang Y, Liu C, Li Y, Xu H. Mechanism of the Mitogen-Activated Protein Kinases/Mammalian Target of Rapamycin Pathway in the Process of Cartilage Endplate Stem Cell Degeneration Induced by Tension Load. Global Spine J 2023; 13:2396-2408. [PMID: 35400210 PMCID: PMC10538332 DOI: 10.1177/21925682221085226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
STUDY DESIGN Basic Research. OBJECTIVE Intervertebral disc degeneration (IVDD) is caused by the cartilage endplate (CEP). Cartilage endplate stem cell (CESC) is involved in the recovery of CEP degeneration. Tension load (TL) contributes a lot to the initiation and progression of IVDD. This study aims to investigate the regulatory mechanism of the Mitogen-activated protein kinases/Mammalian target of rapamycin (MAPK/mTOR) pathway during TL-induced CESC degeneration. METHODS CESCs were isolated from New Zealand big-eared white female rabbits (6 months old). FX-4000T cell stress loading system was applied to establish a TL-induced degeneration model of CESCs. Western blotting was used to detect the level of mTOR pathway-related proteins and autophagy markers LC3-Ⅱ, Beclin-1, and p62 in degenerative CESCs. The expression of MAPK pathway-related proteins JNK and extracellular signal-regulated kinases (ERK) in degenerated CESCs was inhibited by cell transfection to explore whether JNK and ERK play a regulatory role in TL-induced autophagy in CESCs. RESULTS In the CESC degeneration model, the mTOR pathway was activated. After inhibition of mTOR, the autophagy level of CESCs was increased, and the degeneration of CESCs was alleviated. The MAPK pathway was also activated in the CESC degeneration model. Inhibition of JNK expression may alleviate TL-induced CEP degeneration by inhibiting Raptor phosphorylation and activating autophagy. Inhibition of ERK expression may alleviate TL-induced CEP degeneration by inhibiting mTOR phosphorylation and activating autophagy. CONCLUSION Inhibition of JNK and ERK in the MAPK signaling family alleviated TL-induced CESC degeneration by inhibiting the phosphorylation of Raptor and mTOR in the mTOR pathway.
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Affiliation(s)
- Yu Zhang
- Spine Research Center of Wannan Medical College, Department of Spine Surgery, Yijishan Hospital, The First Affiliated Hospital of Wannan Medical College, Wuhu, P.R. China
| | - Chen Liu
- Spine Research Center of Wannan Medical College, Department of Spine Surgery, Yijishan Hospital, The First Affiliated Hospital of Wannan Medical College, Wuhu, P.R. China
| | - Yu Li
- Spine Research Center of Wannan Medical College, Department of Spine Surgery, Yijishan Hospital, The First Affiliated Hospital of Wannan Medical College, Wuhu, P.R. China
| | - Hongguang Xu
- Spine Research Center of Wannan Medical College, Department of Spine Surgery, Yijishan Hospital, The First Affiliated Hospital of Wannan Medical College, Wuhu, P.R. China
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Eftestøl E, Franchi MV, Kasper S, Flück M. JNK activation in TA and EDL muscle is load-dependent in rats receiving identical excitation patterns. Sci Rep 2021; 11:16405. [PMID: 34385505 PMCID: PMC8361015 DOI: 10.1038/s41598-021-94930-x] [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: 03/16/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
As the excitation-contraction coupling is inseparable during voluntary exercise, the relative contribution of the mechanical and neural input on hypertrophy-related molecular signalling is still poorly understood. Herein, we use a rat in-vivo strength exercise model with an electrically-induced standardized excitation pattern, previously shown to induce a load-dependent increase in myonuclear number and hypertrophy, to study acute effects of load on molecular signalling. We assessed protein abundance and specific phosphorylation of the four protein kinases FAK, mTOR, p70S6K and JNK after 2, 10 and 28 min of a low- or high-load contraction, in order to assess the effects of load, exercise duration and muscle-type on their response to exercise. Specific phosphorylation of mTOR, p70S6K and JNK was increased after 28 min of exercise under the low- and high-load protocol. Elevated phosphorylation of mTOR and JNK was detectable already after 2 and 10 min of exercise, respectively, but greatest after 28 min of exercise, and JNK phosphorylation was highly load-dependent. The abundance of all four kinases was higher in TA compared to EDL muscle, p70S6K abundance was increased after exercise in a load-independent manner, and FAK and JNK abundance was reduced after 28 min of exercise in both the exercised and control muscles. In conclusion, the current study shows that JNK activation after a single resistance exercise is load-specific, resembling the previously reported degree of myonuclear accrual and muscle hypertrophy with repetition of the exercise stimulus.
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Affiliation(s)
- Einar Eftestøl
- Department of Biosciences, University of Oslo, Kristine Bonnevies hus, Blindernveien 31, 0371, Oslo, Norway.
| | - Martino V Franchi
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Stephanie Kasper
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
| | - Martin Flück
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
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Scheuren AC, D'Hulst G, Kuhn GA, Masschelein E, Wehrle E, De Bock K, Müller R. Hallmarks of frailty and osteosarcopenia in prematurely aged PolgA (D257A/D257A) mice. J Cachexia Sarcopenia Muscle 2020; 11:1121-1140. [PMID: 32596975 PMCID: PMC7432580 DOI: 10.1002/jcsm.12588] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/14/2020] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Frailty is a geriatric syndrome characterized by increased susceptibility to adverse health outcomes. One major determinant thereof is the gradual weakening of the musculoskeletal system and the associated osteosarcopenia. To improve our understanding of the underlying pathophysiology and, more importantly, to test potential interventions aimed at counteracting frailty, suitable animal models are needed. METHODS To evaluate the relevance of prematurely aged PolgA(D257A/D257A) mice as a model for frailty and osteosarcopenia, we quantified the clinical mouse frailty index in PolgA(D257A/D257A) and wild-type littermates (PolgA(+/+) , WT) with age and concertedly assessed the quantity and quality of bone and muscle tissue. Lastly, the anabolic responsiveness of skeletal muscle, muscle progenitors, and bone was assessed. RESULTS PolgA(D257A/D257A) accumulated health deficits at a higher rate compared with WT, resulting in a higher frailty index at 40 and 46 weeks of age (+166%, +278%, P < 0.0001), respectively, with no differences between genotypes at 34 weeks. Concomitantly, PolgA(D257A/D257A) displayed progressive musculoskeletal deterioration such as reduced bone and muscle mass as well as impaired functionality thereof. In addition to lower muscle weights (-14%, P < 0.05, -23%, P < 0.0001) and fibre area (-20%, P < 0.05, -22%, P < 0.0001) at 40 and 46 weeks, respectively, PolgA(D257A/D257A) showed impairments in grip strength and concentric muscle forces (P < 0.05). PolgA(D257A/D257A) mutation altered the acute response to various anabolic stimuli in skeletal muscle and muscle progenitors. While PolgA(D257A/D257A) muscles were hypersensitive to eccentric contractions as well as leucine administration, shown by larger downstream signalling response of the mechanistic target of rapamycin complex 1, myogenic progenitors cultured in vitro showed severe anabolic resistance to leucine and robust impairments in cell proliferation. Longitudinal micro-computed tomography analysis of the sixth caudal vertebrae showed that PolgA(D257A/D257A) had lower bone morphometric parameters (e.g. bone volume fraction, trabecular, and cortical thickness, P < 0.05) as well as reduced remodelling activities (e.g. bone formation and resorption rate, P < 0.05) compared with WT. When subjected to 4 weeks of cyclic loading, young but not aged PolgA(D257A/D257A) caudal vertebrae showed load-induced bone adaptation, suggesting reduced mechanosensitivity with age. CONCLUSIONS PolgA(D257A/D257A) mutation leads to hallmarks of age-related frailty and osteosarcopenia and provides a powerful model to better understand the relationship between frailty and the aging musculoskeletal system.
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Affiliation(s)
| | - Gommaar D'Hulst
- Laboratory of Exercise and HealthETH ZurichZurichSwitzerland
| | | | - Evi Masschelein
- Laboratory of Exercise and HealthETH ZurichZurichSwitzerland
| | - Esther Wehrle
- Institute for BiomechanicsETH ZurichZurichSwitzerland
| | - Katrien De Bock
- Laboratory of Exercise and HealthETH ZurichZurichSwitzerland
| | - Ralph Müller
- Institute for BiomechanicsETH ZurichZurichSwitzerland
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D'Hulst G, Palmer AS, Masschelein E, Bar-Nur O, De Bock K. Voluntary Resistance Running as a Model to Induce mTOR Activation in Mouse Skeletal Muscle. Front Physiol 2019; 10:1271. [PMID: 31636571 PMCID: PMC6787551 DOI: 10.3389/fphys.2019.01271] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/19/2019] [Indexed: 12/30/2022] Open
Abstract
Long-term voluntary resistance running has been shown to be a valid model to induce muscle growth in rodents. Moreover, the mammalian target of rapamycin complex 1 (mTORC1) is a key signaling complex regulating exercise/nutrient-induced alterations in muscle protein synthesis. How acute resistance running affects mTORC1 signaling in muscle and if resistance applied to the wheel can modulate mTORC1 activation has not yet been fully elucidated. Here, we show that both acute resistance running and acute free running activated mTORC1 signaling in the m. gastrocnemius, m. soleus, and m. plantaris, but not in m. tibialis anterior of mice when compared to sedentary controls. Furthermore, only the low threshold oxidative part in the m. gastrocnemius showed increased mTORC1 signaling upon running and acute heavy-load resistance running evoked higher downstream mTORC1 signaling in both m. soleus and m. plantaris than free running without resistance, pointing toward mechanical load as an important independent regulator of mTORC1. Collectively, in this study, we show that voluntary resistance running is an easy-to-use, time-efficient and low stress model to study acute alterations in mTORC1 signaling upon high-load muscular contractions in mice.
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Affiliation(s)
- Gommaar D'Hulst
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Andrew S Palmer
- Laboratory of Regenerative and Movement Biology, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Evi Masschelein
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Ori Bar-Nur
- Laboratory of Regenerative and Movement Biology, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
| | - Katrien De Bock
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
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Flück M, Viecelli C, Bapst AM, Kasper S, Valdivieso P, Franchi MV, Ruoss S, Lüthi JM, Bühler M, Claassen H, Hoppeler H, Gerber C. Knee Extensors Muscle Plasticity Over a 5-Years Rehabilitation Process After Open Knee Surgery. Front Physiol 2018; 9:1343. [PMID: 30337877 PMCID: PMC6178139 DOI: 10.3389/fphys.2018.01343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/06/2018] [Indexed: 01/26/2023] Open
Abstract
We investigated molecular and cellular parameters which set metabolic and mechanical functioning of knee extensor muscles in the operated and contralateral control leg of 9 patients with a chronically insufficient anterior cruciate ligament (ACL; 26.6 ± 8.3 years, 8 males, 1 female) after open reconstructive surgery (week 0), after ambulant physiotherapy under cast immobilization (week 9), succeeding rehabilitation training (up to week 26), and subsequent voluntary physical activity (week 260). Clinical indices of knee function in the operated leg were improved at 52 weeks and remained at a comparable level at week 260. CSA of the quadriceps (-18%), MCSA of muscle fibers (-24%), and capillary-to-fiber ratio (-24%) in m. vastus lateralis from the ACL insufficient leg were lower at week 0 than reference values in the contralateral leg at week 260. Slow type fiber percentage (-35%) and mitochondrial volume density (-39%) were reduced in m. vastus lateralis from the operated leg at weeks 9 and 26. Composition alterations in the operated leg exceeded those in the contralateral leg and, with the exception of the volume density of subsarcolemmal mitochondria, returned to the reference levels at week 260. Leg-specific deterioration of metabolic characteristics in the vasti from the operated leg was reflected by the down-regulation of mitochondrial respiration complex I-III markers (-41-57%) at week 9. After rehabilitation training at week 26, the specific Y397 phosphorylation of focal adhesion kinase (FAK), which is a proxy for mechano-regulation, was elevated by 71% in the operated leg but not in the contralateral leg, which had performed strengthening type exercise during ambulant physiotherapy. Total FAK protein and Y397 phosphorylation levels were lowered in both legs at week 26 resulting in positive correlations with mitochondrial volume densities and mitochondrial protein levels. The findings emphasize that a loss of mechanical and metabolic characteristics in knee extensor muscle remains detectable years after untreated ACL rupture, which may be aggravated in the post-operative phase by the deterioration of slow-oxidative characteristics after reconstruction due to insufficient load-bearing muscle activity. The reestablishment of muscle composition subsequent to years of voluntary physical activity reinforces that slow-to-fast fiber transformation is reversible in humans.
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Affiliation(s)
- Martin Flück
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Claudio Viecelli
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Andreas M Bapst
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Stephanie Kasper
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Paola Valdivieso
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Martino V Franchi
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Severin Ruoss
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jean-Marc Lüthi
- Department of Orthopedic Surgery, Inselspital Bern, Bern, Switzerland
| | - Martin Bühler
- Department of Orthopedic Surgery, Inselspital Bern, Bern, Switzerland
| | | | - Hans Hoppeler
- Department of Anatomy, University of Bern, Bern, Switzerland
| | - Christian Gerber
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.,Department of Orthopedic Surgery, Inselspital Bern, Bern, Switzerland
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Franchi MV, Ruoss S, Valdivieso P, Mitchell KW, Smith K, Atherton PJ, Narici MV, Flück M. Regional regulation of focal adhesion kinase after concentric and eccentric loading is related to remodelling of human skeletal muscle. Acta Physiol (Oxf) 2018; 223:e13056. [PMID: 29438584 DOI: 10.1111/apha.13056] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 01/31/2018] [Accepted: 02/07/2018] [Indexed: 12/31/2022]
Abstract
AIMS We assessed focal adhesion kinase (FAK) response to concentric (CON) vs eccentric (ECC) resistance training (RT) at two vastus lateralis (VL) sites, and the relationships between FAK, muscle protein synthesis (MPS) and morphological remodelling. METHODS Six young males trained both legs unilaterally 3 times/week for 8 weeks; one leg performed CON RT, the contralateral performed ECC RT. Muscle biopsies were collected after training from VL mid-belly (MID) and distal (distal) sites at 0, 4, 8 weeks. Focal adhesion kinase content and activation were evaluated by immunoblotting. MPS was assessed by deuterium oxide tracer; morphological adaptations were evaluated by ultrasound and DXA. RESULTS pY397-FAK 8 weeks levels were ~4-fold greater after ECC at the distal site compared to CON (P < .05); pY397FAK to total FAK ratio was greater in ECC vs CON at 4 (~2.2-fold, P < .05) and 8 weeks (~9-fold, P < .001) at the distal site. Meta-vinculin was found transiently increased at 4 weeks at the distal site only after ECC RT. ECC presented greater fascicle length (Lf) increases (10.5% vs 4%), whereas CON showed greater in pennation angle (PA) changes (12.3% vs 2.1%). MPS did not differ between exercise types or muscle sites at all time points. distal pY397-FAK and pY397-FAK/FAK values correlated to changes in Lf at 8 weeks (r = .76, P < .01 and r = .66, P < .05 respectively). CONCLUSION Focal adhesion kinase phosphorylation was greater at 8 weeks after ECC RT and was muscle region-specific. FAK activity correlated to contraction-dependent architectural remodelling, suggesting a potential role of FAK in orienting muscle structural changes in response to distinct mechanical stimuli.
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Affiliation(s)
- M V Franchi
- Laboratory for Muscle Plasticity, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- MRC-ARUK Centre for Musculoskeletal Ageing, Royal Derby Hospital, University of Nottingham, Derby, UK
| | - S Ruoss
- Laboratory for Muscle Plasticity, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - P Valdivieso
- Laboratory for Muscle Plasticity, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - K W Mitchell
- MRC-ARUK Centre for Musculoskeletal Ageing, Royal Derby Hospital, University of Nottingham, Derby, UK
| | - K Smith
- MRC-ARUK Centre for Musculoskeletal Ageing, Royal Derby Hospital, University of Nottingham, Derby, UK
| | - P J Atherton
- MRC-ARUK Centre for Musculoskeletal Ageing, Royal Derby Hospital, University of Nottingham, Derby, UK
| | - M V Narici
- MRC-ARUK Centre for Musculoskeletal Ageing, Royal Derby Hospital, University of Nottingham, Derby, UK
- Department of Biomedical Sciences, Institute of Physiology, University of Padua, Padua, Italy
| | - M Flück
- Laboratory for Muscle Plasticity, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Ato S, Makanae Y, Kido K, Sase K, Yoshii N, Fujita S. The effect of different acute muscle contraction regimens on the expression of muscle proteolytic signaling proteins and genes. Physiol Rep 2018; 5:5/15/e13364. [PMID: 28778992 PMCID: PMC5555890 DOI: 10.14814/phy2.13364] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 01/07/2023] Open
Abstract
Previous studies have reported that different modes of muscle contraction (i.e., eccentric or concentric contraction) with similar contraction times can affect muscle proteolytic responses. However, the effect of different contraction modes on muscle proteolytic response under the same force-time integral (FTI: contraction force × time) has not been investigated. The purpose of this study was to investigate the effect of different contraction modes, with the same FTI, on acute proteolytic signaling responses. Eleven-week-old male Sprague-Dawley rats were randomly assigned to eccentric (EC), concentric (CC), or isometric contraction (IC) groups. Different modes of muscle contraction were performed on the right gastrocnemius muscle using electrical stimulation, with the left muscle acting as a control. In order to apply an equivalent FTI, the number of stimulation sets was modified between the groups. Muscle samples were taken immediately and three hours after exercise. Phosphorylation of FoxO3a at Ser253 was significantly increased immediately after exercise compared to controls irrespective of contraction mode. The mRNA levels of the ubiquitin ligases, MuRF1, and MAFbx mRNA were unchanged by contraction mode or time. Phosphorylation of ULK1 at Ser317 (positive regulatory site) and Ser757 (negative regulatory site) was significantly increased compared to controls, immediately or 3 h after exercise, in all contraction modes. The autophagy markers (LC3B-II/I ratio and p62 expression) were unchanged, regardless of contraction mode. These data suggest that differences in contraction mode during resistance exercise with a constant FTI, are not factors in regulating proteolytic signaling in the early phase of skeletal muscle contraction.
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Affiliation(s)
- Satoru Ato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Yuhei Makanae
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kohei Kido
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kohei Sase
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Naomi Yoshii
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Satoshi Fujita
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
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Franchi MV, Reeves ND, Narici MV. Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations. Front Physiol 2017; 8:447. [PMID: 28725197 PMCID: PMC5495834 DOI: 10.3389/fphys.2017.00447] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/13/2017] [Indexed: 01/07/2023] Open
Abstract
Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively); however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT) is assumed to produce greater hypertrophy than concentric resistance training (CON RT). Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood. Thus, the present review aims to, (a) critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b) clarify the molecular mechanisms that may regulate such adaptations. We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions.
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Affiliation(s)
- Martino V Franchi
- MRC-ARUK Centre for Musculoskeletal Ageing Research, School of Medicine, University of NottinghamDerby, United Kingdom.,Laboratory for Muscle Plasticity, Department of Orthopaedics, Balgrist University Hospital, University of ZurichZürich, Switzerland
| | - Neil D Reeves
- Faculty of Science and Engineering, School of Healthcare Science, Manchester Metropolitan UniversityManchester, United Kingdom
| | - Marco V Narici
- MRC-ARUK Centre for Musculoskeletal Ageing Research, School of Medicine, University of NottinghamDerby, United Kingdom
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9
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Graham ZA, Gallagher PM, Cardozo CP. Focal adhesion kinase and its role in skeletal muscle. J Muscle Res Cell Motil 2015; 36:305-15. [PMID: 26142360 PMCID: PMC4659753 DOI: 10.1007/s10974-015-9415-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/15/2015] [Indexed: 10/23/2022]
Abstract
Skeletal muscle has a remarkable ability to respond to different physical stresses. Loading muscle through exercise, either anaerobic or aerobic, can lead to increases in muscle size and function while, conversely, the absence of muscle loading stimulates rapid decreases in size and function. A principal mediator of this load-induced change is focal adhesion kinase (FAK), a downstream non-receptor tyrosine kinase that translates the cytoskeletal stress and strain signals transmitted across the cytoplasmic membrane by integrins to activate multiple anti-apoptotic and cell growth pathways. Changes in FAK expression and phosphorylation have been found to correlate to specific developmental states in myoblast differentiation, muscle fiber formation and muscle size in response to loading and unloading. With the capability to regulate costamere formation, hypertrophy and glucose metabolism, FAK is a molecule with diverse functions that are important in regulating muscle cell health.
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Affiliation(s)
- Zachary A Graham
- Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, 130 W. Kingsbridge Rd., Bronx, NY, 10468, USA
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Christopher P Cardozo
- Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, 130 W. Kingsbridge Rd., Bronx, NY, 10468, USA.
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Herzig D, Maffiuletti NA, Eser P. The Application of Neuromuscular Electrical Stimulation Training in Various Non-neurologic Patient Populations: A Narrative Review. PM R 2015; 7:1167-1178. [DOI: 10.1016/j.pmrj.2015.03.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/24/2015] [Accepted: 03/27/2015] [Indexed: 12/16/2022]
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Popov DV, Lysenko EA, Bachinin AV, Miller TF, Kurochkina NS, Kravchenko IV, Furalyov VA, Vinogradova OL. Influence of resistance exercise intensity and metabolic stress on anabolic signaling and expression of myogenic genes in skeletal muscle. Muscle Nerve 2015; 51:434-42. [PMID: 24916884 DOI: 10.1002/mus.24314] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2014] [Indexed: 12/15/2022]
Abstract
INTRODUCTION We investigated the effect of resistance exercise intensity and exercise-induced metabolic stress on the activation of anabolic signaling and expression of myogenic genes in skeletal muscle. METHODS Ten strength-trained athletes performed high-intensity [HI, 74% of 1-repetition maximum (RM)], middle-intensity (MI, 54% 1RM), or middle-intensity (54% 1RM) no-relaxation exercise (MIR). Kinase phosphorylation level and myogenic gene expression in muscle samples were evaluated before, 45 min, 5 h, and 20 h after exercise. RESULTS The lactate concentration in MI was approximately 2-fold lower than in the 2 other sessions, and was highest in MIR. The phosphorylation level of extracellular kinase 1/2Thr202/Tyr204 after exercise was related to metabolic stress. Metabolic stress induced a decrease in myostatin mRNA expression, whereas mechano-growth factor mRNA level depended on exercise intensity. CONCLUSIONS This study demonstrates that both intensity and exercise-induced metabolic stress can be manipulated to affect muscle anabolic signaling.
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Affiliation(s)
- Daniil V Popov
- Laboratory of Exercise Physiology, Institute of Biomedical Problems, Russian Academy of Sciences, 76A Khoroshevskoe Shosse, Moscow, 123007, Russia
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12
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Wernbom M, Apro W, Paulsen G, Nilsen TS, Blomstrand E, Raastad T. Acute low-load resistance exercise with and without blood flow restriction increased protein signalling and number of satellite cells in human skeletal muscle. Eur J Appl Physiol 2014; 113:2953-65. [PMID: 24078212 DOI: 10.1007/s00421-013-2733-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 09/16/2013] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate hypertrophic signalling after a single bout of low-load resistance exercise with and without blood flow restriction (BFR). METHODS Seven subjects performed unilateral knee extensions at 30 % of their one repetition maximum. The subjects performed five sets to failure with BFR on one leg, and then repeated the same amount of work with the other leg without BFR. Biopsies were obtained from m. vastus lateralis before and 1, 24 and 48 h after exercise. RESULTS At 1-h post-exercise, phosphorylation of p70S6KThr389 and p38MAPKThr180/Tyr182 was elevated in the BFR leg, but not in the free-flow leg. Phospho-p70S6KThr389 was elevated three- to fourfold in both legs at 24-h post-exercise, but back to baseline at 48 h. The number of visible satellite cells (SCs) per muscle fibre was increased for all post-exercise time points and in both legs (33–53 %). The proportion of SCs with cytoplasmic extensions was elevated at 1-h post in the BFR leg and the number of SCs positive for myogenin and/or MyoD was increased at 1- and 24-h post-exercise for both legs combined. CONCLUSION Acute low-load resistance exercise with BFR resulted in early (1 h) and late (24 h) enhancement of phospho-p70S6KThr389, an early response of p38MAPK, and an increased number of SCs per muscle fibre. Enhanced phospho-p70S6KThr389 at 24-h post-exercise and increases in SC numbers were seen also in the free-flow leg. Implications of these findings for the hypertrophic effects of fatiguing low-load resistance exercise with and without BFR are discussed.
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