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Benitez B, Kwak M, Succi PJ, Mitchinson C, Bergstrom HC. No sex differences in time-to-task failure and neuromuscular patterns of response during submaximal, bilateral, isometric leg extensions. Eur J Appl Physiol 2024:10.1007/s00421-024-05508-0. [PMID: 38772923 DOI: 10.1007/s00421-024-05508-0] [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: 11/13/2023] [Accepted: 05/13/2024] [Indexed: 05/23/2024]
Abstract
BACKGROUND In general, it has been suggested that females are more fatigue-resistant than males, with the magnitude of difference being most pronounced during low-intensity sustained contractions. However, the mechanisms for the apparent sex difference have not yet been fully elucidated in the literature. This study aimed to examine sex-related differences in fatigability and patterns of neuromuscular responses for surface electromyographic (sEMG) and mechanomyographic (sMMG) amplitude and frequency (MPF) characteristics during a sustained submaximal bilateral, isometric leg extension muscle action. METHODS A sample of 20 young recreationally active males and females with previous resistance training experience performed a sustained, submaximal, bilateral isometric leg extension until task failure. Time-to-task failure was compared using a nonparametric bootstrap of the 95% confidence interval for the mean difference between males and females. Additionally, patterns of response for sEMG and sMMG amplitude and MPF of the dominant limb were examined using linear mixed effect models. RESULTS There were no differences in time-to-task failure between males and females. Additionally, neuromuscular responses revealed similar patterns of responses between males and females. Interestingly, sEMG amplitude and sMMG amplitude and MPF all revealed non-linear responses, while sEMG MPF demonstrated linear responses. CONCLUSION These data revealed that time-to-task failure was not different between males and females during sustained submaximal bilateral, isometric leg extension. Interestingly, the parallel, non-linear, increases in sEMG and sMMG amplitude may indicate fatigue induced increases in motor unit recruitment, while the parallel decreases in sMMG MPF may be explained by the intrinsic properties of later recruited motor units, which may have inherently lower firing rates than those recruited earlier.
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Affiliation(s)
- Brian Benitez
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40536, USA.
| | - Minyoung Kwak
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40536, USA
| | - Pasquale J Succi
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40536, USA
| | - Clara Mitchinson
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40536, USA
| | - Haley C Bergstrom
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, 40536, USA
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2
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Watanabe D, Nishi M, Liu F, Bian Y, Takeshima H. Ca 2+ storage function is altered in the sarcoplasmic reticulum of skeletal muscle lacking mitsugumin 23. Am J Physiol Cell Physiol 2024; 326:C795-C809. [PMID: 38223925 DOI: 10.1152/ajpcell.00440.2023] [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: 09/11/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
Mitsugumin 23 (MG23) has been identified as a ball-shaped cation channel in the sarcoplasmic reticulum (SR) but its physiological role remains unclear. This study aimed to examine the contribution of MG23 to Ca2+ storage function in skeletal muscle by using Mg23-knockout (Mg23-/-) mice. There was no difference in the isometric specific force of the extensor digitorum longus (EDL) and soleus (SOL) muscles between Mg23-/- and wild-type (Wt) mice. In Mg23-/- mice, the calsequestrin 2 content in the EDL muscle and SR Ca2+-ATPase 2 content in the SOL were increased. We have examined SR and myofibril functions using mechanically skinned fibers and determined their fiber types based on the response to Sr2+, which showed that Mg23-/- mice, compared with Wt, had: 1) elevated total Ca2+ content in the membranous components including SR, mitochondria, and transverse tubular system referred to as endogenous Ca2+ content, in both type I and II fibers of the EDL and SOL; 2) increased maximal Ca2+ content in both type I and II fibers of the EDL and SOL; 3) decreased SR Ca2+ leakage in type I fibers of the SOL; and 4) enhanced SR Ca2+ uptake in type I fibers of the SOL, although myofibril function was not different in both type I and II fibers of the SOL and EDL muscles. These results suggest that MG23 decreases SR Ca2+ storage in both type I and type II fibers, likely due to increased SR Ca2+ leakage.NEW & NOTEWORTHY The function of calcium storage within sarcoplasmic reticulum (SR) plays a pivotal role in influencing the health and disease states of skeletal muscle. In the present study, we demonstrated that mitsgumin 23, a novel non-selective cation channel, modifies SR Ca2+ storage in skeletal muscle fibers. These findings provide valuable insights into the physiological regulation of Ca2+ in skeletal muscle, offering significant potential for uncovering the mechanisms underlying muscle fatigue, muscle adaptation, and muscle diseases.
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Affiliation(s)
- Daiki Watanabe
- Graduate School of Sport and Health Sciences, Osaka University of Health and Sport Sciences, Osaka, Japan
| | - Miyuki Nishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Feng Liu
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yuhan Bian
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroshi Takeshima
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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3
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Tripp TR, McDougall RM, Frankish BP, Wiley JP, Lun V, MacInnis MJ. Contraction intensity affects NIRS-derived skeletal muscle oxidative capacity but not its relationships to mitochondrial protein content or aerobic fitness. J Appl Physiol (1985) 2024; 136:298-312. [PMID: 38059287 DOI: 10.1152/japplphysiol.00342.2023] [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: 05/30/2023] [Revised: 11/16/2023] [Accepted: 12/02/2023] [Indexed: 12/08/2023] Open
Abstract
To further refine the near-infrared spectroscopy (NIRS)-derived measure of skeletal muscle oxidative capacity in humans, we sought to determine whether the exercise stimulus intensity affected the τ value and/or influenced the magnitude of correlations with in vitro measures of mitochondrial content and in vivo indices of exercise performance. Males (n = 12) and females (n = 12), matched for maximal aerobic fitness per fat-free mass, completed NIRS-derived skeletal muscle oxidative capacity tests for the vastus lateralis following repeated contractions at 40% (τ40) and 100% (τ100) of maximum voluntary contraction, underwent a skeletal muscle biopsy of the same muscle, and performed multiple intermittent isometric knee extension tests to task failure to establish critical torque (CT). The value of τ100 (34.4 ± 7.0 s) was greater than τ40 (24.2 ± 6.9 s, P < 0.001), but the values were correlated (r = 0.688; P < 0.001). The values of τ40 (r = -0.692, P < 0.001) and τ100 (r = -0.488, P = 0.016) correlated with myosin heavy chain I percentage and several markers of mitochondrial content, including COX II protein content in whole muscle (τ40: r = -0.547, P = 0.006; τ100: r = -0.466, P = 0.022), type I pooled fibers (τ40: r = -0.547, P = 0.006; τ100: r = -0.547, P = 0.006), and type II pooled fibers (τ40: r = -0.516, P = 0.009; τ100: r = -0.635, P = 0.001). The value of τ40 (r = -0.702, P < 0.001), but not τ100 (r = -0.378, P = 0.083) correlated with critical torque (CT); however, neither value correlated with W' (τ40: r = 0.071, P = 0.753; τ100: r = 0.054, P = 0.812). Overall, the NIRS method of assessing skeletal muscle oxidative capacity is sensitive to the intensity of skeletal muscle contraction but maintains relationships to whole body fitness, isolated limb critical intensity, and mitochondrial content regardless of intensity.NEW & NOTEWORTHY Skeletal muscle oxidative capacity measured using near-infrared spectroscopy (NIRS) was lower following high-intensity compared with low-intensity isometric knee extension contractions. At both intensities, skeletal muscle oxidative capacity was correlated with protein markers of mitochondrial content (in whole muscle and pooled type I and type II muscle fibers) and critical torque. These findings highlight the importance of standardizing contraction intensity while using the NIRS method with isometric contractions and further demonstrate its validity.
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Affiliation(s)
- Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | | | | | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Faculty of Kinesiology, University of Calgary Sport Medicine Centre, Calgary, Alberta, Canada
| | - Victor Lun
- Faculty of Kinesiology, University of Calgary Sport Medicine Centre, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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4
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Cogliati M, Cudicio A, Benedini M, Cabral HV, Negro F, Reggiani C, Orizio C. Influence of age on force and re-lengthening dynamics after tetanic stimulation withdrawal in the tibialis anterior muscle. Eur J Appl Physiol 2023; 123:1825-1836. [PMID: 37071199 PMCID: PMC10363076 DOI: 10.1007/s00421-023-05198-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
PURPOSE During alternate movements across a joint, the changeover from one direction of rotation to the opposite may be influenced by the delay and rate of tension reduction and the compliance to re-lengthening of the previously active muscle group. Given the aging process may affect the above-mentioned factors, this work aimed to compare the dynamics of both the ankle torque decline and muscle re-lengthening, mirrored by mechanomyogram (MMG), in the tibialis anterior because of its important role in gait. METHODS During the relaxation phase, after a supramaximal 35 Hz stimulation applied at the superficial motor point, in 20 young (Y) and 20 old (O) subjects, the torque (T) and MMG dynamics characteristics were measured. RESULTS The T and MMG analysis provided: (I) the beginning of the decay after cessation of stimulation (T: 22.51 ± 5.92 ms [Y] and 51.35 ± 15.21 ms [O]; MMG: 27.38 ± 6.93 ms [Y] and 61.41 ± 18.42 ms [O]); (II) the maximum rate of reduction (T: - 110.4 ± 45.56 Nm/s [Y] and - 52.72 ± 32.12 Nm/s [O]; MMG: - 24.47 ± 10.95 mm/s [Y] and - 13.76 ± 6.54 mm/s [O]); (III) the muscle compliance, measuring the MMG reduction of every 10% reduction of torque (bin 20-10%: 15.69 ± 7.5[Y] and 10.8 ± 3.3 [O]; bin 10-0%: 22.12 ± 10.3 [Y] and 17.58 ± 5.6 [O]). CONCLUSION Muscle relaxation results are different in Y and O and can be monitored by a non-invasive method measuring physiological variables of torque and re-lengthening dynamics at the end of the electromechanical coupling previously induced by the neuromuscular stimulation.
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Affiliation(s)
- M. Cogliati
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - A. Cudicio
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - M. Benedini
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - H. V. Cabral
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - F. Negro
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
- Centre of Research on the Neuromuscular Function and the Adapted Motor Activity, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
| | - C. Reggiani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Science and Research Center, ZRS, Koper, Slovenia
| | - C. Orizio
- Department of Clinical and Experimental Sciences, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
- Centre of Research on the Neuromuscular Function and the Adapted Motor Activity, University of Brescia Viale Europa, 11, 25123 Brescia, Italy
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Lu T, Zhu Y, Guo J, Mo Z, Zhou Q, Hu CY, Wang C. MDFI regulates fast-to-slow muscle fiber type transformation via the calcium signaling pathway. Biochem Biophys Res Commun 2023; 671:215-224. [PMID: 37307704 DOI: 10.1016/j.bbrc.2023.05.053] [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: 04/23/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 06/14/2023]
Abstract
Muscle fiber is the basic unit of skeletal muscle with strong self-adaptability, and its type is closely related to meat quality. Myod family inhibitor (Mdfi) has the function of regulating myogenic regulatory factors during cell differentiation, but how Mdfi regulates muscle fiber type transformation in myoblasts is still unclear. In the present study, we constructed overexpressing and interfering with Mdfi C2C12 cell models by lipofection. The immunofluorescence, quantitative real-time PCR (qPCR), and western blot results show that the elevated MDFI promoted mitochondrial biogenesis, aerobic metabolism and the calcium level by activating CaMKK2 and AMPK phosphorylation and then stimulated the conversion of C2C12 cells from fast glycolytic to slow oxidative type. In addition, after inhibiting IP3R and RYR channels, the higher MDFI reversed the blockage of calcium release from the endoplasmic reticulum by calcium channel receptor inhibitors and increased intracellular calcium levels. Therefore, we propose that the higher MDFI promotes muscle fiber types conversion through the calcium signaling pathway. These findings further broaden our understanding of the regulatory mechanism of MDFI in muscle fiber type transformation. Furthermore, our results suggest potential therapeutic targets for skeletal muscle and metabolic-related diseases.
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Affiliation(s)
- Tingting Lu
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yifan Zhu
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Jiali Guo
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Ziyuan Mo
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Quan Zhou
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Ching Yuan Hu
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Chong Wang
- National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangdong Laboratory for Lingnan Modern Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China.
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6
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O'Bryan SM, Connor KR, Drummer DJ, Lavin KM, Bamman MM. Considerations for Sex-Cognizant Research in Exercise Biology and Medicine. Front Sports Act Living 2022; 4:903992. [PMID: 35721874 PMCID: PMC9204149 DOI: 10.3389/fspor.2022.903992] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/17/2022] [Indexed: 12/15/2022] Open
Abstract
As the fields of kinesiology, exercise science, and human movement developed, the majority of the research focused on male physiology and extrapolated findings to females. In the medical sphere, basing practice on data developed in only males resulted in the removal of drugs from the market in the late 1990s due to severe side effects (some life-threatening) in females that were not observed in males. In response to substantial evidence demonstrating exercise-induced health benefits, exercise is often promoted as a key modality in disease prevention, management, and rehabilitation. However, much like the early days of drug development, a historical literature knowledge base of predominantly male studies may leave the exercise field vulnerable to overlooking potentially key biological differences in males and females that may be important to consider in prescribing exercise (e.g., how exercise responses may differ between sexes and whether there are optimal approaches to consider for females that differ from conventional approaches that are based on male physiology). Thus, this review will discuss anatomical, physiological, and skeletal muscle molecular differences that may contribute to sex differences in exercise responses, as well as clinical considerations based on this knowledge in athletic and general populations over the continuum of age. Finally, this review summarizes the current gaps in knowledge, highlights the areas ripe for future research, and considerations for sex-cognizant research in exercise fields.
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Affiliation(s)
- Samia M. O'Bryan
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kathleen R. Connor
- UAB Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Devin J. Drummer
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kaleen M. Lavin
- The Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
| | - Marcas M. Bamman
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
- The Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
- *Correspondence: Marcas M. Bamman
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7
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Tripp TR, Frankish BP, Lun V, Wiley JP, Shearer J, Murphy RM, MacInnis MJ. Time course and fibre type-dependent nature of calcium-handling protein responses to sprint interval exercise in human skeletal muscle. J Physiol 2022; 600:2897-2917. [PMID: 35556249 DOI: 10.1113/jp282739] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Sprint interval training (SIT) has been shown to cause fragmentation of the sarcoplasmic reticulum calcium-release channel, ryanodine receptor 1 (RyR1) 24 hours post-exercise, which may act as a signal for mitochondrial biogenesis. In this study, we examined the time course of RyR1 fragmentation in human whole muscle and pooled type I and type II skeletal muscle fibres following a single session of SIT. Full-length RyR1 protein content was significantly lower than pre-exercise by 6 h post-SIT in whole muscle, and fragmentation was detectable in type II but not type I fibres, though to a lesser extent than in whole muscle. The peak in PGC1A mRNA expression occurred earlier than RyR1 fragmentation. The increased temporal resolution and fibre type-specific responses for RyR1 fragmentation provide insights into its importance to mitochondrial biogenesis in humans. ABSTRACT Sprint interval training (SIT) causes fragmentation of the skeletal muscle sarcoplasmic reticulum Ca2+ release channel, ryanodine receptor 1 (RyR1), 24h post-exercise, potentially signaling mitochondrial biogenesis by increasing cytosolic [Ca2+ ]. Yet, the time course and skeletal muscle fibre type-specific patterns of RyR1 fragmentation following a session of SIT remain unknown. Ten participants (n = 4 females; n = 6 males) performed a session of SIT (6 × 30 s "all-out" with 4.5 min rest after each sprint) with vastus lateralis muscle biopsy samples collected before and 3, 6, and 24h after exercise. In whole muscle, full-length RyR1 protein content was significantly reduced 6 h (mean [SD]; -38 [38]%; p<0.05) and 24 h post-SIT (-30 [48]%; p<0.05) compared to pre-exercise. Examining each participant's largest response in pooled samples, full-length RyR1 protein content was reduced in type II (-26 [30]%; p<0.05) but not type I fibres (-11 [40]%; p>0.05). 3h post-SIT, there was also a decrease in SERCA1 in type II fibres (-23 [17]%; p<0.05) and SERCA2a in type I fibres (-19 [21]%; p<0.05), despite no time effect for either protein in whole muscle samples (p>0.05). PGC1A mRNA content was elevated 3h and 6h post-SIT (5.3- and 3.7-fold change from pre, respectively; p<0.05 for both), but peak PGC1A mRNA expression was not significantly correlated with peak RyR1 fragmentation (r2 = 0.10; p>0.05). In summary, altered Ca2+ -handling protein expression, which occurs primarily in type II muscle fibres, may influence signals for mitochondrial biogenesis as early as 3-6 h post-SIT in humans. Abstract figure legend Western blotting was performed on whole muscle and pooled type I and II muscle fibre preparations derived from human vastus lateralis muscle biopsy samples collected before and after a single session of sprint interval training (SIT). Full-length ryanodine receptor 1 (RyR1) protein content was reduced 6 and 24 h post-exercise in whole muscle samples compared to baseline, despite a heterogeneous time course among individuals. This RyR1 fragmentation proceeded and outlasted the increase in peroxisome proliferator-activated γ receptor coactivator 1α (PGC1A) mRNA expression. When examining the time point of each individual's peak response, RyR1 fragmentation was evident in type II, but not type I, muscle fibres. These findings suggest that, in humans, mitochondrial biogenesis could be influenced by RyR1 fragmentation 3-6 h post-SIT in a fibre type-dependent manner. Created with BioRender.com. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Barnaby P Frankish
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Victor Lun
- University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jane Shearer
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robyn M Murphy
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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Barclay CJ, Launikonis BS. A mathematical model to quantify RYR Ca2+ leak and associated heat production in resting human skeletal muscle fibers. J Gen Physiol 2022; 154:213077. [PMID: 35311921 PMCID: PMC9037342 DOI: 10.1085/jgp.202112994] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/06/2022] [Indexed: 02/02/2023] Open
Abstract
Cycling of Ca2+ between the sarcoplasmic reticulum (SR) and myoplasm is an important component of skeletal muscle resting metabolism. As part of this cycle, Ca2+ leaks from the SR into the myoplasm and is pumped back into the SR using ATP, which leads to the consumption of O2 and generation of heat. Ca2+ may leak through release channels or ryanodine receptors (RYRs). RYR Ca2+ leak can be monitored in a skinned fiber preparation in which leaked Ca2+ is pumped into the t-system and measured with a fluorescent dye. However, accurate quantification faces a number of hurdles. To overcome them, we developed a mathematical model of Ca2+ movement in these preparations. The model incorporated Ca2+ pumps that move Ca2+ from the myoplasm to the SR and from the junctional space (JS) to the t-system, Ca2+ buffering by EGTA in the JS and myoplasm and by buffers in the SR, and Ca2+ leaks from the SR into the JS and myoplasm and from the t-system into the myoplasm. The model accurately simulated Ca2+ uptake into the t-system, the relationship between myoplasmic [Ca2+] and steady-state t-system [Ca2+], and the effect of blocking RYR Ca2+ leak on t-system Ca2+ uptake. The magnitude of the leak through the RYRs would contribute ∼5% of the resting heat production of human muscle. In normal resting fibers, RYR Ca2+ leak makes a small contribution to resting metabolism. RYR-focused pathologies have the potential to increase RYR Ca2+ leak and the RYR leak component of resting metabolism.
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9
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Xu H, Ranjit R, Richardson A, Van Remmen H. Muscle mitochondrial catalase expression prevents neuromuscular junction disruption, atrophy, and weakness in a mouse model of accelerated sarcopenia. J Cachexia Sarcopenia Muscle 2021; 12:1582-1596. [PMID: 34559475 PMCID: PMC8718066 DOI: 10.1002/jcsm.12768] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/22/2021] [Accepted: 07/10/2021] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Oxidative stress and damage are associated with a number of ageing phenotypes, including age-related loss of muscle mass and reduced contractile function (sarcopenia). Our group and others have reported loss of neuromuscular junction (NMJ) integrity and increased denervation as initiating factors in sarcopenia, leading to mitochondrial dysfunction, generation of reactive oxygen species and peroxides, and loss of muscle mass and weakness. Previous studies from our laboratory show that denervation-induced skeletal muscle mitochondrial peroxide generation is highly correlated to muscle atrophy. Here, we directly test the impact of scavenging muscle mitochondrial hydrogen peroxide on the structure and function of the NMJ and muscle mass and function in a mouse model of denervation-induced muscle atrophy CuZnSOD (Sod1-/- mice, Sod1KO). METHODS Whole-body Sod1KO mice were crossed to mice with increased expression of human catalase (MCAT) targeted specifically to mitochondria in skeletal muscle (mMCAT mice) to determine the impact of reduced hydrogen peroxide levels on key targets of sarcopenia, including mitochondrial function, NMJ structure and function, and indices of muscle mass and function. RESULTS Female adult (~12-month-old) Sod1KO mice show a number of sarcopenia-related phenotypes in skeletal muscle including reduced mitochondrial oxygen consumption and elevated reactive oxygen species generation, fragmentation, and loss of innervated NMJs (P < 0.05), a 30% reduction in muscle mass (P < 0.05), a 36% loss of force generation (P < 0.05), and a loss of exercise capacity (305 vs. 709 m in wild-type mice, P < 0.05). Muscle from Sod1KO mice also shows a 35% reduction in sarco(endo)plasmic reticulum ATPase activity (P < 0.05), changes in the amount of calcium-regulating proteins, and altered fibre-type composition. In contrast, increased catalase expression in the mMCAT × Sod1KO mice completely prevents the mitochondrial and NMJ-related phenotypes and maintains muscle mass and force generation. The reduction in exercise capacity is also partially inhibited (~35%, P < 0.05), and the loss of fibre cross-sectional area is inhibited by ~50% (P < 0.05). CONCLUSIONS Together, these striking findings suggest that scavenging of mitochondrial peroxide generation by mMCAT expression efficiently prevents mitochondrial dysfunction and NMJ disruption associated with denervation-induced atrophy and weakness, supporting mitochondrial H2 O2 as an important effector of NMJ alterations that lead to phenotypes associated with sarcopenia.
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Affiliation(s)
- Hongyang Xu
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Rojina Ranjit
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Arlan Richardson
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Holly Van Remmen
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma City VA Medical Center, Oklahoma City, OK, USA
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10
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Jayawardena TU, Kim SY, Jeon YJ. Sarcopenia; functional concerns, molecular mechanisms involved, and seafood as a nutritional intervention - review article. Crit Rev Food Sci Nutr 2021; 63:1983-2003. [PMID: 34459311 DOI: 10.1080/10408398.2021.1969889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The fundamental basis for the human function is provided by skeletal muscle. Advancing age causes selective fiber atrophy, motor unit loss, and hybrid fiber formation resulting in hampered mass and strength, thus referred to as sarcopenia. Influence on the loss of independence of aged adults, contribute toward inclined healthcare costs conveys the injurious impact. The current understating of age-related skeletal muscle changes are addressed in this review, and further discusses mechanisms regulating protein turnover, although they do not completely define the process yet. Moreover, the reduced capacity of muscle regeneration due to impairment of satellite cell activation and proliferation with neuronal, immunological, hormonal factors were brought into the light of attention. Nevertheless, complete understating of sarcopenia requires disentangling it from disuse and disease. Nutritional intervention is considered a potentially preventable factor contributing to sarcopenia. Seafood is a crucial player in the fight against hunger and malnutrition, where it consists of macro and micronutrients. Hence, the review shed light on seafood as a nutritional intrusion in the treatment and prevention of sarcopenia. Understanding multiple factors will provide therapeutic targets in the prevention, treatment, and overcoming adverse effects of sarcopenia.
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Affiliation(s)
- Thilina U Jayawardena
- Department of Marine Life Sciences, Jeju National University, Jeju, Republic of Korea
| | - Seo-Young Kim
- Division of Practical Application, Honam National Institute of Biological Resources, Mokpo-si, Korea
| | - You-Jin Jeon
- Department of Marine Life Sciences, Jeju National University, Jeju, Republic of Korea.,Marine Science Institute, Jeju National University, Jeju, Jeju Self-Governing Province, Republic of Korea
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11
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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12
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Watanabe D, Wada M. Orthograde signal of dihydropyridine receptor increases Ca 2+ leakage after repeated contractions in rat fast-twitch muscles in vivo. Am J Physiol Cell Physiol 2021; 320:C806-C821. [PMID: 33596151 DOI: 10.1152/ajpcell.00364.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/10/2021] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to investigate the mechanism underlying sarcoplasmic reticulum (SR) Ca2+ leakage after in vivo contractions. Rat gastrocnemius muscles were electrically stimulated in vivo, and then mechanically skinned fibers and SR microsomes were prepared from the muscles excised 30 min after repeated high-intensity contractions. The mechanically skinned fibers maintained the interaction between dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs), whereas the SR microsomes did not. Interestingly, skinned fibers from the stimulated muscles showed increased SR Ca2+ leakage, whereas Ca2+ leakage decreased in SR microsomes from the stimulated muscles. To enhance the orthograde signal of DHPRs, SR Ca2+ leakage in the skinned fiber was measured 1) under a continuously depolarized condition and 2) in the presence of nifedipine. As a result, in either of the two conditions, SR Ca2+ leakage in the rested fibers reached a level similar to that in the stimulated fibers. Furthermore, the increased SR Ca2+ leakage from the stimulated fibers was alleviated by treatment with 1 mM tetracaine (Tet) but not by treatment with 3 mM free Mg2+ (3 Mg). Tet exerted a greater inhibitory effect on the DHPR signal to RyR than 3 Mg, although their inhibitory effects on RyR were almost similar. These results suggest that the increased Ca2+ leakage after muscle contractions is mainly caused by the orthograde signal of DHPRs to RyRs.
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Affiliation(s)
- Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Masanobu Wada
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
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13
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Loss of α-actinin-3 during human evolution provides superior cold resilience and muscle heat generation. Am J Hum Genet 2021; 108:446-457. [PMID: 33600773 PMCID: PMC8008486 DOI: 10.1016/j.ajhg.2021.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022] Open
Abstract
The protein α-actinin-3 expressed in fast-twitch skeletal muscle fiber is absent in 1.5 billion people worldwide due to homozygosity for a nonsense polymorphism in ACTN3 (R577X). The prevalence of the 577X allele increased as modern humans moved to colder climates, suggesting a link between α-actinin-3 deficiency and improved cold tolerance. Here, we show that humans lacking α-actinin-3 (XX) are superior in maintaining core body temperature during cold-water immersion due to changes in skeletal muscle thermogenesis. Muscles of XX individuals displayed a shift toward more slow-twitch isoforms of myosin heavy chain (MyHC) and sarcoplasmic reticulum (SR) proteins, accompanied by altered neuronal muscle activation resulting in increased tone rather than overt shivering. Experiments on Actn3 knockout mice showed no alterations in brown adipose tissue (BAT) properties that could explain the improved cold tolerance in XX individuals. Thus, this study provides a mechanism for the positive selection of the ACTN3 X-allele in cold climates and supports a key thermogenic role of skeletal muscle during cold exposure in humans.
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14
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Deshmukh AS, Steenberg DE, Hostrup M, Birk JB, Larsen JK, Santos A, Kjøbsted R, Hingst JR, Schéele CC, Murgia M, Kiens B, Richter EA, Mann M, Wojtaszewski JFP. Deep muscle-proteomic analysis of freeze-dried human muscle biopsies reveals fiber type-specific adaptations to exercise training. Nat Commun 2021; 12:304. [PMID: 33436631 PMCID: PMC7803955 DOI: 10.1038/s41467-020-20556-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 12/01/2020] [Indexed: 01/29/2023] Open
Abstract
Skeletal muscle conveys several of the health-promoting effects of exercise; yet the underlying mechanisms are not fully elucidated. Studying skeletal muscle is challenging due to its different fiber types and the presence of non-muscle cells. This can be circumvented by isolation of single muscle fibers. Here, we develop a workflow enabling proteomics analysis of pools of isolated muscle fibers from freeze-dried human muscle biopsies. We identify more than 4000 proteins in slow- and fast-twitch muscle fibers. Exercise training alters expression of 237 and 172 proteins in slow- and fast-twitch muscle fibers, respectively. Interestingly, expression levels of secreted proteins and proteins involved in transcription, mitochondrial metabolism, Ca2+ signaling, and fat and glucose metabolism adapts to training in a fiber type-specific manner. Our data provide a resource to elucidate molecular mechanisms underlying muscle function and health, and our workflow allows fiber type-specific proteomic analyses of snap-frozen non-embedded human muscle biopsies.
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Affiliation(s)
- A S Deshmukh
- The Novo Nordisk Foundation Center for Protein Research, Clinical Proteomics, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
- The Novo Nordisk Foundation Center for Basic Metablic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - D E Steenberg
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - M Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - J B Birk
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - J K Larsen
- The Novo Nordisk Foundation Center for Basic Metablic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A Santos
- The Novo Nordisk Foundation Center for Protein Research, Clinical Proteomics, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - J R Hingst
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - C C Schéele
- The Novo Nordisk Foundation Center for Basic Metablic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- The Centre of Inflammation and Metabolism and Centre for Physical Activity Research Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - M Murgia
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, Germany
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - B Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - E A Richter
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - M Mann
- The Novo Nordisk Foundation Center for Protein Research, Clinical Proteomics, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - J F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
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15
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Tobias IS, Galpin AJ. Moving human muscle physiology research forward: an evaluation of fiber type-specific protein research methodologies. Am J Physiol Cell Physiol 2020; 319:C858-C876. [DOI: 10.1152/ajpcell.00107.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Human skeletal muscle is a heterogeneous tissue composed of multiple fiber types that express unique contractile and metabolic properties. While analysis of mixed fiber samples predominates and holds value, increasing attention has been directed toward studying proteins segregated by fiber type, a methodological distinction termed “fiber type-specific.” Fiber type-specific protein studies have the advantage of uncovering key molecular effects that are often missed in mixed fiber homogenate studies but also require greater time and resource-intensive methods, particularly when applied to human muscle. This review summarizes and compares current methods used for fiber type-specific protein analysis, highlighting their advantages and disadvantages for human muscle studies, in addition to recent advances in these techniques. These methods can be grouped into three categories based on the initial processing of the tissue: 1) muscle-specific fiber homogenates, 2) cross sections of fiber bundles, and 3) isolated single fibers, with various subtechniques for performing fiber type identification and protein quantification. The relative implementation for each unique methodological approach is analyzed from 83 fiber type-specific studies of proteins in live human muscle found in the literature to date. These studies have investigated several proteins involved in a wide range of cellular functions that are important to muscle tissue. The second half of this review summarizes key findings from this ensemble of fiber type-specific human protein studies. We highlight examples of where this analytical approach has helped to improve understanding of important physiological topics such as insulin sensitivity, muscle hypertrophy, muscle fatigue, and adaptation to different exercise programs.
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Affiliation(s)
- Irene S. Tobias
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Andrew J. Galpin
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
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16
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Zhao L, Zhang X, Luo Q, Hou C, Xu J, Liu J. Engineering Nonmechanical Protein-Based Hydrogels with Highly Mechanical Properties: Comparison with Natural Muscles. Biomacromolecules 2020; 21:4212-4219. [PMID: 32886490 DOI: 10.1021/acs.biomac.0c01002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The elegant elasticity and toughness of muscles that are controlled by myofilament sliding, highly elastic springlike properties of titin, and Ca2+-induced conformational change of the troponin complex have been a source of inspiration to develop advanced materials for simulating elastic muscle motion. Herein, a highly stretchable protein hydrogel is developed to mimic the structure and motion of muscles through the combination of protein folding-unfolding and molecular sliding. It has been shown that the protein bovine serum albumin is covalently cross-linked, together penetrated with alginate chains to construct polyprotein-based hydrogels, where polyproteins can act as the elastic spring titin via protein folding-unfolding and also achieve tunable sliding facilitated by alginate due to their reversible noncovalent interactions, thus providing desired mechanical properties such as stretchability, resilience, and strength. Notably, these biomaterials can achieve the breaking strain of up to 1200% and show massive energy dissipation. A pronounced expansion-contraction phenomenon is also observed on the macroscopic scale, and the Ca2+-induced contraction process may help to improve our understanding of muscle movement. Overall, these excellent properties are comparable to or even better than those of natural muscles, making the polyprotein-based hydrogels represent a new type of muscle-mimetic biomaterial. Significantly, the prominent biocompatibility of the designed biomaterials further enables them to hold potential applications in the biomedical field and tissue engineering.
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Affiliation(s)
- Linlu Zhao
- The First Affiliated Hospital of Hainan Medical University, Key Laboratory of Emergency and Trauma, Ministry of Education, College of Emergency and Trauma, Hainan Medical University, Haikou 571199, China.,State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Xin Zhang
- Institute for Interdisciplinary Biomass Functional Materials Studies, Jilin Engineering Normal University, No. 3050, Kaixuan Road, Changchun 130052, China
| | - Quan Luo
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Chunxi Hou
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Jiayun Xu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China.,State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Junqiu Liu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China.,State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
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17
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Reggiani C. Caffeine as a tool to investigate sarcoplasmic reticulum and intracellular calcium dynamics in human skeletal muscles. J Muscle Res Cell Motil 2020; 42:281-289. [PMID: 32034582 DOI: 10.1007/s10974-020-09574-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/30/2020] [Indexed: 12/23/2022]
Abstract
Caffeine is worldwide used for its power to increase cognitive and physical performance. The ergogenic effects of caffeine, however, do not depend on a direct action on muscles. Actually, the actions of caffeine on skeletal muscles, take place at millimolar concentrations which are far above the micromolar level reached after a regular consumption of coffee or similar drinks, and close to a lethal concentration. At millimolar concentrations caffeine exerts a powerful effect on sarcoplasmic reticulum (SR) activating the release of calcium via ryanodine receptors and, possibly, inhibiting calcium reuptake. For this reason caffeine has become a valuable tool for studying SR function and for diagnostics of SR related muscle disorders. This review aims to briefly describe the effects and the mechanism of action of caffeine on sarcoplasmic reticulum and to focus on its use to study intracellular calcium dynamics in human muscle fibers in physiological and pathological conditions.
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Affiliation(s)
- Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Via Marzolo 3, 35131, Padua, Italy. .,ZRS-Science and Research Center, Koper, Slovenia.
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18
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Anderson CV, Roberts TJ. The need for speed: functional specializations of locomotor and feeding muscles in Anolis lizards. ACTA ACUST UNITED AC 2020; 223:jeb.213397. [PMID: 31862851 DOI: 10.1242/jeb.213397] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/16/2019] [Indexed: 12/21/2022]
Abstract
Muscles often perform diverse mechanical roles within an organism. Tuning of contractile properties may therefore provide an opportunity for muscles to better perform their different roles and impact their associated whole-organism performance. Here, we examined the muscle contractile physiology of a jaw and a leg muscle in five Anolis species to determine whether consistent physiological differences are found in these muscles. We found that these jaw and leg muscles exhibited consistent patterns of variation across species, which may be related to the functional use of each muscle. In particular, we found that each muscle had differentially increased different measures of muscle speed. Although the jaw muscles had faster peak contractile velocities than the leg muscles, the leg muscles had faster twitch times and faster contractile velocities under intermediate loads. We also found that the jaw muscles exerted higher specific tensions and had a greater curvature to their force-velocity relationship. The consistent patterns across five species suggest that these jaw and leg muscles have specialized in different ways. Examination of these contractile property variations may help illuminate important features relating to performing their individual functional roles.
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Affiliation(s)
- Christopher V Anderson
- Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD 57069, USA
| | - Thomas J Roberts
- Department of Ecology and Evolutionary Biology, Brown University, Box G-B205, Providence, RI 02912, USA
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19
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Watanabe D, Hatakeyama K, Ikegami R, Eshima H, Yagishita K, Poole DC, Kano Y. Sex differences in mitochondrial Ca 2+ handling in mouse fast-twitch skeletal muscle in vivo. J Appl Physiol (1985) 2020; 128:241-251. [PMID: 31917626 DOI: 10.1152/japplphysiol.00230.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We investigated sex differences in mitochondrial Ca2+ handling properties in mouse fast-twitch skeletal muscle. Changes in cytoplasmic Ca2+ concentration ([Ca2+]cyto) were measured in vivo using tibialis anterior muscles from male and female mice. The muscles were exposed to increasing concentrations of cyclopiazonic acid [CPA; sarcoplasmic reticulum (SR) Ca2+-ATPase inhibitor] (from 10 to 30 to 50 μM at 10 min intervals). Thirty minutes after treatment, [Ca2+]cyto was increased by 31.6 ± 2.0% and 13.5 ± 4.5% of initial [Ca2+]cyto in male and female muscles, respectively, and there was a significant difference between sexes. However, muscle preincubation for 5 min with 10 μM carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (an inhibitor of mitochondria Ca2+ uptake) eradicated this difference between sexes with respect to the CPA-induced [Ca2+]cyto increase. Both intermyofibrillar mitochondrial number and volume, assessed in longitudinal fiber sections, were higher in females compared with males (mitochondria number: 13.1 ± 1.0 in males vs. 19.9 ± 2.3 in females; mitochondrial volume: 0.034 ± 0.004 μm3/μm3 fiber volume in males vs. 0.066 ± 0.008 μm3/μm3 fiber volume in females, both P < 0.05). There were no sex differences in the content of SR Ca2+-ATPase, mitochondrial Ca2+ uniporter, mitofusin (Mfn) 1, or Mfn2. These results suggest that 1) mitochondrial Ca2+ uptake ability is greater in female than male myocytes, and 2) this superior Ca2+ uptake ability of female myocytes is due, partly, to the higher intermyofibrillar mitochondrial content but not to the expression of mitochondrial proteins related to mitochondrial Ca2+ uptake.NEW & NOTEWORTHY This investigation presents evidence that female versus male fast-twitch muscle exhibits a greater mitochondrial calcium ion uptake capability that is partly conferred by the higher intermyofibrillar mitochondrial volume density.
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Affiliation(s)
- Daiki Watanabe
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan.,Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Koji Hatakeyama
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan
| | - Ryo Ikegami
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan
| | - Hiroaki Eshima
- Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Kazuyoshi Yagishita
- Clinical Center for Sports Medicine and Sports Dentistry, Hyperbaric Medical Center/Sports Medicine Clinical Center, Medical Hospital of Tokyo Medical and Dental University, Tokyo, Japan
| | - David C Poole
- Departments of Anatomy & Physiology and of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Bioscience and Technology Program, Department of Engineering Sciences, University of Electro-Communications, Tokyo, Japan.,Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Tokyo, Japan
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20
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Chen X, Chen Y, Huang C, Dong Q, Roper C, Tanguay RL, Zhu Y, Zhang Y. Neurodevelopmental toxicity assessments of alkyl phenanthrene and Dechlorane Plus co-exposure in zebrafish. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:762-769. [PMID: 31154201 DOI: 10.1016/j.ecoenv.2019.05.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 05/18/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
Alkyl phenanthrene (A-Phen) and Dechlorane Plus (DP) are ubiquitous environmental pollutants that widely co-exist in the environment. It has been established that both A-Phen and DP elicit neurotoxicity, but the potential interactive toxicity of these contaminants is not well-known. To determine whether a mixture of A-Phen and DP would exhibit interactive effects on neurodevelopment, we co-exposed 3-methylphenanthrene (3-MP), a representative of A-Phen, with DP. Our results illustrated that exposure to 5 or 20 μg/L 3-MP alone or in combination with 60 μg/L DP caused neurobehavioral anomalies in zebrafish. In accordance with the behavioral deficits, 3-MP alone or co-exposed with DP significantly decreased axonal growth of secondary motoneurons, altered intracellular Ca2+ homeostasis and induced cell apoptosis in the muscle of zebrafish. Additionally, 3-MP alone or co-exposed with DP significantly increased reactive oxygen species (ROS) and the mRNA levels of apoptosis-related genes. These findings indicate that 3-MP alone or co-exposed with DP induces neurobehavioral deficits through the combined effects on neuronal connectivity and muscle function. Chemical analysis revealed significant increases in 3-MP and DP bioaccumulation in zebrafish co-exposed with 3-MP and DP. Elevated bioaccumulation resulting from mixture exposure may represent a significant contribution of the synergistic effects observed in combined chemical exposure.
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Affiliation(s)
- Xiangping Chen
- State Key Laboratory of Marine Environmental Science of China (Xiamen University), College of the Environment and Ecology, Xiamen University, Xiamen, 361102, PR China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yuanhong Chen
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou, 325035, PR China
| | - Changjiang Huang
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou, 325035, PR China
| | - Qiaoxiang Dong
- Institute of Environmental Safety and Human Health, Wenzhou Medical University, Wenzhou, 325035, PR China; The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, 325035, PR China
| | - Courtney Roper
- Environmental and Molecular Toxicology, The Sinnhuber Aquatic Research Laboratory and the Environmental Health Sciences Center, Oregon State University, Corvallis, OR, 97333, USA
| | - Rorbet L Tanguay
- Environmental and Molecular Toxicology, The Sinnhuber Aquatic Research Laboratory and the Environmental Health Sciences Center, Oregon State University, Corvallis, OR, 97333, USA
| | - Yaxian Zhu
- Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
| | - Yong Zhang
- State Key Laboratory of Marine Environmental Science of China (Xiamen University), College of the Environment and Ecology, Xiamen University, Xiamen, 361102, PR China.
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21
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Katz MG, Fargnoli AS, Gubara SM, Chepurko E, Bridges CR, Hajjar RJ. Surgical and physiological challenges in the development of left and right heart failure in rat models. Heart Fail Rev 2019; 24:759-777. [PMID: 30903356 PMCID: PMC6698228 DOI: 10.1007/s10741-019-09783-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rodent surgical animal models of heart failure (HF) are critically important for understanding the proof of principle of the cellular alterations underlying the development of the disease as well as evaluating therapeutics. Robust, reproducible rodent models are a prerequisite to the development of pharmacological and molecular strategies for the treatment of HF in patients. Due to the absence of standardized guidelines regarding surgical technique and clear criteria for HF progression in rats, objectivity is compromised. Scientific publications in rats rarely fully disclose the actual surgical details, and technical and physiological challenges. This lack of reporting is one of the main reasons that the outcomes specified in similar studies are highly variable and associated with unnecessary loss of animals, compromising scientific assessment. This review details rat circulatory and coronary arteries anatomy, the surgical details of rat models that recreate the HF phenotype of myocardial infarction, ischemia/reperfusion, left and right ventricular pressure, and volume overload states, and summarizes the technical and physiological challenges of creating HF. The purpose of this article is to help investigators understand the underlying issues of current HF models in order to reduce variable results and ensure successful, reproducible models of HF.
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Affiliation(s)
- Michael G Katz
- Cardiovascular Research Center, Department of Cardiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., Box 1030, New York, NY, 10029-6574, USA.
| | - Anthony S Fargnoli
- Cardiovascular Research Center, Department of Cardiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., Box 1030, New York, NY, 10029-6574, USA
| | - Sarah M Gubara
- Cardiovascular Research Center, Department of Cardiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., Box 1030, New York, NY, 10029-6574, USA
| | - Elena Chepurko
- Cardiovascular Research Center, Department of Cardiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., Box 1030, New York, NY, 10029-6574, USA
| | - Charles R Bridges
- Cardiovascular Research Center, Department of Cardiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., Box 1030, New York, NY, 10029-6574, USA
| | - Roger J Hajjar
- Cardiovascular Research Center, Department of Cardiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., Box 1030, New York, NY, 10029-6574, USA
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22
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Christiansen D, MacInnis MJ, Zacharewicz E, Xu H, Frankish BP, Murphy RM. A fast, reliable and sample-sparing method to identify fibre types of single muscle fibres. Sci Rep 2019; 9:6473. [PMID: 31019216 PMCID: PMC6482153 DOI: 10.1038/s41598-019-42168-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/08/2019] [Indexed: 11/30/2022] Open
Abstract
Many skeletal muscle proteins are present in a cell-specific or fibre-type dependent manner. Stimuli such as exercise, aging, and disease have been reported to result in fibre-specific responses in protein abundances. Thus, fibre-type-specific determination of the content of specific proteins provides enhanced mechanistic understanding of muscle physiology and biochemistry compared with typically performed whole-muscle homogenate analyses. This analysis, however, is laborious and typically not performed. We present a novel dot blotting method for easy and rapid determination of skeletal muscle fibre type based on myosin heavy chain (MHC) isoform presence. Requiring only small amounts of starting muscle tissue (i.e., 2–10 mg wet weight), muscle fibre type is determined in one-tenth of a 1–3-mm fibre segment, with the remainder of each segment pooled with fibre segments of the same type (I or II) for subsequent protein quantification by western blotting. This method, which we validated using standard western blotting, is much simpler and cheaper than previous methods and is adaptable for laboratories routinely performing biochemical analyses. Use of dot blotting for fibre typing will facilitate investigations of fibre-specific responses to diverse stimuli, which will advance our understanding of skeletal muscle physiology and biochemistry.
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Affiliation(s)
- Danny Christiansen
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.,Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Martin J MacInnis
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.,Faculty of Kinesiology, University of Calgary, Calgary, Canada
| | - Evelyn Zacharewicz
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Hongyang Xu
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Barnaby P Frankish
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.
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23
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Hostrup M, Narkowicz CK, Habib S, Nichols DS, Jacobson GA. Beta
2
‐adrenergic ligand racemic formoterol exhibits enantioselective disposition in blood and skeletal muscle of humans, and elicits myocellular PKA signaling at therapeutic inhaled doses. Drug Test Anal 2019; 11:1048-1056. [DOI: 10.1002/dta.2580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and SportsUniversity of Copenhagen Copenhagen Denmark
| | | | - Sajad Habib
- Section of Integrative Physiology, Department of Nutrition, Exercise and SportsUniversity of Copenhagen Copenhagen Denmark
| | - David S. Nichols
- Central Science LaboratoryUniversity of Tasmania Hobart Australia
| | - Glenn A. Jacobson
- Discipline of Pharmacy, School of MedicineUniversity of Tasmania Hobart Australia
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24
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Christiansen D. Molecular stressors underlying exercise training-induced improvements in K + regulation during exercise and Na + ,K + -ATPase adaptation in human skeletal muscle. Acta Physiol (Oxf) 2019; 225:e13196. [PMID: 30288889 DOI: 10.1111/apha.13196] [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: 07/25/2018] [Revised: 09/12/2018] [Accepted: 09/28/2018] [Indexed: 12/28/2022]
Abstract
Despite substantial progress made towards a better understanding of the importance of skeletal muscle K+ regulation for human physical function and its association with several disease states (eg type-II diabetes and hypertension), the molecular basis underpinning adaptations in K+ regulation to various stimuli, including exercise training, remains inadequately explored in humans. In this review, the molecular mechanisms essential for enhancing skeletal muscle K+ regulation and its key determinants, including Na+ ,K+ -ATPase function and expression, by exercise training are examined. Special attention is paid to the following molecular stressors and signaling proteins: oxygenation, redox balance, hypoxia, reactive oxygen species, antioxidant function, Na+ ,K+ , and Ca2+ concentrations, anaerobic ATP turnover, AMPK, lactate, and mRNA expression. On this basis, an update on the effects of different types of exercise training on K+ regulation in humans is provided, focusing on recent discoveries about the muscle fibre-type-dependent regulation of Na+ ,K+ -ATPase-isoform expression. Furthermore, with special emphasis on blood-flow-restricted exercise as an exemplary model to modulate the key molecular mechanisms identified, it is discussed how training interventions may be designed to maximize improvements in K+ regulation in humans. The novel insights gained from this review may help us to better understand how exercise training and other strategies, such as pharmacological interventions, may be best designed to enhance K+ regulation and thus the physical function in humans.
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Affiliation(s)
- Danny Christiansen
- Department of Nutrition, Exercise and Sports (NEXS) University of Copenhagen Copenhagen Denmark
- Institute for Health and Sport (IHES) Victoria University Melbourne Victoria Australia
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25
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Lamb GD, Stephenson DG. Measurement of force and calcium release using mechanically skinned fibers from mammalian skeletal muscle. J Appl Physiol (1985) 2018; 125:1105-1127. [DOI: 10.1152/japplphysiol.00445.2018] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The mechanically skinned (or “peeled”) skeletal muscle fiber technique is a highly versatile procedure that allows controlled examination of each of the steps in the excitation-contraction (EC)-coupling sequence in skeletal muscle fibers, starting with excitation/depolarization of the transverse tubular (T)-system through to Ca2+ release from sarcoplasmic reticulum (SR) and finally force development by the contractile apparatus. It can also show the overall response of the whole EC-coupling sequence together, such as in twitch and tetanic force responses. A major advantage over intact muscle fiber preparations is that it is possible to set and rapidly manipulate the “intracellular” conditions, allowing examination of the effects of key variables (e.g., intracellular pH, ATP levels, redox state, etc.) on each individual step in EC coupling. This Cores of Reproducibility in Physiology (CORP) article describes the rationale, procedures, and experimental details of the various ways in which the mechanically skinned fiber technique is used in our laboratory to examine the physiological mechanisms controlling Ca2+ release and contraction in skeletal muscle fibers and the aberrations and dysfunction occurring with exercise and disease.
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Affiliation(s)
- Graham D. Lamb
- Department of Physiology, Anatomy, and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - D. George Stephenson
- Department of Physiology, Anatomy, and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
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26
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Berg OK, Kwon OS, Hureau TJ, Clifton HL, Thurston T, Le Fur Y, Jeong EK, Amann M, Richardson RS, Trinity JD, Wang E, Layec G. Maximal strength training increases muscle force generating capacity and the anaerobic ATP synthesis flux without altering the cost of contraction in elderly. Exp Gerontol 2018; 111:154-161. [PMID: 30031838 DOI: 10.1016/j.exger.2018.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/09/2018] [Accepted: 07/18/2018] [Indexed: 01/09/2023]
Abstract
Aging is associated with a progressive decline in skeletal muscle function, then leading to impaired exercise tolerance. Maximal strength training (MST) appears to be a practical and effective intervention to increase both exercise capacity and efficiency. However, the underlying physiological mechanisms responsible for these functional improvements are still unclear. Accordingly, the purpose of this study was to examine the intramuscular and metabolic adaptations induced by 8 weeks of knee-extension MST in the quadriceps of 10 older individuals (75 ± 9 yrs) by employing a combination of molecular, magnetic resonance 1H-imaging and 31P-spectroscopy, muscle biopsies, motor nerve stimulation, and indirect calorimetry techniques. Dynamic and isometric muscle strength were both significantly increased by MST. The greater torque-time integral during sustained isometric maximal contraction post-MST (P = 0.002) was associated with increased rates of ATP synthesis from anaerobic glycolysis (PRE: 10 ± 7 mM·min-1; POST: 14 ± 7 mM·min-1, P = 0.02) and creatine kinase reaction (PRE: 31 ± 10 mM·min-1; POST: 41 ± 10 mM·min-1, P = 0.006) such that the ATP cost of contraction was not significantly altered. Expression of fast myosin heavy chain, quadriceps muscle volume, and submaximal cycling net efficiency were also increased with MST (P = 0.005; P = 0.03 and P = 0.03, respectively). Overall, MST induced a shift toward a more glycolytic muscle phenotype allowing for greater muscle force production during sustained maximal contraction. Consequently, some of the MST-induced improvements in exercise tolerance might stem from a greater anaerobic capacity to generate ATP, while the improvement in exercise efficiency appears to be independent from an alteration in the ATP cost of contraction.
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Affiliation(s)
- Ole Kristian Berg
- Faculty of Health and Social Sciences, Molde University College, Molde, Norway.
| | - Oh Sung Kwon
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA
| | - Thomas J Hureau
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA
| | - Heather L Clifton
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA
| | - Taylor Thurston
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Yann Le Fur
- CRMBM, Aix-Marseille Universite, CNRS 7339, Marseille, France
| | - Eun-Kee Jeong
- Department of Radiology, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA
| | - Markus Amann
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA; Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Russel S Richardson
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Joel D Trinity
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Eivind Wang
- Faculty of Health and Social Sciences, Molde University College, Molde, Norway; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Department of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Research and Development, St. Olav's University Hospital, Trondheim, Norway
| | - Gwenael Layec
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
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27
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Mosole S, Zampieri S, Furlan S, Carraro U, Löefler S, Kern H, Volpe P, Nori A. Effects of Electrical Stimulation on Skeletal Muscle of Old Sedentary People. Gerontol Geriatr Med 2018; 4:2333721418768998. [PMID: 29662923 PMCID: PMC5896842 DOI: 10.1177/2333721418768998] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/25/2018] [Accepted: 02/08/2018] [Indexed: 01/10/2023] Open
Abstract
Physical activity plays an important role in preventing muscle atrophy and chronic diseases in adults and in the elderly. Calcium (Ca2+) cycling and activation of specific molecular pathways are essential in contraction-induced muscle adaptation. This study attains human muscle sections and total homogenates prepared from biopsies obtained before (control) and after 9 weeks of training by electrical stimulation (ES) on a group of volunteers. The aim of the study was to investigate about the molecular mechanisms that support functional muscle improvement by ES. Evidences of kinase/phosphatase pathways activation after ES were obtained. Moreover, expression of Sarcalumenin, Calsequestrin and sarco/endoplasmic reticulum Ca2+-ATPase (Serca) isoforms was regulated by training. In conclusion, this work shows that neuromuscular ES applied to vastus lateralis muscle of sedentary seniors combines fiber remodeling with activation of Ca2+-Calmodulin molecular pathways and modulation of key Ca2+-handling proteins.
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Affiliation(s)
- Simone Mosole
- University of Padova, Italy.,Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Sandra Zampieri
- University of Padova, Italy.,Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Sandra Furlan
- Institute of Neuroscience Consiglio Nazionale delle Ricerche, Padova, Italy
| | - Ugo Carraro
- IRRCS Fondazione Ospedale San Camillo, Venice, Italy
| | - Stefan Löefler
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Helmut Kern
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria.,Institute of Physical Medicine and Rehabilitation, St. Pölten, Austria
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28
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Tobias IS, Lazauskas KK, Arevalo JA, Bagley JR, Brown LE, Galpin AJ. Fiber type-specific analysis of AMPK isoforms in human skeletal muscle: advancement in methods via capillary nanoimmunoassay. J Appl Physiol (1985) 2018; 124:840-849. [DOI: 10.1152/japplphysiol.00894.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human skeletal muscle is a heterogeneous mixture of multiple fiber types (FT). Unfortunately, present methods for FT-specific study are constrained by limits of protein detection in single-fiber samples. These limitations beget compensatory resource-intensive procedures, ultimately dissuading investigators from pursuing FT-specific research. Additionally, previous studies neglected hybrid FT, confining their analyses to only pure FT. Here we present novel methods of protein detection across a wider spectrum of human skeletal muscle FT using fully automated capillary nanoimmunoassay (CNIA) technology. CNIA allowed a ~20-fold-lower limit of 5′-AMP-activated protein kinase (AMPK) detection compared with Western blotting. We then performed FT-specific assessment of AMPK expression as a proof of concept. Individual human muscle fibers were mechanically isolated, dissolved, and myosin heavy chain (MHC) fiber typed via SDS-PAGE. Single-fiber samples were combined in pairs and grouped into MHC I, MHC I/IIa, MHC IIa, and MHC IIa/IIx for expression analysis of AMPK isoforms α1, α2, β1, β2, γ2, and γ3 with a tubulin loading control. Significant FT-specific differences were found for α2 (1.7-fold higher in MHC IIa and MHC IIa/IIx vs. others), γ2 (2.5-fold higher in MHC IIa vs. others), and γ3 (2-fold higher in MHC IIa and 4-fold higher in MHC IIa/IIx vs. others). Development of a protocol that combines the efficient and sensitive CNIA technology with comprehensive SDS-PAGE fiber typing marks an important advancement in FT-specific research because it allows more precise study of the molecular mechanisms governing metabolism, adaptation, and regulation in human muscle. NEW & NOTEWORTHY We demonstrate the viability of applying capillary nanoimmunoassay technology to the study of fiber type-specific protein analysis in human muscle fibers. This novel technique enables a ~20-fold-lower limit of protein detection compared with traditional Western blotting methods. Combined with SDS-PAGE methods of fiber typing, we apply this technique to compare 5′-AMP-activated protein kinase isoform expression in myosin heavy chain (MHC) I, MHC I/IIa, MHC IIa, and MHC IIa/IIx fiber types.
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Affiliation(s)
- Irene S. Tobias
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Kara K. Lazauskas
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Jose A. Arevalo
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - James R. Bagley
- Muscle Physiology Laboratory, Department of Kinesiology, San Francisco State University, San Francisco, California
| | - Lee E. Brown
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Andrew J. Galpin
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
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29
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Franzini-Armstrong C. The relationship between form and function throughout the history of excitation-contraction coupling. J Gen Physiol 2018; 150:189-210. [PMID: 29317466 PMCID: PMC5806676 DOI: 10.1085/jgp.201711889] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Franzini-Armstrong reviews the development of the excitation–contraction coupling field over time. The concept of excitation–contraction coupling is almost as old as Journal of General Physiology. It was understood as early as the 1940s that a series of stereotyped events is responsible for the rapid contraction response of muscle fibers to an initial electrical event at the surface. These early developments, now lost in what seems to be the far past for most young investigators, have provided an endless source of experimental approaches. In this Milestone in Physiology, I describe in detail the experiments and concepts that introduced and established the field of excitation–contraction coupling in skeletal muscle. More recent advances are presented in an abbreviated form, as readers are likely to be familiar with recent work in the field.
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Affiliation(s)
- Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA
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30
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Hostrup M, Onslev J, Jacobson GA, Wilson R, Bangsbo J. Chronic β 2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men. J Physiol 2017; 596:231-252. [PMID: 28983994 DOI: 10.1113/jp274970] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/26/2017] [Indexed: 12/26/2022] Open
Abstract
KEY POINTS While several studies have investigated the effects of exercise training in human skeletal muscle and the chronic effect of β2 -agonist treatment in rodent muscle, their effects on muscle proteome signature with related functional measures in humans are still incompletely understood. Herein we show that daily β2 -agonist treatment attenuates training-induced enhancements in exercise performance and maximal oxygen consumption, and alters muscle proteome signature and phenotype in trained young men. Daily β2 -agonist treatment abolished several of the training-induced enhancements in muscle oxidative capacity and caused a repression of muscle metabolic pathways; furthermore, β2 -agonist treatment induced a slow-to-fast twitch muscle phenotype transition. The present study indicates that chronic β2 -agonist treatment confounds the positive effect of high intensity training on exercise performance and oxidative capacity, which is of interest for the large proportion of persons using inhaled β2 -agonists on a daily basis, including athletes. ABSTRACT Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β2 -agonists are frequently used to counteract exercise-induced bronchoconstriction, but the effects β2 -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomly assigned 21 trained men to 4 weeks of high intensity training with (HIT+β2 A) or without (HIT) daily inhalation of β2 -agonist (terbutaline, 4 mg dose-1 ). Of 486 proteins identified by mass-spectrometry proteomics of muscle biopsies sampled before and after the intervention, 32 and 85 were changing (false discovery rate (FDR) ≤5%) with the intervention in HIT and HIT+β2 A, respectively. Proteome signature changes were different in HIT and HIT+β2 A (P = 0.005), wherein β2 -agonist caused a repression of 25 proteins in HIT+β2 A compared to HIT, and an upregulation of 7 proteins compared to HIT. β2 -Agonist repressed or even downregulated training-induced enrichment of pathways related to oxidative phosphorylation and glycogen metabolism, but upregulated pathways related to histone trimethylation and the nucleosome. Muscle contractile phenotype changed differently in HIT and HIT+β2 A (P ≤ 0.001), with a fast-to-slow twitch transition in HIT and a slow-to-fast twitch transition in HIT+β2 A. β2 -Agonist attenuated training-induced enhancements in maximal oxygen consumption (P ≤ 0.01) and exercise performance (6.1 vs. 11.6%, P ≤ 0.05) in HIT+β2 A compared to HIT. These findings indicate that daily β2 -agonist treatment attenuates the beneficial effects of high intensity training on exercise performance and oxidative capacity, and causes remodelling of muscle proteome signature towards a fast-twitch phenotype.
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Affiliation(s)
- Morten Hostrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Johan Onslev
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Glenn A Jacobson
- Division of Pharmacy, School of Medicine, University of Tasmania, Hobart, Australia
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, Australia
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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31
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WHITFIELD JAMIE, GAMU DANIEL, HEIGENHAUSER GEORGEJF, VAN LOON LUCJC, SPRIET LAWRENCEL, TUPLING ARUSSELL, HOLLOWAY GRAHAMP. Beetroot Juice Increases Human Muscle Force without Changing Ca2+-Handling Proteins. Med Sci Sports Exerc 2017; 49:2016-2024. [DOI: 10.1249/mss.0000000000001321] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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32
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Bjorksten AR, Gillies RL, Hockey BM, Du Sart D. Sequencing of genes involved in the movement of calcium across human skeletal muscle sarcoplasmic reticulum: continuing the search for genes associated with malignant hyperthermia. Anaesth Intensive Care 2017; 44:762-768. [PMID: 27832566 DOI: 10.1177/0310057x1604400625] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The genetic basis of malignant hyperthermia (MH) is not fully characterised and likely involves more than just the currently classified mutations in the gene encoding the skeletal muscle ryanodine receptor (RYR1) and the gene encoding the α1 subunit of the dihydropyridine receptor (CACNA1S). In this paper we sequence other genes involved in calcium trafficking within skeletal muscle in patients with positive in vitro contracture tests, searching for alternative genes associated with MH. We identified four rare variants in four different genes (CACNB1, CASQ1, SERCA1 and CASQ2) encoding proteins involved in calcium handling in skeletal muscle in a cohort of 30 Australian MH susceptible probands in whom prior complete sequencing of RYR1 and CACNA1S had yielded no rare variants. These four variants have very low minor allele frequencies and while it is tempting to speculate that they have a role in MH, they remain at present variants of unknown significance. Nevertheless they provide the basis for a new set of functional studies, which may indeed identify novel players in MH.
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Affiliation(s)
- A R Bjorksten
- Senior Scientist, Malignant Hyperthermia Diagnostic Unit, Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Anaesthesia, Perioperative and Pain Medicine Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Victorian Clinical Genetics Service Molecular Genetics Laboratory, Murdoch Children's Research Institut
| | - R L Gillies
- Head, Malignant Hyperthermia Diagnostic Unit, Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Anaesthesia, Perioperative and Pain Medicine Unit, University of Melbourne, Victoria
| | - B M Hockey
- Malignant Hyperthermia Diagnostic Unit, Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Consultant Anaesthetist, Anaesthesia, Perioperative and Pain Medicine Unit, University of Melbourne, Victoria
| | - D Du Sart
- Research Affiliate/Head, Victorian Clinical Genetics Service Molecular Genetics Laboratory, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria
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33
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Begue G, Raue U, Jemiolo B, Trappe S. DNA methylation assessment from human slow- and fast-twitch skeletal muscle fibers. J Appl Physiol (1985) 2017; 122:952-967. [PMID: 28057818 DOI: 10.1152/japplphysiol.00867.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/07/2016] [Accepted: 12/30/2016] [Indexed: 11/22/2022] Open
Abstract
A new application of the reduced representation bisulfite sequencing method was developed using low-DNA input to investigate the epigenetic profile of human slow- and fast-twitch skeletal muscle fibers. Successful library construction was completed with as little as 15 ng of DNA, and high-quality sequencing data were obtained with 32 ng of DNA. Analysis identified 143,160 differentially methylated CpG sites across 14,046 genes. In both fiber types, selected genes predominantly expressed in slow or fast fibers were hypomethylated, which was supported by the RNA-sequencing analysis. These are the first fiber type-specific methylation data from human skeletal muscle and provide a unique platform for future research.NEW & NOTEWORTHY This study validates a low-DNA input reduced representation bisulfite sequencing method for human muscle biopsy samples to investigate the methylation patterns at a fiber type-specific level. These are the first fiber type-specific methylation data reported from human skeletal muscle and thus provide initial insight into basal state differences in myosin heavy chain I and IIa muscle fibers among young, healthy men.
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Affiliation(s)
- Gwénaëlle Begue
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Ulrika Raue
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Bozena Jemiolo
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Scott Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana
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34
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Lamboley CR, Wyckelsma VL, Perry BD, McKenna MJ, Lamb GD. Effect of 23-day muscle disuse on sarcoplasmic reticulum Ca2+ properties and contractility in human type I and type II skeletal muscle fibers. J Appl Physiol (1985) 2016; 121:483-92. [DOI: 10.1152/japplphysiol.00337.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/28/2016] [Indexed: 11/22/2022] Open
Abstract
Inactivity negatively impacts on skeletal muscle function mainly through muscle atrophy. However, recent evidence suggests that the quality of individual muscle fibers is also altered. This study examined the effects of 23 days of unilateral lower limb suspension (ULLS) on specific force and sarcoplasmic reticulum (SR) Ca2+ content in individual skinned muscle fibers. Muscle biopsies of the vastus lateralis were taken from six young healthy adults prior to and following ULLS. After disuse, the endogenous SR Ca2+ content was ∼8% lower in type I fibers and maximal SR Ca2+ capacity was lower in both type I and type II fibers (−11 and −5%, respectively). The specific force, measured in single skinned fibers from three subjects, decreased significantly after ULLS in type II fibers (−23%) but not in type I fibers (−9%). Western blot analyses showed no significant change in the amounts of myosin heavy chain (MHC) I and MHC IIa following the disuse, whereas the amounts of sarco(endo)plasmic reticulum Ca2+-ATPase 1 (SERCA1) and calsequestrin increased by ∼120 and ∼20%, respectively, and the amount of troponin I decreased by ∼21%. These findings suggest that the decline in force and power occurring with muscle disuse is likely to be exacerbated in part by reductions in maximum specific force in type II fibers, and in the amount of releasable SR Ca2+ in both fiber types, the latter not being attributable to a reduced calsequestrin level. Furthermore, the ∼3-wk disuse in human elicits change in SR properties, in particular a more than twofold upregulation in SERCA1 density, before any fiber-type shift.
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Affiliation(s)
- C. R. Lamboley
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - V. L. Wyckelsma
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia; and
| | - B. D. Perry
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- Renal Division, Department of Medicine, Emory University, Atlanta, Georgia
| | - M. J. McKenna
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - G. D. Lamb
- School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
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Fajardo VA, Smith IC, Bombardier E, Chambers PJ, Quadrilatero J, Tupling AR. Diaphragm assessment in mice overexpressing phospholamban in slow-twitch type I muscle fibers. Brain Behav 2016; 6:e00470. [PMID: 27134770 PMCID: PMC4842933 DOI: 10.1002/brb3.470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/08/2016] [Accepted: 03/11/2016] [Indexed: 12/30/2022] Open
Abstract
AIMS Phospholamban (PLN) and sarcolipin (SLN) are small inhibitory proteins that regulate the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pump. Previous work from our laboratory revealed that in the soleus and gluteus minimus muscles of mice overexpressing PLN (Pln (OE)), SERCA function was impaired, dynamin 2 (3-5 fold) and SLN (7-9 fold) were upregulated, and features of human centronuclear myopathy (CNM) were observed. Here, we performed structural and functional experiments to evaluate whether the diaphragm muscles of the Pln (OE) mouse would exhibit CNM pathology and muscle weakness. METHODS Diaphragm muscles from Pln (OE) and WT mice were subjected to histological/histochemical/immunofluorescent staining, Ca(2+)-ATPase and Ca(2+) uptake assays, Western blotting, and in vitro electrical stimulation. RESULTS Our results demonstrate that PLN overexpression reduced SERCA's apparent affinity for Ca(2+) but did not reduce maximal SERCA activity or rates of Ca(2+) uptake. SLN was upregulated 2.5-fold, whereas no changes in dynamin 2 expression were found. With respect to CNM, we did not observe type I fiber predominance, central nuclei, or central aggregation of oxidative activity in diaphragm, although type I fiber hypotrophy was present. Furthermore, in vitro contractility assessment of Pln (OE) diaphragm strips revealed no reductions in force-generating capacity, maximal rates of relaxation or force development, but did indicate that ½ relaxation time was prolonged. CONCLUSIONS Therefore, the effects of PLN overexpression on skeletal muscle phenotype differ between diaphragm and the postural soleus and gluteus minimus muscles. Our findings here point to differences in SLN expression and type I fiber distribution as potential contributing factors.
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Affiliation(s)
| | - Ian Curtis Smith
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Eric Bombardier
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Paige J Chambers
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Joe Quadrilatero
- Department of Kinesiology University of Waterloo Waterloo ON Canada
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Abstract
Limb-girdle muscular dystrophy type 2A (LGMD2A) is a form of muscular dystrophy caused by
mutations in calpain 3 (CAPN3). Several studies have implicated Ca2+
dysregulation as an underlying event in several muscular dystrophies, including LGMD2A. In
this study we used mouse and human myotube cultures, and muscle biopsies in order to
determine whether dysfunction of sarco/endoplasmatic Ca2+-ATPase (SERCA) is
involved in the pathology of this disease. In CAPN3-deficient myotubes, we found decreased
levels of SERCA 1 and 2 proteins, while mRNA levels remained comparable with control
myotubes. Also, we found a significant reduction in SERCA function that resulted in
impairment of Ca2+ homeostasis, and elevated basal intracellular
[Ca2+] in human myotubes. Furthermore, small Ankyrin 1 (sAnk1), a
SERCA1-binding protein that is involved in sarcoplasmic reticulum integrity, was also
diminished in CAPN3-deficient fibres. Interestingly, SERCA2 protein was patently reduced
in muscles from LGMD2A patients, while it was normally expressed in other forms of
muscular dystrophy. Thus, analysis of SERCA2 expression may prove useful for diagnostic
purposes as a potential indicator of CAPN3 deficiency in muscle biopsies. Altogether, our
results indicate that CAPN3 deficiency leads to degradation of SERCA proteins and
Ca2+ dysregulation in the skeletal muscle. While further studies are needed
in order to elucidate the specific contribution of SERCA towards muscle degeneration in
LGMD2A, this study constitutes a reasonable foundation for the development of therapeutic
approaches targeting SERCA1, SERCA2 or sAnk1.
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Lamboley CR, Wyckelsma VL, McKenna MJ, Murphy RM, Lamb GD. Ca(2+) leakage out of the sarcoplasmic reticulum is increased in type I skeletal muscle fibres in aged humans. J Physiol 2015; 594:469-81. [PMID: 26574292 DOI: 10.1113/jp271382] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/11/2015] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS The amount of Ca(2+) stored in the sarcoplasmic reticulum (SR) of muscle fibres is decreased in aged individuals, and an important question is whether this results from increased Ca(2+) leakage out through the Ca(2+) release channels (ryanodine receptors; RyRs). The present study examined the effects of blocking the RyRs with Mg(2+), or applying a strong reducing treatment, on net Ca(2+) accumulation by the SR in skinned muscle fibres from Old (∼70 years) and Young (∼24 years) adults. Raising cytoplasmic [Mg(2+)] and reducing treatment increased net SR Ca(2+) accumulation in type I fibres of Old subjects relative to that in Young. The densities of RyRs and dihydropyridine receptors were not significantly changed in the muscle of Old subjects. These findings indicate that oxidative modification of the RyRs causes increased Ca(2+) leakage from the SR in muscle fibres in Old subjects, which probably deleteriously affects normal muscle function both directly and indirectly. ABSTRACT The present study examined whether the lower Ca(2+) storage levels in the sarcoplasmic reticulum (SR) in vastus lateralis muscle fibres in Old (70 ± 4 years) relative to Young (24 ± 4 years) human subjects is the result of increased leakage of Ca(2+) out of the SR through the Ca(2+) release channels/ryanodine receptors (RyRs) and due to oxidative modification of the RyRs. SR Ca(2+) accumulation in mechanically skinned muscle fibres was examined in the presence of 1, 3 or 10 mm cytoplasmic Mg(2+) because raising [Mg(2+)] strongly inhibits Ca(2+) efflux through the RyRs. In type I fibres of Old subjects, SR Ca(2+) accumulation in the presence of 1 mm Mg(2+) approached saturation at shorter loading times than in Young subjects, consistent with Ca(2+) leakage limiting net uptake, and raising [Mg(2+)] to 10 mm in such fibres increased maximal SR Ca(2+) accumulation. No significant differences were seen in type II fibres. Treatment with dithiothreitol (10 mm for 5 min), a strong reducing agent, also increased maximal SR Ca(2+) accumulation at 1 mm Mg(2+) in type I fibres of Old subjects but not in other fibres. The densities of dihydropyridine receptors and RyRs were not significantly different in muscles of Old relative to Young subjects. These findings indicate that Ca(2+) leakage from the SR is increased in type I fibres in Old subjects by reversible oxidative modification of the RyRs; this increased SR Ca(2+) leak is expected to have both direct and indirect deleterious effects on Ca(2+) movements and muscle function.
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Affiliation(s)
- C R Lamboley
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.,School of Life Sciences, La Trobe University, Melbourne, VIC 3086, Australia
| | - V L Wyckelsma
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - M J McKenna
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
| | - R M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - G D Lamb
- School of Life Sciences, La Trobe University, Melbourne, VIC 3086, Australia
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Hunter SK. Sex differences in fatigability of dynamic contractions. Exp Physiol 2015; 101:250-5. [PMID: 26440505 DOI: 10.1113/ep085370] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/30/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? Women are usually less fatigable than men for isometric fatiguing contractions of similar intensity, but whether this occurs for dynamic tasks is less clear. This review presents evidence that the sex difference in muscle fatigue of repeated dynamic contractions is specific to the task requirements, including the velocity of shortening and the muscle group involved. What advances does it highlight? Contractile mechanisms are responsible for the sex differences in muscle fatigue for slow-velocity and low-load dynamic tasks. The variability of the sex difference in fatigability among dynamic tasks has implications for fatiguing contractions prescribed in training and rehabilitation to men and women. Women are usually less fatigable than men during single-limb isometric contractions, primarily because of sex-related differences in contractile mechanisms. It is less clear whether these sex differences in muscle fatigue occur for dynamic fatiguing tasks. This review highlights new findings that the sex difference in fatigability for dynamic shortening contractions with a single limb is dependent on the contraction velocity and the muscle group involved. Recent studies demonstrate that women are less fatigable than men for a dynamic task as follows: (i) the elbow-flexor muscles at slow- but not high-velocity contractions; and (ii) the knee-extensor muscles when muscle fatigue was quantified as a reduction in the maximal voluntary isometric contraction force after the dynamic fatiguing task. Contractile mechanisms are responsible for the sex difference in muscle fatigue of the dynamic contractions, with no evidence for a sex difference in the reduction in voluntary activation (i.e. central fatigue). Thus, these findings indicate that the sex difference in muscle fatigue of dynamic contractions is task specific. These data also challenge the assumption that men and women respond in a similar manner to training and rehabilitation that involve fatiguing contractions to overload the neuromuscular system. There is, however, a tremendous opportunity for conducting high-impact studies to gain insight into those factors that define the sex-based differences in muscle fatigue during dynamic tasks. Such studies can define the boundaries to human performance in both men and women during athletic endeavours, ergonomic tasks and rehabilitation.
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Affiliation(s)
- Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
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Lamboley CR, Wyckelsma VL, Dutka TL, McKenna MJ, Murphy RM, Lamb GD. Contractile properties and sarcoplasmic reticulum calcium content in type I and type II skeletal muscle fibres in active aged humans. J Physiol 2015; 593:2499-514. [PMID: 25809942 DOI: 10.1113/jp270179] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/23/2015] [Indexed: 01/25/2023] Open
Abstract
KEY POINTS Muscle weakness in old age is due in large part to an overall loss of skeletal muscle tissue, but it remains uncertain how much also stems from alterations in the properties of the individual muscle fibres. This study examined the contractile properties and amount of stored intracellular calcium in single muscle fibres of Old (70 ± 4 years) and Young (22 ± 3 years) adults. The maximum level of force production (per unit cross-sectional area) in fast twitch fibres in Old subjects was lower than in Young subjects, and the fibres were also less sensitive to activation by calcium. The amount of calcium stored inside muscle fibres and available to trigger contraction was also lower in both fast- and slow-twitch muscle fibres in the Old subjects. These findings indicate that muscle weakness in old age stems in part from an impaired capacity for force production in the individual muscle fibres. ABSTRACT This study examined the contractile properties and sarcoplasmic reticulum (SR) Ca(2+) content in mechanically skinned vastus lateralis muscle fibres of Old (70 ± 4 years) and Young (22 ± 3 years) humans to investigate whether changes in muscle fibre properties contribute to muscle weakness in old age. In type II fibres of Old subjects, specific force was reduced by ∼17% and Ca(2+) sensitivity was also reduced (pCa50 decreased ∼0.05 pCa units) relative to that in Young. S-Glutathionylation of fast troponin I (TnIf ) markedly increased Ca(2+) sensitivity in type II fibres, but the increase was significantly smaller in Old versus Young (+0.136 and +0.164 pCa unit increases, respectively). Endogenous and maximal SR Ca(2+) content were significantly smaller in both type I and type II fibres in Old subjects. In fibres of Young, the SR could be nearly fully depleted of Ca(2+) by a combined caffeine and low Mg(2+) stimulus, whereas in fibres of Old the amount of non-releasable Ca(2+) was significantly increased (by > 12% of endogenous Ca(2+) content). Western blotting showed an increased proportion of type I fibres in Old subjects, and increased amounts of calsequestrin-2 and calsequestrin-like protein. The findings suggest that muscle weakness in old age is probably attributable in part to (i) an increased proportion of type I fibres, (ii) a reduction in both maximum specific force and Ca(2+) sensitivity in type II fibres, and also a decreased ability of S-glutathionylation of TnIf to counter the fatiguing effects of metabolites on Ca(2+) sensitivity, and (iii) a reduction in the amount of releasable SR Ca(2+) in both fibre types.
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Affiliation(s)
- C R Lamboley
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia
| | - V L Wyckelsma
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia.,La Trobe Rural Health School, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - T L Dutka
- School of Life Sciences, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - M J McKenna
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia
| | - R M Murphy
- School of Molecular Sciences, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - G D Lamb
- School of Life Sciences, La Trobe University, Melbourne, Victoria, 3086, Australia
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Frontera WR, Ochala J. Skeletal muscle: a brief review of structure and function. Calcif Tissue Int 2015; 96:183-95. [PMID: 25294644 DOI: 10.1007/s00223-014-9915-y] [Citation(s) in RCA: 740] [Impact Index Per Article: 82.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/16/2014] [Indexed: 01/23/2023]
Abstract
Skeletal muscle is one of the most dynamic and plastic tissues of the human body. In humans, skeletal muscle comprises approximately 40% of total body weight and contains 50-75% of all body proteins. In general, muscle mass depends on the balance between protein synthesis and degradation and both processes are sensitive to factors such as nutritional status, hormonal balance, physical activity/exercise, and injury or disease, among others. In this review, we discuss the various domains of muscle structure and function including its cytoskeletal architecture, excitation-contraction coupling, energy metabolism, and force and power generation. We will limit the discussion to human skeletal muscle and emphasize recent scientific literature on single muscle fibers.
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Affiliation(s)
- Walter R Frontera
- Department of Physical Medicine and Rehabilitation, Vanderbilt University School of Medicine, Suite 1318, 2201 Children's Way, Nashville, TN, 37212, USA,
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Reggiani C. Calcium handling in muscle fibres of mice and men: evolutionary adaptation in different species to optimize performance and save energy. J Physiol 2015; 592:1173-4. [PMID: 24634016 DOI: 10.1113/jphysiol.2014.272344] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Altered Ca2+ kinetics associated with α-actinin-3 deficiency may explain positive selection for ACTN3 null allele in human evolution. PLoS Genet 2015; 11:e1004862. [PMID: 25590636 PMCID: PMC4295894 DOI: 10.1371/journal.pgen.1004862] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/29/2014] [Indexed: 11/28/2022] Open
Abstract
Over 1.5 billion people lack the skeletal muscle fast-twitch fibre protein α-actinin-3 due to homozygosity for a common null polymorphism (R577X) in the ACTN3 gene. α-Actinin-3 deficiency is detrimental to sprint performance in elite athletes and beneficial to endurance activities. In the human genome, it is very difficult to find single-gene loss-of-function variants that bear signatures of positive selection, yet intriguingly, the ACTN3 null variant has undergone strong positive selection during recent evolution, appearing to provide a survival advantage where food resources are scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 KO mouse results in a shift in fast-twitch fibres towards oxidative metabolism, which would be more “energy efficient” in famine, and beneficial to endurance performance. Prolonged exposure to cold can also induce changes in skeletal muscle similar to those observed with endurance training, and changes in Ca2+ handling by the sarcoplasmic reticulum (SR) are a key factor underlying these adaptations. On this basis, we explored the effects of α-actinin-3 deficiency on Ca2+ kinetics in single flexor digitorum brevis muscle fibres from Actn3 KO mice, using the Ca2+-sensitive dye fura-2. Compared to wild-type, fibres of Actn3 KO mice showed: (i) an increased rate of decay of the twitch transient; (ii) a fourfold increase in the rate of SR Ca2+ leak; (iii) a threefold increase in the rate of SR Ca2+ pumping; and (iv) enhanced maintenance of tetanic Ca2+ during fatigue. The SR Ca2+ pump, SERCA1, and the Ca2+-binding proteins, calsequestrin and sarcalumenin, showed markedly increased expression in muscles of KO mice. Together, these changes in Ca2+ handling in the absence of α-actinin-3 are consistent with cold acclimatisation and thermogenesis, and offer an additional explanation for the positive selection of the ACTN3 577X null allele in populations living in cold environments during recent evolution. α-Actinin-3 is a protein found inside the muscles of most people around the world. It is encoded by a gene called ACTN3, popularly known as “the gene for speed.” In 1.5 billion people, a certain variation in the genetic sequence of their ACTN3 gene causes their muscles to produce no α-actinin-3 protein at all. These people have no muscle disease; however, in elite athletes, a lack of α-actinin-3 seems to be beneficial for endurance activities and detrimental to sprinting activities. Intriguingly, α-actinin-3 deficiency varies in frequency across the globe, being most common in European and Asian populations and least common in African populations. During recent human evolution, there appears to have been strong positive selection for α-actinin-3 deficiency in places where food resources are relatively scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 knockout (KO) mouse causes a shift towards more “energy efficient” forms of muscle metabolism which would enhance survival in times of famine, and benefit endurance performance. Our present study, using single muscle fibres from Actn3 KO mice, demonstrates changes in calcium handling that would adapt muscles to cold environments and provide a survival advantage in cold climates.
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Abstract
Muscular dystrophies are a group of diseases characterised by the primary wasting of skeletal muscle, which compromises patient mobility and in the most severe cases originate a complete paralysis and premature death. Existing evidence implicates calcium dysregulation as an underlying crucial event in the pathophysiology of several muscular dystrophies, such as dystrophinopathies, calpainopathies or myotonic dystrophy among others. Duchenne muscular dystrophy is the most frequent myopathy in childhood, and calpainopathy or LGMD2A is the most common form of limb-girdle muscular dystrophy, whereas myotonic dystrophy is the most frequent inherited muscle disease worldwide. In this review, we summarise recent advances in our understanding of calcium ion cycling through the sarcolemma, the sarcoplasmic reticulum and mitochondria, and its involvement in the pathogenesis of these dystrophies. We also discuss some of the clinical implications of recent findings regarding Ca2+ handling as well as novel approaches to treat muscular dystrophies targeting Ca2+ regulatory proteins.
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Dutka TL, Lamboley CR, Murphy RM, Lamb GD. Acute effects of taurine on sarcoplasmic reticulum Ca2+ accumulation and contractility in human type I and type II skeletal muscle fibers. J Appl Physiol (1985) 2014; 117:797-805. [DOI: 10.1152/japplphysiol.00494.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Taurine occurs in high concentrations in muscle and is implicated in numerous physiological processes, yet its effects on many aspects of contractility remain unclear. Using mechanically skinned segments of human vastus lateralis muscle fibers, we characterized the effects of taurine on sarcoplasmic reticulum (SR) Ca2+ accumulation and contractile apparatus properties in type I and type II fibers. Prolonged myoplasmic exposure (>10 min) to taurine substantially increased the rate of accumulation of Ca2+ by the SR in both fiber types, with no change in the maximum amount accumulated; no such effect was found with carnosine. SR Ca2+ accumulation was similar with 10 or 20 mM taurine, but was significantly slower at 5 mM taurine. Cytoplasmic taurine (20 mM) had no detectable effects on the responsiveness of the Ca2+ release channels in either fiber type. Taurine caused a small increase in Ca2+ sensitivity of the contractile apparatus in type I fibers, but type II fibers were unaffected; maximum Ca2+-activated force was unchanged in both cases. The effects of taurine on SR Ca2+ accumulation 1) only became apparent after prolonged cytoplasmic exposure, and 2) persisted for some minutes after complete removal of taurine from the cytoplasm, consistent with the hypothesis that the effects were due to an action of taurine from inside the SR. In summary, taurine potentiates the rate of SR Ca2+ uptake in both type I and type II human fibers, possibly via an action from within the SR lumen, with the degree of potentiation being significantly reduced at low physiological taurine levels.
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Affiliation(s)
- T. L. Dutka
- Department of Zoology, La Trobe University, Melbourne, Victoria, Australia; and
| | - C. R. Lamboley
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
| | - R. M. Murphy
- Department of Zoology, La Trobe University, Melbourne, Victoria, Australia; and
| | - G. D. Lamb
- Department of Zoology, La Trobe University, Melbourne, Victoria, Australia; and
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