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Cao M, Sheng R, Sun Y, Cao Y, Wang H, Zhang M, Pu Y, Gao Y, Zhang Y, Lu P, Teng G, Wang Q, Rui Y. Delivering Microrobots in the Musculoskeletal System. NANO-MICRO LETTERS 2024; 16:251. [PMID: 39037551 PMCID: PMC11263536 DOI: 10.1007/s40820-024-01464-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 06/16/2024] [Indexed: 07/23/2024]
Abstract
Disorders of the musculoskeletal system are the major contributors to the global burden of disease and current treatments show limited efficacy. Patients often suffer chronic pain and might eventually have to undergo end-stage surgery. Therefore, future treatments should focus on early detection and intervention of regional lesions. Microrobots have been gradually used in organisms due to their advantages of intelligent, precise and minimally invasive targeted delivery. Through the combination of control and imaging systems, microrobots with good biosafety can be delivered to the desired area for treatment. In the musculoskeletal system, microrobots are mainly utilized to transport stem cells/drugs or to remove hazardous substances from the body. Compared to traditional biomaterial and tissue engineering strategies, active motion improves the efficiency and penetration of local targeting of cells/drugs. This review discusses the frontier applications of microrobotic systems in different tissues of the musculoskeletal system. We summarize the challenges and barriers that hinder clinical translation by evaluating the characteristics of different microrobots and finally point out the future direction of microrobots in the musculoskeletal system.
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Affiliation(s)
- Mumin Cao
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Renwang Sheng
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Yimin Sun
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 210009, People's Republic of China
| | - Ying Cao
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 210009, People's Republic of China
| | - Hao Wang
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Ming Zhang
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Yunmeng Pu
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
| | - Yucheng Gao
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Yuanwei Zhang
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Panpan Lu
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China
| | - Gaojun Teng
- Center of Interventional Radiology and Vascular Surgery, Department of Radiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China.
| | - Qianqian Wang
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 210009, People's Republic of China.
| | - Yunfeng Rui
- Department of Orthopaedics, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, People's Republic of China.
- School of Medicine, Southeast University, Nanjing, 210009, People's Republic of China.
- Orthopaedic Trauma Institute (OTI), Southeast University, Nanjing, 210009, People's Republic of China.
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Carr BR, Neal TW, Finn RA, Luo X, Stone JA. The effect of mandibular advancement for mandibular deficiency dentofacial deformities on laryngeal grade and intubation difficulty: a preliminary study. Oral Surg Oral Med Oral Pathol Oral Radiol 2023; 136:410-416. [PMID: 37612165 DOI: 10.1016/j.oooo.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 03/18/2023] [Indexed: 08/25/2023]
Abstract
OBJECTIVE The purpose of this study was to evaluate mandibular advancement for cases of mandibular deficiency with changes in vocal cord grade and intubation difficulty at subsequent surgery requiring intubation. STUDY DESIGN This retrospective case series included patients with a diagnosis of mandibular deficiency (Class II skeletal dentofacial deformity) who underwent mandibular advancement surgery (T1) followed by a subsequent surgery (T2) which required intubation. The primary predictor variable was mandibular advancement. The primary outcome variable was the change in laryngeal grade-Cormack and Lehane-after mandibular advancement. A secondary outcome was intubation difficulty after mandibular advancement. RESULTS Eight patients were included in the study. At T1, the average laryngeal grade was 1.6. There was 1 difficult intubation. The average time to T2 was 9 months. At T2, all patients were intubated on their first attempt, and all had a Cormack-Lehane Grade I view of the vocal cords. There were no difficult intubations at T2. Analysis showed a significant association between mandibular advancement and laryngeal grade at T2 (P = .03; 95% CI 0.07-1.13). CONCLUSIONS This preliminary investigation found an association between mandibular advancement for cases of mandibular and improved laryngeal grade at subsequent intubation without any difficult intubations.
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Affiliation(s)
- Brian R Carr
- Department of Surgery, Division of Oral and Maxillofacial Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Timothy W Neal
- Department of Surgery, Division of Oral and Maxillofacial Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Richard A Finn
- Department of Surgery, Division of Oral and Maxillofacial Surgery, Department of Cell Biology-Anatomy, University of Texas Southwestern Medical Center; Oral and Maxillofacial, Surgery, Veterans Affairs North Texas Health Care System, Dallas, TX, USA
| | - Xi Luo
- Department of Anesthesiology & Pain Management, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joshua A Stone
- Department of Surgery, Division of Oral and Maxillofacial Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Tan Y, Martin TG, Harrison BC, Leinwand LA. Utility of the burmese Python as a model for studying plasticity of extreme physiological systems. J Muscle Res Cell Motil 2023; 44:95-106. [PMID: 36316565 PMCID: PMC10149580 DOI: 10.1007/s10974-022-09632-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/30/2022] [Indexed: 03/18/2023]
Abstract
Non-traditional animal models present an opportunity to discover novel biology that has evolved to allow such animals to survive in extreme environments. One striking example is the Burmese python (Python molurus bivittatus), which exhibits extreme physiological adaptation in various metabolic organs after consuming a large meal following long periods of fasting. The response to such a large meal in pythons involves a dramatic surge in metabolic rate, lipid overload in plasma, and massive but reversible organ growth through the course of digestion. Multiple studies have reported the physiological responses in post-prandial pythons, while the specific molecular control of these processes is less well-studied. Investigating the mechanisms that coordinate organ growth and adaptive responses offers the opportunity to gain novel insight that may be able to treat various pathologies in humans. Here, we summarize past research on the post-prandial physiological changes in the Burmese python with a focus on the gastrointestinal tract, heart, and liver. Specifically, we address our recent molecular discoveries in the post-prandial python liver which demonstrate transient adaptations that may reveal new therapeutic targets. Lastly, we explore new biology of the aquaporin 7 gene that is potently upregulated in mammalian cardiac myocytes by circulating factors in post-prandial python plasma.
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Affiliation(s)
- Yuxiao Tan
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder. 3415 Colorado Ave, UCB 596, 80309, Boulder, CO, USA
| | - Thomas G Martin
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder. 3415 Colorado Ave, UCB 596, 80309, Boulder, CO, USA
| | - Brooke C Harrison
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder. 3415 Colorado Ave, UCB 596, 80309, Boulder, CO, USA
| | - Leslie A Leinwand
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder. 3415 Colorado Ave, UCB 596, 80309, Boulder, CO, USA.
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4
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Wu S, Ruan L, Wu J, Wu M, Chu LT, Kwong HK, Lam ML, Chen TH. Scalable pattern formation of skeletal myotubes by synergizing microtopographic cues and chiral nematics of cells. Biofabrication 2023; 15. [PMID: 36791461 DOI: 10.1088/1758-5090/acbc4d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/15/2023] [Indexed: 02/17/2023]
Abstract
Topographical cues have been widely used to facilitate cell fusion in skeletal muscle formation. However, an unexpected yet consistent chiral orientation of myotubes deviating from the groove boundaries is commonly observed but has long been unattended. In this study, we report a method to guide the formation of skeletal myotubes into scalable and controlled patterns. By inducing C2C12 myoblasts onto grooved patterns with different widths (from 0.4 to 200μm), we observed an enhanced chiral orientation of cells developing on wide grooves (50 and 100μm width) since the first day of induction. Active chiral nematics of cells involving cell migration and chiral rotation of the cell nucleus subsequently led to a unified chiral orientation of the myotubes. Importantly, these chiral myotubes were formed with enhanced length, diameter, and contractility on wide grooves. Treatment of latrunculin A (Lat A) suppressed the chiral rotation and migration of cells as well as the myotube formation, suggesting the essence of chiral nematics of cells for myogenesis. Finally, by arranging wide grooved/striped patterns with corresponding compensation angles to synergize microtopographic cues and chiral nematics of cells, intricate and scalable patterns of myotubes were formed, providing a strategy for engineering skeletal muscle tissue formation.
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Affiliation(s)
- Siying Wu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Lingyan Ruan
- School of Creative Media, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Jianpeng Wu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Minghui Wu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Lok Ting Chu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Hoi Kwan Kwong
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Miu Ling Lam
- School of Creative Media, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Ting-Hsuan Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
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5
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An Early and Sustained Inflammatory State Induces Muscle Changes and Establishes Obesogenic Characteristics in Wistar Rats Exposed to the MSG-Induced Obesity Model. Int J Mol Sci 2023; 24:ijms24054730. [PMID: 36902158 PMCID: PMC10003260 DOI: 10.3390/ijms24054730] [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: 10/21/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 03/05/2023] Open
Abstract
The model of obesity induced by monosodium glutamate cytotoxicity on the hypothalamic nuclei is widely used in the literature. However, MSG promotes persistent muscle changes and there is a significant lack of studies that seek to elucidate the mechanisms by which damage refractory to reversal is established. This study aimed to investigate the early and chronic effects of MSG induction of obesity upon systemic and muscular parameters of Wistar rats. The animals were exposed to MSG subcutaneously (4 mg·g-1 b.w.) or saline (1.25 mg·g-1 b.w.) daily from PND01 to PND05 (n = 24). Afterwards, in PND15, 12 animals were euthanized to determine the plasma and inflammatory profile and to assess muscle damage. In PND142, the remaining animals were euthanized, and samples for histological and biochemical analyses were obtained. Our results suggest that early exposure to MSG reduced growth, increased adiposity, and inducted hyperinsulinemia and a pro-inflammatory scenario. In adulthood, the following were observed: peripheral insulin resistance, increased fibrosis, oxidative distress, and a reduction in muscle mass, oxidative capacity, and neuromuscular junctions, increased fibrosis, and oxidative distress. Thus, we can conclude that the condition found in adult life and the difficulty restoring in the muscle profile is related to the metabolic damage established early on.
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6
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Mowafy ZME, Fouad FAE, Shehata SR, Abd El Salam AH, Ali KM. Effect of progressive resistance training on post prostatectomy stress urinary incontinence: A randomized controlled study. FIZJOTERAPIA POLSKA 2022; 22:48-55. [DOI: 10.56984/8zg1a6it9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Purpose. The aim of this study was to investigate the effectiveness of progressive resistance training on post prostatectomy stress urinary incontinence. Materials and Methods. Sixty male patients who complaint from post prostatectomy stress urinary incontinence were participated in this study, their ages were ranged from 40 to 75 years and they were randomly assigned into two equal groups. Group (A) (Study group): This group included 30 patients who had post prostatectomy stress urinary incontinence and they received progressive resistance training in addition to interferential current stimulation and routine medical treatment three sessions per week for 12 weeks. Group (B) (Control group): This group included 30 patients who had post prostatectomy stress urinary incontinence and they received interferential current stimulation and routine medical treatment three sessions per week for 12 weeks. Pre- and post-treatment assessment using DANTIC UD 5000/5500 Urodynamic investigation system & Severity index scale were done for all patients. Results. The obtained results of the present study indicated significant difference of all measured variables when comparing between pre and post- treatment values of the groups (A and B) and revealed significant difference when comparing between post- treatment values of the groups (A and B) in favor of group (A). Conclusion. Progressive resistance training had an effect on reducing post prostatectomy stress urinary incontinence and there was significant difference when comparing between post-treatment values of the groups (A and B) in favor of group (A).
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Affiliation(s)
| | | | | | - Aml Hamdy Abd El Salam
- Department of Physical Therapy for Surgery, Faculty of Physical Therapy, Cairo University, Cairo, Egypt
| | - Khadra Mohamed Ali
- Department of Physical Therapy for Surgery, Faculty of Physical Therapy, Cairo University, Cairo, Egypt
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7
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Liu L, Wu J, Chen B, Gao J, Li T, Ye Y, Tian H, Wang S, Wang F, Jiang J, Ou J, Tong F, Peng F, Tu Y. Magnetically Actuated Biohybrid Microswimmers for Precise Photothermal Muscle Contraction. ACS NANO 2022; 16:6515-6526. [PMID: 35290021 DOI: 10.1021/acsnano.2c00833] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Various strategies have been designed for myotube contraction and skeletal muscle stimulation in recent years, aiming in the field of skeletal muscle tissue engineering and bionics. However, most of the current approaches lack controllability and adaptability for precise stimulation, especially at the microlevel. Herein, wireless and precise activation of muscle by using magnetic biohybrid microswimmers in combination with near-infrared (NIR) laser irradiation is successfully demonstrated. Biohybrid microswimmers are fabricated by dip-coating superparamagnetic Fe3O4 nanoparticles onto the chlorella microalgae, thus endowing robust navigation in various biological media due to magnetic actuation. Under the guidance of a rotating magnetic field, the engineered microswimmer can achieve precise motion toward a single C2C12-derived myotube. Upon NIR irradiation, the photothermal effect from the incorporated Fe3O4 nanoparticles results in local temperature increments of approximately 5 °C in the targeted myotube, which could efficiently trigger the contraction of myotube. The mechanism underlying this phenomenon is a Ca2+-independent case involving direct actin-myosin interactions. In vivo muscle fiber contraction and histological test further demonstrate the effectiveness and biosafety of our design. The as-developed biohybrid microswimmer-based strategy is possible to provide a renovation for tissue engineering and bionics.
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Affiliation(s)
- Lu Liu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
- Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Juanyan Wu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Bin Chen
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Junbin Gao
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Ting Li
- School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yicheng Ye
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Hao Tian
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Shuanghu Wang
- The Laboratory of Clinical Pharmacy, The Sixth Affiliated Hospital of Wenzhou Medical University, The People's Hospital of Lishui, Lishui 323020, China
| | - Fei Wang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Jiamiao Jiang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Juanfeng Ou
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Fei Tong
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
| | - Fei Peng
- School of Materials Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yingfeng Tu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou 510515, China
- Department of Pharmacy, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
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8
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Cieri RL, Dick TJM, Morris JS, Clemente CJ. Scaling of fibre area and fibre glycogen concentration in the hindlimb musculature of monitor lizards: implications for locomotor performance with increasing body size. J Exp Biol 2022; 225:274383. [PMID: 35258618 DOI: 10.1242/jeb.243380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/22/2022]
Abstract
A considerable biomechanical challenge faces larger terrestrial animals as the demands of body support scale with body mass (Mb), while muscle force capacity is proportional to muscle cross-sectional area, which scales with Mb2/3. How muscles adjust to this challenge might be best understood by examining varanids, which vary by five orders of magnitude in size without substantial changes in posture or body proportions. Muscle mass, fascicle length and physiological cross-sectional area all scale with positive allometry, but it remains unclear, however, how muscles become larger in this clade. Do larger varanids have more muscle fibres, or does individual fibre cross-sectional area (fCSA) increase? It is also unknown if larger animals compensate by increasing the proportion of fast-twitch (higher glycogen concentration) fibres, which can produce higher force per unit area than slow-twitch fibres. We investigated muscle fibre area and glycogen concentration in hindlimb muscles from varanids ranging from 105 g to 40,000 g. We found that fCSA increased with modest positive scaling against body mass (Mb0.197) among all our samples, and ∝Mb0.278 among a subset of our data consisting of never-frozen samples only. The proportion of low-glycogen fibres decreased significantly in some muscles but not others. We compared our results with the scaling of fCSA in different groups. Considering species means, fCSA scaled more steeply in invertebrates (∝Mb0.575), fish (∝Mb0.347) and other reptiles (∝Mb0.308) compared with varanids (∝Mb0.267), which had a slightly higher scaling exponent than birds (∝Mb0.134) and mammals (∝Mb0.122). This suggests that, while fCSA generally increases with body size, the extent of this scaling is taxon specific, and may relate to broad differences in locomotor function, metabolism and habitat between different clades.
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Affiliation(s)
- Robert L Cieri
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia
| | - Taylor J M Dick
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia.,School of Biomedical Sciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jeremy S Morris
- Department of Biology, Wofford College, Spartanburg, SC 29303, USA
| | - Christofer J Clemente
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia.,School of Biomedical Sciences, University of Queensland, St. Lucia, QLD 4072, Australia
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9
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de Goede P, Wüst RCI, Schomakers BV, Denis S, Vaz FM, Pras-Raves ML, van Weeghel M, Yi CX, Kalsbeek A, Houtkooper RH. Time-restricted feeding during the inactive phase abolishes the daily rhythm in mitochondrial respiration in rat skeletal muscle. FASEB J 2022; 36:e22133. [PMID: 35032416 DOI: 10.1096/fj.202100707r] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 11/26/2021] [Accepted: 12/17/2021] [Indexed: 01/06/2023]
Abstract
Shift-workers show an increased incidence of type 2 diabetes mellitus (T2DM). A possible mechanism is the disruption of the circadian timing of glucose homeostasis. Skeletal muscle mitochondrial function is modulated by the molecular clock. We used time-restricted feeding (TRF) during the inactive phase to investigate how mistimed feeding affects muscle mitochondrial metabolism. Rats on an ad libitum (AL) diet were compared to those that could eat only during the light (inactive) or dark (active) phase. Mitochondrial respiration, metabolic gene expressions, and metabolite concentrations were determined in the soleus muscle. Rats on AL feeding or dark-fed TRF showed a clear daily rhythm in muscle mitochondrial respiration. This rhythm in mitochondrial oxidative phosphorylation capacity was abolished in light-fed TRF animals and overall 24h respiration was lower. The expression of several genes involved in mitochondrial biogenesis and the fission/fusion machinery was altered in light-fed animals. Metabolomics analysis indicated that light-fed animals had lost rhythmic levels of α-ketoglutarate and citric acid. Contrastingly, lipidomics showed that light-fed animals abundantly gained rhythmicity in levels of triglycerides. Furthermore, while the RER shifted entirely with the food intake in the light-fed animals, many measured metabolic parameters (e.g., activity and mitochondrial respiration) did not strictly align with the shifted timing of food intake, resulting in a mismatch between expected metabolic supply/demand (as dictated by the circadian timing system and light/dark-cycle) and the actual metabolic supply/demand (as dictated by the timing of food intake). These data suggest that shift-work impairs mitochondrial metabolism and causes metabolic inflexibility, which can predispose to T2DM.
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Affiliation(s)
- Paul de Goede
- Laboratory of Endocrinology, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Hypothalamic Integration Mechanisms Group, Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Rob C I Wüst
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Bauke V Schomakers
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Core Facility Metabolomics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Simone Denis
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Frédéric M Vaz
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Core Facility Metabolomics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Mia L Pras-Raves
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Core Facility Metabolomics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Michel van Weeghel
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Core Facility Metabolomics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Chun-Xia Yi
- Laboratory of Endocrinology, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Andries Kalsbeek
- Laboratory of Endocrinology, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Hypothalamic Integration Mechanisms Group, Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.,Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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10
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Ahn KH, Kim S, Yang M, Lee DW. A Pillar-Based High-Throughput Myogenic Differentiation Assay to Assess Drug Safety. Molecules 2021; 26:molecules26195805. [PMID: 34641349 PMCID: PMC8510049 DOI: 10.3390/molecules26195805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/05/2021] [Accepted: 09/15/2021] [Indexed: 11/16/2022] Open
Abstract
High-throughput, pillar-strip-based assays have been proposed as a drug-safety screening tool for developmental toxicity. In the assay described here, muscle cell culture and differentiation were allowed to occur at the end of a pillar strip (eight pillars) compatible with commercially available 96-well plates. Previous approaches to characterize cellular differentiation with immunostaining required a burdensome number of washing steps; these multiple washes also resulted in a high proportion of cellular loss resulting in poor yield. To overcome these limitations, the approach described here utilizes cell growth by easily moving the pillars for washing and immunostaining without significant loss of cells. Thus, the present pillar-strip approach is deemed suitable for monitoring high-throughput myogenic differentiation. Using this experimental high-throughput approach, eight drugs (including two well-known myogenic inhibitory drugs) were tested at six doses in triplicate, which allows for the generation of dose–response curves of nuclei and myotubes in a 96-well platform. As a result of comparing these F-actin (an actin-cytoskeleton protein), nucleus, and myotube data, two proposed differentiation indices—curve-area-based differentiation index (CA-DI) and maximum-point-based differentiation index (MP-DI) were generated. Both indices successfully allowed for screening of high-myogenic inhibitory drugs, and the maximum-point-based differentiation index (MP-DI) experimentally demonstrated sensitivity for quantifying drugs that inhibited myogenic differentiation.
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Affiliation(s)
- Kyeong Hwan Ahn
- Department of Biomedical Engineering, Konyang University, Daejeon 35365, Korea; (K.H.A.); (S.K.)
| | - Sooil Kim
- Department of Biomedical Engineering, Konyang University, Daejeon 35365, Korea; (K.H.A.); (S.K.)
| | - Mihi Yang
- Department of Toxicology, College of Pharmacy, Sookmyung Women’s University, Seoul 04310, Korea
- Correspondence: (M.Y.); (D.W.L.); Tel.: +82-10-2546-9586 (D.W.L.)
| | - Dong Woo Lee
- Department of Biomedical Engineering, Konyang University, Daejeon 35365, Korea; (K.H.A.); (S.K.)
- Central R & D Center, Medical & Bio Decision (MBD) Co., Ltd., Suwon 16229, Korea
- Correspondence: (M.Y.); (D.W.L.); Tel.: +82-10-2546-9586 (D.W.L.)
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11
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da Conceição Pereira S, Manhães-de-Castro R, Visco DB, de Albuquerque GL, da Silva Calado CMS, da Silva Souza V, Toscano AE. Locomotion is impacted differently according to the perinatal brain injury model: Meta-analysis of preclinical studies with implications for cerebral palsy. J Neurosci Methods 2021; 360:109250. [PMID: 34116077 DOI: 10.1016/j.jneumeth.2021.109250] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Different approaches to reproduce cerebral palsy (CP) in animals, contribute to the knowledge of the pathophysiological mechanism of this disease and provide a basis for the development of intervention strategies. Locomotion and coordination are the main cause of disability in CP, however, few studies highlight the quantitative differences of CP models, on locomotion parameters, considering the methodologies to cause brain lesions in the perinatal period. METHODS Studies with cerebral palsy animal models that assess locomotion parameters were systematically retrieved from Medline/PubMed, SCOPUS, LILACS, and Web of Science. Methodological evaluation of included studies and quantitative assessment of locomotion parameters were performed after eligibility screening. RESULTS CP models were induced by hypoxia-ischemia (HI), Prenatal ischemia (PI), lipopolysaccharide inflammation (LPS), intraventricular haemorrhage (IVH), anoxia (A), sensorimotor restriction (SR), and a combination of different models. Overall, 63 studies included in qualitative synthesis showed a moderate quality of evidence. 16 studies were included in the quantitative meta-analysis. Significant reduction was observed in models that combined LPS with HI related to distance traveled (SMD -7.24 95 % CI [-8.98, -5.51], Z = 1.18, p < 0.00001) and LPS with HI or anoxia with sensory-motor restriction (SMD -6.01, 95 % CI [-7.67, -4.35], Z = 7.11), or IVH (SMD -4.91, 95 % CI [-5.84, -3.98], Z = 10.31, p < 0.00001) related to motor coordination. CONCLUSION The combination of different approaches to reproduce CP in animals causes greater deficits in locomotion and motor coordination from the early stages of life to adulthood. These findings contribute to methodological refinement, reduction, and replacement in animal experimentation, favoring translational purposes.
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Affiliation(s)
- Sabrina da Conceição Pereira
- Posgraduate Program in Neuropsychiatry and Behavior Sciences, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Raul Manhães-de-Castro
- Posgraduate Program in Neuropsychiatry and Behavior Sciences, Federal University of Pernambuco, Recife, Pernambuco, Brazil; Studies in Nutrition and Phenotypic Plasticity Unit, Department of Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil; Postgraduate Program in Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Diego Bulcão Visco
- Studies in Nutrition and Phenotypic Plasticity Unit, Department of Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil; Postgraduate Program in Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | | | | | - Vanessa da Silva Souza
- Posgraduate Program in Neuropsychiatry and Behavior Sciences, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Ana Elisa Toscano
- Posgraduate Program in Neuropsychiatry and Behavior Sciences, Federal University of Pernambuco, Recife, Pernambuco, Brazil; Studies in Nutrition and Phenotypic Plasticity Unit, Department of Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil; Postgraduate Program in Nutrition, Federal University of Pernambuco, Recife, Pernambuco, Brazil; Department of Nursing, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil.
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12
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Chang YC, Liu HW, Chan YC, Hu SH, Liu MY, Chang SJ. The green tea polyphenol epigallocatechin-3-gallate attenuates age-associated muscle loss via regulation of miR-486-5p and myostatin. Arch Biochem Biophys 2020; 692:108511. [PMID: 32710883 DOI: 10.1016/j.abb.2020.108511] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022]
Abstract
(-)-Epigallocatechin-3-gallate (EGCG), the most abundant catechin component in green tea, has been reported to attenuate age-associated insulin resistance, lipogenesis and loss of muscle mass through restoring Akt activity in skeletal muscle in our previous and present studies. Accumulated data has suggested that polyphenols regulate signaling pathways involved in aging process such as inflammation and oxidative stress via modulation of miRNA expression. Here we found that miRNA-486-5p was significantly decreased in both aged senescence accelerated mouse-prone 8 (SAMP8) mice and late passage C2C12 cells. Thus, we further investigated the regulatory effect of EGCG on miRNA-486-5p expression in age-regulated muscle loss. SAMP8 mice were fed with chow diet containing without or with 0.32% EGCG from aged 32 weeks for 8 weeks. Early passage (<12 passages) and late passage (>30 passages) of C2C12 cells were treated without or with EGCG at concentrations of 50 μM for 24h. Our data showed that EGCG supplementation increased miRNA-486-5p expression in both aged SAMP8 mice and late passage C2C12 cells. EGCG stimulated AKT phosphorylation and inhibited FoxO1a-mediated MuRF1 and Atrogin-1 transcription via up-regulating the expression of miR-486 in skeletal muscle of 40-wk-old SAMP8 mice as well as late passage C2C12 cells. In addition, myostatin expression was increased in late passage C2C12 cells and anti-myostatin treatment upregulated the expression of miR-486-5p. Our results identify a unique mechanism of a dietary constituent of green tea and suggest that use of EGCG or compounds derived from it attenuates age-associated muscle loss via myostatin/miRNAs/ubiquitin-proteasome signaling.
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Affiliation(s)
- Yun-Ching Chang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan; Department of Nursing, Shu-Zen College of Medicine and Management, Kaohsiung, Taiwan.
| | - Hung-Wen Liu
- Department of Physical Education, National Taiwan Normal University, Taipei, Taiwan.
| | - Yin-Ching Chan
- Department of Food and Nutrition, Providence University, Taichung, Taiwan.
| | - Shu-Hui Hu
- Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan.
| | - Ming-Yi Liu
- Department of Long Term Care, Wu Feng University, Chiayi County, Taiwan; Department of Senior Welfare and Services, Southern Taiwan University of Science and Technology. No. 1, Nan-Tai Street, Yongkang Dist., Tainan City, Taiwan.
| | - Sue-Joan Chang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
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13
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Figueiredo VC. Revisiting the roles of protein synthesis during skeletal muscle hypertrophy induced by exercise. Am J Physiol Regul Integr Comp Physiol 2019; 317:R709-R718. [PMID: 31508978 DOI: 10.1152/ajpregu.00162.2019] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein synthesis is deemed the underpinning mechanism enhancing protein balance required for skeletal muscle hypertrophy in response to resistance exercise. The current model of skeletal muscle hypertrophy induced by resistance training states that the acute increase in the rates of protein synthesis after each bout of resistance exercise is the basis for muscle growth. Within this paradigm, each resistance exercise session would add a specific amount of muscle mass; therefore, muscle hypertrophy could be defined as the result of intermittent and short-lived increases in muscle protein synthesis rates following each resistance exercise session. Although a substantial amount of data has accumulated in the last decades regarding the acute changes in protein synthesis (or translational efficiency) following resistance exercise, considerable gaps on the mechanism of muscle growth still exist. Ribosome biogenesis and translational capacity have emerged as important mediators of skeletal muscle hypertrophy. Recent advances in the field have demonstrated that skeletal muscle hypertrophy is associated with markers of translational capacity and long-term changes in protein synthesis under resting conditions. This review will discuss the caveats of the current model of skeletal muscle hypertrophy induced by resistance training while proposing a working model that takes into consideration the novel data generated by independent laboratories utilizing different methodologies. It is argued, herein, that the role of protein synthesis in the current model of muscle hypertrophy warrants revisiting.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- College of Health Sciences, Department of Rehabilitation Sciences, the Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
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14
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Vitale JA, Bonato M, La Torre A, Banfi G. The Role of the Molecular Clock in Promoting Skeletal Muscle Growth and Protecting against Sarcopenia. Int J Mol Sci 2019; 20:ijms20174318. [PMID: 31484440 PMCID: PMC6747101 DOI: 10.3390/ijms20174318] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 12/12/2022] Open
Abstract
The circadian clock has a critical role in many physiological functions of skeletal muscle and is essential to fully understand the precise underlying mechanisms involved in these complex interactions. The importance of circadian expression for structure, function and metabolism of skeletal muscle is clear when observing the muscle phenotype in models of molecular clock disruption. Presently, the maintenance of circadian rhythms is emerging as an important new factor in human health, with disruptions linked to ageing, as well as to the development of many chronic diseases, including sarcopenia. Therefore, the aim of this review is to present the latest findings demonstrating how circadian rhythms in skeletal muscle are important for maintenance of the cellular physiology, metabolism and function of skeletal muscle. Moreover, we will present the current knowledge about the tissue-specific functions of the molecular clock in skeletal muscle.
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Affiliation(s)
- Jacopo A Vitale
- IRCCS Istituto Ortopedico Galeazzi, LaMSS-Laboratory of Movement and Sport Science, Via Giuseppe Galeazzi 4, 20161 Milano, Italy
| | - Matteo Bonato
- IRCCS Istituto Ortopedico Galeazzi, LaMSS-Laboratory of Movement and Sport Science, Via Giuseppe Galeazzi 4, 20161 Milano, Italy.
| | - Antonio La Torre
- IRCCS Istituto Ortopedico Galeazzi, LaMSS-Laboratory of Movement and Sport Science, Via Giuseppe Galeazzi 4, 20161 Milano, Italy
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Via Giuseppe Colombo 71, 20133 Milano, Italy
| | - Giuseppe Banfi
- IRCCS Istituto Ortopedico Galeazzi, LaMSS-Laboratory of Movement and Sport Science, Via Giuseppe Galeazzi 4, 20161 Milano, Italy
- Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milano, Italy
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15
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Oh HYP, Visvalingam V, Wahli W. The PPAR-microbiota-metabolic organ trilogy to fine-tune physiology. FASEB J 2019; 33:9706-9730. [PMID: 31237779 DOI: 10.1096/fj.201802681rr] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The human gut is colonized by commensal microorganisms, predominately bacteria that have coevolved in symbiosis with their host. The gut microbiota has been extensively studied in recent years, and many important findings on how it can regulate host metabolism have been unraveled. In healthy individuals, feeding timing and type of food can influence not only the composition but also the circadian oscillation of the gut microbiota. Host feeding habits thus influence the type of microbe-derived metabolites produced and their concentrations throughout the day. These microbe-derived metabolites influence many aspects of host physiology, including energy metabolism and circadian rhythm. Peroxisome proliferator-activated receptors (PPARs) are a group of ligand-activated transcription factors that regulate various metabolic processes such as fatty acid metabolism. Similar to the gut microbiota, PPAR expression in various organs oscillates diurnally, and studies have shown that the gut microbiota can influence PPAR activities in various metabolic organs. For example, short-chain fatty acids, the most abundant type of metabolites produced by anaerobic fermentation of dietary fibers by the gut microbiota, are PPAR agonists. In this review, we highlight how the gut microbiota can regulate PPARs in key metabolic organs, namely, in the intestines, liver, and muscle. Knowing that the gut microbiota impacts metabolism and is altered in individuals with metabolic diseases might allow treatment of these patients using noninvasive procedures such as gut microbiota manipulation.-Oh, H. Y. P., Visvalingam, V., Wahli, W. The PPAR-microbiota-metabolic organ trilogy to fine-tune physiology.
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Affiliation(s)
- Hui Yun Penny Oh
- Interdisciplinary Graduate School, Institute for Health Technologies, Nanyang Technological University, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Vivegan Visvalingam
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Walter Wahli
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Unité Mixte de Recherche (UMR) 1331, Institut National de la Recherche Agronomique (INRA)-ToxAlim, Toulouse, France.,Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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16
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Denes LT, Riley LA, Mijares JR, Arboleda JD, McKee K, Esser KA, Wang ET. Culturing C2C12 myotubes on micromolded gelatin hydrogels accelerates myotube maturation. Skelet Muscle 2019; 9:17. [PMID: 31174599 PMCID: PMC6555731 DOI: 10.1186/s13395-019-0203-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/30/2019] [Indexed: 12/17/2022] Open
Abstract
Background Skeletal muscle contributes to roughly 40% of lean body mass, and its loss contributes to morbidity and mortality in a variety of pathogenic conditions. Significant insights into muscle function have been made using cultured cells, in particular, the C2C12 myoblast line. However, differentiation of these cells in vitro typically yields immature myotubes relative to skeletal muscles in vivo. While many efforts have attempted to improve the maturity of cultured myotubes, including the use of bioengineered substrates, lack of molecular characterization has precluded their widespread implementation. This study characterizes morphological, molecular, and transcriptional features of C2C12 myotubes cultured on crosslinked, micropatterned gelatin substrates fabricated using previously established methods and compares them to myotubes grown on unpatterned gelatin or traditional plasticware. Methods We used immunocytochemistry, SDS-PAGE, and RNAseq to characterize C2C12 myotubes grown on micropatterned gelatin hydrogels, unpatterned gelatin hydrogels, and typical cell culture substrates (i.e., plastic or collagen-coated glass) across a differentiation time course. The ability to form aligned sarcomeres and myofilament protein concentration was assessed. Additionally, the transcriptome was analyzed across the differentiation time course. Results C2C12 myotubes grown on micropatterned gelatin hydrogels display an increased ability to form aligned sarcomeres as well as increased contractile protein content relative to myotubes cultured on unpatterned gelatin and plastic. Additionally, genes related to sarcomere formation and in vivo muscle maturation are upregulated in myotubes grown on micropatterned gelatin hydrogels relative to control myotubes. Conclusions Our results suggest that growing C2C12 myotubes on micropatterned gelatin hydrogels accelerates sarcomere formation and yields a more fully matured myotube culture. Thus, the use of micropatterned hydrogels is a viable and simple approach to better model skeletal muscle biology in vitro. Electronic supplementary material The online version of this article (10.1186/s13395-019-0203-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lance T Denes
- Department of Molecular Genetics and Microbiology, Center for Neurogenetics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Lance A Riley
- Department of Physiology and Functional Genomics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Joseph R Mijares
- Department of Physiology and Functional Genomics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Juan D Arboleda
- Department of Molecular Genetics and Microbiology, Center for Neurogenetics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Kendra McKee
- Department of Molecular Genetics and Microbiology, Center for Neurogenetics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Karyn A Esser
- Department of Physiology and Functional Genomics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for Neurogenetics, Myology Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
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17
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Entrenamiento de fuerza y resistencia en hipoxia: efecto en la hipertrofia muscular. BIOMEDICA 2019; 39:212-220. [PMID: 31021559 DOI: 10.7705/biomedica.v39i1.4084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 02/07/2023]
Abstract
El entrenamiento en altitud y el entrenamiento en hipoxia simulada producen adaptaciones fisiológicas y bioquímicas en el músculo esquelético como la capacidad oxidativa, así como modificaciones de la actividad mitocondrial, en el metabolismo aerobio y en el contenido de mioglobina.El propósito de esta revisión fue analizar las adaptaciones del músculo esquelético en respuesta a la exposición temporal a la hipoxia combinada con ejercicios de fuerza y resistencia. Según los hallazgos de numerosos autores, las adaptaciones estructurales del músculo son similares en la hipoxia y en la ‘normoxia’, con excepción de un aumento en el volumen muscular y en el área de la sección transversal de la fibra muscular, que son mayores en la hipoxia.En conclusión, la sinergia del entrenamiento de fuerza y resistencia y la hipoxia normobárica produce mejores y mayores adaptaciones, ganancias y cambios fisiológicos beneficiosos en el tejido muscular, lo cual genera cambios fenotípicos favorables, como la hipertrofia del músculo esquelético.
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18
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Rezvyakov PN, Shaimardanova GF, Lisukov AN, Kuznetsov MS, Islamov RR, Nikolskiy EE. Morphological Study of Myelinated Fibers of the Sciatic Nerve in Mice after Space Flight and Readaptation to the Conditions of Earth Gravity. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2018; 482:174-177. [PMID: 30402752 DOI: 10.1134/s0012496618050101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Indexed: 11/23/2022]
Abstract
We revealed a decrease in the thickness of the myelin sheath and myelin delamination in the tibial nerve of C57BL/6N mice after a 30-day flight aboard the biosatellite Bion-M1. The processes of myelin degeneration continued for seven days after return of the animals to Earth and adaptation to the conditions of natural gravity. Our data add to hypothesis on the role of neurogenic component in pathogenesis of hypogravity motor syndrome.
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Affiliation(s)
- P N Rezvyakov
- Kazan State Medical University, Kazan, Tatarstan, Russia.
| | - G F Shaimardanova
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Tatarstan, Russia
| | - A N Lisukov
- Kazan State Medical University, Kazan, Tatarstan, Russia
| | - M S Kuznetsov
- Kazan State Medical University, Kazan, Tatarstan, Russia
| | - R R Islamov
- Kazan State Medical University, Kazan, Tatarstan, Russia.,Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Tatarstan, Russia
| | - E E Nikolskiy
- Kazan State Medical University, Kazan, Tatarstan, Russia.,Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Tatarstan, Russia.,Kazan (Privolzhskii) Federal University, Kazan, Tatarstan, Russia
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19
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Tahir U, Hessel AL, Lockwood ER, Tester JT, Han Z, Rivera DJ, Covey KL, Huck TG, Rice NA, Nishikawa KC. Case Study: A Bio-Inspired Control Algorithm for a Robotic Foot-Ankle Prosthesis Provides Adaptive Control of Level Walking and Stair Ascent. Front Robot AI 2018; 5:36. [PMID: 33500922 PMCID: PMC7805871 DOI: 10.3389/frobt.2018.00036] [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: 11/17/2017] [Accepted: 03/19/2018] [Indexed: 11/30/2022] Open
Abstract
Powered ankle-foot prostheses assist users through plantarflexion during stance and dorsiflexion during swing. Provision of motor power permits faster preferred walking speeds than passive devices, but use of active motor power raises the issue of control. While several commercially available algorithms provide torque control for many intended activities and variations of terrain, control approaches typically exhibit no inherent adaptation. In contrast, muscles adapt instantaneously to changes in load without sensory feedback due to the intrinsic property that their stiffness changes with length and velocity. We previously developed a “winding filament” hypothesis (WFH) for muscle contraction that accounts for intrinsic muscle properties by incorporating the giant titin protein. The goals of this study were to develop a WFH-based control algorithm for a powered prosthesis and to test its robustness during level walking and stair ascent in a case study of two subjects with 4–5 years of experience using a powered prosthesis. In the WFH algorithm, ankle moments produced by virtual muscles are calculated based on muscle length and activation. Net ankle moment determines the current applied to the motor. Using this algorithm implemented in a BiOM T2 prosthesis, we tested subjects during level walking and stair ascent. During level walking at variable speeds, the WFH algorithm produced plantarflexion angles (range = −8 to −19°) and ankle moments (range = 1 to 1.5 Nm/kg) similar to those produced by the BiOM T2 stock controller and to people with no amputation. During stair ascent, the WFH algorithm produced plantarflexion angles (range −15 to −19°) that were similar to persons with no amputation and were ~5 times larger on average at 80 steps/min than those produced by the stock controller. This case study provides proof-of-concept that, by emulating muscle properties, the WFH algorithm provides robust, adaptive control of level walking at variable speed and stair ascent with minimal sensing and no change in parameters.
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Affiliation(s)
- Uzma Tahir
- Center for Bioengineering Innovation and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Anthony L Hessel
- Center for Bioengineering Innovation and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Eric R Lockwood
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
| | - John T Tester
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
| | - Zhixiu Han
- BionX Medical Technologies, Inc., Bedford, MA, United States
| | - Daniel J Rivera
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
| | - Kaitlyn L Covey
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States
| | - Thomas G Huck
- Center for Bioengineering Innovation and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Nicole A Rice
- Center for Bioengineering Innovation and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
| | - Kiisa C Nishikawa
- Center for Bioengineering Innovation and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
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20
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Mashinchian O, Pisconti A, Le Moal E, Bentzinger CF. The Muscle Stem Cell Niche in Health and Disease. Curr Top Dev Biol 2017; 126:23-65. [PMID: 29305000 DOI: 10.1016/bs.ctdb.2017.08.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The regulation of stem cells that maintain and regenerate postnatal tissues depends on extrinsic signals originating from their microenvironment, commonly referred to as the stem cell niche. Complex higher-order regulatory interrelationships with the tissue and factors in the systemic circulation are integrated and propagated to the stem cells through the niche. The stem cell niche in skeletal muscle tissue is both a paradigm for a structurally and functionally relatively static niche that maintains stem cell quiescence during tissue homeostasis, and a highly dynamic regenerative niche that is subject to extensive structural remodeling and a flux of different support cell populations. Conditions ranging from aging to chronically degenerative skeletal muscle diseases affect the composition of the niche and thereby impair the regenerative potential of muscle stem cells. A holistic and integrative understanding of the extrinsic mechanisms regulating muscle stem cells in health and disease in a broad systemic context will be imperative for the identification of regulatory hubs in the niche interactome that can be targeted to maintain, restore, or enhance the regenerative capacity of muscle tissue. Here, we review the microenvironmental regulation of muscle stem cells, summarize how niche dysfunction can contribute to disease, and discuss emerging therapeutic implications.
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Affiliation(s)
- Omid Mashinchian
- Nestlé Institute of Health Sciences, Lausanne, Switzerland; École Polytechnique Fédérale de Lausanne, Doctoral Program in Biotechnology and Bioengineering, Lausanne, Switzerland
| | - Addolorata Pisconti
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Emmeran Le Moal
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - C Florian Bentzinger
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada.
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21
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Nowack J, Giroud S, Arnold W, Ruf T. Muscle Non-shivering Thermogenesis and Its Role in the Evolution of Endothermy. Front Physiol 2017; 8:889. [PMID: 29170642 PMCID: PMC5684175 DOI: 10.3389/fphys.2017.00889] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 10/20/2017] [Indexed: 01/20/2023] Open
Abstract
The development of sustained, long-term endothermy was one of the major transitions in the evolution of vertebrates. Thermogenesis in endotherms does not only occur via shivering or activity, but also via non-shivering thermogenesis (NST). Mammalian NST is mediated by the uncoupling protein 1 in the brown adipose tissue (BAT) and possibly involves an additional mechanism of NST in skeletal muscle. This alternative mechanism is based on Ca2+-slippage by a sarcoplasmatic reticulum Ca2+-ATPase (SERCA) and is controlled by the protein sarcolipin. The existence of muscle based NST has been discussed for a long time and is likely present in all mammals. However, its importance for thermoregulation was demonstrated only recently in mice. Interestingly, birds, which have evolved from a different reptilian lineage than mammals and lack UCP1-mediated NST, also exhibit muscle based NST under the involvement of SERCA, though likely without the participation of sarcolipin. In this review we summarize the current knowledge on muscle NST and discuss the efficiency of muscle NST and BAT in the context of the hypothesis that muscle NST could have been the earliest mechanism of heat generation during cold exposure in vertebrates that ultimately enabled the evolution of endothermy. We suggest that the evolution of BAT in addition to muscle NST was related to heterothermy being predominant among early endothermic mammals. Furthermore, we argue that, in contrast to small mammals, muscle NST is sufficient to maintain high body temperature in birds, which have enhanced capacities to fuel muscle NST by high rates of fatty acid import.
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Affiliation(s)
- Julia Nowack
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Sylvain Giroud
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Walter Arnold
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Thomas Ruf
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
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Córdova Martínez A, Pascual Fernández J, Fernandez Lázaro D, Alvarez Mon M. Muscular and heart adaptations of execise in hypoxia. Is training in slow hypoxy healthy? Med Clin (Barc) 2017; 148:469-474. [PMID: 28341369 DOI: 10.1016/j.medcli.2017.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/02/2017] [Accepted: 02/09/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Alfredo Córdova Martínez
- Departamento de Bioquímica, Biología Molecular y Fisiología, Facultad de Fisioterapia, Campus Universitario de Soria, Universidad de Valladolid, Soria, España.
| | | | - Diego Fernandez Lázaro
- Departamento de Bioquímica, Biología Molecular y Fisiología, Facultad de Fisioterapia, Campus Universitario de Soria, Universidad de Valladolid, Soria, España
| | - Melchor Alvarez Mon
- Departamento de Medicina y Especialidades Médicas, Hospital Universitario Príncipe de Asturias, Universidad de Alcalá, Alcalá de Henares, Madrid, España
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23
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Comparative analysis of DNA methylome and transcriptome of skeletal muscle in lean-, obese-, and mini-type pigs. Sci Rep 2017; 7:39883. [PMID: 28045116 PMCID: PMC5206674 DOI: 10.1038/srep39883] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/29/2016] [Indexed: 02/07/2023] Open
Abstract
DNA methylation plays a pivotal role in biological processes by affecting gene expression. However, how DNA methylation mediates phenotype difference of skeletal muscle between lean-, obese-, and mini-type pigs remains unclear. We systematically carried out comparative analysis of skeletal muscle by integrating analysis of genome-wide DNA methylation, mRNA, lncRNA and miRNA profiles in three different pig breeds (obese-type Tongcheng, lean-type Landrace, and mini-type Wuzhishan pigs). We found that the differentially methylated genes (DMGs) were significantly associated with lipid metabolism, oxidative stress and muscle development. Among the identified DMGs, 253 genes were related to body-size and obesity. A set of lncRNAs and mRNAs including UCP3, FHL1, ANK1, HDAC4, and HDAC5 exhibited inversely changed DNA methylation and expression level; these genes were associated with oxidation reduction, fatty acid metabolism and cell proliferation. Gene regulatory networks involved in phenotypic variation of skeletal muscle were related to lipid metabolism, cellular movement, skeletal muscle development, and the p38 MAPK signaling pathway. DNA methylation potentially influences the propensity for obesity and body size by affecting gene expression in skeletal muscle. Our findings provide an abundant information of epigenome and transcriptome that will be useful for animal breeding and biomedical research.
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Kalliokoski P, Rodhe N, Bergqvist Y, Löfvander M. Long-term adherence and effects on grip strength and upper leg performance of prescribed supplemental vitamin D in pregnant and recently pregnant women of Somali and Swedish birth with 25-hydroxyvitamin D deficiency: a before-and-after treatment study. BMC Pregnancy Childbirth 2016; 16:353. [PMID: 27846821 PMCID: PMC5109741 DOI: 10.1186/s12884-016-1117-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 10/18/2016] [Indexed: 11/26/2022] Open
Abstract
Background Muscular weakness and severe vitamin D deficiency is prevalent in Somali (veiled) pregnant women, Sweden. The study aims here were to explore adherence to prescribed supplemental vitamin D in new mothers with vitamin D deficiency and its effects on grip strength and upper leg performance in Somali (target group TG) and Swedish women (reference group RG) from spring through winter. Methods A before- and after study was designed. A cross-sectional sample of women in antenatal care with serum 25-OHD ≤50 nmol/L were prescribed one or two tablets daily (800 or 1600 IU vitamin D3 with calcium) for 10 months. Reminders were made by Somali nurses (TG) or Swedish doctors (RG). Baseline and 10 month measurements of plasma nmol/L 25-OHD, maximal grip strength held for 10 s (Newton, N) and ability to squat (yes;no) were done. Total tablet intake (n) was calculated. Outcome variables were changes from baseline in grip strength and ability to squat. Predicting variables for change in grip strength and ability to squat were calculated using linear and binary regression in final models. Undetectable 25-OHD values (<10 nmol/L) were replaced with ‘9’ in statistic calculations. Results Seventy-one women (46 TG, 1/3 with undetectable baseline 25-OHD; 25 RG) participated. At the 10-month follow up, 17% TG and 8% RG women reported having refrained from supplement. Mean 25-OHD increased 16 to 49 nmol/L (TG) and 39 nmol/L to 67 nmol/L (RG), (both p < 0.001). Grip strength had improved from 153 to 188 N (TG) (p < 0.001) and from 257 to 297 N (RG) (p = 0.003) and inability to squat had decreased in TG (35 to 9, p < 0.001). Intake of number of tablets predicted increased grip strength (B 0.067, 95%CI 0.008–0.127, p = 0.027). One tablet daily (>300 in total) predicted improved ability to squat (OR 16; 95% CI 1.8–144.6). Conclusions Adherence to supplemental vitamin D and calcium should be encouraged as an even moderate intake was associated to improved grip strength and upper leg performance, which was particularly useful for the women with severe 25-OHD deficiency and poor physical performance at baseline. Trial registration ClinicalTrials.gov Identifier: NCT02922803. Date of registration: September 28, 2016.
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Affiliation(s)
- Paul Kalliokoski
- Primary Health Care Centre Jakobsgårdarna, Jaxtorget 7A, Box 100 33, S-781 10, Borlänge, Sweden. .,Centre for Clinical Research Dalarna, Falun, Sweden. .,Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden.
| | - Nils Rodhe
- Centre for Clinical Research Dalarna, Falun, Sweden.,Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden
| | | | - Monica Löfvander
- Uppsala University and Centre for Clinical Research Västmanland, Västerås, Sweden.,Division of Family Medicine, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.,Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden
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25
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Finite element model focused on stress distribution in the levator ani muscle during vaginal delivery. Int Urogynecol J 2016; 28:275-284. [PMID: 27562467 PMCID: PMC5306065 DOI: 10.1007/s00192-016-3126-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/02/2016] [Indexed: 11/17/2022]
Abstract
Introduction and hypothesis During vaginal delivery, the levator ani muscle (LAM) undergoes severe deformation. This stress can lead to stretch-related LAM injuries. The objective of this study was to develop a sophisticated MRI-based model to simulate changes in the LAM during vaginal delivery. Methods A 3D finite element model of the female pelvic floor and fetal head was developed. The model geometry was based on MRI data from a nulliparous woman and 1-day-old neonate. Material parameters were estimated using uniaxial test data from the literature and by least-square minimization method. The boundary conditions reflected all anatomical constraints and supports. A simulation of vaginal delivery with regard to the cardinal movements of labor was then performed. Results The mean stress values in the iliococcygeus portion of the LAM during fetal head extension were 4.91–7.93 MPa. The highest stress values were induced in the pubovisceral and puborectal LAM portions (mean 27.46 MPa) at the outset of fetal head extension. The last LAM subdivision engaged in the changes in stress was the posteromedial section of the puborectal muscle. The mean stress values were 16.89 MPa at the end of fetal head extension. The LAM was elongated by nearly 2.5 times from its initial resting position. Conclusions The cardinal movements of labor significantly affect the subsequent heterogeneous stress distribution in the LAM. The absolute stress values were highest in portions of the muscle that arise from the pubic bone. These areas are at the highest risk for muscle injuries with long-term complications.
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Yu H, Cowan CA. Minireview: Genome Editing of Human Pluripotent Stem Cells for Modeling Metabolic Disease. Mol Endocrinol 2016; 30:575-86. [PMID: 27075706 DOI: 10.1210/me.2015-1290] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pathophysiology of metabolic diseases such as coronary artery disease, diabetes, and obesity is complex and multifactorial. Developing new strategies to prevent or treat these diseases requires in vitro models with which researchers can extensively study the molecular mechanisms that lead to disease. Human pluripotent stem cells and their differentiated derivatives have the potential to provide an unlimited source of disease-relevant cell types and, when combined with recent advances in genome editing, make the goal of generating functional metabolic disease models, for the first time, consistently attainable. However, this approach still has certain limitations including lack of robust differentiation methods and potential off-target effects. This review describes the current progress in human pluripotent stem cell-based metabolic disease research using genome-editing technology.
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Affiliation(s)
- Haojie Yu
- Department of Stem Cell and Regenerative Biology (H.Y., C.A.C.), Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts 02138; and Center for Regenerative Medicine (C.A.C.), Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Chad A Cowan
- Department of Stem Cell and Regenerative Biology (H.Y., C.A.C.), Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts 02138; and Center for Regenerative Medicine (C.A.C.), Massachusetts General Hospital, Boston, Massachusetts 02114
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Shero MR, Costa DP, Burns JM. Scaling matters: incorporating body composition into Weddell seal seasonal oxygen store comparisons reveals maintenance of aerobic capacities. J Comp Physiol B 2015; 185:811-24. [PMID: 26164426 DOI: 10.1007/s00360-015-0922-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/24/2015] [Accepted: 07/02/2015] [Indexed: 12/24/2022]
Abstract
Adult Weddell seals (Leptonychotes weddellii) haul-out on the ice in October/November (austral spring) for the breeding season and reduce foraging activities for ~4 months until their molt in the austral fall (January/February). After these periods, animals are at their leanest and resume actively foraging for the austral winter. In mammals, decreased exercise and hypoxia exposure typically lead to decreased production of O2-carrying proteins and muscle wasting, while endurance training increases aerobic potential. To test whether similar effects were present in marine mammals, this study compared the physiology of 53 post-molt female Weddell seals in the austral fall to 47 pre-breeding females during the spring in McMurdo Sound, Antarctica. Once body mass and condition (lipid) were controlled for, there were no seasonal changes in total body oxygen (TBO2) stores. Within each season, hematocrit and hemoglobin values were negatively correlated with animal size, and larger animals had lower mass-specific TBO2 stores. But because larger seals had lower mass-specific metabolic rates, their calculated aerobic dive limit was similar to smaller seals. Indicators of muscular efficiency, myosin heavy chain composition, myoglobin concentrations, and aerobic enzyme activities (citrate synthase and β-hydroxyacyl CoA dehydrogenase) were likewise maintained across the year. The preservation of aerobic capacity is likely critical to foraging capabilities, so that following the molt Weddell seals can rapidly regain body mass at the start of winter foraging. In contrast, muscle lactate dehydrogenase activity, a marker of anaerobic metabolism, exhibited seasonal plasticity in this diving top predator and was lowest after the summer period of reduced activity.
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Affiliation(s)
- Michelle R Shero
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, 99508, USA. .,School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
| | - Jennifer M Burns
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, 99508, USA
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Hodge BA, Wen Y, Riley LA, Zhang X, England JH, Harfmann BD, Schroder EA, Esser KA. The endogenous molecular clock orchestrates the temporal separation of substrate metabolism in skeletal muscle. Skelet Muscle 2015; 5:17. [PMID: 26000164 PMCID: PMC4440511 DOI: 10.1186/s13395-015-0039-5] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/13/2015] [Indexed: 01/04/2023] Open
Abstract
Background Skeletal muscle is a major contributor to whole-body metabolism as it serves as a depot for both glucose and amino acids, and is a highly metabolically active tissue. Within skeletal muscle exists an intrinsic molecular clock mechanism that regulates the timing of physiological processes. A key function of the clock is to regulate the timing of metabolic processes to anticipate time of day changes in environmental conditions. The purpose of this study was to identify metabolic genes that are expressed in a circadian manner and determine if these genes are regulated downstream of the intrinsic molecular clock by assaying gene expression in an inducible skeletal muscle-specific Bmal1 knockout mouse model (iMS-Bmal1−/−). Methods We used circadian statistics to analyze a publicly available, high-resolution time-course skeletal muscle expression dataset. Gene ontology analysis was utilized to identify enriched biological processes in the skeletal muscle circadian transcriptome. We generated a tamoxifen-inducible skeletal muscle-specific Bmal1 knockout mouse model and performed a time-course microarray experiment to identify gene expression changes downstream of the molecular clock. Wheel activity monitoring was used to assess circadian behavioral rhythms in iMS-Bmal1−/− and control iMS-Bmal1+/+ mice. Results The skeletal muscle circadian transcriptome was highly enriched for metabolic processes. Acrophase analysis of circadian metabolic genes revealed a temporal separation of genes involved in substrate utilization and storage over a 24-h period. A number of circadian metabolic genes were differentially expressed in the skeletal muscle of the iMS-Bmal1−/− mice. The iMS-Bmal1−/− mice displayed circadian behavioral rhythms indistinguishable from iMS-Bmal1+/+ mice. We also observed a gene signature indicative of a fast to slow fiber-type shift and a more oxidative skeletal muscle in the iMS-Bmal1−/− model. Conclusions These data provide evidence that the intrinsic molecular clock in skeletal muscle temporally regulates genes involved in the utilization and storage of substrates independent of circadian activity. Disruption of this mechanism caused by phase shifts (that is, social jetlag) or night eating may ultimately diminish skeletal muscle’s ability to efficiently maintain metabolic homeostasis over a 24-h period. Electronic supplementary material The online version of this article (doi:10.1186/s13395-015-0039-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Brian A Hodge
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Lance A Riley
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Xiping Zhang
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Jonathan H England
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Brianna D Harfmann
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Elizabeth A Schroder
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
| | - Karyn A Esser
- Department of Physiology, College of Medicine, University of Kentucky, MS 508, 800 Rose Street, Lexington, KY 40536 USA ; Center for Muscle Biology, University of Kentucky, 800 Rose Street, Lexington, KY 40536 USA
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29
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Harfmann BD, Schroder EA, Esser KA. Circadian rhythms, the molecular clock, and skeletal muscle. J Biol Rhythms 2014; 30:84-94. [PMID: 25512305 DOI: 10.1177/0748730414561638] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Circadian rhythms are the approximate 24-h biological cycles that function to prepare an organism for daily environmental changes. They are driven by the molecular clock, a transcriptional:translational feedback mechanism that in mammals involves the core clock genes Bmal1, Clock, Per1/2, and Cry1/2. The molecular clock is present in virtually all cells of an organism. The central clock in the suprachiasmatic nucleus (SCN) has been well studied, but the clocks in the peripheral tissues, such as heart and skeletal muscle, have just begun to be investigated. Skeletal muscle is one of the largest organs in the body, comprising approximately 45% of total body mass. More than 2300 genes in skeletal muscle are expressed in a circadian pattern, and these genes participate in a wide range of functions, including myogenesis, transcription, and metabolism. The circadian rhythms of skeletal muscle can be entrained both indirectly through light input to the SCN and directly through time of feeding and activity. It is critical for the skeletal muscle molecular clock not only to be entrained to the environment but also to be in synchrony with rhythms of other tissues. When circadian rhythms are disrupted, the observed effects on skeletal muscle include fiber-type shifts, altered sarcomeric structure, reduced mitochondrial respiration, and impaired muscle function. Furthermore, there are detrimental effects on metabolic health, including impaired glucose tolerance and insulin sensitivity, which skeletal muscle likely contributes to considering it is a key metabolic tissue. These data indicate a critical role for skeletal muscle circadian rhythms for both muscle and systems health. Future research is needed to determine the mechanisms of molecular clock function in skeletal muscle, identify the means by which skeletal muscle entrainment occurs, and provide a stringent comparison of circadian gene expression across the diverse tissue system of skeletal muscle.
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Affiliation(s)
- Brianna D Harfmann
- Center for Muscle Biology, Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Elizabeth A Schroder
- Center for Muscle Biology, Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Karyn A Esser
- Center for Muscle Biology, Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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30
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Blaauw B, Schiaffino S, Reggiani C. Mechanisms modulating skeletal muscle phenotype. Compr Physiol 2014; 3:1645-87. [PMID: 24265241 DOI: 10.1002/cphy.c130009] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mammalian skeletal muscles are composed of a variety of highly specialized fibers whose selective recruitment allows muscles to fulfill their diverse functional tasks. In addition, skeletal muscle fibers can change their structural and functional properties to perform new tasks or respond to new conditions. The adaptive changes of muscle fibers can occur in response to variations in the pattern of neural stimulation, loading conditions, availability of substrates, and hormonal signals. The new conditions can be detected by multiple sensors, from membrane receptors for hormones and cytokines, to metabolic sensors, which detect high-energy phosphate concentration, oxygen and oxygen free radicals, to calcium binding proteins, which sense variations in intracellular calcium induced by nerve activity, to load sensors located in the sarcomeric and sarcolemmal cytoskeleton. These sensors trigger cascades of signaling pathways which may ultimately lead to changes in fiber size and fiber type. Changes in fiber size reflect an imbalance in protein turnover with either protein accumulation, leading to muscle hypertrophy, or protein loss, with consequent muscle atrophy. Changes in fiber type reflect a reprogramming of gene transcription leading to a remodeling of fiber contractile properties (slow-fast transitions) or metabolic profile (glycolytic-oxidative transitions). While myonuclei are in postmitotic state, satellite cells represent a reserve of new nuclei and can be involved in the adaptive response.
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Affiliation(s)
- Bert Blaauw
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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Schlagowski AI, Singh F, Charles AL, Gali Ramamoorthy T, Favret F, Piquard F, Geny B, Zoll J. Mitochondrial uncoupling reduces exercise capacity despite several skeletal muscle metabolic adaptations. J Appl Physiol (1985) 2014; 116:364-75. [DOI: 10.1152/japplphysiol.01177.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of mitochondrial uncoupling on skeletal muscle mitochondrial adaptation and maximal exercise capacity are unknown. In this study, rats were divided into a control group (CTL, n = 8) and a group treated with 2,4-dinitrophenol, a mitochondrial uncoupler, for 28 days (DNP, 30 mg·kg−1·day−1in drinking water, n = 8). The DNP group had a significantly lower body mass ( P < 0.05) and a higher resting oxygen uptake (V̇o2, P < 0.005). The incremental treadmill test showed that maximal running speed and running economy ( P < 0.01) were impaired but that maximal V̇o2(V̇o2max) was higher in the DNP-treated rats ( P < 0.05). In skinned gastrocnemius fibers, basal respiration (V0) was higher ( P < 0.01) in the DNP-treated animals, whereas the acceptor control ratio (ACR, Vmax/V0) was significantly lower ( P < 0.05), indicating a reduction in OXPHOS efficiency. In skeletal muscle, DNP activated the mitochondrial biogenesis pathway, as indicated by changes in the mRNA expression of PGC1-α and -β, NRF-1 and −2, and TFAM, and increased the mRNA expression of cytochrome oxidase 1 ( P < 0.01). The expression of two mitochondrial proteins (prohibitin and Ndufs 3) was higher after DNP treatment. Mitochondrial fission 1 protein (Fis-1) was increased in the DNP group ( P < 0.01), but mitofusin-1 and -2 were unchanged. Histochemical staining for NADH dehydrogenase and succinate dehydrogenase activity in the gastrocnemius muscle revealed an increase in the proportion of oxidative fibers after DNP treatment. Our study shows that mitochondrial uncoupling induces several skeletal muscle adaptations, highlighting the role of mitochondrial coupling as a critical factor for maximal exercise capacities. These results emphasize the importance of investigating the qualitative aspects of mitochondrial function in addition to the amount of mitochondria.
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Affiliation(s)
- A. I. Schlagowski
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
- CHRU of Strasbourg, Physiology and Functional Explorations Department, New Civil Hospital, Strasbourg, France; and
| | - F. Singh
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
| | - A. L. Charles
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
| | - T. Gali Ramamoorthy
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Physiological Genetics, Illkirch, France
| | - F. Favret
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
- CHRU of Strasbourg, Physiology and Functional Explorations Department, New Civil Hospital, Strasbourg, France; and
| | - F. Piquard
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
- CHRU of Strasbourg, Physiology and Functional Explorations Department, New Civil Hospital, Strasbourg, France; and
| | - B. Geny
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
- CHRU of Strasbourg, Physiology and Functional Explorations Department, New Civil Hospital, Strasbourg, France; and
| | - J. Zoll
- University of Strasbourg, Faculty of Medicine, FMTS, EA 3072, Strasbourg, France
- CHRU of Strasbourg, Physiology and Functional Explorations Department, New Civil Hospital, Strasbourg, France; and
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Hoppeler H, Baum O, Lurman G, Mueller M. Molecular mechanisms of muscle plasticity with exercise. Compr Physiol 2013; 1:1383-412. [PMID: 23733647 DOI: 10.1002/cphy.c100042] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The skeletal muscle phenotype is subject to considerable malleability depending on use. Low-intensity endurance type exercise leads to qualitative changes of muscle tissue characterized mainly by an increase in structures supporting oxygen delivery and consumption. High-load strength-type exercise leads to growth of muscle fibers dominated by an increase in contractile proteins. In low-intensity exercise, stress-induced signaling leads to transcriptional upregulation of a multitude of genes with Ca(2+) signaling and the energy status of the muscle cells sensed through AMPK being major input determinants. Several parallel signaling pathways converge on the transcriptional co-activator PGC-1α, perceived as being the coordinator of much of the transcriptional and posttranscriptional processes. High-load training is dominated by a translational upregulation controlled by mTOR mainly influenced by an insulin/growth factor-dependent signaling cascade as well as mechanical and nutritional cues. Exercise-induced muscle growth is further supported by DNA recruitment through activation and incorporation of satellite cells. Crucial nodes of strength and endurance exercise signaling networks are shared making these training modes interdependent. Robustness of exercise-related signaling is the consequence of signaling being multiple parallel with feed-back and feed-forward control over single and multiple signaling levels. We currently have a good descriptive understanding of the molecular mechanisms controlling muscle phenotypic plasticity. We lack understanding of the precise interactions among partners of signaling networks and accordingly models to predict signaling outcome of entire networks. A major current challenge is to verify and apply available knowledge gained in model systems to predict human phenotypic plasticity.
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Affiliation(s)
- Hans Hoppeler
- Institute of Anatomy, University of Bern, Bern, Switzerland.
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Fongy A, Romestaing C, Blanc C, Lacoste-Garanger N, Rouanet JL, Raccurt M, Duchamp C. Ontogeny of muscle bioenergetics in Adélie penguin chicks (Pygoscelis adeliae). Am J Physiol Regul Integr Comp Physiol 2013; 305:R1065-75. [DOI: 10.1152/ajpregu.00137.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ontogeny of pectoralis muscle bioenergetics was studied in growing Adélie penguin chicks during the first month after hatching and compared with adults using permeabilized fibers and isolated mitochondria. With pyruvate-malate-succinate or palmitoyl-carnitine as substrates, permeabilized fiber respiration markedly increased during chick growth (3-fold) and further rose in adults (1.4-fold). Several markers of muscle fiber oxidative activity (cytochrome oxidase, citrate synthase, hydroxyl-acyl-CoA dehydrogenase) increased 6- to 19-fold with age together with large rises in intermyofibrillar (IMF) and subsarcolemmal (SS) mitochondrial content (3- to 5-fold) and oxidative activities (1.5- to 2.4-fold). The proportion of IMF relative to SS mitochondria increased with chick age but markedly dropped in adults. Differences in oxidative activity between mitochondrial fractions were reduced in adults compared with hatched chicks. Extrapolation of mitochondrial to muscle respirations revealed similar figures with isolated mitochondria and permeabilized fibers with carbohydrate-derived but not with lipid-derived substrates, suggesting diffusion limitations of lipid substrates with permeabilized fibers. Two immunoreactive fusion proteins, mitofusin 2 (Mfn2) and optic atrophy 1 (OPA1), were detected by Western blots on mitochondrial extracts and their relative abundance increased with age. Muscle fiber respiration was positively related with Mfn2 and OPA1 relative abundance. Present data showed by two complementary techniques large ontogenic increases in muscle oxidative activity that may enable birds to face thermal emancipation and growth in childhood and marine life in adulthood. The concomitant rise in mitochondrial fusion protein abundance suggests a role of mitochondrial networks in the skeletal muscle processes of bioenergetics that enable penguins to overcome harsh environmental constraints.
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Affiliation(s)
- Anaïs Fongy
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
| | - Caroline Romestaing
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
| | - Coralie Blanc
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
| | - Nicolas Lacoste-Garanger
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
| | - Jean-Louis Rouanet
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
| | - Mireille Raccurt
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
| | - Claude Duchamp
- Université de Lyon, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1; Ecole Nationale des Travaux Publics de l'Etat; Centre National de la Recherche Scientifique, Villeurbanne, France
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Armstrong JB, Bond MH. Phenotype flexibility in wild fish: Dolly Varden regulate assimilative capacity to capitalize on annual pulsed subsidies. J Anim Ecol 2013; 82:966-75. [PMID: 23510107 DOI: 10.1111/1365-2656.12066] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 02/11/2013] [Indexed: 11/30/2022]
Abstract
1. Large digestive organs increase rates of energy gain when food is plentiful but are costly to maintain and increase rates of energy loss when food is scarce. The physiological adaptations to this trade-off differ depending on the scale and predictability of variation in food abundance. 2. Currently, there is little understanding of how animals balance trade-offs between the cost and capacity of the digestive system in response to resource pulses: rare, ephemeral periods of resource superabundance. We investigated the physiological and behavioural tactics of the fish Dolly Varden (Salvelinus malma) that rear in watersheds with low in situ productivity, but experience annual resource pulses from the spawning migrations of Pacific salmon. The eggs of Pacific salmon provide high-energy food for Dolly Varden. 3. Dolly Varden sampled 6 weeks prior to the resource pulse exhibited atrophy of the stomach, pyloric caeca, intestine and liver. Throughout the portion of the growing season prior to the resource pulse, fish exhibited empty stomachs, low indices of energy condition and muscle isotope signatures reflecting the previous resource pulse. 4. During the resource pulse, Dolly Varden exhibited large digestive machinery, gorged on salmon eggs and rapidly stored energy in fat reserves, somatic growth and gonad development. Dolly Varden appeared to achieve nearly their entire annual energy surplus during the ∼ 5-week period when sockeye salmon spawn. 5. Digestive flexibility provides Dolly Varden the energy efficiency required to survive and reproduce when resource abundance is concentrated into an annual pulse that is predictable, yet highly ephemeral. Although fish are known to incur extremely variable energy budgets, our study is one of the first to document digestive flexibility in wild fish. Our study emphasizes that fish can rely heavily on rare, high-magnitude foraging opportunities. Human actions that attenuate spikes in food abundance may have stronger than anticipated effects on consumer energy budgets.
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Affiliation(s)
- Jonathan B Armstrong
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA
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Billaut F, Gore CJ, Aughey RJ. Enhancing team-sport athlete performance: is altitude training relevant? Sports Med 2013; 42:751-67. [PMID: 22845561 DOI: 10.1007/bf03262293] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O(2)-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in contemporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes.
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Affiliation(s)
- François Billaut
- School of Sport and Exercise Science, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.
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Hudson NJ, Lyons RE, Reverter A, Greenwood PL, Dalrymple BP. Inferring the in vivo cellular program of developing bovine skeletal muscle from expression data. Gene Expr Patterns 2013; 13:109-25. [PMID: 23419240 DOI: 10.1016/j.gep.2013.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 12/01/2022]
Abstract
We outline an in vivo cellular program of bovine longissimus muscle development inferred from expression data from 60 days post conception to 3months postnatal. Analytic challenges included changes in cellular composition, ambiguous 'diagnostic' markers of cell type and contrasts between cattle human and mouse myogenesis. Nevertheless, the expression profiles of the myosin isoforms support slow and fast muscle fibres emanating from primary and secondary myogenesis respectively, while expression of the prenatal myosin subunits is down regulated prior to birth. Of the canonical pro-myogenic transcription factors (TF), MYF6 and MYF5 are negatively co-expressed, with MYF6 displaying higher expression in the post-natal samples and MYF5, MYOG, HES6 and PAX7 displaying higher expression in early development. A set of TFs (SIX1, EYA2 and DACH2) considered important in undifferentiated murine cells were equally abundant in differentiated bovine cells. An examination of mammalian regulators of fibre composition, muscle mass and muscle metabolism, underscored the roles of PPARGC1A, TGFβ signalling and the NHR4 Nuclear Hormone Receptors on bovine muscle development. Enriched among the most variably expressed genes from the entire data set were molecules regulating mitochondrial metabolism of carbohydrate (PDK4), fat (UCP3), protein (AGXT2L1) and high energy phosphate (CKMT2). The dramatic increase in the expression of these transcripts, which may enable the peri-natal transition to metabolic independence critical for new-born herbivores, provides surprising evidence for substantial developmental remodelling of muscle mitochondria and reflects changes in nutrient availability. Overall, despite differences in size, metabolism and physiology, the muscle structural subunit expression program appears very similar in ruminants, rodents and humans.
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Affiliation(s)
- Nicholas J Hudson
- Computational and Systems Biology Group, CSIRO Food Futures and CSIRO Animal, Food and Health Sciences, 306 Carmody Road, St. Lucia, QLD 4072, Australia.
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Abstract
A chain is no stronger than its weakest link is an old idiom that holds true for muscle biology. As the name implies, skeletal muscle's main function is to move the bones. However, for a muscle to transmit force and withstand the stress that contractions give rise to, it relies on a chain of proteins attaching the cytoskeleton of the muscle fiber to the surrounding extracellular matrix. The importance of this attachment is illustrated by a large number of muscular dystrophies caused by interruption of the cytoskeletal-extracellular matrix interaction. One of the major components of the extracellular matrix is laminin, a heterotrimeric glycoprotein and a major constituent of the basement membrane. It has become increasingly apparent that laminins are involved in a multitude of biological functions, including cell adhesion, differentiation, proliferation, migration and survival. This review will focus on the importance of laminin-211 for normal skeletal muscle function.
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Affiliation(s)
- Johan Holmberg
- Muscle Biology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden.
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Webster KN, Dawson TJ. The high aerobic capacity of a small, marsupial rat-kangaroo (Bettongia penicillata) is matched by the mitochondrial and capillary morphology of its skeletal muscles. J Exp Biol 2012; 215:3223-30. [PMID: 22660784 DOI: 10.1242/jeb.071365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We examined the structure-function relationships that underlie the aerobic capacities of marsupial mammals that hop. Marsupials have relatively low basal metabolic rates (BMR) and historically were seen as 'low energy' mammals. However, the red kangaroo, Macropus rufus (family Macropodidae), has aerobic capacities equivalent to athletic placentals. It has an extreme aerobic scope (fAS) and its large locomotor muscles feature high mitochondrial and capillary volumes. M. rufus belongs to a modern group of kangaroos and its high fAS is not general for marsupials. However, other hopping marsupials may have elevated aerobic capacities. Bettongia penicillata, a rat-kangaroo (family Potoroidae), is a small (1 kg), active hopper whose fAS is somewhat elevated. We examined the oxygen delivery system in its muscles to ascertain links with hopping. An elevated fAS of 23 provided a relatively high maximal aerobic oxygen consumption ( ) in B. penicillata; associated with this is a skeletal muscle mass of 44% of body mass. Ten muscles were sampled to estimate the total mitochondrial and capillary volume of the locomotor muscles. Values in B. penicillata were similar to those in M. rufus and in athletic placentals. This small hopper had high muscle mitochondrial volume densities (7.1-11.9%) and both a large total capillary volume (6 ml kg(-1) body mass) and total capillary erythrocyte volume (3.2 ml kg(-1)). Apparently, a considerable aerobic capacity is required to achieve the benefits of the extended stride in fast hopping. Of note, the ratio of to total muscle mitochondrial volume in B. penicillata was 4.9 ml O(2) min(-1) ml(-1). Similar values occur in M. rufus and also placental mammals generally, not only athletic species. If such relationships occur in other marsupials, a fundamental structure-function relationship for oxygen delivery to muscles likely originated with or before the earliest mammals.
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Affiliation(s)
- Koa N Webster
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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Votion DM, Gnaiger E, Lemieux H, Mouithys-Mickalad A, Serteyn D. Physical fitness and mitochondrial respiratory capacity in horse skeletal muscle. PLoS One 2012; 7:e34890. [PMID: 22529950 PMCID: PMC3329552 DOI: 10.1371/journal.pone.0034890] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 03/08/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Within the animal kingdom, horses are among the most powerful aerobic athletic mammals. Determination of muscle respiratory capacity and control improves our knowledge of mitochondrial physiology in horses and high aerobic performance in general. METHODOLOGY/PRINCIPAL FINDINGS We applied high-resolution respirometry and multiple substrate-uncoupler-inhibitor titration protocols to study mitochondrial physiology in small (1.0-2.5 mg) permeabilized muscle fibres sampled from triceps brachii of healthy horses. Oxidative phosphorylation (OXPHOS) capacity (pmol O(2) • s(-1) • mg(-1) wet weight) with combined Complex I and II (CI+II) substrate supply (malate+glutamate+succinate) increased from 77 ± 18 in overweight horses to 103 ± 18, 122 ± 15, and 129 ± 12 in untrained, trained and competitive horses (N = 3, 8, 16, and 5, respectively). Similar to human muscle mitochondria, equine OXPHOS capacity was limited by the phosphorylation system to 0.85 ± 0.10 (N = 32) of electron transfer capacity, independent of fitness level. In 15 trained horses, OXPHOS capacity increased from 119 ± 12 to 134 ± 37 when pyruvate was included in the CI+II substrate cocktail. Relative to this maximum OXPHOS capacity, Complex I (CI)-linked OXPHOS capacities were only 50% with glutamate+malate, 64% with pyruvate+malate, and 68% with pyruvate+malate+glutamate, and ~78% with CII-linked succinate+rotenone. OXPHOS capacity with glutamate+malate increased with fitness relative to CI+II-supported ETS capacity from a flux control ratio of 0.38 to 0.40, 0.41 and 0.46 in overweight to competitive horses, whereas the CII/CI+II substrate control ratio remained constant at 0.70. Therefore, the apparent deficit of the CI- over CII-linked pathway capacity was reduced with physical fitness. CONCLUSIONS/SIGNIFICANCE The scope of mitochondrial density-dependent OXPHOS capacity and the density-independent (qualitative) increase of CI-linked respiratory capacity with increased fitness open up new perspectives of integrative and comparative mitochondrial respiratory physiology.
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LaRosa DA, Cannata DJ, Arnould JPY, O'Sullivan LA, Snow RJ, West JM. Changes in muscle composition during the development of diving ability in the Australian fur seal. AUST J ZOOL 2012. [DOI: 10.1071/zo11072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
During development the Australian fur seal transitions from a terrestrial, maternally dependent pup to an adult marine predator. Adult seals have adaptations that allow them to voluntarily dive at depth for long periods, including increased bradycardic control, increased myoglobin levels and haematocrit. To establish whether the profile of skeletal muscle also changes in line with the development of diving ability, biopsy samples were collected from the trapezius muscle of pups, juveniles and adults. The proportions of different fibre types and their oxidative capacity were determined. Only oxidative fibre types (Type I and IIa) were identified, with a significant change in proportions from pup to adult. There was no change in oxidative capacity of Type I and IIa fibres between pups and juveniles but there was a two-fold increase between juveniles and adults. Myoglobin expression increased between pups and juveniles, suggesting improved oxygen delivery, but with no increase in oxidative capacity, oxygen utilisation within the muscle may still be limited. Adult muscle had the highest oxidative capacity, suggesting that fibres are able to effectively utilise available oxygen during prolonged dives. Elevated levels of total creatine in the muscles of juveniles may act as an energy buffer when fibres are transitioning from a fast to slow fibre type.
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Shero MR, Andrews RD, Lestyk KC, Burns JM. Development of the aerobic dive limit and muscular efficiency in northern fur seals (Callorhinus ursinus). J Comp Physiol B 2011; 182:425-36. [PMID: 22001970 DOI: 10.1007/s00360-011-0619-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/16/2011] [Accepted: 09/19/2011] [Indexed: 10/17/2022]
Abstract
Northern fur seal (Callorhinus ursinus; NFS) populations have been declining, perhaps due to limited foraging ability of pups. Because a marine mammal's proficiency at exploiting underwater prey resources is based on the ability to store large amounts of oxygen (O(2)) and to utilize these reserves efficiently, this study was designed to determine if NFS pups had lower blood, muscle, and total body O(2) stores than adults. Pups (<1-month old) had a calculated aerobic dive limit only ~40% of adult females due to lower blood and, to a much greater extent, muscle O(2) stores. Development of the Pectoralis (Pec) and Longissimus dorsi (LD) skeletal muscles was further examined by determining their myosin heavy chain (MHC) composition and enzyme activities. In all animals, the slow MHC I and fast-twitch IIA proteins typical of oxidative fiber types were dominant, but adult muscles contained more (Pec ~50%; LD ~250% higher) fast-twitch MHC IID/X protein characteristic of glycolytic muscle fibers, than pup muscles. This suggests that adults have greater ability to generate muscle power rapidly and/or under anaerobic conditions. Pup muscles also had lower aerobic and anaerobic ATP production potential, as indicated by lower metabolically scaled citrate synthase, β-hydroxyacyl CoA dehydrogenase, and lactate dehydrogenase activities (all P values ≤0.001). In combination, these findings indicate that pups are biochemically and physiologically limited in their diving capabilities relative to adults. This may contribute to lower NFS first year survival.
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Affiliation(s)
- Michelle R Shero
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA.
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Abstract
Mammalian skeletal muscle comprises different fiber types, whose identity is first established during embryonic development by intrinsic myogenic control mechanisms and is later modulated by neural and hormonal factors. The relative proportion of the different fiber types varies strikingly between species, and in humans shows significant variability between individuals. Myosin heavy chain isoforms, whose complete inventory and expression pattern are now available, provide a useful marker for fiber types, both for the four major forms present in trunk and limb muscles and the minor forms present in head and neck muscles. However, muscle fiber diversity involves all functional muscle cell compartments, including membrane excitation, excitation-contraction coupling, contractile machinery, cytoskeleton scaffold, and energy supply systems. Variations within each compartment are limited by the need of matching fiber type properties between different compartments. Nerve activity is a major control mechanism of the fiber type profile, and multiple signaling pathways are implicated in activity-dependent changes of muscle fibers. The characterization of these pathways is raising increasing interest in clinical medicine, given the potentially beneficial effects of muscle fiber type switching in the prevention and treatment of metabolic diseases.
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Affiliation(s)
- Stefano Schiaffino
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Consiglio Nazionale delle Ricerche Institute of Neurosciences, and Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
| | - Carlo Reggiani
- Venetian Institute of Molecular Medicine, Department of Biomedical Sciences, University of Padova, Consiglio Nazionale delle Ricerche Institute of Neurosciences, and Department of Human Anatomy and Physiology, University of Padova, Padova, Italy
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Nielsen S, Scheele C, Yfanti C, Akerström T, Nielsen AR, Pedersen BK, Laye MJ, Laye M. Muscle specific microRNAs are regulated by endurance exercise in human skeletal muscle. J Physiol 2011; 588:4029-37. [PMID: 20724368 DOI: 10.1113/jphysiol.2010.189860] [Citation(s) in RCA: 218] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Muscle specific miRNAs, myomiRs, have been shown to control muscle development in vitro and are differentially expressed at rest in diabetic skeletal muscle. Therefore, we investigated the expression of these myomiRs, including miR-1, miR-133a, miR-133b and miR-206 in muscle biopsies from vastus lateralis of healthy young males (n = 10) in relation to a hyperinsulinaemic–euglycaemic clamp as well as acute endurance exercise before and after 12 weeks of endurance training. The subjects increased their endurance capacity, VO2max (l min−1) by 17.4% (P < 0.001), and improved insulin sensitivity by 19% (P < 0.01). While myomiR expression remained stable during a hyperinsulinaemic–euglycaemic clamp, an acute bout of exercise increased mir-1 (P < 0.05) and mir-133a (P < 0.05) expression before, but not after, training. In resting biopsies, endurance training for 12 weeks decreased basal expression of all four myomiRs (P < 0.05). Interestingly, all myomiRs reverted to their pre-training expression levels 14 days after ceasing the training programme. Components of major pathways involved in endurance adaptation such as MAPK and TGF-β were predicted to be targeted by the myomiRs examined. Tested predicted target proteins included Cdc42 and ERK 1/2. Although these proteins were downregulated between post-training period and 2 weeks of cessation, an inverse correlation between myomiR and target proteins was not found. In conclusion, our data suggest myomiRs respond to physiological stimuli, but their role in regulating human skeletal muscle adaptation remains unknown.
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Affiliation(s)
- Søren Nielsen
- The Centre of Inflammation and Metabolism, Department of Infectious Diseases and CMRC, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Denmark.
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Burns JM, Skomp N, Bishop N, Lestyk K, Hammill M. Development of aerobic and anaerobic metabolism in cardiac and skeletal muscles from harp and hooded seals. ACTA ACUST UNITED AC 2010; 213:740-8. [PMID: 20154189 DOI: 10.1242/jeb.037929] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In diving animals, skeletal muscle adaptations to extend underwater time despite selective vasoconstriction include elevated myoglobin (Mb) concentrations, high acid buffering ability (beta) and high aerobic and anaerobic enzyme activities. However, because cardiac muscle is perfused during dives, it may rely less heavily on Mb, beta and anaerobic pathways to support contractile activity. In addition, because cardiac tissue must sustain contractile activity even before birth, it may be more physiologically mature at birth and/or develop faster than skeletal muscles. To test these hypotheses, we measured Mb levels, beta and the activities of citrate synthase (CS), beta-hydroxyacyl-CoA dehydrogenase (HOAD) and lactate dehydrogenase (LDH) in cardiac and skeletal muscle samples from 72 harp and hooded seals, ranging in age from fetuses to adults. Results indicate that in adults cardiac muscle had lower Mb levels (14.7%), beta (55.5%) and LDH activity (36.2%) but higher CS (459.6%) and HOAD (371.3%) activities (all P<0.05) than skeletal muscle. In addition, while the cardiac muscle of young seals had significantly lower [Mb] (44.7%) beta (80.7%) and LDH activity (89.5%) than adults (all P<0.05), it was relatively more mature at birth and weaning than skeletal muscle. These patterns are similar to those in terrestrial species, suggesting that seal hearts do not exhibit unique adaptations to the challenges of an aquatic existence.
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Affiliation(s)
- J M Burns
- Department of Biological Sciences, University of Alaska, Anchorage, AK 99508, USA.
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Prewitt JS, Freistroffer DV, Schreer JF, Hammill MO, Burns JM. Postnatal development of muscle biochemistry in nursing harbor seal (Phoca vitulina) pups: limitations to diving behavior? J Comp Physiol B 2010; 180:757-66. [PMID: 20140678 DOI: 10.1007/s00360-010-0448-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 01/12/2010] [Accepted: 01/15/2010] [Indexed: 10/19/2022]
Abstract
Adult marine mammal muscles rely upon a suite of adaptations for sustained aerobic metabolism in the absence of freely available oxygen (O(2)). Although the importance of these adaptations for supporting aerobic diving patterns of adults is well understood, little is known about postnatal muscle development in young marine mammals. However, the typical pattern of vertebrate muscle development, and reduced tissue O(2) stores and diving ability of young marine mammals suggest that the physiological properties of harbor seal (Phoca vitulina) pup muscle will differ from those of adults. We examined myoglobin (Mb) concentration, and the activities of citrate synthase (CS), beta-hydroxyacyl coA dehydrogenase (HOAD), and lactate dehydrogenase (LDH) in muscle biopsies from harbor seal pups throughout the nursing period, and compared these biochemical parameters to those of adults. Pups had reduced O(2) carrying capacity ([Mb] 28-41% lower than adults) and reduced metabolically scaled catabolic enzyme activities (LDH/RMR 20-58% and CS/RMR 29-89% lower than adults), indicating that harbor seal pup muscles are biochemically immature at birth and weaning. This suggests that pup muscles do not have the ability to support either the aerobic or anaerobic performance of adult seals. This immaturity may contribute to the lower diving capacity and behavior in younger pups. In addition, the trends in myoglobin concentration and enzyme activity seen in this study appear to be developmental and/or exercise-driven responses that together work to produce the hypoxic endurance phenotype seen in adults, rather than allometric effects due to body size.
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Affiliation(s)
- J S Prewitt
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Dr, Anchorage, AK 99508, USA.
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Moyes CD, Genge CE. Scaling of muscle metabolic enzymes: an historical perspective. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:344-50. [PMID: 20138152 DOI: 10.1016/j.cbpa.2010.01.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 01/29/2010] [Accepted: 01/30/2010] [Indexed: 11/26/2022]
Abstract
In this paper, we take an historical approach to reviewing research into the patterns of metabolic enzymes in muscle in relation to body size, focusing on mitochondrial enzymes. One of the first studies on allometric scaling of muscle enzymes was published in an early issue of this journal (George and Talesara, 1961 Comp. Biochem. Physiol. 3: 267-273). These researchers studied a number of locally available birds and a bat, measuring the activity of the mitochondrial enzyme succinate dehydrogenase in relation to body mass and muscle structure. Though the phenomenon of allometric scaling of metabolism was well recognized even 50 years earlier, this study was one of the first to explore the enzymatic underpinnings of the metabolic patterns in different animals. In this review, we begin by considering the George and Talesara study in the context of this early era in metabolic biochemistry and comparative physiology. We review subsequent studies in the last 50 years that continued the comparative analysis of enzyme patterns in relation to body size in diverse experimental models. This body of work identified a recurrent (though not ubiquitous) reciprocal relationship between oxidative and glycolytic enzymes. In the last 10 years, studies have focused on identifying the molecular mechanisms that determine the muscle metabolic enzyme phenotype.
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Affiliation(s)
- Christopher D Moyes
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
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Affiliation(s)
- Douglas S Glazier
- Department of Biology, Juniata College, Huntingdon, Pennsylvania 16652, USA.
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48
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Lundby C, Calbet JAL, Robach P. The response of human skeletal muscle tissue to hypoxia. Cell Mol Life Sci 2009; 66:3615-23. [PMID: 19756383 PMCID: PMC11115669 DOI: 10.1007/s00018-009-0146-8] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 08/20/2009] [Indexed: 12/13/2022]
Abstract
Hypoxia refers to environmental or clinical settings that potentially threaten tissue oxygen homeostasis. One unique aspect of skeletal muscle is that, in addition to hypoxia, oxygen balance in this tissue may be further compromised when exercise is superimposed on hypoxia. This review focuses on the cellular and molecular responses of human skeletal muscle to acute and chronic hypoxia, with emphasis on physical exercise and training. Based on published work, it is suggested that hypoxia does not appear to promote angiogenesis or to greatly alter oxidative enzymes in skeletal muscle at rest. Although the HIF-1 pathway in skeletal muscle is still poorly documented, emerging evidence suggests that muscle HIF-1 signaling is only activated to a minor degree by hypoxia. On the other hand, combining hypoxia with exercise appears to improve some aspects of muscle O(2) transport and/or metabolism.
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Affiliation(s)
- Carsten Lundby
- The Copenhagen Muscle Research Centre, Rigshospitalet Sect. 7652, 2100, Copenhagen, Denmark.
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Flueck M. Tuning of mitochondrial pathways by muscle work: from triggers to sensors and expression signatures. Appl Physiol Nutr Metab 2009; 34:447-53. [PMID: 19448713 DOI: 10.1139/h09-034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Performance of striated muscle relies on the nerve-driven activation of the sarcomeric motor and coupled energy supply lines. This biological engine is unique; its mechanical and metabolic characteristics are not fixed, but are tailored by functional demand with exercise. This remodelling is specific for the imposed muscle stimulus. This is illustrated by the increase in local oxidative capacity with highly repetitive endurance training vs. the preferential initiation of sarcomerogenesis with strength training regimes, where high-loading increments are imposed. The application of molecular biology has provided unprecedented insight into the pathways that govern muscle plasticity. Time-course analysis indicates that the adjustments to muscle work involve a broad regulation of transcript expression during the recovery phase from a single bout of exercise. Highly resolving microarray analysis demonstrates that the specificity of an endurance-exercise stimulus is reflected by the signature of the transcriptome response after muscle work. A quantitative match in mitochondrial transcript adjustments and mitochondrial volume density after endurance training suggests that the gradual accumulation of expressional microadaptations underlies the promotion of fatigue resistance with training. This regulation is distinguished from control of muscle growth via the load-dependent activation of sarcomerogenesis. Discrete biochemical signalling systems have evolved that sense metabolic perturbations during exercise and trigger a specific expression program, which instructs the remodelling of muscle makeup. A drop in muscle oxygen tension and metabolite perturbations with exercise are recognized as important signals in the genome-mediated remodelling of the metabolic muscle phenotype in humans.
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Affiliation(s)
- Martin Flueck
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Oxford Road, Manchester M15 6BH, UK.
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Gerth N, Sum S, Jackson S, Starck JM. Muscle plasticity of Inuit sled dogs in Greenland. ACTA ACUST UNITED AC 2009; 212:1131-9. [PMID: 19329747 DOI: 10.1242/jeb.028324] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study examined flexible adjustments of skeletal muscle size, fiber structure, and capillarization in Inuit sled dogs responding to seasonal changes in temperature, exercise and food supply. Inuit dogs pull sleds in winter and are fed regularly throughout this working season. In summer, they remain chained to rocks without exercise, receiving food intermittently and often fasting for several days. We studied two dog teams in Northern Greenland (Qaanaaq) where dogs are still draught animals vital to Inuit hunters, and one dog team in Western Greenland (Qeqertarsuaq) where this traditional role has been lost. Northern Greenland dogs receive more and higher quality food than those in Western Greenland. We used ultrasonography for repeated muscle size measurements on the same individuals, and transmission electron microscopy on micro-biopsies for summer-winter comparisons of muscle histology, also within individuals. At both study sites, dogs' muscles were significantly thinner in summer than in winter - atrophy attributable to reduced fiber diameter. Sarcomeres from West Greenland dogs showed serious myofilament depletion and expansion of the sarcoplasmatic space between myofibrils during summer. At both study sites, summer samples showed fewer interfibrillar and subsarcolemmal mitochondria, and fewer lipid droplets between myofibrils, than did winter samples. In summer, capillary density was higher and inter-capillary distance smaller than in winter, but the capillary-to-fiber-ratio and number of capillaries associated with single myofibers were constant. Increased capillary density was probably a by-product of differential tissue responses to condition changes rather than a functional adaptation, because thinning of muscle fibers in summer was not accompanied by reduction in the capillary network. Thus, skeletal muscle of Inuit dogs responds flexibly to changes in functional demands. This flexibility is based on differential changes in functional components: mitochondrial numbers, lipid droplet size, and the number of contractile filaments all increase with increasing workload and food supply while the capillary network remains unchanged.
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Affiliation(s)
- Nadine Gerth
- Department of Biology II, University of Munich (LMU), 82152 Planegg-Martiensried, Germany.
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